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Not printing... wrong settings?
My printer is not printing.
I already had my first print but now it won't print. I think it has something to do with the settings (it's not heating up).
I am using Cura.
I load up the program and then save the file to an SD card and then put it in the 3D Printer.
How can I setup the program so that the printer's heatbed heats up?

Do the stepper motors run like it is trying to do a print, or does nothing start at all?

After you have put the SD card in the printer, you should use the printer's controls to navigate to the file stored on the SD card, and select to print it. Just putting the SD card in the printer does nothing. Are you doing this?

I "click" on start print but it deosnt heat up or try to print at all

Maybe you could edit the question to include the first few lines of the G-code file (up to the first 10 G1 commands or so).

Is it possible that Cura is creating incompatible G-Code for the machine? I thought that Cura engine could support multiple different "flavors" of G-Code. That might be a Cura setting if so. Could you specify more details of what you're doing and what machine you're using?

I don't think this is a Cura problem, its the printer firmware (I think).

Did you manage to resolve this problem?

There isn't really enough detail in the question to enable us to work out what the problem is. It would help if you shared your Cura settings, and a sample of the offending G-code. For now though, I'm voting to close this question as "unclear what you're asking" because there is no way to figure out what's causing your problem without more information. If the question is closed, you will be able to edit it to include additional detail, after which it may be reopened.

Yes in this case I would recommend a 3d printing forum or facebook group. We like to see more explicit questions. As this site really is not designed for back and forth conversation. Now if you question was "what are the steps to diagnose a printer." We would have something for you. That said, start from scratch, reflash the printer, check connections etc..

I wonder if there is a glitch in the firmware producing this unexpected result (which I think I also observed).
If you navigate to quick settings you should find preheat pla. Selecting this has little obvious effect (except for fan speed droop as the heater kicks in), but the target temps will now be 190C / 60C.
Print File seems to wait for the pre-heat to have reached a threshold before starting to run.


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What solder specs are safe to use when soldering wires to an Mk2a heat bed?
I've already asked which wires I should use, and I believe I have that covered now, but I was also wondering what solder / specs on the solder are considered safe when attaching my wires to my heat bed.  I have some solder here at the house, it's quite new (never been opened) it's Radio Shack 64-008 E 60/40 Standard Rosin-Core with 0.062 diameter...

Old-style lead/tin solder has a melting range of about 180 to 250 degrees (the transition solid to liquid is spread out). This ought to be fine for the bed (even at the hottest hotspot) but wouldn't be good in the hotend.
Modern electronics lead-free solder varies since there are several different compositions, but is typically a bit higher in melting point (by some 10s of degrees).
Special high melting point solder transitions around 300C, but you would only need to use this in very specific scenarios.

That solder sounds like it should be fine.
Any solder should work, the only difference you might find is some of the older solder will include lead. if you were overly concerned about safety you might want to check your solder doesn't contain lead. However, for the amount you are doing, even a solder that contains lead isn't going to be an issue.

Lead-free solder has some pretty significant disadvantages. It's much harder to work with, and over time may form "whiskers". On the other hand, lead is pretty darn bad for you.

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What causes the print heat to 'catch' on the part?
What would cause this effect, and how can it be avoided?
This is a PLA print, and it should look like this. I tried 215 and 225°C and both had the same effect. An earlier similar print at 220°C was not as bad but it still had some catching- it seems hit and miss and not strongly related to extrusion temperature.
Outside:

Inside:

I'm using a QIDI dual extruder printer with Makerware 2.2.2.89 software and these parameters:

Speed is 60/80mm/s.

Cooling fan? It seems that this is a bridging failure (or at least that initiates the problem). Cooler temp, or supports maybe?

@SeanHoulihane Thanks for your comments.  Bridging? You mean the fact it's curved inwards toward the top? There is a cooling fan, but I thought it was more important for ABS. Have to figure out how to control it. There did not seem to be any improvement with lower extrusion temp- it was actually worse (probably a coincidence).

Bridging meaning drawing an un-supported overhang. I think the way it's supposed to work is the extrudate freezes in mid-air, and clings on at the supporting ends. Hard to tell if its cause or effect, but it seems to be falling away. Also, the thingiverse listing says to use supports (which would be printed under the overhang, with a small gap. Check how this looks in the slicer.

Is the failure mode location something that can be associated with a specific point on the bed? To have the head catch on the print, the print has to be higher at a specific point, or the head has to be lower. The mechanical integrity of the head transport must be solid and the bed has to be level and not warped. How does your situation fit in this description?

The supports printed nicely under the hinge overhang. I assume the software didn't think they were required under the conical top.

@fred_dot_u That's a very good tip. I'll check the bed leveling tonight. It does seem to occur near one corner.

@SpehroPefhany, I believe you might have mixed the cooling strategies of ABS and PLA: use as much cooling as possible with PLA, and as little as possible with ABS. :)

I think that you should first verify that you have the latest firmware and a newer version of MakerWare. I experienced similar issues around that version of MakerWare and remember a lot of print errors came with it.
I believe the MakerBot Dual firmware is somewhere around 7.? and is no longer in development.
MakerWare is also no longer in development as a standalone application and seems to have been ported over to the MakerBot Desktop. However I've personally found v2.4.1 to be substantially more stable than v2.2.
I have not tested it, but supposedly the new MakerBot Desktop (v3.10) is compatible with the Replicator Dual "Original". I had tried an earlier version of MakerBot Desktop and reverted back to MakerWare 2.4 because I ran into issues with connectivity. However, I'm not certain it was an issue with software so much as the exploding voltage regulator...
It might be best to give the new software a shot and/or try v2.4 of MakerWare, if you can find it.
Here's the link to the latest MakerBot Desktop
Here's the release notes for MakerWare/MakerBot Desktop v1.0-latest (v3.10+)

Well, I downloaded it, got it work, leveled the bed and got exactly the same results from the new file.

Did you try Tormod's suggestion of reducing speeds? Check out my answer here on how reducing your print speeds may help. As well as adding additional "columns" in a different area of the build plate may help cooling of your actual part. Please let me know if you'd like me to elaborate.

I was just going to run another test, and cancelled it - changed minimum time per layer to 30s from 5s. Will let you know.

Reducing the minimum time per layer might make it worse. I would suggest making a dummy part, like a cylinder in the corner of your build plate and make it the same height as your part. Also, increasing the time value for the parameter mentioned should help.

As pointed out in the comments, what you are seeing could very well be related to lack of cooling:
You may notice that the irregularity in the print become more and more pronounced the further up you see. I believe this happens because the area that is printed is reduced gradually closer to the top, which in turn will give each printed layer less time to cool. (The frequent revisits of the hot nozzle will not allow the top layer to cool naturally.)
This problem is very common when printing models with small cross-sections, and are typically solved by:

Installing additional print cooling fans (cooling the actual print, not the hotend/heat sink)
Printing several items at the same time (to increase the cross-section)
Reducing print speed (gives more time to cool, but might not work for very small models)
Reduce printing temperature

If you can, installing additional fans and/or printing multiple objects at the same time are probably the most efficient solutions - in my opinion. However, either method would be worth exploring.
PS: When printing PLA, set your fans to full. ABS, on the other hand, does not like cooling.

Thanks. The fans were at 50%- "turn them off for PLA" is printed right onto the PC cover of heated bed of the machine, but that's not what the program does/did. I'll try 100% and see if it makes any difference, thanks.

@SpehroPefhany. It is very strange that the manufacturer suggests turning off fans for PLA. I know it is quite common to turn them off for the first couple of layers for better bed adhesion (also with PLA), but the rest of the model will look significantly better the more print cooling you have. (I did a test once with three print cooling fans for PLA and printed a full layer of 10 cm bridges flawlessly!)

I wonder if it was a mistake in translation. 'Open cooling fan' could mean either to me, but the clarification "Set Cooling Fan OFF" is unambiguous. Here is what it looks like.

Hmm, yeah. That could really mean anything. :) Anyway, if you struggle with adhesion, turning it off for the first few layers will help with warping. Most slicers offer this option. :-) Found this example

My struggles with adhesion are mostly in wrenching the $&$#$ part off the polycarbonate without breaking anything, though I did see some poor adhesion in supports when I cranked up the fan to 100%.

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Can you replace broken 100k thermistor with thermocouple - potentially blown analogue input as well
I have bought myself an I3 3D printer - it comes with a thermistor which is then placed into a hole in the hotend and held in place by a grub screw.
Sadly due to my lack of care I managed to crush the wires with a pair of vice pliers whilst trying to remove the nozzle as it was clogged.
I have since unblocked it but now every time I turn on the 3D printer instead of giving a minimum temperature error it says it's 260°C - even if it's left off all night and I unplugged the thermistor. Otherwise, it seems to be fine.
I want to know can I just replace it with a thermocouple and a Maxim amplifier board (the one that Marlin supports, I forget the name)?  The thermocouple I have in mind is one that has the junction exposed (see image below), does this matter?

I plan to re-route it in the firmware to use A15 instead as I believe I must have blown the analogue input, right?

I didn't understand how you conclude that the analogue input is blown. I think I'm missing something in your last paragraph too, it feels like you already answered your own question - or is the question simply about insulation of the probe?

Well i wanted to ask about the insulation. How can i use the thermocouple I already have? Since other ones arent exposed Also if ive possibly shorted the analogue pin out with the pilars. I suapect i have.

Thermostat and thermo couple are electrically different.

so you telling me the second image is a thermostat? please do explain the difference? It was called a thermocouple so I assumed it was a thermocouple but with a metal piece crimped on. So I already have a thermocouple similar to the first image. can I just stick in the hotend then wire it up to the max6675 then connect it to main board and  configure marlin to use it

@SeanHoulihane I don't know about thermistors, but thermocouples typically have an asymmetric two-bladed plug like the one shown above. At least all of the pre-made ones that I've ever used did and when I've fabricated my own, I've always connected them using those kind of plugs.

