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Functional object in low poly - program and tutorial
I'm losing my mind, it all started out with the idea of a project where I want an abstract shape (I'm going to call it a stretched cube with an angle), now I know a bit of Vectorworks - a 3D/Architecture drawing program. I found nothing in all the tutorials how to make something low poly but still be able to for example screw the bottom of with a thread for example.
I found numerous shapes I like on Thingiverse but they are all STL files which I've learned so far are hard to edit and make them functionally usable when cross transferring them for one to another program.
Today I gave it another try to find other programs which can give me the result and functionality I want. Thus far I've only found program where you make the shape perfectly and then by using a mesh program like 123make and Meshmixer to then change the outcome of the rendering. But in my case this makes some parts unable to use anymore as example the threading?
So for the question I their a program which I can make a low poly shape (example below) where I still can add holes and threading like you can do with AutoCAD, Vectorworks.
I hope somebody knows how to do this I've been searching and asking around for weeks!!
This is an example of the type of shape I would like to create, Low poly vase - mine would be exactly the same but it would be to give you an idea
Example of the thread I would like to implement in the shape above, Tap and Die for 3D printed threads

Perhaps try asking the users who posted to this question. I'm not familiar with the process you're requesting but it sounds like something Blender or MeshLab might be able to help with.

Yes, you can accomplish threading easily with something like 3Ds Max, Blender, Maya etc. I use Maya personally so, in Maya, all you have to do is:

Create a cylinder. This will be the main body of your 'screw'.
To make the thread, you need to create a helix primitive. You can edit the number of coils and the coil thickness in the Maya GUI.
Once you have the thread, it is a simple matter of performing a couple of boolean operations. The first boolean (union) operation will unite the screw made in step 1 with the thread made in step 2. The second boolean (subtract) operation will cut out the thread from the object within which you want your screw to be driven into. When you print the two models, you should find that the screw nicely turns into the object from which you cut out the thread.

The point is: yes, it is easy to do such things in most 3D software packages. Maya comes with a nice selection of default objects you can use, so essentially you need to do no 'modeling' yourself to create something like the example you showed us.
Your next question, about editing models on Thingiverse. The reason why you cannot edit them easily is because most models there have been decimated and triangulated, which makes them very difficult to reshape or edit because the topology is no longer strictly manifold -- it is just a big mess of triangles!
If you want to edit Thingiverse models, I recommend something like ZBrush. You can import triangulated models and then rebuild the geometry into quads (using DynaMesh, for example), which you can then edit to your liking. Once done, you can simply decimate and re-export as STL or whatever extension you need.
Finally, low/high poly is not so relevant in 3D print outs, especially in mechanically functioning parts. This is because most models are created in high resolution (high polygon count) and then decimated + triangulated down to truncate file sizes. But the functionality and physical feel of the model should not change due to this process - it just takes practice and lots of experimentation.
Hope this helps :)
Hassan

I've had my share of struggles with the issues you're having - bridging the software gap between hard-edge, parametric modeling tools (typically CAD) and more free-form, 'soft'/organic, modeling tools. It's not a trivial task to work across both domains simultaneously.
The simplest workflow I've developed is:

Create a simple CAD model of parts of the object you're trying to make that have mechanical/precision features (e.g. threaded screw holes, joints) in a CAD program (e.g. AutoCAD, Inventor, Solidworks, Fusion 360).
Export a high-precision STL of those parts
Create/generate the 'soft'/organic portions of the model in your software suite of choice (e.g. Blender, Maya)
Export an OBJ file (or STL, if the option is available) of the 'soft' parts
Import both sets of parts into Meshmixer and combine them there.
Export to a single, combined STL
(Optional) Pass the 'end product' STL through a model "fixer" - I quite like the Microsoft Model Repair Service

Meshmixer is a powerful but poorly documented tool. In my experience, it's capable of accomplishing most of the basic "fixes" most models need in preparation for 3d-printing. It is possible to do some amount of sculpting/organic modeling within Meshmixer itself but you'll probably find it inferior in that regard to other software suites, if you know how to use them.

If you have some programming background, take a look at OpenScad.   It allows you to model using a functional programming language.  Basically all of the customizer models on Thingiverse are written in openscad.  My gut says you can use the poly command to string together a bunch of polygons to do what you want.


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3D printer calibration test STLs?
Is there any well-known test set of 3D models that I can print out which will clearly show up the problems I need to work out in calibrating my 3D printer? Ideally, it would be either one or multiple models which shows the point at which overhanging starts to fail, points at which stringing occurs, the accuracy of one layer over another, and maybe edges which are supposed to be a particular length.

Yes.
There are more test models one can download than would be possible to list here. A search on Thingiverse results in pages and pages of useful models. A common model for testing is called the 3d Benchy, although it is not particularly parametric. Overhangs, retraction, layer alignment and other aspects of your printer are tested with this model.
Another option is to purchase a set of test models from 3dkitbash.com:
QuickPrintTests
The models lists as such:
#3dk01 - Voids
#3dk02 - Spikes
#3dk03 - Flex
#3dk04 - Edge
#3dk05 - Text
#3dk06 - Bridge
#3dk07 - Dissolve
#3dk08 - Ball Joint
#3dk09 - Hinge
#3dk10 - Columns

which are more specifically defined for testing your printer. I would expect that Thingiverse and other model-sharing sites would have similar designs available to meet your specific requirements.

The QuickPrintTests is fantastic, and is exactly what I'm looking for but isn't free.

The 3dkitbash people are in the business of selling their creative work. Considering how challenging it is to make models, especially organic models such as their creatures and "puppets," it's not too much of a surprise that they would charge for the calibration modules. You may be able to find similar models on the model sharing sites, and you have a good reference with their list.

I've found this free test build that also includes the specific tests accomplished:
http://www.thingiverse.com/thing:1363023

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Bronze Filament Problem
I made a torus that was 1 on the x and y axes, and 3 on the z axis in Blender. It is supposed to be a bead for a beaded necklace. It was exported to Cura as an .stl, then printed on a Lulzbot Mini. It worked fine in plastic, but when we tried it with bronze filament the nozzle clogged and it didn't start printing.
Is there something I need to add to the model that will provide instructions for the printer? The person who operates the printer says that most, but not all, of the models he prints in bronze have a border around them when they print, and this one didn't. I don't know if that makes a difference.

Since we do not know more about the printer and its settings it is most likely that the issues lies within the printer and the temperature/print speed settings. Fill materials do print differently than just colored plastic of the same type. Find valid print parameters for the type of filament that you can modify as needed for the printer that is being used (a good first gauge are the offsets the printer has for other type of filaments (thermistors might be offset for example) added to the 'literature values' of the new filament).
It might also be, that the nozzle was not clean when changing filaments and hence the clogging occured. Have you/your printing guy tried a 'cold pull'? How should I clean my extruder when changing materials?
Usually nozzle clogging comes down to knowledge about your printer and experience with the filament.

We print a lot of stuff in a variety of materials, and I think it is likely what you are experiencing is a problem caused by some combination of the following: Object size overall, object detail size, wall thickness, or span width/thickness.
Blender gives pretty clean stls, but the last-mile needed to get output is primarily a materials engineering problem.... (and saying thias, I am assuming you got a valid stl that the printer was able to read and rip...)
A first thought: Try loading your stl into one of the services that price online. Shapeways does, and Cubify does or did... and you can download the driver software for the Form2 even if you don't own the printer.
Bring your stl into these apps and look for error messages. The Shapeways ordering app does a nice job of showing issues, particularly ones like wall thickness and manifold faces/vertices (another possibility I did not mention above) very quickly.
I'd offer to look at your stl if it is something you can share... and/or you can ask your output guy for a sample stl he has printed with some success before. Bring that stl file into Blender beside your model and compare.
I do not recognize a "border" around stls, but all of the printers have preferences for the support sprues that support the model as it is built.... possible that he means these?
In any case, shout if I can help. We have used a lot of materials, but some of them take tweaking -- most often with detail size (how small of a detail you can recreate on the rpinted surface) and step size (how small the steps are inbetween printed layers in additive rinting systems.
Or... just chuck it onto a CNC with a big ole' block of bronze and machine it down!  That's pretty old school, but it works, too... just by removing material rather than adding.
Here's a torus at Shapeways I uploaded....

Sorry -- error messages you'd get from a different service might be helpful in diagnosing your issue -- but might not be applicable, either. I was just thinking of ways to confirm your stl file's validity in the wider 3D printing world.

The border that the operator is most likely referring to is called a brim or skirt and is typically handled by the Slicing software that the operator uses to convert the 3D solid model into the machine code for the 3D printer to run.
I'd recommend double checking the settings in Cura for a brim/skirt. This function will make the machine print a small outer layer a few millimeters away from the part itself. The outer layer gets the filament flowing and hopefully will dislodge any clogs the machine might have.

Yes.  And with a new or difficult material, it might be worth using the printer's LCD menu (if present) or control software to manually extrude some filament before even trying to run a part file at all.  On some printers you have to do this by commanding it to heat the nozzle and then finding the menu where you can move the extruder (or it is geared, disables the steppers and turn it by hand).  On others, there's a move filament or manual extrude setting that achieves temperature and movement together.

Yeah, I've manually extruded filament on my Replicator before and most often it's been a good indicator that my drive gear needs to be cleaned. For instance, I'll manually extrude the filament using the LCD, but it takes a little force at first to get it going. However when the print starts and the stepper motor makes such small increments, it's not able to catch onto the filament. So, I disassemble the extruder to clean the drive gear and all is good.

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How do I determine that the electronics are working with the test firmware?

You may want to use this code to test all the electronics before
  installing any of the suggested firmwares.

