gr5

Um. Yeah. Put the cover back on. You can put washers under the cover before putting screws through it. Or you can print these things: http://www.thingiverse.com/thing:54075

You can try cool head lift also. That works. But I really love printing two. Or putting a tower next to it.

I heard second hand a month or so ago that Erik (a UM founder) is looking into a device that would measure the actual movement of the filament and feed that information back to the Arduino. I don't know how active this experiment is. There are really a bunch of things going on with UM engineering. Definitely! You need to get your damn UM2 so you can start playing with it and not spend all your time on these forums!

Those bracelets are printed every 10 minutes almost exactly at Ultimaker shows. They print on the UM Original at very fast - 150mm/sec? 300mm/sec?

UM1 or UM2? The UM1 has fan only on left side and the nozzle on the UM2 is closer to the left fan. This causes assymetric cooling of the nozzle (you don't want *any* cooling of the nozzle of course) and can mess with the nozzle temperature for a few seconds causing underextrusion on one side. I would expect it worse as the nozzle is more to the right side because the flat surface of the part is under the fan bouncing the air across to the nozzle. The PID adjusts within 30 seconds (which might be too slow) and then it overshoots in temp a bit. The solution is to print 10C hotter. 240C is a safe printing temp. 250C is dangerous. Never leave the machine just sitting there with the temp at 250C or it will cook to a black gunky mess.

I just changed to test. I found higher current means the filament grinds and slips and the print fails which is worse than slipping.

There are many types of nylon so you should specify the seller and brand e.g. taulman 615, pa6. Some are stretchy soft, some are hard like PLA. For the hard pa6 nylon I had to go 250C minimum temp or the layers didn't bond well and the part broke too easily.

Oh - and the side 2 fans dont' come on by default until the 4th layer or so and they gradually get more powerful. Because the nozzle is on the left side of the head the right side gets slightly worse airflow but it should be fine on the UM2 if you lower your bed temp to 70C.

That discussion looks to be mainly for the UM Original but you have the "2", right? Make sure all 3 head fans are working next time you print. The 3rd fan at the back of the print head should come on as soon as you power up the UM, before even the lights. Make sure in your Cura settings and on the UM2 material settings the fans are at 100%. Probably you are printing a bit too hot. The default bed temp for PLA is 75C but that's too hot. 70C works much better. I always print at 70C. Some people swear that 65C is better. Your PLA should be no hotter than 240C. I usually print at 220C for higher quality prints. That's my answer but while here I'll discuss temperature versus speed briefly. The hotter you print the faster you can print because cooler plastic has a higher viscosity (cooler pla is like toothpaste, hotter pla is like honey). So the feeder needs much more energy to get the PLA throught the nozzle at higher speeds or colder temps. So you can't do both. You have a trade off between temperature and speed.

strange.

Acetone vapor does cause the part to lose detail - quite a bit and only works for ABS. If you are only printing 1 model per month I strongly recommend using shapeways.com or similar service. You don't have to worry about support with shapeways as they print in the powder which supports the part until it's done (google SLS 3d printing). Sanding PLA doesn't look good - it loses it's shine/sheen. It gets milky/cloudy instead of shiny. Some say you can put baby oil (or any oil) on it afterwards and then it looks "good as new". For months. I never tried it. Sanding is great if you will then prime it after. Any automobile primer works great on PLA and then you can paint with any kind of paint you want once it has been primed. Or just leave it as is.

Also the underextrusion may have been caused by filament tangling so pay attention to that occasionally.

Those "holes" are underextrusion - I would raise the temp to 240C if you aren't already up there. For this part and other parts I assume you will be painting them anyway so you can simply cut off any strings which you would not get on 90% of this part anyway. So I don't see any reason to go below 240C on this convex part. Other parts will need cooler and slower. Parts with external overhangs.

Just post anything. I am one of about 5 moderators.

I used the needle method where I marked a dot on the needle with permanent marker just below where it disappears into the nozzle and then measured with calpers like the one in the picture above. I got 0.40mm +/- .02mm It wasn't easy - I needed a magnifying glass and I had to make the dot closer and closer until it almost disappeared. It took about 15 minutes.

