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strange problem, always rear part of print inconsisent?  

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Dutch
(@dutch)
Eminent Member
strange problem, always rear part of print inconsisent?

Our Mk3S with MM unit2 want printing unacceptable from one day on the other, out of the blue.

It doesnt matter on which part of the printbed i print, the rear last 10mm is always "bad". I cant think of what can cause this.

 

From all the prints i make, the front left and right are really perfect. The rear is always ugly. Side is looking as the layers are not straight above eachother and look "wavy".

The top looks very unsmooth. The printnozzle also scratches on the print over there, always approx. the last 10 millimeters of the print. The higher it is, the worse it gets.

Tried many things, but i cant think of anything that can cause this.

Its not the whole print, so it cant be spindles, of uneven bed. Print doesnt come up, bottom is sticky and flat.

The rear has "threads" when coled down, you can literally "pull" a "molten wire" print from the rear. I think this is due the printhead whobbling front to back with scratching the bottom. if i wouldn't know better, i'd say the printhead is too low printing the last 10mm of a print, compressing the material too much. But that wouldn't make any sense...

First layer is good.

bearings replaced, same results.

Belts tensioned, same results.

Printing with octoprint or SD same results.

Printed "older" designs that went perfect before, same (bad) results.

 

Anyone?

Posted : 05/03/2023 11:19 pm
Hello
(@hello)
Noble Member
RE: strange problem, always rear part of print inconsisent?

Images of the print may help if you could print 3 of 20 mm by 20 mm box and post pictures of them all then we can see if it happens same place same layer and looks same that normally can help us identify some things 

Thanks 

Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models

Posted : 06/03/2023 7:44 am
Dutch
(@dutch)
Eminent Member
Topic starter answered:
RE: strange problem, always rear part of print inconsisent?

Posted : 06/03/2023 8:26 am
Hello
(@hello)
Noble Member
RE: strange problem, always rear part of print inconsisent?

Picture of hotend and extruder from all sides bottom left right front and underneath please 

@diem yes it is normally caused by draft or incorrect cooling but can be caused by something coming loose or wrongly built hotend.

Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models

Posted : 07/03/2023 2:47 am
Dutch
(@dutch)
Eminent Member
Topic starter answered:
RE: strange problem, always rear part of print inconsisent?

Here are some more images of the print head
https://imgur.com/a/gdxeMBK

Posted : 11/03/2023 10:59 am
Hello
(@hello)
Noble Member
RE: strange problem, always rear part of print inconsisent?

Apart from heat block been very dirty all looks ok please try print 20mmx20mm cube right in middle of the heat bed 

Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models

Posted : 11/03/2023 5:48 pm
Dutch
(@dutch)
Eminent Member
Topic starter answered:
RE: strange problem, always rear part of print inconsisent?

we'll do. Results will be posted.

 

Posted by: @hello

Apart from heat block been very dirty all looks ok please try print 20mmx20mm cube right in middle of the heat bed 

 

Posted : 11/03/2023 6:10 pm
Dutch
(@dutch)
Eminent Member
Topic starter answered:
RE: strange problem, always rear part of print inconsisent?

three blocks: 10mm 20mm and 30mm

Especially the 30mm is clearly visible, but all blocks have the same issue. Printed in the center of the bed at the sane time, next to each other.

 

https://imgur.com/a/1Fp8FKp

 

Posted : 12/03/2023 10:23 am
Hello
(@hello)
Noble Member
RE: strange problem, always rear part of print inconsisent?

Sorry for late response it seems something is unlevel can you please print those 3 blocks 1 at a time in the middle please 

Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models

Posted : 14/03/2023 6:07 pm
Crab
 Crab
(@crab)
Reputable Member
RE: strange problem, always rear part of print inconsisent?

I have a similar problem when printing spheres on mine.. mine is caused by inconsistent cooling.. the front cools better than the back.. I think some of that is built in.. but you can check your fan and shroud to see how the air flow is.. but likely the issue is non-symmetric cooling. 

Posted : 14/03/2023 8:16 pm
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