System for turning Rotational into Linear movement

[MattyAB]

Hey Everyone,

I want to build a Laser cutter for myself from scratch (sort of). I need some way of turning the rotational energy of the servo into a linear movement. I want something fairly cheap, so nothing to pricey. I thought of the classic Lego style thing, with a gear on the servo, with a 'flat' gear:

I couldn't find anything like this though - is there a specific name for them? Or is there a more efficient and easier way of doing this job?

Thanks!

 

[Nidum]

Called a rack and pinion .

Much easier though to use long screws with nuts .

 

[MattyAB]

Aha thanks.
What do you mean by "long screws with nuts"?

Thanks again!

 

[boneh3ad]

He means a ball screw or a lead screw. They are generally easier to use than a rack and pinion system and have better tolerance and backlash properties. They take in price rather wildly depending on your application and precision requirements.

 

[CWatters]

There is quite a large online community for people building their own CNC machines. Try googling "DIY CNC machine" without quotes and you should be able to find people who have built something similar before, sources for kit etc

 

[David Lewis]

There is also the recirculating ball mechanism, which is a worm and sector gear arrangement with uncaged ball bearings between the worm gear (on the drive shaft) and ball nut rack to reduce wear, friction and backlash. One difference is that rack and pinion is reversible (moving the rack turns the pinion). Worm and pinion gear train is not reversible unless the gear ratio is very low.

I believe you will also need closed loop servo motors to move the cutting head. Both position and speed are fed back to the error detector. The motor slows down as position error goes to zero in order to prevent overshoot.