Dry milling aluminum in general and 5154 in the hobby

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giel

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i also never had fire and use a LOT with face milling and always with endmilling few drops every 10 seconds keep mill little wet

fire hazard
goes with oil also.. find it best practice to have a fire extinguisher present when milling or turning .
BETTER safe then sorry!!

€ 10 euro to buy a powder extinguisher and for €50 a CO2.. even better as it doesn't give messy powder that eats away at metal!
a blanket is also a small one costs €20
Drawback is that you will have to stop the machine when using it. for obvious reasons 🙄
 

terryd

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i also never had fire and use a LOT with face milling and always with endmilling few drops every 10 seconds keep mill little wet

fire hazard
goes with oil also.. find it best practice to have a fire extinguisher present when milling or turning .
BETTER safe then sorry!!

€ 10 euro to buy a powder extinguisher and for €50 a CO2.. even better as it doesn't give messy powder that eats away at metal!
a blanket is also a small one costs €20
Drawback is that you will have to stop the machine when using it. for obvious reasons 🙄
Hi Gielt,

The flash point for lubricating oil is around 225°C and for olive oil around 210°C so I wouldn't think that there is much of a serious problem there. There is however a problem when vegetable oils are used with cotton cloths. If saturated cloths are kept in bulk, say a waste bin, the heat generated by reactions between the oil and cotton is trapped in the container and can increase until combustion takes place spontaneously. I don't think that it is a problem with mineral oils.

Alcohol on the other hand has a flash point around 14°C hence the admonition not to smoke or strike a match when using but it is unlikely to combust otherwise but yes, a fireblanket within easy reach is the very minimum precaution.

I have had a workshop fire (electrical fault) and it is not a pleasant experience.

first_picture_cropped.jpg

In full blaze

aftermath.jpg


Aftermath. Both cars scrap as well.

Fortunately I had good, but expensive insurance which covered rebuilding and all contents luckily, but I am now extremely, perhaps overly cautious. Picture taken by a neighbour from his garden.

TerryD
 

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giel

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lots of people use vapor cooling these days with oil.. mixes it perfect with oxygen.. finding that dangerous
especially in an open machine!!

a fire extinguisher or at least a blanket is nothing to spare money on.. i know!

have witnessed an lathe catch fire on machining magnesium.. flooded with coolant while running..

operator got on forklift and put the burning machine outside when it started..

machines running pure cutting oil are mandatory to have a buildt in! fire extinguisher that goes off automatic at a certain temperature.

using cutting oil on open machines is a guarantee for cancer!! goes into the lungs and does nasty stuff!! like COPD

using your HEAD is the most important thing to do!
if you use alcohol don't flood your machine DUHH just little on the drill/mill and after a pass vacuum it away never had a fire.. and many people use this with me..
 

oldengineguy

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terryd Was one of the cars in your fire a Triumph Stag? Just curious, tail lights look familiar to one I worked on years ago.
Thanks Colin
 

Bazzer

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also goes for mist cooling,also a big no-go with cutting fluid/oil
(Dutch health code) don't know how the rest of the world is regulated..
I have a mister unit on a CNC router and used it just once and natural common sense told me that the whole thing had risk surrounding it from both health and workshop cleanliness.

Horrible device.
B.
 

Jasonb

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Isn't that why the "fogbuster" type systems are favoured by many as they do not atomise the liquid into a mist/fog

I recently made one for the CNC using a peristatic pump to control flow of liquid into the air supply which unlike the ones that use the air flow to draw up the liquid allow you to control both independently. Not had much chance to use it yet as have mostly been machining other materials but first tries seem promising. Just need to find some fully synthetic cutting fluid in small quantities

 

Bazzer

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Jason

OK mine was a Noga which used a venturi system to draw and then mix/atomise the cutting fluid in the air stream.

What fluid are you using in the video? I stand to be corrected if the type you show are not oppressive to use. I even had extraction on mine and it was nasty.

B.
 

EtheAv8r

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Jason Is that CNC mill a Sieg KX3 by any chance?? If so I would be interested in the peristatic pump and installation details! (As I guess would many others.....).
 

Jasonb

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Bazzer, I only tried it out on the Paraffin that I usually brush on and after 6hrs of running there was no fog in the workshop and nothing much more than if I had been using the brush. However there was the smell of paraffin and as I have the CNC in my attached garage as opposed to the shed here the rest of my engineering stuff is I don't want the smell in the house. Also Paraffin swells the silicon tube in the pump.

E, yes it's a KX3. There are some details in this thread started by another member on MEM forum, he has been using similar on his Emco based machines but with synthetic coolant with no problems and he uses them far more than I do as his workshop is almost all CNC. You will see he has gone for a better pump which is the one on the "cold-end" system that Sebastian End produces. Mike (vixen) as linked his into the LinuxCNC at the moment I just switch mine on and have a pot to adjust flow which can be very low for things like final 3D contours or turned up for adaptive, pocketing etc


The air flow is also very low and only needs about 10psi to clear chips immediately around the tool so they are easily contained within the basic "trough" that the KX3 comes with. That 6hrs of the flywheel patterns used 40-50mls of liquid, less than if I were stood there brushing it on but as I can now leave it to lubricate itself I don't need to be in the workshop except to change tools and just give the odd eye to what is going on.

