Need to mill 16 Gauge 0.060" and 0.09" Aluminum sheet - Advice?

[Reddinr]

I have not done this in quite a while and never have I done it well. I need to mill holes, slots etc. into aluminum enclosure pieces. 6061-T6 I think. For most of the cut-outs I could use a 1/4" end mill but some will require 1/8". I would rather just use the 1/8" for all cuts. I have a mill I converted to CNC that I plan to use. It does a great job on the usual thicker materials. Are there special end-mills that work well in thin stock? Special techniques? Feeds and speeds? One company that does front panels says they use >10000 RPM with 1/8" mills. That seems fast but what do I know? I can solidly mount a fast spindle to my mill if needed to make quality cuts. Anyone have experience with this type of thing?

 

[dlane]

How big are the parts/ panel ?

 

[Robert LaLonde]

Alu-Power 3 flute works pretty good.

Match the speeds and feeds. 3600 or 24000 is possible. Just match the feed rate and rpm.

Big problem with thin stuff is tearing and flexing. I like to glue it to a sacrificial backer but its not always necessary. You can screw it down through screw holes, parts that will be removed, etc. Leave holding tabs you can remove easily by hand later. Lots of ways to secure it.

6061-T6 cuts much nicer than 5052, but some metals yards stock 5052 sheet stock.

 

[pdentrem]

I used hot glue spread onto a backing board, G10 laminate, heated the plate and pressed it down to get a full contact. Once cooled I set it up to be flat. I was using 0.060” end mill at 24000 rpm 30 ipm feed. Worked just fine and once done reheat the plate to get it off the backing board. I don’t have a photo handy but is part of the digital camera back mounting system that is shown in one of the folder on my website pierresplace.ca.

 

[Reddinr]

Sorry I dropped off the thread. My internet was down until now. The panels are about 16.5" x 18". Holes will vary from drilled holes ~.156" to maybe 3" x .375" rectangles. Should I use coolant or wd40 or something? I don't have flood or mist set up but I can hold a can of WD40 for the 5-10 minute jobs. I was thinking of a wood backer with depressions routed out at the cut-outs. G10 is pretty tough on end mills, isn't it? Thanks for all the help so far.

 

[Robert LaLonde]

Flood coolant is best IMO, but oil on the part (that thin just brush on once on the cut areas) and an air blast to blow chips clear to reduce re-cutting should be ok. WD40 does work, but I am not a big fan. If you want cheap then automatic transmission fluid is better in my opinion than WD40. At one time I used flood transmission fluid for hundreds and hundreds of hours of cutting problem free. I just didn't like my shop smelling like a burned up transmission. LOL.

 

[pdentrem]

We use G10 as it is one of the flatter sheet product and yes it does wear end mills! WD40 works due to the Kerosene in the mix. I would definitely wipe it off the machinery afterwards as it tends to make a brown sticky coating in time. Using a wood backer pre cut is a technique that we have used as well. If you use the drilled holes for locating the repeatability is enhanced and as hold down points it will help for sure.

 

[Reddinr]

So I got mixed results. I used a short, 2 flute HSS 1/8" end mill dry cutting with air only on the 6061 parts and it went extremely well. The edges were clean and nearly perfect in every way. Now, the 5052 was a disaster. Using WD40 and then ATF sprayed on while cutting helped but not much. The cutters just loaded up with aluminum "gum" and I ended up breaking a couple of the end mills. I tried varying the feed up and down and speed too. In the end, I did not find the secret sauce for 5052. Unfortunately, the parts I am milling are pre-made enclosure pieces so the material is what it is. For round holes, I ended up using punches. I still have a couple of rectangular openings to go. Any other ideas for 5052?

 

[Reddinr]

I'm thinking about trying this single flute cutter. Anyone have experience with this or similar?

LMT Onsrud 63-610 Solid Carbide Upcut Spiral O Flute Cutting Tool, Inch, Uncoated (Bright) Finish, 22 Degree Helix, 1 Flute, 2.0000" Overall Length, 0.1250" Cutting Diameter, 0.2500" Shank Diameter

 

[pdentrem]

There is a thread on cnczone.com, and single fluke with air blast to remove the chips with cutting fluid. It appears getting rid of the heat is the key, flood coolant would likely cure and the single fluke reduces the heat buildup compared to a 2f mill.