text:
Marlin (on RUMBA board) switch extruder fan automatically
I have wired in a new extruder with its own cooling fan and I tried to change the Marlin firmware to switch it on automatically above a specific temperature (50 °C).
I did noting in the Configuration.h
I changed a line in the Configuration_adv.h
from
#define EXTRUDER_0_AUTO_FAN_PIN   -1

to
#define EXTRUDER_0_AUTO_FAN_PIN   8

as described in this article.
But the fan is not starting when I bring the temperature above 50 °C (manually). However it starts if I switch the fan on manually from Repetier.
Am I missing something? How do I control the fan automatically on FAN0 output when the temperature  reached the set limit?

Maybe 8 is not the correct pin to turn on the fan for your board? Which board do you have, and what output is the fan connected to?

I have a Rumba board. The fan is connected to Fan0 and the extruder to Extruder0. If I leave that line with -1 instead of 8 the fan does not even start manually therefore I assume that pin 8 is correct for such output. The issue is that does not start automatically as I said above. Something I have not said is that I am testing heating up the extruder manually (not printing, just heating it).

The auto fan functionality is separate from the manual control, so I don't understand why your setting here should affect the manual control. The primary fan on the Rumba board is on pin 7, and a secondary fan output is on pin 8. Perhaps setting it to 7 will work? You might need to remove the regular FAN_PIN define to make this work.

@TomvanderZanden, sorry you are correct. Even if I set #define EXTRUDER_0_AUTO_FAN_PIN -1, the manual on/off from Repetier works. I tried then to set #define EXTRUDER_0_AUTO_FAN_PIN 7 but I get this error:  #error "You cannot set EXTRUDER_0_AUTO_FAN_PIN equal to FAN_PIN. How do I solve this?

The RUMBA board has two fan outputs. The primary fan output is switched by pin 7, the secondary one by pin 8. The reason your fan is not working when you set #define EXTRUDER_0_AUTO_FAN_PIN 8 is because it's switching the secondary fan. If you switch the wires over to the secondary fan output it will work correctly.
If you do want to use the primary fan output then you can achieve this by setting #define EXTRUDER_0_AUTO_FAN_PIN 7 but you will need to search for the #define FAN 8 in the appropriate pins.h file and change 8 to something else (-1 or 7, for example).
I would recommend the first solution, because you should have a controllable print cooling fan, and an automatic extruder cooling fan.


text:
When leveling hotend always slams into bed?
If the hot-end is at ~0 on the Z axis and I go to level it, as it approaches X = 0 it begins scraping along the bed, then when moving back to probe the center of the bed (after homing X to 0) it will scrape the bed again.
I want to add a glass plate but am worried this aggressive homing will smash the glass. How can I fix it? The printer auto-levels and runs Marlin.

I realised the simplest fix for this shortly after posting the question. In either your slicer or your printer controller (I use octoprint, so I added this there) add to the starting G-code something to lift the head so that it is above the point it is scraping across.
For example, change your starting G-code from something like:
G28 ;Home all axis
G29 ;probe bed

To
G91 ;Set to relative positioning
G0 Z10 ;move head up by 10mm

G28 ;Home all axis
G29 ;probe bed

(obviously remove G29 if you do not have a probe)
10mm should be more than enough to lift by unless you have something seriously wrong, but you can adjust the figure as needed.

Marlin has a Z_RAISE_BETWEEN_PROBINGS setting that allows you to, well, raise the Z-axis before it moves to the next probe point. Increasing this value may solve the issue.
Auto leveling only compensates for skew of the bed, but it doesn't compensate for a non-planar bed. If your bed is bowed (apparently you're not using glass yet, so I assume you have a plain PCB which is quite susceptible to this) and due to this is higher in some spots than others, then the auto leveling may cause the hotend to scrape the high spots of the bed.

It seems its unclear what i was getting at. It levels fine, but the centre of the bed is lower than the left side, so when moving left to home the X when Z=0 (in the centre) it scrapes the bed. Z_RAISE_BETWEEN_PROBINGS doesnt apply when its homing X/Y. Also, no PCB bed, its an aluminium plate.

Yeah, if your bed isn't planar, you're kind of screwed :-( . Best to replace/upgrade to something better.

It is planar, its just angled such that the left side is higher than the right side, but only so slightly as it makes a difference @Z=~0mm

You can always add to the starting code as told in an answer above. Also for the scrapping, you might want to set Z_HOMING_HEIGHT to prevent further damage to the hotend. If the Z axis is below the homing height, on homing x or y will first cause z axis to travel to the homing height and then proceed with homing of x or y axis.

This sounds like exactly the answer you are looking for?

Sounds like you need a different sensor? You have a lot of issues from the sounds of it. Also no code so cannot comment on your settings.
If it always scrapes the bed (sorry but its really unclear what is going on) then lower your sensor a bit.. Best I can give you with the provided info.

It seems its unclear what i was getting at. It levels fine, but the centre of the bed is lower than the left side, so when moving left to home the X when Z=0 (in the centre) it scrapes the bed.

Oh, so it sounds like you need a flatter bed. That said I would just tell simplify3d to raise the first layer height. That also said lowering your hotend calibration sensor by 0.05mm (or more) will have the same effect.

Its not that the bed isn't flat... its just angled such that the left side is higher than the right side, but only so slightly as it makes a difference Z =~0mm

So your bed is flat, but not level.  Can you not level the bed with the adjustment screws?

@JamesTrotter that is the definition of not a flat bed. We are not talking about warped beds. we know it's physically flat, but it is not relatively flat.

@StarWind isnt the point of auto leveling to account for a bed not "relatively flat"?

@JamesTrotter Auto leveling is not part of the question. That said follow ups to my reply should be done in a chat. On my printers auto leveling is an assistance program that tells me hey, Right side is too low! Fix it! I think you are thinking the "leveler" screws the Y axis.. That would not work.. If you lowered one end of the Y axis by moving only one Z motor you would get binding and a very bad night. Also there would be no way to fix the X axis.

@StarWind What? Auto-leveling is mentioned at the end of the question, and i don't get what you mean by "tells me hey, Right side is too low! Fix it! ", because it certainly does not do that. It adjusts the print head at all times along the Z axis so that it is always a constant distance from the bed, isn't that the point of it? It doesn't "screw the Y axis?", i don't even understand what you are attempting to convey with that statement.

You need an offset to protect your XY movements for Z=0 even if the plate is planar or angled; for example my sensor is made for 10mm height from plate but measures 4mm due the plate is aluminum. The nozzle needs to be at least 1mm or 2mm below the sensor level. If I adjust the nozzle at 4mm or more this will be scratch the plate if any level variation on bed exist.
So I set an offset and Z safe movement on Auto homming, adding 3 or 4mm. When I press AutoHome the nozzle rise up to the safety level even if the nozzle is touching the bed.
You don´t need the Z=0 to start printing, when you Use the code G29 the printer will check the predefined test points to get the right Z=0 according the angled plate; if your plate is warped you will need a lot of test points but is much better to change it.

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text:
Simulation tool software for 4D Printing
In 4D printing technology or by means usage of Shape-memory alloy (non-metal, iron based, copper based or NiTi material) for 3D printing.
Is there any software simulation tool which I can use to simulate this material change behavior with respect to time?  For example, when introducing a change in humidity or temperature.
Note: It would be best if the simulation tools targeted automotive parts (power train, cooling system, interior & exterior etc.).

I'm voting to close this question as off-topic because it is asking for recommendations of a simulation tool

I am going to say that this probably is a whole dimension out of scope for this group ;-)
That said this new type of 3d printing is still at the University level. Also 4d is not necessarily 3d printing related at all. All it has to be is self assembling. Like http://www.selfassemblylab.net/4DPrinting.php
Unless you have a connect with MIT. Then you aren't going to be simulating any 4d models.
But if you HAD to do this, then you should write a paper about it and become a researcher. You could get published. You might need a PHD in material science. There might be some simulation in solid works.. but I would say you are mostly on your own and have to develop the models as they simply do not exist, especially outside of academia and stratasys.
That said if you take the "4d" part and use models based on the current understanding of the raw material you would have more success.

Dear StarWind, thank you for your reply. I quite aware that this topic is out of this group scope. But, i am quite desperate to find communities discussing this topic. Well, as you mention

that the resources very limited. I kind want to ask a help from communities or maybe from some of person that may knew or has experience on this field.

and YES, i have to do this :-) Btw, thanks for your advise. If found several keyword how i should proceed..

If there is simulation software for this it is likely proprietary and not being distributed at this point. The materials themselves that are capable of self assembly (4D) are still in experimental development, and this there is not really anything to simulate. A simulation needs the properties of the materials that will be used, but these materials do not exist in mass production, they are still being custom made in labs.

thanks for you reply. i think so too. so in the mean time, i will stuck in solidworks, and Labview. i kinda hoping i can have beta test software from Project Cyborg..

(preface : I originally intent to write this as a comment, but the volume limit reached. In that tone, I'll utilize this answer space writing it..)

to simulate those material change behavior in respect to time?

COMSOL, ANSYS or equivalent ring a bell to be.. as long as you have the material properties (young's modulus, density, thermal transport & expansion properties, color?) right.
Also. depending on your actual implementation resolution (nano-scale production.. macro/mini-lego sized assembly), you may want to adjust the mesh size for the finite element method solver.

software for 4D Printing

If your 4th D refers to time.. then the discussion ends here.
If your 4th D is a space (not time) dimension.. Then you need to convert your 4D geometric object into a 3D shadow (just like generating the normal 2D shadow from a 3D geometric object) 1st to proceed. just like an 3D object (eg cube) can have multiple equivalent 2D form (or shadow). The same applies for 4D to 3D. Once you get the 3D coordinates of the chosen 3D form, you may print it as usual.
Software wise.. mathematica (are used in the some of the example I've seen, others unknown/selfcoded) or equivalent will do.. but the key here is not the software.. it's the visualization algorithm. If you can get the "shadowing" algorithm done right, any 3D/math software will do.
p/s : I didn't expect the materials modelling question coming when I read the title (I really thought this question refers to extra space dimension) .. but yeah.. why not. It's a good postgraduate/research topic to take on. ( :

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text:
Editing arc in Marlin for 3d printing
I'm working on designing a 3d printer with a team. The team is using marlin open source software and I started half way into project trying to make sense of things.
Apparently there is an issue with the wheels moving the print head and it always moves a few mm short in the of the desired position. Can some one tell me which part of the marlin code interprets the G-code file and controls movement? I'm thinking of increasing the distance in the x and y axis to correct this (seemingly) minor problem.

