Thread: Aluminium cutting
Probably slightly off topic, but related to material removal. About 3 years ago I visited a factory that had a number of CNC mills, one of which was making some ally boxes for race car electronic enclosures and they were specified as machined from solid billet. The way that the material was removed for "pocketing" was that the machine was programmed to plunge drill a series of holes about 50mm deep with something like a 20/25mm drill, each hole slightly overlapping the next such that it left a series of islands standing and serrations round the edge. The finish milling then simply meant removing the islands and cleaning up the edges. Of course this was a commercial machine, through tool cooling etc., but the factory owner told me that it was by far the quickest and cheapest way to remove material. I realize that this method is probably well known, but I thought it was interesting. G.
I have just ordered a heap of aluminium and Five 1/8 single flute bits for cutting aluminium. When They arrive I will start at one setting and keep a note of exactly what the feed and speed is and go from there. The plan is I will take a slice right through the aluminium from one side to the other ie. mill a slot 1/8th wide.
The aluminium is 6082 T651 the end mill is 1/8th (3.175mm) carbide it is 38mm long 20mm will over hang the collet the cutting edge is 12mm long, the feed it will be 325mm per minute, plunge is 254mm per minute, the spindle rpm 12000, and the depth of cut will be 1mm.
Any advice about changing some of the settings will be welcome.
Well that didn't work out well, cutting 6082 aluminium. The settings were. 12000rpm. Feed rate of 325mm per minute. Plunge rate of 254mm per minute, with a depth of cut 1mm. I used a 3.175mm single flute carbide bit, but as soon as the bit cut in to the side of the aluminium the bit broke, so I tried a cut depth 0.5 mm. The bit did cut through the aluminium of 60mm wide but by the time it was at the end there was a poor shaving curl and when I got down to 5.5mm deep it broke that end mill as well. I did use cutting oil and it was a wash with it, also there was no smoke coming from the bit so it was not getting hot. So what do I do now should I reduce the depth of cut a little more or speed up feed rate. Or is it that I am using to small a size end mill?
Hi Bush flyer,
I recently cut some elongated slots with a 3mm carbide bit without any problems. I don't use the 3mm cutter much (tend to use 6mm) so haven't experimented but the following settings worked OK:
30mm/min plunge rate
The 4 slots were 5mm wide, 15mm long, and 10mm deep (other side is pocketed 10mm). See photos below.
(I was actually surfacing the whole part in this photo - hence the 6mm cutter in the collet, not 3mm, but you can see the slots I was refering to)
I flooded the holes with duck oil as soon as cutting started. There was no smoke, no screeching, just a soup of very small chippings swirling around in the pocket as the cutter did it's job.
The Following User Says Thank You to routercnc For This Useful Post:
Thanks for the quick reply, That's just what I wanted, your setting for slotting aluminium I will try again tomorrow with that settings. Would it be possible that you could also tell me the settings you are using with your 6mm single flute end mill as well I have 25mm thick aluminium to cut so am thinking I will get a few 6mm end mills.
Edit: This might seem a daft question but to me the thread is going round in a circle until Bush Flyer uses a cutter of the same type and most importantly, brand, that others are using when they suggest cutting parameters. The difference between a good cutter and a bad one is chalk and cheese.
Last edited by EddyCurrent; 04-05-2014 at 09:10 AM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
I bought some cheap 3mm single flute cutters from Ebay, whilst the cutters themselves are good the initial edge applied to them is a little random, fortunately the single flute cutters are very easy to hand sharpen and and a quick touch-up on a diamond wheel is all they needed to get them cutting cleanly. They're not listed as suitable for Aluminium but I've used one on Brass, Bronze, Aluminium and Titanium and I'm still on the first one of a pack of 10 ;-)
We have success, Using the settings from routercnc I was able to cut aluminium without breaking the end mill or blunting the end mill. Now just to fine tune, I used a zig zag plunge from zero Z axis height and it was too slow I think at the low plunge depth I will try it without the zig zag or increase the plunge rate and keep the zig zag, Now all I have got to do is the same for a 6mm end mill. Thanks again routercnc.
Glad it helped.
3mm bit was carbide 2 flute slot drill from 'bargain tooling' on e-bay:
3MM CARBIDE SLOT DRILL / CUTTER 2 FLUTE *NEW* | eBay
I don't usually cut much aluminium, so am not an expert, but I have been cutting a fair bit recently for the upgrade parts. The setup I'm using is as below. This is what works on my machine, but no guarantee for yours:
e-bay again from bargain tooling. Can't find link to original part I bought but similar to this:
6MM CARBIDE SLOT DRILL / CUTTER 2 FLUTE *NEW* | eBay
(it feels like it could take 900-1000mm/min which is a better load, but running on 26V machine concerned about stalling/missing steps. Still waiting for new drivers . . . )
plunge rate: 150mm/min
(tried 1.5mm today and tends to squeal / resonate - upgrade parts should improve things)
spindle speed: 12000rpm
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