Re: [CAD_CAM_EDM_DRO] EMC Acceleration

Tom Hubin wrote:

>Jon Elson wrote:
>
>
>
>>I've always felt the default values were very high. In
>>inches, turn it
>>down to about 3 to start with, and listen for the acceleration ramp.
>>You should
>>definitely hear the ramping up and down with that setting. (For mm, try
>>50.)
>>
>>
>
>I usually allow a full second to ramp up to the max speed of 20 inches
>per minute. That is 20ipm/sec or about 0.333 inches per second squared
>or about 8.4 mm per second squared. This allows a definite sound as it
>accelerates over a 1 second interval.
>
>

Interesting, I go the other way on acceleration for my Taig mill running
from TurboCNC. I have the acceleration up around 200,000Hz with 1/4
stepping, 20tpi screws, 1.8deg steppers and a rapid speed of about
75ipm, start speed of 0.19ipm (50hz). I think thats about 12.5ipm per
second acceleration. Rapid speed is reached in 1/10th of a second.

>FYI, if 1 second to accelerate is not a problem and I am impatient I
>might set it to a higher value but I have found little gain by doing so.
>1 second to full speed is my rule of thumb for my Sherline mill.
>
>

I guess I'm impatient :) Since TurboCNC doesn't yet have constant
velocity when I run with low accelerations anything with lots of short
lines spends more time changing speed than it does at the specified
cutting speed. This is tedious when prototyping in foam since I can run
at 50ipm for that, and irritating when I want a somewhat consistant
surface finish on aluminium parts.

Dave