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Prints quality not the same as it used to

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Posted · Prints quality not the same as it used to

Whoa, burnt looking electronics are never a good thing.

Is the LED strip being chewed up by the pulleys?

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Posted · Prints quality not the same as it used to

A bit at the end but not much, it was hanging around between the two pulleys; not really affecting anything, the glue was wearing off I guess or the leds were burning too hot.

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Posted · Prints quality not the same as it used to

This newer angle is a better camera angle than the first image. This is underextrusion. Something tricky to fix so you have to start eliminating things. Here is my generic underextrusion response below. Please read them all in case one stands out (e.g. maybe you printed with CF filament once in the past) but most likely your TFT is fine (it looks fine in the photo) so most likely I'd start with #1 below.

====================================================

CAUSES FOR UNDEREXTRUSION AND HOW TO TEST FOR THEM AND REMEDY THEM

As far as underextrusion causes - there's just so damn many. none of the issues seem to cause more than 20% of problems so you need to know the top 5 issues to cover 75% of the possibilities and 1/4 people still won't have the right issue. Some of the top issues:

1) Print slower and hotter! Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers) and .4mm nozzle:

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

2) Shell width confusion. Shell width must be a multiple of nozzle size. For example if nozzle size is .4mm and shell width is 1mm cura will make the printer do 2 passes with .5mm line width which is possible but requires you to slow down much more to make a .5mm line out of a .4mm nozzle. If you really want this then set nozzle size to .5mm so it's clear what you are asking Cura to do for you.

3) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 500 hours. It gets soft and compresses the filament under pressure. It's the white part touching the heater block. It's very hard to test when not under full pressure (spring and bowden) so sometimes it's best to just replace it. Also if you notice parts of it are very soft (the blacker end where it touches higher heat) then it's too old and needs replacing.

4) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test.

5) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference.

6) Head too tight? Bizarrely MANY people loosen the 4 screws on the head by just a bit maybe 1/2 mm and suddenly they can print just fine! Has to do with pressure on the white teflon isolator.

6b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator.

6c) Spring pushing too hard. Although you want a gap you want as small as possible a gap between teflon isolator and steel isolator nut such that the spring is compressed as little as possible.

7) clogged nozzle - the number one problem of course - even if it seems clear. There can be build up on the inside of the nozzle that only burning with a flame can turn to ash and remove. Sometimes a grain of sand gets in there but that's more obvious (it just won't print). Atomic method (cold pull) helps but occasionally you need to remove the entire heater block/nozzle assembly and use flame. Or soak it in acetone overnight (after removing 90% of the material with cold pull).

8) Temp Sensor bad - even the good ones vary by +/- 5C and bad ones can be any amount off - they usually read high and a working sensor can (rarely) fail high slowly over time. Meaning the sensor thinks you are at 220C but actually you are at 170C. At 170C the plastic is so viscous it can barely get out of the nozzle. You can verify your temp sensor using this simple video at youtube - on you tube search for this: mrZbX-SfftU

9) feeder spring issues - too tight, too loose

10) Other feeder issues, one of the nuts holding machine together often interferes with the feeder motor tilting it enough so that it still works but not very well. Other things that tilt the feeder motor, sleeve misaligned so it doesn't get a good grip. Gunk clogging the mechanism in there.

11) Filament diameter too big - 3mm is too much. 3mm filament is usually 2.85mm nominal or sometimes 2.9mm +/- .05. But some manufacturers (especially in china) make true 3.0mm filament with a tolerance of .1mm which is useless in an Ultimaker. It will print for a few meters and then clog so tight in the bowden you will have to remove the bowden from both ends to get the filament out. Throw that filament in the trash! It will save you weeks of pain

11b) Something wedged in with the filament. I was setting up 5 printers at once and ran filament change on all of them. One was slowly moving the filament through the tube and was almost to the head when I pushed the button and it sped up and ground the filament badly. I didn't think it was a problem and went ahead and printed something but there was a ground up spot followed by a flap of filament that got jammed in the bowden tube. Having the "plus" upgrade or using the IRobertI feeder helps you feel this with your hand by sliding the filament through the bowden a bit to see if it is stuck.