From Final Step in the RAMPS 1.4 Wiki

There's a bunch of code in the sketch, and it looks to me like it just makes a component run, or heat up, for a little but and then move on to the next component, and do the same thing is that about right?
Well if I'm testing this out and my printer is already for the most part assembled; should I set the stepper jumpers to something larger like a full turn, or half step, so I can see the motors move?  Because I've also read that if you're going to test things out you shouldn't even be hooking up but one of the stepper drivers in case you burn one out!

Running this kind of test isn't really necessary; it provides a nice test to see if everything is working but so does uploading actual firmware (and this isn't any safer than traditional firmware, at that).
It looks like it runs the steppers in one direction for 5 seconds and then in reverse for 5, which should be more than enough to see them move even with 1/32 stepping (it moves them at 1 step/ms, which would come out to 3/4ths of a turn with 1/200 steppers and 1/32 microstepping).
It isn't necessary to remove any code that isn't used. It does no harm.

If I'm just testing a motor with one stepper, with just the 5A plugged in, should I disable the code that deals with the other components before testing?


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What does the trimpot on my Switching Power Supply do?
On my Switching Power Supply there is a little orange trimpot that's marked VR1; what does that do, and does it work similar to the ones on the stepper drivers?

No doubt it's just a final tuning potentiometer. Even on the pictures you linked it's described as V adj which stands for voltage adjustment.
It's a way to tune your power supply's output as it can vary depending on temperature/humidity/wall-plug voltage/etc.
It's usually set properly and doesn't need to be touched. But you can connect a multimeter to check if your power supply gives the voltage you need.
If you are not familiar with the subject but still want to do it yourself, it's good to set your multimeter to the highest available range and make sure that AC/DC is properly chosen.  Now you can measure voltage. You can set the range closer to the expected values then. Usually multimeters have a range around 20 or 30V DC which is propbably what you expect from your power supply. In such a range you should see something like 12.000. If it varies from 12.000 you can then precisely adjust it to get as close as possible to this value. But watch out... cheap power supplies can cheat you. When the are have a load on the output (your 3D printer for example) they can reduce voltage.

Vr usually stands for variable resistor, basically a pot. Usually by adjusting this you would adjust the voltage output on most power supplies, ensure you double check your voltage output with a meter after adjusting.


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Solidoodle 4 voltage requirements
I have a solidoodle 4 and have blown the power supply . Long and the short of it is I am trying to modify a Xbox 1 power supply to fulfill the need. I am measuring he voltage at the output and its 14.04 volt.
Question is this, is the operational voltage range on a solidoodle able to operate on 14 volt ?

Do you have the specifications of either the original power supply or the expected input voltage of the printer? There seem to be a complete void of information on this online, unfortunately. If you have the specifications at hand, it would be nice if you updated the question. Also, if you don't get any answers here, consider asking this question on the Electrical Engineering SE site as well.

Hi tormod, the original power supply was 12 volt

I don't know what the expected input voltage for the printer is.

As a follow up to this query, I am operating the printer now on the modified power supply , haven't done any really long prints as I am still working through the calibration process, had to move to a new computer as well, so I am restarting my setup from scratch. Main part is the Xbox one power supply works and does not appear to have any bad ramifications

I think I have accepted it.

Glad to hear that the information I dug up was able to help and worked out in the case of your new power supply! Happy printing!

I have not used or seen a solidoodle 4, but as found on the internet, the controller board used in the printer is a version of the Sanguinololu, and the reprap wiki says that

The board is designed to be flexible in its power source, working with
  a 12V/5V ATX power supply or any 7V-35V power source via the on-board
  voltage regulator.

if you're using a board not older than V0.7 http://reprap.org/wiki/Sanguinololu
However, I have also found images that show the Solidoodle with this board:
http://www.reprap.org/wiki/SAV_MKI
which can be used with 11-15V. This however might be for older versions of the printer.
There are some things to keep in mind: if there is no voltage regulator on the board, make sure that all parts can take the voltage without overheating at some points.

Hi kamuro, thanks for the information, you had much more luck tracking down info than I did,  my printer is about 2 years old , pretty sure it's one of the newer ones but I will verify the firmware tonight . I decided after the old power supply went south I was going to try to upgrade it a bit to give some additional amps and the Xbox 1 power supply seems to fit the bill for the most part.


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What does a "3 h5" mean in reference to the axle of a motor?
Sorry if this isn't the right place to ask, but it seemed like the most relevant stackexchange.
I want to print a connection from a motor to an omniwheel, the axle of the wheel is listed as 8mm, but the one of the motor only say "3h5" which isn't really helpful for me, and neither was Google.
Side-question: Would pla be sturdy enough or do I need to use abs?

Please refrain from asking multiple unrelated questions in a single answer. To preserve the accuracy and usefulness of the site please create a new question for Would pla be sturdy enough or do I need to use abs?. Thank you and welcome to 3D Printing SE!

Okay, sorry, haven't use stackexchange that much.

No problem, everyone's new at some point. Glad I could help

I think it's a reference to a tolerance. Look at this ISO table. This States that the nominal diameter of 3mm is held to a tolerance of +-0.004mm.
@DarthPixel provided some great links identifying the term interference fit (or press fit as I've heard locally) as described here. Also, here is a better link providing examples of how the tolerance works and more legible tables to reference the correct tolerance. Keep in mind that the units in the tables is in nanometers.

exactly. here is wiki page which describes it and IMO better (more readable table)

Thank you for the references. I was on the mobile app when I posted the answer. I'll add your links to my answer shortly.


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Power Supply Safety
I just recently purchased a new MightyBoard (Rev G) for my Replicator that requires a new power supply.
The power supply for the Rev E was a 24 V/9.2 A which was necessary for the dual extruders and heated bed. I know I need a 24 V power supply, but should I be concerned about the amperage? What will a higher (or lower) rating affect on my machine?

If this is the Geeetech "RevG" board, it's not really a proper RevG. Geeetech just modified the RevE board a bit and unilaterally changed the name without considering the fact that there already was a RevG Mightyboard from Makerbot. So they're in violation of the open source license (not releasing updates source files) and confusing people and from what I hear, it's a pretty bad board too.

I suggest looking at the maximum amperage draw for all components that could be on at one time, and then find a power supply that can supply at least 20% more current.  You would never want to get a supply rated for lower current than your max draw, because then it will affect the torque or your motors, or the temperature to which your heaters can get.
Think of it like this: An outlet at home may be rated at 115V/20A.  Your blender is not going to draw the full 20A; having a little extra never hurts.  But if you try to run a large appliance (dryer, hot tub, etc.) on a smaller amp circuit, the breaker would blow because you are trying to draw more than it can supply.
The point is, get something rated for higher than you need, within reason.  It will draw only what it needs.
Pro tip:  Make sure to set the current limits on your stepper motor drivers for maximum performance!

Simple answer sounds like this: lower (too low) rating can cause your replicator won't work properly, higher won't cause it. Too high will never be used by your machine so it's the case of spending money. But as @Thetravellingfool you should always have some reserve.

Note, Mightyboards use digipots for current control, so you don't need to adjust the driver currents. Unless you have a goofy modified version that accepts Pololus.

A short, figurative answer from the electronical point of view:
A power supply (an an analogy you can view it as a water pump) as used by 3D printers is usually supplying a fixed voltage (a constant pressure going into your pipe system), in your case 24V.
The given amperage/current (the amount of water that actually flows) that is actually utilized at a given point in time is determined by whatever you hook up to your power supply (the system of tubes or pipes - imagine a valve like your tap/faucet). Now the amperage rating of your power supply gives how much current you can run through your electrical system (as is the flow of your tap/faucet by the pump if you had a limitless big, imigainative one).
The power that your supply can deliver is the product of voltage and amperage: P(power) = U(voltage)*I(current).
What you need to make sure is that a) you deliver the correct voltage, because this is what your circuitry needs to be specifically designed for (image the pressure of your pump being too low or to high, - you either won't recieve any water in the second floor, or your tubing can't stand the pressure) and b) that you can supply at least the needed power (otherwise you get a problem once you open up all the taps/faucets in your house, because they don't supply as much water as demanded). If your power supply can give more current, that's fine, it might just not be used. And as mentioned by Thetravellingfool already, keep a certain plus for losses and as a reserve, because no pump likes to run constantly at it's limits either ;)

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Is there any way to shrink 3 mm filaments down to 2.85 mm?
Some 3 mm filaments seem to actually be 3 mm - is there any way to shave off the excess and use it as 2.85 mm?

I would not recommend you to try and somehow re-size the filament, since even the smallest of irregularities and error in diameter occurring from such a process would ruin your prints with sporadic over and under extrusion. Rather, if you have the tools available, you could grind the filament into pellets, and use a filament extruder to make it anew with your desired diameter.
Alternatively, depending on your printer setup, you might very well extrude true 3.00 filament with your 2.85 mm filament printer. If you try to do that, make sure to:

Adjust filament diameter in your slicer
Check that your filament isn't getting squashed by the extruder wheel
Check that all mechanical parts actually can pass through your filament freely

I do not own a 2.85 mm printer myself, and therefore have not tried this procedure. There are, however, several people who seem to have done this successfully.

I think the errors would depend on the process - I agree there are risks, but a proper process shouldn't have such issues - making pellets and going from there is indeed one way that shouldn't have such issues

You will need to melt it push it through a hopper, screw thread,
then draw it out at a constant pressure, with a water bath plus a sensor to check diameter.

you could put a 3 mm extruder on you're printer. or (if you're r brave) put route filament in the oven for 10 minutes and unroll it than stretch it out. if you do this outside you can attach one ent to a stride licht or something an pul on the other end, if it is hot anoth it should hold its new position. but don't get it to hot or the filament will stick to itself, you can put talk powder on it to prevent this but be shore to watch it off before using your filament. i have never tried this and not komw is it will work. you can try it on i short pease of about 2 m first to test it oud. if it works, please tell me. i would love to know.

