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It is worthwhile to protect electronics with a 3D printed PLA case?
PLA is flammable, but a good case can protect the main board from dirt.
Is it worthwhile to protect a circuit board with a 3d printed case?

Sidenote, PET blends (PET+, PETG, etc) are typically flame-retardant (will self-extinguish if the heat source is removed) and are thus a much better choice for electronics cases than PLA.

In the flammability tests I've seen PLA self-extinguished too. I forget who did them but it was a source I trust, maybe CNC kitchen.

It depends.
Protecting your electronics from being touched by random bits of conductive material which would short and fry them is always a good idea.
If it's something that will be visible, then a pleasant printed casing might go well. You might just as well use any other casing though, there's no requirement it be 3D printed.
For a very small circuitboard (an inch or less) heatshrink tubing might be a better form of protection. Or just insulating tape.
If you never intend to access the circuitry again and heat dissipation isn't a big issue, then just putting the whole lot in potting compound may work best for you - complete waterproofing and environmental protection.
Or you could just tape a bit of plastic from a 2l coke bottle over it, and get 99% of the protection you'll ever need, and still keep the circuit visible and accessible.
Ultimately, it boils down to: Do you want it to be covered? If so, by what? If you would prefer a 3D printed case, then do you want it enough that it is worth the time and effort to you?

3D printing cases is also nice to consider if someone other than yourself is going to be using the electronics. Think poka-yoke

As pointed out by Ryan Carlyle, not all 3D printing filament is flammable (such as PET and PETG), and the question therefore rather becomes:
Can 3D printing be used to make proper electronic cases?
And the short answer to that is yes. 3D printing allows to make customized cases of all varieties. Also, since there is huge variety of materials available, you not only restricted to cases of plastic filaments - should this be of interest.
Then again, it all depends on what you are protecting your electronics from. If you plan on submerging your electronics into water or throw them into a fire, 3D printing might not work for you at all. If dust protection is your only concern, however, 3D printed cases should do just fine in most cases.


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When building the ramps 1.4 is it safe to use small wires to jump the 5A, 12V power input over to the 11 Amp input
The idea is so you only need two long wires going from the power supply to the electronics boards. I'm sure I saw this done in a tutorial somewhere, but I can't for the life of me find the source. Also I just bought a kit and the build manual says to use four wires, but only two wires come with the kit, so I recalled that bit of advice in the tutorial and thought hmm either they shorted me those wires, or they just expect me to make do with two. Perhaps the jumping method is common practice? But then why have a plug on the ramps board with four inputs? Why not just two inputs and split it internally if need be?

I guess that the external split is at least partly done to force the user to utilize 4 wires. 16 Amps at 12 Volts is quite a bit of power and you don't want your wires or connectors to melt. If you use twice the wire cross section by using 4 instead of 2 wires, you also reduce the resistivity and hence heat created in the wire.
Put it the other way around: Using 2 instead of 4 wires raises the risk of your setup to catch fire.
Still, you can use that bridging technique, if you make sure that all your wire diameters are big enough.
I would advise you, however, to cut the wires that come with your kit in half and use the connectors in the way they were meant to. For optical appeal and less cable clutter you can still put the wires into some braided sleeve for example.

Good point about the resistivity making it a fire hazard, I hadn't thought about that. I'll probably just go to a hardware store and get some extra wiring!

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Filament Guides Drag
Backstory
I've had issues in the past with my drive gear "eating" my filament. It seemed that the filament quit extruding for one reason or another and the drive gear would slowly eat away at the side of the filament.
I eventually assumed it was the plastic filament guides causing unnecessary tension that the drive gear couldn't compete with, ultimately keeping the filament from moving forward. Thusly, allowing the drive gear to continue "trying".
My solution was to hang my spools above the machine to avoid using the filament guides feeding from the back of the machine up through the top.
Question
Can the plastic filament guides really cause that much drag? What other variables can I expect to look out for?
Machine: MakerBot Replicator Dual (1st Generation)

For an easy test, try manually pulling the filament through the U-loop of guide tube. How hard is it to pull through? It should only take 1-2 lbs of tension at most.
Then do a "tug test" on the extruder. Start it loading and grab the filament by hand to try to stop it from extruding. The Replicator 1/2/2x extruder style can typically pull ~8-10 lbs of tension and it should be fairly difficult to stop the filament. When you do stop the filament, you should hear clicking/thumping from the stepper stalling, NOT quiet grinding as the drive gear chews through the filament. If the grip slips rather than stalls, your extruder hardware needs to be tuned or replaced.
There are three common causes of excessive feed tube drag:

Use of polyethylene tubing instead of PTFE -- this makes a shockingly large difference in drag friction. You can use a heat gun or torch (outside!!) to tell the difference between PE and PTFE. PE will soften quickly and then melt fairly easily, whereas PTFE will simply go clear and eventually char without melting. Nylon is also sometimes used for feed tubes with acceptable results, but if you have any suspicion about the tube material, just buy new PTFE tubes from a reputable vendor like McMaster.
Too many loops/curves in the tube. Total drag friction is an exponential function of the total amount of curvature in the tube. You should have one good U-loop, no spirals or floppy zig-zags.
Excessive friction on the spool rotation. Any spool back-tension gets greatly magnified through the feed tube per the capstan equation. This can be caused by a bad spool holder, or if the filament is knotted on the spool due to letting the end of the spool loose during handling.

I have a few hundred printing hours on a Monoprice Dual Extrusion, which is essentially the same thing.  I've had a couple random issues that lead to filament stripping by the extruder motor:

Clogs (either a buildup of material over time, or from over-retraction)
Filament kinks around the spool holder
Some other restriction of the spool's rotation

I suspected the guides early on, but the grips on the rotor are actually fairly strong and the guide tubes are smooth enough to not cause a problem by themselves; I'd recommend looking at the other ends of the assembly first, as they're more likely to cause a problem.  If you preheat the nozzle, open the tensioner on the extruder stepper, and can't push the filament into the nozzle with your fingers, the motor won't be able to do it either.

The friction inside of the guide tubes is fairly minimal assuming that the lines are straight and there isn't anything else inside them. My guess would be that you may have another issue. Reducing the drag in the guide tubes while it may reduce the problem of clogged nozzle, might just be hiding the symptoms of another problem.
I've heard, but never tried adding a dab of Canola oil to the tip of your filament prior to feeding it into your extruder. Specifically for Makerbots.
Link my source:
https://groups.google.com/forum/#!topic/makerbot/Wn-MKC1Ybm0%5B1-25%5D

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Designing clips that won't break
As my first project, I'm trying to design a holder for glass vials, for a scientific application. The photo below shows the latest design iteration, and also shows the problem with it:

As you can see, one of the clips that's meant to hold the vial in place has broken off. This happened after inserting the vial once or twice.
I think I understand the reason for this. It's because I'm printing in the orientation shown below, in order to avoid the need for supports. (This will be more important later, when I scale it up to an array of many holders.) This means that it's relying on the strength in the z dimension, which is much weaker than in the other two directions, because it relies on the cohesion between the layers.

My question is whether I can do anything about this by changing the design of the clips, without abandoning my hope of support-free printing. I don't care at all what the design looks like, except that as much of the vial as possible needs to be visible from the front. I'm printing in ABS.
I have tried varying the thickness of the clips. Thinner ones don't break as easily, but they are a bit floppy and aren't very good at keeping the vial vertical. The ones shown are the thickest I've tried - I'm afraid that if they're too thick they won't bend at all. (The vial is supposed to be inserted from the front rather than the top.)
Edit just as an update, here's what it looks like using John Biddle's suggestion, which works perfectly:

Try printing the original design vertically. This is about print layers which tend to segregate.

Nice T-slots :)

It looks like those clips are thin and need to bend pretty far to let the vial out. Try to make the clips thicker, but with a smaller clip to retain the vial so that it doesn't have to bend as much.
This is what I'm thinking, in beautiful MS-PAINT form:

Man, I was going to suggest this, finished my MS Paint example, only to scroll down and see yours :(

Thanks, this is a really good idea. If I don't change the printing orientation then having the clips sides be vertical also means each pair of layers has more surface area in contact with each other, so it should be stronger.

I agree with the previous assessments -- printing vertically for that part of the clip will definitely alleviate the layer adhesion being your weak point.
You might also consider splitting that clip as a separate modular piece (which will clip/socket/bolt into the stand).  Depending on implementation, this would give you the ability to

Print that part vertically without supports
Swap the part if it breaks, without having to print the whole assembly again
Preattach the clip to vials, which may be good or bad depending on your usage

Printing the clip as a separate module also saves a ton of printing time and material required.

Considering that you wish to print the clip in the vertical orientation but without supports, I would suggest that you create a suitable taper of the clip from the bottom. The taper would provide necessary support-free support but may reduce the amount of bottle access one has to remove it from the clips.
As such, you could also reduce the amount of the straight vertical segment of the clip at the front, which would allow the support-free support to start at a higher level from the bottom.
If the bottle bottom encirclement is raised, you'd receive additional retention. You could then reduce more the upper encirclement and taper for easier release.
I too prefer to design models that require no support, but have run into the same circumstance, where the weaker axis takes a disproportionate load.

Come on. Wider clips will just survive a bit longer.
The real cause is the orientation (plane) of printing.
Continues filament layer will always be more durable than few layers sticked together.
So the question is why not to change printing plane?
You can use better design which utilizes support without using "support material"

The Short

Just print vertically
Reduce the clip size to bring them closer to the centerline
Try a vapor treatment or epoxy to increase strength

The Long
Ultimately, printing the object vertically (so the clips are printed horizontally) would be the strongest solution.
Alternatively, you could adjust your model to bring down the size of the clips to reduce the strain. Consider making more of a cup or cone on the bottom for the vial to slide into center. Then reduce the length of the clips to bring the closer to where the center of the vial will be. Make sure, however, that your clips still curve slightly around the center (and maybe a mm or two beyond). From a design point, the bottom clip is probably unnecessary.
Another option might also be to use a small vapor treatment on the ABS. Depending on how deep the alcohol penetrates, it could diminish some of the issues with the part cracking along the grain. This is just a fairly labor intensive process compared to some of the others posted here.
Side note, those are great looking prints! I like how smooth ABS can look. Its hard to tell, but it looks like your part has a bit of warping on the bottom. Definitely look into some of the warping questions here on Stack.

