CNC Flat Bed Router and Mill

[jjr2001]

Here are a few pictures of my home brew CNC machine. I have milled 1/2" and 5/8 inch aluminum with it.
I call it a hybrid since it is made with some 8020 aluminum extrusions, industrial linear bearings, aluminum plate, and MDF.
The MDF parts are the gantry horizontal and vertical members and the front and back end members. The MDF started out as
3/4" but all of the mentioned pieces are doubled. They were pinned with 4 quarter inch dowels, drilled for about 70 # 10 screws,
disassembled, and them glued and re-screwed together for a nice 1 1/2" thick piece of "alumamdf".

Costs less and weights less than aluminum plate and easy to work with when all you have is a drill press, table saw, and band saw.
The bed is a bit larger than 32" x 32".
Works pretty well, built a few model planes with it including an F4 Phantom with a 90mm edf.

Cheers, JR

[kvom]

Quite impressive.  What kind of cuts can it manage in 1/2" aluminum?

[jjr2001]

Since I try not to use too much oil (wd40) while cutting aluminum with a 1/8" carbide bit I can cut about .030 deep per pass. (Porter Cable Router with reduced speed)
I have a universal motor speed control that reduces the 20K rpm to about 10K rpm.
About the same with brass. I did mill a brass fly wheel using .025 depth with a 1/8 EM. The flywheel is 3/8" thick and about 3" in diameter.
I have made finish passes of 1/2" thick aluminum plate full depth but only cutting .003" deep for the finish cut.
When drilling (such as for a tooling plate) with multiple holes I will use the 1/8 EM to spiral drill all of the holes and then finish on the drill press to handle all that swarf.
This method gives me accurate layout with the speed of the drill press for completing the project. Spiral drilling the holes to full diameter is slow.

I have a slower spindle that I can use with larger end mills but most of the time I just use the Porter Cable Router for most work.

Cheers, JR

[kvom]

20K rpm ought to be fine for aluminum as long as you keep the feed high enough for a proper chip load.  Lately I've been using trochoidal toolpaths with a full depth of cut on aluminum sheet (1/4 and 3/8 two flute endmills).

[jjr2001]

Thanks Kvom, I still need to do more testing with the larger end mills on this CNC machine. So far I am very happy with the results. Saves a lot of time and it is quite a joy to use.
The capabilities are amazing. It started out to just cut aircraft plywood and 6mm depron foam but it is able to do so much more.

Cheers, JR