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How to stop objects with "floating" parts from breaking
So, I'm having this problem where almost anything I print with a section(s) that is not directly connected to something below it breaks when I try to pull the small filaments meant to hold it up during printing off. For example, I 3D-printed a Rayquaza(this one) from Pokemon for my little brother, and as I was carefully pulling the filament from under the mouth, the whole head just snapped off. Does someone have a recommendation as to a way to get the small filament off without breaking the object? Would a solution just be to print it bigger and see if it holds up better, or is there something else I can do? Thanks.

As an answer says: never pull off supports. Always cut or melt to minimize stress on the part.

I don't think I could produce enough heat to melt them, and if i did it would probably melt more than i wanted it to. If I cut it, it might end up going wrong and cutting a piece I wanted off if I'm not careful.

The small filaments you remove that hold the parts up are called supports. The one model I located on Thingiverse clearly requires a number of supports, as the model is not easily designed for 3d printing with FDM printers. It would be better printed with SLS, but that's not the focus of your question.
You don't specify how large you printed the model, but certainly a scaled-up version will be stronger at the weak points. You will want to use sharp non-shearing cutters to clear away as much of the supports as possible, without torquing on the model.
Another option which also reduces the forces on the model body is to use a soldering iron to smooth and clear/cut the supports. If you are able to use cutters and not damage the model, the soldering iron can remove and flatten the remnants of those supports.
Please note that if your careful work has resulted in a model that snaps to pieces, your little brother will soon destroy the successfully cleaned up model just as easily.
If you have skill with 3d modeling software (Meshmixer and Blender come to mind for such organic models), you can add insignificant items to the model to provide functional support. Would the Rayquaza look fiercer if you 3d printed a cage as an integrated part of the model, using the bars of the cage to provide support?
I successfully printed a model that was created by an artist unfamiliar with 3d printing restrictions. The support material was wash-away PVA. I provided the model to the "owner" who washed away the support material and snapped the legs in two. It's sometimes impossible to solve poor designs. You have a good chance if you build a cage for this one.

I'm actually not very advanced in this, I've been following 3D printing for a while but actually only started doing it myself a couple weeks ago. I don't have the model on-hand, but I know it was only a couple inches in length and width, and about 3-4 inches tall. Does the printer affect it? I used the M3D micro.

Your description here means you probably used the Thingiverse model I saw. Your printer is FDM which means the layers of the small diameter portions of the model are the weak points. I'm not familiar with the slicer software for the M3D micro. You should look to see if there are adjustments for the supports to reduce the density. Even with easily removed supports, the youngster will likely break the model.

I actually used a model from MyMiniFactory, but it's quite similar. I edited my post to include the link. And you are probably right about him probably breaking it. Oh well.

I examined the link you've provided and the designer of that model should have a refresher course in design. Perhaps his model would be useful in Blender animation, but not in 3d printing. Even a model printed with an SLS printer would have easily-snapped arms. The mouth appears weak as well. If you want a project to share with your brother that will keep him busy until adulthood, scale up the model and convert it to papercraft with Pepakura. I say this partly in jest, as some people have created amazing paper models with great effort.

Would the one on thingiverse( this one ) be better?

The thingiverse version appears to be even more fragile. It does appear better suited to a designed-in cage type support, however, as it has a more vertical orientation. One could also add a tree or landscaping blocks/rocks under the fragile portions. It would not make them less fragile, but would improve the support problem inherent in this particular creature.

I see. I suppose I could also free 6 hours of my time to scale it up to the maximum my printer will hold and just do that lol.

Some slicer software will allow you to automatically "scale to maximum for the printer".  I have seen this in Repetier-Host with both Cura and Slic3r slicing engines.  It will cut your 6 hours down to about 15 seconds.   As said elsewhere, printing solid, that is 100% infill, may help.

Depends how small your printing, if it's the one i see on thingiverse then it don't see why it would break unless:

it's super small
too many or strong support that's hard to pull off?
Not calibrated for the filament - eg temperature too low or too much fan and the layer's aren't properly bonding.
Too much moisture in the filament making it weak
Needs more infill at the weak spots?  (ex. if the neck is thin then infill other than 50-100 is a good idea if you can control that in your slicer).

i would start with the temps/adjusting settings.  really hard to say without a reference photo.
However, i would try a stronger material for toys such as PETG either way.  from experience they'll just break easily anyway from the abuse kids put them through.  PETG has good layer bonding and easy to print, except it's terrible at bridging.  Supports will most likely need to be cliped off with side cutters but it's not a huge deal.

It was rather small, only a couple of inches wide. The support was also kind of strong and hard to pull off, there were parts where I got it halfway, then the rest stuck and wouldn't come off without considerable force. I used a brand new filament just out of the plastic wrap, and as far as I could tell, the calibration was fine.

To increase the strength of small parts I do:

Increase the nozzle size to layer height ratio. While 2 is the most popular choice (0.4 nozzle for 0.2 layer) the science behind the process really recommends around 4 (0.7 nozzle for 0.2 layer).
Increase the number of outer shells. I made dragons with great wings with 4 shells and no infill.
Typical things: raise temp, reduce speed.

Well, it took 3 hours just to print how i described.

+1 Your first bullet point is the real key here. The rest just ensures a successful print. I might add that increasing the extrusion temperature would go well with lower layer heights. This allows each layer to "weld" together easier. Some slicers like MakerWare reduce the flow of filament specifically for supports, so you shouldn't have to worry about the supports "welding" together as easy. This process ultimately leaves the part much stronger and the supports inherently weaker. Just a perk that the part looks better with lower layer height.


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Ultimaker Layer Resolution vs Nozzle Size
On their website they say the following
0.25 mm nozzle: 150 to 60 micron
0.40 mm nozzle: 200 to 20 micron
0.60 mm nozzle: 400 to 20 micron
0.80 mm nozzle: 600 to 20 micron

That confuses me. Why can I go down to 20 micron with the 0.40, 0.60 and 0.80 nozzle but only down to 60 micron with the much smaller 0.25 nozzle? Is that a typo and should say 6 micron?

Have you found & fixed the problem? If any of the answers helped you to get an answer to your question or come to your own conclusions then please do vote & accept an answer (using the tick button next to it). This helps us reduce the unanswered questions list & stops the question from being bumped once in a while. If you found another answer (than those already posted), please add that answer (& accept after 48 hours) to share your experience with the community. If you have not been able to address the problem please update your question.

You need a certain minimum flow rate to achieve consistent extrusion. Flow rate is the product of print speed, extrusion width (proportional to nozzle size) and print speed. If you use a very small nozzle and very low layer height, you'd need a very high printing speed to achieve a reasonable flow rate. Therefore, it's quite possible this is not a mistake and intentional.
Keep in mind that Ultimaker uses 2.85mm filament. With a 0.3mm extrusion width, 0.02mm layer height and 60mm/s print speed, you would need a feedrate of 0.06mm/s into your extruder. The extruder might not be able to develop enough force on the filament at such a low speed (which, owing to the small nozzle size, requires a relatively large amount of force).
The ultimaker can not print 6 micron layers since the smallest increment the Z-axis can move in is 5 microns. 6 microns is not a multiple of that.

I would say that extruder force is not an issue. However, accuracy is, since 0.06 mm/s means a very limited number of steps: assuming 3:1 gear ratio and (very approximately) 4 mm hobb bolt radius, we are talking of about 2.5°/s on the stepper motor: 1.5 steps per second. Microstepping brings it to 24 steps/s, but microstepping are not always very accurate and the position of the axis may lag easily several microsteps on an extruder, resulting in inconsistent extrusion.

In addition of Tom van der Zanden's answer, when the filament moves too slowly through the heated part of the printhead it is very likeley to clog.
I have had this multiple times on my UM1+, most of the time resulting from a heated printhead with no extrusion (before or after prints). So you need to be sure to have a minimum of filament extrusion happening, wich is most likeley not the case when having 0.25mm * 20 micron instead of 0.60mm * 20micron, for example.
You could of course make the printhead move faster, resulting in a higher extrusion, but that will lower the print quality again.
But let me tell you this: Always look out for high extrusion, removing clogs is a real pain!

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How to properly read dimensions for a 3D printer?
I'm trying to find the correct way to read and understand the dimensions of a 3D printer.  For example, if I read the following dimensions for the Robo 3D R1 Plus as 10x9x8 Inch - I want to know what 10 stands for (does it mean print height?), 9 (depth?), and 8 (width?); etc.  I'm not sure if I'm assuming correctly.
I know this should be simple, but I'm not sure where to reference the proper ordering, respective to each aforementioned dimension.

UPDATE

While looking at Makerbot's Replicator technical specifications, I see them listing their dimensions as follows:
Build Volume
29.5 L X 19.5 W X 16.5 H CM
[11.6 X 7.6 X 6.5 IN]

So, if I'm reading this correctly, can I infer that 11.6 IN is referring to the length/depth, 7.6 IN is referring to the width, and 6.5 IN is referring to the height.  Would this be the universal/standard way of referring to build specifications for all 3D printers?

LWH is a very common order for measurements, but it's not specific to 3D printing at all.

Typically LWH is transferable to XYZ dimensions in machine tools (3D Printers, Mills, Lathes, Lasers, etc). ie Length=X Distance, Width=Y Distance, Z=Height.

The 11.6 value, as L, would be the x direction typically, and therefore the left to right as you are facing the machine.  W would be the front to back "depth" or y dimension.  Your notation of "length/depth" is problematic, I think.

Just a thought, that it mostly matters to distinguish the Height particularly. Length and Width are somewhat symmetrical - you can re-orientate the print by 90 degrees with little consequence; you usually cannot do that vertically, and it makes a huge difference to the structure of a print if you do. If your printer has a moving bed, the non-symmetry of X and Y might make more of a difference (I don't own a moving-bed printer: does that actually make a difference to your X/Y positioning choices?).