Thanks, this is all useful. It doesn't look warped in real life! I think that's an issue with the camera's optics.

No problem, glad to see my other suggestions for clip design helped too.

Printing the model vertically should certainly be considered, as that will alleviate your issue by a whole lot. If altering the design by adding a taper to your model isn't what you are looking for, placing a manual, removable support structure at the outer edge og the overhang could also be an option. This way, you could print the overhang as a bridge, making it much easier to print vertically.
Also, have you considered using another material than ABS? There are a large variety of filament types available that have better semi-flexible properties than ABS, without sacrificing overall strength. For instance, PETG and Taulman's Alloy 910 filaments are both very strong, and surprisingly flexible.

Thanks. Probably I will print it vertically in the end. The reason not to is that it will be an array of these stacked on top of each other, so when it's finished it will be quite tall and the bottom part will become an overhang. But maybe I'll just print each layer separately and stack them. I'm limited to materials available for the Zortrax M200 and the eventual design needs to be white, so I think ABS is the only option.

If you don't want your clip to break, you'll have to engineer in some form of flexibility in a strong part of your design.  For example, right now it looks like the bases of the clips are sitting rather solidly on the underlying surface such that it can't move.  I'd suggest that instead it might be better to have two clips attach separately to the bottom using a "post", and have each post attached to the solid part of the base with a piece of plastic whose horizontal cross-section is a somewhat-rounded accordion-style double zig-zag.
From the top:
Having multiple "pleats" will mean that each degree that the clips flex outward will only require each pleat to flex a fraction of a degree.  You'd have to play around to find out what number of pleats would give a suitable degree of stiffness and flexibility, but if the printer renders the design by drawing the zig zags, stresses should be concentrated in the directions where the material is strongest.


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Printing insoles
I would like to make custom insoles for my wife.
This company makes a flexible filament that will be soft to stand on:
http://recreus.com/en/
I do not currently own a printer.
How can I measure her feet and transfer the measurements to the printer?
(one of these comes to mind: http://www.eggheadtoys.com/pin-art/)
How can I measure the inside of the shoe?
What kind of printer can print with the flexible filament?

Here is a post that covers how to scan a foot and make a form fitting insole - https://web.archive.org/web/20180429035945/http://www.gyrobot.co.uk/blog/my-adventures-with-3d-printed-insoles-part-4-4
Here are links to the rest of the blog - Part 1 of 4 - Part 2 of 4 - Part 3 of 4
Any printer should be capable of the temperature required for flexible filament.  The main problem with flexible filament is the path between the drive gears and entrance to the hotend must be completely constrained or the filament will push out of any gap.  Ninjaflex is very flexible and absolutely will not work unless you constrain it right after the contact point with the drive gear.  Semiflex is another flexible filament but quite a bit stiffer than Ninjaflex, I've never used it but it should be a bit more forgiving on the path requirements.
I know there are several other flexible filaments but I've never worked with them so I only mentioned Ninjaflex which I have used.
The model used in the blog can be found here - http://www.thingiverse.com/thing:586514

In short, my opinion is that 3D printing is not the most ideal or cost effective means to accomplish your objective. I'm sure with just as much research, you can find an existing consumer product.
However, to answer your question, you have a few options that come to mind:

Simply make a mould using supplies from your local craft store. Once a mould is made, look into a castable material that will be comfortable, though this may be difficult.
If you're dedicated towards 3D printing the insole. Try getting hold of a local service that can use a 3D Laser Scanner to get a mesh model. The same service might even be able to create solid model of the desired insole if you have dimensions of the shoe you wish to use. Next, you'll need to contact another service to 3D print the insole (most likely in nylon or similar) or, if you have a 3D printer, print the insole yourself. If you are considering printing yourself, and have not before used a material like nylon, please review the material specifications. Some suppliers recommend the use of a heated build plate with these type of materials to ensure the material properties are retained during heating/cooling.

I'm suggesting Laser Scanning as it will be the most economical and flexible means of reverse engineering the dimensions you're requesting. Other options, such as a Coordinate Measuring Machine or X-Ray may would be quite uncomfortable and impractical.
Ultimately, I would look into something like this instead. I'm not endorsing any product or company, but something like this may be the best solution for you.

Many questions in one post, but I'll address only the first. Consider to use a shoe with a flat insole, perhaps even what is commonly called a flip-flop. If your objective is to perfectly match the curve of her foot bottom, this should work. Apply a layer of polymer modeling clay, plasticine or similar material. It should be warm enough to permit her foot/feet to settle in and push enough material away to remove any voids. If voids appear, one could then add a few blobs and repeat the pressure.
Obviously some will ooze from the sides, which will have to be trimmed away. Trim a sufficient amount to fit her regular shoes and you'll have a reasonable match of the necessary fit.
The resulting shape can then be scanned with a 3d scanner and converted to a 3d model. Even if the clay is excessively thick, the typical 3d model editor can slice away the excess, although one would have to make an almost arbitrary judgement for the location of the slicing plane.
Another option comes to mind. There are various silicone molding products. I've used one from makeyourownmolds.com that is of a consistency of frosting. When mixed together and applied, it makes a perfect duplicate of the item, in reverse. Another product sold at the local HobbyLobby is a similar molding compound that is more akin to the modeling clay.
Both compounds will release easily from skin, are non-toxic and would provide a more durable model from which to scan.
I think one difficulty you may have is how to determine the correct foot pressure and posture to achieve the desired results. The modeling clay would give you more support and probably be more accurate. If your objective is to provide the same support as a bare foot, the silicone molding method would be more accurate.
If you stretch the concept even further, once you have the silicone or clay mold, you would be able to use the pin-art concept. The idea of measuring each tiny pin is mind-boggling, though.

I have given this some thought prior since, I am also in need of such things, so here is my 2 cents.

How can I measure her feet and transfer the measurements to the
  printer?

If you want to be very accurate, then you will need a 3d scanner. Failing this, then you're most likely going to have to take an outline. Just let her stand on a piece of paper and draw an outline of her foot. Next get a document scanner and scan the trace. You could also take a photo but you will have issues getting the correct scale. Assuming your outline is black, convert the scanned outline to a vector file using an online source or Adobe Illustrator (e.g https://vectormagic.com).
Once you have a vector outline then import it into your cad software and begin modeling the insole.

How can I measure the inside of the shoe?

Remove the exsisting insole (if possible) and scan it in a document scanner.

What kind of printer can print with the flexible filament?

Any direct drive extruder can print with Ninjaflex or other flexible filament. You could also try PORO-LAY, but it is much more expensive. I'd advise you to do you test runs in PLA or something cheap until you get the correct fit.

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Easiest way to build a horizontal hotend mount at home, without printing
For my Frankenstein's printer I am at a loss with the hotend mount. I cannot drill holes of 16 (upper diameter) and 12 mm (clamping diameter, 6mm high) which i would need to mount the E3D V6 clone I have.
What I am looking for: a hotend mount plate that tightly fixes the hotend while having some holes for screws to mount it to the horizontally moving x-y drives. As I cannot print yet, it needs to be manufacturable at home. I thought of something like this:
http://www.thingiverse.com/thing:285405
I could get a piece of wood thin enough to fit the 6mm gap for the hotend, would not really be able to put any screws through it along the flat axis. also I would have to glue the layer with a 16mm hole on top. Not to say that I don't own a drillbit of 16mm diameter...
Are there some completely different ideas around which I didn't think of yet?
Additional info: the x-y axes are made from a scanner bed and an underneath mounted dvd drive laser positioner. Ideally, I'd want to mount the hotend directly to the DVD drive but a) there is almost no space for that, and b) I'm pretty sure I will burn the DVD drive's motor somewhere along the way, so I don't want to put too much work in the individual DVD drive.

You could cut a v-notch groove in a piece of plywood to hold one side of the groovemount neck, and then use a bolt through another piece of wood to push the neck into the V-notch.
There are lots of options when building RepStraps and JunkStraps. Really depends on what sort of hardware and fabrication capabilities you have on hand.

If you do not have the tools to fabricate this component yourself, but have a 3D model available, I would suggest getting someone else to 3D print it for you.
There are multiple options for getting your model printed, such as:

Friends
Your local makerspace, library or similar
3D Hubs
MakeXYZ
Shapeways
Sculpteo
and so on..

Good luck!

This is not an option for me since I want to reduce the bought parts as much as possible. Especially if I can't reuse them afterwards. Your repository of printing services and the idea might be very useful for others, though.


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Is 3D printing a good way to save money?
If you already have a 3D printer, would you say that you have saved money on buying the printer, buying models and then printing the models, compared to buying something alike in retail?
Would you say that saving money is an argument to buy a 3D printer?

I would say that the general answer to your specific question is no. If you want to justify buying a printer because of all the things you could print instead of buying that is not going to be easy.
If however you are a DIYer and you have some CAD skills, or are willing to learn some, then consider the 3D printer as another tool you can use. There are plenty of stories about people who fixed some very expensive thing instead of having to buy a whole new one for hundreds of $/£; so if you have a specific use in mind then it may be justifiable to you.
I have made and fixed stuff around the house, but it's often things you simply couldn't buy, or could have fixed some other way.
There is an ever growing library of models available out there, and many are free. I recently fixed the leg on my keyboard with a printed one which I found on thingiverse, took minutes to print and the keyboard is part of a wireless set which would cost £30 to replace, so that was great but you won't normally find exactly what you want like that at this time.
And lastly it's not plug 'n Play yet, so you need to be a tinkerer at heart to use most printers out there right now.

