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Bad Print - Strange Layer Shifting & Inconsistencies  

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Nathan Corn
(@nathan-corn)
New Member
Bad Print - Strange Layer Shifting & Inconsistencies

I've had a number of really good prints. However, when I try to print a couple of eggs from thingiverse I get some very strange results. I get what looks to be layer shifting and really wavy side walls. The top and bottom of the print seem to be perfect. The middle part is very strange. I've attached a number of pictures of the results. I printed a different egg and it worked fine. It is a different pattern entirely but printed with only two small layer shifts. These wavy ones seem to have large issues.

Veröffentlicht : 09/10/2018 2:53 am
Nathan Corn
(@nathan-corn)
New Member
Themenstarter answered:
Re: Bad Print - Strange Layer Shifting & Inconsistencies

Some additional pictures of the failed print.

Veröffentlicht : 09/10/2018 2:54 am
thrawn86
(@thrawn86)
Honorable Member
Re: Bad Print - Strange Layer Shifting & Inconsistencies


It is a different pattern entirely but printed with only two small layer shifts. These wavy ones seem to have large issues.

layer shift is one of two things, either one of your pulleys is skipping teeth occasionally or a software issue like what used to happen when printing tethered to usb.

if you're not already: try the newest firmware, make sure your drive pulley set screws are tight for x and y, and see if you have the same issue printing from sdcard.

you may also have some cooling issues, that geometry doesn't allow a lot of airflow in some places

Veröffentlicht : 09/10/2018 5:00 am
Nathan Corn
(@nathan-corn)
New Member
Themenstarter answered:
Re: Bad Print - Strange Layer Shifting & Inconsistencies

Thanks for the reply. The print definitely seems like a software issue when I look at it. I am currently reprinting one of the eggs with the latest firmware. It is only 21% in but it seems to be printing perfectly above layers where the other print started going wrong. I will post back when the print finishes.

Veröffentlicht : 09/10/2018 5:11 am
Nathan Corn
(@nathan-corn)
New Member
Themenstarter answered:
Re: Bad Print - Strange Layer Shifting & Inconsistencies

Looks like updating the firmware fixed my issue. Prints are coming out much better.

Veröffentlicht : 15/10/2018 2:27 am
ben.g16
(@ben-g16)
Estimable Member
Re: Bad Print - Strange Layer Shifting & Inconsistencies

I am having a similar problem with ragged vertical walls. I think I have the latest firmware update (how can you tell?). I adjusted the belt tensions (new mid 2018 MK3). It didn’t help. Then I thought the problem might be with the Slic3r, rounding off layer edges, so I spent a whole day redrawing a complicated object to clean up all edges. No improvement.

Today, I got a big horizontal line through my print. I am prototyping a medical device and can't have it looking like a $200 printer.

Veröffentlicht : 09/01/2019 2:46 am
bobstro
(@bobstro)
Illustrious Member
Re: Bad Print - Strange Layer Shifting & Inconsistencies


I am having a similar problem with ragged vertical walls. I think I have the latest firmware update (how can you tell?).
Go to the Support menu using the front knob on the printer and it will tell you the firmware version.

[...] Today, I got a big horizontal line through my print. I am prototyping a medical device and can't have it looking like a $200 printer.
That can be caused by a variety of factors. Notice that the external shifts correspond to the flat inner surface.

The first thing I'd try is simply slowing down the print. Use the knob at front to dial speed way back to 50% and see if the shift persists.

If you haven't already, consider doing some calibration of your extrusion multiplier. Excessive filament may be piling up on those transition layers.

You can also try different extrusion widths or nozzles.

Finally, it's hard to tell from the pic, but are you having a bit of warping at the front corner nearest the camera? It looks like the print lifted slightly.

If you'd care to provide a link to the STL, we may be able to tell you more.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Veröffentlicht : 14/03/2019 1:49 pm
vintagepc
(@vintagepc)
Mitglied
Re: Bad Print - Strange Layer Shifting & Inconsistencies


Finally, it's hard to tell from the pic, but are you having a bit of warping at the front corner nearest the camera? It looks like the print lifted slightly.

That is probably the culprit; notice the line gets worse the closer you get to the lifting corner.

Veröffentlicht : 14/03/2019 2:03 pm
Bunny Science
(@bunny-science)
Noble Member
Re: Bad Print - Strange Layer Shifting & Inconsistencies

I'm afraid OP's problem only coincidentally got better with a firmware update. The character of layer shift matches a loose drive pulley. It is limited in distance, reverts back to normal position, and recurs with varying degree of shift. I think the firmware update coincides with the pulley happening to jam itself into a metastable position. It will remain OK for a while, but break loose again.

Veröffentlicht : 15/03/2019 6:38 am
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(@)
Illustrious Member
Re: Bad Print - Strange Layer Shifting & Inconsistencies

@Ben - Vote #3 on corner lift == layer bulge.

As for the egg, it does look like a loose something; or a sticking something.

As in all cases: disable the filament sensor and try again. The filament sensor seems to exacerbate or cause a problem with the printer losing track of where it is. The FS routines clear an interrupt flag I suspect shouldn't be cleared the way whoever wrote the code is doing it. I might be wrong, but too many people have issues go away when the sensor is disabled.

Veröffentlicht : 15/03/2019 6:59 am
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