Having the dimensions of your 3D printer ordered in Length x Width x Height is a common way, but nobody actually decided it.
I think it has something to do with the 3rd dimension being the "new" dimension for printing things, that's why it's appended at the end.
Additionally, the first axis on a 2D-coordinate system usually is the horizontal one, so writing Length x Width makes sense for me.
If you are unsure you can always test your printer (if you have one) by writing your own G-Code that moves the printhead on a defined axis.

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What type filament should I use to produce stamps?
My wife wants me to use an FFM 3d printer to make custom stamps for her to use on paper (scrap books, letters, etc.). She is convinced, however, that they will be too rigid to make good stamps.  A quick google search showed ones made from PLA and ABS. Logically, though, a TPU or similar would address her concerns.  A good quality stamp needs to hold ink and make good, even contact with the paper. It would probably need to be able to be sanded or smoothed in some way.
I am supposed to receive my printer next week or so and am trying to get some filaments, STL files, and accessories I will need ready in advance so I can rapidly learn how to use it.

So even if you show your wife the results on those pages, she won't believe it?    Well, you can lead a horse to water, etc.,  ... just go ahead and print a few -- these won't take long to produce, and let her try them herself.  There are flexible materials but the reviews I've seen say they're difficult to work with (in the 3Dprinter).

@CarlWitthoft Those examples have quality issues (uneven images and drops of ink on paper) and I don't know if using a different filament would give better results.  I was intending to wait to experiment with TPU because it is harder to print. I might need to order it now before I get the printer, however, if I need it to give her what she wants me to print.  Happy wife happy life.

There also exists flexible PLA filament which is somewhere in between TPU and PLA in hardness. Easier to print, and might be suitable for this.

I see three options...
1. Print with a flexible filament:

Many options: TPU as you pointed out, the flexible PLA that Tom mentioned, and others.  Here's an article with a few options from Matter Hackers
I'd suggest printing the stamp side down so you get a nice flat stamp with no post processing.  For any wide gaps, mind your bridging...use fillets or chamfers so the "roof" of the gap is an upside down V or U shape.

2. Print with any hard filament, but use a rubber mat under the paper.

The idea here is to use a semi-flexible surface under the paper to help get uniform contact pressure between the paper and the hard stamp.  As long as your stamp holds ink, this should work okay.

3. Print your stamp shape, then use it to make a rubber stamp.

Making a model and then copying it with your desired non-printable material is a common manufacturing technique that can be used in many situations.  Use of molds for casting and related processes can really expand your possibilities.  Check out Smooth On.  They have several rubber and flexible compounds that you could use for stamps.

Recently I've experimented with printing some Nylon 618 filament after reading stuff online about it.  I'm using a Craftbot original with the stock hotend, keeping the Nylon dry in a ziploc bag.  It prints really well, just tricky to get it to stick to the bed (I'm still working on that), but otherwise it's great.
Once printed, the main difference from PLA prints is the nylon remains more flexible.  If you bend a thin nylon print, it tends to just spring back to the shape that came off the printer.  That's very different from my PLA prints, which will either stay bent or break apart.
I believe that nylon would be a good material for you to try for stamps, because of this flexibility and shape-preserving quality.  The comments show some other materials to try, but I'm limiting my answer here to my own personal experience.

looks cool...but is 6 times more than ABS! Fortunately i should only need a small amount for each stamp and misprints of something so simple should be minimal (once I get the filament working right).


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Should I use different nozzles for different materials?
I know I should use different nozzles for filaments that use vastly different temperatures but what about filament types that use similar temperatures?
For example, PLA and PLA composites like ColorFabb Woodfill filament.  Should I use a separate nozzle for that?

There is absolutely no reason to use different nozzles, not even if filaments do require different temperatures.
The only exception is when printing abrasive filaments (such as glow-in-the-dark and carbon-fiber) in which case you should use an abrasion-resistant, stainless steel nozzle. This nozzle can also be used to to print "regular" filaments but a regular brass nozzle has slightly more favorable properties if you do not require abrasion resistance.

I feel like the absolute in your statement is wrong. What if you print abs at 250 and then try to print pla at 180. The abs will not get removed from the nozzle and make it easier to clog

You purge the nozzle with PLA at a slightly higher temperature. People switch between printing ABS and PLA all the time, using the same nozzle.

My printer's manual recommends performing a nylon nozzle cleaning when changing filament chemistries. It requires fairly high temperatures to soften the nylon, then as it cools and reheats, the nylon is removed at a lower temperature. This process is repeated until no foreign material remains. This process might be considered excessive, but if one desires absolute certainty, it's a good answer.

@fred_dot_u  and there's even "nozzle-cleaning filament" for sale, tho' I have not tried it to see how well it works.

It depends on the size of the nozzle you are using. If you are using a small nozzle, e.g. 0.2 mm, normally, you should increase the nozzle diameter (filament manufacturers often refer to about 0.5 mm nozzle diameters). Wood/cork, or whatever particle filled filament requires a somewhat larger diameter to prevent clogging.

In addition to Tom's answer, note that there are stainless steel nozzles and hardened steel nozzles. The latter is harder than the prior and should be used for abrasive filaments, like filament filled with metal particles or some sort of abrasive fibres like glass or carbon fibre. Note that the addition of fibres or particles may require you to increase the nozzle diameter as fibres or particles may cause clogging. A last nozzle discussed is the nozzle with an embedded industrial Ruby, a design of Anders Olsson, a research engineer at Uppsala University, more information is found on the Olsson Ruby website.
From the Olsson Ruby website, the following interesting image is shown, comparing the wear resistance of the various nozzle materials up to 0.5 mm (from left to right; brass, stainless steel and hardened steel by printing respectively 0.3 kg, 1.0 kg and 4 kg of carbon fibre filled filament):

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Height of printed part is incorrect
I have a weird problem with my old 3D printer, it is a Prusa/Mendel type.
When I print a 20 mm cube, X and Y are correct, Z is resulting 16 to 17 mm.
I have checked the correctness of the movement on Z using the manual controls and there are no issues.
I played a bit with the layer thickness, I have a 0.4 mm nozzle, setting the layer height to 0.12 mm (normally is on 0.16 mm) but no changes in the result.
I am printing PLA on a cold bed at 180 °C without any other particular defect.
I would appreciate some direction on how to solve such problem.

Is the Z travel consistent across prints?  Z travel must be at the root of the problem as the nozzle wouldn't finish the print if there were a 3mm gap towards the end of the print.

@emackey there are not other defects on the printed part. I am not sure how to verify such consistency while printing. As i said, I verified it with the manual control and in that modality it is correct. Thanks fornyour opinion about excluding the extruder settings.

Hi, Felice! I think what @emackey mean about Z-travel is whether the height difference ratio is consistent. So, if you print a box that is supposed to be 50mm high, and it turns out that it is 40mm, you have a 20% error. If the error is consistent, printing a box that is supposed to be 100mm should give you a 80mm result (also 20% error), etc..

@TormodHaugene, thanks. Unfortunately the result is inconsitent. I printe out a 20 mm and it came out 17, the next one was 40 mm and final result is 30. I am starting to consider a problem on the ramp.

Is this consistent on different Filaments? I once had a bad filament that caused to short prints.

This could be related to missing steps

You should check that the steps per mm for your Z-axis are set correctly. This depends on the pitch of the leadscrews/threaded rods driving the axis and parameters of your steppers (microstepping and raw steps/revolution). This Calculator.
Make sure that your layer height is a multiple of a full step of the Z-stepper. The Z-stepper may be disabled intermittently, and when re-enabled it may "snap" to the nearest full step position. If your layer height requires microstepping, you may notice it getting rounded down or up due to this.
For instance, if a full step were 0.08 mm, then 0.16 mm layers would require 2 full steps, printing fine. 0.12 mm layers would require 1 full step and a half microstep. Due to rounding, some layers might be reduced to 0.08 mm instead. This might account for the height discrepancy you're seeing (though 0.08 mm is quite a high, unrealistic amount for a full-step).

Thanks for your nswer. As you said the steps calculation are the result of the mechanical components, so there is no reason to adjust it to compensate a problem coming from somewhere elese. I also tried with 0,16 and 0,2 mm extrusion but the problem is still the same. I am considering the problem coming from the ramp i will try to play a bit with the ramp current. Thanks for your answer, i will check carefully your hints and share the results.

You could check that the stepper driver IC for the z direction is not getting too hot while printing. If this is the case it may be that the current adjustment of the stepper driver is set incorrect causing it to skip steps. however you would expect the same behaviour in manual operation.

Thanks to your advices I pointed my effort on the root of the possible cause on the Z axis.
I swapped the Polou driver between x and z and clearly noted that now the problem is on x. I had to conclude that the problem is with the Polou driver which randomly looses steps.
What is surprising me is that on the Z axis I have two motor type Nema 14 which should work at 0,75A therefore 1,5 A total. The Polou driver, old type, is rated at 1A. So it is not a surprise, now that I have learned about this configuration, that the z driver is giving troubles. The problem was there since the beginning and with the ageing of the components it revealed itself.
I will replace the actual Polou drivers with the new type rated at 2 A and restart from there.
Thanks for the advices.

Maybe adjusting the current (via the potentiometer) to be lower/higher will fix the problem without replacing the stepper drivers.

@TomvanderZanden, thanks but I tried. The driver is faulty because gives the same problem also on x where i have only one motor. I even tried to adjust the current but no success. I am replacing it.

A suitable test part for this problem, to check if the bad scaling is linear or the result of missing steps (as was identified in this case) would be a ramp, or sequence of steps. You can check the linearity using a straight edge, and would be able to perform repeated tests to identify of there was a specific Z location where steps were more likely to be lost (for example due to some tightness in the motion system).

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Hictop prusa I3 clone - broken z axis right bracket bearing
I was very excited to get my 3d printer but sadly I didn't realise I'd installed the z axis upside down. There's a plastic coupler that goes into the hole for the polished rods it broke then released 1 -2mm sized ball bearing all over my floor.
Is it possible to just replace that coupler thingy?
Or if I 3d print a replacement will it still need that coupler thingy?