A mini CNC machine might be a better option atm.

Yes and No.
There are two sides of this, yes and no. Why I say yes is because there are little things that the 3D Printer can come in use for, like creating charger holders or just little household objects. The no side of this for me would be because of the cost of the filament in general and the maximum object size you can create with your 3D Printer. I know they have bigger ones out there, but you aren't going to make anything too big. Another reason it's a no is because of duration of time. It may save you money, but your going to be spending a lot more time and possibly more money the bigger your objects get, which is the only reason I'm not trying to get one at the moment. I'm choosing to wait until technologies advance to get my personal one, where it doesn't take over an hour to print out a keychain tag.
So yes, you probably could save money in the long run, depending on what you create with it based on size and how much filament you use, but I'm also going to say no because of the disadvantages the 3D Printer has. I personally would wait for technology to advance in the next 5-15 years before buying one that has a lot more power than these, as the one's currently in the market are expensive.

EDIT: As I stated in my reasoning, I currently do not own a 3D Printer, but I do use one at my school for educational purposes and I do know the hassle on time and money for creating products that are relatively small in size.

You'll never net a profit 3D printing the equivalent of Dollar Store trinkets. Commercial-scale injection molding costs pennies per part, while 3D printing typically costs dollars per part. It's great every so often when you can replace an out-of-stock widget and rescue a major appliance from the trash heap, but those instances are pretty rare.
What 3D printing lets you do is make stuff that simply wouldn't exist otherwise. That could mean clever gadgets that can't be manufactured any other way, or niche items that don't have enough volume to be economical via traditional manufacturing and sales channels, or one-off prototypes or art projects. Those may be very high value items! But it's difficult to assign a dollar value to them.

What 3D printing or additive manufacturing is good for is printing small and delicate stuffs. examples: scaffolds, tissues, human organ. i've seen some people use 3D printing to print bone or a part of it.
Also, it's good for fast prototyping, especially you don't want to wait for the machine shop forever. that's where 3D printing comes in.
What is not good about 3D printing is the piece cannot withstand normal force/stress as compared to regular casting/manufacturing ways. 3D printed work piece are easy to break compared to other methods. no matter what alloys/plastic ink you use, there is always something better. 3D printing don't give the best. as such, manufacturing still relies on old methods.
let's review the pros and cons of regular manufacturing (mfg) and 3D printing:

regular mfg:

+cost: design mold, more time/money investment to make equipment
+profit: faster+cheaper (in term of $/product) for mass production

3D printing

+cost: cheaper machine (usually but not always, depending on the input materials, could be alloys, plastics, etc.), laser type (diff commercial printers use diff laser)
+profit: cut time to make equipments because it's ready avail, more expensive but also more control so each of these methods have their goods and bads. personally i think it's usually worse than better compared to regular mfg so it doesn't make much sense to me.
So in my opinion, no.

Hi, kensaii, and welcome! I think your argumentation is very good, but could you perhaps elaborate on how this does or does not make 3D printing viable for saving money?

hi @TormodHaugene, right, great questions! let's review the cost and the profit of two methods (3D vs. regular manufacturing)

regular mfg:

+cost: design mold, more time/money investment to make equipment
+profit: faster+cheaper (in term of $/product) for mass production
-3d
+cost: cheaper machine (usually but not always, depending on the input materials, could be alloys, plastics, etc.), laser type (diff commercial printers use diff laser)
+profit: cut time to make equipments because it's ready avail, more expensive but also more control
so each of these methods have their goods and bads. personally i think it's usually worse than better compared to regular mfg so it doesn't make much sense to me.

Thank you @kensaii for pointing that out! I would like to recommend you to add it to the answer though, as that will make it both easier for you to format it properly, and also make it more visible to other users! You can edit your question by the link below your answer. :-)

thank you @TormodHaugene for the suggestion. have a great day!


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HE3D-XI3 3D printer Repetier software config help!
I am new to 3d printing and had bought my first 3d printer a couple of months ago. I have it all put together and the software uploaded to the Arduino. However, I need some help with configuration and calibration of the printer. I understand that there is a configuration file that can be changed and uploaded again the create those changes. I also have worked with Arduino before so I know the IDE.
When I turn the printer on everything works, as far as I know. I did some tests to see if anything was wrong, but I couldn't find anything. However, when I hit home for all of the x, y and z axis to go to their starting marks, it tries to go past the rails and comes apart. From what I understand this is a configuration issue.
I tried to contact HE3D about this, but received no answer, so you guys are my last hope. If you need any more information to help me, let me know and i'll try getting it to you asap. (I also have read the documentation on Repetier and the installation and configuration section but my brain for some reason is not clicking into gear.)
Thanks for the help in advanced!!! Here are the specs:
https://www.3dprintersonlinestore.com/reprap-prusa-xi3

Hello, DakotaMiller, and welcome to 3D printing beta! I'm wondering: which firmware are you using for your printer (you mention Repetier, but I'd just like to confirm this)? Also, have you manually tested your endstops using the M119-gcode? More info: http://reprap.org/wiki/Endstop

I did not use the code. However i did test it using the repetier host software on the computer by typing in a like 10mm for it to move and pressing the endstops myself. Also it moves away from the endstops when going to home.

The files i used for the frimware and software can be found on the site i mentioned.

If it moves away from the endstops when homing, try flipping the motor plugs where they connect to the mainboard  to make them run the opposite way. Then see if it homes properly.

@Ryan I can due that but the circuit diagram say that it needs to be the way I put it together. If I were to flip those would it damage anything?

Flipping the motor plugs is 100% harmless and will reverse the direction the motors turn.

Sweet, I had read somewhere that when the guy was putting his together he kept frying the driver boards, but I must have miss understood. This will solve a whole bunch of problems. Plus it makes more sense that the printer would use the endstops to judge distance. Thank you so much Ryan!

@Ryan it worked! I kept thinking that it needed inverted in the code. Anyway if you post the answer ill mark it as the solution. Now i can move on to calibrating it.

I recently bought an ei3 from he3d .. what a joke.. I had similar issues with limit switches being ignored by the unit causing it to attempt self-destruction when hitting maximum limits.. I finally found a copy of the firmware which I recompiled using arduino builder, as it wouldnt terwith the standard arduino ide.. you have to configure firmware to disable software max limits, and enable maximum hardware limits.. they didnt program the controller properly.. now if i can figure out howto get filament to load i might print something.. ive been at this for almost two months.. I also bought the c

@Jason don't feel bad after I started printing with mine it took me almost a year to get the hang of calibrating it every time to have really good prints. Stick with it. I have since bought 2 other printers and one is ok, it was put togeather in factory and the other was even worse then the he3d printer.

Based on some troubleshooting in the question comments, it appears that the issue here is the motors running the wrong way. This can be fixed EITHER by inverting the motor directions in firmware, OR by simply flipping the orientation of the motor plugs where they connect to the controller board. Flipping the plugs is an easy and quick way to reverse the phase of a stepper and thus reverse its direction of motion.


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What kind of silicone glue should I use to attach my thermsistors?
I was watching a couple of videos about installing a Thermistor on the heat-bed and extruder of my Prusa i3; both videos mentioned that if I use either Sodium Silicate (Muffler & Tail Pipe Sealer) or Heat Resistant Silicone Glue to attach my Thermistors, I would be able to get a more accurate temperature reading.
Is there a particular kind or specification that is best for use in their the Heatbed or the Extruder?

The main requirement here is temperature resistance. A 3D printer extruder is very, very hot, and will easily exceed the ratings of many typical silicone glues in normal service or during a runaway event. (You should always plan for an eventual thermal runaway. They're alarmingly common with cheap kit printers.) Even high-temp glues will not survive the temperatures an extruder can reach at full power if the firmware locks up.
Muffler putty is popular for fixing thermistors because it's one of the few widely-available ways of attaching a thermistor that will easily withstand the heat. In fact, it will survive after the aluminum hot block melts. (Yes, that can happen.) But muffler putty is fairly brittle, and has a different coefficient of thermal expansion from aluminum, so there is some risk of the thermistor detaching over time. I really don't recommend puttying thermistors used in extruders -- many people do, but it's less robust and less secure for long-term use than the proper hardware fixing methods found in modern hot block designs like the E3Dv6. The temperature sensing is sufficiently fast and accurate simply by putting the thermistor into a pocket in the hot block, without any kind of potting around the glass bead.
High-temp RTV glues are very suitable for heated build plates. Pretty much any RTV (such as from your local automotive repair store) is fine if you just want to attach a thermistor to a plate. However, silicone heaters will require silicone adhesives. I've had good success with Dow Corning 736.


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Cons to UV printing
I've been curious about the various UV/Laser printers in (or coming into) market that use liquid resin. I've seen the samples of the Pegasus Touch, Form1, and the Carbon3D as examples. I like the specifications of the quality that machines can put out. However, in my experience with FDM printing, there almost always seems to be something not quite right about the print.
So, what are some major maintenance considerations for these types of 3D printing? Also, specifically, are supports and overhangs as much an issue in these types of printers as with FDM/FFF?
Here are some things I consider major maintenance considerations in FDM:

Extruder Clogging
Build platform conditions (i.e. levelness, clean, type of tape, bubbles in tape)
Variances in material quality (i.e. diameter, purity, physical conditions)
Mechanics of the machine (i.e. belts, rods, gear teeth, etc.)
Build environment (i.e. ensuring steady temperature in the build environment, minimize draft)

I'm not necessarily looking for printer recommendations, more so technical insight on the technology.