What does "arc" in the title refer to? It seems like you have more of a mechanical problem, because no amount of software compensation is going to fix "a few mm" of backlash. Marlin has no support for backlash compensation, and adding it in is going to be complicated.

Does it always cut off a certain distance, or does the distance vary? If you see a constant error rate per distance moved, it could be possible to adjust some stepper motor movement settings. For instance, if your motors always move 20% too short (20mm for a 100mm move, but only 10mm for a 50mm moved, etc...), you could increase the overall stepper motor movement by 20%.

@TomvanderZanden I mean the movement pattern

@TormodHaugene it is always a fixed distance in both the x and y axis. I was wondering where in the code do I edit stepper motor movement

I'd suggest you change your title to "Adjusting X and Y axis configuration settings in Marlin Firmware" or something similar to more accurately describe your question.  I figure you mentioned "arc" because you know you're translating rotational to linear movement, but my first impression from the title was that you were asking something about moving the print head in an arc.

Since your team is designing a printer, you'll have to do some basic calculations to figure out your x and y axis steps per millimeter and then set them in your firmware.
For a decent primer in the basic idea, this video is a good start.  For another decent getting started summary check this blog post
Also, since you're using Marlin, become very familiar with the Marlin Firmware and how to configure it.  The setting you want to change exists in the configuration.h file.  Documentation is included in the file, but you can find good information here in the Marlin Configuration instructions within the Marlin Firmware Github repo.
I hope this helps!  :-)

Note that this answer is correct IF your issue is in the firmware configuration and not a mechanical problem that is causing you to loose steps or experience significant backlash in both the x and y.  I suspect that's not the case, but if you nail down your steps per mm setting and are still not getting the expected movement, be sure to spend some time to rule out mechanical issues as your root cause.  :-)


text:
How close should the nozzle be to the substrate?
I have my nozzle close to the substrate that I am printing on, so that a piece of paper can just about slide underneath it freely, without catching.
Is this the right way to do it?

Traditionally, using a piece of paper (about 0.004" thick) gets you close to your appropriate standoff. However, if you adjust your layer thickness, your standoff should reflect this. Ideally, you will set your standoff roughly with a piece of paper or other type of shim stock, then "fine-tune" the standoff during a benchmark print.
If I'm remembering correctly, the ideal standoff is 1/2 to 2/3 your desired layer height.

For reference, 0.004" [0.10mm] is great way to communicate dimensions in both English AND Metric systems.  Info shared here for anybody using the metric system to call out layer heights.

This photo isn't exact, but may help
Edit: Whoops! Forgot to include source. This is from the Wanhao User Manual/Build Guide. I can't quite find the webpage at the moment.

Could you maybe add a bit more textual content to your post so it can be indexed by search machines and is accessible to those with screen readers? Also, do you have permission to reproduce this image here? Unless you made it yourself, it is probably copyrighted, and its use would require attribution at best and be illegal at worst.

TomvanderZanden is right, you should at the very least provide a link to where you found the image and I think a bit more context would go the extra mile. However, this is a great illustration of standoff for beginners! +1

Did you manage to locate the link to the reference?

Using a piece of paper won't guarantee you get exactly the "correct" height (because different papers have different thicknesses, and it's hard to determine exactly when it no longer catches on the nozzle) but it gets the bed level and the distance will be close to correct.
You can then further adjust the height by observing the first layer and making adjustments based on whether you see the first layer being squished down enough or too much. The babystepping feature (if enabled) is very useful for this.

If I may, I'll recommend heartily joining (or peeking at) the Reprap  group on Facebook.  They have a bunch of 'help' files there, including one on how to level the bed. In particular, it suggests doing the final height setting and levelling at the intended operating temperature so as to avoid any thermal expansion "surprises."
One inherent problem is that the stock limit switches are terrible for position repeatability. Well, not 'terrible,' but enough slop that the first layer or two may be a bit too close to the bed in some circumstances. I'd recommend at the least making sure the Z-stop is locked down good and tight once set, and then if you want to get more precise, look into other proximity or opto-sensors. I haven't done that yet so don't have any specific recommendations.

Though this is useful leveling advice, this doesn't really address the question.

@TomvanderZanden if you read the "z-axis adjustment" and "bed levelling" help files at that link,you'll see the OP's question is dealt with pretty exhaustively.

@Carl_Witthoft in that case it would be good if you included the main point of the answer here. While it's good to back up an answer with references and further reading material, an answer that depends entirely on external resources can become obsolete if the linked material changes or becomes unavailable.


text:
Printed part auto-eject (automatic part removal)
What are the methods to auto eject parts (into a collection area/box/basket) in order for the 3D printer to continue printing?
For some reason this feature isn't common (yet?). Is there a hidden reason why?
Will using the print head to ram the part off the build plate into a basket nearby cause the print head to misalign (if using belts).
I am planning to use a Cartesian XY-Head type (like CoreXY) printer, where the build plate moves along the Z axis and XY axes are on the ceiling of the printer using belts to move the print head.

Asking about the "best" way is likely to result in a lot of opinion based answers.  Consider revising your question to something like "is there an effective method..." or "what methods have been used..."  That way, your question may become a useful reference for future seekers.  :-)

There's a similar question here

While the "best" method is probably unanswerable since it would be based on very specific requirements and subject to change as soon as a better method were devised, here are some feasible methods to auto-eject 3d printed parts.
Some of these are methods that I've considered for my personal use, others have been mentioned by others and added for helpful reference.  Some have been done, others have not (I think), but all of them are feasible.
Scrolling Conveyor-type Bed:

In this concept, parts become dislodged from the print surface as it is deformed around a roller in the process of scrolling to the next position.  Scrolling bed designs must make allowances to prevent parts from lifting up the bed material which becomes an issue especially with warp-prone materials.  Note: This is the basis of the Automated Build Platform (ABP) originally designed (as far as I can tell) by Charles Pax and later covered in several patents by Makerbot Industries.

Deforming Bed:

In this concept, the bed is mechanically deformed when the part removal temperature has been reached.  This deformation dislodges the part which can then be easily swept off of the bed by an arm or similar mechanism.  (As far as I know, this concept has not yet been demonstrated.)

Articulated Segmented Bed:

In this concept, the bed is comprised of several strips. Slightly lowering a portion (let's say half) of the strips would separate them from the part, then slightly raising that portion would separate the part from the remaining strips.  (As far as I know, this concept has not yet been demonstrated.)

Eject and Replace Bed:

This method ejects the entire bed surface along with the finished parts and then receives a fresh print surface for the next print.  This method would likely still require intervention to remove parts from used print surfaces and then return them to the clean stack. (As far as I know, this concept has not yet been demonstrated.)

Plow:

This method mentioned by Fred_dot_u and AllanL uses a specially designed plow arm to sweep parts off the bed between prints.  This method has been effectively demonstrated in this video by New Valance Robotics Corporation that was mentioned by AllanL (thanks!).

Issues using print head to eject parts:  While this method has been tried, and demonstrated (see below), it has some challenges/drawbacks.

Typical FDM/FFF 3d printers are not designed to apply significant force behind print head movements.  While a printer designed specifically for this purpose could be built, using a typical printer in this way is extremely likely to cause the stepper motors to loose steps and result in loss of position accuracy unless parts separate very easily. (however, position could easily be regained by zeroing via limit switches between prints.)
In addition to skipping steps, mechanical issues such as ratcheting/skipping belts or unwanted frame movement could result from even moderately stuck prints.

Examples of pushing or ramming parts off of bed:
While using various parts of the printer to push parts off of the bed may not be an ideal solution, it may be an adequate solution for specific circumstances.  Here are a few demonstrations of the "ramming" method.

Ramming parts off with frame and moving bed like this.
Ramming part with robust print head like this.
Ramming easy to remove part with print head like this.

Interesting question.  I hope this helps!

Interesting, but "ramming" is better suited to clearing bowling pins off the alley than taking out printed objects of unknown bond strength to the substrate -- and unknown internal stress resistance :-(

I agree, Carl.  Ramming would not be a good general solution and I expect would be poorly suited for anyone (like me) who prints a wide variety of objects and filaments.  That said, it could be an adequate specific solution for a sufficiently narrow set of requirements.  For example, ramming may be perfectly adequate for someone running a hypothetical "stretchlet factory."   In contrast, I believe the first 3 methods are more viable for a broader range of prints, with the "eject and replace bed" method being potentially suitable for any print.

Edited the answer to remove the unintended suggestion that the ramming method was better than the other methods.  :-)

ChrisThompson could you also add the suggestion by @fred_dot_u about the plowing method? That would make your answer a perfect reference for all future users :)

@AllanL Added.  :-)

From the standpoint of a hobbyist user with a mid-range machine, my answer is based on the model release from the build plate. With a heated clean glass plate, my model will almost always release once the plate has cooled. The "almost" aspect means that if you want to use the print head to push the model clear, you will be confronted with a stuck model occasionally.
The amount of force applied by the head may be enough to release a stuck model, but "may be" is not going to be sufficient. Especially with a core-xy system (used by my Emblaser laser engraver), you can either toss a belt or cause a stepper motor skipping. More powerful motors will reduce the skipping possibility, but not the belt jump problem.
You could consider to add one additional motor with a sweep arm, geared in such a manner as to provide the necessary torque, along with a force sensor to register a model stuck so badly as to be impossible to dislodge.
Your g-code would be written to lower the bed to the appropriate location to allow the sweep arm to operate, while the force sensor would be tied into the pause/stop circuit of your controller.
Some controllers already have the ability to manage an additional motor, as some are manufactured to provide for dual extrusion.
If such unattended operation is going to be a requirement, you'd also want some form of aborting a failing or failed print.

do you mean something like this?