The first picture is the one that spilled it's guts all over my kitchen floor.
The last image is an example of how it used to look like but on the left hand side. I know the image looks like it's the right but you can see a bit of the horizontal rods if look closely

Can you provide a picture of this part?  I imagine it's a linear bearing but a plastic one with ball bearings in it is not something I have seen.  Either way, you need a picture or better description of what it is and where exactly it fits.

That "plastic coupler thingy" is actually a linear bearing, and it consists of a metal shell, and the metal balls roll between the smooth rod and this shell. The plastic part has a channel that guides the balls in a circle.
It would be best to replace the entire bearing (metal part+balls+plastic liner). It's probably either an LM8UU (most likely) or LM8LUU bearing.
3D Printing a new part will not give good results.


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Is it possible to make a hermetic sealed 3D Printed case?
I am wondering if making an hermetic box is feasible using 3D printer. The box would be a cube with a front face removable, with screw and sealing joint to close it.
I searched for different materials, however, none talks about hermiticity. (However, I found a product that seems to improve water resistance of 3D printed items here, which might be a starting point)
Does anyone have experienced to make hermetic things ? I am specially interested in carbon fiber reinforced materials.

What sort of printer do you have that can use carbon fiber?

@CarlWitthoft Carbon-fiber filled filament are somewhat common. It's not pure carbon fiber, though. Same deal as the "metal" and "wood" filaments.

I' go on a professionnal company for doing that, but as Tom said, it seems that more and more carbon reinforced-filaments become available, and compatible with more hobbyist printers.

Over extrude. It will look a mess but it will squeeze its way into all holes, then sand it down.

A few thoughts that might help...
Material:

ABS can be vapor smoothed with Acetone which results in the layers sort of "melting" together to form a smoother, and less porous surface.
Other plastics can be smoothed with compatible solvents, but I've not tried solvent smoothing with anything other than ABS.  Be careful if you try.

Print Method:

Consider slightly higher print temps to increase layer adhesion.  You'll likely have to compensate with extra retraction to avoid excessive stringing.
Consider more perimeter layers and more top/bottom layers.
The CF materials are stiffened with chopped CF strands...I think it's a stretch to call them "reinforced" unless you happen to have a Markforged printer or similar.

Sealants: This is probably your best bet.

Epoxy: Generally considered effective for producing hermetically sealed containers.  Dip or brush on.  Mind your VOC's and pay attention to working time.
Plasti-dip or similar sealants: These may be good enough for your application and result in a rubbery coating over your part.  Good for water sealing, and may be close enough to hermetically sealed for your needs.

Design:

To mechanically seal the opening, there are many options depending on your requirements.  O-rings, gaskets, etc.  If you use a rubberized dip, you may be able to skip the gasket.  You could install a few threaded inserts around the perimeter of the opening, put in the screws, then dip.  After drying, you slice around the screw and remove it (this just keeps the coating out of your threads)  Dip the cover as well.  Then when you screw on the cover, it will provide a water-tight seal.  To help make a good seal, apply a silicone grease to the mating surface.

I hope this helps.  :-)

I have very little experience printing waterproof stuff.
I printed a flower pot in ABS some time ago. Right after print it was leaking water. Then I processed the pot with acetone vapour to create a layer of melted ABS on the surface of the pot and then it became water-proof.
As another option for non-solvable in acetone materials like PLA I would rub in some sealant paste to the surface, but I never have actually tried that.
Another thing to consider: you should think carefully about your design and may be even conduct few experiments to verify printed part meets your mechanical criteria. Unlike injection molding, FDM prints are breaking more easily in some directions.

Thanks for the advices. The water leaks shows that it's probably porous. I wonder if the process and the paste are reliable. Have you been  using your pot since ?

I never tried paste. Only acetone. Pot was water-tight until the end of life.

I'm currently working on a project where a kind of box has to stay underwater, and until now, the best hermetic system I found is using coatings.
The best of them until now is PVC glue that I use on ABS as a coating with a little trowel. What I find nice is that's quick and that looks smoother and resistant. A disadvantage is that you need some practice to make something quite esthetic...
An other option I've tried is a very fluid mastic call "Creeping crack cure" which is perfect for 3D print since the part literally drinks it. Then, when it's dry, it also acts like a glue and can reinforce the part. A disadvantage I have however is that the mastic becomes no more transparent when the part stays in water.
Still not the perfect solution, but at least, no water goes through my parts :)

I believe this can be achieved using o-rings.  That's what they use for scuba diving lights.  The component doesn't need to be circular, but the o-ring needs to be slightly smaller than the component so that it is held in place via tension.  Additionally, you'll want to create a groove for the o-ring to set it in and make sure that the o-ring protrudes slightly so that it applies pressure and creates a tiny amount of friction when it's coupled with its counterpart.  Apply some type of lubricant to prevent the o-ring from sliding out of place and to keep it from drying out and cracking.

Ok, thanks for your answer. I am also wondering about the printed material itself, is it dense / hermetic itself ?  While printing, I imagine plastic melting, could it include air bubbles in plastic making it somehow porous ?

There are rectangular gaskets (aka "square o-rings") so if the box in question has a standard size gland, those can be used as well as a circular o-ring.


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Laybrick - Gaps on top layer
I'm trying to print with Laybrick and for the most part it is going.  The problem lies with the top layer and gaps appearing.  I've tried increasing the number of top layers but the gaps still appear.  Any ideas what else I can try?
I'm using Simplify3d.

Did you try raising the temperature? I would have done that second after increasing number of top layers.

Raising the temperature leads to a different texture which I don't want.

The solution was a combination of several items.  The primary one was slowing down the top layer of the print significantly.  I was using 3200 mm/min for the print and used the option 'solid fill underspeed' to slow down the top layers to 40%.  I increased the top layers to 7.  I also increased the infill, to ensure there was support in the tiny top pieces.  I also decreased the minimum infill length to 0 to ensure the infill went in tiny places.  Finally, I used the 'Concentric' external fill pattern.
At some rotations of the model, I had slight gaps in the corners of the model, increasing the number of outline layers fixed it.
I also decreased the temp to 160 compared to the initial print above.

When using Simplify3D, you may try referring to their awesome troubleshooting guide: https://www.simplify3d.com/support/print-quality-troubleshooting/#holes-and-gaps-in-the-top-layers
3 reasons (from the guide) for gaps in the top layers:

under-extrusion: you may try to increase extrusion multiplier to see if this helps
low infill percentage: not likely in your case if increasing number of top layers did not help
not enough top layers: you already tried increasing number of top layers.

In addition to that, you may change certain parameters (such as extrusion multiplier) for a given number of layers by using Simplify3D features. It can be helpful to avoid problems to for the rest of the model.

Are you sure you can change extrusion for only certain layers?

It did help (I'm already aware of that site) but cost to much to implement for the pieces

You can create more than one "process" for a certain model and assign them for different ranges of layers.

I don't believe you can assign different layers, just z height. Plus I have heard there are a lot of issues doing that

This may perhaps depend on the version, but what I've seen is a layer range in 'Advanced' tab. Going back to your original question, I would rather start with increasing flow rate (or checking actual nozzle diameter).


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3D printing related safety precautions for a baby rattle
I've a friend who is expecting.  There are several adorable weapon themed rattles on thingiverse.  I am, however, concerned about safety associated with such a product in the hands of a baby who will gnaw on it.  To me the safety concerns here are much larger than for most food handling applications.
What steps should be taken to ensure such a print is safe for use?
This includes: filament selection, pea material selection, wall thickness, smoothing, construction, etc.
My current thoughts are as follows: "food grade PLA", dried peas, sanding, and single piece construction

You're on the right track.  Since you asked for "steps" here you go:
Step 1. Choose a safe material:
Consider chemical safety and physical safety. Food grade PLA should be chemically safe, but could be too brittle depending on the design you choose.  PETG, T-Glase, or similar filaments (depending on dye) are normally also chemically safe and are less brittle than PLA so may be a better alternative.  ABS is NOT typically considered safe for food contact.
Step 2. Choose a safe design:
If using PLA, be sure the design is robust enough to ensure it won't break.  Broken rattles with sharp edges make baby...sad.  Even less brittle filaments can still break with jagged edges if the design is fragile.
Step 2a. Choose a single piece design:
Choose a design that requires you to add the peas (or other safe filler) during the print such that the finished rattle is fully enclosed.  This will minimize parts becoming loose or peas spilling and minimize choke hazards.
Step 3. Consider post processing to improve safety:
Sanding could reduce ridges and minimize crevices that could harbor bacteria, but sealing it with a food-safe sealant may be more effective.  There are many sealants that the FDA considers safe, but polyurethane or food-safe epoxy finishes will work well with PLA. (If you use a different material, test to verify good adhesion.)
Step 4. Test:
Make a test rattle and run it through the paces.  I guess you could chew on it, but since babies don't have teeth, this might invalidate your data...
Step 5. Consider alternatives such as professional printing services:
If your tests don't inspire confidence, professional services can offer additional materials (metals, ceramics, etc.) that could be safer than a typical fused filament printer.

+1 for the food safe sealant comment.  If it has dried peas (or other perishables) inside of it, I would be worried about bacteria getting inside the object and festering.

Welcome to the site. Nice answer!

Several ideas I didn't have. Good. Are dried peas good or is there something safer?

Good point, BrainSlugs.  Thanks, Tom.  Kaine, you may consider something  more stable than dried peas or the like...maybe clip off little bits of the same filament you print with or even print little beads or pellets for filler.  That might be a waste of time if you were manufacturing these, but for a single item it's probably not too much more time.  That would eliminate any chance of chemical interaction between the beads and shell...probably not a concern anyway, but it would eliminate one more potential risk.

Having loose plastic inside scares me incase it somehow breaks. Dried peas or raw beans are digestible...if barely. I will print a single large pea of the same material.  This pea will be too large to be a choking hazard.

Also consider the nozzle on your printer. Most nozzles are made of brass, which is not considered food safe due to the presence of small amounts of lead. Stainless steel nozzles are available which will not perform quite as well as brass but are food safe.


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3d Key not strong enough
I 3d-printed a key.

