I've been using my cnc for over a year, however I'm new to machining 3D objects on my cnc (SCM Pratix S, uses Xilog) and it seems when it's running the cnc speeds up then slows down for every line of code. The reason it seems like that is on flatter areas of the board it moves faster, but on steeper areas it slows down considerably. I've checked the z-axis (or plunge) speeds on aspire and Xilog. I have them set to be the same as the x and y axis on tools and overall settings. Currently we are running a 4x8 foot panel in 3-4 hours with a 1/2 bit. I've seen many posts about people running 4x8 in 1 hour with an inch bit. I feel like I'm doing something wrong and don't know where to look for a solution. Feed and plunge rate is set up as 15 meters/min or 9.8 inches/sec.