[eloid]

I would like to machine parts for a future cnc, out of plate aluminum
What grade of aluminum to use to acheive good clean cuts with small
cnc router... and cost Effective.

What are the do and dont etc...

would be cutting 1/2 to 5/8 thick plate material for things like R/P mounts
nema34 motor mounts... z axis parts, making the gantry beam... etc.

[Geof]

6061 is the best general purpose alloy; I think the temper you want is T6, this machines, drills and taps very nicely. A somewhat more expensive alloy is 7075 which also machines very nicely. Don't get any of 5xxx series alloys because they can be difficult to machine nicely. 2024 is okay but probably way too expensive.

Do's and don't's?

Do use a cutting lubricant for all cutting, drilling, tapping and machining. You can buy a proper cutting fluid or use something like ATF automatic transmission fluid just by brushing it on along where you are cutting.

Don't cut or drill without making sure things are clamped down nice and firm.

[gd.marsh]

Cutting alum with a small router will have to taken real slow. It's not impossible, but you're going to have to take very light cuts.

As soft as aluminum can seem .. it still requires much greater cutting force than wood. It can be real hard on routers because they're not made to handle the lateral forces necessary. One other thought, if you can live with a less than perfect edge, use a 1/4" rougher end mill. That will make it a little easier on your router also. You can always put a standard cutter back in for a finish cut.

I've had good results using WD-40 as a cutting fluid on aluminum although I know there's been much debate about it's worth. Best of luck!

[raymondg]

eloid,
You don't say where you are located, and Geoff's reply is assuming North America, so I will too. 6061-T6 is widely available, but one trap to look out for is some metal suppliers will try to pass 6063 off as similar. It is not. Stay away from 6063. You say you want to make parts for a future CNC, so Mic-6 also comes to mind, as I have seen numerous builds here on the zone using it. I'm still getting a little used to it myself, and would definitely heed the advice to use cutting fluid as it will want to stick to your cutters.
Where possible, design for easier ops like facing, edge milling, and drilling over slotting and pocketing, as they are much easier on your machine, and therefore more likely to yield satisfactory results. Where possible, a bandsaw is your friend. Look at Widgetmaster's work for excellent examples.

Raymond

[jsheerin]

Personally I find pocketing works better than drilling, at least with a router. I do most of my machining of 6061 dry, but drilling requires some type of cutting fluid or I get chips welding to the cutter causing them to break even when pecking and retracting the cutter fully between pecks. I typically feed into the material at 10 degrees or less and go about 1/6 of the speed and depth of cut as I do for wood.

[eloid]

eloid,
You don't say where you are located, and Geoff's reply is assuming North America, so I will too. 6061-T6 is widely available, but one trap to look out for is some metal suppliers will try to pass 6063 off as similar. It is not. Stay away from 6063. You say you want to make parts for a future CNC, so Mic-6 also comes to mind, as I have seen numerous builds here on the zone using it. I'm still getting a little used to it myself, and would definitely heed the advice to use cutting fluid as it will want to stick to your cutters.
Where possible, design for easier ops like facing, edge milling, and drilling over slotting and pocketing, as they are much easier on your machine, and therefore more likely to yield satisfactory results. Where possible, a bandsaw is your friend. Look at Widgetmaster's work for excellent examples.

Raymond

yes north america, I have lots of end mill i have collected... but only have my hand held router and small cnc router...I have nothing slower than my router ( with speed control) to cut sheets with ( should get Onsrud router bits for aluminum ... just wondering if end mill is best suited to be used in a router?

I can use the table saw for staight cuts...I want cut all my complex cnc parts on my small cnc.

[jsheerin]

I've used mostly 1/4" diameter 2 flute center cutting carbide endmills for cutting aluminum using my router at 10k rpm. Nothing fancy - just ones I get from MSC on sale.

[ilya]

... Don't get any of 5xxx series alloys because they can be difficult to machine...

Geof, can you please explain what are particular difficulties regarding machining 5xxx alloys? I don't have 6061 here, so I was considering the 5xxx series.

[LazyMan]

Mic-6 machines like butter and does not gum up too much. Its no more expensive than "normal" aluminum and can actually be just a bit cheaper. I used MIC-6 to build my router and has worked perfectly. Mic-6 is stable, as it has very little internal stresses so deformation from machining and temperature changes are very low. Mic-6 is not as strong as extruded aluminum but works great for parts on CNC routers. Its not something you would use in a motorcycle part though.

For lubricant I have had great success with WD-40, and better results with "tap magic" fluid for aluminum.

[eloid]

thanks guys. Im in ontario, canada wondering what a good price for
6061-T6 or simular material . Can this material be chrome electroplated after machined?

[jsheerin]

Try www.speedymetals.com for price info. I've found they're pretty good.

[PaulRowntree]

thanks guys. Im in ontario, canada wondering what a good price for
6061-T6 or simular material . Can this material be chrome electroplated after machined?

There are several branches of Metals Supermarkets here in Ontario.

http://www.metalsupermarkets.com

Cheers!

[cncsigns]

Geof, can you please explain what are particular difficulties regarding machining 5xxx alloys? I don't have 6061 here, so I was considering the 5xxx series.

the problem with the 5000 series aluminum like 5052 is it is very soft and that causes the aluminum chips to stick to the cutter being used, it also creates more of a tearing effect on the cut edge so the cuts are not as smooth,
I have not tried the Mic 6, but 6061 seems to cut the best and it leaves a great finish on the cut edge, at least this is my experience...