Extruder Speed Test

[Chris Muncy]

This is courtesy of Matt (electronrancher) over at the Yahoo Group:

Howdy Folks,

If you read my wiki (build notes) section on converting the ramsey to software control, you may have noticed that I had a limit of 120 in the extruder velocity. That is WAY slower than the extruder can drive, and ended up making quick retraction stuff useless as Mach will clamp high feed rates to whatever the velocity number in motor tuning is.

So I hacked up a quick gcode to test extrusion speed. It incrementally extrudes 1mm of filament at increasing speeds until the user notes the extruder skipping. Each mm has a half second pause so we mere humans can tell them apart.

To use it, copy to a file called extrudertest.gcode or whatever. Next, power up and wait for the device to reach temp. Then, run the gcode and pay attention to where it starts skipping. That's your limit. The ramsey is weaker than easydrive, so I expect it to score lower - which is why I'm not just telling you the exact number (800 for me).

You may have to run a few times, but since it counts in increments of 100, it is easy to count along while watching the extruder gears. It will be obvious when they skip - make note of that point. If you like watching the gcode instead, then just listen for the ever-increasing hum to start clunking.

I suggest backing off two steps. Mine skips at 1000, so I'm using 800 as the "clamp" in motor tuning velocity. Much more awesome than the 120 I had in there before. Feel free to adjust the gcode to finer increments, etc, in order to dial it to the max.

I'm sure I don't need to mention that my extruder is running on the A axis, so replace the A's with your own axis if your setup is different..