Thermistors and thermocouples are different animals.  A thermistor changes resistance based on the temperature at the junction.  A thermocouple generates a small voltage (mV range) which varies depending on the temperature.  Higher temps typically use a thermocouple because thermistors tend to not be as accurate at those elevated temps.
My printer uses thermocouples, and it appears that yours does also.  I'm not sure what you mean by "crushed", but you can check to see if the wires are shorted to the heat block or to each other.  It is unlikely that you've damaged the input to the control board by doing this.  Shorted wires can give the same readings as no thermocouple attached.  You can also get errors induced through ground isolation if wires are shorted to the heating block.
Changing this out for a different system with a different input amplifier sounds like a nightmare in the making, and I'd only attempt it if I could not fix the existing problem or find a direct replacement.


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Second layer: gaps, poor adhesion - why?
I'm seeing the following pattern on my Prusa clone:

The first layer prints OK, layer adhesion to the bed is good. The second layer shows the weird gaps. On larger pieces, or with an increased feed rate, it sometimes gets so bad that parts of the second layer detach and are dragged across the print. I get the impression that this effect is worse when printing in the "top left to bottom right" direction, but not as bad when printing in the "top right to bottom left" direction.
This occurs with multiple filaments and materials. I've already tried to manipulate the flow rate, temperatures and print speed, but gotten little improvement if any.
What might be causing this issue?

I wouldn't describe that as an "OK" first layer. The nozzle is either too far from the bed, or you're underextruding. Underextrusion also looks like the cause of your second layer problems.

@TomvanderZanden, to me that seems like a viable answer, and not a just a comment. :-)

Have you tried a different slicer? I like to use Cura, as even with the best settings on Slic3r I cant get anywhere near as good a print to when I use Cura.

Yes, I've switched to Simplify3D in the meantime, with much more consistent results. Too baad @TomvanderZanden didn't post an answer I could accept :-)

@vwegert Tomvanderzanden has added an answer now :) I think it would be beneficial to keep an eye on this question though, because an explicit answer would help others in the long run.

I wouldn't describe that as an "OK" first layer. The nozzle is either too far from the bed, or you're underextruding. Underextrusion also looks like the cause of your second layer problems.

Any ideas on how to fix under-extrusion in Slic3r, Cura, or whatever OP was using?

Your first layer is horribly misscalibrated as well.
You really should do all calibrations over. Including your firmware when your result is this bad.
Following. Let's just assume your firmware is set right. And that your flow is right as well. The second layer speaks loudly of overcooked dribbling plastic. You might have a jam. Maybe the factory left some metal shavings in the hot end. I've had it happen. Try taking apart the extruded. Make sure there are no obstructions. Clean the tip with a micro hand drill bit.
After that we will need more info. Post your settings. Your might have underflow (you set filiment size higher than it is) and have temperature so hot your are literally boiling the plastic and it is all dripping sparatically instead of controlled.
Having temp too high can increase carbonization build ups and creats Jams. Did you ever have a good print ? My money is on a partial obstruction.


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How to build a metal-based 3D printer?
I have a hypothetical question. From which parts can I build a metal-based 3D printer and can I buy those parts somewhere?

Hi, Bartosz, and welcome to 3D printing SE! I have put your question on hold for being too broad. This is because your question currently is too general, making it impossible to give a specific, correct answer. (For instance, someone might think you want to build a 3D printer out of metal, while others might suggest that you automate a furnace - two spectacularly different answers.) Please have a look at our help page for more information on how to ask here at SE. Good luck!

I think this depends on what you are trying to accomplish with the 3D printer.
I have seen people online build metal 3D printers from a robot arm and a welder this would probably be the simplest design and build but robot arms that can weld are expensive.
I have also seen that someone at MIT build a glass 3D printer by building a small kiln with a hole at the bottom and moving it around like a normal extrusion printer. This method might work for a metal printer as well if you could get the temperatures right. This might be cheap enough a hobbyist could do it as well because you just need the same parts as a normal FDM 3d printer just able to more more weight.
But with the same parts you could also do lost pla casting and that would be a simpler approach with a better end product.
But probably what you would be really interested in building would be a laser sintering 3D printer. Where a layer of powder is put down and then a laser melts part of the powered to join it to the model. For this the main thing you need would be the laser. I don't know a lot about how these printer work but the laser would need to be able to melt metal so I would think it would need to be very powerful and that would make it very expensive.


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How to build this part using 3d printing
I am completely new to 3D printing. I need to build a calibration plate, which I was told can be built using  vero back plastic and a 3d printer. But I am afraid I need to know more if I give this to someone for fabrication. In particular, I am wondering how to get the white dots on the surfaces. My question is probably ill-posed, but I am trying to get as much info as I can before I consult any 3d printing vendors. Thanks

The photo is too small to be clear about the entire objective and there are no dimensions provided. A quick google search returns nothing 3d printer related to "black vera plastics" other than a reference to vera bradley, vera wang and an obscure reference to a woven black carpet with white spots of increasing size.
Even within those limitations, one can certainly print a strip of black with white dots. One method involves a dual extruder printer, enabling two colors to be printed, one layer at a time. The black layer would be extruded with suitable holes and the white layer would be place within those holes.
Another method involves printing the black layer with holes, swapping out the filament with white and creating white plugs of appropriate sizes for the necessary fit.
You've used the term calibration plate, which implies some level of precision. Is the precision related to spacing, dot size, dot color, or a combination of the above?
Such requirements may make the cost slightly higher, but not excessively. I can print up to to 290 mm long strip, possibly longer by going diagonal on my 290 mm print bed, with or without the two colors done simultaneously.
If you require crisp edges to the white/black transition, the holes-and-plugs method will give best results and require a bit of post processing. It may be necessary to ream the holes to correct diameter and sand the plugs to fit. Dual extrusion rarely provides sharp delineation from one color to the next.

Hi many thanks for this and I am sorry for the plastic spec, it's vero back plastic. The spacing and dot size and the coordinates of the dots on three different planes have to be very accurate for 3d photogrammetry. Atleast now I know few keywords.

Note that this answer focuses on a completely different 3D printing technique than the "vero plastic" leads me to believe you're looking for. Vero is a material used in Statasys' objet line of 3D printers, which use a jetting technique while this answer focusses on FDM printing.

Thanks for the clarification, Tom van der Zanden.  Stratasys printers are professional level devices, far outside the affordability of my hobbyist interest, but none the less fascinating printers.

Well, does this jetting techniques needs any extra specs that I should be aware of.

Unfortunately, I can't answer the jetting specs part, but suggest that you might be able to get away with FFF/FDM printing if the vendor is willing to work with you regarding spacing and tolerance. Even though my printer is hobby-level, I could accomplish up to 290 mm length strips and probably give 0.5 mm accuracy using the plug and holes method. Because your objective is optical, it truly is a matter of black and white. My DAVID Scanner system uses white panels with black dots with similar accuracy requirements. Sign vinyl works well too!

What are the characteristics of the white dots? (That is, are the dots small raised bumps, do they denote where a hole will be drilled, are they integral to a piece-to-piece connection, etc...)
If these are small bumps that need to be added to the top of the black surfaces, your most time-effective solution is probably print the black component first (with placement references for where the white dots are to go), then switch materials and print the dots, and attach them to the black component.
Otherwise, you'll need a machine capable of printing in two materials simultaneously(ish). See some of the newer Stratasys machines if you have a good budget ha!

Thanks for your comment. The white dots are kind of flush mounted with the black surface, so they don't feel like bumps. Can you give me some more details about the method?

Absolutely. Depending on the thickness of the surface onto which they are being mounted, you could create an recess into the part, where each of the dots are to go, and print that whole piece out. Then switch materials to white, and edit the white dots such that when they are inserted into the recesses put into the black part, they stick out the desired amount.

Example: If the black part is .5in thick, and you want the dots to stick out .25in, create an indention in the black part, "extruded cut" into the part .25in. Then, print out the dots to be .5in each. Thus, .5in thick black part, with white dots that stick out .25in. (Adjust the math accordingly obviously!)

Lastly, apologies, I've just noticed that your question was already answered above. Good luck!


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Steel versus MDF/Aluminium Y axis plate?
I have purchased a P3Steel v.4 kit that, rather unfortunately, comes with a steel Y plate.

I understand that there may be interia, as well as stepper motor wear, issues related to the weight of the steel plate. Therefore I would like to substitute the steel plate for another material. I had considered aluminium, as recommended by the RepRap wiki - P3Steel/Frame Versions/ Version  4.0 :

We recomended use aluminum beds for y axis.

However, it was suggested, by a vendor, that I use laser cut 6 mm thick MDF, principally for reasons of economics and availablity, over aluminium.
I have subsequently found a supplier of 3 mm thick aluminium 200 mm x 300 mm Y axis plates, so availability is no longer an issue, and the slightly higher cost is not really an issue for me. However, I was wondering whether there would be significantly less interia if using an MDF Y axis plate, than with an aluminium plate.
I assume that the masses/densities of aluminium and MDF are comparable, and a magnitude less than that of steel.
I have found the densities of aluminium and steel:

Aluminium 2.7x103 kg/m3 (167 lb/ft3)
Steel 7.82x103 kg/m3    (488 lb/ft3)

[Source: Densities of Solids - Engineering ToolBox]
The density of MDF is given as 700–720 kg/m3 (43.7-44.95 lb/ft3), which is a magnitude less than that of aluminium.
[Source: Medium-density fibreboard]
There is the issue that MDF can eventually warp, whereas aluminium supposedly does not, although the OP of Wanhao duplicator i3 print bed support warped shows that warpage is possible with aluminium plate - see Is the weather a problem for MDF frames? and Would a steel, instead of an aluminium, plate be reasonable?1.

TL;DR
Considering the benefits of weight/inertia, stiffness and lack of deformation/warping:

Is the difference in density between steel versus aluminium and/or MDF, make it worth switching from steel to aluminium or MDF?
Is the additional weight loss of MDF over aluminium worth the risk of deformation of the MDF due to humidity/temperature?

Notes
1 I found this question after having written up my question, so I admit that there is a risk of duplicity of the answers. However, I am concentrating more of the comparison of aluminium and MDF in this post, rather than just steel versus aluminium. Also, my question deals with the Y axis heatbed support, rather than the heatbed itself.

