For smaller engravings on copper and silver, will it be ok to use a cooling spray on the carbide bit instead of cutting oil under the process? Are there anybody here who have tried that?
Printable View
For smaller engravings on copper and silver, will it be ok to use a cooling spray on the carbide bit instead of cutting oil under the process? Are there anybody here who have tried that?
I like using cutting must on the milling machine and the lathe. Makes way less mess and just as effective.
Hi,
with soft materials like silver and copper you may not need any cooling or even lubrication but clearing the chips away from the cutzone.
Recutting chips is a sure-fire way to get built-up-edge. Just blowing the chips away with a continuous air blast may be all you require.
Craig
Personally, when cutting copper and silver - we use straight oil - it doesn't take much flowrate, and it doesn't create as much smoke/mist in the work area unless you are running high spindle RPMs (>20k) - You can cut it with water base mist - but sometimes it will smear and leave marks. The oil keeps the soft materials from welding back together when cutting.
BTW - we use Hangsterfers HardCut NG - but you could probably use any decent grade mineral oil
The only thing you have to watch out for on copper is staining. A lot of oil based water soluble coolants will stain the copper as will some oils.
Hi,
Funny, but thats not what I've found, perhaps I just lucked out on the choice of water soluable oil.Quote:
The only thing you have to watch out for on copper is staining. A lot of oil based water soluble coolants will stain the copper as will some oils.
Some time ago I was making circuit boards but that had VERY thick copper layers, 420um thick, whereas normal 1 oz board has a 35um
layer. In order to do this I used 0.5mm endmills as regular V-bits lead to an unacceptable trace thinning. To get any sort of useful life
from such small diameter tools in a proportionately (420/500=84%) thick material I used flood coolant.
Naturally I added some water soluable oil, and I got some locally, Total Lactuca LT3000, and it worked fine without any staining.
As it turns out I'm now of the opinion that the oil is actually a small part in the sucess and I now attribute the success I had to the
removal of chips from the cutzone. While I used flood cooling by directing a moderately powerful stream into the cutzone I have susequently
found that a continuous air blast into the cutzone works nearly as well.
With soft and 'gummy' materials like copper and silver and certain near pure aluminums if a chip is re-cut its propensity to 'weld' itself
to other chips, the tool or the base material is huge. If you eliminate the re-cutting of chips you can go form a 5% sucess to 95% just
like that. That was certainly my experience with cutting the thick copper boards I was making.
Craig