wirlybird
Posts: 1374
Joined: Sun Jul 17, 2016 1:32 pm

Bad blobbing on small part. Updated

I am having a real issue with a small cylindrical part. Look at the "sawtooth" edge on the right of the part, this is blobbing where a new extrusion starts. I can't get it to stop. I turn off retraction etc and even the preview shows no retraction but it still insists on retracting and then leaving a huge blob. The first several layers are good then it starts with the blobs.
The other issue is that the diameter gets wider when the blobs start. You can see how the sides slope out as they go up for the first part.

I tried a negative restart and that helps but the first layers are then no good. The are like under extruded and will fall off.

I used to be able to print this part fine and now I don't know why it changed. I must have forgotten the combo to get it right.

Another thing that is odd is I set the fill to 100% but the preview shows no fill in between the inner and outer wall. If I up the overlap then it shows the infill.

PLA
190 temp
60 bed

Image
Last edited by wirlybird on Thu Aug 18, 2016 7:24 pm, edited 1 time in total.
CompoundCarl
Posts: 2005
Joined: Wed Aug 05, 2015 7:23 am

Re: Bad blobbing on small part.

The picture is pretty blurry, so it's hard to tell to much from that. But if you turn off retraction on the Extruders tab, then it definitely shouldn't be retracting. When you say it's still retracting, do you actually mean it's just oozing some?
wirlybird
Posts: 1374
Joined: Sun Jul 17, 2016 1:32 pm

Re: Bad blobbing on small part.

CompoundCarl wrote:The picture is pretty blurry, so it's hard to tell to much from that. But if you turn off retraction on the Extruders tab, then it definitely shouldn't be retracting. When you say it's still retracting, do you actually mean it's just oozing some?
I'll try to get a better pic but it's a pretty small part!

I don't believe it's oozing. I can see the end of the extrusion and it looks ok. After the first four to six layers are done, which don't have a problem, then when it starts a new "layer" I can watch it spurt an excess amount of plastic at the beginning of the extrusion. I tried a negative in the restart field of -.2 and that helped but it made the first layers bad like under extruded.

I know it can do this because I made a tone of these things and they were nice, quite remarkable considering the size! I just can't seem to remember the combination that worked! I will try adjusting the temp some also.

You can see in the pic that the first layers appear smaller in diameter and these do not have the blob issue. It's like it gets to a certain height and everything changes.

I appreciate the help.
wirlybird
Posts: 1374
Joined: Sun Jul 17, 2016 1:32 pm

Re: Bad blobbing on small part. Updated

Here is a better pic of my issues.

1. The blobs on the side. This is where each new layer starts. I can watch it extrude an excess of plastic.

2. At the bottom, the diameter is less (no blobs either) and as you can see it widens going up and this is where the blobs start. I don't know why the first layers are undersized.



Image
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dkightley
Posts: 2405
Joined: Tue Mar 10, 2015 4:09 pm

Re: Bad blobbing on small part. Updated

To get some suggestions as to what settings to adjust, we need to see what your current settings are. Can you attach a factory file for this part and it's profile.

File menu====>Save factory file

I'm not going to be online much in the next few days, so I'm not going to be able to assist - but there's others who can step in and help.....
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net
wirlybird
Posts: 1374
Joined: Sun Jul 17, 2016 1:32 pm

Re: Bad blobbing on small part. Updated

Factory File
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202020.factory
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