Now that this question is nearly 6 years old, I would love to see an update based on the technology changes since 2016.

Taken in order your questions:
Maintenance for a resin printer means keeping the vat or tray clean, using appropriate methods to remove the unused resin (or leaving it in the vat per manufacturer's directions). Cleaning the tray should be done also per manufacturer's spec, although each printer's user forum may provide better or more effective options.
The Pegasus Touch has a caution regarding dripping resin on the mirrors, so there's operational care considerations for these types of printers.
There is a build platform for these printers. The flatness and level are as critical or more so for resin printers, as the resolution can be astonishingly high. If any portion of a print does not bond to the platform, that entire print will have a failed section, creating an entirely failed print. Gravity is not particularly helpful in that respect, at least with the Pegasus Touch.
The release medium varies from device to device. The Pegasus Touch originally used PDMS (silicon release compound) and now uses what's called a SuperVat. The plastic material in the SuperVat is purported to provide better release and fewer failures, along with increased lifespan. PDMS becomes cloudy from repeated printing in the same location and can be torn away from the vat if the print does not properly release.
I've become aware of a product from Australia that has had good reports from use in a B9 Creator resin printer. The report indicates that it releases the model quite easily and barely turns cloudy. I have an order pending for this material, as I am hopeful it will perform as described.
The mechanics are also varied. One expects a system to raise and lower the build platform and to direct the laser or illumination system (DLP), but generally, this type of printer is somewhat simpler mechanically.
Because I live in a hot humid climate, my Pegasus Touch remains in the box, and my brain is about to explode with what I've learned of using it. Environmental conditions are likely to vary with different machines. I've seen references that 70 degrees F is too cold, others that say 70-75 degrees F is just fine, anything higher is too hot. Another user says that 65 degrees is good. The type of resin also becomes an important factor for environmental conditions.
The laser will create heat in the resin, so I'm inclined to believe that cooler is better. Different colors require different durations of laser light, somewhat akin to various plastics having different temperatures.
supports and overhangs are important considerations in an SLA or DLP printer, just as they are in FDM.
Expect also that many of the resin printers require that the user purchase only the product provided by the manufacturer. This isn't necessarily a negative as most of the resin sources are priced similarly.
If I've missed any part of your question, let me know.

Do you have a link available for the product you mentioned for releasing models? And thank you, your response was very informative!

The location from which I purchased the breakable glass is:
http://www.aldaxstore.com.au/p/1187443/breakable-glass-silicone-1kg.html
The discussion regarding its suitability for pdms replacement is here:
https://www.b9c.com/forum/viewtopic.php?f=8&t=2637
If you are in Australia, there is a less expensive source, but they don't ship to the USA.

Despite how many vendors make it appear, resin-curing SLA/DLP printers are industrial or commercial tools that are really not suitable for home desktop use. Here are the major downsides:

Significantly more expensive to operate than FDM printers, in most cases.
The resin is seriously toxic until fully cured. Fumes can be an issue for users handling raw resin, and you should NEVER put a photopolymer print into a chemically-sensitive environment like an aquarium or children's toy.
Prints require messy post-processing to rinse off excess resin (usually with rubbing alcohol) and additional UV light exposure to finish hardening the photopolymer. The used alcohol/resin rinse mix is basically hazmat waste.
In bottom-up printers, the window in the print vat is typically a consumable. Some printers require replacing the vat ($$) after every liter or two of cured resin. (Technology is advancing rapidly here though.)
The peel mechanism in bottom-up printers is often a major source of print flaws, due to the need to rock/tilt/slide the print to free it from the vat window.
In top-down printers, you have to pay a large up-front consumables cost to initially fill the resin tank. (There are workarounds here like floating a layer of resin on brine, but these have their own technical issues.)
If you leave the resin in the printer for an extended period, you'll probably find a hardened layer on the surface from stray light exposure and have to clean out or replace the vat.
Resin vats/tanks need to be kept clean and free of cured resin debris from failed prints or stray light.
Every combination of resin chemistry, printer light source, and printer optics requires specific tuning to dial in the photopolymer curing behavior. This means it's somewhat difficult to change resin brands, and you may effectively be locked into the printer manufacturer's resin. Many light sources will change in intensity or develop dim regions over time as they age, which will either harm print quality, require period recalibration, or require frequent light source replacement.
There is a limited number of options for print materials. Technology here is advancing rapidly, but for the most part, SLA/DLP prints are non-load-bearing models with a limited range of color options.

These are some pretty significant "user experience" downsides compared to a consumer desktop FDM printer. It's more hazard, more work, and more cost than FDM. SLA/DLP is primarily advantageous where high resolution or high print speeds are required.


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Convert G-code to SVG
This question is a bit of an edge case for what 3D Printing SE covers, but it has to do with topics most closely related to 3D printing.

I've found a plethora of ways to convert SVG (vector graphics) into G-code, but I can't seem to find any way to take a series of G-code movements and convert them into lines as a vector graphic.
Why would I want to do this, you ask?
I have a Silhouette, which can cut paper, or draw on paper, depending on if you insert a knife tool or a pen tool.
I have a polar draw bot (Makelangelo) which doesn't want to behave... the motors keep losing steps when the number of steps/second is low, and thus positioning gets off.
I want to use the drawing algorithms in the Makelangelo software to create drawings using my Silhouette, but the Silhouette wants vector graphics, not G-code.
The simplest way in my mind to do this is to convert G-code generated in the Makelangelo software, convert it to a standard vector format (SVG), and import it into Silhouette's software suite.
Alternately, if there's a way to send G-code directly to my Silhouette and have it work, that'd be a much better solution.

I've converted gcode into an XYZ format before. With a couple Regular Expressions, you can reverse engineer a gcode file relatively back into 3D model. Is this kind of what you're looking for?

Sort of. I am dealing with x, y, and "z", where z is lifting/lowering the pen. So 2D.

There are a number of programs available which will convert g-code to DXF, a common drawing format. If your device does not support DXF directly, there are a number of programs to convert DXF to SVG. I would paste links but a quick search with your favorite search engine should give you useful results. The better conversion programs will allow you to eliminate movement g-code entries, which prevents connections between lines. I did not paste links, as my research shows such variety as to be overwhelming.

The conversion itself should be fairly easy using such tools, but most such tools will convert each gcode movement to a separate vector. So, for example, if your drawing was a circle you'd get an awful lot of tiny strokes, instead of a single SVG, DXF, or similar "circle" object. Some devices do have gcode "arc" commands, but they might or might be used in your files. That should work fine, so long as you don't need to edit or change anything....

I have run into that which you describe. It can make the result unpalatable, to be sure. I believe that the free program Inkscape, which reads vector files, has the ability to smooth such tiny strokes, but that turns a semi-automatic process into a much more manual one.

I've found a possible solution, but don't have a file suitable to test. The web site https://makeprintable.com/ will accept g-code files (extension .gcode) and convert to an STL file. In the test I attempted, the gcode was for an outline of a rectangular block and the stl created was vertical. I used Meshmixer (free) to rotate it to the horizontal, then used Slic3r (free) to slice to SVG. When opened in Inkscape (free) it appeared damaged, but the paths were there when clicked. When opened in Illustrator, same result. The paths exist and need to be colored?

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Beginner in calibrating HE3D Prusa XI3
This is my first time calibrating my printer and I'm not sure where to start. The printer is running Repetier v0.91 firmware that came on the SD card that came with the printer.
Anyway, the question I have is where do I start calibrating and how would I go about it? I have read on Google many ways and it seems there are different opinions. I am reading this at the moment: RepRap Wiki - Calibration.

There's a great tutorial here on youtube.
And personally my favourite is this tutorial.

The first youtube link is broken.

Instead of using non-descriptive here, or tutorial as link text, it is better to include the actual title of the link, so that people can search for the item, in case the URL is corrupted - as is the case here...


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Real life stepper speed
I am wondering about the speed that my steppers should achieve in regular operation and what the determining factors are, from theoretical hardware facts/limits to software limitations that can influence performance.
I do know about the basic properties of stepper motors such as the torque relation with speed, which I read some while ago from this source (for anyont stumbling into this question later):
https://www.geckodrive.com/gecko/images/cms_files/Step%20Motor%20Basics%20Guide.pdf
So far Wikipedia (https://en.wikipedia.org/wiki/Stepper_motor) easily turns up the following statements with regard to my question:

Thus when controlled by an L/R drive, the maximum speed of a stepper
  motor is limited by its inductance since at some speed, the voltage U
  will be changing faster than the current I can keep up.

and  for chopper drivers:

This requires additional electronics to sense winding currents, and
  control the switching, but it allows stepper motors to be driven with
  higher torque at higher speeds than L/R drives

Obviously the amount of steps/revelation will change the speed, too
However, all this does not help me to determine what the real life speed of my stepper should be. Additional firmware parameters clutter up my (beginner's) brain even more (and I haven't had a too deep dive into that yet).
In general I understand that the frequency we use to send the steps to the stepper is the main determining factor, also 'reduced' by microstepping, if applied. We cannot keep the current up as much as needed due to timing/inductive/electronic properties of the motors, so we lose torque or finally steps. A higher voltage helps to bring the current up faster, so the steepness of the current increase can also limit the maximum applicable frequency. The frequency itself is given from the controller board to the motor driver, hence is set in firmware.
All in all, apart from what makes sense to utilize in a 3D printer setup, what are the determining factors of the stepper speeds that can be realized and how to they transform into real life values for our printers? Also I'd be interested in how the determining factors influence the reliability and print quality regardless of the mechanical difficulties that arise with print-speed.
/edit:
I found these to exist on electroncs SE:
https://electronics.stackexchange.com/questions/71270/maximum-speed-of-stepper-motor
https://electronics.stackexchange.com/questions/129064/slow-down-stepper-motors-speed-using-stepper-driver-drv-8825
However, I think the question here is relevant and specific enough for 3D printing to exist here alongside.

