Setting E-steps for different materials?
December 08, 2012 04:47AM
Hey everybody!

Was previously posting as "Bainesy" but thought I would sign up cos this is looking like a GREAT forum!

Without further ado - my question is:

I've set my E steps for my extruder using the PLA which was supplied with my printer. I've noticed in skeinforge there is a "packing density" setting in the dimension plugin which (from my understanding, please correct me if wrong) accounts for the fact that some materials are softer than others, meaning that the hobbed bolt will dig into the material more and therefore, feeding 50mm of material may only feed 47 or 48mm (depending on conditions)

So - this is great, skeinforge can allow for the difference between materials feeding at different rates.

Now, I'm trying to setup my printer for ABS, so, I mark the filament, feed through 50mm and measure where I've marked - it's only really fed 45mm through...

Question is - is it necessary to tweak the "e-steps" every time you have a different material to print with OR - does this skeinforge "packing density" take care of it in the G code? (obviously using pronterface to "extrude 5mm" sends a command to extrude exactly 5mm which does not work correctly but I'm assuming that in the actual gcode it generates for parts this will be corrected?)

I'd like to have the MOST precise prints possible, I work with CNC machines every day chasing tolerances of .01 - I am up for the hard-yards involved in calibrating this thing as tightly as possible, but I am unsure because my abs prints at this stage are leaving a little to be desired! I'm having a lot of trouble getting inside and outside sizes SPOT ON - and I'm wondering if the e-steps i've setup for PLA are not working for my ABS...

Thanks in advance for any advice!

Cheers ;-)

Re: Setting E-steps for different materials?
December 09, 2012 04:44PM
I'm not sure what the Marlin guru's latest ideas are, but steps per mm is a mechanical constraint. So it shouldn't change unless you change something in the mechanics area (or microstepping).

As different materials can extrude differently, e.g. due to different diameters, there should be some value in your slicing software to compensate for that.

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