That's a well implemented solution, isn't it?

Here's a wild idea.  Since you're planning to have a bed which only moves in the Z-axis, build a roller system which feeds a thin, flexible layer of some material (unobtanium, I fear) to cover the build plate. The feed rollers have a weak spring to provide some tension to keep this layer flat but not overly stretched while building the part.  When the part is done, lower the bed to zero while allowing the roller to retract excess parts of the sheet (rollers on both sides of the build plate will have to do this).  At zero, lock down the rollers and move the bed to some negative Z position, causing the overlay sheet to pop free of the bed and ideally pop the printed parts loose as well.
Hey, it "could" work!

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text:
How are SLS printers able to print multiple colours?
With FFF printers able to manage only a small handful different colours (by using different filaments & extruders), how is it some SLS prints are able to be produced in such a broad range of colours?
Are they sprayed post-production?

SLS printing only produces monochromatic models. I think you are confusing SLS with another technology.

Hi, Crollster. It seems like your question needs an update. I have up it on hold for now. :)

The Z-corp/3D systems printers lay down what is essentially ink in each layer (only around the perimeters) much like an inkjet printer, dying the powder as the parts are made. This means they can make almost any color at any point in the model. The down size is these models are pretty fragile, at least the last ones that I have handled. This can be helped by dipping them in cyanoacrylate and letting them dry.
As pointed out in the comments, this is not an SLS process, but looks very similar. The printer lays down a binder (clear or colored) on each layer, and is why these models are much more fragile than SLS models, which are very strong.
Here is an example of some prints: http://mcad3dprintingandprototyping.blogspot.com/

Z-Corp/3D systems are not SLS (selective laser sintering) printers.

This is true, but does answer about how the prints in the original question are multi-colored, the only part missing is the SLS, but I assume that since the process looks like SLS (powder filled build area) that @Crollster may have thought it was SLS. As far as I am aware there is no other method to make these kind of prints.

I think @Jexoteric has it - I was under the mistaken impression that they were made using the SLS process. Thanks for the clarification!


text:
Slic3r mesh merging
I frequently have to print a range of different parts each with different geometrical features. So far, I generate each part's optimum printing parameters manually. To be able to print such parts more efficiently, I am planning to create a "library" of individual geometries, each with its unique set of optimum printing parameters.
The issue I am facing here is in combining all the different geometrical features when slicing. (The geometrical features are individual STL files of different geometries). Slic3r does not seem to merge the meshes of adjoining or overlapping solids, making the joints between each different STL mechanically weak that can be snapped by hand.
I wonder why such meshing is not possible. I realise that if each solid on the plater is assigned different printing parameters such as layer height or infill pattern/density, merging would not be possible, however if we keep such incompatible parameters constant for all solids, and only vary, say, printing speed and the number of perimeter shells, merging should still be possible.
Is the only way to enable meshing of different STLs into a single solid by modifying the code of the slicer?
Thank you in advance!

Try using Autodesk Meshmixer. You can edit STL and OBJ files live and save changes. Additionally it has a feature where you can arrange parts on a printbed in the software and save the whole bed contents as a stl or gcode file. It can then be imported into a slicer software as any other model output.
The software is free to use.  http://www.meshmixer.com/download.html

If I understand the questions correctly, it asks to nest items in a manner similar to the Russian dolls but with differing shapes. I agree that Meshmixer may give you the best option, as you can specify an origin for each model, then move them to a single point. You would be able to export the model as Eagl3 describes, with air gaps and appropriate spacing. It may take some experimenting within the slicer, examining layers, etc, but the answer above is viable.


text:
I am experiencing some severe under extrusion
I did calibrate the extruder to extrude exactly 50/100 mm and it is fine.
I have replaced the old (prehistorical) extruder that was giving me the problem with a new one.
The issue does not go away. It is severely under extruded.
The nozzle is a 0.4 mm, if I extrude manually the extrusion is nice and clean but when printing its a mess.
I have the following setting in Slic3:

Layer height: 0,16
First layer height: 0,16
Filament diameter: 2,94
Extruder temperature: 184°C
Extrusion multiplier: 1
Fill density: 15%

In Marlin I have the following setting for the extruder:

Steps per unit: 1450 (I use micro steps)
Default acceleration: 3000
Default retract acceleration: 3000
Default Ejerk: 5

How can I solve this problem?

This is a 20 mm cube I stopped after 15 layers!
Here is another 20 mm cube, the dimensions are perfect but is absolutely a mess.

Does your extruder constantly push out filament, just not enough? Or does it just irregularly extrude?

Slic3? Do you mean Slic3r?

See also Test print coming out spongy

Assuming your filament dimension settings are correct and your extruder is correctly calibrated...
Your extruder temperature may be too low.  While 184C can be hot enough, it is very near the bottom of the range for PLA and it appears your filament isn't melting quickly enough to keep up with your other settings.  Your extruder may even be running slightly cooler than you think so your 184C setting may actually be printing at 180C or less.
To solve this:

Raise your extruder temperature. I suggest raising your print temperature to 220 degrees and then gradually lower it until other aspects of your print quality are acceptable (bridging, oozing, etc).
Slow down your print. Slowing down reduces the volume of melted plastic your extruder has to deliver in a given amount of time.  This allows more time for the plastic to melt and allows you to use a lower print temperature

Your filament feed mechanism may be slipping.  Even if you have adequate temperature and perfectly calibrated firmware and print settings, if your filament feed mechanism (the thing that pushes filament into your extruder) is slipping, you will have under-extruded parts.
To solve this:

Make sure you have adequate tension on your filament feed mechanism.  If your feed mechanism is too loose, filament may slip and cause under extrusion.  The part to check is the part the pushes the filament into the rotating hobbed bolt or friction wheel...make sure it applies adequate pressure.  "Adequate pressure" or "adequate tension" will vary depending you your printer's design, but it should be enough to provide a firm grip on the filament.
Verify your feed mechanism is clean.  A hobbed bolt or similar filament drive mechanism that has become clogged or otherwise contaminated may cause filament to slip and under-extrude.
Ensure the end of your filament is not damaged from slipping.  Once your filament has slipped, it may be damaged with a worn spot, a bulge, or some other defect that can prevent proper feeding even after you fix the root cause of your problem.  So, as tbm0115 pointed out, be sure to clip off the damaged end to make sure you have good filament feeding into your extruder.

I hope this helps!

Thanks for the good hints. I will try. I also start suspecting the robbed bolt in the extruder which is quite old.

As a result of under extrusion, the end of the filament may also need to be snipped if the drive gear has dug into the filament.

Good point tbm0115.  And check the hobbed bolt and clean off any filament that has become ground into the grooves.

Updated answer to include the slipping filament issue and solutions...inspired by tbm0115.  Important.

Thanks for the useful hints. I replaced the hobbed bolt which was the main cause of the issue and the problem is now manageable from settings in the slicer. I was lost because I resuscitate a hold printer replacing motherboard, extruder, drivers and firmware. Basically starting from scratch because I was unable to upgrade the firmware on the old Sanguinololu. Even worst I did not have the firmware settings of the old one. So was a bit difficult to understand from where the issues was generated. So far so good.....it was simply the HOBBED BOLT! Thanks

Glad that solved it for you! Another possibility (for future readers), is any setscrew(s) connecting your hobbed bolt, gear, or whatever to the extruder motor shaft. Mine loosened up once and it was (of course) the last thing I thought to check... :(

Looks to me like you have your slicer set to 3mm filament when you're using 1.75mm filament. Confirm that your slicer has its filament setting set to 1.75mm and not 3mm (this obviously assumes you are using 1.75mm filament..)
Failing this:

Test extruder steps/mm
Ensure nozzle diameter is set correctly (usually doesnt make too much difference anyway...)
Ensure extrusion multiplier is set correctly.

The filament is 3 mm. The nozzle is 0,4 mm and as I said in my question the multiplier is 1.

Fair enough. I provided the other things even though you'd already said in case somebody else came to this answer and hadn't checked those.

What plastic are you printing with?

PLA, black, 3 mm

Short addition to the already great answers:
Check whether the gear wheel on your extruder motor axle is spinning with the motor. It can seem to be quite fixed, but when under load the motor is turning nicely but the gear slips on its axle.


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Good sources of filament "sampler" pack?
The local stores have started to stop selling filaments in the smaller 0.5 kg spools, and it's getting harder to maintain an assortment without buying lots of big spools.
I mainly just want a bunch of different colors (red, black, blue, green, etc.), ideally as a bunch of small spool "samples" or like a "sampler pack". -- Even if they're at .25 kg spool sizes... -- I don't want to spend a ton of money on buying and storing a ton of 1.0kg - 2.0kg spools.
I prefer to print in PLA, but ABS is fine.  I can only print 1.75mm filament.
The seller should to be able to ship to western US, and have filament of decent quality that's not going to ruin my printer.
What do you recommend?

Are you close to a Fry's Electronics

I voted to close this question as it asks for a product recommendation, and as such is "too opinion based". This is a very subjective question, and it is not constructive (as answers will have very little, if any objective basis for making their recommendation). Please see the help center for what kinds of question you can ask on this site.

And as demonstrated by @Carl_Witthoft, this question will attract (solely) link-only answers which will become obsolete as products enter and leave the market.

Hi BrainSlugs83! Tom is right, and I will therefore have to close your question. Good luck.

