Ethanol mist for cutting aluminium

[cropwell]

Ethanol is the alcohol we drink and in moderately low doses can cause delusions of adequacy. Methanol, on the other hand is a poison which can cause permanent nerve and brain damage at fairly low doses. Methylated spirit is Ethanol with 10% methanol, violet dye and pyridine, which makes it taste horrible.

However, the most dangerous part of ethanol is that is very flammable and burns with an invisible flame and an ethanol mist would be an explosive mixture.

I like the idea of cold air - but I wonder what volume of air it needs to get enough temperature drop through adiabatic expansion to be effective.

[matt-b2]

I've given up on mist coolant - It might seem the more convenient than flood coolant at first glance but my experience has taught me that it causes more problems than it solves.

1. It doesn't matter what sort of droplet size you're getting from your mist system, if you're using a high speed spindle, the droplets atomise as soon as they hit the cutter and fogging becomes unavoidable. Decent forced ventilation becomes a necessity unless you want to end up with some sort of lung disease or an explosion.

2. Depending on what cutting fluid you are using and the humidity of the climate you are in (the UK is quite humid), the air supply to the mist system will need to be suitably desiccated to prevent moisture getting into cutting fluid reservoir. Moisture can end up emulsifying with the cutting fluid causing it to clump up and cause blockages.

3. In order to clear chips effectively, mist systems get through a lot of air - be prepared to put up with a lot of noise from your compressor, make sure its up to the duty cycle and can deliver the flow. My old compressor (now dead) would run pretty much continuously whilst the mill was running. As I did not have a separate room for it, this was incredibly irritating and didn't do my electricity bill any favours. Ultimately, I think the demands my mist system put on my compressor lead to its premature death.

No doubt, there are plenty of people out there who have had better luck than me using mist cooling, but I'm done with it. I also appreciate that it is not always practical to use flood coolant on some machines. In my case, however, fitting flood coolant isn't a problem and the resultant mess is easier to tame than atomised coolant floating about the shop, getting into all sorts of places it shouldn't. Running flood coolant is also quieter, more effective at clearing chips and uses less power.

With regards to just using cold air, I've never had much luck cutting aluminium dry. I use uncoated carbide tooling and regardless of what speed I'm cutting at, I always end up clogging my cutters without some sort of lubrication present.

Matt.

[magicniner]

I use uncoated carbide tooling and regardless of what speed I'm cutting at, I always end up clogging my cutters without some sort of lubrication present.

Have you tried single flute cutters?

[Hallettoil]

As a snippet of useless information. Paraffin has been traditionally used in machining, cutting and forming Aluminium, BUT... it is, as you know inflammable.

In the home workshop if you are to be machining Ally regularly, you may well see if you can obtain EDM Fluid/Dielectric Fluid used in Discharge machines.

I have seen this on Ebay at £55 for 25 litres delivered and it is what is know as.. De-Odourised Kersosene.

The flash point is actually increased which makes it a little more friendly and you could try adding maybe 2% of Rape Cooking Oil. You would have to experiment with this.

This would increase further the flash point whilst giving you an added lubricity additive. I can't guarantee that at some point you may be close to flames so keep a fire extinguisher (powder) handy.

Should you ever be unfortunate enough to have flames, remember that the vapour can get through the powder and can jump across to an ignition source so keep your third eye sharp.

This product is used in hand cleansers and again, be aware of skin and air passages and I don't mean the drafty entry!

I've given up on mist coolant - It might seem the more convenient than flood coolant at first glance but my experience has taught me that it causes more problems than it solves.

1. It doesn't matter what sort of droplet size you're getting from your mist system, if you're using a high speed spindle, the droplets atomise as soon as they hit the cutter and fogging becomes unavoidable. Decent forced ventilation becomes a necessity unless you want to end up with some sort of lung disease or an explosion.

2. Depending on what cutting fluid you are using and the humidity of the climate you are in (the UK is quite humid), the air supply to the mist system will need to be suitably desiccated to prevent moisture getting into cutting fluid reservoir. Moisture can end up emulsifying with the cutting fluid causing it to clump up and cause blockages.

3. In order to clear chips effectively, mist systems get through a lot of air - be prepared to put up with a lot of noise from your compressor, make sure its up to the duty cycle and can deliver the flow. My old compressor (now dead) would run pretty much continuously whilst the mill was running. As I did not have a separate room for it, this was incredibly irritating and didn't do my electricity bill any favours. Ultimately, I think the demands my mist system put on my compressor lead to its premature death.

No doubt, there are plenty of people out there who have had better luck than me using mist cooling, but I'm done with it. I also appreciate that it is not always practical to use flood coolant on some machines. In my case, however, fitting flood coolant isn't a problem and the resultant mess is easier to tame than atomised coolant floating about the shop, getting into all sorts of places it shouldn't. Running flood coolant is also quieter, more effective at clearing chips and uses less power.

With regards to just using cold air, I've never had much luck cutting aluminium dry. I use uncoated carbide tooling and regardless of what speed I'm cutting at, I always end up clogging my cutters without some sort of lubrication present.

Matt.

[cropwell]

Cutters for ali need to be Open Architecture to allow chips to clear, single flute allows this, but this guy (Roy Kloss) does a range of cutters for ali have a look - http://www.sorotec.de/shop/Cutting-Tools/END-MILLS/

I am not endorsing Sorotec but he has a good range and I have been satisfied with his service. The cutters are probably sourced from China - but faster delivery if you are in a hurry, otherwise you might find the same on Alibaba.com.

Cheers,
Rob

[Hallettoil]

BY THE WAY... upon heating ...Rape Oil can be gummy (Chip fat residue) be aware of this too

[cropwell]

Rape Oil can be gummy (Chip fat residue) be aware of this too

You don't have to heat it for it to go off. I tried it as a coolant on my lathe, it got everywhere and went sour and sticky, took bloody ages and hard work to clean it up.

[Hallettoil]

It is a vegetable oil and is totally unsuited to the task as you say. Some vegetable oils can actually do the job but they do require a certain "tweak!"

I did say... : add to Deod Kero at say 2%.

You don't have to heat it for it to go off. I tried it as a coolant on my lathe, it got everywhere and went sour and sticky, took bloody ages and hard work to clean it up.

[matt-b2]

Have you tried single flute cutters?

I've been using 2-flute cutters. Not tried single flute yet.

[Billythefish]

You can definitely do it. You probably also need to run it in conjunction with some sort of extraction, filter, return system. A few things to consider. First of all you dont use much with a minimum quantity system. You dont want to be breathing to much so it is sensible to suck out of the work area and filter/recondense. You could make a system to do this. There are many advantages....