When I put it in the lock the pins move but, when I go to turn it the key rips and the lock doesn't turn. I compared it to the real key and it's identical. Is there something I can do to make it work and not rip? Is there some filament that I can print it out of? I used ABS.

There's a reason nobody sells plastic keys to go in metal locks... it's just not a good combo. perhaps a more exotic filament can provide more rigidity, but I'm certainly not knowledgeable enough of this to tell you. I'd start by taking a look at the material specs for some of taulmans offerings, if they're available.

With you printed key in slip a small flat blade screw driver or a small knife blade in along side the key and see if you can turn the locking mechanism.  This will let you know the key actually does move the pins properly.  Are you polishing your finished print with acetone after your done.  This will tighten up the fibers a slight bit.

I must admit, I've never printed a key...but I think I can help anyway:
Print method:
Consider printing on side, solid concentric infill.  Or, if you can't manipulate your infill pattern, just increase the perimeter so you get the same effect, several continuous perimeter layers around the outline of the key.
Print material:

Elongation before break is important here in addition to tensile strength...you need it to be stiff enough, but not brittle.
ABS, PLA, or HIPS: Not likely to be successful...but maybe.
PETG and PETG based filaments like T-Glase, N-Vent, nGen, INOVA-1800: A little better, but still likely to deform and/or break.

Polycarbonate: Great for this, but is a fairly advanced material which tends to require pre-drying, enclosures, and PVA for hold down as well as a hot end that can handle at least 290C.
Nylons: Good, but most Nylons may be more "bendy" than you want for this.
Taulman's Alloy 910: Bingo. This should work nicely if you'd rather not struggle with printing polycarbonate.  Alloy 910 prints near ABS settings, sticks well on a PVA-treated heated bed.  (I use 85C for bed)
I would not suggest a CF filled filament for this because they tend to be brittle.  Matter Hacker's NylonX with CF is a possible exception since it's nylon based, but I haven't tested it...yet.

CF Nylon is the stiffest material out there and certainly stronger and more impact resistant than polycarbonate. A key doesn't need to be flexible nor impact resistant, CF Nylon would be my first choice. PLA would be my 2nd choice as its stronger than Nylon and ABS.

That is correct! Take your raw ABS plastic and try to bend and break it. Do it again with a few lengths. Pretty easy to break it right?
You issue is the material is not up to par with your goal. Your heavy duty lock takes too much force to turn.
Your solutions are to

Find a stronger material. These are considered stronger than PLA / ABS

PVA
PET
Polycarbonate
PETT (SHATTERS!)
POM, Acetal

Use the PLA to make a lossless cast of the key and use metal
Find a easier lock and or invest in oil for the lock.

Which direction are the layers being printed? If the layers are printing top to bottom (in relation to your picture) there isn't a lot of sheer force required to break the key when turning. If you make the layers print from left to right you might have better luck.

I don't think it was printed like that. If it were printed like that there would be a lot of overhangs, which wouldn't have come out as well as we see in the picture. In the second picture, it doesn't look like it snapped between two layers, but instead the entire thing deformed.

I agree that layers, shells and infill needs set to optimize the print.  Plastic keys do work (at least one time).  AAA has provided it clients with a spare key cut into a credit card for backup use in case main keys are lost or locked inside.  And there is the soda bottle key which in hard to turn locks the addition of a "tension wrench" is needed.

"You're going to need a bigger boat^H^H^H^H filament" .  Perhaps one of the carbon-fiber-loaded filaments will hold up, or perhaps a bunch of silicone spray dumped into the lock cylinder is needed.
If you want to get really fancy, start with a thin metal key blank and deposit the filament around that. This might give you enough structural strength.  I don't know exactly how you'd print on three sides, as typical RepRaps and their ilk aren't set up to work around an object. Possibly printing with the key vertical and zero infil would allow you to insert a metal stiffener after printing.

What is the purpose of the comment about boats? Your comment about deposition the filament around a metal blank is not achievable with any standard printer so I'm not sure how that helps.

@TomvanderZanden  You dang youngsters!  See "Jaws," a 1975 movie.

@TomvanderZanden I think the "^H" is supposed to mean he's pressing "backspace", like the end result is "You're going to need a bigger filament". -- I've seen weird hacks where you can print a hollow area (without infill) to insert a captive nut on reprap printers, it's definitely not trivial though.  (Which is lame because that needs to be more of a thing!) -- I bet with some work, someone could use a similar approach with a key blank.

First step is to optimize the print, layers, shells and infill.  While ABS should hold up, if optimized, for at least one use.  It may not be the best filament.  PLA actually tests higher PLA vs ABS.
As I had posted in a comment, finishing ABS adds strength to the filament bundle. An acetone dip, vapor or hand wash of the part helps bond the outside edges.  Parts that I make out of ABS for use on my car and motorcycle I vapor finish then polish with a soaked rag for a much more durable part.
Comparison tests of filaments are out there for the searching SUCH AS THIS ONE which compares strength of common filaments in use as a caribiner.  But finding one that does a true comparison like the ABS vs PLA that I linked I have not seen.
If you do look at other filaments I would avoid ones like iron, stainless, brass, carbon fiber, etc. as these actually are shown to be reduced in strength as the particles suspended lower the filament bonding.

I misread "while".

You can print this 100% solid and will still likely fail in my option. Only solution is stronger plastics.

It is possible in some cases. KEY PRINTING


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Take a detailed model and make it suitable for 3D printing?
I have a model I would like to print, specifically it is a free-for-personal-use model of a car, complete with interior.
I would like to print it, but it is unprintable. I have tried to fix it in netfabb, which works OK. But now I realised I have another problem - the inside of the car is hollow, and has a full interior. I just want the shell of the car and a solid block (complete with opaque 'windows').
How would I take a detailed model and somehow extract a solid 3D printable model from it?

This is by no means an easy task, and requires decent CAD modelling skills. As an answer to this question would need to be basically an entire CAD tutorial, I've voted to close this as "too broad". You might be able to limit the scope of this question by considering just one 3d modelling package (as right now an answer could address one of a 100 modelling tools), but even then it is too broad in my opinion.

You're going to use a lot of unprintable words while dealing with this unprintable shape :-).   If you have a model w/ enough sub-elements, then just delete all the elements not visible from the outside.  At that point you might be able to slice and specify infill; most likely you'll need a bunch of support posts specified if you want a detailed undercarriage.

"unprintable words"  Nice.  :-)

James, what is your starting file format.  Is it an STL or other?  Maybe that will help narrow down your question and you can get a specific answer that will help.  Also, if the file is online, maybe you could add a link?

I would recommend "The Maker's Muse" youtube video channel.
In particular this video Fixing impossible STL's with Meshmixer 3.1.118 BETA might solve your problem.
Few other videos which might help:

How to make Engineering Assemblies 3D Printable using Meshmixer
Add smoothness to your meshes using remeshing! 3D 101
A Detailed look at Processes and Profiles in Simplify3D
Tidy up your prints with the Modifi3D
How to Print Bigger Things - 3D Printing 101


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Can I print jewelry without any loss of the precious metal?
What is the 3D printing technology that allow to have minimal loss in precious metals when 3D printing jewels?

The jewelry industry typically uses printers that print in wax, and transform the models into precious metal by lost wax casting. Statasys offers wax printing in their Solidscape line, 3D systems offers ProJet. With this process there is basically no waste, since you can remelt the casting sprues.
I am not aware of printers that print directly in precious metal. It might technically be possible with DMLS but you have to fill up the entire machine with metal powder, which is cost prohibitive (and potentially more wasteful).


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Connector Suggestion for Extruder and Heatbed
On my Reprap-like 3D printer, I routed all the wires to a spot near the base; for the motors, endstops, thermistors, etc, I plugged them all into a DB25 breakout board, and that's working great.
For my Extruder (12v), and my heat bed (16v), I'm using a 4-pin molex connector -- like we used to use for old hard drives and such, and it's working, but it gets a bit hot, and my print bed is having trouble reaching temperatures that it didn't have trouble with before. -- None of the wiring gets hot at any other point, and none of the other connectors get hot. -- The only thing that gets hot is this one molex connector.
I believe the heat is caused by passing too much current through that molex connector. -- I'm curious to know what other connectors might be better suited to this task.  Can you recommend something that's worked well for you, or others?
I prefer not to double or triple up this connector if it can be avoided, so that I can just have one physical connector to disconnect there, and so that I don't end up mixing them up. -- also, being able to easily disconnect it is important (it's hard to work on the reprap if I can't spin it around or turn it over, etc., that's why I'm using connectors for everything).

You might be able to use one of the connectors (Deans Ultra, EC3, XT-60/30, Bullet) that are normally used for RC models. They're made for very high currents. The XT60 connectors depicted below are rated for 60A continuous (well above what you'd need for any heated bed); their smaller XT30 cousins are good for 30A but less commonly available.

(Photo by Mark Fickett)
For your extruder you wouldn't need anything quite as drastic as an XT60, even a simple JST connector would suffice (though if you are going to source XT60/30's for your heated bed anyway, you might use them here as well).

(Wikimedia Commons, Mike Mahoney)

Thanks @Tom, I'm looking at these on Amazon right now, and I'm trying to figure out, are these solderable, or do they crimp, or what? -- What's the preferred way to attach wires to these connectors?  Do I need a special crimping tool, or can I just solder them?

These are meant to be soldered. They have a semicircular tube on the end, which you fill up with solder. You should also pretin the wires. You then melt the solder that is in the tube, and insert the wire. See e.g. this

+1 RC battery connectors are a great option.  Easy to source, cheap, and easily handle the current.  Another option is Anderson Powerpoles. They crimp instead of solder, they can be made into multiple wire bundles, and they have a single style connector that fits together (no male/female).  Like these: link  I like and use both.

I agree with Tom's answer about RC connectors. Another good connector option worth considering is Anderson Powerpoles.

They're "modular" so you can use them to assemble connectors with multiple wires.
They crimp instead of solder (I really recommend the special crimping tool if you plan to use these regularly)
They're more expensive
No male/female, you use the same connector on both ends so you never run out of either male or female ends.
The small size is a little larger than an XT60 connector.

Both good options depending on your specific needs.