12) Hot weather. If air is above 30C or even possibly 25C, the air temperature combined with the extruder temperature can soften the filament inside the feeder such that it is getting squeezed flat as it passes through the feeder - this is obvious as you can see the problem in the bowden. The fix is to add a desk fan blowing on the back of the printer. Not an issue on the UM2 "plus" series.

13) Crimped bowden. At least one person had an issue where the bowden was crimped a bit too much at the feeder and although the printer worked fine when new it eventually got worse and had underextrusion on random layers. it's easy to pull the bowden out of the feeder end and examine it.

14) Small nozzle. Rumor has it some of the .4mm nozzles are closer to .35mm. Not sure if this is actually true. I'm a bit skeptical but try a .6mm nozzle maybe.

15) CF filament. The knurled sleeve in the extruder can get ground down smooth - particularly from carbon fill. 4 spools of CF will destroy not just nozzles but the knurled sleeve also. Look at it visually where the filament touches the "pyramids". Make sure the pyramids are sharp.

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Posted · Prints quality not the same as it used to

wQbqjNc.jpg

230°C. My temperature sensor miscalculate of 20°c then, nothing I can do except change it ? It's going to be a pain to change it everytime I print something.

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Posted · Prints quality not the same as it used to

I don't understand. How do you know the temp sensor is off by 20C?

You can change your default printing temperature. On the printer go to materials settings then choose CUSTOMIZE. Change the temperature, then SAVE then choose PLA to save to the PLA slot.

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Posted · Prints quality not the same as it used to

Oh thanks I was doing it every time I print in "Tune".

For me it's off by 20C because it's where I get the best print. Can this be fixed by the warranty ?

Anyway, thanks for your answers guys, really helped.

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Posted · Prints quality not the same as it used to

warranty? Fixed?

I still don't understand. Are you saying you have an accurate way to measure actual nozzle temperature and the nozzle is 20C cooler than the printer says it is? If that's what you are saying then this is normal and expected. That's why you can't copy "temperature settings" across printers. The heat flow of the print head is different for every printer. The temp sensor is very accurate but only where the temp sensor is located. The temp sensor isn't inside the nozzle.

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Posted · Prints quality not the same as it used to

No I don't have a way to measure the temp but since it worked great at the beginning on 210 and now I have to set it at 230, I thought it was the temp sensor that was off. At least something change that maybe could been fix if I send it to repair (also the leds are hanging :/). What do you think ?

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Posted · Prints quality not the same as it used to

The temp sensor is very unlikely to change by 20C like that. They can fail because inside the temp sensor they are crimped and not soldered and the crimping can loosen as it warms up but this failure mode looks very different from yours. It doesn't change by just 20C (about 1 ohm) but instead changes by at least 50C and it changes suddenly jumping up in temperature. The temperature bounces all around from second to second.

Back to your issue. It used to print fine at 210C and now you "have to" set it to 230C. This sounds pretty normal. Maybe it's because you are printing a little "faster"? "faster" means thicker layer height or wider traces or faster print head movement.

For example in cura if your nozzle is set to 0.4mm and your shell width is set to 1mm then it makes two 0.5mm passes which is very difficult for a 0.4mm nozzle.

Or maybe your teflon part needs replacing. In the printer menu you can check how many hours you have printed. If it has been > 500 hours it's probably time to change the teflon part. Even 100 hours at 250C might be enough to weaken the teflon part. or maybe you are printing with a different color of filament that needs higher temperature.

I listed 15 causes of underextrusion above. You might want to think about each possible cause and try to eliminate them. Raising the temperature to 230C will help reduce underextrusion but the cause may be one of the other possibilities.

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Posted · Prints quality not the same as it used to

Woah. I didn't think I printed that much : 430h.

By setting it at 230C I haven't got one problem in 20h of printing, so that's nice.

Still two points from your list I haven't tried that could be the problem too, gonna get on it.

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Posted · Prints quality not the same as it used to

If you printed +400 hours on an UM2, even at only 210°C (PLA), then the teflon coupler will definitely be deformed and need replacement. Whatever else there may still be. So I would suggest: do yourself a favour and replace it.

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