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Can your UM2 printer achieve 10mm3/s ??? Test it here...

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

I sure dont' know. I don't know the difference. I think probably PTFE though.

 

There is no difference. PTFE is the abbreviation for Polytetrafluoroethylene, Teflon is the trade mark for this material by DuPont.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Hey Gr5,

Thank you for your advices. This has really helped. Obviously I was a little too close to the glass plate...

Ultimakers instructions for leveling allows a certain range of interpretation :-P

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

I did the cylinder print and have happy/sad/mystery results.

First I cleaned the nozzle by heating it up, stuffing in filament, cooling to 90 then pulling out filament. (This technique needs an official name. Maybe after the person who first posted about it, who ever that is.) I have mentioned previously that I am not very patient sometimes. The nozzle heats up nicely, but cools way too slowly. I have been dipping a paper towel in water and holding it against the nozzle to cool it off. Unless someone says this is a really bad idea, I will keep cooling it that way to speed up the process. Did that several times until the filament came out the same color as it went in. Next I inserted a steel wire that measures .37mm into the hole. That is as clean as I can get it without soaking in acetone or something else.

I loaded the Ultimaker blue PLA that came with my UM2. The spool is below the printer hung on a piece of pipe. Set temp to 230 and waited. The extruded started skipping at 7mm3/sec. I then switched to some PLA I purchased from Makershed. It behaves differently. Did the same test. Skipping started at 4. I switched back to the blue and waited. My wife said something about me paying more attention to the printer than her. I'm not really sure what she said. I was listening for the extruder to skip. This time it finished the cylinder 100% correctly, all the way to the top!! When it was done she said maybe she should get some toys of her own so she could entertain herself. I'm not sure what that meant, but it didn't sound friendly so I quit for the night.

This morning I tried again. Nothing had changed from last night, just the time of day. The blue was still in the machine. I started and waited. As I sat there I heard the spool quickly unwind. The sound it makes when the filament explodes off the spool if you don't hold it tightly in place. Right after that happened there was an extruder skip. It was at the top of the 7 ring. I aborted and started again with the blue as always at 230C. The extruder started to skip at the top of the 5 ring.

My conclusion from this is that the position of the filament as it goes into the extruder is very important. Most of you likely have the same conclusion. I will try again with the spool on the stock spool holder to see what happens. My plan is to print a cylinder and abort when the extruder skips. Clear out the machine and print again several times in a row. Hopefully I can get 3 or 4 cylinders that fail at about the same place. The randomness of my cylinder tests so far is confusing.

I have also concluded that my UM2 can be awesome. Hooray!! It is a little tricky to get to awesome however. The filament must be aligned properly with the extruder, Jupiter and Venus, and the lunar gravity must be at a right angle to the polar vortex above The Netherlands.

As I said before, I cannot offer much other than confirming results on my machine. So I say "Go team! Go!"

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

A buddy just had an awesome suggestion!! It is so obvious I'm shocked no one has considered this. I will get to work right away modifing my UM2 for the Turbo Encabulator upgrade. I think I have a source for the Spurving bearings which will need to be smaller than the original design.

Given the overall "geeky" nature of the people participating in these topics I suspect most of you are familiar with the Turbo Encabulator. For those of you who have never heard of this amazing device here is a link:

 

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

If English is not a familiar language for you, my post above is only a joke. There is no such thing as a Turbo Encabulator.

According to Wikipedia, the Turbo Encabulator dates back to 1944. Who knew??

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

My wife said something about me paying more attention to the printer than her. I'm not really sure what she said. I was listening for the extruder to skip.

 

:-P :-P :grin: :grin: :D :lol: :lol:

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Hi Guys,

I found that if you overtighten the 4 headscrews this also causes under extrusion. I loosened the 4 head screws and now I can achieve 12mm3/s even with a half empty spool.

Try loosening the screws as far as it can, keeping together the plastics.

(could be necessary to re-calibrate the bed)

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Also don't overtighten the extruder encasing. ABS is quite soft and might give in, increasing pressure on the passing filament.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Hi Guys,

I found that if you overtighten the 4 headscrews this also causes under extrusion. I loosened the 4 head screws and now I can achieve 12mm3/s even with a half empty spool.

Try loosening the screws as far as it can, keeping together the plastics.

(could be necessary to re-calibrate the bed)

 

Very interesting find Mr. Waldorf. Since it's so simple to implement, I am excited to see the results of other members in this thread after making the adjustment.

By how much would you say you loosened the four bolts? Is the black plastic holding the head together noticeably looser or is it still snugly fit together just not too tightly?

I wonder if because the knurled portion of the bolt is so large, that over tightening it is a common mistake when UM assembles the units.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

The only reason I can see for that helping is if the bowden is pushed down too far before tightening so that the bowden tube gets deformed and constricts the exit. Or am I missing something?

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Just tried it, made no difference at all for me.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Hi Aaron,

I loosened the 4 screws the most I could but keeping the black plastic snugly fit together just not too tightly

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

The only reason I can see for that helping is if the bowden is pushed down too far before tightening so that the bowden tube gets deformed and constricts the exit. Or am I missing something?

 

Hi Robert,

I am not sure, but I think you are right. I can't figure out any other reason.

At the moment, I continue to have success with the extrusion tests at 12mm3/s so I am very pleased with my printer is finally well tuned

Hey Woofysplace, maybe its time to send your printer to UM !?

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Hey Woofysplace, maybe its time to send your printer to UM !?

 

Not yet, I really don't want to send it back at all. When I print slowly the print quality is fantastic.

