mr.-waldorf

I agree with you Aaron, some conclusion here...

Hi Aaron, Thanks It's film sticker carbon fiber. It is the same material used by the guys in car tuning to cover the hood. Works very well. Cheers

Hi Guys, More bad news, after 2 days without any changes, the underextrusion is back. Can't go over 6mm3/s and changing the flow % doesn't make any difference other day test with 100% Flow (failed at 4mm3/s) other day test with 90% Flow (passed at 10mm3/s) Today test with 100% Flow (failed at 6mm3/s) Today test with 90% Flow (failed at 6mm3/s) There wasn't no diferences between tests, even the room temperature was the same...

Hi My latest prints. hope you like... 0.1layer;30mm/s;230ºC 0.1layer;30mm/s;221ºC 0.08layer;20mm/s;230ºC red ABS and it's painted red ABS and it's painted red ABS and it's painted Hey, Don't forget the "like" button :mrgreen: Cheers

Hi IRobertI, Robert did you also sharpened the filament tip when that bubble appeared? can this be the cause of those "air bubbles"? I always cut my filament on a straight angle and never saw a filament tip as Nicolinux.

Hi Guys Another thought after openning a fine American apple cider! So if you think is stupid, I will claim that I was under the influence :blink: What about bowden tube lenght? Can a bigger bowden tube increase the springiness effect and cause the motor backwards steps? Can someone with good extrusion rates measure the bowden for comparison? Edited: Stefan have you seen already the nozzle hole(inside) with a magnifying glass?

I am so sorry. Damn your printer is haunted!! Maybe that hole in the filament tip is from a clog inside the nozzle. maybe abs or other garbadge from the extruder?on other end it's so perfect shape maybe Robert is right and it's from a air bubble. Dumping the nozzle in acetone for a while it's a good idea. Well, any good show must end with a bang, so maybe this litle guy can help? (can´t upload new photos...) Just kidding. Hey cheer up! Keep up the good work and you will find what is causing the problem

Hi Shafe, Love the topic. I am a HUGE RC fan and as former airborne soldier, I have a special affection for the Bug smasher (Herky bird) It's the Portuguese airborne mule! Wow, what a project! This is a huge project, I am impressed!! I am also used to build my planes and most recently I printed some detailed parts for my F-16 cockpit. I suspect that the weight will be a big problem. If I ever have the courage for a project of this size I would build the wings with the traditional method and print all the rest, meanwhile I will follow your thread closely and try to learn with your mistakes and surely I will be glad to help if and when necessary. Hey can't wait for the 1º flight video :cool: Have fun

Hey same here... can't upload :( Edited: Error The server returned an error during upload

Hi George As always very usefull info. Thanks I thought that reducing the Flow % would reduce some pressure and that could improve the extrusion. I think that this is not the solution of my underextrusion problem but this way I could achieve the 10mm3/s. There is more users that could overcame the underextrusion changing the flow % (Shurik was suceed with 80% flow) I can't find any fault on the nozzle head so I will try to increase the current. Right now I feel as in the begining, and don't now if I have over pressure in the bowden or if is the stepper motor that can't manage "normal" pressures. Are you always running with higher current, or you just changed to test? Thanks

Hi Nico Before changing the teflon coupler try printing the extrusion test with 90% flow With 100% flow I have underextrusion at 4 - 5mm3/s and with 90% flow I Made 10mm3/s without underextrusion. It's a way to overcame the motor jumps backwards and of course the underextrusion. Should be very interesting if you have the same results as I and after that you could change the teflon coupler and test the extrusion rate again with 100% flow

Hi Robert, Do you thing that it's the springiness stored in the PLA and bowden that causes the motor steps backards? I will print the some underextrusion test with lower flow % and play a bit with that. My teflon coupler and nozzle seems to be ok, so maybe its just a question to find a better flow% than the default 100%