Inertia is determined by mass, not density. I would imagine that an FDM support needs to be thicker than an equivalent aluminium one. Aluminium is only 3-4x denser than MDF, so between a 8mm thick MDF plate v.s. an 3mm Aluminium one the difference in mass is insignificant.

@TomvanderZanden - Ah yes, thanks. I had forgotten to mention the thicknesses of the plates. The aluminium, I believe is 3 mm, however, I am not sure what the thickness of the MDF is. I shall get back in contact with the vendor.

I have not used MDF for building a printer before; but, I have used it for other projects.  It has the advantage of being very flat (initially); but, it has a LOT of issues with moisture.  It is basically just a compressed slurry or water-based glue and sawdust.  If you expose it to humidity or water it will swell like a sponge.  I would not consider it for anything that requires a dimensional stability.  For that, Aluminum is your better bet.
Regarding the material properties of AL vs MDF, here is a good comparison:

Note that while MDF has about 1/4 the density of AL, it has a MUCH lower Elastic Modulus (1/17 of AL) For the same thickness, it MDF is MUCH easier to bend than AL.  Also note the strength to weight ratio of AL is also better.
Even at twice the thickness, my calculations indicate that, for the same load, 6mm MDF would deflect about twice as far as 3mm AL. Also when AL exists its elastic region it becomes plastic (bends) where MDF breaks.
Another aspect to consider is flammability.  There a lot of heat sources around an FDM printer and if you are planning on a heated bed, there is one right there under the bed.  Where MDF is hard to ignite, it is flammable and does not respond to heat well.  On the other hand, AL can handle temperatures over 1000 degC and is a great thermal conductor for a bed heater.
I would definitely choose AL over MDF for you printer bed.
Another option to consider it is using a bare PCB (like FR4).  The material is really strong (it is fiberglass), is relatively inexpensive, and is fire resistant (hence the"FR" in the name).  Some commercial printers use FR4 for their print bed.  One disadvantage is that is can sometimes develop a curl and there is really no way to get it flat again.

+1, very interesting, It is worth noting that the 6 mm MDF is twice the thickness of the 3 mm Aluminium.

Even at twice the thickness, my calculations indicate that, for the same load, 6mm MDF would deflect about twice as far as 3mm AL.  Also when AL exists its elastic region it becomes plastic (bends) where MDF breaks.

Note that another good option might be bare PCB material (FR4) - unless you want to heat it.

That's a good point. :-)  You should update your answer with the additional information in your comments, as comments are somewhat ephemeral and can be deleted at some point in the future.

@Greenonline I made updates, see what you think


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How can I determine whether my borosilicate glass is fake or not?
Is there actually a way to determine whether the sheet of glass that one has received from a Chinese supplier on eBay is actually a sheet of Borosilicate glass, and not just a piece of normal glass intended for glazing purposes?
Are there any laminations, or markings/features, visible under a certain light or if the sheet is viewed at a particular angle?
I ask because most of the 200 x 300 mm sheets on eBay are priced at around £16 - £26, but there are a few priced at just £10, which still claim to be toughened glass, although they do not mention the word Borosilicate, such as this one, 300x200x3mm 3D Printer Heated Bed Toughened Glass Clear Build Plate UK STOCK.
To paraphrase, "Usually if things seem to good to be true, then they are probably fake." However, I wondered whether it was worth a punt as it is only £10, and then if I would be able to verify its veracity once it was in my hands.

Good question, I worked a while in labs. I think borosilicate glass was not looking greenish from the side (but I am not 100% sure). Other than that, the density is lower than of regular glass.

Google turned up this thread: http://arstechnica.com/civis/viewtopic.php?t=96214
There don't seem to be any easy, definitive tests. You have two main options, both of which seem to require a fairly high level of laboratory skill (but nothing fancy in terms of equipment).
The refractive index of Borosilicate glass is very similar to vegetable oil (implying no reflection from a boundary if you have a pool of oil on the glass).
The density of the glass can be measured too, using a water bath. This should also be able to give a fairly accurate answer.
Stress testing seems the most reliable way to determine if you have a 'good' sample, but may be more expensive.

All you have to do is submerge your sample of glass into mineral oil. If it seems to disappear, it's borosilicate.

Hi and welcome to SE.3DP! Do you have a link, image or video to demonstrate this visual effect? In addition, please keep comments friendly... if you disagree with someone else's answer there is no need to denigrate it. You may also wish to edit your answer, and fix the typos. Thanks :-)

https://www.exploratorium.edu/snacks/disappearing-glass-rods

Some more details about a suggestion made to the answer on How can I determine whether my borosilicate glass is fake or not?.
Submerging the glass in mineral oil should make it disappear if it is borosilicate glass, as demonstrated below. This phenomenon is known as the "index matching" effect. The index of refraction of borosilicate glass is n=1.47, and that of mineral oil is also around n=1.47, depending on the type of mineral oil used. However, as mentioned in this comment, other types of glass might have a similar or close refraction index, making it hard to distinguish borosilicate from non-borosilicate using this test alone.

The borosilicate glass and the oil have roughly the same index of refraction. When this beaker is immersed into a container of oil, the beaker becomes invisible.

Source: The Disappearing Beaker Experiment

This is true for most glasses other than high index optical types.  Pyrex and window glass have nearly identical refractive index.

"toughened" glass,

Lead, cadmium and barium would have that effect. It goes without saying that you wouldn't want that kind of glass anywhere near your neighborhood.
Even those items that mention borosilicate glass in the product description may have never seen any boron.
Some studies have found that more than 90% of items sourced from China are fraudulently labeled. There is no enforcement.
While stats say nothing about any particular sample, I'd certainly keep them in mind.

It might be worth sharing some of said studies - also while it says what else the glass could be, it dosen't really help OP with working out if its borosillicate glass.

Hi and welcome to SE.3DP. Can you provide links, sources to back up your claims? It goes without saying that you wouldn't want that kind of glass anywhere near your neighborhood. Pyrex will be found in your kitchen probably. Some studies... what studies? Do you have a link? Your answer would have more worth with sources. Thanks. Also, you aren't really answering my question, but rather questioning the morals behind Borosilicate. I just want to know how to check that it isn't just plain old vanilla glass.

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Recommended settings for ColorFabb Copperfill Filaments on a 0.25 mm Nozzle?
I switched out my 0.4 mm Ultimaker 2+ Nozzle the other day for the 0.25 mm and started using a ColorFabb Copperfill 2.85 mm filament. I am having some issues with it clogging and sticking to the bed for larger prints:

Current settings are:

Extruder Temp: 230°C
Flow Rate: 110% (increased it from 108% get more consistent output)
Bed Temperature: 70°C

I thought it might be a calibration issue since I could see it skipping certain sections and slowly collecting excess material on the outer nozzle, so I recalibrated the bed but I still ended up with a blocked nozzle after about two hours of running. Not too sure if there are other settings I need to take care of. Any suggestions would be great!

A more general title might help you get more visibility here. I doubt its specific to the exact materials, this is maybe more a question of debug after changing stuff.

It looks like a problem with feeding filament. It could be good to know if you did try such big printouts before but even if - from your picture it looks like on far end there is too less filament but on near end it's too much of it (because of 110%). And near the big circle it looks better even on far end. And there are "waves" close to big circle.
How is that possible?
Assuming that your extruder works well it might be caused by bending bowden tube. If your filament is not slick enough - in some settings (positions/arrangements) of bowden it might create enough friction so it doesn't flow with proper rate. It might be also caused if your bowden tube was bent too much (broken).
To be sure please try to print 4 smaller (5 cm in diam) circles on bed's corners and the one in the center. Just one layer of course.
How to fix the issue?
In my opinion you could try to slow down whole printout. Try to print such big circle with 30% of regular speed. I'm pretty sure you'll get proper results.
Try to check if filament goes smoothly thought the tube. Check if it has proper inner diameter. You can try to clean up a tube inside if it's not perfect clean or change a tube to new one. I know it was probably ok for recent filaments but maybe this one is more "demanding" ;)

I agree it could be a feed problem. It might also relate to the filament getting stuck as it comes off the reel somehow (extrude speed related maybe)

Lowering print speed is probably a very good idea. Remember that using a smaller nozzle will markedly increase the extrusion pressure at the nozzle (and therefore also the extruder gear). You can find a suitable printing speed by by assuming your volumetric pressure is constant (using parameters from a previous print with the 0.4 nozzle), lowering your extrusion width to match the new nozzle, and then balance print speed and layer height accordingly. Good luck!

It appears to have been the over-extrusion because it was only recommended for 108% flow. I've tried large prints as well, and upon closer inspection it appears that all of them have the same marking pattern as above, but it's not apparent during printing. I suspect it may have something to do with the glass bed as the other prints were on 0.4 mm nozzles and I've recalibrated a number of times already. I've lowered the flow back down to 108% and although it's still not perfect, it doesn't look too bad :)

@ITTsoi it could not be too hard to check if your glass is ok using bubble level or... other piece of glass ;) (keep in mind it can bend while hot). But I still think these "waves" suggest something else than curved glass.


text:
Do aluminium PCB heatbeds reduce hotspots?
TL;DR

Do aluminium PCB heatbeds suffer from hotspots as much as standard PCB heatbeds, or is the presence of hot spots smoothed over by the fact that the PCB "substrate" is aluminium, and so its thermal conductivity helps spread the heat more evenly?
Or, conversely, could the effect of the hotspots be magnified, and actually made worse?
Which has fewer hotspots, MK2A, MK2B, or MK3? (I'm not sure if this should be a separate question)

I would have also asked whether aluminium PCB heatbeds are worth the additional cost, over standard PCB heatbeds, but for the slightly less common dimensions of 200 mm x 300 mm, the costs, of an aluminium PCB heat bed, are roughly the same as standard PCB.
Some thermal imaging pictures, comparing standard PCBs with aluminium PCBs, would be appreciated.

