gr5

I had the same problem - check the wires to the temp sensor (the thinner two wires). Make sure they are screwed down tight. If they are then you might need to reflow (reheat) the solder. You might violate your warranty if you don't let UM Support know about this first - I think the newer UM2's have a sticker on this connector warning you to contact support first.

I haven't experimented much at all with "glues". I just follow other's advice. glue stick or wood glue mixed with water and painted on work incredibly well for PLA (on rare occasions it sticks so well it removes a tiny sliver of glass!). hairspray or abs juice works very well for ABS. I think you can mix and match these products somewhat but not sure. I did some experiments actually with different temperatures and with the glue stick here: http://umforum.ultimaker.com/index.php?/topic/3404-printing-on-glass/ It was very informative - basically there is a sudden temperature change where it sticks incredibly well above a certain temp and horribly below the temp and it doesn't matter how much above or below the threshold you are.

But noone else is having PID issues and lots of people have upgraded the firmware. Daid didn't mention any changes in the PID values or the PID code so I really doubt it's firmware. Plus this is a somewhat common problem. Every time the print head moves back and forth the wires get stressed a little bit. If the wires short a bit that lowers the resistance which indicates a lower temperature.

I would go log scale. So maybe 50% increments? .4 *1.5 is .6 *1.5 is .9 /1.5 is .26 That would give you .26 .4 .6 .9 1.4 Or maybe 30% increments? .18 .25 .3 .4 .5 .7 .85 1.1 I would pick a ratio (I tried 1.5 and 1.3 - maybe 1.4 is better) and go with that for the nozzle sizes. At some point the wattage of the UM2 heater can't go any faster so there is no need to go above a certain size nozzle hole. Someone with a nozzle larger than mine (I have .7) will have to experiment with max extrusion rates. For my UM2, .7 nozzle can each go up to about 18mm^3/sec. .4 nozzle up to about 7mm^3/sec. At 230C. Someone else reported the same speed with .8mm nozzle. data here (posts #1 dark blue line and post #8) http://umforum.ultimaker.com/index.php?/topic/4127-um2-extrusion-rates-revisited/

Do you have UM Original? Or UM2? On the UM Original it's easy. You can get nozzles on ebay - very inexpensive - cost of cup of coffee. Then you heat the nozzle to 180C before unscrewing old one and adding new nozzle. On the UM2 it is very difficult because the nozzle is so complicated - it has the heater inside the nozzle. Best thing to do is order a second nozzle (about 50 euros), then find someone with a machine shop who can fill in the existing hole with brass solder and then redrill out the hole. This is a very delicate operation. .25mm drills are extremely delicate. So you need precision equipment (drill press or lathe). It takes 1 minute to change the nozzle on UM Original. 30 minutes on UM2. Someone here in the USA is planning on redesigning the nozzle so that it is in two parts and selling different size nozzles. This has not happened yet. Here is his post - maybe you should contact him: http://umforum.ultimaker.com/index.php?/topic/6622-making-different-nozzle-sizes/

Make your supports larger in diameter - it's a setting in meshmixer. Make sure fan is 100% by 1mm (as soon as you have any overhangs). Add one more support lower down to help that big tube hold still sooner.

For your worst surface - it is almost horizontal - I can't get any better than this. The most important thing is lots of fan but I suspect you already have your fans on at 100%. Print speed won't make a difference unless you go to 5mm/sec with .8mm shell because when it does the second inner pass it fixes the outer edge (remelts it). But any faster than 5mm and it is no help. There is more information about this here (note that the first few theories were wrong but we eventually figured it out): http://umforum.ultimaker.com/index.php?/topic/4094-raised-edges/ Hopefully someone on this forum will become an expert at second extruder support materials and we can some day print this part perfectly. Or just try 5mm/sec. I dont have the patience to print that slow.

You can read off the XY acceleration using the controls on the front of the printer (maintenance, advanced, motion control).

Well I looked at the above gcode in repetier host carefully and also in cura carefully and loaded the settings and looked at that also. Those sides are printed in a single pass which is good (a single line) yet they seem to show some kind of pattern that shouldn't be there. The only theory I have right now - and I like this theory - is that your XY acceleration is different on the 2 versions of firmware. With the lower acceleration giving the higher quality results. It would be nice to see the photos and the gcode file that match each other however. Another theory has to do with the travel speed and infill pattern but I don't want to repeat that theory without seeing matching files so I can match up the infill to the visible pattern in the photo.

That doesn't match the photo. It's the wrong gcode file. Why make us to 3 times the work if you want help. I suggest if you ask someone to do something you do a little work yourself. If this is the gcode with the worst quality difference then maybe post the pictures of this part.

Oh and bottom layer should be .3mm thick - that's the default in Cura.

