gr5

Were you joking about the print times thing? If you your actual print time is 10 seconds faster than predicted by Cura (which assumes slower Z movement) is that going to be a problem for you? It may seem like 2 or even 10 people on the forums having a problem with the Z is "common" in reality it may be only one person in a thousand. I suspect it's pretty rare. I've used easily 10 different UM2 printers, probably 20, and none of them had Z banding issues.

I don't like your cold pulls/atomic pulls. Can you please do it a few degrees cooler? You want a single piece coming out of the head. Ideally do it with Nylon - if you have any. Nylon is more flexible so you can get a good perfect head shaped pull-out at lower temperatures. Then you can inspect the inside of your nozzle. I think you are probably getting nozzle clogs. But I don't know for sure. I don't know why you are getting so many.

Which firmware version do you have (you can check using the menu system on the printer). heater error (as opposed to error stopped - temp sensor) You get an error if the heater can't move a certain amount in a certain time while driving full power (when it is close to goal temp it typically runs well below full power): Firmware Version 14.09 - does not have the feature 14.12 oct 16, 2014 - feature introduced. 20C in 20 Seconds 14.12.1 dec 15, 2014 - from 20C to 10C (still in 20 seconds) 15.01 jan 14, 2015 - from 20 secs to 30 secs (now 10C in 30 seconds)

The funny thing is when Daid first put in that "heater error" feature people kept complaining about it and then Daid realized he had a 35W heater and that the standard UM2 was 25W, lol. So the PID values might also be geared more towards a 35W heater. Anyway he dialed back the heater error parameters and people (mostly) stopped complaining. I have the feature turned off on my UM2 but the feature is turned on for my UM2go.

Wow. It does dual head or single. It "swings out". It doesn't need any special hardware. Fans just slide in with no screws. Better airflow. What's not to like?

It looks like very-easy-to-clean stringing - not too bad - it's hard to say - this looks much better than the photos from before which looked like a disaster. The walls of the rims look perfect, right? It's hard to tell - when I click on your photo it doesn't zoom in (like some photos do on this forum). What are you printing on? Is it flat? It doesn't look flat. Anyway the bottom layer looks fine so whatever you are printing on I guess it's fine. Or could the parts be wiggling on it? It looks like a paper towel with bumps in it, lol. Better to print on masking tape. Or just glass. So I guess my main question is - are you sure this is bad? Looks like easy to remove stringing.

The next time you get a "blob" please photograph it. If you can't create a blob please do a cold pull as neotko suggests and photograph that also. I never really got this part about the blob until now and this is now my strongest focus of most likely issue. You might need a new teflon coupler - do you have one? the ones from 3dsolex are great as they can handle 255C. Although some of them have a new funnel shape where the bowden goes into the part and if you have one of those it seems unlikely but that might be the problem also.

One more thing - you can get this error if you have a loose/intermittent/ or badly connected heater. This is the least likely situation but check the wiring underneath the printer to be sure.

Oh - you can also get this error at high printing temps - for example Anders disabled this test on his firmware as he prints at 290C I believe and he would get the error all the time if he didn't turn the feature off.

This is a very specific error that didn't exist a few firmware versions ago. You get an error if the heater can't move a certain amount in a certain time while driving full power (when it is close to goal temp it typically runs well below full power): Firmware Version 14.09 - does not have the feature 14.12 oct 16, 2014 - feature introduced. 20C in 20 Seconds 14.12.1 dec 15, 2014 - from 20C to 10C (still in 20 seconds) 15.01 jan 14, 2015 - from 20 secs to 30 secs (now 10C in 30 seconds) There's lots of possible causes - the most common is that the block is touching the metal fan shroud. This is PARTICULARLY common with olsson blocks as they are larger - do you have an olsson block by any chance? It can happen also if the fans come on to full power suddenly - normally you want them to come on a little ata time and that's the default for cura. It can happen if your heater is only 20W instead of 25W (this is more common than you would think as they vary by quite a bit). It can happen if you pour water on the nozzle. Or cool it in any other way. Did you get an old printer with the 14.12 version firmware maybe? Check what version firmware you have.

I don't know the answer but it doesn't sound serious to me. You can buy various knobbed sleeves for just a few pounds. google "reprap mk8"

Your question is not clear. Cool head lift leaves little strings but they are very easy to clean up. Usually. This is for very very skinny things like the antennas on the top of the robot. Alternatively you can print a tower next to the robot which results in a beautiful print - it makes a huge difference. It does seem a waste but we are talking about very small amount of money. Ideally place the tower such that you get good fan blowing on your "antenna" or whatever it is that prints in less than 5 seconds per layer.

They might not be cooperative the first time but just keep bugging them. Eventually they should realize the screwed up.