Neat. -- I may look into these for a future project, or if the XT30 connectors end up not working out. -- How much current can they handle?

The size shown here works with 15, 30, or 45 amp spades.  The special metal spades get crimped onto the proper gauge wire, then they snap into the plastic housing.  They also have larger sizes and all sorts of accessories like panel mounts, etc.  More here.

I've had great luck with "G16 aviation connectors" -- easy to find with a Web search, and they come in any number of pins from 2-10 (the 10s are a little harder to find). Round (so easy to panel-mount), metal barrels, locking ring so they don't come loose. If you get ones with a couple extra pins, you can double up on pins without having to double up on actual connectors. I used a 4-pin for the hot bed (2 power, 2 thermistor); 10-pin for the extruders (4 motor, 2 heater, 2 thermistor, 2 fan), and 8-pin for each axis (4 motor, 4 limit).


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Keeping my filament spools from getting knotted?
This is something I've ignored for awhile, but it keeps cropping up, and occasionally, if the filament snags real good, it can mess up a great print half way through, etc.
Basically I have my filament spools hanging on a PVC pipe mounted directly above the printer, and the printer just sucks it in from the spool, but occasionally it becomes knotted at the spool, or becomes otherwise tangled.
I'm thinking even if I completely unwrapped and rewrapped all of my spools so there was no trace of a tangle, what's to stop it from happening again? -- What's a good strategy for managing this kind of issue?
Edit: From some of the answers below, it seems that maybe the travel of my X carriage back and forth could be why my spools keep getting tangled. -- It looks like many people have their spools at about 90 degrees from mine (rotated relative to the Z axis of the printer), so that the travel of the X carriage won't have that affect. -- Also guides, etc are probably a good idea.
Here's my current setup for reference (filament removed):

I had the same problem with my FFC dual.
Consider using some kind of retaing clip to hold the spool in place, so it doesn't move back and forth on the post. This spool holder worked for me:

Another thing that can help is to make sure you are pulling the filament from the middle of the spool.  This worked for me:

Interesting.  Also the orientation of your spools -- like on the Z axis -- is 90 degrees offset from mine -- I was just thinking that that probably makes a big difference too -- as my X train moves horizontally, it's probably what's causing the filament to become overlapped!!

When I first set up my printer, the spool was able to spin freely. Filament was making loose coils on the outer layer of the spool. Snags happened frequently. I decided that not allowing the spool to spin faster than the rate draw of the filament might improve the way the filament was feeding.
I put more physical distance between the spool and the machine. The filament stopped bunching up in loose coils on the surface of the spool, and the snags went away. The increased amount of slack between the machine and the spool seemed to absorb the "overshoot" of the filament draw and the spools became much better behaved. I also was able to run the spool down to the end more consistently than before.
Not everyone has extra room to use, and not all extruders are conveniently oriented, so moving the spool further away from the machine won't work for everyone. I believe a guide or some sort of dampener would serve the same function, if the underlying problem is the spool loosening up enough to where loops of filament get caught under others and then snag. What worked for me was to stop the spool from "racing ahead" of the rate of draw and loosening up enough to snag.

Always keep track of the loose end of the filament. It's either in your extruder, or fixed to the spool (either with a clip or clothespin or just by threading it through the holes which are usually in the rim of the spool, provided for just this purpose). The only way a spool can get tangled is if you let go of the loose end of filament.
Though not technically tangled your filament can also get stuck if the spool does not properly unwind (and the filament gets wrapped around the axle that supports your spool). Make sure your spool can rotate on its holder easily (ball bearings are not needed, a simple round axle is enough). Make sure that your printer pulls on the middle of the spool, and not sideways. If necessary, could build a guide (such as a small ring or tube for the filament to pass through) to keep it centered.

Right, I put the filament through that hole and tie it off when I'm not using it. The problem is during printing is when it becomes tangled. – Especially with a new roll of filament -- because it will always want to come off the spool sideways when printing, and that can create really bad tangles.

That's not technically "tangled" - at least, it's not the kind of tangle you can fix by rewrapping spools. I edited my answer.

Yeah, my spools can rotate freely, but I think I will need a guide, and also I'm going to consider remounting them at a 90 degree angle on the Z axis -- (I'll edit the post to include a picture). -- Is there... like an equivalent of a one way "valve" for filament? -- maybe something that ratchets? -- Like something that, will let me pull the filament off the spool, but if it becomes slack, will not let that slack translate back up to the spool?

I used this solution, it makes a lot of sense, because I store the filament back in a box and the tip endup getting knotted.


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Z offset incorrect
Repetier host 1.6.2.
Used Slic3r and CuraEngine in RH1.6.2 to slice my prints.
OK, I have a problem. Z offset does not work. Well...

Flashed EEPROM clear.
Enabled EEPROM and CHIT CHAT within the firmware.
I've set -0.4 in Marlin firmware 1.0.2-1 stable and flashed it.

results in
    G28; home axis = works
    G29; auto level = works
    G28; it goes to home and then sets Z to 0.4
    G1 Z0; brings nozzle down from 0.4 to 0, so this works also.

But when I slice with Repetier host 1.6.2 with the latest slicer/curaengine, it does not go down 0.4 mm before starting to print.
I've set the first layer to 0.2 mm, but when it starts printing the first layer, it goes from 0.4 mm (after home Z is on 0.4 mm) to 0.6 mm instead of 0.2 mm! ...
How do I fix this?
Gcode start:
    ;Generated with Cura_SteamEngine 15.01
    ; Default start code
    G28 ; Home extruder
    G29 ; Auto level
    G1 Z15 F100
    M107 ; Turn off fan
    G90 ; Absolute positioning
    M82 ; Extruder in absolute mode
    M190 S35
    ; Activate all used extruder
    M104 T0 S230
    G92 E0 ; Reset extruder position
    ; Wait for all used extruders to reach temperature
    M109 T0 S230
    ;Layer count: 226

It's definitely Repetier or its slicers. I'm using Cura 15.04.6 and it also calculates the offset set in Marlin when printing! I'm trying to use Cura 2.1 because it's newer, but I do not get the print USB option in Cura 2.1 :/
I just don't get it, it was printing very nice the first 4 layers, and suddenly it moved up more than 0.5 mm and continued printing there, in the air.
Yesterday's print:

Today's print:

Your question is a little hard to pin down, but I'll try to help anyway.  :-)
Z-Offset:

It appears you may be misunderstanding the way z-offset is supposed to work especially when it comes to Marlin setup and routine bed leveling and printing.
This may help.
And this

Print Quality and Skipped layer issues:
From your pictures, you do have some loose or wobbly belts, pulleys, rails, or other mechanical components causing excessive play in your x and y axis...very apparent with the way your layers don't align well resulting in the very visible lines.  You can address this in two ways:

Make sure your physical components are tight and rigid enough to handle the print speed you're using.
Slow down your print speed to something that your machine can handle with reasonable quality...whatever reasonable is for you.

You mentioned skipped layers.  I see that in your tower.  This is most likely caused by:

Tower legs too thin so Cura skips it because it can't fit there. I'd suggest using the layer preview in Cura, if the layer doesn't show in the preview, it won't print.  If this is because the leg is too thin for your nozzle diameter, you could increase the scale of the tower, edit the model to have thicker legs, or install a finer nozzle.
Issues with your mesh so Cura skips it.  Also use Cura's x-ray view.  If there are red areas, you have issues with your mesh.  Search for ways to fix your mesh and make sure your model is good to print.

However, it could also be caused by issues with your filament feeding or your hot end.  Clogs, snags, etc.  If this were the case, your previews in Cura would all be fine.  To solve this you could:

Increase your print temperature slightly to ensure you're filament is melting quickly enough to support your print speed.
Slow down to allow the filament plenty of time to melt.
Make sure your feed system is snag-free.
Make sure your feed system is clean and adequately gripping the filament so it can push the filament into your hot end reliably.

I hope this helps.  :-)

Also looks like it went a bit fast on the upper part of the Eiffel Tower, increasing minimum layer time might help a bit.

Hi! Thanks for helping me out. I have had few good prints, but then it randomly starts printing bad. When I enter the Z offset in the Marlin code to -0.5, it doesn't go down 0.5mm when starting the first layer. It stays at the same height, which is 0.5mm above the bed. So Z offset doesn't work trough the Marlin code. Then I tried Z offset in Repetier and the same happens. Does not lower. When setting Z offset to 0 in Marlin, and then adding G92 Z0.5 in the GCODE, it lowers the model in the slicer, so 0.5mm of the part goes into the ground. But adding that to the Gcode, lowers my nozzle to.....

... the right height, which is one paper height between the bed and nozzle. The prints turn out better this way. I have figured out some lose parts which I will tighten up soon and test it out again. The legs of the eiffel tower do show normally in the slicer. I managed to print again with my printer, but now with really small layer shifts (which is because of lose parts I guess), and some missing outer layers (like it did not feed enough filament at that moment.). Increasing filament feed rate from 100 to 130 and increasing the temp from 220 to 230 fixed this problem a little bit, but...

Still missing outer layers every few mm heights. maybe this is also caused by little movements in the components? Going above 230, e.g. 235, the filament feeds really hard. I thing it's too hot for the plastic housing inside the extruder hot end, or the filament just gets burnt or something. ... So my question, why does Z offset not work when adding in Marlin code, or slicer? I will update here if the quality improves after making everything stable. Thanks again

"randomly starts printing bad"...yeah, I know it can seem that way sometimes.  There are many many variables that sometimes play together in mysterious ways.

Based on your comments about Marlin Z offset, I think you are misunderstanding how that is supposed to work.  I'll update the answer to include some helpful references.

Thank you for your help! I am printing some idler pulley for my x and y axis bearings (608z) so that the belt doesn't slip to one side. It moves really hard I noticed when the belt is sticking to the sides. Then I found out that my y axis just wiggles, so need to tighten that up after this print.