So probably you need to move the nozzle and bed closer together. I don't recommend re-levelling - just turn all 3 screws counter clockwise (looking from below) to raise the glass plate slightly. Maybe 1/4 turn and if the gaps aren't gone turn it a little more while it's printing the brim. Also more brim might help I think 10 passes/loops is usually enough but strange enough - 20 is better than 10.

Try 240C. 260C seems much too hot - ABS is even worse than PLA at turning into a brown crud at higher temperatures. You probably need to clean your nozzle at this point. Try the cold pull/ atomic method at 140C but I suspect you need to take the nozzle out and clean it now. Also don't let the ABS stay that hot (240C) without printing. I actually print ABS at 245C. Bed should be at 110C.

Was the brim squished a bit into the glass? It should be and there should not be gaps between the brim lines. Instead of the glue which works, it's better to use either hairspray or abs juice (google abs juice). Make sure you clean the glass well before switching glue type. I use this type (blue - unscented) as my wife also uses it to remove stains when doing laundry:

The 3rd fan (rear fan) is always on and keeps the UPPER part of the print head cool. If this doesn't work you can get filament jams because the filament is too soft. Cura controls only the side 2 fans. The temperature is only controlled through heating element and temperature sensor both are inside the print head. You probably have a bad connection on the temperature sensor. It's important to fix this because if the head is at 210C but the temp sensor says it is at 150C then it will keep heating and you can damage things. Like Johnny says - probably a bad connection in the sensor wiring somewhere. With everything at room temperature I would look at the temperature reading and then poke on every possible part of the sensor wire hoping the temperature will jump/change suddenly. Remove larger bottom cover and check connection there also. But the most likely place for the problem is inside the nozzle or just outside so you might need to take the head apart.

This is normal. It happens when the pressure in the print head is too high and the force to push on the filament exceeds about 5Kg. What is happening at the nozzle during this time? Perhaps you are printing the first layer and the nozzle is too close to the bed and there is no room for the filament to come out? Or maybe the nozzle is clogged? Or the filament is stuck on something inside the print head?

Or "emergency need to unclog nozzle and continue" kind of pause. It's not good that it hits the other part on the bed.

The teflon does better if you keep the temperature lower and don't tighten the nozzle too high up (the nozzle position is adjustable so that you can make both nozzles the same height easily - if dual extrusion ever becomes available). I'm not sure which is more important, having the nozzle down low or keeping the temperature low. I think 250C is a bit hot for that part so keeping your printing at 220C might improve the teflon piece lifetime. Or maybe failure is inevitable.

You have to loosen I believe 2 of the long belt pulleys. For example the top 2 in your photo (the rear two for the rear X axis belt - then slide the top and bottom blocks all the way to the left, verify the 2 distances are now equal and retighten the long belt pulley set screws. Very very tight. Repeat for Y axis if not already perfect.

If someone only wants to have to print 2 parts (once with each version) which single gcode file is the best to test with?

Not sure except they aren't as experienced with ABS as their first printer didn't have a heated bed so ABS is kind of new for them. I mean many of the employees print ABS likely but mostly it's been PLA. Daid probably did some research but got some bad answers. Not sure. Or maybe 260 is usually fine but I doubt it.

This is very interesting and very strange. Maybe they were printed at different temperatures?

The moire pattern is bizarre. I'd have to see the STL file. Maybe that "flat" side isn't made up of 2 triangles but instead thousands?

I think the leveling procedure, with practice can get the bed level to about .03mm but you are demanding higher quality on the first layer than anyone I have seen before. I have only gotten that kind of quality once - when I was making an airplane (that actually flies). On that part I did .1mm bottom layer and there are no seams at all. So I recommend you stop using the normal leveling procedure. I haven't leveled in over a month because once you get it right it tends to stay perfect for a long time. Also leveling will change when you heat the bed and nozzle because heat causes things to expand and changes the level point. So why not print just the skirt only and adjust while printing the skirt? You can print it very slow and cancel the print once the skirt finishes and repeat until you get it perfect. You want the second pass of the skirt to just barely touch the first pass of the skirt when you peel it up and look at the underside - you want all gaps/cracks to be invisible/gone. This method is more accurate than the normal procedure and you should be able to get it down to about .01mm (10X thinner than a .1mm layer of filament). Especially if you only care about the very center of your print area because you are printing a small knob. Yes, that's what I meant. Or alternatively you could just move the glass a little closer. As long as you have gaps between the lines (as I saw in your photo) you can only remove those by getting the nozzle and glass a wee bit closer.

Try robert's suggestsions first. Especially the 3rd fan! I wish you showed a photo of the *other* side of the white teflon part. It's the other side that tends to go bad - the hot side. Also try pushing some virgin filament through the coupling to feel if there is friction. If so you might want to drill it out (3mm drill bit). But I'm thinking your 3rd fan broke. The wiring breaks easily - especially under the black mesh covering just at the top of the print head.