Some UM2 users are reporting under-extrusion problems, did you already tested your printer extrusion rates? You can download the *extrusion test here and should be printed at 230ºC
Should be interesting to know if this is a widespread problem or just a few isolated problems
Please post your results this can help you and others
No problem: gr5, Waldorf, Takei, illuminarti, Skint, Shurik, IRobertI (@1.5A), Rabanwin, MostlyAtomicBob(@teflon coupler), braddock(@new bowden tube), CanadaDrones(@friction free spool), Arska, colorfabb(@loosening the 4 screws on the print head), Pikey, Stuart838, Nicolinux(@new printer), Didier_Klein, WoofysPlace (new nozzle), Ju1050, tomkooij, Calimero, ProfePaco
MostlyAtomicBob, NicoLinux, Woofysplace, IRobertI, braddock, CanadaDrones, Geeks, colofabb, Shafe, Das_ENGINER
*Many thanks to illuminarti, it was him who made the extrusion test
illuminarti edit: For context, here's the link to the original posting of the test piece.
So my UM2 can't even print the first layer without the feeder skipping.
I have cleaned the nozzle out and the PLA is printing on my UM1 with no problem. (it's Faberdashery's Artic White)
I am at my wit's end with this UM2 it is causing me nothing but grief. Strange thing is that when I first got the machine (early December) it was amazing and i was printing at 210 deg perfectly. As time has gone by I have had to print at higher and higher temperatures.
I tried the test at 240 & 250 degrees and it still fails on the first to second layers.
I guess I will try and print Takei's feeder on my trusty UM1 which is still working fine 11 months and thousands of print hours later.
I will try the test later after work. At the moment I am getting better results printing PLA at 210-220max, I will try the 230 and edit this later with results.
Quote by MostlyAtomicBob
Strange thing is that when I first got the machine (early December) it was amazing and i was printing at 210 deg perfectly. As time has gone by I have had to print at higher and higher temperatures.
My own UM2 was also much better when I first got it. PLA used to pour from the nozzle at the start of a print leaving a long trail up to the start point. It was fine right up to my first nozzle clog and has been struggling ever since. Now its usually 100mm around the brim before the flow gets going. I wonder if the inside of the nozzle is tarnished with some oxide that's preventing efficient heat flow.
I've measured the diameter of the extruded filament so I'm sure the nozzle diameter is ok.
I can push filament through the hotend by hand at 200deg with very little effort. I am pretty sure it is achieving the correct temperature.
I'm fairly sure the problem is with the extruder stepper or the feeder mechanism. If i adjust the tensioner on the feeder to anything above the lowest position(lightest pressure) the motor just skips constantly.
If i want to print anything ATM the first layer has to be about 230degs 20mm/sec and 90% flow and it still skips. After that If I have to print 0.1mm layers at 40mm sec but still get random skips throughout the print.
When I first got the printer i was happily printing at 210-220 degrees, 60mm/sec, 0.2mm layers. With no problems what so ever.
Will this file work for the UM1 also?
Would be interesting how the UM1 can handle the 100mm/s
Skipping on the first layer is mostly a sign that your bed height/level is off - that's the hardest layer to print since the bed surface restricts flow, and if the bed leveling is off, you end up trying to push out for filament than will fit through the gap. Remember to level a UM2 to a papers width off the bed, not touching, and try with a thicker, but slower first layer, so that any leveling error is a smaller percentage of the head height.
The file won't work on a UM1 as it is UltiGcode, and lacks the necessary start gcode preamble, and has the wrong e-coordinates. There's been a lot of testing of this sort on a UM1 however, and while people's experiences vary quite a bit, the upper limit is around 8-10mm3/s for a standard UM original.
I would expect some natural variation on the UM2 as well - I'd say that anything at or above 8mm3/s is a perfectly reasonable result: most printing occurs at far lower speeds.
Skipping on the first layer is mostly a sign that your bed height/level is off
I think atomic bob means "the first section" not "the first layer". I think he meant the first layer that is at the slowest speed and is about 20 layers or something like that.
