Cutting Aluminum - Mill One V3

Am I correct to assume " Sienci Mill One V3 " is a better choice for accurately cutting small functional aluminum parts in volumes?

I need to cut small functional parts from aluminum plates ( 1/4 inch thickness by 2" x 3" ) repetitive in relatively higher quantities.

Max, I and several other people on the forum have used the LongMill for lots of aluminum parts. With careful setup I have gotten accuracies on 3/8" aluminum plate within ± 0.001". Keys for both the Mill One and the LongMill, and really any other CNC, are 1) Proper design - Minimize extremely thin walls, confirm the diameter of your cutter with tests, not just by mic, and measure the thickness of your stock carefully; 2) Good stock hold-down - Secure in all 3 axes, and 3) Use of correct settings. This is where you optimize the machining settings for what’s most important to you - cut quality, cycle time, accuracy, surface finish, etc.

Because of its table size my choice would be the LongMill. You can easily secure a 24"x24", really 30"x32", sheet of aluminum and cut, depending on your outside part contour, a grid of 6 or 7 by 10 or 11. Universal G-Code Sender has a cool replicate feature that lets you load one program and duplicate it in an array to cut many parts at once. There are web sites that will arrange your parts on the available sheet to use the plate most efficiently. If you’re a Fusion 360 user, it can now do the optimization internally. This combined with the use of parametric design makes producing large numbers of parts much simpler.

When you get ready, no matter which machine you choose, let us know. We can probably save you some head-scratching, although that is often the best part.


1 Like

Bill, thank you very much for encouraging reminders about the LongMill advantages. It’s a fact that actually the large bed of LongMill would be beneficial for cutting multiple small parts from the same aluminum plate. That’s of course after due diligence in extra tightening of steps/mm and Z-height setup across the bed. I will be screwing the plates to a custom accessory plate ( MDF ) on the top of the bed with aluminum screws ( just in case of run off ).
I am going to dig into CAM optimization feature of Fusion360 today. Professional help at the right price is always a good deal.
Before all the cutting I have to re-learn the arts and craft of Aluminum Anodizing and that’s the determining factor. I’ll post some images as soon as I have worthy results.

Max, if you’re making 3" long parts your steps/mm error is probably trivial. My experience was that the biggest error came from the nominal 1/8" single flute mills I was using, and I’m guessing you will use for such a small part. Their diameters were very hard to mic due to the shape of the flutes, and seemed to be 0.120" instead of .125". No big deal. When I made test parts and mic’d them, all of the pockets were several thou undersized. I re-posted the toolpath in Fusion 360 using several different diameters until I closed in on 0.118" for the cutter diameter, which was right on. This wasn’t just for one particular cutter, but was true over several from the same supplier. I think the error was partly the actual diameter of the cutter, and partly from deflection of the cutter during the run. The deflection alone may be enough to cause 0.5-1% error when you’re making small pockets or contours.

Anyway, what I really learned was the LongMill, with proper setup, like keeping the router high in the mount, cutting close to the ends of travel in the X direction if possible, and keeping DOC and cut speed down to reasonable numbers, is perfectly capable of making close tolerance parts.

When you get close to trying aluminum, hit me back and I’ll pass on some of the setup numbers I use that consistently give good results.


1 Like