MotoGP1199
Posts: 4
Joined: Sun Sep 02, 2018 5:46 am

Blobs and zits finially gone, woohoo

Fri Sep 14, 2018 1:00 am

Thought I would share my experience as I've seen a bunch of blobs and zits threads lately and none really touched on the one thing that finally got rid of my tiny blobs. A combination of retraction, coast, XY speed cut down my blobs big time but I couldn't get rid of them completely. Wipes just seemed to smear and make the blobs longer ( I have it turned off completely and I don't have stringing). I was able to eliminate the stringing moving my XY axis movement speed up to 100mm/s. I started messing with extra restart distance and didn't notice a difference. I started changing EVERYTHING and noticed it getting worse and better but not gone. Finally I figured out that the "Extra restart distance" needed to be a negative number. When I slowed down the print speed I could actually see the nozzle pause to add more filament before it started moving the hot end. Once I put in a negative number in the blobs and zits are gone. I do not see them at all. I finally settled on a -0.2 and everything looks great. My tips are to slow down the print speed and really watch to see WHEN and what is happening. At full speed I was guessing and making it worse. Also the negative number on the extra start distance will allow the hot end to move(and use the ooze to say) before it starts extruding. What I noticed is that when I would start a new layer it would extrude a little before(or as) it started to move and would make a blob.

SweHogelid
Posts: 5
Joined: Wed Aug 03, 2016 7:01 am

Re: Blobs and zits finially gone, woohoo

Sat Sep 15, 2018 10:46 am

Sorry, I made an misstake.

Cheers!

wirlybird
Posts: 826
Joined: Sun Jul 17, 2016 12:32 pm

Re: Blobs and zits finially gone, woohoo

Mon Sep 17, 2018 6:09 am

A negative restart can help out but everything has an action/reaction. I found that although a negative restart did help in some areas, one area I found an issue develop was when it printed very small detail areas where there was minimal extrusion to begin with. What happened was the small amount of negative restart was enough to cause a little lag in the extrusion start and make an under extrusion situation in the small areas.

An interesting feature could be to have an additional option to not use restart if the extrusion length is below a preset distance. Kind of like the minimum retraction distance setting.

Anyway, just something to watch for if you see some odd results.

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