Learning about CNC drives

[Bobbyr70]

Ok, I want to build my own cnc plasma and router table.
I have a hundred questions, hoping some one can guide me through the process.

#1)
I have seen a complete electronics package for around 2000 it includes
motors connectors drives, power supplies, and a manual controler box for 3 axis.

Could I build one for less?
I'm not an electronics tech but I have a good understanding of general electrical components and computers. I have changed out cards and I have flipped a few dip switches.

Another question is around calibration and gearing. I was looking at using gear rack and pinions as an option for driving the carriages. Is there a desired calculation for ratios that are more desireable for the drives? or are they just aobut infinitely adjustable?
What are the pros and cons of gear and pinion mechanical drives versus acme screws or ball screws?

[Al_The_Man]

Originally Posted by Bobbyr70 Ok, I want to build my own cnc plasma and router table.

I trust you mean one of each and not a combined one?

Originally Posted by Bobbyr70 Another question is around calibration and gearing. I was looking at using gear rack and pinions as an option for driving the carriages. Is there a desired calculation for ratios that are more desireable for the drives? or are they just aobut infinitely adjustable? What are the pros and cons of gear and pinion mechanical drives versus acme screws or ball screws?

Look at some of the free servo/stepper sizing programs like Kollmorgen etc , almost every servo/stepper motor manuf. has one.
Usually the type of drive is dictated by the size of the table.
Gearing allows the economical sizing of motor & drive unit, but the top speed of the motor and the required max feed rate generally governs the max. gearing ratio.
Al.

[Bobbyr70]

I did mean one capable of both applications.
It would require quite a change over to remove the cutting table slatts and placing either a vac table or some type of clamping setup. I can see the two not being very compatable. I know just how messy a plasma table gets.
Thanks for the information. I knew about the gain of torque for the drive motors but forgot about the speed loss issue. I have quite a lot of home work to do before I start.
Is there any better servo motors or controlers I should be looking for? My thoughts were to look at something like nema 34 motors maybe 60Vdc brush type with encoders. Maybe gecko drives? What kinds of power supplies should I use? If I choose a power supply should I just get one that puts out only 60v max? or maybe a larger one so it doesn't have to work so hard? and how about anything else one would need to complete this project? Any help will be deeply appreciated. Bob

[ger21]

You can get motors here that will work with Gecko drives.
http://www.kelinginc.net/ServoMotor.html You should be able to get 3 Geckos, motors and a power supply for much less than $2K.