It's a joke right? Producing filament with a requested diam is very delicate process. Puting filament to oven is very bad idea. I vote -1 for this answer.

you can at least try it, if you have nothing to loze

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Can a short-circuited heat bed be salvaged?
I was working on my printer when something metallic came into contact with the pcb. I smelled smoke and quickly unplugged the printer. Anyway, this is the result and, of course, the heat bed won't heat.
Can this be salvaged or should I toss it and buy a new one?

update the heat bed was not hot at the time. I had the heat bed unscrewed from the chassis but had forgotten to unplug the printer. I am not exactly sure how it shorted but I think it shorted between the power lead connection and the thermistor.

FYI I have already ordered a new one for $20 but I still want to see if I can fix this one for the experience.

Worth noting here that all heaters in a 3D printer are always energized with positive voltage. The ground side is what is switched. So shorting any heater element to ground will cause current to flow, whether or not it's "on."

@RyanCarlyle what is the difference as it's in fact a resistor? According to my knowledge it doesn't matter if you change polarity (checked on Mk2 HB - as same as in the case). The only difference is that LED is lit or not.

@darthpixel Doesn't make any functional difference in normal use whether V+ or GND is switched. But it's a big safety difference. The entire heatbed circuit is always energized with respect to ground, so any short to ground at any time with the system powered will cause Bad Things. If you switched V+ instead, the heatbed would be safely grounded and inert when not actively being heated by the controller.

@RyanCarlyle I still don't get how it influence on the case of fixing HB. The problem is not how to do it according to all possible standards but to recognize if it can be fixed (make to heat again). Nevertheless I still suppose there are 2 heaters with common pin1. This asumption is made on the table all HB has painted with (which i linked in my answer). (take a look on my [edit2])

@darthpixel Oh, sorry for the confusion, I wasn't trying to say anything about your proposed fix. Just commenting on the question -- the fact that the heatbed was "off" doesn't mean it's de-energized. It's an important safety note for people when working on the printer, cleaning build plates, etc.

This sounds like the precursor to settings ones house on fire ...

Hello @zkent, I noticed your question has been up for a while now. Have any of the answers below been able to solve your question? If so, would you mind accepting the appropriate answer. If not, what is missing so that we may help you further? Also, if you have figured it out on your own, you can always answer and accept your own solution. Thank you.

What happend was short circuit of course. There is no doubt you overheated HB so copper detached from HB base plate. Because you wrote it doesn't work it means copper tracks are broken.
There is very low chance to fix it. I mean it - near to zero.
What you could do is:

Detach HB from arduino
Find a place where track is broken (which needs to uncover it from protective layer)
Connect it with a wire

Unfortunately even if you do it and your HB will work (electrically) your fixed HB which won't be flat anymore.
So definitely it's to be thrown away.
[edit]
I just realised you have double power HB, which means your HB has 2 heaters... which gives a bit hope.
take a look here

here is schematics which could give you an idea
You could check if your second heater works ok
If yes then you are salvaged! :)
[edit2]
I really suppose the schematics of HB is more or less like this

So if H1 is broken there is a chance to use H2 connecting pins respectively

Isn't that track only for the sensor in the middle?  On the other side of the pcb, at the end of those tracks is the thermistor.

@zkent My understanding of this circuit is that there are 2 heaters. #1 between pin 1 and 2 and second between pin 1 and 3. It means pin 1 is common. One of these heaters is broken so try to use second pair. (pairs are 1-2, 1-3)

It will still be flat after the repair if you remount it with the heating tracks on the bottom.  That will also help spread out any localized heat difference from a bypassed section.

Yes, it should be possible to fix, although you might choose to replace anyway on the basis that the repaired bed might give you concerns about how long it will be before your repair fails.
You will need to carefully remove the protective layer to expose the heating element (assuming you can identify where it is likely to have broken). Then carefully solder across the break (maybe with a short fragment of wire).
After making the repair, you should cover the exposed track. This provides both electrical and thermal insulation. In the absence of any suitable high-temperature paintable covering, you could try using kapton tape.


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Trend in Filament Costs?
Some have suggested that filament costs are asymptotically approaching a baseline cost - others that costs are linearly decreasing. Does anyone know where to find the trending costs on a single class of filament over the past decade or more?
Part of the reason we are asking is to get enough longitudinal data to begin projecting costs for printing objects in the future. You might think of it like the "Moore's Law" of filament costs.

This might be a better question for Open Data SE

I'm not clear as to the intent of your question, but I would like to provide some insight. Typically, the biggest differentiating factor between a mediocre data scientist, and a good one, is based on the hypothesis they put forth. Therefore, understanding where the cost of filament is derived from is much more important than analyzing the market price equilibrium over a period of time (Even if done with consideration to various filament types).
Here are some basic costs:

Raw material (the cost based on region, and grade)
Manufacturing scale (Mixers, extruders, cooling, spooling, packaging, etc.)
Shipping (Often 50% of cost for small quantities)
Supply chain (Number of middle men)

Without going into detail of every preceding point, I was able to break down costs to a theoretical $10/kg for ABS, if starting with virgin pellets, and shipping flat rate USPS within the US.
The point that I am trying to make is, fundamentals over technical analysis in this case.

You could have a look though the various price trackers for Amazon (like ccc and thetractor), for some basic trends. Most of them does not seem to have sufficient data to give any valuable insight, but that could change.
In general, I would refer to the yearly and monthly trend reports found on 3D Hubs. They usually include the average filament order costs per filament type from the previous 30 days, although they do not display it as a continuous graph at this time.

Any particular reason for the downvote? Please comment.

I don't understand the downvote either. Have an upvote from me.


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Would appreciate advice on unclogging hot end [Makerbot Replicator v2]
My Makerbot Replicactor V2 constantly jams. Usually when I go to use it after it's been off for a few hours the filament has jammed and I have to take off the front fan to remove the filament. Today, after going through the usual rigmarole of having to take the front fan and fan guard off, remove the filament, cut it and then load it back in I found that there was another problem.
It appears something is jammed inside the hot end itself. When I loaded the filament back into the machine, it took it but nothing came out of the nozzle, instead it all pooled up around the aluminium mounting block where the filament feeds through.

Here's a couple more pictures, the last one is basically what happens to me on a regular basis: https://i.stack.imgur.com/sZ784.jpg
How should I go about fixing this? I've already cleaned the extruder nozzle, but unsure as how best to proceed with this. I would prefer to get this fixed fairly soon as I need to 3d print files for a uni assessment piece.

For molten filament to jam at the inlet to the thermal barrier tube like shown here, there must be something wrong with the cooling in your setup. The cold zone needs to be cool for the extruder to work right. It looks like the cold zone is not staying below the glass point of the plastic, so the filament softens and mashes into a jam.
Here are some common causes of jamming in Replicator 2 extruders:

Printer's environment is too hot. If it's in a hot garage, move it indoors. If you have it inside an enclosure or cabinet, open it up to let it breathe. All-metal extruders with PLA are very sensitive to ambient temp.
Not having good contact between the heatsink and the cooling bar. Normally, just bolting them together is fine, but a small amount of of thermal grease (like Arctic Silver) smeared over the contact surface can help too.
Not having the fan pointed the right way. You want the fan to blow ONTO the heatsink: this provides more turbulent flow and better cooling. This means you should not see the fan sticker when everything is assembled.
Fan dying and and spinning too slow. A new fan can be a good idea. (24v fans only!) Or you can try gently peeling off the fan sticker and adding a single drop of light oil (like 3-in-one) to the bearing, then re-attaching the sticker.
Using non-stock thermal barrier tubes that do not have the correct internal geometry. Lots of people sell bad tubes that don't have the "secret sauce" (internal diameter step). The four good vendors I'm aware of for this part are Makerbot, Carl Raffle, Micro Swiss, and Performance 3D.
"Floating" the thermal barrier threads by tightening jam nuts on both top and bottom of the cooling bar. All-metal extruder designs require good contact pressure between the thermal barrier tube threads and the cooling bar, to ensure maximum heat transfer. The best approach is to put one jam nut below the bar to forcibly push the thermal barrier tube threads into the cooling bar, and no nut on top. (Using just one nut on top is better than two nuts, but worse than one nut below.)

It's also possible that there is some material partially blocking the nozzle, which is contributing to molten plastic backup up and jamming.
What I would recommend right now is removing both the nozzle and thermal barrier tube from the printer, and either replacing them or fully cleaning them out. There are multiple options. You can preheat the hot end with the cooling bar in a vise or on a metal surface with no fans attached, to heat up the plastic in the thermal barrier tube and allow you to push the blockage through with a small allen key. Then do something to REALLY clean it out, like nylon cold-pulls, or cooking the parts in a blue flame such as a torch or gas stove. Then check for internal debris with something like a toothpick.
Once you can see through the nozzle orifice and there's no junk inside anything, reassemble everything properly and try again.


text:
Choose infill percentage
Since I'm running a 3D printing facility of an engineering school, students are always wondering how much infill percentage affects the stiffness of the part. I know that it is impossible to get a numerical solution for this question, but maybe there is an option to simulate in software an already sliced model. I haven't seen in any slicer an option to export as .stl or .step or any other format which can be accepted by simulation software. Has anyone seen or thought about something similar?

