Plc or mach 3 cnc

what are the plus and minuses to using a plc or cnc ,,im very partial to direct logic plc's ... can't i do everything a cnc say, mach3 can do, with a plc the reason i ask is i've been asked to build a hand polisher with 3 moving heads and have been told that CNC would be the only possible way to-do it..well i disagreed and have been put on the spot to prove it....thanks Mer..

Here you can find an integrated solution (Twincat PLC+CNC) from Beckhoff. Twincat is a CoDeSys derivate. I haven't used it myself.

http://www.beckhoff.com/english.asp?twincat/twincat_cnc.htm

What are the specs for your system? What kind of coordination do you need between the three axes? How about G-code programming? A PLC-based motion controller can probably move an axis from point A to point B just as quickly and accurately as a CNC. A CNC will do a better job of managing multiple axes than a PLC. Most PLCs can't handle G-codes.

PLC vs CNC

I'll have to echo what Steve Bailey said: CNC will do better with multiple axes than a PLC, and will have more versatility and precision in terms of working with programs in G-Code to turn out items to greater accuracy.

I'm not sure what is meant by "a hand polisher with three moving heads". If this thing has to move precisely under programmed control in more than one axis at a time, spring for a CNC. You might want to look at OpenCNC if the price differential is a real factor - it might cut that price tag down to size for you (but you'll have to do some of the grunt work yourself...)

Automation Direct's gear is great for small projects, and if you have the experience with it, it can do truly amazing things for the money. I hope you're right - it would make another success story for a line of PLC equipment that is often overlooked in the circles I've had to travel in.

Here's hoping all goes well with your project, and that you're not on the spot too severely.

Later On,
D

mer said:

what are the plus and minuses to using a plc or cnc ,,im very partial to direct logic plc's ... can't i do everything a cnc say, mach3 can do, with a plc the reason i ask is i've been asked to build a hand polisher with 3 moving heads and have been told that CNC would be the only possible way to-do it..well i disagreed and have been put on the spot to prove it....thanks Mer..

Click to expand...

I would liken this to the difference of using a wheel-barrel or a dump-truck.