gr5

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.

I was at 5.5mm retraction for a while until I seated my bowden more firmly - it used to go up and down with each retraction. Now that it's firmly tight I am happier at 4.5mm retraction. If you retract too much air will get into the nozzle. Which is bad. Regarding seams and bumps. You can reduce these by printing slower. I find 35mm/sec is slow enough for excellent quality or 20mm/sec for best possible quality. This results in a constant extrusion speed around corners and such which helps greatly to eliminate under and over extrusion on slow down/speed up. 35mm/sec should eliminate your Z seam. I've never had to use the Z hop. It's really more for delta printers I think where all 3 steppers are moving on every move anyway. You can also reduce your Z seam by increasing Z axis acceleration. I have only messed with this on the UM Original but was able to get my Z movement from a brief sound to a click it's now so fast. Just by doubling the acceleration (didn't touch Z velocity). I haven't messed with Z acceleration on my UM2 but it sounds much slower than my UM Original so I suspect you can safely double it.

Also I printed with fan at 0% for entire print. This is recommended for ABS to get good layer adhesion/bonding. Most of the many differences between ABS and PLA have to do simply with their different glass transition. But this fan thing may be relevant as blowing air on the nozzle cools it for a bit until PID eventually compensates.

1) I haven't had problems with ABS but I'm less experienced with it so I was very careful about the temperature. ABS can bake into a clog much more easily than PLA. So what was your nozzle temp? I have been using only 245C as I'm afraid to do any other temp. Also you should not let the nozzle stay at that temp ever without extruding (e.g. during bed warmup) so I always warm the bed first. My bed was at 110C I believe (I can check my notes if you want). I think that's the most important thing. 2) If the filament reaches 3.01mm then you have a problem. I would test it with calipers. If you don't have metric calipers I recommend you get some. They are an extremely useful tool and practically required for 3d printing and especially for doing CAD. 3) I am also in USA and got my ABS here: ultimachine.com

If you like the quality at lower print speeds versus 100mm/sec then maybe you should print the entire part at the lower print speed. If you only want to improve quality on the top portion of the part then consider using "TweakAtZ" which allows you to slow down the speed at a given layer height (Z). The "minimal layer time" feature is only to improve *cooling*.

I haven't used the new cura print window so thanks for clarifying. duty cycle/percentage power applied = pconst*P+iconst*I+dconst*D Where P,I,D are the current error, integral (sum) of all past error and derivative (slope or rate of change) of error respectively. So definitely reducing all 3 by power capability is a good first guess. Oh and error is (goal temp - current temp). But, yes, it's true that it matters how long it takes for a change in power to reflect in the sensor readings. This delay is very important for setting D setting particularly but also P and I. They are all interrelated - it's hard to adjust one parameter without messing up the other 2. In general if you are overshooting, reduce P or I or increase D. I'm told E3D tends to overshoot/oscillate massively. Also you might have to reduce the "max power" setting but that requires a firmware change. This has helped other's in the past. Because by the time the PID feature kicks in often it's already too late - it's going to overshoot (I don't understand why PID only kicks in within 10 or 20C of the goal temp - this seems wrong).

If you do use pronterface it will tell you the current PID values when you connect to the printer and you can see the results after tuning. And I think after doing autotune you still have to issue another command to save the values. Maybe. So doing it through pronterface might be better than cura print window (not sure). Also through pronterface you can then power cycle the printer and see if the PID values were changed properly. pronterface is here: http://koti.kapsi.fi/~kliment/printrun/

Many people have had trouble tuning other hot ends. You might want to learn the wattage of the UM2 hot end versus the E3D and scale all the values accordingly. For example if your hotend is double the wattage (at 19V) then cut all 3 PID values by half. Also PID doesn't kick in until around 10 or 20C from the goal voltage. Some people had better luck tuning if they started with a higher temperature when they started tuning. Or tuning to a lower temperature (because it can error out if it gets over 250C). I don't know if that makes sense. There is a fantastic article on PID, how it works and how to do manual tuning on wikipedia.

I would also love this feature.

The printer prints pretty much identically whether it is upside-down or on it's side or whatever. The oozing will not stop - it is created by expansion due to heating. Cold(er) filament is always entering the nozzle. If you stop extruding the heat moves up a bit. More filament heats, more filament expands.

That's a very common problem - as robert said - lower bed temperature.

Also in quality mode it would do all islands clockwise instead of doing the next layer up anti-clockwise and retracing over hot PLA.

The problem with that is if it sits there for a whole second then it will start to ooze and that string will then get joined/welded back onto the part. The 2 tower method works great however. I want a cura feature such that you can choose quality versus speed Z moves. In speed mode it does the z move and continues with same part. In quality mode it jumps to a new part after doing the Z move.

Okay - now who is making fun??? I don't have a touch screen. Or a laptop. I get pain in my arms if I use a normal mouse. I can only use track balls. My mouse looks like this:

You will be better off if the filament isn't on a reel. You can put it on a turntable flat on the floor (costs like 5 pounds) or you can build something out of kinex maybe? It's not that bad. I am very jealous that you live in the same country as faberdashery.

I agree. Backlasy aka play. Caused by either friction too high or much more likely belts too loose. Especially the short belts on the motor which are also the easiest to tighten.

You should really start a new topic. Also better to post 3 images instead of 1 album - when you click my media brows images (not galleries). I think you simply need to slide the Z endstop switch. It's in two very long tall grooves so that you can slide the Z endstop switch up or down as needed.

Regarding the internal stringing - that's normal. And from the video I can see that many of the travel moves are right towards the spot where you are underextruding. You can reduce this by keeping the travel speed fast (it's at 150mm/sec right now - you can safely go even faster to 200mm/sec) but more importantly print slower and colder. This way the nozzle will leak less during the travel moves so that there will still be plenty of plastic in the nozzle for the outer shell. Try 25mm/sec print speed and 190C temperature. I'm not sure that will work but I think it will. That's what I would do to try to get rid of those underextrusion holes in the side related to non-extruding moves.

That's a very very good bottom layer. I think you can do better. I don't think I've done better - well actuall I know I have in special case (call me gr5, not "moderator". There are other moderators). First of all to get leveling better you can't do it with leveling procedure - you have to do it by printing bottom layer and then adjusting screws. However you might already have it perfect. Anyway the trick to getting the bottom even better is to print it thinner. By default the bottom layer is .3mm because that makes it easier to get the bottom really good. But if you want to eliminate the lines even more then make the bottom layer .1mm. But now the leveling will have to be even better. While the printer is printing the skirt consider adjusting the 3 screws a little bit - I think you want it slightly closer. Alternatively you can adjust the flow. Maybe set it to 110% for the fist layer and then back to 100% some time during second layer.

Wait for the heated bed upgrade. It's worth the wait.