Cutting aluminum with cutting fluid and vacuum?

(Donavon Yelton) #1

I finally got my 6061-T6 sheets in (1/16" thickness) and I’m ready to start cutting.

I have some TrueTap cutting fluid I got from Amazon and a Festool CT26 with the dust head designed by @mbellon attached.

How am I supposed to go about cutting this stuff with the cutting fluid and the vacuum? Pardon my ignorance, but is it perfectly safe to have the Festool running during the job? Also, how do you actually go about applying the cutting fluid (obvious noob alert with that one)?

I work where we have very large CNC machines and I’m used to seeing jets of this stuff, but I have no idea what the protocol is for doing it on the Nomad. I’m not sure I want to open things up while it is running and cutting aluminum. If you do a pause, doesn’t the bit keep spinning at speed? Not sure I’d want to peel back the skirt from the dust head to apply cutting fluid if the bit is still spinning.

Even without the dust head on, I just want to make sure I’m being as safe as possible. Am I missing something here?

:runs away quickly:

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(Mark Bellon) #2

As far as having body parts in the work volume of a CNC machine, that is a serious danger. To lubricate a metal working job, I use a spray bottle and just give the current cutting position a “hit”. I can hit a spot quite accurately, even from several feet away (usual distance is less than 1 food). NO body parts in the work volume.

Cutting Al alloy dry can be done quite efficiently - no lubrication is necessary but the correct end mill is definitely required, along with the appropriate feeds and speeds.

You’re free to remove the brush plate but still use the CT26 as this provides some pickup… mostly the air turnover prevents things from getting hot.

What to try and pick up the swarf (and leave the brush plate in place)? There are a number of approaches. Pause - as you point out - is one of them.

Another approach is modifying the dust head to add a micro drop dispenser. The flood lubricant of many machine is dying out - it’s wasteful, expensive and bad for the environment. The micro drop and other technologies do as well or better - and use much less lubricant.

Yes, flood is still necessary for some jobs and for some situations. Sometimes one just has to clear the swarf fast… not because of the lubrication aspect.

I roughly know where things are going to go and paint a bit of lubricate where necessary.

mark

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(Donavon Yelton) #3

I’m using 3 flute end mills meant for aluminum (what our tool and die mgr at work suggested to me). Given that this is a thin sheet, I would either be okay cutting dry or just applying a layer of cutting fluid prior to the job start? My work area is ~3"x3". The machine scares me (which is probably good) when it is running so no, I don’t want to go anywhere near it with it open while a job is running.

I thought about making a little door with an auto sealing trap where I could just stick a long dropper in there and lubricate from afar. I haven’t a clue what I would use or what’s out there for this.

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(Mark Bellon) #4

I’m using 3 flute end mills meant for aluminum (what our tool and die mgr at work suggested to me). Given that this is a thin sheet, I would either be okay cutting dry or just applying a layer of cutting fluid prior to the job start? My work area is ~3"x3".

I would try dry first, shallow cuts and appropriate feed and speed. Search and you should find a few of the numbers used by others.

A layer of lubricant will help a little but after the first cut it’s not particularly effective.

The machine scares me (which is probably good) when it is running so no, I don’t want to go anywhere near it with it open while a job is running.

That is very healthy. I remember my early CNC days. Scary. Even starting a new machine can be scary… the Nomad threw me a few unexpected things. Pretty easy compared to the bring up of other machines.

I thought about making a little door with an auto sealing trap where I could just stick a long dropper in there and lubricate from afar. I haven’t a clue what I would use or what’s out there for this.

That’s fine as long as the no body parts in the work volume of an active CNC machine is kept. Hmmm… how to do that…

A microdrop does pretty much what you saying. You set the rate and it drops automatically.

mark

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(Danny Harper) #5

I would consider moving to a 2 flute 45 helix over a 3,you will get much better chip clearance from the tooling.

I tend to cut dry,saving lube until im near breakthru and even then it needs a little hit,not drenching.
The only time I go all in with lube is when im using a chamfer mill.

I use WD40 with a straw nozzle to lube or Paraffin,mainly as it works very well and is cheap. Beware of getting WD40 on the delrin components as it shortens their life.

And,as mbellon also states,its very GOOD that you are scared of the machine,it will give you a level of respect for it that will save your fingers/limbs/eyesight. Hands out of the machine area while its running is a given.

Cut Quality?

Yes,plenty.

18k on the spindle,400mm/min and .2mm DoC using a 3mm endmill. Its not fast but the cut quality is very good and it quiet…ish. I prefer it like this over flat out.

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