Need Help!- Newbie ready to Start but has a few questions

[aledford]

After many years of lurking here on the board I am just about ready to take the plunge. I am looking to build a machine capable of cutting 5'X5' Plywood, Acrylic, and 1/4" aluminum. I have a few questions I want to run by the you guys to make sure that I know what i am getting into. First, about me. I am an experienced woodworker and pretty handy. I have a well-equiped shop (but no welding equip or experience). I studied manufacturing in college so I know about CNC but no real practical experience other that some work with automed test equipment. Budget is not the primary driver for this project but itis a consideration. I want to build my own machine mostly because thats how I roll . I'm looking forward to the learning experience as well as having a tool that is well suited to my needs. In the end I will need the machine to be capable of doing prfessional level work(good finish, good accuracy). I intend to use the machine to cut parts and patterns for my woodworking and furniture projects. I also would like to offer prototyping and small production run services as a side business. My current design is to use 72" 3060 from 8020 for the X axis. This will have 4 X 1/4 CRS on to and use the linear bearings from cncrouterparts.com. the Y axis will be 3060 on edge with 7 X 1/4 on the face and the Z axis will be the one that cncrouter parts describes on thier site. I will use NEMA 43 steppers and R&P drive and a 1.5 KW spindle to Start with. I am planning on using Mach 3 software
So my questions are:
1) Back of the napkis estimates tell me that I should be able to do this for $6K. Can some of you moer experienced builders tell me if this is realistic?

2) does the machine I described shoud like it will be capable of meeting my requirements.

3) any suggestions on components that I should go ahead and plan on upgrading from the start

Thanks for any comments/suggestions. I've really enjoyed reading about the build you guys have done and i'm looking forward to joining the diy CNC community

Thanks

Alton

[jsheerin]

I have a similar machine but using screw drive. Nema 42 motors are probably overkill for that type of machine. I'd use N34 which I think Ahren is developing a R&P kit for (maybe this is what you meant but wrote as N43?). I'd say such a machine would be very capable of meeting your requirements.

I'd say your budget could possibly be met. I spent a bit more on mine, but that included a computer, cam software, quite a bit of tooling and some dust collection parts. Realistically you will need all those things as well eventually, but you could save money on the cam software (I bought Visual Mill which was $1k). However you will need larger motor drivers and power supply than what I used (I used N23 motors and a G540) plus a breakout board. That will bump you up in price a bit.

My only suggestions would be to also budget for a dust collector, the bigger the better, and to think about using a larger spindle like a 2.2kW. I haven't used my spindle yet so this is not from first hand experience, but given that you're going with larger motors and the price difference is not that huge, it could be a good idea to go with that up front. Based on others' experiences here, I'd also suggest buying a name brand VFD instead of the ones typically available on ebay from China.