Cnc PCB drilling machines z axis linear pot

On studying many CNC PCB drilling machines I find that most professional high speed drills with hit rates above 100 drills per minute use a linear potentiometer on the Z axis [drill depth] instead of a encoder/linear scale.

The X & Y axes could have a linear scale or rotary encoder depending on accuracy required and end price.

Is there any advantage of using this potentiometer. The Z axis has to do the most hard work and may retract at speeds of approximatly 10 to 25 metre/minute. Average depth accuracy approximatly 20 to 50 microns.

Look forward to the groups views on this

Byron Damania



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