Quote by Mr. Waldorf
gr5 edit: waldorf lets post summary here:
no problem: gr5, waldorf, takei,illuminarti
Good idea George. I Will try to update the summary.
Quote by WoofysPlace
My own UM2 was also much better when I first got it. PLA used to pour from the nozzle at the start of a print leaving a long trail up to the start point. It was fine right up to my first nozzle clog and has been struggling ever since. Now its usually 100mm around the brim before the flow gets going.
Hi Woofysplace, should I add your printer to the problems list? maybe after you check the nozzle?
Actually I did mean the first layer, the bed levelling is spot on (pro at that these days)!
I read through a fair chunk of the Under extrusion thread and decided strip the hot end down.
I removed a couple of burs from the PTFE and Bowden tube and I added a little chamfer to the inside diameter of the Bowden.
This has helped massively. I can now print the above test but it starts to under extrude at 6mm/3/sec.
Still work to be done but a lot better than at 9am this morning
Well, I finally got my ass in gear again and got my new feeder design mounted for a test. I got a couple of layers into the "6"-section before it started skipping, so a slight improvement IIRC from previous tests.
I then decided to try altering the current. I hadn't bothered to try this because of gr5's tests that seemed to indicate it would be a waste of time. Well... it sure wasn't a waste for me! I upped the current to 1.5A and got all the way through 10mm<sup>3</sup>/s without a single skip :eek:
Now, let's hope Daid sees it and adds a menu entry for the UM2 firmware where the current can be set.
Quote by Mr. Waldorf
Hi Woofyplace, should I add your printer to the problems list? maybe after you check the nozzle?
Here are the results of trying the motor current settings:
The first picture is the supplied test at 230.
The following is with the motor current set to 1.5A:
I then tried again at 1.75A, but the extruder chewed the filament while still on the skirt.
Then it seems like there is something mechanical that is restricting the movement of the filament on your printer, WoofysPlace. If the motor is pushing the filament hard enough to chew it up, then should be capable of exiting the nozzle much faster than 4mm³/s.
I think some of it may be the orange UM filament is almost at the end of the spool and quite sharply bent.
I'll try again with a new spool.
That could certainly be part of it; I've been able to induce failure by deliberately loading fairly tightly coiled filament in such a way as to maximize the tension on the filament in the bowden tube.
Here's the result of a new spool of UM Red. Its located under the bench with the curve aligned as per the bowden and free to move (as was the orange).
This is the default print at 230.
and with the motor current set to 1500:
and again it failed to extrude at 1750mA.
Woofy... man thats dissapointing Give me a few minutes and mine will be complete ( i hope ) second time around
That is indeed bad news. I should probably re-print and make sure it wasn't just a fluke... Or maybe my feeder has something to do with it not grinding the filament down. Kinda doubt it though.
Please see http://umforum.ultimaker.com/...or-ultimaker2/page-3,(#41) because we both think that increasing the current may worsen the problems in the near future (we can be wrong, it's to soon to draw any conclusions)
OK here it is, printed 230. Man! is scary isnt it ?
This was my second time around, first time skipped at 5ish, but I am 99% certain it was a dodgy coil in the filament ( i heard that scratchy noise when it pulls and witnessed the skip mark immediatly ),
I changed nothing.... and started again.
So..... Got to 9mm & 10mm before there was any visible "errors", you can see these within the lettering and next to the squiggly line on the left. Not a bad effort though...Wipes brow!
Edit. PS Why didnt someone put a base on the bottom of it, atleast I could use it as a cup
One thing I want to do is replace the nozzle block. l posted a support ticket this morning asking for a replacement nozzle and teflon part. I'll pay for them if needed. I also pm'd the request to Sander. No response from either as yet.
Congratulations! You have the best printer on the Market and is working well.
I know that you have your printer at short time but it seems that some users report problems after some use, hopefully this is not the case and that you have a perfect condition printer
Many thanks for the tests and the posts