I don't believe that slicing engines create any sort of solid model that would be useful for CAD simulation. When a slicing engine slices a 3D model, it's goal is to spit out the preferred machine paths in G-Code (of some kind). However, I've read a few articles, done some tests, and heard through the grape vine that anywhere between 10%-35% is good enough for most applications. I once watched a webinar for understanding the new MakerWare interface that explained how they chose such settings. Although I can't find the clip directly, here is the page for all of MakerBot's webinars. I think this webinar was the one I watched explaining a little bit about preferred infill percentages.
From experience, anything over 35% doesn't yield much more strength from infill side of things. Beyond 35% and you're going to want to reconsider how you're orienting the print when you print it and what you're printing to utilize the grain structure for proper strength.
However, infill percentage/patterns are not the only variable for creating strong parts. Infill is really just a way to save time and material. Here are some other ways to potentially increase strength:

Increase your shell. Shell is the number of profile patterns per layer. Typically (in FDM/FFF), each shell is about the diameter of your extruder nozzle.
Increase your floor/roof. Similar to shell, floor/roof refers to the number of layers that make up the "bottom" and "top" of the part with regard to the build plate.
Print orientation. Pay attention to which areas of the part are susceptible to strain along the "grain" of the layers. Try to rotate your part on the build plate in a way that minimizes potential failure both in print and post-print use.
Post process. Don't be afraid to do some post-processing to increase the strength. There are some 3D printers on the market that go as far as including Kevlar strands in the printing process to beef up their prints. However, it may be as simple as just coating the part in an epoxy with some basic finishing techniques. It's a bit more work, but it turns weak 3D printed parts into full production quality prints.

Update:
Based on some of the comments, it sounds like your best bet might be to find a custom application that can either convert the g-code file into a solid model (try CAM software?), or create a plugin for your CAD software (I know Unigraphics NX and Solidworks allow for this) and essentially recreate your own slicing engine that takes your solid model and generates the same infill pattern dynamically inside.
Perhaps look into the works of Simlab or similar which has a lot of 3D software plugins. I'm not promoting them and I don't work for them, this is just a reference of what to look for.

Thanks for link, I'll check it out. For engineering applications we need precise data, at least it is required by project description. Engineers can relay on some experiments and experience, but it would be much more reliable source of information, to slice your part and then by simulation prove that this parameters will withstand such a load.

You could potentially print your own tensile bars and test different infill % in-house. However, it will greatly depend with the source of the material and shell parameters.

For bending loads, which are the primary failure mode in real printed parts (because they concentrate tension on the surface of the object where the layer lines present plentiful fracture initiation sites), adding perimeters is significantly more impactful than adding infill. This behavior is kind of masked in standard tensile tests, but you'll see it in a four-bar bending test.

Thanks for elaborating on perimeters, I forgot to really emphasise that

Of course with bars it  can be done by printing test bars. But problem is that shapes are always different, and there are no possibility to print thousands of test parts for each of projects. So that I though about software which can simulate stiffness of already sliced part.

@AntonOsadchy are you referring the various project parts are in shapes [that] are always different or that there is a distinguishable difference in how a 3D printer prints the same part (ie. a test bar)? If it's the latter, you'd benefit from double checking your machine meets the requirements of your particular field (idk what your tolerances are).

I have totally different orders, with different requirements. Shapes are always different because Mechanics of each of projects is unique. And now we have just two options, print solid if there is some mechanical load on part or 20-30% infill for housings, cases and etc. Some of parts, for instance, should not necessary be solid, but there are no tool which can help to determine printing parameters for it, so we print them solid (spending more time and resources).

Thanks for update. I'll definitely take a look and let you know, how it will go :)

Since I am not able to comment on this question yet, I thought I would provide an answer in addition to the already helpful insight provided.
If the question in general is regarding infill percentage, and the common follow-up regards part stiffness, then it should be explained that choosing infill percentage is much more than just part stiffness.
Printing out tensile bars would be a great thing to have for educational purposes. The bars should not only vary in infill percentages, but in also the various infill patterns. Depending on the type of stresses and loads applied, different patterns may be stronger at lower infill rates, for example.
Also, the infill rate should correlate to the thickness of the bottom, top, and sidewalls. This is especially important with ABS when it comes to shrinkage, warping, and delayering. In order for the part to be universally as strong as possible, as the part cools, it must shrink evenly. This is a well known factor for machinists creating molds for injection molding and casting. Otherwise, you may have unintended additional points of weaknesses arise.
Lastly, if creating tensile bars, make sure to take into account the shrinkage experienced along each axis, for each individual example. I would also suggest cutting each one open, as well as attempting to break a few of the apart (in a very crude way). This could stimulate a lot of thought when designing a part, before printing it.

Anton, I parse the G-code and build a finite element model and a thermal transient event to simulate the printing of the part, followed by a structural simulation to determine the deformation and stress state in the resulting part. This part could then be further analyzed with external loads to determine mechanical characteristics. I use ANSYS software and the element birth & death capability to activate a small volume of material per each thermal transient step. The structural sim is static but also done at the same time steps as the thermal transient.

Wow! That sounds very complicated and is probably a bit too advanced for most of our users. It would be very interesting if you could tell us what you learnt from these simulations (some rules-of-thumb and perhaps some statistics) because not many people will be able to replicate this.

Thanks man! I have an experience with ANSYS, so I can try it. The only question is - How did you imported g-code to Ansys simulation?

I could think of a way. But it might require a few softwares to get everything done.
First get the CAD file.
Import to magics (Materialise proprietary software)
There is a function for structures, you can build your custom internal structure. So add trusses etc.
Export stl. (There is one software which allows direct stl to step conversion, I think its called Instep)
Or i think you could reduce mesh density and use FreeCAD to convert it back to step and run your analysis.
It would be intersting to see a report on the part.
Also there is no good way of simulating a 3d printed part.
Maybe the closest would be with composites.

If you're an engineering class, you may very well print out big cubes of different infils and test them.

The OP mentioned in some of the comments that testing is not feasible as new tests would need to be conducted for each new part. The part geometry and requirements vary such that a few tensile bars would not cover the engineering requirements. Perhaps elaborate on the process you mentioned to potentially aid others in the future?

This should be a comment.

You have to do it by eye. However you need to think about what infill you use. a triangle pattern will be very strong.
Following I never use high infill. Most of my items have a strong outer shell, IE 3 layers. Inside I will do between 7 and 14 %. If I printed a square 200mm^3 I would have no concerns standing on it.
All depends. Really though for your settings I would not thing you would really ever need more than 14%.
At a company I worked at that was testing 3d printed parts. They evaluated material by printing the same test shapes and seeing what their tolerances were. You will need to develop your own method as such.


text:
What are the modifications on this Kossel?
(This question is a kind of self-answer. I know who built this printer, he explained the modifications, and I thought it might be interesting for others too. I've asked him to answer this question, to keep this information on Stack Exchange. I realize this question in its current form may be "Too Broad", feel free to edit to make it more specific).

I saw this Kossel Mini printer, and noted that it has some modifications. I'm told this is to make it easier to transport, and would like to know how these modifications make it more robust and more transportable.

I am voting to close this question as "unclear what you're asking" because it is impossible for somebody (who doesn't just happen to be the particular builder of this printer) to tell what modifications are on there from just that single picture. I think this question is also too broad (it would be better to ask a question about a specific modification like what kind of extruder is on there).

This technically could be placed in Meta as it does bring up a good point of where questions like this have a place (if at all) in SE

@tbm0115 Some of the entertainment sites (e.g. anime.SE) have identification requests. I think this question is a variant of these. They have rules about id requests - we could discuss if we need such rules here as well.

On SE.Robotics I have seen some questions that are of the type "Please identify this robot arm/grabber/etc.". Cool Kossel BTW! :-)

Cool you placed my Kossel Mini on Stackexchange!
What I have modified to the standard kit:

Retractable probe using RC Marlin (Rich Cattels Marlin with auto bed probe functionality). Never have to adjust endstops after it is once setup.
All can be done in firmware.
Made a transport case, in the picture the cover is missing which is a triangular case which fits over the printer.
You can clip it on and the carry it with the handle on top.
I just throw it in the car and bring it to the Hackerspace and Hackerevents/Makerfaires and when I feel to it, I can do an auto-probe to align it again (which is hardly needed BTW)
Another mod is the Vaeder extruder, which is really cool in the way it uses a GT2 timing belt to drive the filament. It uses a round wheel and it drives the filament over 1/4 of the diameter of the wheel, so there is a 3 to 4 cm area where the belt drives the filament.

Advantages:

Lots of retracts don't "eat" into the filament causing feed issues
Doesn't flatten the filament. Keeps it nice and round.

Disadvantages (at this moment):

Not possible/ very hard to do filament swaps on the fly (to experiment with multicolor prints).
First time assembly can be a head ache, once you have it assembled it really works and is easy going.

And last but not least. I made a foldable Roll holder.
It is mounted on top by two M8 screws with knobs. When I am done I undo these two screws, fold in the roll holder and it is then mounted to the side of the flight case. This way I can transport printer and roll holder carrying it only using 1 hand. So I use the other hand carrying the bag with accessories like rolls of filament, 3D spray, tweezers etc.
Maybe this info helps other people new to 3D printing improve their printers, or enables them to bring printers more easily to meets and events to inspire others to build more Delta printers. As it's just mesmerizing to see them print. I love watching the print come to reality because it such beautiful piece of engineering!

Thanks for answering the question! I expect that people may edit this answer a bit; Stack Exchange tries to keep "fluff" to a minimum and focus on the technology itself. (BTW if people make edits that you disagree with, you can roll them back). You may want to edit it yourself, to show/explain how some of the modifications were made. The site is all about creating content that is directly useful. And I believe the things you explained me earlier, are directly useful for people with Kossels or other delta printers.