Guess I'm not sure I follow the logic -- most of the 3d printing stuff we discuss at all is going to become obsolete as products enter and leave the market -- it will just take longer to happen. -- Anyway, the answer ended up being useful to me, so I marked it. -- Hope that's alright. :-)

A non-product-specific solution would be to go in with a friend(s) on some -- buy full rolls together, then either pass them around if you're local, or divide up each roll. :)

Amazon, of course.   I found a pack of 20 colors, maybe 50g each or so, 1.75 PLA. (that link is direct to this product).
edit:
Well, dang,  I blinked at that particular item is off the list.  Here are two other multicolor packages currently available (2PM EDT 20 Oct 2016)
one , and  ...    two

Ok, why the downvote?  For that matter, why the downvote on the original without either a comment or a close vote?

My guess is because you linked to a product that is no longer sold and the original post has 2 close votes.

Dunno! -- It wasn't me. -- I upvoted though to counteract. -- I can't see the close votes, but no one has commented on my question either, just down voted it. -- Seems like it should be a very easy question to answer too. -- Though 32' seems awfully short for a printer; it's less than 0.1 kg, so it might be that as well?

I didn't buy directly from the links you provided, but I purchased the products (from other sellers on eBay and Amazon). -- This was really helpful.  Thanks. :-)


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DIY SLA 3d printer for jewelry
Where i can find DIY-project or tutorial for creating SLA printer for making models of jewelry?

This question isn't a good fit for this site, as it calls for link-only answers.  Such answers would inevitably become outdated and obsolete as the linked resource disappears or changes, and summarizing the content of the linked source is impossible given the large scope of the question.

Hmm. I make wrong question. "Prease, give me a link to the good DIY-manual for creating SLA 3d printer."

I have no experience with that directly, but may I humbly suggest googling "diy sla printer" as a starting point?  I did, and the quick search yielded lots of interesting reading.  Good luck.  :-)

Hi, Alexandr! As pointed out by Tom, your question is not a good fit for this site. Please take a look at our help section for an introduction to 3D Printer Stack Exchange.


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First (bottom) layer has gaps
First off - I'm rather new to this and I might be on the wrong track altogether...
I'm printing PLA using a simple DIY XYZ printer with a direct-driven extruder, 0.3 mm nozzle, 0.2 mm layer heights, using Slic3r. I've tried to calibrate the bed as level as I can. I believe the distance to be OK because the skirt prints in straight lines with no wobble.
While the overall results aren't that bad, I'm trying to improve the quality. I'm not happy with the first layer: While it sticks to the bed nicely, the printed strands are too far apart - there's a very noticeable gap between them that I can actually see the second layer through. There appears to be a problem with the second layer as well which always ends up too small (recessed). That's only the second layer, though - from the third layer on, that problem disappears.
What I've tried so far:

change the nozzle and/or bed temperature by 10-20 degrees up or down - no visible change
change the print speed (using the dial on the printer) - no noticeable change, especially when going slower
change the first layer extrusion width from 200% to 250% or 300% - that made the strands "flatter", but also made Slic3r space out the strands so that I ended up with gaps again
increase the extrusion multiplier - that seemed to help the first layer, but lead to over extrusion further up, so I didn't pursue that any further
manually increased the flow setting for the first layer in the printer menu to 135 - that seems to do the trick, but I have to turn the setting back again on the second layer

Now - is this the right way to fix this or am I just patching over an entirely different problem that I just failed to diagnose properly? If it is the right way, how can I tell Slic3r to either change the flow rate / extrusion multiplier just for the first layer or increase the extrusion width without spacing the strands further apart?

You can, in most slicers, set a separate extrusion multiplier for the first layer. This doesn't appear to be possible in slic3r, but there are a couple of ways to work around this:

Change the Z offset (either in software or by adjusting the endstop). Bring the nozzle closer to the bed for the first layer. You can combine this with an increased first layer height. This is the most appropriate fix for your issue.
Use M92 EX.XXX to increase the extruder steps/mm in the start G-code, then set it back to normal in the layer change code. This emulates increasing the extrusion multiplier for the first layer.

I managed to get this issue resolved by adjusting the first layer height and mainly by even more precise manual bed leveling. I've ordered a set of precision feeler gauges to get rid of the paper method - although I'm keeping the rock and scissors, just in case...


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stl files -measuring stl files
I had a problem with my Z limit switch bracket falling just short of the bottom edge of the z stage.
I'm trying to make the bracket thicker so it's pushed more towards the left.
1) how do I measure the thickness of the bracket in the stl
2) HOw would I make it thicker if it is indeed too thin

It's might to be mounted standing up right.
I want to make it thicker x axis (if it's stood up)

If you have the original CAD file this would be far easier to modify and maintain then an STL.
MeshLab also has the capability to measure the view on the screen as well as bounding box measurements. Bounding box measurements should be possible in any pre-processor you use for slicing STL files though.
MeshLab can also be used to scale, merge or translate your STL if desired. however I would also recommend mesh mixer as it is more user-friendly.
The last option if you have any coding experience, an STL file can be easily read and then you could select the desired vertices and measure/move them and then rewrite out the STL file. There are libraries for most major coding languages for dealing with STL files.

Oh really. If I can't edit it normally then I will resort to tinkering in c# .net. I'm a programmer by trade. Albeit not very experienced one but I will give it a go if I have to.

MeashLab works great, it supports all platforms (Mac, Windows, and Linux).

Consider to provide additional information regarding the software you use and the source information of the STL file. I will make some general suggestions that you can implement to resolve your problem.
Meshmixer is a free program that has the ability to measure overall dimensions as well as point-to-point locations within an STL model. Import the STL, select Analysis followed by Dimensions to get the overall information. For point to point, the interface is less intuitive and I would suggest a YouTube search for a tutorial.
Without seeing the part, I cannot suggest a specific sequence. If you are able to visualize the action of stretching the part in a single direction, Meshmixer also allows that:
Select Edit, Transform and note the three-axis tool which will appear in the model. Each arrow has a small box at the end. Grab the appropriate box with your mouse and move in the desired direction. It will stretch/distort the model on all surfaces in the direction you move. There will be a digital reference showing during this process, allowing you to more precisely set the increase in thickness.
If there are holes in the same plane as the bracket you wish to thicken, they will become longer if on the same axis, or they will distort severely as you increase the thickness.
You can use Meshmixer to perform a plane cut to separate the model into individual parts to avoid undesired distortion.
Please provide an image of the model and an indication of the portion you wish to increase.
EDIT after photo and some clarification. Your last line has valuable information. Thicker x axis if it's stood up implies thicker z axis in photo. That's the easiest location for that model. It would take me about 30 seconds to stretch it in Meshmixer. If you attempted it yourself, it might take you two or three minutes.
I agree with the post by "plaintoothpaste" that it would be easier if you had the source file. I use OpenSCAD and adjustments are simply a matter of changing a number in a text file, while other software, for example, SolidWorks requires that you find the parameter and modify it to your requirements.
Because of the shape of the model, the first reference I provided (Dimensions) would give you the thickness and as a bonus, you can change the number in that window to the desired figure. Export the model and you're done. Far simpler than using the transform tool, if not as much fun overall.

Cura will tell you the outer dimensions of a part; I don't think (or know) it can provide each feature's dimensions.


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Slicing software and Sidewall
I am new to FDM RP.  I've done a lot of work on ZCorp and Connex.
The question is can vectors curve drive an extrusion nozzle?  Within a 3D volume I can generate curves that I want the print nozzle to follow. Is this possible or has it been done? If so, what software or is there a hack?
Another question is, can you print a part with no sidewall or containment boundary?

Just for the fun of it and perhaps to contribute to this question, I opened my recent task in Simplify3d slicing software. Setting the perimeter walls and top/bottom surfaces to zero did not generate an error as I expected.
The print preview, essentially a g-code viewer, presented the model as only the honeycomb infill for which it was configured. Having zero layer thickness for the top/bottom also prevented features from printing that were composed of only walls without infill. Small details that otherwise print well were lost completely.
I can see that properly designed models printed with certain infill patterns and percentages would be quite artistic.
With respect to the first question, one could create a program to accomplish the desired result if one were an experienced programmer. It would be a matter of converting a specific set of vectors into g-code for the printer. I'm familiar enough with g-code to know that a well defined curve is easy enough to create in g-code but only if the mechanicals support arcs. If not, it's not so easy. The conversion from a vector format file to g-code would require a talented programmer indeed.
I suspect there are talented programmers "out there," but one must be suitably skilled and equally suitably motivated, yes?

It's not difficult to write software that converts a curve to gcode (break the curve into small lines and emit a G1 command for each line) - however, it's way easier to work with solids since the toolchain supports solid really well and curves not at all.
Just create a solid with your curve as a wall and everything works.
For the second question, no top/bottom works with every slicer I tried (set the top/bottom to 0 layers/height) - Cura seems to support no walls by setting shells to 0 (but I only checked layers view, I didn't try to print).

Vectors do not drive the extrusion nozzles in current software. There are methods to take vectors and create a solid model with them which can be used. The standard workflow is to take a solid model, save it in the STL format, and then import the STL file into the slicing software and outputs Gcode with contain coordinates for the extrusion nozzle to move to.
I have not seen any software that will create just the infill geometry without any bounding surfaces. This would be such a specific use case that it is unlikely to appear in current software. That is not to say that it couldn't be done, but you would likely have to implement such a feature yourself.


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Can I use OctoPi locally?
I am trying to use my M3D printer that doesn't work with my Linux computer. I have been told that OctoPi would make it work.
My current setup is:

Raspberry 2 without WiFi, with OctoPi running
Keyboard and touchscreen connected to the Raspberry
A .obj file located in /home/pi/ on the Raspberry

I don't know anything about OctoPi, but it seems to be created to use as a print server connected by WiFi.
My question is: how can I use it locally, directly on my Raspberry?
NOTE: I can only use my Raspberry in command line for the moment, but if required I can install lightdm to display stuff.

