[GaryWilliams]

*** There are so many forums, I have no idea if this is the correct one for this question, sorry. Please move to the correct forum, Cheers, Gary ***

Hi All,

For my first aluminum job, I need to mill a series of 6mm wide slots, 10mm deep in aluminum. I have a decent 6mm, 1 flute end mill. Looking at various Utube articles, most people have an air blast system of some kind aimed at the endmill to keep the slot clear. Can anyone recommend such a system I can fit?

If I have an air blast system fitted, do I also need a coolant feed? It would be much cleaner if dry milling was OK.

Can the air blast be replaced by a vacuum device instead?

Cheers

Gary

[pleasedontcrash]

I used to do a lot of aluminum work on a small tool room mill haas cnc. All we had was a air blower/mister to keep the tool cool and chips clear. It was a simple setup, just an air regulator going to a oil reservoir with a little valve you could turn to regulate the amount of air and oil you want to come out of the nozzle. Im sure MSC has a few you could choose from.

[awerby]

Vacuum works pretty well for wood chips, but metal is a lot harder to pick up that way. Usually aluminum is worked wet, so an air-blast doesn't work too well to move the swarf around. The usual way it's done is to blast the chips out of the way with a strong jet of coolant, and then collect them, convey them away from the work area, filter the coolant out and recycle it, and compress the chips. If you google "chip conveyor" you'll get an idea of how these systems look; in many shops there's more space devoted to this process than to the milling machines themselves. But how well a given system will work depends on the type of chips you're making. Long stringy ones behave differently from small dust-like particles, so you need to examine your milling process and choose a system that works with it.

If you want to make 6mm slots with good edges, it's best to use a smaller cutter, and take a finish pass once you've cleared the slot. Cutters work better when they only have to cut on one side at a time.

[davek0974]

What machine are you running?

I just started using a mini-mill with a 24,000rpm spindle, built for aluminium. I use a air-oil mist system i built using plans from the 'net, they are quite popular and easy to build, Google "fog-buster" or "minimum quantity lubricant" I run a mix of paraffin and oil probably 95% paraffin and 5% oil. The jet is aimed right at the cutter and is 99% air - just the tiniest amount of fluid, there is no mess and it works very well.

I would not use a "mist" type unit - they run much more messier as the fluid is atomised and ejected as a fog or mist - this is what makes the mess and probably health issues too.

Definitely run your 6mm slots on a 5mm tool with maybe a 0.2 - 0.1mm allowance for a finish pass at the end, slotting always produces a rough odd-sized slot.

[forhire]

For my first aluminum job, I need to mill a series of 6mm wide slots, 10mm deep in aluminum. I have a decent 6mm, 1 flute end mill. Looking at various Utube articles, most people have an air blast system of some kind aimed at the endmill to keep the slot clear. Can anyone recommend such a system I can fit?

If I have an air blast system fitted, do I also need a coolant feed? It would be much cleaner if dry milling was OK.

Based on your single flute selection I'm going to assume your running a router. I also assume your endmill spiral is an up cut as your slotting.

The most important value to figure is your chip load. Chips carry away heat. Get the chip too thin and it will melt and gum up the flutes. Too thick and the machine may struggle/chatter. For dry cutting aluminum with a 0.25" (6.35mm) endmill I like about 0.002" to 0.003" IPT (0.05 to 0.075 mm/tooth) when using a router. If the router is rigid enough you may go heavier. Onsrud lists the single flute at 0.003" to 0.007" IPT (0.075 to 0.18 mm/tooth) in their guide.

You might plug in your values to a calculator like fswizard to get a starting point. It supports both inches and metric.
FSWizard - Advanced Online CNC Speed and Feed Calculator

As for the cooling. A lot will depend on your router. If your using an mdf waste board that is subject to adsorbing water you want to limit the moisture. So flooding is likely out.

An air blast nozzle may be enough. I'd start there and see how it goes. The air will keep the chips clear and prevent re-cutting chips. The drawback is it has no lubricity so you'll likely have to run a fair chip and coated tools. You can also brush lube on the path.

A cold gun may work but I've never been able to dial mine in quite right on the router. Maybe someone has a working setup and will chime in.

I have a trico micro drop that works really well. I use it on a knee mill but it works well and uses very little lubricant. I doubt it would be much of an issue on a router. It's expensive.

I also use a Fog Buster. I generally use it with a water based coolant. It uses very little and doesn't swell wood much. It's a toss up which is better the fog buster or the trico.

But, my current favorite on the router is denatured alcohol. I started with it in a spray bottle but a few months ago I started misting it. It uses very little. The material stays cool and no clean up. It works a million times better than wd-40. This video shows some milling of gauge aluminum. I've slotted 1.5xDiameter in 6061 with a three flute 0.25" endmill on this router. Air blast with brushed lube caused the parts to get too hot to handle (and sometimes smokes a little). With the denatured alcohol they were cool to the touch.