My machine is cutting aluminum!!!!

[ilya]

Finally it's done! I've cut my first front panel with the DIY CNC machine!!!
No engraving yet (I've got no bits), but otherwise everything is perfect! Here are some videos:





There are machine marks on the flat areas, but I don't have boring heads so these flats were machined with the 3mm endmill. I wonder if it's possible to avoid them (but still using the 3mm endmill).

Now, the next step is engraving. After that I'm going to test my machine on a steel enclosure and see how it works out!

I want to thank Ahren from cncrouterparts.com and Nate from finelineautomation.com for their help and cooperation. And I also thank everybody who helped me with the ideas on this forum.

[stevespo]

Ilya, that is great work!

Can you post your feedrate, depth of cut, stepover, spindle speed (RPM)? Some amount of tool marks would be expected with a small machine.

You might see an improvement with a lighter depth of cut on the finishing pass, or if you double check your Z axis to be sure it's absolutely perpendicular to the table. A little bit of cutting fluid may also help. Looks pretty good the way it is, but perhaps there is room for improvement.

Steve

[ilya]

Steve,

I'm cutting at approx. 60 IPM, spindle speed is 13000 RPM and depth of roughr cut is 004", finish cuts are 0.002".
I know that recommended feed rate for this tool is around 90 IPM, but I haven't tried this yet.
I'm pretty sure my Z-axis is square in all planes - I've spent a lot of time aligning it.

[stevespo]

That's about what I've been running. I've been doing more like 24,000 RPM and feed rates of 40-90 IPM. Light cuts as well. .010" for roughing, .005" for finish. So, we're both in the same ballpark. Those numbers were for a .250" endmill. I pocketed/profiled some brass recently with a .125" endmill, but the numbers were about the same.

Steve

[garagefela]

Hello ilya,
Firstly congrats on the machine, those panels sure do look "it and a bit"

It seems to me that the reason you are getting a lot of marks on the floors of the pockets are due to the panel vibrating. You can really hear it in the videos quite well. Ultimately vibration hurts everything.

I see it is screwed down at the ends leaving the middle not hard against the table/scrap piece.

No amount of final cuts will really help in situations like this.

Are you able to provide more opportunities for clamping? Either more screw holes or you may have to resort to placing many clamps over the panel and writing Z axis lifts to clear them.
An MDF panel of the same size but with the holes a bit bigger would be a good way to prevent clamp marks/scratches from getting onto the alum panel

Vacuum table would be another way out or double sided tape. Just a few things that most definitely get you a better finish and a much nicer cutting sound with longer lasting tools.


Good luck and you must report back with more videos.

Cheers M

[ilya]

First, I must corect myself. My depths of cut are 0.04" for roughing and 0.02" for finishing. There was one extra "0" that shouldn't have been there.

garagefela,
I think you are right. It's due to vibration. Unfortunately I haven't got any hold-down clamps yet. And they will help for sure. I'm thinking of bolting the long ends with 2-3 pieces of wood along its length. I haven't found any clamps locally...

I'll remachine the flats and do the engraving with more rigid setup, and post some more pics and videos.