I am keen to buy an aluminium PCB heatbed for my P3Steel v.4 printer, which has a larger build area of 200 mm x 300 mm. So, after some searching, I found this MK2A: MK2A 300x200mm Aluminum Heated Bed Hot Bed for RepRap 3D Printer 12V + Wiring + NTC 3950 Thermistor - Upgrade you Prusa i3 for LARGE Printsize, or this cheaper MK3, Anycubic Dual Power MK3 Heatbed 300*200*3mm Aluminum Heat Bed 12V/24V Perfect for Prusa i3 3D Printer.
Note: this is not a shopping question, I am merely providing a background to my questions.

While the RepRap wiki is full of information, the information can be rather piecemeal and incomplete. Cases in point being the two pages on heatbeds:

Heated Bed, and;
PCB_Heatbed.

As stated in the former link, on the section on Metal print beds, PCB based heatbeds can suffer from hotspots, and that is why, apparently, it is sometimes preferrable to use a subsequent aluminium build/print bed on top of that, en lieu of glass plate, in order to even out the hotspots, as the aluminium's greater thermal conductivity helps smooth out the hotspots, by distributing the heat more efficiently than a glass plate can. However, it doesn't describe the heating effect of just a single aluminium PCB heatbed.
The section, in the latter link, on Aluminium heatbeds, where the heating circuit is printed directly onto the aluminium, rather than a standard PCB (on a non-conductive substrate), makes mention that the print can be made directly on to the aluminium, without the need of an additional glass plate, resulting in a lighter print plate, and hence faster print speed. However, yet again, it is not particularly clear, or explicit, when it comes to heat distribution.

A thermal image of my aluminum heated bed does not show hotspots, although the edges are cooler than the majority of the center.

Without comparison to normal heatbed, this isn't so useful information...

The question is about whether aluminum hotbeds have hotspots. What is a "normal heatbed"? I have only used aluminum beds.

authors: Алексей Марфутин


text:
One corner never sticks
I am new to 3D printing. I thought that the black surface of my print bed was supposed to keep things stuck without additional tape, spray, etc.  However, every time I print something, this same corner, and only this corner, detaches.
Any advice on how to fix this?

Monoprice Makerselect V2
Hatchbox PLA
Temp 195/50

This is very likely caused by an uneven bed. It's probably lower in that particular corner: the nozzle is further from the bed, so the filament isn't squished down as much and therefore releases more easily from the bed.
Your bed should have 3 or 4 screws that you can adjust, you should loosen the screw in the corner that is giving you trouble.

That seems to be the problem.  The print bed has a significantly low spot in that area.  thanks.

I'm paranoid, so I often overtape the brim to ensure it doesn't come loose.   You might also consider raising the head temp a bit so the first layer is less viscous and will microflow onto the bed better (more adhesion)

After trying to deal with this for a while I realized aluminum warps with heat and the print surface will never be flat.  I use a glass plate now and it is much better.


text:
How to build my own Cura GUI?
I am trying to create my own Cura GUI. I am constantly getting the error:
UM module not found.

Do I need to see a UI file?
I think I am wrong.
I've installed Python, pyqt5, numpy, scipy, but I do not understand why the constant UM module was not found.
I know I'm doing it wrong somewhere but I can not find my mistake.
I believe there are people who will help me. There are people who know how to do it. Will you help me? What am I supposed to do?

I'm voting to close this question as off-topic because it doesn't appear to be about tools / devices but rather general programming issue

Can you edit your question to include the entire error? As it stands the error has no context. UM probably stands for UltiMaker, (although it could be Ubuntu Mate). Are you using Uranium? Have you imported the UM module? Please provide more details, in your question. Python verison, OS version, etc.

@darthpixel - is it possible to migrate this question to SO, maybe? However, the OP may be more likely to get an answer here, as there may be more chance of finding 3D printer coders here, than on SO.

Have you done basic google searches? I did a few (1 and 2) and found some links that might help.

This question has been moved to Stack Overflow, since the actual issue is not related to 3D printing, but rather general programming.

@SamuelLiew How come this post was migrated in 2016 and only had the migration rejected today?

@Trish 3dp mod requested for it to be reverse-migrated & approved by CM

UM could stand for UltiMaker. I think that you need to either:

download Uranium;
install the UM package;
import the UM package, or;
need to add it to your path (PYTHONPATH).

You may find your answer here: help needed: ImportError: "No Module named UM" in Eclipse #510.
The two things that you seem to need to do are:

Get Uranium from https://github.com/Ultimaker/Uranium.
Add the path: PYTHONPATH=/path/to/uranium/repo cura_app.py

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


text:
How much insulation do I really need?
I have been looking at cork sheet insulation for my 200 mm x 300 mm aluminium PCB heatbed, by I am not entirely sure how thick it should be. There seems to be a trade off between losing a few millimeters of print height, and providing adequate installation.
I have seen 10 mm thick table mats, and then 5/3/2 mm thick cork insulation tiles. On some forums people say they use two 2 mm sheets beneath the aluminium heater and then another 1.5 mm aluminium plate under those, to hold it altogether (source: Re: Is a cork board necessary under the heated bed?).
Hopefully this does not come across as a how-long-is-a-piece-of-string type question. I am just trying to get the right amount in the first place whilst spending as little as possible, and keeping the mass/volume and height down. If someone else has already gone through the empirical adjustments themselves, then it might save me the time and expense of having to test various configurations.

Would just 2 mm thick cork backing be sufficient?
Is 10 mm overkill?
Does silver foil backing help considerably, thereby enabling one to reduce the thickness of the cork?

Cork is bloody cheap. Why worry  -- other than the fact that it's flammable. All that's needed to start a fire is having the thermistor fail or come loose. I'd use a flameproof material if you're going to insulate.

@CarlWitthoft - OK, thanks, this is the first time that I have really given thought to the flammability issues, although I had read that cork is preferable to silicon/rubbery insulation, due to less noxious fumes being given off.

If you really want to go all out for insulation, buy some aerogel!

@tbm0115  - :-) That really does look top notch, but is, unfortunately, a bit pricey.

@Greenonline I have to admit that you'd have the coolest looking 3D printer with some of that Classic Silica Aerogel insulating your machine!

@CarlWitthoft - As the ignition temperature of cork is 300°C, I wonder if there really is a fire risk. Do you know of any examples of burning, or scorching, of cork, when used as a heatbed insulator? Please see my question Has anyone experienced scorching or burning of cork heatbed insulation?

Burning cork is difficult even when you WANT it to burn... Cork is the outer layer of trunks and has specifically the goal of protecting the plant from fires. I would say almost no flame risk.

Since 50% of the bed is uninsulated, you're definately into diminishing returns as soon as you start adding any insulation.
With that area, I think you are looking at 1.2W per kelvin for a 2mm thickness.
I'm guessing a bit with these powers, but roughly, maybe from 100 W un-insulated, 75 with 2mm, 60W with 4mm. You can get a reasonably accurate measure of the power by looking at the duty cycle of the heating element.
Actually, its not clear if your primary goal is to reduce energy/maintain a very high temperature, or speed the initial heating. You can place a temporary sheet of cork on top of the bed (preferably extending over the edges to prevent convection) and this will significantly improve heat-up times.

Many thanks for the answer. I think that I see what you mean, but just to clarify a few points: By diminishing returns, you mean that each increase in insulation thickness gives a correspondingly reduced increase in actual insulation (which, I guess, would make sense)? Are the figures of 100/75/60 W relating to the power used to maintain the heatbed at the same temperature (i.e. 70°C)? Without (necessarily) wishing to get into the mathematics too much, are those figures for the power, guesstimates based on experience or did you arrive at those figures using a formula?

Yes, doubling the insulation doesn't double the power saving. The numbers are guesses, I need to work more on the maths for a real answer.

Also consider cork on top of the bed during heating.

Yes, that is a good idea... I remember reading somewhere that someone suggested even corrugated cardboard helps.


text:
How to directly send G-code to printer from a Linux terminal?
Should it be possible to directly send G-code to the printer serial connection using pipes under Linux?
Example:
echo M106 > /dev/ttyUSB0

My controller runs at 250000 baud, I have tried setting the TTY baud rate to 250 kBd with:
stty -F /dev/ttyUSB0 250000

But, unfortunately, this particular baud rate appears to be unsupported under Ubuntu, giving the error:
stty: invalid argument ‘250000’

For direct low-level printer control from a terminal, without specific software, I found the following solution with full credit thanks to user: http://stackexchange.com/users/6463673/meuh
Sharing here as may be of use to other users in the 3d Printing community, and I was unable to source a "complete" solution to this elsewhere.

Step 1)
Create a custom python script that allows you to set arbitrary baud rates (make executable with chmod u+x).
#!/usr/bin/python
# set nonstandard baudrate. Original Question: http://unix.stackexchange.com/a/327366/119298
import sys,array,fcntl

# from /usr/lib/python2.7/site-packages/serial/serialposix.py
# /usr/include/asm-generic/termbits.h for struct termios2
#  [2]c_cflag [9]c_ispeed [10]c_ospeed
def set_special_baudrate(fd, baudrate):
    TCGETS2 = 0x802C542A
    TCSETS2 = 0x402C542B
    BOTHER = 0o010000
    CBAUD = 0o010017
    buf = array.array('i', [0] * 64) # is 44 really
    fcntl.ioctl(fd, TCGETS2, buf)
    buf[2] &= ~CBAUD
    buf[2] |= BOTHER
    buf[9] = buf[10] = baudrate
    assert(fcntl.ioctl(fd, TCSETS2, buf)==0)
    fcntl.ioctl(fd, TCGETS2, buf)
    if buf[9]!=baudrate or buf[10]!=baudrate:
        print("failed. speed is %d %d" % (buf[9],buf[10]))
        sys.exit(1)

set_special_baudrate(0, int(sys.argv[1]))

Step 2) Run the script to set your baud rate.
./set_custom_baud_rate.py <> /dev/ttyUSB0 250000

Step 3) You can now monitor your printer output in a terminal window simply with:
tail -f /dev/ttyUSB0

Step 4) And finally, open up a new terminal window, and you can directly send M or Gcode to your printer; example:
echo "M115" >> /dev/ttyUSB0

Can I ask you how is possible that this script works? I don't understand why you use <>, at first I thought was a typo, but modifying the script and opening the serial directly doesn't modify its baudrate.

