Re: Commercial CNC vs. Homemade CNC Router

> Date: Thu, 06 Feb 2003 05:07:39 -0000
> From: "asennad <asenna@...>" <asenna@...>
>Subject: Commercial CNC vs. Homemade CNC Router
>
>I wish to produce parts for a watercraft that I am building. It requires
>precisely dilled holes in thin aluminum sheet metal (.016 – .040) for the
>purpose of riveting.

>I would require a machine that would accept 4 x 8 feet sheets.

For a single part or set of parts, the cost in time and cash to make your own machine will be more than commercial CNC sources.

You have not specified the tolerances for either the hole sizes or the locations. Once you have done that you will be better able to evaluate the cost tradeoffs.

A possible alternative for you would be to mount a drill motor on a Shopbot.

This machine is around $7000 in a kit form for a full sheet size. You assemble the table and do the mechanical tweaking. Figure 1 or 2 maybe as much as 3 man days for assembly and run-in. This machine can be calibrated to hold about .008 inch on hole center locations across a 4 x 8 sheet (How well can you measure it?). It rapids at 180 inches per minute in X & Y, less in Z. It is not really suitable for routing complex contours in Aluminum, but can be used as a plasma table.

This is the least labor intensive do it yourself option that I have seen. It includes all the electronics, motors and wiring harnesses with connectors attached. The stages all bolt together and the assembly requires no power tools. There is little risk that you will invest in equipment that will never be usable, and there is no research and development time (also known as: chucking it all and starting over). ;-)

As far a sourcing for commercial, while it is off topic, try your local yellow pages under Sheet Metal Fabricators
You could also look for a local Shopbotter to do the work. They sometimes will work for the challenge and there are lots of them around. ;-)

http://www.shopbottools.com Check the forum

Best Regards, Fred Smith- IMService

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