If you install a web browser on the raspberry pi, you can access octoprint from there (by going to localhost). Is this what you're after?

Have you considered maybe using wired Ethernet, the way OctoPrint was originally designed to work, as described by most Octoprint installation guides, skipping the optional WiFi setup -- a, b, c, d, etc. -- instead of WiFi? Normal wired Ethernet cables work fine for me.

To use it locally you need to be able to view the desktop.
sudo raspi-config  to pull up the config menu and enable boot to desktop.
If there is no browser installed already you'll need to install one.
sudo apt-get update
sudo apt-get install epiphany-browser
Open the browser and navigate to http://localhost/
I recommend configuring access control when it prompts you. After you configure it, click login in the top right and login to use octopi.

ALTERNATIVE

octocmd is a command line interface for octoprint. If you would rather not boot into the desktop then this is the way to go.

Thanks for the answer and the alternative. That's exactly what I was looking for.


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PLA use outdoors?
I have been using PLA filament for two years now and have had good prints. ABS on the other hand has not been so good, so my choice of filament is PLA.
I am getting ready to do a sign for the American Legion and the colors are black, blue, and red and are 0.8 mm thin. The black letters are 4" x 2.5", blue are 3" x 2" and the red are 7.75" x 5.5". I plan to treat them with UV protection spray and attach them with clear epoxy to white back lit Plexiglass.
As the letters are quite thin, my question is how well will this hold up in the weather? The sign hangs on a pole that points east & west so the letters will be facing north and south. The original was painted with spray paint and the red paint south side faded to the point you could hardly see it at all. The sign had been there for some time and was done at a professional sign company.

Possible duplicate of 3d printing for outdoor use: what types of filament are most weather resistant?.

Professional != Quality work lol

Desert SW (USA) summer days inside a car can be 150F or more.  PLA is not so good.  I use ABS for outdoor here.

Why does everyone keep mentioning a car?  It's an outdoor sign, it does not matter how hot it gets in your car.  Your car is almost always going to be hotter than the ambient so I fail to see how it's relevant to keep mentioning it.

I'll stuff this here as I don't have a full answer yet but the glass transition of PLA is 60C, if your letters are supported (glued) well then I see don't see them failing even at the glass transition temperature.  I imagine color retention would depend on the supplier and pigment used but I would also have to guess that the same/similar pigments are used in ABS/PLA so they would have similar color retention.

@tjb1 I guess I could have added on the sidewalk or side of a building, or just in direct baking sun for generalized purposes.  I have seen a lot of people print items for a car hence the most common reference.  I have seen an egg fry on a sidewalk and  just yesterday I was at an auction where they left a couple large screen TVs in the sun, by days end the back on the one was warped and curled.

For context:   If you consider paint, ink, etc. red tends to fade worse than other colors outdoors, especially blue, unless the red is specially made for UV resistance.   The reason is the blue reflects most damaging UV but red at the opposite end of the spectrum tends to absorb it.   Also, when I was looking for info on UV resistance of HDPE/UHMW, one site said that the best UV resistance additive was plain old carbon black which is what is typically used to make things black; apparently it soaks up the UV without damage.  However, black parts may get hot and PLA doesn't like heat.

I printed a handle for a rather big rolling door in natural PLA (From Fabberparts) - no UV protection. It's on the weather side of the house and is exposed to direct sun half the day.
And after three years cycling to all the German seasons it's still absolutely fine. Also, Wikipedia told me that PLA has good UV resistance - so you should be fine IMHO.
Here is a good blog post about your question: Using PLA for Long-Term Outdoor Applications.
Update: After ~ 8 Years the door handle ist still fine.

Unfortunately, the original link no longer worked and the blog had been moved, with an updated URL and the URL would not work (for me at least). I tracked down the article and have amended your answer with the correct URL. However, as links tend to invariably die over time, you may wish to consider including and quoting the relevant and salient points from the article, directly in your answer. It would be a shame to lose information from the blog, should their website die some day.

PLA is quite safe even in australia: https://www.youtube.com/watch?v=qqNfa_zExRU

In case the blog post gets ever removed again, I saved it at https://web.archive.org/web/20190708121636/https://www.iepas.ucar.edu/using-pla-for-long-term-outdoor-applications/

Keep in mind that PLA has a much lower temperature point, where is starts getting flexible. I once had PLA-printed parts in my car in the summer for three hours and when I came back, they where bent.
I don't know about the weather conditions in your local environment, but if you experience hot temperatures and your sign is hanging in direct sunlight, I would suggest to make sure you secure the letters against bending (e.g. cover them with a coat of epoxy or something like this).


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How to control 3d printer printing in metal?
I have a question. Home printers are controlled via open-source software such as Pronterface. These printers print mostly in plastic, but how to control the "metal" printer. The principle of the printing here is a little different. Is it possible to use, for example, Pronterface for this task or the completely different software is needed?

Most metal printers run on proprietary software that comes with the printer. Since you haven't specified what specific printer you are trying to control, I'm voting to close this as "too broad".

Hi, Bartosz, and welcome to 3D Printer SE! I completely agree with Tom that your question is too broad in it's current state for you to get any useful answers. I will put it on hold until further edits. Also, I recommend you have a look at our help section for an introduction to Stack Exchange.

Pronterface would control the printer, but you would need a slicer that could give you g-code that works with said metal printer. Being it would be using metal, most of those are powder based, using a laser to sinter. The slicers for FDM based machines would not create the correct g-code for the application. I know there has been some effort around powder based printers (both metal and plastic) but I do not know of any software that has resulted from these efforts.
This wiki index for powder printers may be of some help to find out what software they are working on, most likely a custom solution.
http://reprap.org/wiki/Powder

You seem to be assuming that a metal 3D printer would take G-code at all or could be controlled over serial, which might not necessarily be true. It is better to only attempt to answer questions that are well-posed, and this one isn't (given that the specific printer isn't specified, the answer could be either "yes" or "no").


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Weird bumps cylindrical hole
Not quite sure what's happening here. I printed it as a single ball and had this effect. I thought it might be a cooling issue so I printed 4 at once but the issue still occurred. If I size the ball up, the problem reduces.
Note that the hole is supposed to be a cylinder.

Do you have a gcode viewer that lets you see each layer, retractions, etc.?  You might get a clue from that.  And are the sides of the balls printed normally, or do you see distortion in the side wall under each tiny ball?

Can you post the original STL, and in addition the slicing tool you're using (and any pertinent parameters you set in that tool)?

It looks like possibly a combination of too high of extruder temperature and poor retraction.

First, try reducing your extruder temperature. PLA ideal extruder temps range from about 185C to 225C; depending on purity, quality, and climate. This can help prevent additional oozing and clogging. If your extruder clogs easily, you probably have too high of temperature.
After you've verified you have correct extrusion temperature. Try finding/adjusting retraction settings in your preferred slicing engine. Here's a good troubleshoot page from Simplify3D's website.

The blobs in the picture look very "watery", which indeed indicate a far too high extrusion temperature. I guess the round drop shape comes from a z-lift movement on retraction, which is usually very useful to avoid nozzle collision during travel moves. On a side note: using a too low nozzle temperature can also cause clogs. If you have no idea where to start, I would try 205-210C for typical PLA, and take it from there.

In order to exclude a cooling issue, you could try printing a larger object alongside the spheres. Something that has a constant cross-section and is at least as high as the spheres.
I have had issues when printing objects with a sharp tip, even printing 8 at once the total amount printed on the top layers was not enough to let the material cool before the next layer.

It looks like it is trying to fill in what might be small gaps and is putting blobs down because the gaps to too small of a detail to accurately fill.

This is quite short for an answer, and it doesn't do what an answer is supposed to do: how would you solve this problem. Change the design? Slicer settings?

@TomvanderZanden it doesn't look like the OP specified their slicing engine. So, it might be a bit premature to suggest slicing settings.


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Print fails at perpendicular boundaries
I recently changed the printhead on my DeltaMaker from stock to an E3D Lite6, and am struggling to get back to my original quality, reliability, and repeatability.  I thought I had gotten the recipe pretty close to dialed in and tried a bigger print last night.  It turned out pretty good in most respects except for where vertical structures rise up from the horizontal surface (and a retraction/stringing issue that I didn't think was but perhaps could be related).
The screw hole mounts seem well-designed to me:

No 90 degree transitions - I would think this would be the least of my problems.  But last night they had serious problems:

I haven't seen a problem like that before.  Extrusion rate seems basically perfect - why does it look like it just stopped extruding around the perimeters?
I'm using PLA filament and Simplify3D 3.1.0 slicing.  Settings:

0.35 mm nozzle, 0.40 mm extrusion width, 1.05 extrusion multiplier
0.15 mm layer height, 3 top, 3 bottom layers, 2 perimeter shells (maybe should try 3?)
30% infill, 60% outline overlap, 110% infill extrusion width
Temp is 220°C (thermocouple wedged between nozzle and heater block reports about 206°C when thermistor says 220°C)
Print speed is 2700 mm/min (45 mm/s)

Has anyone seen this issue before?
UPDATE:
Increasing outline overlap from 60% to 90% almost fixes the problem (at least visually if not structurally) - there's just one small hole at the base of each structure.  (I stopped the print a few layers after the problem layers do ignore the tops.)

Going to 99% (Simplify3D's max) would probably get rid of those last holes but I have to think that maxing out S3D's outline overlap setting to just barely make the print work means I haven't found or addressed the true root cause...

Since you said you don't have a cooling fan, try lowering the temperature on your print head to something like 205. The strings in the first and second picture also occur more often when the print temperature is too high as well.
The layer time gets really small at that transition, so make sure the print speed is slowing down while printing that part of the object and pausing in between those layers to allow for cooling.
It looks like the plastic is still molten and is being dragged around too me.