<> on unix opens a file read+write mode, without truncation, and creates the file if it doesn't already exist. i.e system call: open(filename, O_RDWR|O_CREAT)

For example, cat < foo.txt it will print the contents of foo.txt, or fail if foo.txt doesn't exist.  Whereas cat <> foo.txt,will also print the contents if it exists, but will create the file if it doesn't already exist.

I know what <> does, but I don't understand why this works for the baudrate: you are setting the baudrate of the file descriptor 0, i.e. stdin not for the serial port.

My understanding is the baudrate is simply the first argument to the script, (i.e sys.argv[1]).  If you were to modify the script and hardcode a baudrate, and/or open device using the python equiv. of  open(filename, O_RDWR|O_CREAT), then I, too, would be surprised if that didn't work.

@gipi The "<> /dev/ttyUSB0" argument defines stdin and stdout for the script.  When the script operates on stdin, it is operation on /dev/ttyUSB0.

This didn't work for me, nor this guy: https://3dprinting.stackexchange.com/questions/10612/sending-g-code-through-usb-serial-doesnt-work-ender-3?noredirect=1&lq=1
The tail command doesn't output anything
The printer seems to thing "ok" is an unknown command, which is its response, right? So why is it receiving its own response as a command?

you can use screen for that. Open a terminal window and type  screen /dev/ttyUSB0 115200 The general form is  screen serialdevice baudrate You will then see everything that the printer sends. Everything you type will be send to the printer.

Thanks!  Though does that work with non standard baud rates e.g 250k?  I suspect not (at least with Ubuntu/Mint), but that it would be possible to combine the above script, with screen command as per your suggestion.

The accepted answer didn't work for me. Everything received on the serial port was repeated back to the serial port, sending the printer into a confusing loop. There is more information about that in this answer: https://unix.stackexchange.com/questions/42964/unexpected-results-testing-serial-loopback-using-echo-and-cat
The key is to use a command like this to prevent certain line termination characters from repeating themselves: stty 115200 -F /dev/ttyUSB0 -echo -onlcr , where 115200 is your baud rate.
Here is what I did:
# 1. plug in printer
sudo chmod +777 /dev/ttyUSB0 # 2. allow access to printer USB permissions, add user to dialout or tty is better
stty 115200 -F /dev/ttyUSB0 -echo -onlcr # 3. set serial port baud rate, might be 250000 for you
cat -v < /dev/ttyUSB0 # 4. get printer output

Then in a new terminal:
   echo "M119" >> /dev/ttyUSB0

This will give you a real console.

Can you please share what flavour & version on linux you are using that this failed on?  (It worked on mainstream distributions - Ubuntu & Mint - at time of publishing.  Perhaps we can isolate why it wasn't successful for you.  I note your solution is for baud rate 115200, are you able to verify this works for baud rate 250000?

Can confirm the previous answer works on Ubuntu 18.04, and IIRC Mint before that (version unknown, formatted).  Not sure why it's failing on 16.04.  Thankyou kindly for posting another answer that works for you and other people - always great to have multiple working answers to help as many people as possible, cheers!

Actually it still repeats itself on 250000. So to get stty to stop the repeating, it seems like 115200 is needed

250000 is a non standard baud rate. In my case, 115200 works find with standard linux tools - but in order for 250000 to work, I needed that script posted in my answer. On my machines, 250000 works with that script.

Thank you this was super helpful

I spent a number of hours trying to work out why my Creality Ender Pro was ignoring me when I sent it serial data over USB from a Python app. Google searches trying to find a solution that were not talking about encode() and decode() all seemed to lead me to this thread.
I installed Minicom as per the video link, and all worked as it should, but I still failed to receive a reply in my Python implementation, I could connect and read the serial sent from the printer but nothing append when sending back to it.
After a few hours scratching my head I realised that the printer reacted to input as it received each new line \n character that I was failing to add to the end of each command sent so the printer was just sitting waiting for me to finish transmitting my line end that never came.
self.serialPort = serial.Serial('/dev/ttyUSB0', 115200, exclusive = True)
lines = self.serialPort.read(self.serialPort.in_waiting).decode().splitlines(False)
line = line + "\n"
self.serialPort.write(line.encode())

Hopefully no one else is as stupid but to save anyone else like me time, I would like to point this out here.

This is sort of "me too" answer reacting on some other answer. Which link are you referring to? This answer could be better posted as a comment to that answer.

i tried to move it but it said "you must have 50 rep to comment"

Please shorten the answer and indicate to which answer you'd like to respond in a comment, moderators can move it for you.

This forum page  strongly suggests you should be using setserial for a port, not stty , which is for terminals.  I'd give the code snippets there a try.
Alternatively, stackoverflow has a similar discussion, with somewhat more complicated modifications.
Are you sure you can't talk with your printer at a lower baud rate than the maximum capability of the printer-end?

You can't lower Marlin's baudrate without recompiling the firmware, I believe.

@TomvanderZanden bummer :-(

I could not get setserial to work on raspberry pi zero w. But since stty -F /dev/ttyUSB0 500000 works (and 250000 doesn't), I decided to change the baudrate on my printers. I changed the baudrate to 500000 in Marlin's Configuration.h after downloading/unzipping the printer configurations and recompiled/reuploaded. Works great now.

That's work solution:

you need 2 terminal, one for in and another for out flows

From [help]: Provide context for links
Links to external resources are encouraged, but please add context around the link so your fellow users will have some idea what it is and why it’s there. Always quote the most relevant part of an important link, in case the target site is unreachable or goes permanently offline. Without the video, in case of link rot, this answer has no value for the future, please describe how the video poster got access to the printer from Ubuntu, that would make a great answer!


text:
What grade of wire is required for the heating element on a J-Head extruder?
I have a large resistor that goes in my J-Head extruder. It's grey, and it came with the extruder.  I'm uncertain as to what grade of wire I need to solder to it.  It being one of the elements of the system that heats the hottest, I would think that it would be important to find out what sort of wire is the correct kind to use on it, since heating elements require a lot of electricity.
Also does the solder type I use matter?

There are a number of things to consider:

Wire Gauge: a typical 40W, 12V heater draws around 3A. 24 AWG or lower would be appropriate (copper wire, CCA will require thicker gauge).
Insulation: the part of the wire close to the resistor leads might get too hot for conventional PVC installation. Consider using silicone, teflon or glass fiber insulation instead, especially near the heating element. If the resistor's leads are long enough they might stay cool enough for regular PVC insulation, but make sure you insulate the part of the leads closer to the resistor appropriately.
Solder: if close to the heater itself, the solder might melt. Consider using silver solder, or using a mechanical connection (ferrule/crimp) instead. Again, this might not be a concern if the leads of the resistor are long enough.
Flexibility: given that the extruder (probably) moves a lot, use flexible wire (stranded, not solid core) and provide strain relief (especially near the connections, and avoid creating too sharp bends).

Finally, resistors have fallen out of favor compared to ceramic heating elements. Since they are inexpensive and solve all of the above problems (the leads are already attached and appropriately insulated) consider using a ceramic heater instead.

Agreed on all points, though I avoid Teflon very near the heater. Teflon becomes quite dangerous above 350C, but it also has smaller safety issues above 250C (see https://en.wikipedia.org/wiki/Polytetrafluoroethylene#Safety). You'd only hit 350C if there's a serious problem (such as a thermistor falling out of its mounting); but 250C is pretty close to normal extrusion temperatures, so some caution may be appropriate.

The physical size of the resistor is irrelevant.  What matters is the total power (and in particular, current) the head will draw.  Once you know that, there are plenty of tables on the web that'll list max amperage vs. wire gauge.  When in doubt, use a larger wire :-) since we're only talking about a couple of feet length; cost is minimal.
As to solder: so long as you're not selling the printer, you don't need to meet any RoHs requirements. Use whatever you want.

If you use wire at least as thick as the resistor's own leads, you should be fine....


text:
What is the purpose of asterix (*) in Gcode?
Doing some low level monitoring, the following sequence is sent to the printer:
N0 M106*36
N1 G28*18
N2 M107*39

This sequence just turns the fan on, homes the printer, then turns the fan off.
Question: What is the purpose of the asterix/star/(*) and the two succeeding digits on each line?

asterisk - Asterix is a character in a cartoon series.

@AndrewMorton So that would make the gcode the Romans then - with Asterix being their checksum, stopping corruption in his local area?

Hmmm... maybe. The Romans did build a lot of things, like a 3-d printer does.

That is a checksum. It's added by the host software to the G-code, to allow some basic verification by the firmware that the G-code was transmitted unchanged. It doesn't change the meaning of the G-code, and what your sequence actually represents is just M106, G28, M107. The N0,N1,N2,... are line numbers, and the combination of line numbers and checksums is used to request a re-send of any lines that were corrupted during transmission.

Do you happen to know the checksum algorithm used here?

In Marlin, all the bytes for the individual characters are XOR-ed together, and the result should be the same as the checksum.

Just XOR: byte checksum = 0;         byte count = 0;         while(instruction[count] != '*')                 checksum = checksum^instruction[count++];


text:
3D printing and coating of heat-resistant objects, such as a turbine blisks or blades
Is it possible to 3D print an axial turbine 2 - 4 inches (50 - 100 mm) in radius, capable withstanding temperatures about 800 - 1000°C and rotation speeds of 100 - 120 x 103 rpm?
How expensive is that? Is it cheaper to mill such a turbine from a whole piece of alloy?
What technologies and materials should be used?
Are Inconel alloys suitable for 3D printing?
Are there any titanium alloys suitable for this task? I've read titanium is rarely used in rapidly rotating parts due to its ability to ignite if mechanical failure occurs and rotating blades touch the casing. Do titanium alloys still have this drawback?
Is it possible to make disk of titanium and blades of Inconel, and have them welded (considering heat expansion)?
How blades or blisks can be ceramically coated?
Thank you!

