Cutting some 5052 sheet on my router.

Thanks for you guys who offered some help and suggestions here is a video of some of the work. The edge quality came out pretty good much better than the water jet parts. I was running air to keep the chips clear and the MQL mist system. The speed was very slow 10K RPM 40 IPM & .125" cut material is .250" 5052 Al. I did not have any problems with gumming up the bit. I plan to run it a little harder but with the through cuts I was losing quite a bit of vacuum so I could not push it too hard.

Machining some 1/4" 552 AL sheet. - YouTube

Nice job and thanks for the feedback, makes a nice change

I just got done with a good sized job cutting some aluminum on my Komo cnc router, at least it looked like aluminum, nasty, gummy junk. Anyway, I wasn't getting anywhere until I got a new cutter. Someone on here suggested an Onsrud cutter and I ended up getting a 65 series 'super O'. I was cutting a kajillion 2" square holes in 4x10 sheets and it had to have a 1/8" corner rad, so I used the 65-23. It made all the difference, I ran at 10K and 30 ipm. Could have pushed it harder I think, but wanted to be able to walk away from it so left it at that.

:: Super O Router Bits | Single Edge | Solid Carbide | Upcut Spiral O Flute | Plastic | Wood | Aluminum | Solid Surface | Documents

I watched the video, if you are planning on running these parts often, I'd suggest making a dedicated spoil board for it. Have you ever used any o ring gasketing in your spoil boards? If not, the idea is to offset your cut by 1/8-1/4" and cut a slot to insert an o ring in with it protruding a small amount. Then drill or cut holes through the spoil board to apply vacuum to the inside of the gasketed area. This works great on parts like you were cutting. On ones that are very small I'd still use tabs and trim them after.

I use 1/4" dia round o ring and I cut a 1/4" wide slot 0.200-0.220" deep depending on the material I am holding. If you have lots of small tight spots, you can use smaller o ring cord.

You may also consider drilling the holes first and dropping dowels into them before you start cutting the perimeter out, works good on slippery parts since it can't slide around once you put a dowel in, then the vac only has to keep it from lifting vs sliding too.

Jason

macgyver said:

I just got done with a good sized job cutting some aluminum on my Komo cnc router, at least it looked like aluminum, nasty, gummy junk. Anyway, I wasn't getting anywhere until I got a new cutter. Someone on here suggested an Onsrud cutter and I ended up getting a 65 series 'super O'. I was cutting a kajillion 2" square holes in 4x10 sheets and it had to have a 1/8" corner rad, so I used the 65-23. It made all the difference, I ran at 10K and 30 ipm. Could have pushed it harder I think, but wanted to be able to walk away from it so left it at that.

:: Super O Router Bits | Single Edge | Solid Carbide | Upcut Spiral O Flute | Plastic | Wood | Aluminum | Solid Surface | Documents

I watched the video, if you are planning on running these parts often, I'd suggest making a dedicated spoil board for it. Have you ever used any o ring gasketing in your spoil boards? If not, the idea is to offset your cut by 1/8-1/4" and cut a slot to insert an o ring in with it protruding a small amount. Then drill or cut holes through the spoil board to apply vacuum to the inside of the gasketed area. This works great on parts like you were cutting. On ones that are very small I'd still use tabs and trim them after.

I use 1/4" dia round o ring and I cut a 1/4" wide slot 0.200-0.220" deep depending on the material I am holding. If you have lots of small tight spots, you can use smaller o ring cord.

You may also consider drilling the holes first and dropping dowels into them before you start cutting the perimeter out, works good on slippery parts since it can't slide around once you put a dowel in, then the vac only has to keep it from lifting vs sliding too.

Jason

Click to expand...

That is the same bit I cut these parts with I called and talked to a Tech @ Onsrud and he told me that the 65-023 bit and the 65-010 bit I used were more of a universal bit and that I should use the 63-600 series they specifically made for aluminum so I ordered some of those for the next batch.

I use Onsrud bits on everything I cut with this router. I find if I use their recommended chip load it is too aggressive they must have better hold down but I also don't use a cleanup pass in the plastic I cut.

My spoilboard is glued to the vacuum plenum and I use the vacuum to hold a lot of different parts I may add some dowels in the perimeter to help hold that would be a good idea. I do that for some double sided machining on some UHMW parts I make. I was also going to try laying some plastic on the parts as they are being cut out that will seal off the profile cuts so they don't lose so much vacuum. I left tabs .003" x .250" around the parts to keep the parts from shifting and hold the sheet together that worked good. I cut the tabs afterword with a multi tool with a wood blade that worked good and was fast I sprayed WD-40 on the multi tool blade occasionally to keep it from galling.

How thick was the material you were cutting? Did you cut through in one pass? I actually think it may have cut better if I had cut through in one pass from the sound the bit made on the first pass compared to how it sounded when it cut through on the second pass. I also did not run a clean up pass I may do that next time I got a little chatter in spots but most of it looked really good.

Mike

Re Dedicated spoil boards.
A guy I knew used a dedicated spoil board for various jobs like yours, and came up with a wonderfully simple solution.
If say he was cutting parts with a 6mm cutter he first went round the spoil board cutting the ''job track'' in to the board with a 10mm cutter under 1mm deep , then brush painted the track he'd cut with a quick drying solvent based paint (old car body cellulose actually)

Result, ...much less loss of vacuum, so he could push it harder etc etc, reckoned the time saving from two batches of parts more than covered his time spent making the board.

The sheets I ran were 0.080" thick. It was in 1 pass, I may try that other cutter in the future.

I would suggest bolting or screwing the spoil board down when it comes time to put another one on there, that would allow you to swap them out for different jobs. Cut a gasket channel around the perimeter of your plenum so it seals.

Also alot of people forget to seal the edge of their spoil board. A trick I use to show people vacuum loss is to take a piece of shrink wrap and hold it up to the edge of the spoil board or anywhere along the parts and table and it will get sucked in if there is a leak. It also is good to demonstrate how porous mdf and other materials are.

I went from a 40hp vac pump at my old job to a 10hp on my machine so I can't get away with as much as I used to.

My vacuum hold down is supplied by 2 Built in house vacuum motors I have them plumbed to run single or in parallel each motor draws 7.5 Amps @ 220 volts 1Ø. I have used this system since 2008 and it works fine for plastic not cutting through leaving a .050" skin and trimming out the parts with a laminate trimmer. I could add 2 more motors they are cheap about $120 each. I held this job with this system I have 5 zones so as I cut the profiles and started losing some vacuum I just shut off the section cut after it passed that zone. Next time I will put some dowels in and cover the area cut with some clear plastic sheet that should work. Nice thing about my vacuum hold down system is it only cost me $400 to make it and it is made to hold most of the parts I make. Many of the plastic parts I make are so small they could not be held by vacuum if I cut through. I make parts as small as 1.5" x 1.25" with no gaskets and hold them by not cutting through on the profile cuts I do go through on drilled or bored holes.

Mike