Wednesday, December 30, 2015

Milling Time Calculations

The program that I wrote for generating gCode to excavate material: I added some code to figure out how long it would take.  For every operation I know how many inches the mill is moving and the feed rate.  Knowing when to return to the mill is a great advantage.  So I tested it last night.  Th program computed 23 minutes to do the operations.  t actually took more like 26 minutes.  My guess is that while LinuxCNC lets me set feed rates as high as 100 in/min, the Sherline mill may not actually move that fast, making the calculations bogus.  I guess today I will measure to see what the actual maximum speed is.  Actual max speed is 20 in/min.


  1. Does your program account for an acceleration and deceleration ramp on each of the machine's axes? Each axis might even have it's own ramp, having differing amounts of mass to move (or different size motors).

  2. While you're taking measurements, how about putting a 26/23 fudge factor into the calculation and monitor the result?