Hi Anders Thanks. Not the case here. the filament guide even horsted the underextrusion Print illuminarti´s extrusion test at 230ºC. Maybe you have underextrusion but you didn´t notice because you are printing with lower extrusion rates if not it's always interesting to know that there is UM2 that can achieve higher extrusion rates

Hi Aaron, I made the extrusion test with the filament out of the bowden tube just running free in my hand and the motor didn´t jump backwards Made a second extrusion test and I tried to push the filament with my hand and then with a pliers and the motor didn´t step backwards. I was able to stop the filament and the motor just chewed the filament. Not the results that I was expecting... and I am not sure if this test results can mislead us I will repeat this test more times to see if there is consistency in the results

Also noticed that the 'backward jumps' are different in length. it's not a controlled movement Not saying that is this the problem but as the behavior of an electric motor with defective magnets, it slips under stress

Right before the stepper motor jumps backwards it seems to be a slight increase in nozzle pressure. That´s the reason why if we deacrease the flow we can avoid a litle bit the underextrusion. But doesn´t mean that the filament is not being able to flow out of the nozzle creating more back pressure. To me it seems that there is more back pressure but only due to higher flow rates and the stepper motor is underpowered. I have the feeling that the problem isn´t the nozzle head but the stepper motor or motor driver/Board. Meanhile I have to prove that! :mrgreen:

Same here. Few milliseconds after the extruder Jumps backwards

HA HA! Caught on camera on Valentine's day... The underextrusion occurs at: 3.23s 4.03s 4.30 4.50 5.23 Illuminarti's UM2 - Extrusion Test 3-10mm3 UM Gold PLA 230ºC Test failed at 4mm3/s The stepper motor is jumping backwards it seems a defective or underpowered stepper motor. think I have to further investigate, but not today. Happy valentine's day!

Hi Shurik, Put more tension into the bed springs and make sure that the springs are straight Repeat several times the level wizard because when you adjust one screw some times changes the bed level and you need to fine tune the others. Printing with 0.1mm inicial layer can be hard sometimes so as last resort you can try 0.2mm inicial layer Be careful too much tension on the springs is also not good

In my opinion is the most likely

:lol: :lol: :lol: I don't believe that is the extruder either, after some tweaks works fine. I was looking more carefull to the extrusion test photos, trying to understand your correlation. I can´t make that assumption/correlation just because of the regular pattern. However I agree with you, the source of the underextrusion problem could be there. I noticed that between underextrusions you have a few layers well printed (no underextrusion) which sends a little bit my nozzle theory down the drain. If the nozzle didn't have enough time to heat the filament at higher speeds It shouldn't have good extrusion between underextrusions. Don't think so! This is not an isolate problem on your printer. Did you noticed the views/replays of this thread? This is a widespread problem... Wow RESPECT Robert!! Awesome design and it works great. I will print one Thanks

Hey Nico, we are dead in the water again!! It seems that you have the correct nozzle diameter and gr5 only can make some measurements on monday. This will not help your problem but could explain george's extrusion rates, if he has a bigger nozzle hole. I saw that Ultimaker R/D team posted some comments on "Ultimaker2 Extuder System - Improvements and Ideas" topic so it seems that they also suspect of the extruder being the cause of some problems. Since they didn´t post anything here I can imagine that they don´t share with some of us the theory that a smaller nozzle hotzone is also causing the underextrusion at higher speeds. I really hope that new teflon coupler can solve your underextrusion problem, but i really don't believe it Meanwhile you realy have to change your UM2 rear, get a lazy susan or other way to feed the filament, because the stock way definitely cause underextrusion at higher speeds

Thanks yellowshark, very nice info. I noticed that with UM filament and you are quite right! Do you think that in overall Faberdashery filaments have a lower melting point than the others or they are very similar if we compare between same colors? or they are totally incomparable?

My most useful tool is this one: www.umforum.ultimaker.com

I certainly agree with you on this, and those guys are making a very nice job... Funny... I thought that Ultimaker filament was from Colorfabb, my mistake.