Need a little help with choosing gear layout

[PhilipFry]

I've recently started working on a project here at work that would use a rack and pinion system. Can you offer some suggestions on how to design a system? In other words, how do you choose your gear size, profile, tooth thickness, number of teeth, etc.

 

[plasgears]

The rack in the system transmits axial force. This is the same force that is projected on the pinion. Knowing the pitch radius you now have the pinion torque. Power is a function of torque x speed. You have to start somewhere, so choose a gear pitch and discover the forces and torques in the system. If the stresses are too high go to coarser pitches. Plot your stress and power results, and the solution will jump off the paper.