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Interesting idea. I have no idea. Maybe it could also cause the extruder to slip and therefore grind the filament?

Illuminarti puts his filament on a lazy susan. I tried one from rubbermaid - it has ball bearings - very smooth: http://www.hardwarestore.com/lazy-susan-606736.aspx?utm_source=pla&utm_medium=cpc&utm_term=&utm_campaign=rkg&device=c&network=g&matchtype= The lazy susan rotates as the filament feeds in.

The sound happens even when the x,y steppers have stopped. It happens even during retraction. It can't be belt related because x,y steppers have stopped. I don't think it's Z related. It doesn't sound related to the ultimaker at all.

Aluminum with glass on top. Aluminum is very good at spreading the heat. Glass is very flat and resistant to scratches. There are lots of pictures - I recommend you use images.google.com and search for ultimaker2 bed:

1) Is your third fan working? It should always be on and keeps the region cool that you are discussing. It comes on even before the lights come on. If not it is very easy to fix (usually). 2) Your temp/speed/layer height looks quite reasonable. What is more likely causing this is retraction which raises warmer PLA upwards thus transfering heat upwards. Then it goes back in, heats up PLA higher up, retraction occurs again and heat is transferred still further upwards. Melting temp of PLA is around 170C but the "glass temp" is around 50 or 60C. Above this temp it starts to get soft and stickier and can jam. So reducing from 220 to 210C is not going to make much of a difference compared to the 50-60C needed to cause problems. Having said that, Illuminarti did a 30 or so hour print on a UM2 with over a kilometer of retracions. Yes, that's right. A kilometer! Actually 1.6 kilometers. And he had no problems. 3) Something is wrong with your extruder. It should never grind the filament to dust. It should not have enough power. I think the tension is not strong enough - the tension indicator (the white square) should be at the top but maybe it's a little too loose? Are you aware of how to adjust this? You need to insert an allen wrench or similar into the screw that is accessible from the top. Turn it until the white square starts moving downwards and then back off so that it has moved down only the tiniest amount. 4) Ultimaker sells great PLA but... I recommend trying another spool/color/brand - someone recently had similar problems with a bad batch of PLA (not from ultimaker) and changing filament fixed everything. The grinding *and* the clogging.

Several people had a cold solder joint where the 4 heated bed wires are soldered in. The joint can have a crack so tiny that you can't see it. I recommend heating up all 4 - or at least the 2 big wire ones. See this first: http://umforum.ultimaker.com/index.php?/topic/3735-a-fix-for-ultimaker-2-heated-bed-not-working/ And this photo also: http://umforum.ultimaker.com/index.php?/topic/3636-how-do-i-troubleshootrepair-an-ultimaker-2-error-%E2%80%93-stopped-temp-sensor-bed/?p=28218

It's not skipped steps. If it were skipped steps the affect would continue upwards (it wouldn't recover). No I think the problem is that the friction on the long belt pulleys is so high that when the stepper comes to a stop, there is still a lot of tension on the short belt trying to move the head but the head doesn't move the last .5mm or so. It never occurred to me that you can get play/backlash if the belts are too loose or too tight but now I know.

OH WAIT - there's a new video. I was talking about this older video that ERIK HIMSELF made. The newer video shot vertically with a smart phone doesn't tell me *anything*. It could be amazingly loose and the person is just barely lifting.

Wow. I added "solved" to the topic title. I'm very musical so I listened carefully to the video and the belts are quite loose in that video. They are *barely* tight enough to make an audible note. Mine are pretty loose also. The UM2 however has quite tight belts. Anyway - I really don't see how having "too tight" belts caused this exactly. I guess there was so much friction that the motor would move an additional .3mm but the pulleys (and head) would stop before moving that last little bit? That must be it.

Sometimes people post a link to facebook that points to this forum. Facebook has to scan this forum to locate possible icons to go along with the post. Sometimes facebook includes the title tag in the posting. I'm guessing that is it but I don't know. Also at the bottom of this page is a facebook "like" button. Everytime someone clicks on that, facebook is going to scan this page also and put something on the person's feed possibly. bing and facebook have a partnership (microsoft owns a lot of facebook). I think bing search is hoping (or already does) to use this "like" data as SEO companies create thousands of fake websites every day and the "like" button on this forum can help weed out this kind of thing. If someone else knows more then I'd love to hear it.