It looks like the first layers that are making the vertical transition do not have enough to stick to and are curling up. Are you using a cooling fan?

Hi welcome to the site! I see you've been quite active answering questions, but this isn't really an answer to the question, and would be more suited as a comment (you will be able to leave comments once you have 50 reputation). This answer is quite short, and skips over a lot of potential solutions. Please see the help center on how to write a good answer.

@Jexoteric - No fan for the print, but that hasn't been a problem historically with this printer (maybe that changed with the new hot end?), and I can't understand why it would only fail to attach at the relatively mild sloping part when it's so solid on pure horizontal or pure vertical surfaces...

Is the tip of the extruder a significantly different size, such that it could flatten the trace width more or less than it could previously?

Nope - old and new nozzles were both 0.35mm.


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How should I power these stepper motors
I am rebuilding my printer, a hold Prusa/Mendel that has been boxed for years. I have changed the board ( I am using a Rumba) and the drivers (I am using Pololu 8225) with heatsinks and 1/16 microsteps.
5 motors type 42BYGHW811, rated: 2,5 A, R 1,25 Ohm.
I have set the stepper voltage at 0,8 V for XYE which gives a current of 0,64 A and they seems to work without problems.
To get the same current on Z, where I have 2 motors in parallel, I should set it at 0,4 V but the motors do not turn at such low voltage. They just make noise, no turn. I have M8 rods nicely lubricated on such axis and I can turn them easily by fingers. If I go up to 1 V the motors turns but then the driver gets very hot and I loose steps. May be I should play with the acceleration too?
I am not sure if the above settings are correct. Your hints from your actual settings and experiences will be appreciated.

If the motors are in parallel, then setting it at 0.4V means each motor will only get a quarter of the current a single motor would get at 0.8V. If you set it to 0.8V each motor will get half. I think 0.8V (same as for the other motors) would be an appropriate setting. Stepper drivers are constant-current, not constant-voltage.
Are the steps/mm for your Z-axis correct? Perhaps it's just trying to move too quickly.

Thank you Tom. Happens when you are focusing on a problem on your own that the big picture is invisible. The issue was in the acceleration, I reduced it from the default 3000 to 1000 and the same also for the feed rate from 5 to 3 and it is now working fine. The stepper voltage is at 0,8 as per the others.


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Printrbot going off axis when initializing
I have a strange problem with my Printrbot Simple Metal.
When I start printing it's suddenly trying to go off axis before starting to print. All is fine once it actually starts to print, but it's very annoying to hear the sound on the start and end of each print.
That can't be good on the motors and chains either, something is going to give out at some point.
Here's what that sounds like: YouTube - IMG 5600.
My OctoPi settings are:

It is very common that FDM 3D printers "home" their position at the start of each print (as defined by the slicers preprint g-code). This is done by deliberately running the end effector towards its expected X=0, Y=0 position until it hits the endstop switches for each axis. Could it be this behaviour you are seeing? If so, I would suggest checking that your endstops are functioning correctly.
You can manually activate this homing action using the G-code G28 in (for instance) Pronterface. Alternatively, you can verify that your endstops are actually working using the M119-command while pressing each switch manually.

Could the axis get inverted somehow? Because instead of taking it all the way to the stop, it's taking it in the opposite direction when it starts?

Just found something. I was reconfiguring the Z leveling, and it's changed the behavior a bit. Now the X axis is doing the screeching, even though it's not gone off chart?

If you axes are going reveresed, the that certainly is something you should fix! :-) However, when you say "screeching", do you still mean the sound in the video, or just a high-pitched sound from when the motors are powered and standing still? In general, as long as stepper motors are powered (that is, they resist movement if you try to move them manually), they will often make a high pitched noise. You can try to run M18 to disable all stepper motors, and see it that helps.

No, this is the sound in the video, excuse my english. How would you call that sound? I tested the endstops, and as mentioned they work. Any other ideas on how to fix the issue?

@R0b0tn1k, did you figure out if it happens as part og the G28 homing command? Watching the video over again, it really looks like the endstop for the bed isn't cutting the stepper drive, so that it continues to force the bed outside it's limits. I'm guessing what you are hearing is the stepper motor or some gear constantly skipping as a result.

It's definitely a part of the homing command..

However, I pressed the triggers manually, and they work. So i'm at a loss as to why this happens. If the triggers dont trigger, then the horrible sound would continue forever. So it does hit that stop at some point?!?

I'm thinking it's trying to go outside of the configured build bed (150x150x150). Actually, i'm not sure at this point. If it were to go outside of 150, the trigger would trigger? :)

If working correctly, the triggers should absolutely prevent the printer from going beyond the physical bed limits. :-) This is also what it tries to do when homing the bed, but the motors should stop immediately after hitting the triggers. Could it be that the carriages don't hit the endstops correctly? The reason why is stops after a while is because it will be ordered to move to some point beyond its limits when homing, but it is never actually expected to reach that point as it should trigger the endstops first. ;-) Side question, could a software lag be the issue?

How do I check for software lag? This did not happen before I went on vacation. After I came back it went crazy...

Btw, whole thing is working on OctoPi

Ok, I seem to be noticing a bit of lag in Octopi when I press certain commands. Any cure?

@R0b0tn1k lag can come physically and digitally. Physical lag (although unlikely) can come from excessively long cables (USB, RJ45, etc). Digital lag can come from a number of sources. Double check that you have the minimum set of applications running in the background. Try to free up CPU and RAM usage as much as possible. Are you running true OctoPi or just OctoPrint on a PC?


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How to map Cura printspace to Prusa I3 printspace
I seem to be observing a couple problems w/ Cura2.3 OSX . It seems to be placing the sliced data (gcode) over to negative X by a cm or so.  Further, the X- and Y-axes displayed in Cura definitely map to Y and X when the printer starts up. I've verified that I have the printer's X and Y end stops and motors connected to the correct outputs. Now, I can just rotate my parts before slicing, but I'd rather have things be "correct" to begin with.
I've read the relevant info at question 1323, but I'd rather if possible adjust the Printer Settings for my defined printer in the Cura Preferences sub-menu. I couldn't find any description of what the "printer head" X and Y offset values mean there, nor what the "Z-gantry" value does either.
I'm running from the SD card; no USB connection.

Carl, not sure if it would help, but this ultimaker thread seems to have lots of relevant discussion.  Maybe some tidbit there will help.

@ChrisThompson Thanks, I suspected commanding an offset might be what's needed.  I'll hit the Home command on my LCD interface and see where the extruder nozzle sits.

When you figure it out, you should answer your own question...I think it would add value.  :-)

Well, in my particular case, it helps to have the X and Y control (motor and endstop switch) plugged in to the correct ports :-( .  That took care of the X vs. Y orientation problem.
If you command "Home All" either via the LCD panel or over USB, the nozzle should sit in the front left corner of the bed as you face the machine ("stage right" for you thespians).
The link Chris T provided, ultimaker, provides helpful background information as well.
Next, if there are small offsets, find control can be set with a script similar to the following (leave out the auto-levelling command if you don't have that),
from printerbot talk forum .
M104 S{print_temperature}
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
M109 S{print_temperature} ;wait on temperature line
G29 ; Auto bed levelling
;G28 X0 Y0 ;move X/Y to min endstops
G92 X132.4 Y20; Reset actual position after G29 bug
G92 E0 ;zero the extruded length
G1 F{travel_speed}

And finally, there's a calibration file at thingiverse which prints large squares so you can see the exact offset.  I hope to get that file modded with a couple markers (indents, e.g.) to verify orientation as well as location.


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How to add tolerances/gaps in Autodesk 123D Design?
When I design parts that must fit in each other, I usually keep in mind that prints are 0.2-0.5 mm wider than expected (depending on the material), and I size the parts accordingly.
However, sometimes, I design the whole part and then slice it with planes or lines. In these cases, I need to push/pull each contact surface manually by the same amount (0.2-0.5 mm), which is a time-consuming task. Another option is to use a cutter to remove the outer surface layer (basically, I remove the rigged surface, making it smooth again). Still, it's unsafe and even more time-consuming.
How can I quickly generate said controlled gaps on the contact surfaces between two objects but not on the rest of the object? To make it everywhere, I could use shells, I guess, but I don't need that on the whole object.

This isn't an answer exactly, but I'd suggest you skip 123d design and check out Fusion 360.  It's easy to use, much more capable, and very well supported by tutorial videos.  The way I normally handle tolerances is to add them as parameters that I use in my sketches.  The sketches define the 3d geometry.  If I decide I need more clearance later, I just change the tolerance parameter and it all updates automatically...that's the power of good parametric CAD.

I think fusion 360 is not free... Unless I lie and I say I'm a student.

No need to lie, use the free startup license.  Autodesk has been offering this for a couple years now.  This lets you legitimately use it for hobby, fun, or even business as long as you're not using it for a business that makes over $100,000 per year.  See here and feel free to confirm with Autodesk. (I'm paying for my license just to maintain my access to Fusion 360 Ultimate, but really Ultimate doesn't offer much more yet.)

Unfortunately, 123D Design doesn't have such a feature.
You could select multiple surfaces and push/pull them all at the same time though.
Remember, your 3D Printer's slicer should have an option to undersize or oversize holes and walls, to help reduce/remove the effect you talk about.
It's called size correction, I think? Simplify3D Has it, atleast.
You might have to tweak this for every filament type, though.

AFAICT Push/Pull faces is the closest thing to what you're looking for. eg:

In OnShape there is an "offset face" command that allows applying such an offset to multiple faces at once: How to add tolerances/gaps in OnShape?
Unfortunately I'm not aware of a way to do exactly the same thing in 123D Design, but I'm far less proficient with that tool (as Alucard Pawpad noted, though, it is possible to just select multiple faces at the same time and manipulate them all together, which is somewhat similar)

So that's what I was already doing. In the meantime, I switched to Fusion, 123D is no more available. It works the same way, but with the history I can always change that amount later on, which is a bonus.