Do you have an answer for this How long are the carbon fibre rods for a Travelling Kossel?


text:
Prusa i3 Dual Extruder Setup Issues
I have a Folgertech Prusa i3, on a Ramps 1.4 with Marlin and I use Repetier-Host to control it. I am attempting to convert it to a dual extruder Bowden setup, and I can't seem to get the second extruder to work, although the first works just fine.
This is my problem:
I am not getting a reading in Repetier-Host for the thermistor of the second extruder. It is at a constant 100C.
When I turn on the cartridge heater for the second extruder in Repetier-Host, the cartridge heater does not heat up.
This is what I have done:
For the second extruder, I connected the wires from the thermistor to the pins for T2 and the wires for the cartridge heater to D9.
I have not updated anything in the Marlin firmware.
In Repetier-Host, I selected that there are two extruders, and a second extruder is indicated under the 'manual controls' tab.
This is what I have double checked:
I confirmed the second thermistor works because it indicates a proper temperature reading when plugging it in both T0 and T1.
I confirmed the second cartridge heater works because it heats up when connected to D10.
I apologize in advance if this is an amateur question, but I can't seem to find an answer anywhere. If somebody could at least point me in the right direction, or let me know if there is something I did not include in my post, I would really appreciate it, and hopefully it would help somebody else coming across a similar problem.
Thanks

i think you would need to recompile the firmware and set #define EXTRUDERS 2 then #define TEMP_SENSOR_1 <type> etc etc. there are plenty of tutorials on the net

It sounds like you need to modify various settings for the 2nd extruder. They are in Marlin, mainly in Configuration.h and pins.h. It's a bit of a pain since there are many #ifdef switches for different boards, printers, etc. Be sure you keep spare copies as you work. Try to work out just which #defines are getting applied in your situation, or just change all of (for example) the TEMP_SENSOR_1 #defines. It's tedious but doable.

@TextGeek I appreciate the comment, and the direction to examine my firmware. That was indeed where my problem was. I now have it working.

@fukanchik I appreciate the comment, and the direction to examine my firmware. That was indeed where my problem was. I now have it working.

Thanks to the comments, I was able to narrow down the specific issues in the firmware. The firmware version was really out of date, so I recommend finding the latest stable version.
Therefore, I found the latest stable version of Marlin, downloaded it, and created my own edited version. I went line by line in configuration.h and configuration_adv.h, with the old version I had side by side to the newer version, making any and all appropriate changes. Below are the lines I found most important to evaluate when setting up a second extruder.
Make sure the you have the right board selected from boards.h:
#define MOTHERBOARD 34

Make sure the # of extruders is specified:
#define EXTRUDERS 2

Make sure the sensor is active:
#define TEMP_SENSOR_0 6
#define TEMP_SENSOR_1 6
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 6

This should be considered:
#define HEATER_0_MAXTEMP 240
#define HEATER_1_MAXTEMP 240
#define HEATER_2_MAXTEMP 240
#define BED_MAXTEMP 90

Everything under this comment should be looked at:
// Preheat Constants

These would allocate the second extruder for other motors:
#define Z_DUAL_STEPPER_DRIVERS
#define Y_DUAL_STEPPER_DRIVERS
#define DUAL_X_CARRIAGE

I'm sure there are other parameters I may have missed, and these are specific to my Prusa i3, but I hope this helps out anybody else in the future.


text:
Is there any opensource software that controls the RAMPS RepRap board directly from the computer?
I'd like to find an opensource software that communicates directly with the RAMPS board (or any other 3D printer driver) without using the arduino...
It doesn't matter if it runs on Windows or linux as long as it's opensource. Also, I'm not worried about how this communication is done (USB, serial port, parallel port)...
Has anyone ever heard about projects like this?

The key question is not really if there is such software, but rather if such software is possible, or if it would work very well.
While a printer is more than just stepper motors, those are one of the trickiest parts, so it makes sense to look primarily at that.
Back in the old days of personal computing, it was not uncommon to generate stepper motor signals from the CPU of a personal computer, using individually settable bits on either a special purpose interface (that is in fact basically how the head in a floppy drive was typically moved) or borrowing another available interface such as a parallel printer port.
But then two things happened: computers got faster, but more isolated from the world, and operating systems in common use became much more strict in what they permitted.
To move a high resolution stepper at a decent speed, you need to generate either step pulses or winding activation signals at a fairly high rate.  And to accelerate and decelerate a motor under load, you need to finely vary their timing.  Back when I/O ports hung directly off processor buses, and operating systems could not prevent programs from speeding up the system hardware timer in order to run a stepper routine rapidly, this worked to a degree.  But today:

Most PC class processors have little, if any directly coupled I/O - especially by the time you get outside the box.  An interface like USB is great for moving a large amount of data per unit time, but it is absolutely horrible for accomplishing a trivial task with precise, frequent timing - it is a freight train, not a bicycle courier.  Many of the things which let a processor internally operate quickly specifically work by decoupling it from an outside world that often cannot keep up - memory caches, bus exchange units, etc.  If you do find a parallel port today, it is likely to be on the far side of a PCI bus bridge at the least, and have a different low-level interface than a legacy one.
Modern operating systems have a time-slice scheduler which "owns" the CPU(s) and hands out small chunks of processing time to ordinary programs.  These programs typically get to run often enough to appear responsive to the user, but not frequently enough to accurately drive stepper motors.  There are various schemes which have been tried, for example to create a "hard real time" scheduler which owns the processor, and allows a motor control task to register for precisely needed time slices - then, with whatever time is left over a Linux or Windows or similar kernel is allowed to run, and divide up the remaining time among ordinary programs through its scheduling rules.  Of course, such a scheme tends to need to be revised each time the utilized conventional operating system has a new major release.

While there are ways around these issues, they tend to require atypical hardware and deep changes to the operating system installation - making them neither inexpensive nor easy to setup for end users.
Instead, it is generally simpler and more cost effective (not even $10 these days) to put an embedded processor on an external circuit board, and have it act as a delegate to execute precise-timing tasks on behalf of the host processor.  Somewhat extending from the idea of industrial CNC machines that originally read punched paper tape, and were later updated with a scheme where an ordinary computer "drip feeds" G-code commands over a serial port, modern 3D Printers tend to deliver G-code (or other) command data a little bit in advance of when it is needed, so that the latency of a USB or serial connection doesn't really matter.  Normally enough data is buffered on the printer for it to keep running, but even if not it would only pause briefly between the complete moves which are transmitted, not experience motor stuttering as it would if the USB were trying to deliver each individual step pulse.
As for why an Arduino - probably mostly the history of who built the machines which kicked off the enthusiast printing trend.  If someone from an industrial background were tasked with building something like an FDM printer or a machine with similar motion needs in isolation today, chances are they would end up with an ARM processor that would be a bit faster, more flexible, and with more resources, and likely cost a little less.  But in actual history, the early affordable machines were built by those in maker community, who were already familiar with the availability of the Arduino, and willing to put some cleverness into getting good motion out of its limitations.  RAMPS in particular seems designed to be a coarse-pitch through-hole bridge that a hobbyist could build themselves, and then buy the slightly trickier to work with surface mount processor and motor drive chips preassembled in the form of an Arduino Mega and stepper drive modules.  That even fairly propriety machines maintain these basic parts choices is probably an indication of the utility of not "reinventing the wheel" - if you want to develop a printer, you can start from available components and customize them only one by one as you choose, rather than not being able to run your development prototype until you get a working circuit board designed and fabbed, a working software base developed, etc.

No, there exists no software like that. You can't communicate with a RAMPs board because a RAMPs board has no logic built-in; it's just a dumb breakout board that connects the Arduino Mega to your printer's components (such as stepper drivers, MOSFETs for controlling heaters, endstops,...).
If you wanted to connect a RAMPs board "directly" to your computer, you'd need a way for your computer to generate the pulses that the Arduino normally generates. You could potentially use a parallel port for this but you'd need many more outputs than a single parallel port can provide and you'd need to find a way to do the analog to digital conversion needed for the thermistors.
It's just not very feasible (considering how few computers have parallel ports nowadays).


text:
Pushing Text into surface - Google Sketchup
In Google Sketchup, I have text on a surface that I'd like to push / pull so that the text is etched into, rather than placed upon the surface.  I can't seem to figure this out, the text disappears when I try to push it into the surface and I'm not quite sure what else to try.  Any advice?

Have you tried ungrouping the text? It's created as a group, and groups will not intersect/merge with any geometry outside the group.

I'm voting to close this question as off-topic because it belongs in Graphic Design. The option is not available when specifying Off-Topic...

Definitely you have to perform substract operation.
Take a look here
Extrude text and then substract it from the object to etch in.


text:
What does it mean for step and dir "to be on their own ports"?
The wiki page for the RAMBo board mentions:

Step and Direction pins are on their own ports for synchronous movement capability

What does this mean, and how does it affect printing? Do I need special firmware to take advantage of this?

A "port" for the AVR microcontroller is a set of eight IO pins that are controlled together at a hardware level. The underlying machine code can write an entire byte to set the status of all 8 pins at once. So in principle, all the step pins on the RAMBO board can be triggered exactly simultaneously.
The Arduino IDE hides this behavior from firmwares by abstracting the port's byte handling as a function call for each individual pin. That means programmers only have to know the Arduino PIN number, not which port and position on the processor is being used. And then the modern firmwares typically used by RAMBO do a further layer of abstraction to make it easy for the same firmware to be used by different boards, by changing pin assigned names in a config file (usually pins.h) and not assuming any specific port selection was made during board design.
There's no guarantee for open-source firmware that a particular pin selection was made in hardware. Lots of 3D printer controller boards even have pretty dumb pin assignments, like using hardware-PWM-capable pins for stepper signals rather than PWM'd heaters. Marlin and Repetier have chosen flexibility over performance optimization in this regard. They pretty much let the board designer use any pin for anything. When they have to do stuff like run heater PWM control or fire a bunch of step pulses as fast as possible, they emulate that in software rather than taking advantage of specific hardware that isn't always available.
In this specific case, there may not actually be all that much performance gain/loss. Writing to an output pin is pretty fast. The amount of time difference between firing a few step pulses in sync or firing them sequentially is on the order of a few microseconds. That won't make any difference to the motion fidelity of the printer's physical drivetrains. Somebody involved in the RAMBO design just thought it could be useful, and put a reference to it on the Wiki page (in the very first upload!) and it's never been clarified or removed from the Wiki page in the years since.

