newbie and student seeking help

[jm0825]

I am a newbie seeking some help. I am an older student who has returned to school to get his AAS in electronics. Next semester begins after Labor Day and I will be doing a capstone project. I am starting now because of the complexity of what I want to do. I would like to build from scratch a 3 axis 24in x 24in CNC table with a small router (3in dia spindle if one is made) something with a 1/4in collet.

I am not expected to design the electronics but to use existing designs and build them then make sure it works. I read a lot of info and it is a lot to digest.

To minimize expenses (remember I am a student; so not a lot of cash). I am trying to build something of quality that I can keep and use without have to donate my left arm.

Here are my thoughts so far as to what I would like to use but would like guidance so I don't over or under kill it. (best bang for the buck)

Stepper motors(500steps/rev). I have no idea how much torque I will need.
3/4in rock hard maple plywood for most of the table components
Thomson bearings ,rails, and ball lead screws

I will need to build power supply and motor drivers and interface for the computer. I can create my own pcb board. I am looking for schematics and or circuits that are proven and will work. When this has been built I plan on using it to do pcb boards and small wood working projects.

I do happen to have a friend who has a cabinet shop who owes me some favors and he has an industrial CNC router and has offered to cut any of the parts out. This will ensure that the parts are square and true.

As part of this project I must document and explain theory of operation for each of the electronic components. Provide a bill of materials etc, and make a final presentation showing an operational project. Since I am documenting everything anyway I would be very happy to share everything when I am done.

I am not expecting anyone to do my project for me but I am asking for mentoring and any help in putting all the information together so I can build it right the first time. The semester is only 12 weeks long and I have other classes as well. So I have limited time to put this project together and make it work so I would like to minimize the mistakes before I start.

My sincere thanks for any help

Jack

[ger21]

Most stepper motors are 200 steps/rev. I've never seen 500??
I'd recommend baltic birch plywood. It's more expensive, but much stronger and flatter, and more stable.

Ballscrews are expensive. Most people building routers use acme screws and anti backlash nuts from www.dumpstercnc.com They work great and will save you a lot of money.

Lots of info on building drives here.

http://pminmo.com/

[jm0825]

Thanks I will research this

[bob^]

Hi mate, this is the schematic for the breakout board, stepper driver, and powersupply that I use.
http://secure.oatleyelectronics.com/...K142notesc.pdf

[jm0825]

Thanks this info looks really good