I did some experiments with the pulling force of the extruder at different currents. For some reason the extruder initially got stronger as I increased the current but soon after it got weaker. I believe 1250ma is the default. 1300 is stronger. 1350 is getting weaker again. Don't know why. Also the higher stress on the pcb driver means the extruder driver may shut of power briefly and it can spin backwards from pressure. Also the motor itself can get hotter and melt/soften the PLA such that it grinds up the filament.

yes. I did some research. The slowness has to do with keystrokes so if you paste in the text it's fine. Chrome is allocating about 1mb memory per keystroke - when you get to 1gb (a typical post) chrome will crash. I will be pasting my messages from now on until the forum is fixed.

labern, why removing covers? Well look to me there are 2 classes of problems - one class is the nozzle gets stuck first - dozens of possible causes. The other is the filament grinds first - dozens of possible causes. If the nozzle gets stuck first you expect nothing coming out but filament not yet completely ground to dust for maybe 30 seconds. Also if you try to feed in more filament it won't go. This can be things like nozzle clogs or fractured brittle filament (lately TONS of people ahve had trouble with UM brand filament - you didn't ask about that - where it cracks in the bowden and gets stuck trying to get into the white teflon part - it gets stuck at the break/crack in the filament at the white teflon part. clogs can be caused by bits of dust, bits of bowden, bits of nylon, b its of the nylon black feeder (although you have roberti version) or any other "dust". ABS dust also. or abs strings. Now on the other hand it could be grinding due to too much pressure. The pressures can be amazing - the f;eeder is very strong.. You would expect after grinding you can push in more filament and itextrudes fine as the symptom is ground filament but the cause was too much pressure or too many retractions. This stupid editor has my typing 2 sentences ahead! I hat the new forum edtor! the delay is extreme. i can't see what I'm typing. You need to figure out which class of problems you have.

That wobbly Z looks fine in the first video. In the second video i don't see the Z movement change for the "bad" layer but's really hard to tell even stepping single frames. Did you check to see if the Z stage is hitting anything? Particularly the spool holder sticks through the back of the printer and the Z stage sometimes rubs against that. I would send it back to igo3d again or since they didn't find the problem have them just send you completely new Z rods, Z bearings, Z nut, Z screw and Z motor (I don't think they can send you the z screw without sending the motor also).

For example does the "getting stuck" cause the filament to grind, or does it grind first and *then* stop extruding?

@frederiek, I think you should start from the begining and explain the problem - where it happens the most (first layer? any layer?) and other things you may have left out (all filaments have problem, only some). And if your filament cracks/breaks easily in the bowden and other details like how you got it going again - what you tried that didn't work to get it going and what you tried that did work. Also maybe a photo at the feeder. The brand and color of filaments that work and don't work recently. Nozzle size, anything else that probably isn't relevant but might be. Air temp e.g. "house is colder than usual". Dust situation (we just got a cat who rubs face on filemant).

@frederiekpascal informs me he is having ground up filament again. Lets start all over. Does it usually fail on the bottom layer? Can you post speed and temp settings for the bottom layer? Because the bottom layer is soooo thick you have to print slower or hotter. Usually the bottom layer is .3mm thick so you have to print extra slow if you don't want to grind your filament to dust. Max speeds for .3mm layer: 14mm/sec at 200C 20mm/sec at 210C 27mm/sec at 225C 33mm/sec at 240C Look at the pattern on the filament as it passes through the bowden when things are going good and when it is on the "bad" layer where it is about to fail.

When I affixed my pad to the underside of the plate I moved it to the side - left as seen from above - because the nozzle is towards the left of the print head. So the wires avoid the spring by quite a bit.

Actually a thermocouple requries more electronics and can't be measured with the arduino directly so you might want to go with the thermister route - something like the EPCOS mentioned here: http://reprap.org/wiki/Thermistor#EPCOS_100K_Thermistor_.28B57540G0104F000.29

I use DSM also. I was able to create things immediately but it took me a month to be as fast in DSM as I had been in sketchup. It takes a while to learn a new cad system. It takes a long time before you learn all the shortcut keys and memorize ways to rotate and switch modes without thinking about it and understanding all the several dozen ways to take advantage of "pull". The "push/pull" feature in DSM is, well, overwhelming in it's abilities and incredibly useful. And confusing (there's the alt-select blue part and then the shift select orange part and then the modes of pull).

good link. I saved that for future when people have this same issue. I'm going to point IRobertI to this thread and see if he has input on solidWorks as that is what he uses i think.

It really takes hundreds of prints to get extremely good at a technique. I tried kapton on aluminum heated bed for about 20 prints. I would often tear it - didn't do enough prints to get really good at it. I could not get two adjacent strips perfect together and so would get a line on the bottom at the seam. But I was pretty happy with kapton. I've done more than 100 prints on glass with PVA glue and I prefer that. I can use the same glue for about 5 or 10 prints without re-applying. With glue stick the bottom is messy unless you dilute the glue with water and spread it until it's invisible. With hairspray it goes on pefectly thin but you have to waste some tissues to keep hairspray off the printer (spray tissue, spread glue). My favorite is wood glue mixed with 10 parts water, brush it on with paint brush. Dry to invisibility. hairspray, gluestick, wood glue - all are PVA glue.