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What are the downsides and aftereffects of using a smaller nozzle?
A lot of consumer desktop FDM printers come with a 0.4 mm nozzle. I'm looking to print fine details objects and I was considering trying to use a smaller size nozzle. But before I do so I would like to establish a list of downsides and unwanted consequences.

Here are some things to look out for when switching to a smaller nozzle size:

Curling (out of the nozzle): Make sure the nozzle is clear of any debris to avoid the extruded filament from catching and therefore curling around the nozzle.
Warping: You might experience more warping on the build plate and delamination between layers as a result of the smaller surface area of the layers.
Reduce speeds: You should reduce your print speeds anyways when printing fine-detail objects. However, the smaller nozzle size will need a bit more time to adhere to other objects (see above).
Standoff distance: The distance between the nozzle and build plate, a.k.a standoff, should be a bit smaller with the nozzle size. Typically people use the paper reference (using a piece of paper to "calibrate" the standoff), which is about 0.004".
Make sure your slicing engine knows the change! Most slicing software will allow you to adjust the nozzle size. This can also be used to fine-tune your machine.
Beware of clogging: Clogging is usually a result of poor cooling between your heater block and your drive gear, poor filament quality, and/or incorrect extrusion rates. You might want to perform a benchmark print with the new nozzle to "rediscover" which temperatures work best with the new "basin" volume in the nozzle.

I'm sure there are many others, but this should help get you started.

With regards to clogging: a small particle that might harmlessly pass through a 0.4mm nozzle might very well clog a 0.25mm one.

Thank you. I have marked this as the correct answer but other people should feel free to add to the list.

In addition to the answer of tbm0115; special care has to be given to the strength and stiffness of the model. Lines are thinner and thus when using the same amount of walls and infill percentage, the walls will be less stiff. This requires a higher percentage of infill or more walls to counteract this phenomenon. Obviously, this will cause the print to take longer.


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Affordable 3D printing of reflector
Are there any 3D printing services or something similar to 3D print or injection mold light reflectors?
I'm trying to find something that is similar to PCB printing that allows you to upload a 3D design of a reflector and they will produce this reflector and coat it with mirror surface.

I jsut got some "Wax-like" FDM material from the manufacturer.
If we can print with that, I think it's possible to get the surface smoother after the printing, right?
And the next step will be casting with this wax print.

You can make flat reflectors with glass panels or acrylic panels and apply window mirror film. Ordinary window glass might be less expensive than acrylic and many places will cut to size, but unusual shapes might not be an option. The mirror film is relatively easy to apply and the packages have instructions included.
For the hologram pyramid you referenced, one could 3d print the bracket at the base. If your design is different, yet similar, that's an option for relatively easy construction.
100-200 pieces is really too small of a quantity to justify expensive injection molding. If the part is not too complex, one could create the model with 3d printing, then build a silicone mold around it, followed by pouring polyester or epoxy casting resin to make larger quantities. A better idea of the shape would be useful, but the information I've provided may head you in a practical direction.

I would not recommend extrusion printers for this, because they are unlikely to produce a smooth enough surface.  To get a clean surface, the irregularities have to be a fraction of visible wavelengths, which is to say on the order of 0.01 micron.
Without knowing what sort of reflector you're thinking of (flat? spherical? parabolic?), it's hard to recommend a specific optimal, cheap approach.  All in all, you're probably best off looking in standard catalogs such as Edmund Optics.

It would be a flat reflector, very similar to a hologram pyramid. Do you have any suggestion for a cheap way to make them at medium quantity (e.g. 100-200 pieces)? @CarlWitthoft


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What makes a good PLA filament?
The quality of the filament is frequently mentioned either as the source of an issue but also as the solution to a problem.
I know that the way you use,store and protect your filament will greatly impact it's quality, especially overtime, but here I'm interested to understand what makes a brand new, out of the air-tight package, good or bad? What to look for when you buy filament (specs,chemical,weight,...)? What are some brands that are notoriously know to make "high quality" filament?

I didn't answer the part of your question that asks about brands because I think it is likely to change a lot over time and yield opinion based answers.  (I think some of our friends here would prefer for you to edit out that line.)  :-)

@ChrisThompson thanks for the answer! I have "striked-through" the brand part of the question. While I disagree a little bit, I understand what you mean :-)

General characteristics of a "quality" filament:

Manufactured to a "high" dimensional tolerance.  Measure the filament in several places along it's length and check for consistency.  I'm pretty happy with filament that has less than 0.05mm difference between its thickest and thinnest diameter.
Lack of impurities.  I've never had a problem with impurities (that I know of) but I've heard and read about it.  Finer nozzle diameters will be more susceptible to clogs caused by foreign matter in the filament.
Good packaging.  You already mentioned it, but good packaging is a sign of a reputable filament supplier.  It should be sealed in a fairly "air-tight" bag with a desiccant to keep it dry.
Technical information available from manufacturer. Quality filament manufactures tend to provide information about their filament's characteristics and other information such as optimal settings, etc.
Good reputation.  This one isn't necessarily fair to newcomers, but there is lots of information online about the reliability and quality of various filaments.  In this case, google is your friend.  (Keep in mind that there will be plenty of complaints that result from poor settings/skill and have nothing to do with the quality of the filament.)

I hope this helps!  :-)

"Good packaging" should include a noticeable lack of kinks, as those lead to extruder jams.


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Auto bed levelling with Rumba board - Servo not deploying
Has anyone succeeded in installing the auto bed levelling on a Rumba board with Marlin firmware?
I have the last stable version 1.1.0 RC6.
I would appreciate some direction especially about:

How and which pin to activate for the servo?
How to test it with G-code before I move to settings of the probe sequence?

I have only installed the hardware for now (5 V servo) connected to Ext. 3 (EXP3):

Pin 2 (+5V);
Pin 4 (GND), and;
Pin 6 (PWM),

but I cannot move it with the G-code command M280 P0 S180. I have no idea where to put my hands on firmware to get this going. However my ultimate goal is to set the ABL.

To have two Z min switches you would have to wire them in parallel so that if either are triggered the board would see it, but this is not the standard way of implementing auto leveling, and you will want to ensure under normal operation that the mesh leveling switch will always hit first, and maybe set the second switch .5 mm lower, so there would be a light but not detrimental collision with the bed, It will be nearly impossible to get them both to trigger at the same time and still get the benefits of mesh leveling.

General note, I do not have this board so I cannot test these steps myself, read the documentation in configuration.h, it is very detailed and should guide you pretty well. I am specifically looking at Marlin 1.1 RC7 on Github, so the lines below may vary slightly from what you see.
As to the pins to connect on the board for the servo, pins_RUMBA.h is where they are defined/mapped. For other boards, there is a pins_[your_board_name].h that will define the pins for any given board.
The default Servo pin for Rumba is:
#define SERVO0_PIN         5

Pin 6 appears to be used for a third extruder heater.
#define HEATER_2_PIN        6   // EXTRUDER 3

In configuration.h you must uncomment (delete the slashes "//" at the beginning) the lines and fill in your stow and deploy angles in the second line for the servo. Find these lines under the Z probe options heading.
//#define Z_ENDSTOP_SERVO_NR 0
//#define Z_SERVO_ANGLES {70,0} // Z Servo Deploy and Stow angles

Define your probe offsets from your extruder nozzle:
#define X_PROBE_OFFSET_FROM_EXTRUDER 10  // X offset: -left  +right  [of the nozzle]
#define Y_PROBE_OFFSET_FROM_EXTRUDER 10  // Y offset: -front +behind [the nozzle]
#define Z_PROBE_OFFSET_FROM_EXTRUDER 0   // Z offset: -below +above  [the nozzle]

Based on your comment for using two z end stop switches, there is an option you must enable to use the standard end stop switch for homing, and only use the probe end stop for mesh bed leveling type operations. The config.h file has a lot of information on this, please read it for your own and your printers safety.
Uncomment this line:
//#define Z_MIN_PROBE_ENDSTOP

and comment this line:
#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN

Then set the carriage height to allow the z probe room to swing down and move:
#define Z_PROBE_DEPLOY_HEIGHT 15 // Raise to make room for the probe to deploy / stow
#define Z_PROBE_TRAVEL_HEIGHT 5  // Raise between probing points.

For autobed leveling uncomment:
//#define AUTO_BED_LEVELING_FEATURE // Delete the comment to enable

Then set probe points corners:
#if ENABLED(AUTO_BED_LEVELING_GRID)

#define LEFT_PROBE_BED_POSITION 15
#define RIGHT_PROBE_BED_POSITION 170
#define FRONT_PROBE_BED_POSITION 20
#define BACK_PROBE_BED_POSITION 170

#define MIN_PROBE_EDGE 10 // The Z probe minimum square sides can be no smaller than this.

Set the number of points to probe in each direction (x and y), default is 2, so it will probe 4 locations, the other common choice is 3, so it will probe a grid of 9 locations.
// Set the number of grid points per dimension.
// You probably don't need more than 3 (squared=9).
#define AUTO_BED_LEVELING_GRID_POINTS 2

That should be everything you need for a basic setup, although there are more options that I did not go through. Please look at all the documentation comments in configuration.h file as it is very comprehensive, even if it can be a bit confusing.
I hope this helps!

Thanks for your answer. The main issue I am experiencing is to get the servo to move. If I connect it as per my question it does not move. Reading your answer looks like I should connect it to 2, 4 and the PWM to 5 and then use Servo0 in the config and in the Gcode. Is this what you mean? I have added a pic in my question showing the ext.3 diagram.

Yes, the best I can tell you should connect the signal line to pin 5, which is pwm1.

I have done everything as per your answer. I had also to activate the servo support where I have defined the SERVO NR 1. I have checked the servo functionality with an arduino board and it is fine. However when I send the Gcode M280 P0 S90 the servo does not move! Not sure about what to do.

