Need help on Milling small Aluminium pieces

[disonance]

hi all,

I'm using a Parker Daedal XY table - 300AT series, this coupled with a Dremel Tool on the Z axis.

So far, i've been milling PCBs and MDF boards, these works like a charm. However, i'm thnking of milling some Aluminums pieces now, small ones, no more then 1x1 inch , thickness no more then 0.5 inch.

What kind of drill or milling bit shld i use? I've already broken 2 1.6mm drill bits...

[Geof]

Make sure you are using an aluminum alloy that is suitable for machining; 6061, 6262, 2011, 2024 are all okay.

Always use some coolant/cutting fluid; aluminum tends to stick to the tool and jam up in the flutes of both drills and mills.

For milling use two flute cutters to get best flute clearance for chips; spin the cutter very fast and feed gently. Just brushing the cutting fluid on ahead of the cutter will work or rig up a mister or sprayer.

For drilling also feed gently and 'peck'; that is go down about the size of the drill diameter then retract to clear chips and allow cutting fluid into the hole.

And don't get discouraged if you do still occasionally break drills and cutters; just remember what works and what doesn't work and eventually you will get things sorted out.

[disonance]

thanks Geof,
thats some really good advise. Will give it another shot in the coming weekend, once i get the right equiptment.

[irving2008]

Originally Posted by disonance hi all, I'm using a Parker Daedal XY table - 300AT series, this coupled with a Dremel Tool on the Z axis. So far, i've been milling PCBs and MDF boards, these works like a charm. However, i'm thnking of milling some Aluminums pieces now, small ones, no more then 1x1 inch , thickness no more then 0.5 inch. What kind of drill or milling bit shld i use? I've already broken 2 1.6mm drill bits...

Disonance, I concur with everything Geof has said and would add the following observations; size of the work piece is irrelevant - its feed rate versus cutter speed and size that matters. Also I'm not clear if you were trying to mill with a drill bit (your post implies this) - if you are putting any sort of side force on the tool then it had better be a proper milling cutter and not a drill or it will snap. While coolant helps its not essential if your cutter speed is very high (the higher the better for very small cutters) and your spindle can maintain that under load and you are taking a light cut. A plant or perfume type mister/spray bottle works well.

A lot of people swear by carbide cutters for these small/high speed requirements (then again many argue against them) - its a case of suck and see to some extent.

A 130W Dremel is really the bottom end of the range for milling aluminium, it hasn't really got the grunt needed also they tend to have a lot of runout and sideplay so dont expect the accuracy you get on a PCB for instance, but it will work as log as you are careful and get the feed rates right - light cuts (0.05-0.1mm)/higher feed rates are better than low feed rate/heavy cut (>.2mm). But it must be a cut and not just a polish - too light a cut can burn out the tool, especially at Dremel speeds! Don't try to cut the full tool width - aim for no more than 70%.

And just keep playing tii it works out...

Hope that helps...

[solodex2151]

I concur with Irving about the Dremel. You are going to need to take a very light pass if you use it. Consider either getting a router with some aluminum endmills designed for the higher spindle speeds or getting a Taig headstock or similar that can run a standard endmill at the slower spindle speeds required.

The suggestion about the coolant is a must. Consider setting up a coolant bath with a recycling system and a pump. If not, give the work piece and bit a shot of coolant regularly when cutting aluminum.

On a last note, a 1.6mm diameter cutter is very small. Because it's very small expect to break quite a few if you don't get your chip loading right. It's a lot more fragile than larger diameter cutters.

Nate L.

[irving2008]

I just acquired this for my CNC mill... £40 ($80) on ebay... 500W, no measurable runout, 6mm collet and a standard 43mm mounting collar... should machine aluminium quite well with the right cutter...

[disonance]

Originally Posted by irving2008 I just acquired this for my CNC mill... £40 ($80) on ebay... 500W, no measurable runout, 6mm collet and a standard 43mm mounting collar... should machine aluminium quite well with the right cutter...

Irving, now that looks really impressive compared to the dremel i have mounted.

I'm begining to think that its probably better to head towards getting a bigger router and as per Solodex's suggestion, Use bigger Diameter Cutters. Milling Alu on a dremel would probably be pushing it

yeah, 1.6mm is small. On hindsight, i shouldnt have even bothered haha



thanks for all the info guys.