The four main motor speed limits in a 3d printer are:

Firmware step generation frequency limits
Firmware motion planner effects
Loss of torque and precision due to motor coil inductance and back-EMF effects
Mid-band resonance

Step generation rate limits will depend on the firmware and controller board used. There is a significant range, particularly when 32bit firmwares and RTOS-based platforms like MachineKit are compared to 8bit firmwares running on Atmega AVRs. Some examples:

Marlin on a 16 MHz 8bit Atmega can only run the stepper interrupt at 10,000 hz without bogging down the processor and blocking other critical algorithms (like motion planning). It can fire step rates up to 40,000 hz by pulsing the step line two or four times per interrupt, which effectively drops the microstep level in software and runs the motors rougher/louder.
Repetier on the same Atmega can run the stepper interrupt at 12,000 hz, because it is optimized more for execution speed than Marlin.
Repetier on an 84 MHz 32bit ARM Cortex-M3 can run the stepper interrupt at 80,000 Hz.

These limits typically only affect actual stepper speed when relatively fine microstepping is used. Consider an example based on a very typical Marlin printer configuration. Microstepping of at least 1/4 is strongly recommended to avoid resonance issues, so let's start with 1/16 stepping. This allows quad-stepping to effectively output 1/4-steps. Starting with finer microstepping will drop our top speed, and coarser microstepping will be louder and may encounter resonance, so this is a good starting point. Then asssume a typical 32mm-per-rev pulley on a 1.8 degree (200 steps/rev) stepper motor. This system has a resolution of 200*16/32= 100 steps/mm. At 40,000 Hz total stepping rate (quad-stepping at 10,000 Hz) we can theoretically travel at 400 mm/s before hitting Marlin's hard cap. That's probably going to be a higher RPM than we want to run the motor anyway, so it's not a very impactful limit.
In comparison, if we started at 1/128 stepping (such as with the THB6128 driver chip) our top speed with 8bit Marlin would be 50 mm/s. That's quite slow.
Firmware motion planners can further limits motor speed by ramping up and down to traverse turns and corners. If the model geometry has lots of sharp turns, the target speeds commanded by the gcode are likely to never actually be reached. Only long, straight line paths will have enough ramping time to hit the speed target. You can see this yourself by printing a very small model at a variety of feedrates and timing the actual print duration: at a certain point, increases in the commanded speed will make no difference on actual print times.
Another constraint some firmwares enforce is requiring the ability to safely decelerate to a stop within the length of all the motion commands in the planner queue. This allows the printer to gracefully handle a sudden loss of input, such as as if the host computer stops transmitting USB commands, or if the SD card experiences a series of read errors. If the printer just abruptly stops from full speed when it runs out of commands, it is likely to lose position and ruin the print. Whereas if it can decelerate to a safe stopping speed, it may be able to resume after the command stream resumes.
In terms of actual motor behavior, the inductance and back-EMF introduce significant limits because they decrease motor torque at higher RPMs. This produces a torque/RPM curve that drops off at higher speeds:

http://www.geckodrive.com/support/step-motor-basics.html
Note in the picture that there is a flat "constant current" region on the left side at low speeds. This is the range where the chopping driver is limiting coil current. On the right side of the curve, current is not able to reach the target before it must be switched back off for the next step. That reduces field strength and thus torque.
There are two separate effects to consider here:

Motor coils are inductors, which means there is a first-order lag between applied voltage and coil current. A standard bipolar stepper motor with a microstepping driver must raise the coil current from zero to max or from max to zero every full step (eg every sixteen 1/16th microsteps). At high step rates, there is not enough time to fully charge the coil to its max current before the next step requires dropping the current back down. Without developing full coil current on each step, torque is lost.
Every motor is also a generator, and spinning the rotor generates back-EMF voltage within the motor coils. That voltage waveform gets overlaid on top of the drive voltage waveform with a phase shift dependent on the rotor position relative to the coil energization position. In simple terms, this voltage attempts to brake the motor: it always does whatever will slow the motor down. This means it opposes the applied drive voltage when the motor is applying forward torque, or assists the applied drive voltage when the motor is applying brake torque.

For a practical discussion of speed limits, we can simplify the situation by assuming back-EMF voltage opposes the drive voltage applied to the coils. This means there is less effective voltage raising/lowering coil current, and it takes longer for the current to change, and less coil current is developed than would be the case without back-emf. This further depresses the torque/RPM curve of the motor. And when the back-EMF voltage is around the same magnitude as the drive voltage, significant motor instability can result because of complex feedback effects between rotor position and effective coil voltage.
You can play with these effects using different motor configurations and speeds for a few popular 3D printer stepper drivers using my stepper driver simulator: https://github.com/rcarlyle/StepperSim
In closed-loop applications with position feedback and high-end drivers that can damp various instability modes, it may be ok to run the stepper all the way down the torque curve at very high RPMs. In more typical open-loop 3D printer applications, it's generally best to stick to the low-RPM part of the torque curve before inductance and back-EMF really take over the motor behavior. Losing too much torque can easily mean skipping steps and losing position, ruining the print.
Another important effect for steppers is mid-band resonance. This is not a normal mechanical resonance, but actually an electromechanical resonance effect. It's quite complicated, but the short explanation is that a stepper has an intrinsic 90-degree phase shift between position and torque, and when speeds rise to a point where coil inductance introduces an additional 90-degree phase shift between coil current and applied voltage, the electromechanical system has a highly-unstable 180-degree phase lag and thus creates a negative feedback loop. This can rapidly drop motor torque until the motor loses synchronicity with the driver's applied voltage and stalls.
Mid-band resonance only occurs when coil current is limited by inductance. It cannot occur in the constant-current drive range because there is not enough phase lag between applied voltage and coil current.

http://www.geckodrive.com/support/step-motor-basics.html
Unfortunately, measured torque curves available from manufacturers almost never show resonance zones, because the curves are produced by loading motors with friction-brakes that damp any kind of resonance effect from building. Whereas a 3D printer drivetrain load is almost entirely inertial (accelerating a mass) which is much more prone to resonance.
High-end drivers can automatically detect and damp mid-band resonance, but typical low-cost 3D printer drivers do not have this capability.
It is generally prudent to avoid entering an RPM range where mid-band resonance may occur. This is easily accomplished by sticking to the left side of the torque curve, in the constant-current operating region. This ensures high torque and good stability.
For a concrete example, consider the popular Kysan 1124090 stepper with a 24v power supply.

https://ultimachine.com/content/kysan-1124090-nema-17-stepper-motor
To maintain high torque and avoid mid-band resonance, we would want to keep the RPM to about 400 or less. For the same 32mm-per-rev pulley mentioned above, that would limit speeds to around 200-240 mm/s. Higher speeds are possible, but may encounter reliability issues.
This speed, of course, assumes a 24v PSU is used, to match the measured torque curve: a 12v PSU would have a significantly lower top speed before inductance starts to limit coil current, around half as fast. Higher supply voltage greatly increases the top effective speed for the motor.
Again, you can easily simulate this effect (using https://github.com/rcarlyle/StepperSim). This simulator output chart shows how inductance and back-EMF are keeping coil current from reaching the target:

For practical drivetrain design, a motor/driver simulator is really the best tool in the toolbox for finding the point where performance will start to degrade due to inability to hit current targets. It's simply too complex to apply simple equations or rules of thumb with any accuracy. These electrical effects and the firmware step generation limits are likely to be the two main restrictions on motor speed for most printers.
Of course, how fast you can melt plastic will tend to limit printing speeds significantly below the true motor speed limits, but that's a different discussion. For the moment, we can simply say that top motor speed tends to be unimportant for print moves in typical Cartesian printers. However, there are a few instances where they are likely to drive printer performance:

Linear Deltas, where carriages may need to run several times faster than the effector for certain move directions
Geared extruders with high reduction ratio (eg much over 5:1) for high retraction speeds
Short-pitch lead screws (or all-thread) that need high rotation speeds to achieve moderate linear speeds

This answer is epic. The link to the XLSX calculator as well! I was going to ask a question about repurposing my old stepper, after putting the values in the XLSX I got my answer already.


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Practical concerns smoothing PLA print with chloroform vapours
One way to give PLA prints a smooth finish is treatment with chloroform vapours (or other solvents, as mentioned in this answer). This method is even featured on Ultimaker website. I would like to try it on some of my prints.
What are the practical concerns I should be aware of using chloroform vapours? I am looking for advice concerning vaporisation temperature, time of exposition that makes for a nice finish, and any other experiences.
Caution!
Chloroform is a moderately toxic chemical! I only approach this method as I have an access to a well-equipped chemical laboratory with a fume hood.
Disclamer:
The question is not about the safety issues using chloroform vapours. It is about how obtain the best post-processing results with least trial-and-error.

This Reddit post seems to have some good trial and error dialog.
This Thingiverse post, along with many other references online, suggest that the results are very similar to that of an Acetone treatment with ABS. I'm not familiar with the inner workings of how it works, but the general advice is to be conscious of what you're working with. A heat-induced vapor treatment seems to yield the best surface finish, but can be tricky to track down proper exposure times. It seems that the time required to achieve a desirable surface finish depends on the size and openness of the features on the object. By openness, I mean how evenly the vapor is able attach itself to the surface of the object as compared to other features. Some this variability may be reduced by streamlining the process. Perhaps if you found a way to rotate either the part or the vapor container during the process. This could ensure contact is made in small corners/features. Other variables to consider may be:

If a gradual reduction of exposure is necessary (as is with most heat treatment operations);
How much temperature effects time. Most pages I've read mention 100C as the temp to vaporize the chemical;
Size of the "vaporization chamber" in accordance with how much of the chemical is available. I've used a gallon paint can lined with lightly dabbed paper towel with Acetone for part between 1"^3 to about 4"^3.