Also, your answer will most likely solve lots of my problems and has answered my main question. Thank you :)

Glad to be helpful.  Good luck!  :-)


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Makerbot Replicator 2 restarts after preheating the hbp
I've recently upgraded my Replicator 2 with a heatbed and the more powerful power brick (9.2A). The problem I'm having right now is that the Replicator restarts right after the preheat of the bedplate finishes. It does not matter which temperature I set as threshold - it restarts either way.
So it restarts even in very low temperatures on the HBP. Tried upgrading the firmware and even switch firmware to Sailfish, but it's still the same issue. I would really love if someone could help me with this.
Edit: I've checked my cables and it seems okay. Themistor is connected via pin 1 and 3 and the power should be fine.
Edit2: Found the problem. It was a faulty hotend that caused all of this. It works to print with , but togheter with the heated bed it makes the Replicator to restart.

Did you ask this same question earlier, delete it, and ask it again just to do an edit? You could just have used the "edit"-button.

I saw that I had added the question to the "meta"-sub forum, so I moved it. Sorry about that.

More info about your hardware changes would probably help a lot.  Based on what you've said so far, I'd guess you're experiencing hardware issues...probably a brownout.  What are specs of power brick and heated bed?  How did you connect everything?  We'll figure it out, just need to dig a little deeper.

Clues so far:

You changed your hardware to add a heated bed.
You've had the same symptoms with three different firmware versions.
Your Replicator 2 reboots right after preheat, regardless of temp set.

My Assumptions

You have not tweaked firmware or other settings that could cause both the heated bed and hot end to draw high loads simultaneously.  (By default Makerbot handles this in firmware, avoiding situations that could over-tax the 9.2A power supply which isn't really enough to handle preheating both at the same time.)

Potential Problems: Listed starting with the easiest to fix...

No problem, carry on: If you are printing from the USB cable, a restart after preheat could be a normal condition.  The Replicator 2 reboots to reset inputs when you start a print over USB...this is normal.  So, if you're preheating with the buttons and then you start a print, this would be expected behavior.  Try printing from SD card and it shouldn't reboot.
Power Supply voltage switch: Make sure your power supply voltage input switch is on the correct voltage, either 110 or 220.  Having it set to 220 when you're using 110 can cause reboots due to insufficient power. (brown-out)
Wrong heated bed: If your heated bed draws too much power (it is higher power than the Replicator 2 can support with that power supply), you may get reboots due to insufficient power. (brown-out)
Short somewhere: A short somewhere in your system could cause too much power draw.  This could be somewhere in your heated bed, your hot end, or other.  Inspect carefully around the areas where you moved wires.  You could have a frayed wire contacting the frame, a screw shorting between two wires, or a little stray "hair" of copper wire sticking somewhere it shouldn't.  This too will cause a reboot due to insufficient power. (brown-out)

I hope this helps.  For further reference, read this thread as I believe it has some relevant info.  :-)

Thanks for you answer. Will take some pictures tonight togheter with more information and post so you can see how it looks.

Hi. Here's the pictures https://www.flickr.com/photos/145776060@N02/albums/72157675011775866 Hope you can see something errorish :)

From what I can see in the pictures, it looks like your wires are connected correctly.  I'll update the answer with a few things to try and a good reference for further troubleshooting.  :-)

Thanks for this great info @Chris. I've removed the hbp and have now re-drawn the cables without success. Disassembled the bed and it's a Makerbot 24v 130w plate, so should be enough power to run it. I'm getting really annoyed about this :/

You did not solve my issue, but marked your answer as the correct one either way since you gave such a good answer :)

Found my problem. Apparently the hotend is misbehaving (When I pulled the cable it works). So have ordered a new one. Thanks for all your help!

Yahooo!  Glad you solved it!...and bravo for not giving up.  Well done, sir.  :-)


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stable FDM materials
What materials, available as filaments for use in FDM printing, are known to be the most physically and chemically inert? In particular, stability (not necessarily simultaneously) in the presence of the following should be assumed:

pH 0-14
oxidizing agents (ozone, permanganates, dichromates, acidic hydrogen
peroxide)
organic solvents (particularly acetone, methanol, toluene, formamide)
temperature up to 160 degrees Celsius
pressures between ~10^-7 torr and ~2 bar
oxygen or argon plasma

Tough set of requirements and definately pushing into the professional domain.  I would recommend checking out ULTEM 1010 Resin which is similar to PEEK but has a higher glass transition temp of 215 °C.  Check out the spec sheet from Stratsys.
I hope this helps.  :-)

Thanks for bringing polyetherimide to my attention! I will study its properties further.

PEEK, a plastic known for its superior chemical and physical resilience (http://www.zeusinc.com/materials/peek/chemical-resistance-chart-peek), has been successfully used for filament-based printing (https://3dprint.com/52713/indmatec-peek-fdm-printing-filament/). However, it is unlikely to be an option on most existing printers given its high melting temperature (around 343 degrees Celsius, https://en.wikipedia.org/wiki/PEEK). Though it does not meet all the criteria proposed (for instance, its glass transition temperature is around 143 degrees Celsius), overall it is a fairly good choice.
Teflon, an obvious choice, unfortunately has a decomposition temperature very close to its melting temperature, and appears to be unsuitable for extrusion.

Also worth noting that Teflon produces somewhat nasty fumes over about 149C, and quite dangerous by-products when it decomposes at 232C. See https://en.wikipedia.org/wiki/Polymer_fume_fever

@TextGeek: Citation needed for 149°C. I've never seen a credble claim for dangers at such a low temperature, and it's contrary to all use in cooking, which is well over 200°C. The standard claim I've seen for where decomposition begins is over 250°C.

@R. -- It's been a couple years, but I believe I got those numbers from the Wikipedia page I linked. But the numbers there now are more like what you're saying, and I checked a few other sites and they agree. So I agree it should be safe below 250C or so.


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Why does print fall apart at beginning of top layer?
I'm looking for any idea of what could cause this problem. I'm printing (1.75 mm PLA @ 220 °C) a 14 x 14 cm box, sliced with Simplify3D. Relevant settings are 3 bottom layers, 3 top layers, 3 outline/perimeter shells, and 15 % orthogonal infill every other layer.
The first 3 layers print fine.  Here's the first (bottom) layer after removing the print and turning it over:

The infill (layers 4-10) also prints beautifully (see left side of photo below).
But the moment it starts printing the next layer (layer 11, the top layer of the bottom of the box), which should be solid fill exactly like layers 1-3, it starts underextruding and generally looking like crap:

The first time this happened, I figured the nozzle got clogged or the extruder gear started slipping. This is not the freshest PLA, so maybe it was a PLA quality problem. But the same thing happened at the same layer when I tried it again.  And again. And again. As soon as I cancel the print I can have it extrude 5 cm of filament and it's fine, no clogs...and if I immediately start another print it again perfectly prints layers 1-10.  So it doesn't seem to be the extruder, the nozzle, or PLA quality.  I can't imagine the "stress" of laying 7 layers of infill could screw up the next layer...
I just can't figure out how layers 2 and 3 could be basically perfect, but layer 11 is consistently a disaster, when they should be almost the exact same G-code (only a milimeter apart).  I looked at the G-code and it's basically identical for layers 3 and 11, including same feedrate (G1 F2250).
This is on a DeltaMaker printer with a new E3D Lite6 hot end.  Can add more details if needed, but basically I'm just looking for an idea of what could cause this.
Update: Just tried a different roll of PLA and got the same results.

This is completely normal, your first layer over an infill is never solid as there is no support under the layer, due to this lack of support and the heat it sags out. Increasing infill percentage (e.g. gradual infill at top), more cooling at this layer might improve the first layer above the infill, but the quality will never be as good as the final top layer.

Well 7 years and 3 months of printing experience later and this is a pretty embarrassing question!  As you say it’s completely normal, and these “flaws“ should be covered up by any following top layers - each layer improving on the next.  I tried everything except letting the print finish!

There are no dumb questions, not everyone knows this, you find it out when you stop the print too early, as you found out. Infill is usually printed fast, so the filament is hot, stretched and unsupported, then you get such layers. I have put down the comment because I felt the answer addressing "why" (as you stated in your question) the layer looks as such are receiving less votes than "what" you might do about it.

I doubt this is a printer or filament issue. Rather, I suspect it might be related to how your slicer handles bridging scenarios (which basically is what laying down layers over infill is).
You could try to:

Increase the infill percentage and/or use an infill pattern that provides better support for the top layer (so that it isn't allowed to sag as much). You will probably still se some sag, but that is usually covered up by the next layer. Adding print cooling might also help here.
Adjust the bridging settings in your slicer software. If under extrusion is the main issue, perhaps you could try to increase extrusion for bridges?

I am no expert with Simplify3D, and I suspect that the default settings actually might be pretty good. I would therefore try option 1. first. Perhaps someone else here can give a better answer related to your slicer. :-)

Does S3D allow for other infill patterns (you stated "orthogonal")? I suspect other patterns give better support at the same percent infill.

@CarlWitthoft, You are probably right that another pattern would give better support. I found this video on how to set the pattern type.

Spot on.  The low infill had worked for me on some other designs, so I assumed it always worked...but with this PLA at the higher temp I decided to run as part of a previous troubleshooting experiment - nope.  30% works perfectly.

The infill percentage is a bit low.
Even with infill percentages that are higher than 15% (I use 25%), a single layer on top of infill will not create a good top. It takes at least two and looks really good with three. The first layer is often patchy looking!
If you're stopping your print after one layer, and have more layers to go, maybe let it continue and see if you are more satisfied with it after the second or third layer.
If you only have one top full coverage layer in your model, then I believe you will need to configure one or two more.
Sometimes too high of heat will cause the layers after the infill to looks sparse and sag, so temperature (as always) is a factor for covering infill. :+)

Good point, but in this case the problem was beyond the help of additional layers, and I got to the point where I didn't need to see the other two before I knew the print wasn't working.