I can also just run air when machining other materials to keep the chips away and due to the liner within the Locline hose there is very little residual liquid when you finish one wet job.
 

EtheAv8r

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Jason, thanks for the detailed answer, I too have a KX3, which works very well, but I only rarely use it as I have too many other time consuming hobbies which take priority over making stuff. Your system would increase its usability enormously. I will look into constructing one.

I made some custom pully wheels for my local air target shooting club with it, each one took 15 hours with me standing over it with a small brush and lubricant. I had to turn it over and mill the other side, and then finish on the lathe. I did leave it on the mill once during a run to go to the loo, and came back to a broken end mill with the cutting edge completely encased in a rough ball ingot of aluminium, and the workpiece totally trashed.
 

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SmithDoor

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Hi Gielt,

The flash point for lubricating oil is around 225°C and for olive oil around 210°C so I wouldn't think that there is much of a serious problem there. There is however a problem when vegetable oils are used with cotton cloths. If saturated cloths are kept in bulk, say a waste bin, the heat generated by reactions between the oil and cotton is trapped in the container and can increase until combustion takes place spontaneously. I don't think that it is a problem with mineral oils.

Alcohol on the other hand has a flash point around 14°C hence the admonition not to smoke or strike a match when using but it is unlikely to combust otherwise but yes, a fireblanket within easy reach is the very minimum precaution.

I have had a workshop fire (electrical fault) and it is not a pleasant experience.

View attachment 139801
In full blaze

View attachment 139803

Aftermath. Both cars scrap as well.

Fortunately I had good, but expensive insurance which covered rebuilding and all contents luckily, but I am now extremely, perhaps overly cautious. Picture taken by a neighbour from his garden.

TerryD
They did put PCB in oil to stop fires. AKA transformer oil 🛢.

Dave
 

Wheat47

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I'll add my 2-bits worth.
I've been told that raw crude oil is a good lube/coolant, as it is high in sulphur.
I have a gallon jug of it, but I never used it because it smells so bad.
Perhaps gently brushing it on would work.
As far as removing chips, I've used a vacuum cleaner as I'm milling to suck up the chips.
Somewhere around here, I've got one of those air guns that sucks chips.
I like it because the business end is smaller and easier to get near the chips.
I see ads for using a refrigerated air nozzle.
Has anyone tried that? Does it work?

Jon
 

Toymaker

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I use a jet of low pressure air, typically under 10 psi, to both blow the chips away and to keep the end mill cool. Before I start milling I spray a toothbrush with a little WD-40 and bush it onto the end mill. For softer grades of aluminum, such as 6063, I will occasionally brush on a little more WD-40 during the milling process. You can see the white plastic air nozzle in this YouTube video starting around 3:40

 
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Jasonb

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EtheAr8r on a job like that I tend to get rid of a lot of the waste material on the first as it's often quicker then in Fusion put a dummy roughing cut in first so it thinks it has milled away that waste before doing the main adaptive and finishing cuts. So I would have either started with round stock or sawn and turned it round and then hollowed a lot out before going on the CNC.

Example here of initial turning and removing material between the spokes.



This one although not cutting aluminium shows how just a light flow of air around the 10psi mark will keep the cutter clear of swarf. Compare the initial adaptive cuts at the start of the video without air to those at 5mins 20 into the video where I have the air running. Non air swarf build up would be even worse if the roughing holes were not there to let most drop away.

 

Richard Hed

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I'll add my 2-bits worth.
I've been told that raw crude oil is a good lube/coolant, as it is high in sulphur.
I have a gallon jug of it, but I never used it because it smells so bad.
Perhaps gently brushing it on would work.
As far as removing chips, I've used a vacuum cleaner as I'm milling to suck up the chips.
Somewhere around here, I've got one of those air guns that sucks chips.
I like it because the business end is smaller and easier to get near the chips.
I see ads for using a refrigerated air nozzle.
Has anyone tried that? Does it work?

Jon
I see a lot of people blowing chips with an air gun where I would have vacuumed the chips first THEN give it a blow job
 

Jasonb

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I don't like to run my vacuum for several hours at a time, it makes a lot of noise and gets over heated. I can run with a constant small flow of air so my compressor just kicks in every 10mins or so
 

EtheAv8r

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Wow Jason, I found your videos very interesting, and really shows what the KX3 is capable of doing. I shy away from machining steel on mine as I have not idea of appropriate feeds and speeds to use on it. I have stumbled on some reasonable ones for aluminium by trial and error, and by using some from the wizards.

As you can no doubt tell, I am no engineer, just a keenish hobbyist who set up a workshop when I retired from 49 years in IT and who always tackled diy jobs and making stuff. I am definitely going to follow up on your air spray mist lubricant system.
 

Richard Hed

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I don't like to run my vacuum for several hours at a time, it makes a lot of noise and gets over heated. I can run with a constant small flow of air so my compressor just kicks in every 10mins or so
Yes, of course, what I am saying is do the cutting, then vacuum up the mess before blowing it clean. that way you get less chips jammed in the machine and you also have less sweeping up and dusting shelves and so on. I would never leave a vacuum on--too noisy
 
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