That's all I can think of, currently, that could potentially have the most impact on the process. Just as with 3D printing, there's not an easy way to definitively know how your parts will turn out. The sheer difference in the shape of your parts could throw out any "proven process" you come up with. Hopefully this gives you an idea of what things to look out for in starting out.
Here's information about safety, before OP added disclaimer
As with any chemical, always refer to the MSDS (Material Safety Data Sheet)! Whichever supplier you acquire the chloroform from, should ship an MSDS with the product. If one is not shipped, you should be able to request one. If they don't have one, don't use the product and don't purchase from them.
In most cases, you can get away with finding any MSDS online, but I'd recommend trying to get one directly from your supplier as they might theoretically have a different "strand" of the chemical. Therefore, reactions and safety precautions may be different than what you will find online.
A quick search yields this MSDS which states that chloroform does have "carcinogenic effects" along with some other long-term, undesirable effects. As with any other MSDS it continues to go over best-practices and extremity limits.

The mentioned Reddit post indeed has some useful info! Thanks for sharing MSDS and safety concerns, but that is not the information I am looking for. I asked about practical processing tips like exposure time, evaporation temperature and so on. I have higher education in chemistry and can handle chemicals safely, no worries :)

Sorry about that, I'd rather include the "no-brainer" type content for the poor sap that forgets something as important as the MSDS lol. I'll keep poking around, I found a few Google Group pages talking about it in my quick search. You might also try searching the forum pages on 3DHubs website. The peer-based printing service has some post-processing articles floating around.

Beside vaporizing with heat, you can use an atomizer and do cold vapor. The time is around 1-5 minutes at 45ºC for a 10x10x20 mm piece like a Marvin or a bot. I have done only gangster tests with it, so I have no larger piece info.
Passive vapor polish does not work with chloroform since it tends to crack. It needs a fast flash on the outside only.

authors: پرینتر سه بعدی


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How are delta movements calculated?
On a Cartesian printer movements are really simple. If we assume the printer has 100 steps/mm on each axis, then a move of 10mm on a axis is just 1000 Steps on that axis.
Movements that are not aligned with one axis are also simple. Moving from x,y = 0,0 to 10,10 would be 1000 steps on x and y.
On deltas even for simple moves more than one motor has to move. And just calculating the amount of steps on each axis needed to reach the destination probably gives a curved move.
So what is the algorithm to calculate the steps for a given move for a delta printer?

This seems to be solely a theory question which might be more appropriate for a site that deals with programming and/or mathematics as how the firmware works internally is irrelevant to the use of a 3D printer. On the other hand, the question is specific to 3D printing and might be relevant to somebody trying to modify or tweak their printer's firmware.

There are two main special steps to the technique used by most open-source 3d printer controllers:

Divide each linear gcode segment into lots of very small subsegments ("Segmentation")
Use some basic trigonometry or the pythagorean theorem to tie extruder position to carriage height for each of the three towers ("Inverse Kinematics")
to find the target position for each small segment

The inverse kinematics are surprisingly simple. A virtual 90 degree triangle is constructed from two known lengths to solve for the unknown third length:

The fixed delta arm length is the hypotenuse of the triangle
The horizontal distance between the column joints and end-effector joints is calculated from the XY coordinates of the nozzle and the fixed position of the column, to determine the length of the lower side of the triangle
The length of the upper side of the triangle is calculated from the previous two via the pythagorean theorem
The length of the upper side is added to the nozzle Z height to get the necessary carriage height

I think the best open-source reference here is Steve Grave's Rostock Kinematics document, rev3 available for download here: https://groups.google.com/d/msg/deltabot/V6ATBdT43eU/jEORG_l3dTEJ
Some relevant pictures:

These inverse kinematics calculations are performed for each carriage to get a "carriage space" target position, and this is performed for every path sub-segment.
The results from these steps can then be reinserted back into the standard linear path interpolation techniques for the printer, in which it fires steps in the necessary ratios and at the necessary rates to produce the desired straight-line motion and acceleration/velocity profile. (How THAT is done is a different question.)
The net effect is that the printer will move through a series of small "linear" carriage movements (linear meaning constant* speed with respect to time) that collectively approximate the necessary curved (quadratic position with respect to time) carriage motions required to produce a straight-line end-effector move.
*(Constant speed before acceleration slowdowns are applied in order to obey dynamics constraints, anyway. Again, that's the subject of a different question.)
Segmentation is very similar to the process of using a polygon to approximate a circle. If the facets are small enough, the polygon is a good approximation. Higher Segmentation rates produce less path-following error.  The primary conceptual difference between drawing circle arcs and Delta motion paths is that the so-called "faceted arc" with Delta Segmentation is constructed in height-vs-time coordinates instead of the X-vs-Y coordinates you'd use to draw a circle on a computer screen.
This system is used in large part because support for Delta style printers was originally bolted onto GRBL-based motion planners which were written exclusively for straight-line motion paths in Cartesian printers. It was a relatively minimal modification to the existing codebase compared to implementing full quadratic path interpolation.
Techniques have evolved over the years. And alternate approaches are often used: for example, the dc42 fork of RepRapFirmware performs exact path-following without segmentation, by recalculating the proper time for the next step after every step. This is functionally equivalent to approximating a circle with a polygon facet count so high that every pixel on the screen gets its own facet. So it is exactly as accurate as the positioning resolution of the motors allows. The downside is that this segmentation-free technique is fairly processor-intensive, so it only works on relatively fast controllers, not the older 8bit Atmega AVR that powers most existing consumer/hobbyist printers today.
Other techniques are possible. The academic parallel robotics control literature is a whole other world of mathematical techniques and complexity in order to produce generalized control algorithms that work for a wide range of robot mechanisms. The version we use in open-source 3d printers is quite simple and application-specific in comparison.

I am describing how this is done in the Marlin firmware.
The first step is to split a linear movement from (x, y, z) to (x', y', z') into many discrete segments. To this end, the amount of time the move would take at a given speed is calculated, and the value delta_segments_per_second is used to calculate the number of segments used.
This is done in the function prepare_move_delta in the file Marlin_main.cpp. The endpoints of each of these segments is then passed to the function calculate_delta:
void calculate_delta(float cartesian[3]) {
    //reverse kinematics.
    // Perform reversed kinematics, and place results in delta[3]
    // The maths and first version has been done by QHARLEY . Integrated into masterbranch 06/2014 and slightly restructured by Joachim Cerny in June 2014

    float SCARA_pos[2];
    static float SCARA_C2, SCARA_S2, SCARA_K1, SCARA_K2, SCARA_theta, SCARA_psi;

    SCARA_pos[X_AXIS] = cartesian[X_AXIS] * axis_scaling[X_AXIS] - SCARA_offset_x;  //Translate SCARA to standard X Y
    SCARA_pos[Y_AXIS] = cartesian[Y_AXIS] * axis_scaling[Y_AXIS] - SCARA_offset_y;  // With scaling factor.

    #if (Linkage_1 == Linkage_2)
      SCARA_C2 = ((sq(SCARA_pos[X_AXIS]) + sq(SCARA_pos[Y_AXIS])) / (2 * (float)L1_2)) - 1;
    #else
      SCARA_C2 = (sq(SCARA_pos[X_AXIS]) + sq(SCARA_pos[Y_AXIS]) - (float)L1_2 - (float)L2_2) / 45000;
    #endif

    SCARA_S2 = sqrt(1 - sq(SCARA_C2));

    SCARA_K1 = Linkage_1 + Linkage_2 * SCARA_C2;
    SCARA_K2 = Linkage_2 * SCARA_S2;

    SCARA_theta = (atan2(SCARA_pos[X_AXIS], SCARA_pos[Y_AXIS]) - atan2(SCARA_K1, SCARA_K2)) * -1;
    SCARA_psi = atan2(SCARA_S2, SCARA_C2);

    delta[X_AXIS] = SCARA_theta * SCARA_RAD2DEG;  // Multiply by 180/Pi  -  theta is support arm angle
    delta[Y_AXIS] = (SCARA_theta + SCARA_psi) * SCARA_RAD2DEG;  //       -  equal to sub arm angle (inverted motor)
    delta[Z_AXIS] = cartesian[Z_AXIS];
}

This function takes care of the delta geometry and calculations needed to convert the (x,y,z) coordinates of the segment endpoints to corresponding positions for the carriages. The translated coordinates are then passed to plan_buffer_line, which calculates the steps needed for each stepper motor and actually makes these steps happen.
The exact kinematics used in this function are explained in much more detail at the Marlin github.
What is important to note is that plan_buffer_line moves the carriages linearly, and the printhead thus describes an arc and not a straight line. A straight line move is thus approximated by many small arcs.

The code is hard to read.What is SCARA? Could you describe the steps that the code implements?


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Scalable 3D Printer
Is there a definitive scalable 3D printer?
I've seen examples of Chinese companies printing entire houses, and I'm curious as to printers / filaments that are intended (or at least able) be scaled up for (very) large print jobs.
Since most hobby printers can take hundreds of hours for something that can still be held in our hands, so I'm curious if there are any designs for printers that are meant to extrude material efficiently with a easily scalable printing area.
Open sourced / free is preferable; though I'm interested in any designs that exist, commercial included.

I've tried to answer your question, but it is technically too broad and doesn't have much direction. Please consider updating your question with some of your own findings to help narrow the possibilities.

The 3D printed houses I've seen are printed with concrete, and use entirely different equipment than what you see in a typical desktop 3D printer. A layer is usually about an inch thick or more. Scaling your 3D printer up to twice its size is usually reasonable, but 10x the size is not.

