I will like to get some help in finding the proper feed rate and RPM when I'm cutting 3d Engrave or prismatic letters. I noticed that I keep getting shutter edges, very sloopy finish edges. There is any tip, trick or formula to avoid these issues?. Someone told me is has to do with the feedrate I'm applying. I particular use these V-Bits on HDU, Sintra or MDF. Anybody who can give me best advise, I will appreciate very much and Thank you for your time.