Two things. First for a first layer from infill this is not unexpect. This is why you do 3-4 shells with such a sparse infill.
Most of the time we also have the first layer at a slower speed. Often we will get to this point and the difference in flow can be contributed to the temp to speed ratio. Try increasing your temp, or decreasing your solid layer speeds.
I recommend starting with a basic calibration STL. You can find them on thingiverse. Start with single wall, upgrade to a square, hollow square, etc.
Also increasing either number of top shells and or infill percent will also help.
3D printing is all about balancing 20 settings. I think of it like a performer spinning multiple plates. That said all about baby steps.
But to answer your question. Ignoring that this is exactly what I would expect even from a well calibrated printer on the first layer post infill.
layer 1-3 is that the first layer is very slow. The extruder has built up a backlog of melted plastic. Assuming you are running too cold or too slow for some different types of printing (infill, solid, bridging, solid infill) you will slowly run out. Then suddenly you hit this solid layer and it needs a LOT fast. But it can only melt plastic 90% of what you need. Then less will come out. A good sign this is happening is if there is a lot of plastic shavings by the geared extruder. (if it can't melt then it stalls and the extruder shaves the plastic)

Thanks and +1 for "3D printing is all about balancing 20 settings. I think of it like a performer spinning multiple plates."  That's a pretty good description.  :-)


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Does the printing substrate have to be glass? If so, what size?
I am new to 3D printing. I have just put together my own 3D printer with some help.
I was advised I shouldn't print directly onto the aluminium plate - I assume it's aluminium.

The manufacturer did give me a piece of matrix board (i.e. no cooper at all) to print on. Will this work well?
If glass is better, does it have to cover the entire bed? My bed is 275 mm deep by 220 mm wide. I'm struggling to find glass for it that will come within the next few days.  The only custom cut was on eBay and it's going to take over a week to arrive.

Is this the aluminum plate that's bolted on top of the heater plate?  If so, yes you can use that as your base.  Common methods include covering with blue painter's tape or hairspray.

You can try putting a thin layer of paper glue (I use Uhu brand) directly on the aluminium. I use it on glass and can print PLA without heated bed.

Obviously being in a rush can limit your options, but here are a few thoughts:
Quick solutions:

Blue painters tape (as Carl mentioned) will work directly on your heated bed...assuming it's a flat piece of aluminum with the heating element under it.  Your surface does need to be flat.
Acrylic plate will work but is best with no heat, or low heat.  PLA sticks to it.  It's easy to cut and easy to find at local hardware stores.
Scrap glass is fairly easy to find for free and it's not that hard to cut...or buy some at your local hardware store and have them cut it.  Just be careful, it's sharp. You can sand the sharp edges (wet sandpaper) to make it safer.  No, it doesn't have to cover the whole plate, but obviously covering the whole plate would normally be preferred.

Better (but not as fast) solutions:

Buy some custom tempered glass.  I like One Day Glass because they're fast and very capable.  Like Tom says, many many people print on glass because it's nice and flat and stiff.  It's also easy to clean and holds up well.  You can print on the bare glass with many materials or use various preparations like PVA (glue stick or white glue diluted with water are popular), hairspray, or others.
Touch Screen Glass: Some people like replacement glass for tablets or touch screens because it has a hardened scratch-resistant surface.  I've not tried it, but if you can find one that is the right size, it might be worth a shot.
Specialty products: There are many many print bed products out there that promise an easier/better printing experience.  I've used a few that are okay...definitely better than blue painters tape, but I much prefer my current favorite...
My current favorite is PEI. Use a 3M 468MP adhesive sheet (it handles the heat well) to stick a thin sheet PEI (also sold under brand name Ultem) on top of your glass plate.  I got this idea from Lulzbot and it's what they use on all of their printers.  It works beautifully.  Common filaments stick to it while it's hot and release easily while it's cool.  For other filaments I just use PVA like I would over glass.  For material printing tips and settings that work well on PEI beds, check out Lulzbot's site.  When it starts wearing out or getting scuffed up, I just sand it with fine sandpaper and I'm good to go for another hundred prints or so.

The painters' tape can also be white, what matters it, that it has a fine coarse surface.

Printing on glass is very common because it is very flat and leaves a very smooth finish on the bottom of prints. The perfboard will also work fine, but is not an as common choice because prints are harder to remove from it.
Printing directly onto the heater PCB is uncommon since it is usually not flat enough and you may damage it while removing the print.

ok so if it's harder to remove from perf board, are there any tips you can give me

In Russia, a common coating for an aluminum plate is masking paper tape.
Instead of ordinary glass, we often use a mirror, it is smoother.
Hair spray, sugar syrup and beer are also used as adhesives. It is not joke - their residue is sticky and can be rinsed off.

good point on suggar - do you dilute it before using and how thin a coating? Dry it or on wet? Hairspray is known to work, as it is pretty much PVA.

I myself do not use sugar as adhesive. I need only PVA glue stick and a solution of BF-2 in isopropanol. BF-2 is the famous russian glue, unfortunately, I don’t know any analogues.
About sugar syrup, I read that it should be liquid (free to drip) and applied with a brush on a cold table.

I have been printing for over 2 years directly onto the 3 mm Aluminum heated bed platform using a touch of PVA based print adhesion spray 3DLAC or Dimafix (see e.g. this answer on question "Should you use hairspray on a metal bed 3D printer?
"). I've obtained best results with 3DLAC. Works like a charm! Always good adhesion and a very shiny and flat surface finish. I have not found any downsides of printing directly onto the Aluminum, I find it very easy as I do not have to fight that dreadful tape (application, bubbling, tearing, etc.).


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3D printer with a cartridge
What are the possibilities of building a 3D printer which uses a cartridge-style material filling rather than the conventional extruder setup? The idea of the cartridge is to eliminate the necessity of taking the material in spool form. My aim is to build a 3d printer which can take materials either in the form of pellets or any other shape. The materials that I want to work with are COC(Cyclic olefin copolymer) and polycarbonates.I have these materials in pellets so need to design an extruder and hot end setup which can directly use these and print . currently I have a Lulzbot Kittaz 3d printer with a single extruder( hexagonal end).  Any suggestions where should I start?

You've not provided the type of 3d printer you are considering. You do reference "conventional extruder" and "spool form" which leads one to believe that you are referring to FDM printing. Some resin printers are using cartridges, but that is liquid, not solid plastic. Your starting location should consider what form the material will be inside the cartridge and what form it will be outside the cartridge. Will you use liquid that hardens under light? Will you use binary liquid that has to be mixed in order to solidify? Powder fed by screw to be melted in the nozzle? Too much undetermined.

I think fred_dot_u is right on.  This is definitely an interesting question to discuss, but it's more of a brainstorming topic...I'll probably try to answer it anyway, but the question sort of defies a "right" answer.

My understanding is that the spools of filament used in FFF 3D printers are almost invariably produced from polymer granules, also called resin pellets, also called plastic nurdles. Some early (2006-2008) experiments with a GranuleExtruder attempted to skip that intermediate filament step.

Hi Veda! As Chris points out, your question encourages more or less a brain storming session, but no possible definite answers. For this reason, I unfortunately have to put your question on hold for being too broad for now. Feel free to make your question more specific so that there can be a single correct answer - this is the format that is encourages on Stack Exchange sites in general. Good luck!

Hi, i have edited the question to make it more specific. Can you please remove the hold?


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Poor adhesion only for first couple of inches
I have a QIDI Tech 1. It has a heated bed, and a cooling fan attachment. Whenever I print without a raft, the first inch or two of material laid down does not adhere to the bed, but the rest of the first layer is flawless.
I have tried speeding up and slowing down the first layer walls, but the problem remains. It also seemed to get a little worse when slower. I also tried not turning on the cooling fan for a bit to see if maybe the material was cooling too quickly, but that had zero effect on it.
I'd like to avoid using tape and other methods since the rest of the print is perfect, and the bed already has a material on it to aid adhesion.
What else can I try to prevent the dragging for the start of the print?

In addition to the answers, see if your gcode is heating the bed first or the extruder head first.  I recommend bed-first, because that allows the entire bed to equilibrate (not just around the thermistor) while the extruder is being heated.

I've had this problem in the past with a Flux Delta printer. The first attempt to resolve it was to always use a brim along with a raft. The brim will often have settings to allow number of passes as well as number of layers. If you are not using the brim to provide adhesion, you still can use it to prime the nozzle.
Later versions of the software allowed for start g-code which moved the nozzle to the edge of the print area and extruded 10-40 mm of filament, also providing for priming the nozzle.
You've not noted what slicer you are using. You may find there are suitable locations to position the head to an unused area, run a few mm of filament, then begin your print.
Amazon Q&A says your printer accepts g-code, which implies the slicer generates same.
In combination with a brim, you may have your solution. I've also found that you have a heated bed. If you have a cold spot on the bed, adhesion may be a problem, although I think that is not the case, based on your description.

I'm using the MakerBot slicer right now, which does put a line to clear out/prime the extruder on the front off the bed, but that doesn't seem to be enough. I don't have options for that feature. What slicer do you use for your printer?

I'm using the paid version of Simplify3D for my slicer. I did a quick check of your software and found that you can edit profiles in a text editor: http://support.makerbot.com/learn/makerbot-desktop-software/print-settings/editing-custom-profiles-directly_11972 and make very specific changes. I would suggest to create a backup of the document prior to making changes. I find there is a start gcode entry in the document. You may be able to make the necessary change there. There is also an Anchor setting that may be of value. I didn't see an option for brim or skirt (synonymous) for the slicer.

@fred_dot_u Good catch about makerware not having the brim or skirt function in their slicer (what!?).  Your comment about brim and skirt being synonymous may lead some people to think they're the same.  Brim is mostly intended for added hold down and it touches the print.  Skirt is mostly intended for nozzle purging and it doesn't touch the print.  S3D does it this way too.  :-)

Thanks for the clarification. I'd edit my error out but comments don't have edit feature. Reading the reference information for anchor in the makerware software makes me suspect that it's the equivalent of brim, but I don't have the software or related resources to determine that. I should have read your answer more thoroughly.

I'd recommend using the "skirt" function if you're not already.
The idea is to print a few perimeter layers around where your part will be, but not actually touching your part.
Most slicers support this and you can choose how much skirt you want to print.  This addresses the issue you mention, and it purges old filament that has spent too much time in the nozzle.  As an added bonus, it gives you a good indication that your print location, print height, and first layer adhesion are all good.


