I was referring to the still of the Ultimaker videoI think we have a very different definition of a good top surface...
The test object hast six layers for the bottom/top surface. It should be enough.
I totally agree there's room for improvement in the red cube I printed.... I'll try to find time for some maintenance on this machine in the weekend and see again...
@SandervG: I think it is partially a software and hardware issue (the board mostly).
How many mm was the spring compressed when it was at its best? And you use the original UM2 spring I assume?
It is the original spring but there have been some revisions over time. I remember some original feeders required the user to have the tension set a few notches up, where as with my spring, I had to set it to the most relaxed tension.
The compressed spring is 9mm long. Since I have added a few shims, it is a total of 12mm between the feeder body and the screw cap.
Some updates that might be helpful.
After having lots of trouble,I removed the small black ring that was between the brass hotend and the white teflon.
The things did improve but not quite sufficiently. There were yet some strange under-feedins of the material. So, I took the tension yoke off my Robert's feeder, and it looked very interesting:
Once the yoke being replaced, the extrusion test went from this
to this:
It started to click on 9mm3 and stopped with "Temp. sensor error" in the mid-10mm3.
And here is the cube of @Nicolinux:
Bottom layers:
The whole cube:
Colorfabb White, 210C.
Sorry for the quality of the phone camera.
While not 100% perfect, it looks OK in the reality.
So, could it be that your feeder motor or the yoke from the other side of the filament are not aligned properly or something else obstructs the feeder flow?
Not quite sure what to do with that temp. sensor error, though. It appeared once or twice before, during the nozzle cleaning heatups, so I disregarded it up until now.
Edited by GuestNice @shurik, so there is some improvement.
And good thing you mentioned the feeder. I looked at mine and found something odd too. In its nominal state it looks like this:
I noticed sometimes the filament is not centered on the bearing and moves to the front. Usually this would make the filament snap off the bearing but I have printed a modified yoke that has a small guard to prevent it. But this guard increases the friction and may lead to under extrusion too.
Besides the yoke is quite beat up. I think I should replace it.
Printed the extrusion test. The first one failed at 10mm^3/s which is ok. But for the second one, I remember it failed later on.
My printer had the issue with original feeder and new Roberts feeder. It also would print the extrusion with no problems.
- 1
Ok, I have tested the extruder accuracy. Took the bowden from the head and used PrintRun (also known as Pronterface) to extrude manually. Don't forget M302 to allow for cold extrude. And there is a bug on the Mac version where you have to enter values with commas "10,0" for 10 mm _and_ press enter twice after entering the value...
I set it to extrude 50mm and measured 50.7mm and 50.4mm. There is a little slack through the bowden tube so it is not entierly possible to measure very accurately. But still, this value tells me that there is at least enough material extruded. If it were to be less than 50mm then I'd think about this as a cause for under extrusion.
Try doing the same thing but while extruding material. I think you'll find that the distance will be reduced quite a bit. If you look at the teeth marks on the filament you'll see that the spacing between them gets smaller and smaller the faster you print. At least that's the case for me. Easiest way to do it is to simply make a mark right at the entrance of the feeder and then another mark after you've extruded Xmm of filament, open the feeder up, yank the filament and measure.
Also, I'm not surprised that people aren't seeing any improvement with my feeder. Honestly the intent was more to make it more convenient to use than anything else
I've also noticed that the filament moves a bit more across the bearing when using the grommet version of the body. The bowden-snippet version doesn't seem to have as much of a problem with that. I assume that's because the bowden diameter is much smaller than the grommet so it doesn't allow for as much play. I'm thinking of switching the feeders on my XT and Go to the oldest version I can find on my computer because honestly it worked better before I started trying to please everyone
Alright, I understand the problem. Will redo the test.
Speaking of the feeder - I do sense a slight hint of bad vibes around the pleasing everyone issue. You need to keep in mind that you still made the best feeder for the UM2. Success produces headaches at times...
Yeah, it's just that after you've gotten the 20th PM asking "What screws do I need?", "could you change this to fit printer X?", "This piece is too long, can you make it shorter?", "This is too short, can you make it longer?", "This didn't come out right on my printer, can you change this part?" it gets old...
My favourite is when people ask how to assemble it though. Even after I've posted several pictures and even a video showing how it goes together.
But, I'm de-railing the thread so I'll shut up now
- 2
Ok, I got a bit desperate here. No matter what I tried, there was constant under extrusion. This gap between the PTFE coupler and the nozzle is the culprit (I think). (highlighted in red)
When I do an atomic pull, the filament tip looks weird too. Could it coincide with the gap?
I have swapped the Olsson Block with the 1.75 version that I have here. The same .gcode file printed with the very same settings looks perfect... WTF? (I had to play with the colors a bit in order to make the "no gaps" visible...)
Good news everyone,
The problem might be solved. @neotko had the killer tip to add a ferrite core to the feeder motor cable. I did it and the result is marvelous:
Before adding the ferrite core I installed the 2.85mm Olsson Block and did a test print. The surface was awful and there was under extrusion on the outside walls too. After adding the ferrite core the next print looks like the image above.
Having ordered too many of those thingies I added them everywhere
Printed again. This time it doesn't look as good as before. I don't fully understand how the ferrite cores work but can too many of them be bad too?
Sorry but seeing that many ferrites block hanging just made my day XD!!
So happy it prints better!!!
Dim3nsioneer 557
@Nicolinux: I wonder if you would have the same problem with a different infill pattern? The new Cura e.g. allows for concentric infill. That might give some new hints about the origin.
On my setup I added just one 3-4cm away from the extruder and also warped it with a cable plastic stuff (like the one that goes around the cables on umo but thinner). But I keep the cable away from the stream just to forget about this error. I don't know if many ferrites are good since they are little magnets warped in plastic. I don't think that near the board should be good. But again congrats on printing close to normal
Could you explain why this helps?
My expertise doesn't reach that far
Could you explain why this helps?
My expertise doesn't reach that far
My expertise it's probably the same XD (designer, accountant and 3d printer for a year with zero electrical knowledge, except what I have Learn since I got this printer. (i clap to myself by having desolder and solder an smd transistor chip)
My theory it's explained on the previous page:
https://ultimaker.com/en/community/view/6375-top-layers-not-touching-um2?page=18#reply-120951
Edited by Guest- 1
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They shouldn't have used your printer for the demo
(sorry, I have to make fun of this issue or else it would drive me mad).
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ultiarjan 1,223
To me this just shows you need an x number of layers to get a good surface.... no issue here I think...the top layer looks good.
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