One big challenge with scaling anything up (or down), is that not all properties or characteristics scale linearly.
Consider a trivial case: a small cube. If you double the size, you've quadrupled the surface area and octupled the weight.
If you take a desktop-sized 3d printer design, and just double the size, it will weigh 8 times as much. But all the bolts holding it together are only 4 times as strong. So weight-bearing bolts are effectively under twice the strain (per unit of cross-sectional area); the exact factor depends of lots of things (orientation, leverage, etc).
If you scale up by 10x, they'll potentially be under 10 times greater stress, and probably snap.
Many, many parts will have similar issues: Drive belts that are twice as wide and twice as thick will still have 1/2 the (relative) strength -- and stiffness for the motors to overcome.
The stepper motors have to move 8 times the weight, and you'll want them to move far, far faster. But steppers lose torque when you spin them faster.
My main printer is pretty much a MendelMax 2, but the Y axis is about 6 times bigger (X and Z are normal). On MM2 the whole build platform moves along Y -- on my printer it weighs far more than on a regular-size MM2 -- it's 6 times the mass just because of size, besides that it has to be much stiffer to avoid sagging over that distance. I went to a larger motor, but it could still barely move the axis. I eventually got it to move at pretty normal speed, but to print long objects it really should be 6 times faster or so.
That would require an amazing motor -- and really big electronics to drive it.
Another challenge is the printing material -- 20mm diameter PLA fiber would be really impressive, but a little hard to find, and a spool would be hard to lift. The power needed to melt it fast enough would be impressive, too. Bridge and house printers I've seen in reports, use pumped concrete through about a 100mm wide nozzle (I have no idea what the nozzle is made of, to stand up to the abrasion). See Watch this giant 3D printer build a house for some cool pictures and video.
Scaling up is a fascinating project -- but it's harder than it looks.

+1 For a great answer! I didn't think to include design theory. I think that will help newbies to conceptualize the importance of a good machine design.

I forgot to mention that getting a house separated from the blue painters' tape when you're done, might be tricky. :)

If I understand your question correctly, it sounds like you're looking somewhere within the RepRap realm. The RepRap community is mostly responsible for the boom in consumer 3D printing in the past 10 years, and that's most likely because it's open source. RepRap designs are mostly dynamic (and most parts can be 3D printed), so you could theoretically build a larger frame for your machine and use a slicing engine that allows you to set the build volume. I believe Slic3r allows you to customize the build space, I'm not sure though.

As far as I know, right now, all the "3D printers" that can print houses, bridges, etc. are experimental models (and sometimes, vey elaborate art projects) - they just don't exist except as one-off creations designed as a proof-of-concept showing this can be done.
Maybe some of those project published their plans and code but they are not designed for mass production or general use, even if you manage to build another copy of one of them it will probably be able to print just the same project the original printed.
You specifically asked about speed, material and build area:
Speed: the speed really depends on the size of the printer's nozzle, the typical desktop printer has a 0.4mm nozzle, if you replace it with a 1mm nozzle the printer will be approximately twice as fast (1.25 nozzle area vs 3.14 nozzle area, assuming you have an hotend designed for larger nozzles that can melt the plastic fast enough).
Now, the "house printer" does not use a standard desktop hotend (see material below) and buildings don't have fine details so you can make the head much larger.
However, as far as I know the early prototypes are still much slower then conventional construction methods.
Material: houses are typically not made of plastic, the printers I know of have welding equipment instead of an hotend and extrude steel
There are probably other methods but I bet all of them use typical construction materials such as steel and not thermoplastic.
Size: and last but not least, it's obviously not practical to build a printer with as house sized platform, the house printers are actually relatively small robots that travel across the construction project, leaving material behind them and then climb over the previous layer to print the next part.

Have to disagree on the nozzle speed numbers, there are two different things that are more important than diameter: 1) AREA of the nozzle orifice, and 2) how fast the hot block can transfer heat into the filament to melt it. You can't push solid filament through the nozzle, the melt speed is really the limit for most consumer/hobbyist printers using nozzles over 0.6mm or so.

@RyanCarlyle - you are right, it's the area, not the diameter. and for large nozzles you need an hotend like the E3D Volcano that can actually melt the plastic fast enough


text:
Why won't makerbot accept an STL file from Blender?
Our library system just put a 3D printer in one of the branches. I have used SketchUp on the library computers for a number of years just to do artsy things. Suddenly, I have the opportunity to actually print something. (I'm really not sure why the libraries have SketchUp installed. But, I have enjoyed using it.)
There is a plug-in available for SketchUp so that it can export STL files. But, the security on the library computers will not allow me to put a file into the SketchUp plug-ins folder. And, the tech guy at the library doesn't think that the IT guys at the library will update all the copies of SketchUp at all the branches just so someone could do 3D printing.
After doing some searching on this website, I found out that I could export a COLLADA / dae file from SketchUp. I would then import that dae file into Blender (The portable version on my flash drive). I could then export it as an STL file.
The process appeared to work. I could see my test object in Blender.
I gave the STL file to the branch manager who tried to open it in the Makerbot software so that it could be sent to the printer. But, it gave him a message about the file not being recognized.
I am not familiar with all the details in the importing and exporting processes that are going on. Is there someone out there that can give me some help?
One problem is that, I am using the library computers. I cannot alter them. I can use what portable versions of software are out there, like Blender.

Have you tried installing SketchUp on your flashdrive? There is a free version available

If you are able to, can you post a download link for the stl file?

If they are going to offer 3d printing capability, it seems like there would be a convincing argument for having at least one of their public computers configured to export to it.  Perhaps the one physically closest to the printer or the office of whoever accepts files?

Here is what I suggest you try. If you have a file that you can view/edit in blender I would export it as both STL and OBJ formats. Then take those files and upload them to Netfabb (https://netfabb.azurewebsites.net/) and get a "repaired" file. Have the library try again with the repaired STL and OBJ files. If this doesn't work try to get the exact error message/dialog that the makerbot software is giving them as well as the version of the software that they are using.

We tried your suggstion.:MakerBot error message reads "This file could not be loaded. It may be an unsupported file format."
Netfabb error message reads
""Failed could not load mesh. (invalid .STL file)"

Okay that indicates that it is almost certainly an issue related to the translation of the file. Did you try with an OBJ file as well? I made a quick box in SketchUp, imported into Blender, Exported the STL and then when I imported it into Netfabb, I got the same error. I tried the same process and when I exported an OBJ it was accepted by Netfabb. Try this and let me know what you find.

Sounds like Blender's STL output has issues?

@RyanCarlyle I think it may have something to do with the Sketchup -> DAE - > Blender - > STL workflow. I have great success exporting STL files from modified OBJ/STL as well as native blender formats. It just seems like this is one of those weird combination of things that doesn't seem to work right.

It's strange, because an STL is pretty much just a list of triangle vertices with minimal metadata or encoding, and Makerware/Desktop is usually pretty tolerant of typical mesh issues like flipped normals. (It will load them, anyway.) Is blender outputting a binary or ascii STL? Maybe ascii would work if that's not already what it's using?

@RyanCarlyle You are right. I went ahead and went through the above process and when I exported my STL from Blender I selected Ascii and it succeeded in Netfabb. I can't test it in Makerware but I can only assume it would behave similarly. It still doesn't quite make sense that a binary STL works when it is created from a Blender file but not from a DAE. A real head scratcher... At least we have a solution for those that have a slicer that can't handle OBJ files.

OK - So, I had to leave and come back. Thanks for all the comments. No. I did not try an OBJ file. But, as soon as I was driving off I realized that there was some message about the file being too small when we tried to use the MS netfabb website. So, a little light went on in my head. When I returned, I opened the Blender file and scaled it up in two new files. I was able to fix them with netfabb. So, I will now give the files to the tech guy in the library. It is my unfamiliarity with Blender that caused this. I have only dabbled with it, unlike SketchUp. I will let you know what happens.

Thanks to all. The tech guy in the library was able to open the STL file with the scaled-up Blender objects with makerbot. It was still tiny when it was opened. But, he was able to scale up the object more and set the exact dimensions in makerbot. So, even though this is a long process, it seems to work. We didn't print the object. It was just a test file to get the process working.

Makerbot will accept obj files also.
Is there an error while importing the obj file?
Also you can see errors of your imported file in your makerbot
It will be marked in black.

Please make sure your object is a watertight mesh. As I have seen its easy to make a surface model in sketchup. A 3D Printer cannot print something in surface.
You can also try importing to netfabb to check if the part has errors in it.
If you want a better modeling software, I suggest you to check out OnShape.
Its a cloud based cad software. Its free as well. (10 private files, beyond that everything is public. 100$ per month i think)
www.onshape.com


text:
How to remove white marks from PLA
When you cut or break a PLA model (for example to remove support) it often leaves an ugly while mark where the removed piece was connected.
Sanding also tend to leave dull white scratches on the sanded surface.
What can I do to restore the white areas to the original filament color?

As suggested by Ryan Carlyle you will need to use heat to reflow the plastic. However I recommend against using a heat gun as generally you want a very concentrated small area to be heated.
I have had great success in using a soldering iron with the tip placed close to (but obviously not touching) the problem area. Keeping within about 3-5mm has very good results, is easier to control and position. This limits the impact to the surrounding areas and can let you get into small crevices etc.
Just be careful not to touch the part.

A quick blast from a heat gun will very slightly reflow the surface texture and eliminate white marks.
However, it's important to avoid over-heating the perimeter layers or you'll see them soften and sag into the infill. So wait for the heat gun to get fully hot and then use a short duration of high heat. Let the part cool between attempts if you don't get it all the first time, or need to clean up a large area.
Incidentally, the heat gun will also help clean up strings from travel moves.

+1 for the good answer. Please note that the area needs to reach the minimum melting point to effectively clear the affects of a failure mode.

