Start layer blobbing?

[danlad1631]

Newbie here.

I'm using a Mendel90 and attached are some of the problems I'm having. At the start of each new layer it seems to over extrude and leaves a blob and as the head comes round to start the second perimeter and steps inside the outer perimeter, it doesn't join. This is then leaving a very small gap which looks wrong. I've tried changing retraction distance, extra start distance, retraction speed and using wipe, this has made a small improvement on some prints but it's still not great.

I've checked my E steps and they are spot on, so it can't be that. I'm not having this problem with Kisslicer, Skeinforge or Slic3r, it's got to be a settings issue.

How can I solve this? Please help.

[danlad1631]

Any advice would be appreciated??

[MasterFX]

Try to enable the "Coast at End". I had the experience that the blobs are less extreme with 0.2 or 0.4

[danlad1631]

Ok I'll give that a go, but It seems to me like it's over extruding at the start of the layer. Any ideas on what's causing that? Does Coast at end have effect on the start of layer?

[jimc]

Its actually not overextruding since during a rapid jump its not extruding at all. This blob at the start is what is oozing from the nozzle dueing the jump. Its due to the pressure left in the hot end. Coasting stops extruding before the end of a line to relieve pressure. Turn coasting on maybe 1.5mm then the wipe feature maybe 3-5 mm. Turn your extra restart distance to neg -.01 and see if that helps

[danlad1631]

I've tried your suggestion and other peoples but I can't get rid of the blobs. I've been printing a calibration cube and it's better but not as good as it should be. The image attached has been printed with Kisslicer and is much better. I feel like I've tried every possible combination of settings and can't get it right, should it be this hard with a $140 piece of software? I've spent hours upon hours now and think its time to knock S3D on the head.

[BaudR8]

I've tried your suggestion and other peoples but I can't get rid of the blobs. I've been printing a calibration cube and it's better but not as good as it should be. The image attached has been printed with Kisslicer and is much better. I feel like I've tried every possible combination of settings and can't get it right, should it be this hard with a $140 piece of software? I've spent hours upon hours now and think its time to knock S3D on the head.

Do you have a picture of your results from trying the Coast option and/or possibly a picture of the calibration cube from s3d? It does seem like your extrusion rate may be a bit high as well from both pictures you've posted so far.

[danlad1631]

Attached is a print I stopped as the results are not good. The blobs are on all corners. When I watch the print you can see it lays down the inside layer of cube then does a rapid movement to the outside perimeter, the blob is where it then starts that layer. If that makes sense?

[BaudR8]

Attached is a print I stopped as the results are not good. The blobs are on all corners. When I watch the print you can see it lays down the inside layer of cube then does a rapid movement to the outside perimeter, the blob is where it then starts that layer. If that makes sense?

With the coast feature still enabled, you may also try lowering the speed of Default Printing Speed and the X/Y Movement Speed to prevent backlashing during fast printing and rapid moves.

[danlad1631]

Ok, I'll give that a go. I can't understand how kisslicer doesn't give the same results with the same speed settings. Thanks for the help.