Welcome to 3D Printing SE, this is a great topic that hasn't come up too much here on 3D Printing SE! However, there are too many questions in a single question here. Please consider breaking this up into other question posts to avoid having this post closed due to "unclear what the user is asking" issues.

You ask some very interesting questions! Firstly, when researching topics such as this, you will have far more luck using 'additive manufacturing' as a search term rather than '3D printing'. In the professional industrial environment, '3D printing' is not a term that is really used to describe the manufacturing you are talking about.
Selective laser melting is the additive manufacturing process most suited to metallic aerospace parts. Inconel alloys can be processed (e.g. IN718 being one of the easiest) along with titanium (almost exclusively Ti6Al4V). As for manufacturing turbine blades and similar parts, you might find this interesting: Additive Manufacturing - Breakthrough with 3D printed Gas Turbine Blades.
Titanium is not typically used in high-temperature sections of gas turbines, but will be used in larger, cooler components such as fan blades, where it's strength to weigh ratio is a benefit (less mass to rotate = better fuel efficiency).
Coating of high-temperature nickel superalloy components is usually performed with electron beam physical vapor deposition (EBPVD) or thermal spray such as high-velocity oxy-fuel (HVOF); each process has certain characteristics that dictate when/where is it used.
This is only really a surface depth answer to your questions, but it would be impossible to answer fully here!
(My experience: PhD student using selective laser melting with aerospace alloys)

Thank you for your answer! Still there is one important thing I'd like to know: how expensive is additive manufacturing next to milling this kind of product?

That's very difficult to evaluate. Overall, the cost of manufacturing a turbine blade via additive manufacturing (AM) will be higher than via casting (the conventional manufacturing method). However, AM can add value through complexity, e.g. internal cooling channels or lattice structures to minimise weight. So really, it is a cost-benefit analysis rather than a straight costing. (Rough example) machining the outer form of a turbine blade via CNC milling may cost 10% of that of an AM part. However, even a 1% fuel efficiency increase over the component life blows this cost out of the water.

The overall answer - it is almost always cheaper to stick to conventional manufacturing (e.g. milling), but the aim is to leverage the advantages of AM to improve (add value to) your component. Taking an existing CAD file and simply printing it is pointless - use the principles of 'design for additive manufacturing' to really make use of the technology.

What's the difference in designing for AM? What special features this needs? Or it is about thinking how to improve component design using newly available manufacturing methods?

How thin could cooling channels be? Considering micro-turbines with mi.. ok, mini-turbines with mini-bliscs with mini-blades? Regular blades have something 0.1-0.2 mm, AFAIK. Mini-s will need something 10 times thinner.

DfAM covers a huge range of topics, enough to do a whole degree on. I'm struggling to find an open-access source for you but the wikipedia entry gives a good basis (https://en.wikipedia.org/wiki/Design_for_Additive_Manufacturing).
For mini-turbines, it is likely you would keep combustion temperatures low enough to prevent the need for excessive cooling channels (i.e. well within the material's operating temperature). Increasing temperature is chasing better efficiency, this is something you would probably need to sacrifice.

Is it possible to order manufacturing of custom part (in fact, a turbine blisk or blades) from Siemens or other sound company?

Where can one study to graduate in AM field? How long would it take for a person with non-engineering degree? What professions there are?

This depends primarily on economics and on desired lifetime.  Rather obviously you need a material whose strengths and melting points exceed the operational specs.  Determining the various break strengths (shear, bending, etc) is an engineering problem, not a manufacturing problem per se.
Next, consider the production time and cost of 3D-printing vs. some typical assembly line process.  Nearly always the 3D approach loses for large quantity builds.
Designing and operating devices like this can be extremely dangerous. Very tight tolerances are required.  This site describes the difficulties, starting with material choice, moving on to tolerances, and so on.  I don't think you want to go at this in your basement.

I would think it's definitely possible, steel 3D printers are most likely capable of printing with the kind of precision you need (I've had experience designing and printing barrels for handguns as part of a forensic science research project), but be aware that with most processes I'm aware of, you'll need to go in post-production and do some polishing or surface refinement, specially for a turbine application where those temperatures are already high and any surface flaws won't help durability.
Otherwise, I would just make sure you use a material with a track record of meeting your specifications. Likely easier finding extremely reliable and robust materials to mill but 3D printing would be possible in theory.
Financially speaking, though I don't have any experience comparing the costs on that specific kind of a component, milling is likely going to be cheaper as long as you can find someone who will do single unit production runs.
Personal opinion: I would go with milling. I've had a lot of experience with 3D printing and am a die-hard proponent of its merits, but given the lack of personal knowledge about how a 3D printed turbine would perform long-run, and the consequences of failure of something rotating at those speeds, I would be inclined to go the traditional manufacturing route.

I don't know, but I suspect that the only justification for commercial 3D printing of this sort of structure is to achieve internal details - for ventilation/cooling, and the level of precision in the process control makes small quantities impractical.

Some companies are already on the move with this idea. I think I remember hearing that Pratt and Whitney and Boeing are 3D printing some of the smaller air foils.
The advantages being that they can achieve manufacturing of more complex, more efficient parts without the hassle of quality control, expensive fixturing/maintenance, and less hands on their proprietary parts and processes.
Most often, a metal alloy part is "printed" using SLA or SLS (commonly), but it's more or less just bonded. Bonding is either done via laser sintering or some form of epoxy for these types of printing processes. The part is pretty much useless for aerospace purposes at this point because you can just break it apart with your hands, as it is very brittle.
Once the metal is bonded in the desired shape, it goes in a furnace to either solidify the sintered material or the epoxy is replaced with another metal such as bronze or nickel. Also during this operation, the part is heat treated to receive the desired material structure. The changes to the material during this process can help set its strength and heat resistance.
A quick Google search on "Inconel 3D Printing" yields a couple companies that can 3D print "exotic" metals such as titanium and inconel. Chances are if a 3D printer can process inconel, it can print most other aerospace materials.
3D printing exotic materials, at this point, is really just gluing sand and baking it in the oven.

Thank you for the answer. The problem making mini blisks is that you can not make any air passages for air cooling, as it requires separate blade production, and even so, it is very difficult to produce such a blades in mini-size. Without cooled blades you can not overcome some efficiency treshold. The second part of my question was if any gas (gas, not steam!) turbines are made of titanium alloys. Do you know something about it?

I'm sorry, I do not personally know on that topic. I'm sure there are some titanium alloys out there, but material science is growing so rapidly now that it's hard to keep track of what materials are being used where now. If I find anything I'll let you know though.


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Missing top layers in Cura
I've just tried to make some small labels with embossed lettering. Base is 1.5 mm, with letters and a perimeter protruding by another 1 mm. After printing, I realised that Cura is not giving me a top layer, all I get is an inner and outer wall for the perimeter and the lettering:

The base is OK, with 4 layers, but there is no infill at the top. Presumably there is a setting that I've missed (I can appreciate that maybe this is a detail to the slicing which is model dependant). Layers are 0.2 mm, top and bottom set to 4 layers.
I had walls set to 1.6 mm, (4 layers) and the wall features here are 1 mm (i.e. 2.5x the nozzle). The features are solid so far as I know, not drawn as a hollow.
I found a relevant bug for Cura: https://github.com/Ultimaker/Cura/issues/1303 (and I also understand a workaround now, just need to write up an answer).

Did you activate "vase mode" or something similar?

Not seen any options looking like that. Other prints are OK, it's just narrow walls.

What is happening here is that Cura is struggling with the quantised extrusion width. This behaviour can be improved in the slicer, they have a issue tracked here https://github.com/Ultimaker/Cura/issues/1303 and 2.4 beta has improved it.
There are some pictures in this answer which show how Cura 2.3 slices a rectangle of increasing width. I got nothing at the nozzle width, then a pair of overlapping lines up to twice the width (which I assume will be over-extruded due to the overlap). For anything wider than simply two sides, the result depends on the number of walls requested.

One wall results in 100% infill for small regions (regardless of the infill setting). This is good, but maybe 1 wall is not apropriate for the whole model.
Multiple walls seem to prevent the infill untill there is space for pairs of walls. So width of 3x nozzle has a gap. Small tweeks to the nozzle size can maybe push this quantisation point about, if 1 wall is not a good workaround.

For rectangular geometry, it's worth trying to quantize small parts in 0.8mm increments. For curves, setting 1 wall shell might be better.

What is your source model?  Typically this "missing layer" effect happens if the source has a wall thickness less than the size of the extruder nozzle selected. Cura will view that part of the model as non-printable.
Meshmixer and TinkerCad (among many others) will allow you to set and change thicknesses in the model.

It came from TinkerCad, its just solid letters, and a solid base with a cutout (to get the perimeter wall). So I'm expecting a wall thickness of 1mm (and a 0.4mm nozzle). So, yes, I guess the question is if I want 0.8mm+0.2mm void, or a 50% over-filled centre.

Try Cura 2.4.0-beta2: there is option named "Fill Gaps Between Walls" under "Shell" settings, set it to "everywhere". In  stable Cura 2.3.1 this option is missing.

Yes, I already noted that 2.4 beta gives some improvements in my answer...


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Has anyone experienced scorching or burning of cork heatbed insulation?
A comment to my question How much insulation do I really need? has made me paranoid about using cork as a heatbed insulator:

Why worry -- other than the fact that it's flammable. All that's needed to start a fire is having the thermistor fail or come loose. I'd use a flameproof material if you're going to insulate.

The flash point (ignition temperature) of cork is, apparently, 300 - 320°C1, which is not, as far as I can tell, a temperature that the heatbed reaches, so, in theory, cork should be safe to use as an insulator. In fact temperatures of around 300C are used in the manufacturing process of some cork products2:

For insulation applications, agglomerates of granules of
  cork, known as black agglomerates, are employed. They
  are manufactured in a closed autoclave at high
  temperature (approximately 300uC) and pressure
  (around 40 kPa) without the use of adhesive

In addtion, according to Why should we use cork?

