Linear motion drives for CNC router

v Ball screw (problems: backlash, not self –locking, expensive)

v Lead screws/power screws/translations screws: (efficiency 25%-70% , higher pitches result in higher efficiencies)

§  Acme screw (cheap, small/no backlash. Small pitch and slow speeds)

§  Square screw (most efficient, least friction, most difficult to machine, and most expensive)

§  Metric V thread (lowest efficiency)

v Rack and pinion

The following table shows a quick comparison between lead screw and ball screw as they are almost used in hobby CNC routers

Point of view	Lead screw	Ball screw
Efficiency
Linear speed	Slow	High
Self-locking	In most	No
Cost	Relatively cheap	Expensive
Manufacturing	Easier	Difficult
Backlash	Small	Large
Backlash compensation	Using Anti-backlash nut	Using software
Pitch	Small	Large