Extruder performance - can it be measured?

ttsalo Wrote:
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> I was thinking of doing it with custom generated
> G-code, with a sequence of constant speed moves on
> each line, alternating with extruder on and off.

Could you device a simple gcode test for that? I'll be glad to run it and compare results.
If we knew or had decided what we need to measure then it would be easier to see how a specific test helps.

EDIT:

To draw the flow vs. temperature graph I extrude much filament in the air, e.g. 200mm of 1.7mm filament, and watch for missing steps. That same could be done on the bed with some custom gcode and measure the exact length where the stepper started missing steps. From that we may be able to deduce some more useful information.

Edited 1 time(s). Last edit at 07/16/2012 04:53PM by dzach.

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3D extruder performance tests
dzach's ORDbot Hadron build

I just stumbled on this excellent description of the extrusion process by Repetier.

It explains much of what I've been seeing in may tests and the photos posted earlier in the thread. I haven't read the whole of it yet but I think it is worth mentioning.

EDIT:

It looks like I've been trying to re-invent the wheel. Repetier-Host already has a similar test incorporated and it is a custom written gcode.

Edited 1 time(s). Last edit at 07/16/2012 05:04PM by dzach.

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3D extruder performance tests
dzach's ORDbot Hadron build

Thanks for posting the video; I'm still working on my code (a bit rusty with the python, heh heh). I'll post again as soon as I get some sort of result.

billyzelsnack Wrote:
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> Is the part you printed above seem nice and
> strong?

I got a little more confident with my thermistor today, after comparing it with a thermocouple and doing a boiling water test:

Water boils at 98°C due to the altitude of my location.

So now I can post the temperatures I used for the performance tests without risking making a fool of myself.

@300mm/s - 290°C
@150mm/s - 260°C
@80mm/s - 240°C
@24mm/s - 220°C (small parts - 9mm dia. max, not the performance test)

The parts would not de-laminate and would require significant force to break by hand, I don't have the means to measure the force required. The plastic bonds really well at these temperatures.

These are not optimum temperatures, just an indication of what is necessary to run a successful test with my extruder at those speeds. The hotend is an all metal one, there is no plastic on it except for the thermistor wire jacket (PTFE tape) and the heater wire jacket (a high temperature material).

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3D extruder performance tests
dzach's ORDbot Hadron build