Right, so since Marlin writes the pins sequentially, it makes no difference at all? Or do the ports have limited "refresh rate" so-to-speak, perhaps making it more likely that writes in quick succession appear at the same time? I think the last bit about "a few milliseconds" is inaccurate since step rates tend to be in the 10kHz range.

Oh yeah, I meant microseconds, not milliseconds. I'll fix that.

In order for the pins to write simultaneously from a series of sequential commands in the human-readable code, the compiler would have to be optimizing the pin write commands together. I doubt it does that, since Bresenham's has to decide whether to pulse each stepper in a particular interrupt tick... that kind of conditional is not really something susceptible to compile time optimization. Hypothetically, I suppose it's possible, but I doubt the Arduino IDE would be able to do it.


text:
Print contaminated by chips of previous filament colors
I have a flashforge creator dual.
From time to time while printing a model I notice when there are abrupt changes in direction, that a few "Grains" of old filament fall out from the head.  Generally they end up embedded in the print which is not a big deal, but sometimes they get into a visible portion.
I can mitigate this somewhat by disassembling down to the gears, and blowing out all of the old filament.
My question is two fold
"What is causing these chips to accumulate near the gears?"
"Is there something I can do to resolve this issue?"

My bet is your extruder knurls are scratching the filament. If it happens for specific filament then probably it doesn't keep its diameter. It means you can avoid these grains by using better filament.
If it happens always then you could do 3 things

reduce stress on the spring which pushes filament to extruder gear
make extruder gear less sharp
eventually change the great itself


text:
Ball valve to be prototyped
Hey so theres a product we have been prototyping.
We cant do FDM. The item has a ball valve.
and the ball ~ 1.6-1.9mm
I cant seem to prototype it. I have tried SLS, SLA, Polyjet.
Anybody knows what could be wrong, or what should be the dimension i should be using?
I thought I would post this at engineering section, but since I have to prototype I thought its best if its in 3D Printing section
Edit:

Update:

So heres a figure showing the direction of air flow.
Update:
Thanks both answers are helpful. though not a precise answer. Then again, there is no correct answer.
Thanks a bunch. Lets see how the coming months are. :p

It would be helpful if you would provide what aspect of each of the methods was unacceptable. For example, is the problem with FDM that the part is out of dimension? I think that's unlikely, more likely that supports would be needed that FDM does not do well. If you've tried SLA, which provides "automatic" support, was there a problem with residual powder? What went wrong or is expected to be wrong with the various methods?

The precision required in the ball for a ball valve to properly seal is greater than can be achieved with 3D printing. Do you need it to seal properly, or do you just want to verify the fit or something?

It would be great if i could have it with the proto. Or else I will have to keep a finger all the time i press a container. its basically a one way valve for air. If i press the valve closes, and when i leave air is allowed to let in.
We have not really designed a valve like that before, so the bigger concern would be that we get the design right for manufacturing.

Why can't you seem to prototype it? You're asking us what could be wrong, but there's no description of the problem anywhere. How are we supposed to know what's wrong without even seeing the model file, or one of the resulting prints (and why that print is "bad").

Hey, so its a 2mm ball. and its supposed to act like a check/one way valve.
in theory it works, FDM parts are too small or fragile. I tried SLA, but the ridges did not come in SLA. Polyjet the support material is a problem.
My question is what should be the appropriate dimensions to get a ball valve working for such a setting(image shared above)

Frankly, apart from cutting edge "cost is no concern" settings, any realistic item like this would be designed with the intended manufacturing process every bit as much in mind as the functionality.  If you 3d print a prototype, you are basically adding the constraints of yet another manufacturing process on top of the original constraints of machining or injecting molding.   Think about how the part would be injection molded, or see if you can design a version that can be easily machined by hand.  Or maybe you can use a small syringe as an insert in a crudely approximated housing.

Hey why to make it soooo sophisticated and poor?
Air valve cannot be designed with 2 stiff elements - it will never work.
Make the air your friend but not the enemy. Use old good rubber (silicone) "flake" instead. Especially when you have such small design.
Take a look on the picture.

Here you have black element which is rubber or silicone. It's sticked on one side. When air goes from the pipe (goes up) then rubber is slack so the air can flow. When you suck then rubber seals the pipe.
[edit]
You can find such solution in for example bike pumps, inflatable matterss pumps also gas masks and so on. It's pretty fine for low pressure.
Of course ball valves are also widely use but then such device has to have "rubber" ball nest so ball lies on the rubber ring to seal it. There has to be a spring to tight the ball to the ring. Without such spring turning the device upside down would cause the valve would not work at all.
Ball solutions are intended to higher pressure.
Please note the spring which tights a ball creates kinda threshold on the pressure level which means that pressure has to exceed a spring force to reduce a pressure. This doesn't occure in rubber valve.
I don't know what device you are trying to prototype but I'm pretty sure a rubber valve will be just fine.
Please also note that sealing surface is very low in ball valve solution but in rubber valve it can be almost unlimited so it can seal quite well even when the surface is not perfect.

The air passage would be opposite for me.
So i am guessing the silicone pad will be on the bottom.
It does seem like a nice workaround.
Any products which uses these?

Pretty sure water "floaties" use this design.

@albseb see edit in my answer

@tbm0115 I would say that ball or cone is more often used with water devices than flap valve as the water is denser and it's easier to seal it with such valves. A pressure of water column is also higher helping to seal the valve.

As mentioned above in the comments, this really isn't a good application of 3D Printing. At least, not with expectation that it functions. I'd suggest using 3D printing to verify other dimensions and having the part machined traditionally. That ball and "seal" needs to be precision ground or honed to fit in order to stop air flow.
My company has manufactured parts similar to this and the way to go was to produce a concave "cup" for the ball to settle into and hone the edges with a diamond slush using a ball end mill. That way, the ball settles into the cup and the pressure creates the seal.
Omitted due to update in OP's imageUpdate
Excuse the poor SketchUp drawing, but this might help explain a potential design change:
Deprecated image

Please see DarthPixel's answer for a good design choice.

Oh thanks. Good to know its not possible, so i dont need to spend more time looking for.
Any suggestions on the design. Yea i know it has to be a cup.
Its supposed to be made in Injection molding.
How would it be assembled in production?

I wouldn't say it's not possible, but more not plausible with the current technology. As far as suggestions, you might consider creating a removable cover on the backside where the precision ball is and add a rubber washer to ensure an air-tight seal when you screw the cover on. This allows you to insert/replace the precision ball. However this may add some undesired complexity to the assembly of the part. It all depends on how you balance the complexity of manufacturing vs intended use.

so you see the rectangle thing on the part. I was thinking of producing that separately and after pushing the ball in from the top i could close it with the rectangular slab.
However where I see the problem is I wont be able to put a cup shape design.

Please see my updated answer for what I had in mind. Keep in mind that there are many different ways to go about doing this, and it depends a lot on the purpose of the part and intent on manufacturing process.

This makes sense, except i wont be able to use any of the screws os seals.
Its okay if it leaks a bit, as long as reduced air flow.
I have updated an image showing the direction of airflow.


text:
Preview 3d printing process
Is there any type of software in which you can animate the way the .stl object will be printed?
I'm not talking about what the end result looks like. I'm talking about a tool which acts like it's printing the given object as an animation.
I know it somehow depends on your printer but is there anything I can use?

You may wish to consider Craftware for your purposes. It's a free program in beta form that does provide a tool-path animation for printing the layers. It is not so much specific to a printer as it is configurable for your own requirements. The video shows what I believe you are seeking at about the two minute point.
Simplify3D also provides such information, but is not a free program.

The open source slicing engine, Slic3r, also allow for such a preview. The preview is not animated, but you can see the path that your printer will follow for each layer.
To do this, simply upload a model and press the preview button in the lower part of your screen. To select which layer to preview, use the slider on the right of the preview window.

I'm using MatterControl and it has such visualization. User can see synchronized animation which shows how the object is actually printed and user is able to see each path of filament put onto the layer.
It's possible to control starting and ending position so it's possible to precisely visualize each milimiter of filament even between start and end point.
MatterControl also visualizes extrude flow so if user set extrude to 150% or 200% then application shows wider "line".
All of it can be seen in 2D (from top view) and in 3D (perspective view).
There is also possible to see overlay (by transparency) and print speed (visualized by color).
MatterControl also shows non-printing moves and retraction points and their hight.


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My MakerBot 2 jams after a couple hours of prints
My MakerBot 2 jams after a couple hours of prints. It is a couple months old, and the tip stops extruding after a couple straight hours of prints. I am guessing that there is a design flaw and that the media is melting inside the extruder before the feeding teeth. Does anyone have experience with this?

I noticed that your question has a few answers available and has been open for a while, just curious if any of the available answers was able to help. If not, then what questions do you still have?

I am interested in the outcome as well.  We have a MakerBot Replicator 2X that does the same thing.  After about 20 minutes of running it just starts to air print.  We've tried a number of things and the best success we've had so far was to hang a fan on the side of the frame pointed in at the extruder.  I'm seriously considering an extruder swap out with a 3rd party head.

I dont remember how this was solved.

