Temp crash of hot end / PID tuning

Hello everyone!

I've got an issue with my hotend and extruder. I was printing PLA just fine and ran out. So I switched over to ABS and ran into some trouble.

The Setup:
Wade's Extruder
J-head Mk IV-B
White 3mm ABS from 3dprinterstuff.com

In order of occurence:

1. Remove PLA and insert ABS.
2. Test extrude until ABS flows, extrude additional 5mm
3. Hobbed bolt ate through filament. Remove filament, cut and re-insert. Tighten springs until fully compressed. Extrude 5mm ABS from hotend
4. Print in ABS. ABS stops flowing after 3rd layer. Repeat #3.
5. Ensure that filament spool is freely turning.
6. Repeat # 4.
7. Open extruder and clean out hobbed bolt, removing chunks of filament from hobbed bolt grooves and extruder internals. Reassemble and re-insert filament. Extrude 5mm of ABS from hotend.
8. Repeat # 4.
9. Tear down extruder and hotend. Clean and reassemble.
10. Repeat #4.

The springs I've got on the extruder can deliver 10.58 lbs at full compression. They are stiff enough to visibly squash the filament after passing the hobbed bolt, so driving it into the hotend isn't a problem.

So around step 8 I noticed that the temperature of the hotend was crashing to around 185C from 230C. So I'm thinking this is a firmware issue, specifically the PID settings in Sprinter. Or is it the speed of extrusion - forcing too much cold filament through the hotend too quickly? Maybe both. The first layer goes down beautifully, but subsequent layers that are printed faster are the ones having issues.

Any ideas for better Kp, Ki, Kd settings? Mine are at default: 2560, 64, 4096

Or am I going in the wrong direction completely?

Thanks!

Matt

Look for a temperature change in your g-code. Looks like it might have been generated for PLA.

---

[www.hydraraptor.blogspot.com]

And that's exactly where the problem seems to be. My Slic3r settings were off. Firing up the machine for a print now.

Much better. I'm still new to this - day 9 of printing. Thanks a million!