Does cork burn?
Cork is a slow combustion material. That is to say, yes it burns but very slowly and it doesn't produce flame so it doesn't spread. Also, when burning, the smoke that it releases is not toxic.

However, I am not sure if all cork is equal, or whether the thickness of the cork can affect the safety. To give a definite figure, I was thinking of using 2 mm - 5 mm thick cork sheeting.
Has anyone experienced, or know of, any burning (or scorching) of cork, when used as a backing insulator to a heatbed, in particular, an aluminium PCB MK3 heatbed?

1 Source: What is the the ignition temperature of cork? | ChaCha
2 Source: Cork: properties, capabilities and applications

The thickness of the cork shoudn't affect its combustion. Thicker insulation just means a lower external surface temperature (since the bed temperature is limited by software), and reduced heat flux through the insulator. Bonding materials and glues are probably more significant when you're using some sort of composite material - depending where you source the cork from, it might not be just cork.

The real fire risks with 3d printers are electrical in nature. Lets say your wires come undone and happen to come next to the other lead. If it archs and happened to be in just the right position. Pretty unlikely. Once I did a bad solder job and when I was working on my printer. The wires literally burst into flame in my lap. No damage done (other than needing a new board). That said we often see people who have their boards catch fire in the flashforge owner groups. Weak solder joints, and over all bad quality.
Do you really have something to worry about with Cork? No. A series of unfortunate events would have to happen, and more likely your board will cause a fire. That said I would look into adding a layer of aluminum and reflect some of that heat back up.
If you are that worried I would just remove the sheet. Unless you are having issues calibrating you heated build plate / PIDs there is no reason to use insulation. I only use it on printers that have a hard time hitting ABS temps of 100c. Even then I only use tin foil and try to trap the air underneath.
Just a side note. If you are having heated build plate issues maybe what you really need is a heat chamber.

The cork itself might not cause a fire, but it might be excellent fuel. Just about any consumer item (whether it be a toaster or a couch) is made with flame-retardant materials, and for good reason.

@TomvanderZanden that is a very good point. Maybe those harmless blown up controller boards I see on flashforges would instead result in a burned down apartment complex instead if they used wood. I will note that my first printer used laser cut wood. A lot of these plastic frames we see could also catch.


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What are the advantages of upgrading to a 32 bit microcontroller?
I returned my 3D printer controller board since it died, after only doing a dozen failed/successful prints.
I have bought myself a RADDS board which set me back £72 including motor drivers but not the Arduino Due.
Will I see some real benefit in upgrading to 32 bit because surely it doesn't make it print faster?


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Troubleshooting filament slip on MakerBot 5
I run a high school 3D printer lab and we have several 5th generation MakerBot printers. On one of them I have considerable trouble with "thin" prints and filament slip warnings.
So far I've tried changing extruders and using different filament rolls with no luck. But, if I move the job and the extruder to a different printer it works.
I'd appreciate suggestions for how to sort this out. I would have expected the slipping problems to follow the extruder.

Do you have the Smart Extruder+ installed or still the original Smart Extruder? Also, what are your target parameters such as Layer Height, Infill %, Shell, etc.?

Not at school today, so some of this if from memory. All of the failures were with the original Smart Extruder. Parameters that I remember are: layer height = 0.2mm, infill = 10%, shells = 2, rafts = on.

Oh interesting. By slips, I take it you mean that the raw filament slips, not the print slips.
This will happen for a few reasons. First the tooth gear that grabs the plastic is either:

Worn out
Out of place
Not the correct distance from the guide wheel.

This is all part of the mechanism that the Smart Extruder attaches TO. Not the Smart Extruder itself. You might be able to fix this yourself, worst case you will need a replacement assembly from MakerBot. I would look into online auction sites for the part
Another option is to try thicker filament. Which you might be able to custom order. So instead of 1.5, maybe get 1.8. I am not sure where you can buy off sizes.
From there this machine might just be getting jammed. It happens to some machines. This again points to the base of the X axis assembly.
Last which I would say is not likely as you have tried multiple extruders, you might have the nozzle becoming clogged. I often pop open my extruders voids warranty and clean them out. Also micro hand drills are a good option here.

"This is all part of the mechanism that the Smart Extruder attaches TO" I don't think this is true. I have a Replicator+ extruder which based on YT videos looks very similar. The tooth gear is embedded inside the extruder and mechanically driven by the printer.

I posted an edit to the top answer in hopes that it will get changed for anyone looking at this post in the future but in case it gets rejected here is the actual issue and fix.
If you just want the solution skip down to the bolded text.
I came across this post while browsing for resources to document my own experiences with "filament slip" in Makerbots and every suggested solution was wrong and potentially malicious to the machine. I'm an expert in the field and have taken apart and fixed dozens of machines.
First a bit about the anatomy of the extruder so you can understand better. The way that the toolhead detects slips is with an encoder wheel placed above the actual drive mechanism, not attached to it or the idler whatsoever. It's also not even tensioned against the filament at all. The filament is "held" in place with an injection molded piece of plastic that attaches to the rest of the extruder body just by the pin connectors on the internal PCB and a small positioning groove on both sides of the case.
The encoder wheel and its sensor are very unlikely to wear but what happens to every older head is that either the casing or the injection molded part that holds the filament wears and the encoder wheel no longer presses firmly against the filament which causes the filament to move without turning the encoder. The encoder then not moving while the drive gear is, reads a filament slip and sends an error message even though nothing is mechanically or functionally wrong. The wear is also not clearly visible even on close inspection. This problem seems to arise in every Smart Extruder+ once it reaches 150-200 printing hours.
Actual Fix
As a temporary fix you can jam a piece of foam inside the right side of the extruder to push the poorly secured injection molded part against the encoder wheel. This will make the filament slip error much less frequent but won't completely solve the issue. I'm working on a 3D printed insert that should hold the part more securely, at least until the printed part wears after an additional 100 or so printing hours. I'm also working on a 3D printed replacement for the extruder body and some of the injection molded interior parts. It aims to be a drop in replacement which should greatly improve both reliability and functionality. If I can remember once I'm finished I'll come back and post a link here.

Hi Adam and welcome to SE.3D Printing! I would like to kindly ask you, please do not add additional information to someone else's answer. If you have something to add, please post your own answer (referring back to the answer that you wish to ameliorate, if need be, using the URL of the answer). Your suggested edit, while it may have been correct, was rather confusing, and caused some flags to be raised. Thank you for posting your own answer here... :-) If you wish to edit someone else's answer to correct typos, grammar, fix units, links, or incorrect formatting, please feel free to do so.

This was the cause in my case. I have my filament roll on the side and at just the right angle, the filament would bent slightly away from the wheel, losing contact. A bit of paper jammed behind the injection molded part solved the issue.

Okay, the original Smart Extruder has many issues. I've clocked about 60 hours on a new Replicator+ w/ Smart Extruder+ and haven't encountered any of the issues I heard about with the original extruder. So, I might begin by re-recommending what MakerBot Industries has recommended to their customers which is upgrade your Smart Extruder to the new Smart Extruder+.
However, the extruder may not be completely at fault. A picture says a thousand words, so if you have one, please add one. Based on your description of the part's layers "thinning out", double check your extrusion settings in MakerBot Desktop.
Another potential issue is too much tension on the filament as it is being fed into the extruder. Here are some things that can lead to too much tension:

Filament wound around spool/spool holder
Filament kinked
Too much friction between the spool and spool holder
Too much friction between the filament and the filament guide (the plastic tube)

Finally, and my reason for bringing up the Smart Extruder, is that your extruder may be clogged or "gumming up". In the past, if there was too much tension on the filament and the drive gear was not adjusted correctly, the drive gear would grind the filament. This would lead to small deposits of filament gumming up the drive gear, eventually leading to the filament slipping. Once the filament began slipping, it would slowly no longer extrude and heat up further up the extruder assembly. This inevitably leads to the extruder becoming clogged. In short:

{Too much filament tension} + {Too tight drive gear} = Gumming
{Too much gumming} + Time = Slipping/"Thinning"
{Too much slipping} + time + heat = Clogging

You could also try printing at a higher temperature.  Slips can happen when the filament is not melting and thus not pushing through the extruder consistently.
E.g. I had a spool of PLA filament that would slip constantly at 190°C.  I tried 220°C and then it printed smoothly after that.

I had the same issue, but my solution was a little different. Following along with what the others posted about the wheel, I had a jam inside the extruder around that wheel. I missed it the first time I tore it open so no matter how many times I tried the screwdriver trick it didn't work for me.
I figured I'd post so if anyone is coming along trying to find the solution, they can see that it might be a jam on the filament wheel and not just to check the nozzle area.

We had a similar issue with our Makerbot printer here in the CARIS lab.
We would have slip, after slip and tried oiling, hand feeding, and roughing up the filament none of it worked. But we found an answer!!!
With the smart extruder, it's as simple as inserting a flathead screwdriver between the filament wheel and the housing, and prying the wheel towards the pin-side of the print head. Solved all our problems! Seriously, not a slip since and perfect prints.
I've a short solution video for YouTube, Fixing filament slip on your 3D printer.
Check out the makerbot trouble shooting page for reference: MakerBot Support > Troubleshooting > MakerBot Replicator > Error Codes
ERROR 81

So I had this issue for months, was about to either give up and call my printer a paper weight, but I figured it out. And it doesn't cost anything.
I literally reprinted the same hose adapter 6 times (every time the filament slipped about 20 times and it was unusable). I changed 4 settings and since then I've printed the same print twice in a row without a single filament slip.
In "Device Settings" in Makerbot application:
Extruder Temp: 220 °C
Travel Speed (I think this is what is actually causing the slip): 115 mm/s
Then in the "Infill" section:
Infill Density: 30 %
Lastly in "Model Properties":
Shell Starting Point: 220 °C
Please let me know if this works for you as well.
(I should point out I just have the regular smart extruder, and I was planning on dumping the $350 for the top of the line model)

I use the "MakerBot Desktop" application, as opposed to the new application, because it won't work, so let me know if I need to modify based on application


text:
Change 1.75 mm 3D printer to 3.0 mm printer
I am planning on buying a cheap 3D printer to get into 3D printing, but the printer I'm planning to buy only takes 1.75 mm filament, I was wondering if it might be possible to change the hotend of that printer or something to take in 3.0 mm filament, the reason I want to use 3.0 mm filament is because it is cheaper than 1.75 mm filament.