As you stated, it could be a result of the material beginning to melt before the extruder. Here's a few things to look out for:

Is your extruder temperature appropriate for the material? Typical printing temperatures can range anywhere from 200 - 225 °C for PLA (depending on the supplier). Often, if the extruder is too hot, the material will bubble or over extrude.
Is the material of proper quality? There's a reason MakerBot Industries wants you to use their filament (besides putting their hands in your pocket book), and that is repeatability. They've tested their filament on their hardware and ensured that the material will extrude with regular print settings.
Is the material being stored properly? Sometimes people forget to store PLA in a dry place to avoid absorbing moisture in the filament. If moisture is absorbed, it can perform poorly in the print. Indications of moisture can include a slight steam from the extruder and/or bubbles in the extruded material (similar to overheating).
Are the fans operating correctly? If the fans aren't running or aren't running enough, the filament begins to heat further up the extrusion assembly (closer to the drive gear) which can inhibit extrusion. I know that MakerWare/MakerBot Desktop has been updated lately with more emphasis on controlling fans for active cooling, so make sure that your fan(s) are operating for duration of the print as necessary.

All and all, your filament is getting too hot. If you can't determine the sudden change, consider printing with a lower extruder temperature from now on. However, if you're using MakerBot filament (or similar quality) then I would definitely verify that your machine is calibrated, wires are fully connected, and settings are double checked. If all is as expected, then you should call MakerBot support (since they're closed source now, they technically have an obligation to help you) especially since the machine is so new.

Thank you, but this website does not want me to type thank you. Maybe I should leave no response.

Check if your tapes on your extruder have worn out.
If that is the case,
the heat will travel into the motor. when it pushes the filament through the ambient temperature is greater than the temperature of defrom of PLA (~70 °C). When this happens the filament starts bending inside and clogs inside.
This is one case only. You could hear a small repeated noise, also the motor will be extremely hot.
Edit: Also make sure your fans are running at speed. sometimes due to improper wiring it runs at 30-50 %. just give it a light tap. The speed difference is visually noticeable.


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What is a good book to read about 3D printers?
I've been interested in 3D printing for the past month however, I have noticed that it's sort of a "reserved" topic. Meaning that everyone who talks about it, has already some basic knowledge about the topic. What are some good resources for someone who wants to start learning from zero? My main goal is to acquire enough knowledge in order to build my own 3D printer.

As it stands, I think this question is too broad for the requirements of this site. I understand the state of not knowing what questions to ask, but this site is designed for more specific questions. Perhaps try rewording your question to outline what resources haven't worked for you and what type of information (specifically) can help you start your adventures in 3D printing. Best regards and welcome!

I don't understand the want to close everything that doesn't say what specific printer they are using and what the alloy is of the bolt that is driving the filament.  Answers to this question would not only be beneficial to the original poster but many other new people that find the site as well.  The question is easy enough to answer and I'm sure all of us have a few websites that we check daily for information.

@tjb1 this is a shopping question as there are as many good answers as there are books about the topic.

@Trish This question was asked when the site was only 4 months old and struggling to get started.  The site needed questions then and still needs questions today. What do we gain by closing a 2.5 year old question with 5 answers?

You can learn a lot just by reading the forums.  I'll just list a few that are quite popular...
Reprap Forums - Has a ton of information on DIY printers including build logs and posts dealing with many issues.
Soliforum - Large user base with lots of information. Not sure what it's standing is now that Solidoodle is gone but I'm sure the forum will stick around.
SeeMeCNC - Support forum for SeeMeCNC, has a lot of information for Delta printers and also other printers.
There aren't many books that I know of...Make magazine has done a few issues on 3D printing that you could try to obtain.  I'm not sure what your idea of building a printer is, do you want to design your own or follow someone's instructions and put one together?  Designing one would require some basic hardware and engineering knowledge.
All that said, the best learning experience would be buying a kit and learning as you go.  You'll never read in a book what you will learn from having your own printer.

The resources you have at your fingertips are going to be more up-to-date than anything you'll find in a paper/published book. Use this amazing thing called the internet and read everything you can find. Use Google or your favorite search engine using appropriate terms. I'd suggest, based on your overly broad question, that you use "build your own 3d printer" as a starting point.
You'll find that Instructables is one useful resource as well as MakerShed for additional material. You will find a very large source of helpful information at 3dprintboard.com simply by reading others' posts there and at other forums as well.
There is quite a bit to absorb and understand but with the internet at your fingertips, you won't be lacking for information.

I would recommend Design for 3D Printing: Scanning, Creating, Editing, Remixing, and Making in Three Dimensions by Samuel N. Bernier, Bertier Luyt and Tatiana Reinhard

It has a lot of tips, tricks and examples.
Good for beginners and experienced users.

ADDITIVE MANUFACTURING TECHNOLOGIES
3D Printing, Rapid Prototyping, and
Direct Digital Manufacturing
Springer
I think its a perfect book. A lot of details to all technologies.
*Beware there is math and physics involved.

If you really want to learn about three dimensional printing then "Mastering 3D Printing" by Joan Horvath, published by Apress, would be a good place to start.
It does not provide you the in depth knowledge about all the types of printers or materials but it is good enough to get a newbie like me or you get of the ground.


text:
Can I use a pin header in a breadboard to wire up the z-axis motors in parallel?
Can I use a pin header with the molex on my Nema 17 motors and a bread board to wire up the z-axis motors in series?
Also, do breadboards and pin headers have ratings, the way that wires do?

You could absolutely do that.
Ultimately, the amount of current you can push through a wire/breadboard/connector depends on its resistance: for a given current I, a component with a resistance of R will have a voltage drop of V = I x R across it, resulting in a power dissipation of I^2 x R watts.
I measured the resistance of breadboard traces to be around 7 Ohm/meter (measurement subject to some error, but this is the value I got testing over a 300mm stretch at 0.2A). This is quite high, the wires that came with your stepper motor are probably in the range of 0.1 Ohm/meter. If you had a stepper running at 2A, you'd waste 28W of power in a meter of breadboard rails.
Thankfully you're only going to be dealing with a very short stretch of breadboard (wasting "only" 0.8W for 4 wires over a 3 pin stretch each). It would probably be OK, but it's not ideal. Make sure the connection is good (and keep an eye on it initially) as a bad connection can result in significantly higher resistance and that might generate enough to melt your breadboard and short things out.
A better way of doing this would be to simply solder the wires together, or (if you don't want to permanently connect the steppers) use the pin headers you mentioned, and solder them together directly (for example on a piece of perfboard or perhaps just link them up directly with a few pieces of thick wire).

So you measure resistance to make sure it's not going to catch on fire right?

Is there a more ideal way of doing this?

I added a paragraph on a better way of doing this.

This misses the key concern - it is not the resistance of the length of the contacts in the breadboard that is a potential issue, but rather the small contact area between the breadboard leafs and the header pins.

Nevermind, My board actually has both Z-axis inputs on it.

@ChrisStratton The resistance due to the connection is on the order of 0.1Ohm. Not too great to be of much concern (but neither is the resistance of a short section of the tracks).

No, you are quite mistaken about that - the resistance is not necessarily that small, especially when subjected to higher than designed current!  It is grossly ignorant to model contacts as if they were wires!

This particular breadboard is rated for 2A, so the kinds of currents needed for steppers are definitely within the realm of possibilities for breadboards. I just passed 600mA through a breadboard and only got a voltage drop of 30mV (measuring between two rows of a breadboard joined by a single jumper wire).

Your mistaking is in not modeling contact degradation - sure, it might act nice when new, but breadboard contacts are very poor in contact area and oxide piercing compared to true mating connectors.  Not to mention assuming all breadboards are quality... most are not.


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OctoPi (Octoprint) time lapse quality issues
I'm trying to squeeze a little better quality out of my time lapses generated by OctoPrint.
I'm using the Raspberry Pi Camera Module V2 with a Pi 3. I've already edited the Octopi config to get 720p resolution, but the encoding during time lapse rendering is horrific. Blocky as hell.
Right now the encoding is set up at 5000k.
What am I doing wrong here?

I would say it's not a good group for such question. RaspberryPI group is even better than 3d printing

What does encoding at 5000K mean? Sounds like color temperature to me, which (unlikely) might be one cause of blockyness.

@kamuro 5000k is the bit rate of the encoded video.

being curious: is K a unit I don't know or is some b/s for bits/second missing?

I think the bits/second is missing.

That bitrate is pretty low, which might explain the blockiness (is that a word?).
From YouTube's upload guidelines, you are encoding at the minimum recommended bitrate for standard 720P video. Maybe you should boost to 7500K (7.5 Mbps) and see if that helps.
Also, it appears that Octopi is merely calling ffmpeg locally and returning the video. The encoding that is being used might be resulting in blockiness. If you have access to the raw photos, you could just dump them into a directory on another machine and generate a video using a less-lossy video codec. Of course, this would only work if the photos you are taking are high quality. Assuming that they are, here is a nice resource for producing videos from image sequences in ffmpeg.
Good luck!
P.S. Alternatively, if you prefer a lightweight video tool with a GUI, you could use ImageJ.

There's a new timelapse plugin called octolapse that may help. One of the things I noticed with the default timelapses is that lots of things change from image to image, which results in HUGE amounts of mpeg artifacts as it has to constantly redraw large parts of the screen. With octolapse and it's stabilized images the change from image to image is very minimal... mostly just the new layer. The reduction of how much stuff is moving means the same, or even lower, encoded bitrate produces far superior movies.
Compare this 11.1 MB file from the default timelapse tool:
https://cabbey.smugmug.com/Fun/3D-Printing/i-9DrS42n/A
to this 6.8MB file from octolapse:
https://cabbey.smugmug.com/Fun/3D-Printing/i-p3GvvhH/A
Note that these are the SAME PRINT JOB, as I had both tools recording at the same time.

