Re machining ti with no coolant

[pugga]

Hey guys,

I have been thinking about machining/milling into some Ti but am not able to have coolant flowing like I have seen in person and videos. I was wondering if I make the depth of cut very small ie .05mm and just do more passes to get the required depth would that be possible. I can have cold air blowing on the piece but thats about it. Any input would be greatly appreciated.

Cheers pugga

 

[precisionworks]

I can have cold air blowing on the piece

On a fully exposed cut (like a milling pass that's shallow) cold air works well - I use an Exair Cold Air Gun for exactly that purpose. Same with turning on the lathe - if the air coolant can be directed at the point of contact between tool & work it can be effective.

Liquid coolant is better & you may want to use a trigger spray bottle as the tool cuts deeper into the work. You can't use too much coolant with either Ti or stainless.

 

[Anglepoise]

I use a product when cutting Ti, called 'Anchorlube'.

It is water soluble and the consistency of thin grease. It does not smell
even when hot or smoke. It is a great product when flood coolant is not an option.

Goes on with a brush and acts as a lube as opposed to a coolant.

It definitely extends tooling life and might work well with air cooling.

 

[pugga]

Interesting, thanks for the input. I have a 2mm end mill on its way but because of the lack of coolant wasn't sure if it could do what I wanted. I don't care how many passes it takes to reach between 2.1mm-2.2 mm deep (sorry not sure of imperial measurements). I will test on quite a few scrap pieces before getting the courage to do the real things:sick2:. I will see if there is an equivalent to Anchorlube here in Australia.

Cheers pugga

 

[McGizmo]

I am by no means any expert like others here are but I have found that a good mister is viable and not the mess you get from a real coolant flow. I have also had some success using one of the new micro drop coolants that are designed to be used with measured dispensers which I did not purchase. I just have it in a syringe and apply drops to the cutting tool as I feel warranted. These comments all relate to turning and not milling. I have a cold air gun as well but it keeps my compressor running a lot and I would rather not subject myself or neighbors to the noise.

 

[TranquillityBase]

Interesting, thanks for the input. I have a 2mm end mill on its way but because of the lack of coolant wasn't sure if it could do what I wanted. I don't care how many passes it takes to reach between 2.1mm-2.2 mm deep (sorry not sure of imperial measurements). I will test on quite a few scrap pieces before getting the courage to do the real things:sick2:. I will see if there is an equivalent to Anchorlube here in Australia.

Cheers pugga

That's a pretty small cutter (diameter).....If it's a carbide cutter?...flood it (unbroken stream), or run it dry. Carbide doesn't like interrupted, cold (room temp, or colder) coolant intermittently spritzed on.

Experimenting with speeds and feeds will net the best results, coolant or no coolant. Have fun

 

[fyrstormer]

This makes me wonder, what about having a submerged lathe with the piece being machined sitting completely underwater and the cutter bit reaching down under the surface of the water to do its work? It shouldn't splash as long as the shank of the bit is smooth at the spot where it breaks the surface of the water.

Obviously this would require some heavy-duty seals around rotating parts, but it would provide unparalleled cooling capacity for both the bit and the workpiece. it would also trap all the debris underwater, where it would just settle out instead of flying around in the air.

 

[65535]

Just need sealed stepper motors rated for submersion. A lot more work than it's worth I reckon.

 

[pugga]

Thanks for the responses and yes my questions relate to a small CNC milling machine that has no cooling systems as its not really supposed to do what I am trying to do with Ti:devil:. In the past when cutting some 2.1mm x 6mm slots in Al with a 2mm end mill we have just used WD40 or similar. I found a product here called Boelube (similar to Anchoelube I guess) that sounds promising. Combined with cold air and very small depth increases (.05mm) I think I will give it a go with some SS and see how it goes. I will have to experiment with spindle speeds (for Al I run it at around 6000rpm) also as I have read about not letting the cutting edge rub as it makes the Ti harder. I also have to think about X and Y axis speeds:thinking:. Sounds like fun. Cheers pugga

 

[Anglepoise]

What every you do, keep in mind that TI work hardens just by looking at it.<G>

So tooling must be sharp, and if you take small cuts, keep the feed up.

 

[precisionworks]

I will have to experiment with spindle speeds

About 150 sfpm is what you want. That's 7350 rpm at 2mm diameter. FWIW, aluminum is normally cut at 1000 to 2000 sfpm.

if you take small cuts, keep the feed up.

+1

Feed as fast as possible. It's easy to tell when you're feeding too fast - the tool breaks - so feed just slightly slower than that.

I have a 2mm end mill on its way

On a new job like this, in a workhardening material, you'll probably want a few extra tools on hand.

 

[Tom Anderson]

Except for tapping, I don't use any coolant when machining titanium. (I use a little air to clear the chips away, but that's it.)

My advice would to buy several end mills and practice on some excess titanium. Using the same grade of material as the production part is highly recommended because different titanium alloys can require different speeds and speeds.

In any case, you'll need to be careful with a ø2mm end mill. I use 1/16" carbide ball end mills frequently and they are rather fragile.

 

[cmacclel]

I run 6al-4v at 150 SFPM @ 0.008-0.010 IPM roughing and 175 SFPM @ 0.003 for finishing.

Mac