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Poor first layer bonding and bridging issues with Prima PETG
I have a roll of Prima PETG, I like the strength but I am having a few issues - the outside perimeter of the first layer often breaks away as a loose string (so it's not bonding with the second layer or perimeter next to it), small areas tend to go gloopy and also bridging is very poor.
Have you suffered from these issues with PETG and if so how have you gotten around them?

Hi! Your question is not a good fit for this site. This site is not intended as a "discussion board" where you can exchange experiences and opinions, but as a place to build an archive of (technical,answerable) questions and answers. Answers to your question will almost entirely be opinion-based (whether one filament is worth the additional cost over another is extremely subjective).

Tom is right.  Here are a couple thoughts to consider.  1) There are MANY polyester based filaments that have been optimized by various companies for 3d printing.  To me, they seem more similar than distinct, but there are real differences.  2)  Since polyester/PETG type filaments share many characteristics, maybe you could modify your question to ask about how to improve/solve something specific that you've experienced...your answers will likely have broad value to the community and apply to most polyester based filaments you may choose to purchase.  :-)

Updated, but, you will find most responses to many questions on this site are largely opinion based.  Hope this format is more acceptable :)

Hi, JBFUK! As pointed out by Tom and Chris, your question still encourages a "discussion board" with very subjective answers. You could try make your question better by boiling it down to it's bare essence. Perhaps by specifying the problem ("the first layer breaks loose (see image example)"), what you have tried ("I used three types of glue stick, but neither worked"), and lastly, ask for advice. This way, it is much easier for other users to understand your issue, and give you precise, useful advice! I have put your question on hold until you can make your edits. Good luck! :-)

Have you found & fixed the problem? If any of the answers helped you to get an answer to your question or come to your own conclusions then please do vote & accept an answer (using the tick button next to it). This helps us reduce the unanswered questions list & stops the question from being bumped once in a while. If you found another answer (than those already posted), please add that answer (& accept after 48 hours) to share your experience with the community. If you have not been able to address the problem please update your question.

Those are fairly common issues and you should be able to tweak your way into good prints.

First layer perimeter bonding: Slow down first layer to around 15mm/s with fan off to address that bonding issue.
Gloopy blobs: To address the gloopy blobs, slow down to about 40mm/s or even less, and be sure to use wiping...also, maybe increase your retraction length.
Bridging: Use full fan for better bridging...note that bridging PETG is just harder than many other filaments, but it can be done.  The reference below includes some more notes on bridging PETG successfully.

Ideal settings will vary based on your printer, your environment, and the characteristics of your specific filament.  PETG can take some tweaking so don't be alarmed by the gloopy blobs, excessive stringing, and poor bridging, just plan to spend some time tweaking settings until you find a good balance.
Here is a fairly good reference for further tweaking with PETG.
If you'd like more help analyzing your print settings here, consider posting your current settings, your printer model, your ambient temperature, and pictures.
I hope this helps!  :-)


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is PLA gasoline, diesel or chemical resistant?
can PLA be used to print out containers or other parts that are in direct contact with gasoline, diesel or other hard chemical substances? Will it start degrading when in contact with said chemicals? Should I use ABS for this?

I have used both ABS and PLA for diesel gas caps and oil plugs.  As well have made a gasoline funnel out of both.   Both have done well for me.
I have attach a link to a plastics resistance chart if it is any help.  Unfortunately it does not show testing for ABS for all.
I prefer the ABS only do to the fact some items I have made sit in the desert sun.
Plastic resistance chart

do you have experience with below freezing temperatures and using PLA for gasoline/diesel?

Only with the oil plug and the diesel tank cap as I have sent those types of items to my son and he live in areas where it freezes.   As for the funnels no experience with the cold.  But I will note I have had commercially made plastic gas cans and funnels in freezing weather and had them break do to the cold.  But no issues with the petroleum itself affecting them.


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Do I need a heated bed for printing PLA in an enclosed printer?
I am planning on building a large enclosed (Cartesian XY-Head) 3d printer. I want to keep the inital build time minimal and it is very likely I would need to build the ~50x50cm heatbed from scratch, because it doesn't exist in ebay.
The enclosure itself is not separately heated, but depends on waste heat from the printing process. The enclosure will eventually be vented outdoors with a 12V CPU vent via ducting (air flow unknown).
Do I even need a heated print bed, when I am planning to only print PLA?

"Waste heat from the printing process" is basically 0. The hotend takes around 40W, and the steppers (if they're inside your enclosure) are only about 20W each at best. That's a total of 140W which will not heat up a 50x50xZZ space up much at all.

that is useful information @TomvanderZanden - thank you!

The answer is "No" you don't need a heated bed for PLA but it does make the base layer a little easier to lay down and also helps with print removal post print.
PLA is a very easy filament to work with and the majority of PLA printers don't come with heated beds and suggest blue tape and/or elmers glue.
You may find that if you are purchasing very cheap/poorly extruded PLA, that things don't stick as well and a heated bed can alleviate some of these issues.

I was warned, accurately, not to head blue painter's tape above about 50 Celsius because it actually loses adhesion when warmed.  But if you go with a PEI sheet, adhesion increases with warmth.

In that case I guess having a heated bed for PLA is a must for me, because I want auto ejecting/part removal into a bin and I want the part to come off without much force.

I started a separate question to derisk the ramming action I am planning to use for auto ejecting:
http://3dprinting.stackexchange.com/questions/2921/printed-part-auto-eject-automatic-part-removal

$15 PLA which I use bends (not as much as ABS though) without heated bed. It even pops off sometimes.


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true color printing with CMYK+White (not 3-in-1 diamond head RGB)
There is this great hotend called a diamond hotend, which can be used to print in 3 colors and mix them into hundreds? of colors. This can for example be used with Red, Green and Blue filament to mix a RGB palette. They don't have to be these colors, but I believe RGB would give the maximum range of colors when constrained to 3.
However true RGB in physical printing would use separate colored voxels to create the appearance of a color, just like monitors display colors. As far as I know only HP Jet Fusion 3D printer uses this process, but it uses a process vastly different from normal diy 3D FDM printers.
CMYK is mixed physically like you would mix watercolors together to make new colors. It is used for printing on paper by all laserjet and inkjet printers (and in printing presses).
So that means even the 3 input diamond hotend is actually mixed like CMYK. Repetier firmware v92.9 has this built in with support up to 16 inputs for a nozzle, but Marlin firmware v1.0.x only supports 4 inputs per nozzle at this time.
Using RGB for the 3 inputs of a hotend, means the printing color palette lacks White and also it seems that CMYK would give a bigger range of colors. That brings our tally to 4 inputs. It still needs a white filament to print white, so that means 5 inputs. And while we are at it, probably a 6th input would be useful: like for printing black infill (to save using CMYK to mix into black) or for using transparent filament or elastic filament.
So why isn't there a nozzle with 5-6 inputs already? Could it be done? Are there such hotends already?
P.S These are just theoretical assumptions. I just discovered 3D printing and I am in the planning phase of building my first 3D printer, so I am a total n00b in this. Please correct any assumptions I got wrong.

Possible duplicate of What is stopping us from mixing 3d filament colors in an Extruder?

This is a specualtive "what-if" question. This site isn't really for brainstorming on possible new developments. Also note that some 3D printing techniques do offer full CMYK (the former ZCorp, 3D systems, Objet, MCOR,...) but they don't use FDM.

my goal is to find out if this type of nozzle already exists and I just suck at googling

Do not forget WHITE, adding black alone will not move any of the three individual color to lighter shades.    I posted my view on this in the similar discussion that Tom van der Zanden mentions.  If you want 5 or 6 nozzles then look at Palette.  But it does not do mixing just multicolor switching on the fly.

@TomvanderZanden it's technically not a duplicate as OP is asking about a different color delivery system. The link you posted was specifically with regard to using markers/pens to "paint" the filament. This question takes it a step further by asking if there is currently a system that beats the marker/pen setups with use of  the actual color ingredients.

You can find a full color hot end with CMYK+White if you look here https://www.reprap.me/diamond-fullcolor-hotend.html

although a short answer and probably breaking community guidelines, this is exactly the part I was looking/waiting for

You may be a bit misled here. First of all, you do not want "RGB" , as those are additive colors such as used when combining light sources.  You do want "RYB" (red-yellow-blue) or the more accurate CMY(plus K just to get a 'truer' black)  for subtractive colors.
Next, there's really no reason to attempt pixel-mixing. What should happen, ideally, is that pigments get fully mixed upon extrusion so that the desired color is actually in place. Pretty much any pixel-based setup will not "blend" into the desired visual perception.  And as you propose, you really need a White and a Black to adjust the saturation (take a look at the Wikipedia pages on Hue and Saturation color maps).
So I'm not convinced that separate extrusion heads will ever get you a decent color continuum.  I don't know if anyone has, or is planning, a multi-input, single-output head but I'd sure like one.

There's the Diamond head which combines 3 inputs and mixes them somewhat into 1, it costs around $30 on ebay. I've also seen plans for a 6-in-1, but no actual product. Thank you for the note about RYB :)

So whilst this is not quite what you were talking about I think this is the closest to the effect you’re looking for that I’ve seen.
https://www.xyzprinting.com/en-US/product/da-vinci-color
This da Vinci printer uses a CMYK inkjet to colour a white filament as its being extruded. This allows for very quick changes in colour as well a nearly infinite combination of colours.
This means it only needs a single extruder and hotend but obviously the hotend needs to be built to allow the injection of pigment from the inkjet.

The problem with your answer is not that it "is not quite what you were talking about", but rather that is not... an answer to the question being asked.  :)  Yours would be better suited as a comment to the question instead, as it is still likely to be of interest for the OP.  :)

this is indeed interesting. DaVinci saw the same gap in the market as me

@mac point taken I guess I made it an answer because OP didn’t say whether he was looking for a part he could use or just a solution to the problem. If it’s the latter than I think this is in fact an answer but I can see how it might be more appropriate as a comment.

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