Extruder skipping steps after the recommended procedure.

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AlanKilian
Prints-a-lot
Posts: 33
Joined: Wed Nov 23, 2016 3:30 pm
Location: Cambridge, MA

Extruder skipping steps after the recommended procedure.

Post by AlanKilian »

I'm interested in calibrating the E-Steps for my extruder and I'm having some problems.

Machine: Rostock Max V3 / RamBo
Firmware revision: 0.92.2
Firmware date: 20170201
Filament: Hatchbox PLA White
Controls: Octoprint

When I set the hot-end to 220C and extrude 100mm of filament using the "Controls" panel on Octoprint, I get less than 100mm extruded.
When I disconnect the upper end of the bowden tube and cut the filament, I get real-real close to 100mm extruded.
Video: First extruding through nozzle, then extruding into air.
https://youtu.be/U2eGTHwOQAo

I chose 220C to run really hot and try and really reduce the pressure required to extrude. I thought that would help, but it does not seem to.

I have done the HE280 loosen two turns, push, tighten two turns several times.
After this extrusion, I heated to 130C and pulled the bowden tube out and I still have a little puck.
It measures 0.7mm thick. Is that too much of a puck?
https://goo.gl/photos/t9NHy5MENnFveCiS6

When printing, I'm hearing the stepper motor go "Clunk".

I've tried going all the way to 220C and I still get the clunk once in a while.

I've used a thermocouple to test the hot-end right at the nozzle-to-hot end threads, and I'm getting 220C.
(Or 215C or 200C, whatever I set it to)

I'm printing at 20mm/second and 0.3mm layer height.

The stepper motor doesn't really get warm which is unusual in my stepper motor experience.
Do I need to increase the extruder stepper motor current in the firmware?

And ideas on what I can try?

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thingismith
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Posts: 68
Joined: Sat Apr 08, 2017 7:45 pm

Re: Extruder skipping steps after the recommended procedure.

Post by thingismith »

To make sure you're getting the right esteps, you'll need to measure the length of the filament before it extrudes into the hotend, I recommend taking the tube out of the HE (hotend) and measure it there. I find that the recommended value is usually correct.

It's normal for there to be resistance when it goes through the HE. To make sure the right amount of filament is coming through, I recommend following 626pilots calibration method viewtopic.php?f=36&t=10081, particularly the first step. You'll be altering the extrusion multiplier in your slicer program, which alters the speed of the extruder from the original estep speed. Micrometers work best on this test.

There are different values for the extrusion multiplier because there are different resistances by the type of filament material you're using, and the size of your nozzle. Heat is a factor, but it should be set at what you think helps give your print best adhesion and controlled positioning (like bridging, for instance). Happy printing!

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