I have had success in 2 ways. After sanding, a little polishing with oil (vegetable oil is fine) will help to bring the colour back. If the oil gets cleaned off however you get back to the whitening again.
I'm also a a big fan of the reheating. It works on ABS too. I haven't used a heat gun though, only an open flame. I have had success with a lighter, and with a cook's blowtorch, this way you can be very localised in where you heat, but you need to be VERY brief. With a lighter just flicker the flame over the area concerned; with a blowtorch, start from far away and move the flame in and out of target until you see the whitening start to go.
A little practice on a part that is not too important would be prudent, and please be careful. I take no responsibility for you burning yourself :).

I've also had success with oil. I simply apply a drop of the 3-in-one oil I also use for lubricating printer components. Not sure why it works, but it does (I initially tried it on a hunch). If someone understands the principle behind it, they can perhaps come up with a more effective solution.

+1 for lighter. Just an additional remark, get the lighter very close to the surface. You want to heat surface very fast so that it will smooth/recover color before the heat is dissipated to underlying layers and cause softening of the part.

For PLA, white marks disappear at just over 60°C. A warm water bath works great, as does holding it over boiling water (use tongs!)
My favorite technique is to hold the part with tongs and wave it in front of the steam from a boiling tea kettle. It takes no more than a second, so you can do this on a dozen parts in rapid succession.
If you do this quickly, the plastic won't even soften noticeably; the white marks should disappear instantly.
If you don't want to get it wet, a heat lamp should also suffice. Holding it over a toaster for a second should work too. PLA gets soft at such a low temperature there's no need to use a heat gun, open flame, or soldering iron.

I've had amazing results just rubbing in a very small amount of vaseline. It makes the white marking virtually disappear.
I found this trick after printing a recorder for my son. I sanded the connecting tubes to help them fit better, and used vaseline there also for fit, but mainly to help seal the connections to prevent air loss. I was amazed to see the white marks disappear completely.
I don't have before pictures of the recorder to demo the effect, so here it is again using our old friend Benchy.
First, the original print, where you can just see some less-than-perfect results on the overhang at the base of the bow (sorry, my cell phone camera isn't that great)

Next we have the same part, after some sanding to smooth the section:

Note I have already wiped away as much white powder as I could. If this was something I cared about, I'd sand it more evenly across the entire hull, rather than just this section.
Finally, the same part again, after I've rubbed in some vaseline. In this case, what I actually had to hand was a small container of Carmex, but it worked just as well.

Again, my camera sucks... but you can see the important stuff: there's no white marks. It only takes a very small amount of vaseline to clean a fairly large area.

Note that on lighter colours these light scratches can be hard to see. On white PLA they're almost invisible unless you hold it against the light at an angle and look at the specular reflection.
I've had some luck on a flat surface (the face of a game tile I printed) by going through various grades of sand paper. 240, 600, 1000, 2000. Finally, finishing with a regular metal polisher like Brasso brings up a shine that doesn't seem to wash off, unlike vaseline/vegetable oil.
It's quite a lot of work though, and even more work on curved surfaces. If heat treatment works for you, it may be preferable.


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Cura not allowing full print area to used
Cura does not seem let the full print area to be used. My printer is a Lulzbot Mini. The design illustrated below can be found here.

Cura is likely factoring in your skirt. Change the skirt lines to 0 and you might be able to print (Expert -> Switch to full settings, then click the options button next to "platform adhesion type."). Cura also seems to have an in-built build size offset of about 2 mm. I can't seem to get rid of it in any way other than to change the build size.

The same happens in MakerWare with a skirt and/or raft

Click the button next to the dropdown. You will find options for the skirt there. A skirt is not counted as a "platform adhesion type," apparently.

Setting "Start distance (mm)" to 0 fixed it.  Thanks!

@Kevin: What do you mean by "in-built build size offset"? Does Cura change the size of a print? Or the position?

As in, Cura's actual computed print space is smaller than appears on the screen. Cura will change the color of objects that are larger than your print  space and not slice them.

Changing build size does enlarge the printer volume (but not the actual; it is shifted by half the enlargement in X and Y), but, note that this doesn't help for your printer unless you change the X and Y offsets to the end stops as well! You can simply redefine this with G92 in a start-script for instance.

If you set skirt setting to 'none', it will get you up to full bed area -1 mm at the edges, so, for example, 198x198 instead of 200x200.
You need to go to 'Travel' and set 'Travel avoid distance' to zero to get the full 200x200, or whatever, bed area.


text:
Is Arduino Due a worth buy as controller electronics for deltabots?
Over the times I hear people saying delta inverse kinematics push atmega2560 to limits. I see in my local supplier Arduino Due and RAMPS-FD is the cheapest 32bit alternatives. But there's not much documentation on it so any opinion or personal experience are welcomed.

is it really 2560 based electronics so laggy that printing quality is compromised?
does Marlin4Due has a good support for auto calibration?
anything else to caution against besides a ramps1.4 is a no-no?

(I'm planning my first delta. 2560 seems to work perfectly with my previous xy bots though. )

An 8bit Atmega can provide bare-bones delta performance with Marlin (eg 40mm/s print speed) or pretty good performance with Repetier (due to more optimized algorithms). For a small and simple delta like a bare-bones Mini Kossel, 8bit may be fine. If you want to do high-speed printing or use any of the fancier features, you should go with 32bit.
The big issue with 8bit comes up when you want to do something that taxes the MCU. Delta kinematics already add a lot of extra math on top of all the normal printer functions like command parsing, motion planning, and heater control. For example, adding any of these to an 8bit Delta can cause issues:

Bed tilt compensation "auto-leveling" -- the coordinate space rotation transform adds a lot of extra floating point calculations to every movement segment. That really taxes the 8bit Atmega since it does not have native floating point support. (Note that pre-print auto-calibration such as in the RichCattell Marlin fork is not the same as bed tilt compensation and does not add any run-time processor load.)
Full graphics LCDs -- refreshing the LCD screen for animations and status reports takes a surprising amount of horsepower. 8bit Marlin is widely known to suffer from stuttering and print quality issues when running a GLCD on a delta.
Highly faceted (smooth) curves, particularly over USB -- the high rate of gcode command processing sucks up a lot of clock cycles, particularly in firmwares that run USB comms as a top-priority interrupt.

What the Due (or other 32bit board option) does for you is de-bottleneck the MCU so you can push the printer harder or utilize features that add processor load. Here's why they're so much better:

In simple clock speed terms, the SAM3X8E in the Due/Duet/Alligator/etc is about 5 times faster than the Atmega 2560, and the LPC1769 in the Smoothieboard/MKS-SBASE/etc is about 7 times faster. But they're actually MUCH higher performance than clock speed alone would suggest, because the 32bit architecture and native floating point support mean far fewer clock cycles are required for complex calculations.
They also have more RAM, meaning the the firmware can manage more features and look farther ahead when motion planning.
They also have more program space, meaning the firmware can, if desired, be compiled as a single full-featured build that covers all possible printers (as RepRapFirmware and Smoothieware do) and thus end-users don't have to edit and compile code in the Arduino IDE to configure the firmware. The Atmega line requires hundreds of conditional compile statements in the firmware to exclude unused features from the binary to get the memory footprint down.

All that said, the switch from an 8bit Atmega AVR to a 32bit ARM Cortex-M3 is still just an upgrade from a late-1990s processor to an early-2000s processor. Neither is "modern" by any stretch. (For example, the BeagleBone Black used by Redeem and MachineKit utterly blows away the Due in processing power and memory. But those options have steep learning curves at the moment.) The Due can still be bogged down by printing very fast with lots of features enabled. It's a big upgrade on an Atmega, but I predict it's going to be replaced by much faster controllers within the next few years. Announcements of upcoming next-gen controller boards are already trickling out.
To summarize, the answer is yes, a Due-type board is a good buy if you want a high-performance printer. It will meet 99%+ of user's needs today. But it will be replaced in a few years, just like the Atmegas are being replaced now.
As for specific Due shields, I strongly recommend NOT going with RAMPS-FD. It was cloned for sale by Asian companies before the design was finished, which seemingly caused the original designer to abandon it before working out all the bugs. RAMPS-FDv1 has some nasty design flaws such as heaters turning on while flashing firmware. RAMPS-FDv2 is better, but can experience unreliable and oddball behavior due to unresolved issues in the circuits intended to make it compatible with both 3v3 boards like the Due and 5v boards like the Mega. (For example, the thermistor voltage reference circuit needs modifying to work right, and there appears to be timing issues in the 3v3-5v level shifters.)
RADDS is a good Due shield. It is a simpler, more reliable, more compact version of RAMPS-FD. It is very popular in Germany and has recently (late 2015) become available for sale in the US.
I also recommend purchasing the Due R3-E instead of the regular Due R3. Anecdotally, the "E" version appears to eliminate some firmware bootup issues that can occur when the board is first powered at lower than nominal voltage.
One possible downside to the Due is that Arduino just announced they are no longer manufacturing it. So all new Due boards from here on will be made by 3rd parties. That's not necessarily bad, since it's open source and many other companies will surely continue making them, but there won't be any more made by Arduino.
For single-board options using the same SAM3X8E processor as the Due, the Duet 0.8.5 is becoming quite popular. (It runs RepRapFirmware, which has some great Delta features.) The Alligator runs Repetier. There are several other beta/experimental/development boards in the works too. The community appears to be moving towards the Due and Due-compatible boards over the other various options.

I have very limited choice for lack of local supplier. I can only find ramps-fd. Is there a way to distinguish between the premature clones and the newer ones?

There is no "off the shelf" fully working RAMPS-FD board available, to my knowledge. The companies I see selling them (eg Geeetech) are well-known for cloning designs for sale direct from open source files without actually testing if they work. I hate to say it, but you're probably better off with an Atmega/RAMPS running Repetier than with Due/RAMPS-FD.