Excellent comparison! Octolapse clearly produces a far better stable video, thanks for sharing your experience. My camera is positioned on the bed, I wonder if the impact is the same.


text:
Layer delamination
I've printed mostly ABS in the past and encountered delamination between layers many times. I've ensured the following conditions regularly:

Build plate is level
Base of print isn't warped (using ABS slurry)
Prevent air draft. I've added acrylic panels to the sides of the machine and the machine is in a custom cupboard.
Nozzle temperature at about 225C
HBP temperature at about 112C (I live in NW USA, so the ambient temperature is typically fairly cool).
Using MakerBot filament

What are some other variables to consider to help prevent delamination between layers?

Cool environmental conditions are the single biggest contributor to ABS delamination. Delamination or edge/corner cracking is caused by warping stresses when the first layer adhesion is stronger than the interlayer bonding. Or it happens when the heated build plate allows a strong non-warping foundation to be built until the print is too tall to be adequately warmed by the plate. In either case, the corners of the first layer can't lift, so the print cracks elsewhere to relieve the stress.
All ABS warping stress, in turn, is caused by the repeated thermal contraction of the fresh plastic layer at the top of the print. The FDM process sticks hot, expanded plastic onto cool, contracted plastic. When the new layer cools, it tries to contract, but it's stuck to a layer that is already fully cooled/contracted. This generates a large shear stress between the two layers. The accumulation of those shear stresses over many consecutive layers generates a large-scale bending force on the entire print. That's what causes both warping and delamination.

The less the previous layer cools below the glass point of the plastic, the less thermal contraction it experiences before the next layer goes down, and therefore the less warping stress will accumulate as the next layer cools.
Environment temp is the biggest thing you can control:

If your printer's environment is below 35C, you probably shouldn't even bother printing ABS.
A 50C environment is significantly better and will have minimal problems with warping and delamination. This is within the ambient temp ratings of most motors and electronics. Air-cooled extruders can typically extrude ABS reliably up to about 60C ambient, at which point they may be prone to clogging. And don't forget about plastic structural parts in your printer.
Industrial ABS printers with heated build chambers print ABS in a 75-85C environment, with lots of airflow. In terms of cooling regimes, ABS in an 80C chamber acts very similar to PLA in a room-temp environment. No warping, but lots of airflow required for good detail.

Printing ABS at a higher nozzle temperature (say 240-250C) will also improve layer adhesion so delamination is less likely to occur. The same warping stresses will be there, but the layer bonding may be stronger than the internal stresses in the part so it survives printing.

Thank you for the detailed response, I think this response will be helpful for others in the future. Side note, this is more of an issue with printer design, but you have to be careful with machines that have a plastic build plate platform. I had a platform warp above 100F.

I know some could not fit your question but maybe someone will look for all possibilities.
Delamination can be caused by:

filament

humidity
diameter

extruder

pressure (holdfast) - soft filament can be crumpled caused by extensive retraction)
dirty jagger teeth (knurls)
thermistor/wire failure - when it reports temp under ie 170C then extruder doesn't extrude
caret floatage (extruder motor cannot pull filament so it climbs)

general

printing speed
temperature issue

Delamination should not happen when the temperature is correct. As already pointed out, different temperatures between hot and cold layer cause warping, but warping is not delamination. If you print at the correct temperature (higher for bigger pieces, lower for thin columnar pieces), the layers will stick.
This is the procedure to optimise the printing temperature to avoid delamination:
http://www.thingiverse.com/thing:35088
Print the object at increasing temperatures (210-250C, 5C by step) and when cooled try to break it. Pick the temperature (for THAT SPECIFIC filament roll) that gives you the highest strength.

Other test objects such as http://www.thingiverse.com/thing:915435 are meant to test print quality, not strength. For strength and delamination you need the procedure I described above.

wall size and filling are also parameters.
If wall size is too thin delamination is more visible

Hi zaaz, and welcome to SE 3D Printing! Whilst your answer may be technically correct, it is rather terse, and, as such, it has been recommended for deletion, unfortunately. If you could expand it then you may get a more positive response. I would recommend that in addition to reading some highly voted answers to gauge the standard expected, that you take a look at the help section relating to answering questions, in particular [answer], and take the [tour] for more information on how stack exchange works. Thanks :-)


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Why does my PLA filament form a spiral shape and clog my extruder?
I'm using brand new PLA filament and am getting frequent clogs in my extruder.
I've had this problem with 2 different filaments from 2 different vendors.
It will be print just fine, then clog up.  It doesn't ever seem to go more than 5 minutes before clogging. When it clogs, and I pull out the filament, it is always twisted in a spiral (helix) shape like a corkscrew.  I have put a picture of 2 clogs below.
I have tried using temperature of 220 all the way down to 180 in increments of 5 degrees and seem to get the same result.  it prints the base layer GREAT on the 70 degree heated bed.  No warping or peeling off.  However, after a few layers, it clogs up and stops extruding.
I am using an HIC PRUSA I3 printer with a single extruder head.  I've only had the printer for a couple weeks.  It had been printing fine with ABS, but the ABS would peel up from the heated bed, so somebody suggested that I use PLA and hairspray.  Hairspray is AWESOME !!  It sticks really well and removes easily as well (once the bed cools a bit).
Please let me know if you've had the same problem with the extruder just clogging up and twisting the filament into a corkscrew shape.
By the way, pay no attention to the black marks on the green filament below.  That's just me marking every half inch or so with a sharpie marker to see if it's still being extruded.

I think I figured out the problem.  Now, to figure out a solution...
Take a look at the image below.  There is a 1 inch tube that goes from the heat element to the heat sink.  This 1 inch of tubing is REALLY hot and larger than 1.75mm.  So, the filament goes through that tube on its way to the head and gets soft in the tube because the tube is so hot all the way down to the head.  When the filament gets hot, it melts and bends and curls which makes it NOT push itself into the heated tip and out onto whatever I'm printing.
The solution would be to find some way to cool this 1 inch shaft between the heat sink and the heated head so that the filament inside of it won't melt.
Any ideas???

Here is a picture of my heat tip.  Note the shaft has about 1 inch sticking out of the heater.  The top of that (above the white arrow) is inside the heat sink.  But 3/4 inches of it are bare and uncovered.  There is also no teflon tube inside the metal throat.

The shape you get is quite easy to explain. It's the shape of the lowest energy possible in your situation. Simple but it doesn't explain the issue... or does it?
It does. The filament cannot be put into the extruder as it becomes plugged. This leads us to some obvious explanations. You can read this post.
So how is that possible that there is enough room to form such corkscrew? My bet is you don't have teflon pipe inside the extruder heatsink. So filament goes into the heatsink and everything is ok until the heatsink itself warms up to the temperature when filament becomes soft, then there is no enough force to push the filament out of the nozzle so above the nozzle filament bends and forms the shape of the lowest energy as said.
Options to check:

Take your extruder apart. See if there is a teflon pipe. If its length is proper.
Check if cooling fan is working well, if it's pushing air to the heatsing but not sucks from the heatsink.

[edit]
Looking closer to your photos I'm pretty sure you don't have such teflon pipe. Your spiral has flat external (virtual) surface... it looks exactly as it would be pushed into hot pipe with diameter of 4mm.
[edit2]
please take a look on the picture

Either missing PTFE tube, or using parts designed for 3mm filament.

@RyanCarlyle yup... good point.

Nailed it.  No tephlon in tube.  One end of the tube has a metal lip so 3mm won't fit.  Other end has no lip.  Just bare metal tube.   Another problem is of a heat sink does not press up against the heat shield. The screws are too long so it dangles there next to it.  I put 2 nuts on the head end of the screws.  Now the  heat sink is very tight up against the heat shield .   That should keep the screw shaft a little bit cooler.

@Curtis but why there is such long pipe out of the heatsink? Something's not ok. at the hot end of the Hotend :) there should be not more than 2..3mm gap between heater and heatsink. This is a heat barrier. It lowers heat transfer from the heater to the heatsink. Definitely the gap is too wide. Could you show your HE without a cooler fan?

Take a look at the picture above in my posting all parts are labeled. You can see the fan. The bottom of the fan is level with the bottom of the heat sink. The tube goes directly into the sink there.  It's about 1 cm from the heater to the sink. I think the problem is that there's no plastic tube inside of the metal throat leading to the head.  The other  problem was the heat sinks were not tight together I have fixed that and I'm waiting for the new throat parts to arrive that have the plastic tube inside them.

@Curtis  I noticed you did add picture but please take a photo without cooler fan. it would help me to figure out your settings. I'm askig for this as it's hole wrong to have such long heat barrier. Whole thread should be inside heatsink... i suppose heatsink can be mounted upside down :)

@Curtis see edit2 in my answer

I've updated my original post with a couple more images.  I'm away from my printer, but found good pictures online of my exact setup. There is no way to move the tube up higher into the heat sink as it would be in the way of the extruder.  I guess I could shorten the tube by 7/8".  I have ordered replacement tubes that do have Teflon inside them.  Hopefully, that will help.  Bottom line is that HIC has a TERRIBLE design with their extruder/print head assembly.  Incompetent and lazy..  Like an 11 year old kid with random parts hacked it all together.  (which is probably how they designed it)

The distance between heat block and heat sink is too big (3/4 inch, almost 2 cm). In this area your filament is some half melt state, not cooled as in heat sink part, not melted as in heat block part. You should make as small as possible, less then 0.5 cm.
Great source of information about hot ends is video created by Thomas Sanladerer: Build your own 3D Printer: Which hotend to pick!

I've found that this happens on my prints on the first layer when it's a really big layer. If you have the initial fan speed on something really low, and it prints for a long time (ie giant first layer) it will twist up the filament. Thanks for the answers, I was confused too.

Welcome to the Stack! I suggest you take the [tour] and then elaborate if/how changing the product cooling fan speed changed the behavvior. I feel confused how this would affect the print as the heatsink cooling fan should run all the time to prevent overcooking, leaking or clogging the hotend.