Filament "globbing"

[9alfred99]

I am a newbie. and I have a problem. My first print was a Raspberry pi case and it turned out ok. Had "spider webbing", but other wise ok.

I have now designed a part in Freecad, basically a small block with an internal left hand Acme thread. However when printed I could not thread the rod. Ok, I didn't really expect it to, first attempt and I expect a learning curve and changing the drawing dimensions before the rod would thread . So I used a razor saw to slice it open and examine the threads and I noticed there was a glob of PLA half filling the channel in the same place on every thread, I changed some settings in Slic3r layer height, print speeds, etc. and tried again and watched very closely. When the head would position at that point and begin extruding there is a hesitation and I can see the glob appear before the head starts moving and since it goes to the same x, y coordinates to begin the glob gets bigger.

Also, on one corner the same thing happens to a smaller degree.

Using Freecad, Slic3r. pronterface. and 1.75 PLA.

tj

[sthone]

I'm not familiar with Slic3r but look for a setting along the lines of "Extra Restart Distance"

In a nut shell... The software tells the extruder to retract on moves and then to reprime the nozzle the same amount it retracted when it gets to where its going. If it's to much of a prime you will get a glob at the starting point. Adding say a -.2mm to the extra restart distance setting should help with the blobs. (you'll have to play with the number though to get the right setting for your printer.)

[3dPrintingMD]

https://www.simplify3d.com/support/prin ... s-and-zits

[ednisley]

My first print was a Raspberry pi case

If you haven't done so already, read the beginner's guide, then print calibration squares to verify that you've got all the slicing settings set up correctly. It may seem like wasted effort, but you can spend a remarkable amount of time chasing your own tail around complex objects when the fundamental settings like the filament diameter, extrusion multiplier, and initial height aren't quite right...