I have a Creality Ender 3 Pro.
It has a problem with blobs - NOT the small ones that mar the finish of a print but large, random, print destroying blobs!
I’m printing PETG. Laying down a raft on painters’ blue tape for print stability but even that can produce problems. I can tune the heated bed to get a beautiful, even first layer but it can spit out a big wodge of material which will sit on the surface and harden if I do not stand over it, watching like a hawk and ready to remove the blob by hand or with tweezers.
Obviously it is impractical to watch a print for 14 hours or more (I’m trying to print a large mount for a motor). If the print manages to get several layers high it may spit out a blob that then hardens and atthe next pass the print head is knocked by the hard lump causing a marked layer shift. In extreme cases that can be 10mm or more.
I have tried printing at various temperatures, have retraction enabled, also combing.
Setup tonight is
255 degrees print temp.
Print speed 60mm/s
Combing Mode: ON and set to “Within Infill“
Retraction Distance: 6mm
Retraction Speed: 45mm/s
Maximum Retraction Count: 5
Minimum Extrusion Distance Window: 10mm
Already had two blobs, one of which kicked the x-axis 2mm off line and I’m only at 10% of full print. Fortunately I may be able to still use the resulting object.
One last thought - and it may be the key to this – I’m using PETG from Hobby King …