Makersheds supply of 30 UM2's ran out very fast - about a week. That was back in December. There is a big rumor that they will be getting another shipment soon - in the next few weeks - you will have to act fast - within a few days. I was with UM employees the last 5 days and they didn't confirm or deny the rumor. I wouldn't cancel my order just yet.

Oh! Yes! Genius. It's probably a software endstop. What a stupid feature for the E axis. There are other solutions such as put it in "relative" mode. Can you verify this fix? I'm away from home until late tonight. If you verify it we should alert Daid. This bug has been around for a long time but "one-at-a-time" is not done all that often - probably because of this bug!

I'm only familiar with makerbot and UM. I met many Makerbot and Ultimaker users at the 3dprintshow in NYC last 3 days. The UM users seemed quite happy. The Makerbot users seemed mixed. I met a few who had both and said there is no contest - UM is far superior. But really this is 3rd hand. Even I don't trust the info. Also makerbot had I believe only 1 printer printing and twice the staff at their similar sized booth as Ultimaker. Ultimaker had 10 (TEN) printers printing and it was rare that more than 1 printer was not printing and always because it had finished a print. Why doesn't makerbot have more printers running? Also none of their new models were printing anything.

I changed the name of this topic to mention "feeder" instead of "extruder". It was pointed out to me by 5 people in the last 5 days that the extruder consists of the feeder behind the UM and the head/nozzle. This topic seems mainly to be about the feeder.

Daid? Did you see this? I haven't noticed but I don't change filament very often. Do you have *firmware* version 14.02? It fixes some bugs like this. To reduce even further the chance that you will grind filament. You can change the driver current with a gcode. I posted it somewhere else. I think maybe in "extruder pull test" maybe. I need to rename that to "feeder pull test" which I might do now.

This whole 90% flow thing is very intriguing. It doesn't make sense to me so it is unexpected and interesting and likely important. Usually the 90% extrusion is caused by the filament slipping the tiniest bit as each tooth digs into the filament and it slips a little. So the stepper is turning at the 100% correct value but the filament is moving at 90% of desired value. So the stepper doesn't know the filament is slipping. The whole 90% flow thing is more likely to have something to do with how the filament leaves the nozzle and flows into the corners of the part. With 90% flow it doesn't quite fill a layer completely so there is a tiny space to move into when it is done and there is significantly less pressure. Have any of you tried to increase the current? It is a trivial single gcocde command. I tried it and my filament ground to dust.

We are almost to 25 pages! Aaron - Stepper motors have a natural position. When you push hard enough you can overcome the current holding them in place and they will move (click) suddenly into the next position. I'm not sure if this is 1 or 4 steps (I think 4 steps). This is about 1/8 or a little less of a turn on the extruder. Occasionally the pressure against the filament is so high it will go double this (8 steps). The pressure is indeed mostly in the bowden. These feeders can push about 5Kg which comes out to almost 1000 psi inside the nozzle! Of course it is underextruding slightly (probably about 10% if you look at some of illuminarti's experiments) just before the slip but 10% isn't really very visible. Once it slips back it takes quite a while to recover. This design is on purpose. The slip is not detected - if it were it would try to recover quickly instead of slowly. This design is preferred (by me at least) over grinding the filament into powder. Worse, on the UM1 early design it would break something else - usually popping the bowden tube off and scraping it with the metal blades that hold it in place and ruining it.

Nicolinux, someone else mentioned this nut so I looked at my extruder motor on the inside of the machine and it is flush against the back panel. Please also do this - look straight down from above and make sure the motor is touching nicely. Nicolinux, I hung out with Sander the last 4 days and he said that he thought your part was shipped out about a week ago. He will not be coherent until Tuesday so wait until then to contact him. I think your package must have been sent to the wrong address.

I can't watch the video right now (youtube would be more convenient) but this is a problem I haven't heard of before. The most likely problems seem to be: 1) Too much friction (end caps might be too tight on rods, or belts too tight). Loose belts wouldn't likely cause this - more likely tight belts. 2) Bad power supply. I would recommend attaching a volt meter to the 19V supply and leaving it connected while you control the machine - if voltage drops below 18V there is a problem. 3) Bad stepper drivers - they are replaceable. It seems unlikely that 2 would be broken though. Is the fan working on the bottom of your UM? Does it blow in the right directon? (not suck?)

Good detective work!