My last post I questioned feeds, speeds, etc in an effort to reduce machine times. Since then I have been using Inventor HSM (HSMWorks) and HSMAdvisor to set my cutting parameters and it has helped alot. Now I'm looking to bump up my rapids. If I remember correctly My X and Y axes will do over 300IPM but I could only get up to 145IPM on the Z axis before stalling on the way up. Going off the 'find max speed before stalling and then half that for a reliable speed' I set the z axis just under at 65IPM max.

I am pretty sure I have seen references to z axis speeds of 150IPM for rapids during operations. I wouldn't mind getting up to just 100IPM. Maybe there is something easy I could do such as scrape the ways, or bearing upgrade. I had a couple of other Ideas also.

Replace the 570oz Nema 23 with a 907 or 1200 nema 34.
Belt drive the Z axis with some reduction keep the nema 23.

So I guess Im wondering if that 150IPM is something I am imagining, and whats the best way to get there?
Is that halving of the Max speed before stall the best method?
What are your rapids, and what did you do to get that high?