my feed rate is pretty high around 200 during roughing, but during finishing the feed rate slows down to around 60 70, i see that mach 3 isnt processing the lines fast enough and the finishing pass is really slow. is their a setting where you can change how much lines of gcode it can process in a second? is it subject to computer speed or kernal speed? thanks in advance
Typically, it's the acceleration rate of your machine that limits velocity during 3D cutting. The faster it can accelerate, then the faster it can follow the toolpath.
There's a lookahead setting that you might want to increase but I don't know it it will help.
Yes... I had successfully changed the LookAhead and increased my feedrates, as well as smoothed out machine movements. As Gerry eluded to, your accel settings will also affect your machine times, but you must be careful to not push things too hard with steppers. Ultimately it's a combination of CV settings and LookAhead that wil optimize your 3D speeds. I have heard of some who had details "lost" or smoothed due to CV angle settings and LookAhead, so you may want to save different Mach3 profiles depending on what youu are carving. Obviously this "smoothing" may be beneficial depending on what you are machining. I posted a thread on this particular subject a while back, as most 3D CAD will typically use many small line segments to interpolate a curve, and if your LookAhead is too low, youu'll have constant accel/decel depending on the tolerance you set on your CAM (the tighter the tolerance, generally the more line segments....)
The best article on these settings were written by David Bloomfield. I would suggest reading through this article before making any changes.