Soft Alumninium

I'm making use of some aluminium sheet I bought perhaps 8 years ago from Radio Spares. Their code 183-944 which they still stock. It may be 1050A SIC

It's like machining plasticine.

When I drill it it seems like the material is melting more than cutting, so if forms long strands that clog the drill, even if I pause lowering the drill bit. It still forms a continuous thread which clogs the drill. it's also easy for the drill to jam and overload my poor little CMD10.

Trying to countersink is works. The cutting edges clog up almost immediately and I need to pick them clean every few seconds.

Muck the same with milling, though that's a little easier.

Are there any tricks and tips that will help. For my next operation I think I will be machining a long channel and I'm not sure how well that will go.

Thanks

Iain

WD 40 works well as a lubricant on Ali, personally I wouldn't use 1050 for parts that require machining, that stuff is better kept when a part requires forming, its ductility is good but its horrible to machine.

Shaun

WD40 does leave a much better finish on the part, and lubricated the toolbits, stopping the Ali cold welding itself to the tip of the tool.

+1

A hint is that 1050A is only available as sheet, for sheetmetal work.

When using it I normally hand drill small holes and mark out and chain drill and file larger openings. I machined the stuff once; to make an instrument cluster for my neighbour's Moggy Minor where I needed to trepan the larger holes. My analogy would be that it machines like fudge, but doesn't taste as nice. Slow speeds, plenty of lubricant (I use WD40 too) and even then you spend ages deburring.

Andrew

Hole in that stuff are best made by punching, bigger ones with a chassis punch or similar. It was good when I was making radios while I was working in aviation, I used Alclad for chasis work, harder, and easier to work that the aluminium usually used, Oven trays come to mind.

Ian S C

.

I was about to mention that too, Ian

But the material at RS Components 183-944 is 6mm thick.

... Which is a bit much for my Q-Max Cutters.

MichaelG.

Aluminum that soft is better worked with wood working tools. A brad point drill will remain centered and not create a 3 lobed hole. If the drill is clogging I suspect you are over feeding it. That is easy to do in soft material. For larger holes a Unibit works well. For interior cutouts on thin sheet the material can be cut with a woodworking chisel providing there is suitable backing material, like UHMW.

Back when the place I worked made things in the uk rather than ordering them from foreigners our stores stocked two grades of Al one with green plastic sheet covering and one blue. They were both the same composition but one was heat treated to be hard and cracked if you bent it and the other was well annealed and bent nicely. Both were expected to be drilled as is the sheet you have but we just stopped the downfeed for a moment to break the spiral chip. I find the long spirals behaviour an advantage as I can control the chip length to make clean-up easier.

So if it is a problem for you probably a heat and quench will harden it up. May have side effects though.

If the material is 1050A then it is not heat treatable; although it can be work hardened to a limited extent.

Andrew

1050A is the cream cheese of aluminium. It is not a machinable grade, really. Punch, fold and shear it. A somewhat more widely useful alloy, that's still a bit like 1050 for softness is 5251H22.

Given that you have it, can't suggest any further help.

regards

Richard.

Thanks for all the advice.

Yes I can cut it with a blunt stanley knife.

However, I've had a trial cut of a 5mm slot and that seems to work fine provide I go slow and clean the tool frequently. Helps, no doubt that the tool is brand new and sharp!

Iain

I have sheets of aluminium 1050 and it is officially specified as soft, with poor machinability (see: http://www.aalco.co.uk/datasheets/?gId=1). The 1050A is grade 'O' which is the softest, and I also have grade 'H' which is tempered. You do need to be quite careful when specifying which grade you need when you buy it. Grade O is easy to bend and shape, while grade H14 has a bit more stiffness. 1050 is lovely stuff, but only for forming, bending, etc.

At the risk of offering a counsel of perfection, I would punch holes in sheet up to about 2mm and would not normally attempt to drill it. I consider 3mm and over to be plate. The Q-Cut cutters work ok on the thin sheet, but they need to be sharp. They do, however, produce a nice curve into the hole, on one side of the sheet. At a pinch, you can use woodworking techniques, and I have seen, and tried, some simple techniques like using a woodworking gouge or chisel to punch a hole, then using a shaped fibre or plastic punch to finish the edges with a flare. It may seem like butchery, but produces lovely finished work. I have a Metalman 'corking tool' which is a chisel-style punch with various heads for that kind of job, and its a handy tool.

Bosch produce sheet metal hole saws with very fine teeth, and those may work on 1050, but they are expensive.

I also use some of the 6000 grade bars, plate and flats (6082, 6060, etc) and cast tooling plate. 6032 was formerly called HE30 and it machines quite well. The cast tooling plate is a joy. I would not use a standard milling cutter, though. In my opinion, the only cutter you should use is one produced with a geometry specifically to suit aluminium --- carbide with a single tooth and very aggressive angles. Accupro (sold by MSC Industrial) work very well indeed, but are very expensive. The finish is like chrome, even when machining dry. Use a high spindle speed and feed rate. Lathe tools are the same - you really must use a polished carbide, uncoated tipped tool for good results.

Its a lovely metal to work with, though.

Marcus

Well, I bought this before I knew anything. Radio Spares -what could go wrong?

I'm using it because, we because I've got it. I have no plans to buy this stuff again, but I've started so I'll finish!

The Ally I've bought from other sources (and especially model engineering shops) does indeed like carbide tools - more than steel does.

Iain