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MarcoUbtz

Print Quality Issue

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Hello all,

Since a couple of weeks I had a quality issue with my printer.

My problem consist in something like over/under extrusion wich cause an ugly layer allignement in the z direction, or at least that would seem.

I've done a lot of prints to search the cause of the issue, from the slicer, firmware until the mechanical side of the printer.

Here are some pic

1.thumb.JPG.454e0336f6aa1a80025c78dceb6e2264.JPG

2.thumb.JPG.d0fdf9d5cc0df796db03175fd6594962.JPG

9.thumb.JPG.f13052e4a6e82693c26a000cbd7c9d57.JPG

10.thumb.JPG.c6331170136f92294411508c98a2a1cd.JPG

22.thumb.JPG.a30bac3b3eb6aa8311116e1e2f44db9c.JPG

23.thumb.JPG.f291d7d8695780a2182c7fe86588e36e.JPG

32.thumb.JPG.9f9d7710d4e9057d5972fcbbe6fe5288.JPG

33.thumb.JPG.b1009e74ba1f1d732bb5a0c4ba21df4b.JPG

The printer in question is an UM2Ext with olsson block and bondtech feeder.

The materials used in those tests are all Colorfabb PLA except the white one that it is GreenTec.

The quality is 50mm/s, 0.2mm layer, 200/210 / 55 degrees. Here is also the gcode

I've already checked:

- extruder PID

- TFN/PTFE coupler is not worn

- heater and PT100 are inserted until the end in the block

- the PT100 has a fine accuracy

- I've done a lot of atomic, all was clean

- I've done different prints with different temp and different material, no quality changes

- The spring pressure of the feeder is fine

- The gear of the feeder is clean

- I've done the same test also with bowden and the ZGE setup, the results were the same with the same issues

- I tried different firmware versions with a factory reset betweet the switches

- I check the e-step, the current of the steppers

- I checked the eeprom parameteres with M501

- I tried different speed for printing, travel and Z moves

- The tension of the long and short belts are good

- The XY allignement also are good

- The bearings are good too (I checked all the flangeds, linears and the bushings one)

- I verified if the shaft (12mm, 8mm, 6mm) were straight too

- I disassembled completly the build platform from the printer, the z screw is perfect, the bearing roll very good an the nut has an imperceptible play

- I putted a 850g weight on the bed. no differences

Yesterday I rod somewhere in the the UM forum something about the bed PID and the bang-bang mode, the thread talked about the 14.XX firmware.

I tried to set the bed PID [kp=-124.55, ki=23.46, kd=165.29] and here is the result

36.thumb.JPG.8deb891bc4a37148e16f243598d58878.JPG

bed @60

44.thumb.JPG.16b453d264f4ced2cdc0db17f1cad674.JPG

bed@60

40.thumb.JPG.dee23c58dfccb48edde6d0885988891c.JPG

bed @0 forgot to apply the glue

48.thumb.JPG.879ab19873687713884827248dbf29cb.JPG

bed @0

the issue seems to have diminished but it is not disappeared.

Now, after a lengthy explanation of the problem.

How can I resolve this quality issue?

Can someone help me to return the print quality to an acceptable levels?

Regards, Marco

1.thumb.JPG.454e0336f6aa1a80025c78dceb6e2264.JPG

2.thumb.JPG.d0fdf9d5cc0df796db03175fd6594962.JPG

9.thumb.JPG.f13052e4a6e82693c26a000cbd7c9d57.JPG

10.thumb.JPG.c6331170136f92294411508c98a2a1cd.JPG

22.thumb.JPG.a30bac3b3eb6aa8311116e1e2f44db9c.JPG

23.thumb.JPG.f291d7d8695780a2182c7fe86588e36e.JPG

32.thumb.JPG.9f9d7710d4e9057d5972fcbbe6fe5288.JPG

33.thumb.JPG.b1009e74ba1f1d732bb5a0c4ba21df4b.JPG

36.thumb.JPG.8deb891bc4a37148e16f243598d58878.JPG

44.thumb.JPG.16b453d264f4ced2cdc0db17f1cad674.JPG

40.thumb.JPG.dee23c58dfccb48edde6d0885988891c.JPG

48.thumb.JPG.879ab19873687713884827248dbf29cb.JPG

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The PID bed indeed could be the issue.

You did set bed pid, but did you change the firmware? For example on UM (umo+, um2, um2+) the official firmwares are on bangbang mode, to use PID on the bed you need to build your custom firmware OR just install tinkergnome firmware.

Oh I see with bed off you get that too.

You use zge but with bowden that also happens? I mean, with zge the z noise can be almost removed with the z dampening change. But if that shows on bowden then I’m not sure except there’s some kind of play on the head bearings or the axes ain’t fully squared.

Other crazy idea. Try the same test without fan, even if gives bad quality because lack of cooling. Just to check the fans don’t affect the hotend temperature.

Edited by Guest

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I already use the TinkerGnome ones, I changed the pid from the menu on the printer. And yes, with bowden setup I have this issue too. Last week I tried also to test with a different hot end, same results.

I just run the same gcode with 100%, 75% and without fan. Here are the results.

From left to right, 0%, 75% and 100% fan.

F_0_75_100.thumb.jpg.e08d5c20159bc29d98354f7aa1da170e.jpg

The one without fan is a little bit melted, but the results are nearly the same.

Now I will re-check the head bearings, the pulley and the XY allignement

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Just throwing spaghetti to see if something sticks

Can you check the 4 8mm smooth rods if they wooble up/down?

giphy.gif

I had this looong ago on 2 umo+ and in the end I just replaced all shafts with misumi/igus ones for precision

This was 2 years ago when I was even bigger a noob

https://ultimaker.com/en/community/16964-umo-woobling-x-block-sometimes-y?page=last

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I just realized that a 8mm shaft is not as straight as I thought. It swings up and down something like 0.05/0.1 mm, now I don't have it at hand but tomorrow I will check better with a dial gauge.

It is a little bit embarrassing I have not noticed it

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I asked you this simply because I would not have any surprises once I've replaced XY shafts and bearings. Thanks for the help Neotko :):)

 

Debugging something like that can be a pain in the ass indeed. I hope that fixes it

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Hello, I'm disassemble the XY movement. Before install the new shafts I wanted to check how much the old ones were bent. So I made them rotate (in place) on the buildplate glass and checking the contact area and...SURPRISE! They are not bent! I tried it on two different plates, in different position, with and without bearings as you done in one your video.

At the moment I'm really confused.

I noticed instead that, a flanged bearing has some play in its hole on the back plate, exactly one that hold the shaft that seemed bent.

Is it possible that this was the cause? I don't know.

Now I will insert some ptfe seal tape around the bearing and after I will reassembled all, I will see if something will be improved.

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