First it really depends on your printer / extruder. That said generally 1.75 mm is cheaper and much more common.
If one were to change the hotend, likely you will need to replace most or all of the hot end. In the case of my personal hot ends, when I did this conversion I had to replace both the tube and the PETF lined mouth. I did not have to replace the tip, core, or the thermsister.
My advice is to pick a different printer. You see 3 mm on older extruders like J Head direct gear from around 2012-2013 and Bowden style (like the Ultimaker) use 3 mm (actually 2.85 mm).
Possible yes, advised, no.

I would expect the conversion to cost more than you would realistically save on filament.

All depends how much you print

It can be quite straightforward to convert from 1.75 mm to 2.85 or 3.0 mm, but it requires to buy hardware specifically for larger diameter filament. Nowadays, in 2020, Ultimaker is still using 2.85 mm filament which is not more expensive than the smaller diameter (at least not for the premium brands I'm using). I converted to the larger diameter filament years ago to be able to exchange filament with an Ultimaker 3E I maintain and manage.
To convert to a larger diameter, you need to be aware of

the pros and cons of the various diameters
increasing the stepper motor torque to be able to extrude the filament; larger diameter filament requires much more pressure than smaller diameter filament; the easiest way to do that is reducing the speed (and as such increasing the torque) of the extruder using a belt drive or gear reduction
buying specific parts for your hotend, e.g. heat sink, heat break, etc.
modify the steps per mm for the extruder

Thingiverse has always been a great starting point for me for larger diameter filament extruders; my own custom extruders are based on such designs. It is perfectly possible to convert to a different filament diameter, but, it requires some money, time, elbow grease and engineering from your side.

I had my printer Anycubic-Chiron converted from 1.75 mm filament to 3.00 mm, as it is big enough to handle bigger filament and the printer itself came with two sizes of the heatsink - the other fit to 3.00 mm filament.
In addition, I changed my extruder to a "Bulldog" extruder kit for 1.75 and 3 mm filament plus the PTFE tube and had to change the metal tube (heat break) between the heatsink and the hotend.
However, the conversion failed, the filament gets stuck on multiple points. I found many blogs describing this similar issue. The only possible solution is to increase the heat up to 270 °C at which my printer also fails. As the thickness of 3.00 mm filament prevents the heat to reach the middle of it. That's why it spools on the beginning only of printing then stop. There is no way to continue.
So, the problem is with the hotend, being mostly designed to suit 1.75 mm filament, not the printer itself.

I tried cleaning up your answer, please take a look to see if this is what you intended, if not please [edit]. Thanks!

In addition, I fixed some typos and did a minor re-wording, and improved the readability (I think). I hope that is ok.


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Producing closely fitting parts
I would really like to be able to print moving parts that fit well enough to move without excessive friction, but also aren't excessively loose.  Using an Ultimaker 2, what should be my expectations be, and how would I go about produce well fitting parts?
Using a tool like Openscad to generate parametric parts is really useful because it facilitates the creation of geometrically precise parts such as cogs and drive shafts, which also have precise dimensions.  The problem arises when the parts are printed and joined together.
I recently printed some cogs that were supposed to be able to rotate freely around a shaft, which was also printed.  I made the shaft about 0.1 mm smaller than the center hole of the cog expecting it to be able to rotate freely, however I found that I had to bore out the center hole slightly and sand down the shaft.  I then found that the boring was imprecise and the center of rotation was off center.

Although it is an interesting question it is vague and broad. There are like a dozen of different parameters you should mention. For example what type of motion are you talking about? rotational or linear? what is excessive friction and excessive looseness in your opinion? what material are you using, what is the printing orientation? what are your printing parameters (speed, layer thickness...)? if you really need surface quality then post-processing is unavoidable. you may use acetone smoothing or machining. but as other guys have mentioned try and error is the final solution.

Most machine shops work with a +-.005" (.010" total) general tolerance on metal and you gave less than half of that for a 3D print.  You will have to experiment with your printer to find what it can do but I don't know of any printer (SLA, FFM, etc) that can hold .004" without some type of post processing on the print.

There are a lot of factors to 3D printing parts that work and fit together.
A lot of it will be discovered by trial and error, but let's try to put you on the right path.
First your material is what matters the most. Specifically their coefficient of thermal expansion, i.e. how much can the plastic change when heat is applied. PLA's coefficient is low compared to ABS, for example. Which is why the MakerBot can print without a heated bed, but it cannot print ABS with any success.
Here is a list of coefficient of thermal expansions by material.
What you want to do next is to print out a few test items and see for yourself. Below is an example of reality vs. expectation. As you can see the circle shrinks. It will never expand. So you will always make it bigger than you need. It is also good to note in this example below that the block itself is Larger than expected. The best solution is to not expect high tolerances and build a lot of flex into your designs.

Generally you want the hole size larger. If I wanted a 4 mm minimum hole, then I would likely make it 5+ mm.
The best thing you can do is print out a tray and document how different the sizes are. Also, do the same with a print of various peg sizes. Below is an example of such a tray.

Also, you might want to look into other materials such as Nylon and Carbon fiber.
A great source of more tips. Here is a great tutorial, Designing Mechanical Parts - The Whoosh Machine by shapeways, on designing parts.
A RepRap Wiki article on different lubricants in regards to 3D printers. Most people use silicon lube for parts to my knowledge. Again, it depends on your material.

Images taken from this link, The Innovation Station - Tips for Designing 3D Printed Parts.

I think that you've got the right idea in concept, but benchmarking is typically the best way to prove this out.
You should get in the habit of designing with assembly in mind. This means:

Hole sizes should be larger than intended and/or shafts should be smaller than intended
Scaling does not always solve the issue! Avoid relying on scale tools as it can result in reducing/enlarging features you did not intend to scale
My own experience has shown that a clearance of about 0.005" to 0.010" (~125μm to ~250μm) should be enough. However it may be different for your situation with a different printer, filament, climate, etc.
Also consider material shrinkage from the printing process!

I can't attest to the empirical data laid out in the first answer, but I've had to deal with a lot of components printed in two parts to be connected via design-incorporated channels. I always found that, as a reference, a box of width and length 0.98" will slide securely, but freely, into a square channel of width and length 1".

I'll point out I explicitly state they should try themselves as there is no solid answer given the number of factors. Brand to brand of pla will be radically different. Even color to color of the same brand will be different as the pigments change the chemistry. Then we have printers with Fans. Age of materials. The humidity in the air. Ambient temp. There are just too many factors.

I agree completely and don't dispute that individual trial and error will yield your most reliable result. Different geometries and materials all produce different part-to-part characteristics, I just found that the aforementioned box-to-square-channel connection at the stated tolerances have worked pretty well in past.


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Is a heated bed necessary if printing with PLA?
I'm looking at getting this printer, the da Vinci 1.0w 3D Printer, very soon as my first printer. Since this is an enclosed printer, from what I can tell from the pictures, and given that it is a PLA Printer (I'm assuming that is the filament it prints with), is a heated bed necessary? Especially since this printer doesn't have one? Or should I look at a ABS printer instead?
I plan on printing 1:1 scale props.

@TomvanderZanden the linked question might be tweaked slightly to be specific to the case of having an enclosed printer. Allowing this question to be unique. We can discuss in Chat or Meta, but what do you think?

@tbm0115 This question mentions the printer being enclosed as well - if the question were about an open-framed printer it might not be a duplicate. In any case, I don't think the answer changes significantly.

There is problem with sticking to bed without preheat, PLA is possible to print on Kapton tape with no-heated bed. Or there are other tapes dedicated for printing. da Vinci 1.0w is good for small models with PLA. ABS is not possible with no heated bed.


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OctoPrint mjpg-streamer configuration
I'm running an OctoPi Raspberry Pi installation of OctoPrint, and the webcam images are too bright.
I found some documentation on changing the exposure of mjpg-streamer, see github:foosel/OctoPrint/MJPG Streamer configuration, but I don't understand where, or how, to change these settings.

Can you edit your post to include the links to the documentation in your question?

The commands in your documentation only work with the Raspi camera.  If that's the camera you're using, you can use the tools mentioned from terminal on your Raspberry Pi, or over SSH.
If you don't have SSH setup and are using your Raspberry Pi with a keyboard and mouse, you can access the command line by pressing ctrl+alt+f1 remembering that ctrl+alt+f7 brings back your GUI.
Setting exposure for Raspi camera
First navigate to the folder you installed mjpg-streamer.  If you installed it in your home folder:
cd ~/mjpg-streamer/mjpg-streamer-experimental

Then use the input_raspicam.so utility to set the exposure using whatever preset you'd like.
./input_raspicam.so -ex night

If you don't have a Raspi camera
I'm currently using a Logitech HD Webcam C310 with OctoPrint.  I'm pretty sure setting the exposure for that is a pretty standard operation and you shouldn't need to install anything.  v4l2 (video 4 linux 2) comes installed with Raspian.
To set the exposure for a Logitech camera (possibly others too) first enable manual exposure mode (1 for manual, 0 for auto)
v4l2-ctl -c exposure_auto=1

Then set the exposure value with
v4l2-ctl -c exposure_absolute=100

replacing 100 with whatever value you'd like.  The values start at 1 and have a maximum value of 10,000.
These commands can of course be run over SSH.
You can also run
v4l2-ctl --list-ctrls-menus

to see all the options for your camera.
Here's a screenshot of my ssh session and my OctoPrint interface for context:

v4l2-ctl worked very well with my lifecam studio. With my Flashforge Creator Pro, white_balance_temperature=5000 focus_absolute=29 zoom_absolute=0  sharpness=35 looks pretty good!

authors: ญาณิศา พรายทิพย์