CNC Router cutting Aluminum

[2Gs]

I would like to build a DIY cnc router for cutting wood and up to 1/6" Aluminum,does anyone have any suggestions as to what I would need for this project. Also the best place to aquire the necessary parts. There is a CNC router table on ebay that looks pretty nice style wise http://cgi.ebay.com/ws/eBayISAPI.dll...831826908&rd=1 price wise seems linda high to me for what you get. Thanks Greg

[ger21]

Start reading the messages in this forum, and the project log. there are a lot of ways to do it. How big do you want it to be? Are you just going to cut sheet goods? What is your budget? Good places to buy stuff are:

Ebay - THK rails, steppers
McMaster-Carr http://www.mcmaster.com Just about anything you could imagine.
MSC http://www.mscdirect.com Similar to above

http://www.geckodrive.com - drives
http://www.xylotex.com - drives

That Ebay router doesn't really seem like that bad a price. To do that yourself you'd probably have close to $500 and a lot of time into it.

[Cold Fusion]

Just to give you a rough idea of what's possible,

My machine costs $1300. It uses ground ball screws, thk rails, steppers, and a Porter Cable 1 3/4 HP router. It will hold .002 in 1 inch of aluminum! It did take almost 7 months of searching for good deals but it was worth it.

[2Gs]

I was thinking somewhere in the range of a 24-42 x 12-18. Budget wise I was thinking around 850.00, I have been reading some posts here about homemade cnc routers and it seems as though some are building them for less than that. I do like the router on the ebay link provided, just the last one sold just like it for 1225.00 which is why I thought that was kinda high for just structure nothing else. What I am looking to cut are airplane parts ( r/c ) the reason I put aluminum in the topic was to also cut parts for an all aluminum airplane ( r/c ). I thought if I scrounged for the aluminum to build the machine I could build it cheaper. BTW are ball screws better than lead srews? What tourque steppers motors are needed, basically what would be needed for a machine to cut aluminum. Thanks

[ger21]

I'd recommend around 200oz-in motors. Ball screws are more efficient, but cost a lot more. You can get pretty good acme for a lot less than ballscrews. Most people here make there nuts from Delrin, the cost is usually under $10 for nuts for the whole machine (3). The most commonly used ballscrews here (cheapest) are the 5/8 from McMaster-Carr. I think they run about $1.09 per inch, and $22 each for the nuts.

If you can get aluminum for free or cheap, and get some good deals on ebay, you can build it for less than the one on Ebay. If you're in a hurry, it will cost you more. The trick to getting good deals on Ebay is patience. If you can wait long enough, you'll usually get better deals.

[2Gs]

I am all new to this, never done anything with cnc before. Part of the problem, you mention ebay is I'm not sure what good deals really are for this kinda of equipment, or what would be best. Thank you for the recommendation on the motor size, and ball screw info, I will look for 200oz motors and 5/8 ball screws. What size of aluminum should be used for the structure(1/2). I saw a guy selling a 20mm 5' linear rail and slide unit with 2 bearings installed in it for 69.00, is that a good price. Thanks for the help

[ger21]

Like I said, be patient and you'll save money. Watch Ebay for a while and you'll get an idea of what things typically sell for. If you have a question about an item, put a link to it here so we know exactly what it is.

I didn't say ballscrews are necessarily better. You can get great results with ACME as well, for a lot less money.

My suggestion is to spend a lot of time learning about how these machines work. Try to read all the large build threads in this forum, they have a lot of good information. Having someone else tell you what to buy is not a good idea, imo. Figure out what you want to do with it, and what you'll need. It's OK for people to give you advice, but you really need to know what you're doing before getting started. Don't start buying anything until you really know what you want. Otherwise, you'll be buying things twice and spending a lot more money than you need to. You may have to wait a few months to get started, but you'll be a lot better off in the end.

[kong]

Like Gerry says, read, read, read!
But as for the 20mm rail, if it is unsupported rail, it will probably flex a little too much over a 5' span. It will be ok for 2' or so, but I would wait for a better deal on some supported shafts in that diameter or greater.