I would use "natural" PLA with no colors or dyes or additives. Some dyes are a bit toxic. I would also contact the manufacturer and tell them my plans and ask about possible contaminants. As far as sterilization is concerned, the printing temperature of over 180C is a big plus. Then if you sterilize again after the part is printed I think you won't have to worry about bacteria, viri or fungi. Beware that PLA has a glass temperature of around 50-60C so you can't sterilize it with heat after it has been printed as you don't want to heat it above 50C. You could use alcohol. I agree that there may be unknown chemicals mixed with the PLA but there is a good chance that this is safe. I just wouldn't want to try it on my own pet. Many people touch PLA printed objects with their fingers and then later put their fingers in their mouths. I suspect PLA is relatively safe inside an animal because it breaks down very slowly so any toxins would be released very gradually.

This is minor warping. You can fix it by using 70C bed temp, using brim (you didn't use brim - use brim - it works great) and of course the glue stick. The brim keeps air from getting under the corner of your print - it is important. Once the print starts lifting it is hard to stop. Brim helps this quite a bit. PLA has a melting temperature and a glass temperature. The melting temperature is around 170C. The glass temperature is around 50-60C. When PLA gets above the glass temperature it still holds it's shape but if you push on it, then it will very slowly change shape. Permanently. Keeping the bottom few layers above the glass temperature mean it won't warp and if layers higher up warp it will instead deform a bit but it won't lift off the glass. As for PLAs that don't warp so much: PLA45 (google it). Unfortunately PLA45 only comes in black and white I believe. Also ABS warps much *more* than PLA.

If it's wired up backwards then you can tell because the "loop wire" in my drawing below should normally connect a black wire on one fan to a red on the other but if it's wired wrong it will connect a black to a black or a red to a red:

I just had another thought. Illuminarti mentioned that when he wired up a fan backwards it didn't work (didn't spin). Normally when you wire a dc motor up backwards it spins the other way but not these fans. My theory is that the "green green" connector is wired up backwards so the fan connected there gets power but won't spin.

When speed is 0 they are off. When speed gets above around 30% they start spinning. Between around 10 and 30 percent they need a little push to get going. This is bizarre since they are wired in series. "wired in series" is the same way dual battery flashlights work. If you remove one battery, the circuit is open and the light will not come on. So if you disconnect either fan, both should stop. The obvious conclusion - the only thing I can think of - is that the green-green wires are shorted together. Maybe inside the connector? Or maybe it's just totally wired up wrong. Could you photograph the wiring please? Include the wire that connects the two connectors together.

That version is great and it is relatively new. It has some bugs fixed.

The UM2 prints slower than the UM1 (It can move fast but it extrudes less volume per second). So making the layers thinner or raising the temperature both can potentially help certain issues. I still don't quite understand why a little underextrusion would make this pattern though. Maybe it's something that has nothing to do with underextrusion.

I doubt it's retraction as I believe the speed is capped at 25mm/sec typically - but I haven't looked at Daid's latest build. I bet you are simply printing too cold or too fast. What is your temp, layer height, and print speed? For example 190, .2, 100mm/sec will grind up your filament. But 220, .1, 100mm/sec should be fine. My spring compression amount by the way is 11.5mm and Illuminarti's is 11.0mm. That's with the filament loaded and the clamp closed.

I never seen this before. I've never heard of this before. It sounds like bad filament maybe. Sticky filament? Like gum? Usually the colder you are, the less likely the PLA will come out so usually I recommend colder - maybe 190C. But if you have a .4mm nozzle and are printing .2mm layers, you probably need to print pretty slow - like 30mm/sec.

Most paints will not stick to PLA. But automotive primer will. And any paint should stick to primer.

I think you should show a video of the problem. 1) Does the knurled piece spin or is it tight with the motor now? 2) I see no problem with the other screw - it should be able to control tension. Can you demonstrate the problem as everything sounds great except that your knurled piece seemed to be slipping.

The point of brim - well first you have to understand why PLA and ABS stick to glass. Apparently it is the van-der-wal force or something like that - but it requires that no air get under. The brim isn't so much to hold it down but more to keep the air leaking in. Also how hot was your bed? If you keep the bed above the glass temp of ABS then it can't warp. Typically people keep the bottom 5 or 10mm of the plastic above the glass temp. If it is too warm it will sag. 100C is typical for ABS.

Maybe - it's hard to tell if each line is actually two lines or one. I zoomed in and concluded his backlash is fine but I could be wrong.

As I understand it, sprialize *only* works properly for an object where every slice is a single closed polygon. So this works great for vases and cups. Also it will only do a single pass on this polygon wall so if you ask for a .8mm wide wall and you have a .4mm nozzle it will be basically extruding at 200% flow. Also it will not print a top. The part you show here - if you slice it is more like to curve segments that don't meet. It is nothing like a polygon. Another rule of thumb: spiralize and retraction should never occur on the same part.

I don't get it. Why would you do a material change? Why not just go to the "move material" menu and have the extruder push it back into the print head?