[vinybinder]

Hello everyone,

I'm seriously thinking of building my own milling machine.
i made some research on the web as well as in CNC Zone, but since english is not my language, i may not enter "good enough" keywords or fully understand all of your discussions.

So here what i ended with:

Made to mill aluminium and steel (it would be really a dream if it would be able to handle tool steel, even if i would need to make more thinner passes).

1). DIMENSIONS:
X: 6.5 feet
Y: 3.25 feet
Z: 2 feet
Note: if it has to mill some hard steel (or even mild steel), i dont think it will be done on parts more than 1'*1' big. Big X and Y axis are there for when i need to machine soft materials (clay, softwood, etc). Aluminium would maybe be milled on a 2'*2' basis.

2). FEATURES:
Ballscrews (thought of 1.5" diameter) on all axis.
Linear ball guides.
(For screws and guide, i took that site as an example: http://www.screwtech.cn
NEMA 42 steppers.
10000 RPM 4Kw spindle (BUT speed reduced by belt).
0,0004 inche precision.
Business end not bigger than 7/8 inch.
Speed of machining: the fastest possible, but not especially ligthning fast.

3). ABOUT ME:
I can weld, machine (lathe and milling machine), CAD drawing. I have access to sheet metal brake (up to 1/2 inch thick steel), laser cutting (up to 3/4 inch thick steel), , and cnc milling. The weight of the all machine is not a problem.
In other words, i can build everything I need to reach my goal.

4). MY QUESTION:
Does all that make sense to you? Every comment, suggestion, idea, etc is really welcome. This is not a "one day dream" so i would really appreciate your help. Thank you all, have a good one.

[keebler303]

Add up the prices for all of the components you will need, then double that number to get what it will actually cost. I'll bet that 1.5" ballscrews and 35mm rails are not gonna come cheap. You also probably want to re-evaluate your choice of spindle, its not only about speed, you also need rigidity. After I had spent this much money on a machine, I wouldn't be using stepper motors, I'd use AC servos.

After all this, plus your time (lots) it would be cheaper to buy a used machine and happily start cutting parts. You would also have the advantage of professional components, a tool changer, support from other users of similar machines, etc.

If the journey is the destination, then go for it, but if making a machine is just a means to an end, I would be looking at used equipment.

Good Luck
Matt

[vinybinder]

Hey Matt,

Since u did not tell me "no way this will work" i bet i'm not so wrong with that setup. I'll have a deeper look at servos.

And yeah, the fact of building it from blank sheet of paper to usable machine is the first goal. I'll put it to work very often tho...
I can't afford buying a used machine and modify it, i'd rather spend all that money in 1-2 years in a machine i'll be proud (hopefully) of cos i made it.

For the spindle as i mentioned it, the speed will be reduced a bit thx to a belt drive system. Rigidity should not be a problem since i'll build everything strong enough in sheet metal (some kind of skull actually), and filling the gaps with some stone polymer. I cant cast my own stuff so thats what i thought about: sheet metal (thick enough)+ polymer.

Thank you for your answer :cheers:

[keebler303]

You haven't given enough detail for me to say "no way it will work!"

I wouldn't recommend a filled sheetmetal approach. How will you attach your components together? How do you make your pieces flat after filling with polymer concrete? I would utilize that laser to make a frame from steel plate, then stress relieve every piece prior to final machining. If you have access to equipment large enough, it is probably the best way. I think you will be setting yourself up for failure on a machine that big unless you know good and well how you will complete every step.

I can almost guarantee you will spend more money over 2 years building it than if you just bought a used machine.

Start getting prices on your components and add them up. I'd say its impossible to meet your requirements with less than $10,000 and $20,000 is probably much more realistic. You can buy a pretty nice used machine for that.

Matt