I have a support ticket in requesting a replacement nozzle and teflon part.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

I got a chance to test another new UM2 yesterday, and this was the first one I've seen that failed below 10mm³/s. it started to skip at 7mm³/s, and was pretty poor by 8. Increasing the current setting to 1500 improved the result a little bit - first skipping happening at 9.

So, I took the printer apart, to see if I could identify any issues. The nozzle was perfectly clean and unobstructed, and the filament passed through the teflon part and into the nozzle without any kind of hindrance at all. And the motor end, Everything seemed fine - I could see where the ABS casing had already started to abrade very slightly where the filament passed into and out of the channel past the knurled drive, but it was barely noticeable at this point, since it's a brand new printer.

There was a tiny lip of metal from the dibond panel that I tore away on the inside of the case, where the motor sits down onto the nut that holds the case together; that might have held the motor fractionally further off the panel, but not by much.

The Bowden was clean and undamaged. When I tried to feed some filament up the Bowden tube from the hot end, by hand, I noticed two things. First, it seemed that there may have been some obstruction, around the area where the tube passes through the retaining clip on top of the hot end. But maybe it was just catching the edge of the filament somehow... the obstruction quickly freed up, and then the filament ran pretty smoothly after that.

I did notice however, that if the filament was rotated just right, against its natural curvature, it became very hard to push it through the Bowden - I could certainly see why the motor might struggle with the filament in that orientation.

When I put the printer back together again, I got better results - it now didn't start to skip at all until 10mm³/s. Exactly why it worked better I don't know - perhaps the angling of the motor is better now, or maybe there really was something restricting the bowden slightly. But there certainly wasn't anything obviously wrong with any of it - I think it may just be a conjunction of several circumstances that together prove to be too much for the extruder - but if I had to pick one, I definitely think that filament curvature is probably the single biggest contributor.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

well, not surprised by my results. The orange test is almost at the end of the spool, but the white is virtually unused.

temp: 230

 

Ex test white

Ex test orange

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

What temp did you do? I get the same results if I lower the temp enough... Please edit your post and mention the temp.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

edited now (230)

 

What temp did you do? I get the same results if I lower the temp enough... Please edit your post and mention the temp.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Ok, some interesting results tonight, but firstly... I'm embarrassed to ask, but what do the numbers on the test print mean? I know it means speed, but why not write 30mm /s etc? what does the small 3 indicate?

Anyway... here's my results, all I did, was squirt inox down my bowden tube. (inox is like WD40, an anti corrosion lubricant)

I manged 3 completed extrusion test... this is remarkable given my previous tests above with the same white filament at 230

First test, I realised I was printing at 80% speed. I noticed this at the 8mm mark... so I turned it up to 100 expecting it to fail, but to my surprise it kept going.

I decided to test again at 100% speed from the get go to make sure... oddly, it had a slight under extrusion right at the bottom (could have been the fault of some inox dripping out, or a filament snag) but, it recovered and continued all the way to complete a perfect test.

3rd time was the decider, and again, it had one momentary under extrusion midway through 4mm, but recovered and completed perfectly.

What does this mean? Is the bowden tube itself simply too tight? is there a way to set up a jig to run a test print without the bowden tube?

 

extrusion tests

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Ok, some interesting results tonight, but firstly... I'm embarrassed to ask, but what do the numbers on the test print mean? I know it means speed, but why not write 30mm /s etc? what does the small 3 indicate?

 

Speed on its own is meaningless. You need the layer height as well to calculate the volume per second the extruder is capable of. printing at 30mm/Sec 0.2mm layers is the same as 60mm/Sec with 0.1mm layers.

So 3mm3/S means 3 cubic mm per second.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Well my problem appears to be fixed.

Ultimaker are sending me a replacement PTFE piece but I have a lot of work deadlines this week so I went and turned up my own replacement (the joys of a full propmakers workshop at my disposal!)

and the results on the first test were flawless:

EXT test

 

Printed in Faberdashery Pearl at 230deg

 

I have run another test to make sure it was not a one off, and again not a single skip from the extruder.

 

However the question is how did the PTFE part get deformed in the first place?

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Hey MostlyAtomicBob, I think your findings are pretty interesting. I hypothesized the tefon couple could cause under extrusion on pagest 2 and 19 of Nicolinux's mega thread here. Definitely print another cylinder, maybe even a couple more cylinders, just to make sure it wasn't a fluke; I'm very interested to see your results.

Regarding how the teflon coupler gets deformed in the first place. I believe it's from Creep (deformation): http://en.wikipedia....p_(deformation) and too much compression force on the teflon coupler. The wiki page on Creep Deformation is pretty interesting and talks about how susceptible plastics are to the phenomena. Essentially with increasing temperatures plastics will deform under pressure; I'm still not sure why the teflon coupler was chosen. I am not criticizing the implementation of the teflon coupler, I just think there are tons of other materials that could have been used, high durometer silicone rubber, carbon composite materials, even temperature suitable glass. I suppose there are trade-offs with the aforementioned materials and I don't have the perspective their engineering department has, but it seems like that piece is the weakest link in the extrusion system; perhaps without the presence of increased pressure from assembly, the teflon copuler is the best choice. I know the heat sinks are suppose to wick away heat before it hurts the coupler, but I think the teflon piece is still getting too hot due to its close proximity to the heated portion of the nozzle.

 

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Posted · Can your UM2 printer achieve 10mm3/s ??? Test it here...

Great to hear @braddock :-P!

I can't find the post now, but either Daid or Sander suggested to spray some WD-40 in the bowden tube to see if it would help. I'm glad that such an easy fix helped you in your case; I suppose it's another thing to add to the list of fixes that work.

 

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