What angle is your servo currently at? If it is already at 90 it will not move, you can try another angle to check. Also are you sure the servo index starts at 0 on that board? Try M280 P1 S80, and M280 P0 S80. Between those two commands it will check both of my suggestions. Other than that I think I've gone as far as I can to help without having ever used the Rumba board.

Thanks for your help. Since I had to defined the number of servos in the section Servo support, I used 1, if I give a P1 it returns "servo out of range" while with P0 nothing is happening. Not defining the servo number, the firmware does not compile and returns the error "define number of servo". I have tested the servo again with an Arduino and it is fine. I tried both pins 6 and 5 ext. 3, but it does not move. If I run G29, the printer execute the ABL but the servo does not move. I moved it manually in an intermediate position to avoid having it already in the end position. Nothing!

I have not resolved my issue about the servo, however you have given me a good answer in reply to my question and therefore you have deserved the bounty. Thanks for the effort.

For future reference.
My issue about the servo not moving was caused by a wiring mistake.
The Exp. 3 has 14 pins has per this diagram.

However when phisically looking at the board, what you see is this:

I took the first 2 pins on the right of such connector and the 3rd one of the first row thinking that I was connecting pins 2-4-5 of Exp. 3.
I was wrong, because the first 2 (1-2) pins are not part of Exp. 3.
The right way to connect the servo is as following:

Then use PWM1 (pin 5 Ext.3)
I decided to leave trace of this issue and the relevant solution for someone that may experience the same issue.


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Large flat ABS print curling during cooldown
I am printing a large flat print, approximately 8" x 4" x 1/8". It has good adhesion when printing and lays flat when finished. I allow the print to cool slowly but the center of the print bows upward 1/16"-1/8". It bows in both directions but more noticeably in the longer direction. The corners are not curling up this is the center of the print lifting.
I started printing at 25% infill but have tried 100%. 100% bows less but still bows. This does not happen with PLA or PETG. 100% fill was printed with no fan. 25% printed with no fan for first layers and fan at 40% after.
Is there anything I can do to stop this from happening?
Printer: Lulzbot TAZ 5 w/ 0.5mm hotend in sealed enclosure. Heated bed at 115C, extruer at 240C. Environmental temperatures are 30-37C depending on the stage of the print. Hotter as it continues.
Follow Up Questions:
What is the ideal environmental printing temperature for ABS?
If a part were reheated could an existing arch be corrected?
Update: Build Plate Thermal Images w/plate set @ 115C

Sorry it took me a bit to get back to your question, but that's very odd that the part is bowing in the middle. My immediate thought is that there is a cold spot in your HBP, which would mean replacing the build plate. But, I would certainly leave that as a last resort. Another thought is the HBP is bowed itself, so try indicating across the BP with your nozzle to check flatness. Otherwise, are you sure you have good quality filament? You will typically see more bizarre issues with bad quality filament.

From my experience with ABS, your HBP makes sense if you're in a somewhat colder climate. Your extruder temp is okay, a bit high for my own liking, so you might encounter extra ooze/clogging in your prints. Your environment seems pretty hot if it's outside of your build space, are you meaning the build environment or room environment temperature? And, theoretically you could mold the part back into shape, but it may more hassle than is worth. If it's a small bend, you may even be able to use Acetone to soften the part enough to re-shape it.

@tbm0115 It could definitely be the heating on the print bed. I don't know how consistent they typically are but I have added an image to my question to show the inconsistency of mine. I don't think the plate is bent because other materials print perfectly flat and the bent parts placed back on the surface appear bent.

In terms of filament quality I think I am using decent filament. I've used Mitus ABS and IC3D ABS with the same result. The temperature is measured at one point in the build environment. I've made a Plexi box to enclose my TAZ 5.

The images are great! At first glance it seems that you have some dead coils in your HBP. However, it doesn't quite make sense because I think most HBP coils start in the center. So, you would think if the center was dead, the rest of it would too. I might recommend reaching out to @RyanCarlyle on this one. I'll keep poking around for better alternatives, but at this point I think you might be looking at replacing your HBP.

Short Answer: Make the environment temperature is a bit warmer to offset the cooling rate.
Long Answer
All materials shrink as they cool, but some materials shrink at a much higher rate than others. This is primarily driven by temperature coefficients and thermal conductivity of the individual materials. There are calculators available online that you can get more involved with discovering how this works mathematically.
However, in layman's terms, the temperature between your build plate and the first layers of plastic are so drastically different, that at a certain point the plastic becomes under tension as it shrinks faster/more than the build plate. Over time, since the surface tension between the part and the build plate is no longer in the way, the corner can continue to shrink.
Here are some options:

Ensure your build plate temperatures are correct acceptable. I've had success with 112C in NW United States. Increasing the temperature will be an attempt to bridge the gap between BP temps and plastic temps during the final cool-down.
Search for ways to "anchor" the part to the build plate. There are lots of resources on the internet on how to do this, so I'll spare you the list.
Increase your environment temperature. I highly suggest this because it can help reduce other errors you might encounter throughout the printing process, such as de-lamination, warping, brittleness, etc. I'm not recommending placing a space heater next to your printer (really, don't do that!), but perhaps even a space heater in the room can help regulate the environment temperature a bit better.
Consider other environment variables. Consider things like "Is my printer next to a window?", "Do I live in a particularly cold environment in general?", or even "Am I baking cookies in the next room?". A lot of these seemingly meaningless variables play an important role in ensuring quality prints.

(I know there's more, so I'll add onto this answer a bit more as I remember them)

Are you sure you read the question correctly? As I read it, it is about the print warping after it has completed (and the bed is cooling down), while your answer seems to be about how to combat warping during a print.

I think you misread my answer or I didn't write correctly. However, it's directed at post-print warping.

@tbm0115 Thanks for the response but most of your suggestions are addressed in my original post. The corners are not lifting during or after printing it is the center of the print. The print appears anchored to the heated bed set at 115C while printing but bends as the finished print cools. The printer is in an enclosure that maintains a relatively warm environment during printing and cool down. The print is allowed to cool on/with the bed further slowing the cooldown process.


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Wanhao duplicator i3 print bed support warped
As you can see in the picture, my heated bed support is too low on the right side, even touching the Y-axis chassis end plate.

This is only the case on the front of the printer. The back is perfectly straight. Do you know how this can happen and what can be done?

Has it always been warped, or has it only happened recently? How old is the printer? What material is the heated bed support made from? Acrylic, MDF, Aluminium, Steel?

It was not warped as I know and it's getting more and more to the point that it starts to hit the chassis on the front. The printer is exactly 1 year old and the heat bed support is made of aluminium.

I just checked mine.  It's only 2 weeks old and it has this same problem.  It's not hitting, but it is bent like this.

I sort of fixed it by adding another linear ball-bearing and bearing-holder to the y-axis on the position where the support bent down. This works without screws because the support presses down at that point.

okay, after ferociously dismantling the whole bed I found out that the bed and the bed support are perfectly straight!
So there is something  warping the bed and support. De Y-axis bars are perfectly flat too.
I found out that my table is not flat! This made the complete printer warped and even bent the print bed. put some cardboard under the frontleft foot and presto! As flat as it should be!


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Which type of extrusion problem?
I'm a novice in 3D printing. I have a Lulzbot Kittaz 3D printer with a hexagonal hot end of 0.35 mm. I have printed a test subject, and while I was printing I encountered this extrusion problem. I'm using ABS with 230 °C hot end temperature and 85 °C bed temperature. What kind of problem is this and how should I rectify it?
I took this photo when the printer printed the first layer:

It looks like you are not extruding at the correct rate. I would check your slicer settings for nozzle and filament size. Also check and calibrate for your filament diameter.
It looks like you could be getting better adhesion too. Lulzbot recommends a 110C bed temperature. That might help. (lulzbot.com/store/filament/abs under specifications)
These are some good resources to troubleshoot prints,
RepRap
All3DP
Simplify3D

Simplify3D

As Jmb2341 suggests, this over extrusion could be due to an excessive feed rate.
However, I would also like to add the possibility of your Z-height during the first layer being too close. For instance, if your first layer height is set to 0.4mm, but your print head actually moves as close as 0.2mm from the bed, there will be twice as much filament extruded than what it is actually room for below the nozzle. This, in turn, will appear like over extrusion, while the issue actually is your Z-leveling/height.
In general, unless you are using a raft, the amount of first layer over extrusion will often have to be balanced with the prints ability to stick to the bed. In other words, over extrusion during the first layer improves print stickiness, so that close bed leveling gives sticky prints but first layer over extrusion; while, distant bed leveling gives loose prints with more accurate first layer extrusion.
If you are wondering whether what you are seeing is over extrusion due to excessive feed rate or too close bed levelling, then you should try to inspect the extrusion of the top layer of some of your prints: If the top layer looks fine, your bed is leveled too close; however, if the top layer is over extruded as well, then your feed rate is too high.
Good luck!

You're right about the nozzle standoff. If it's a Z-height issue, then you'll see "over extrusion" throughout each layer. Unfortunately the photo doesn't tell us if that's the issue. However it is important to note that, if you can, specify the first layer (or few) to over extrude with ABS, you can reduce the chance of warping. The more surface area, the better with ABS.

Two things come to mind. First it is the first few layers. You could have the head Smashing into the print bed. Causing a massive build up of plastic the first few layers. And or you have over extrusion.

Take a piece of paper. you want the distance from the head and the
bed to be that width. Just enough friction to feel a light drag.
After that verify that your first layer extrusion multiplier is
under 1.5.
Make sure you are extruding the correct amount. Take a ruler.
Mark out 100mm. Have it extrude 100mm. Correct feed rates
accordingly.
Next check plastic diameter by taking the average over 10 samples
over a meter of plastic. Enter accordingly.
Then last you might have temp a bit high. Drop it a few degrees. Not a huge factor.