Thumping extruder stepper

Hi everyone,

I know this may be a frequent topic, but I've tried all the suggestions I've seen and it hasn't helped...

I have a Prusa i3 with a freshly installed E3D Volcano heater block and 0.6mm nozzle. I'm trying this as a replacement for the cheap heater block and 0.4mm nozzle it came with, which clogged constantly, oozed, and made stringy extrusions. The (PLA) prints I've been getting with the new setup seem to be working real well - the finish on the sides is really good (can barely see the layers!), and it's not stringy. The only problem that's persisted from the old setup is the 'thumping' coming from the extruder stepper as it misses steps and is forced backward by the filament. I thought this was a byproduct of the clogging with the old nozzle, but apparently not. For the record I'm printing at 185C, so I doubt it's a problem with insufficient melt temperature. I think it's very unlikely that the new nozzle is clogged, since I had the issue right away, and there aren't any other side effects of clogging (stringy extrusions, etc.). I'm wondering if it might be solvable by tweaking the extrusion multiplier, but I don't want to mess with the really nice finish...

Any help would be appreciated!

Thanks,
Ben

Edit: A thumpy print with the new setup just finished, and I just noticed that the outer 2 shells have barely any adhesion to the inner one - they can be pulled away from it easily. Also the side finish got progressively worse as the print progressed - on an upper part, some of the lines are a bit wavy at some spots,and there are some tiny holes and bulges of filament on the side.

Edited 1 time(s). Last edit at 08/15/2016 06:36PM by misterhamin.

I think you need to raise the temp. I have been doing pla more like 195 or 200. Bad adhesion and extruder clicking both could be from the temp being too low.

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Newbie with Folgertech 2020 i3.

+1 on raising the temp. I usually use 200 degrees for PLA.

Don't know why I didn't think to do this before... works real good now, no stringy shells, and only a couple thumps throughout the whole print, but they didn't seem to affect anything. Guess that's just having a cheap printer

Thanks everyone!

Ben

Quote
misterhamin
Don't know why I didn't think to do this before... works real good now, no stringy shells, and only a couple thumps throughout the whole print, but they didn't seem to affect anything. Guess that's just having a cheap printer

Thanks everyone!

Ben

I was experiencing a few thumps here and there with no visible signs, and discovered on one of the machine I could change my extruder steps from 154 to 152 and the thumping stopped. On the other machine, it didn't go away until I changed over to a geared extruder setup.