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Engraving with .015" ball endmill

pgmrmike

Hot Rolled
Joined
Jun 24, 2010
Location
Plantersville, TX
I have a job that calls for engraving a logo, PO etc. I have engraved before but usually use a centerdrill or 1/16" etc ball nose em etc. The customer is very specific in what they want on this part. It calls out a .015" ball nose end mill, .01" deep. I have never used an end mill this small on anything. Recommended speeds and feeds ( best I can tell from several sources )are .00004" per tooth, .003-.03" DOC ( full slotting ).

Tool: 4 flute Altin coated .015" ball stub
Machine max RPM is 8000 but I usually run 6000 max
Material: 8620 soft

So, if I run 6000 ( which is way to low sfm of course ) that ends up at .96 IPM and 3 passes.

Does sound right? Seems crazy slow. At a .003" DOC I would be getting some chip thinning and it seems like the feedrate should be higher. (I do this with larger EMs but... )


Any advice would be appreciated.
 
I think I would try a regular single flute engraving tool with the .0075 radius ground on the end. It would be a lot stronger than a ball end mill.
 
buy extra end mills, they break easy

Thats what I am worried about. Im scared to look at em wrong :ill:


I think I would try a regular single flute engraving tool with the .0075 radius ground on the end. It would be a lot stronger than a ball end mill.

I thought about that but at .01" deep thats above the radius. All the engravers I have seen go from radius to an angle. That would make it too wide at the top.
 
I have a job that calls for engraving a logo, PO etc. I have engraved before but usually use a centerdrill or 1/16" etc ball nose em etc. The customer is very specific in what they want on this part. It calls out a .015" ball nose end mill, .01" deep. I have never used an end mill this small on anything. Recommended speeds and feeds ( best I can tell from several sources )are .00004" per tooth, .003-.03" DOC ( full slotting ).

Tool: 4 flute Altin coated .015" ball stub
Machine max RPM is 8000 but I usually run 6000 max
Material: 8620 soft

So, if I run 6000 ( which is way to low sfm of course ) that ends up at .96 IPM and 3 passes.

Does sound right? Seems crazy slow. At a .003" DOC I would be getting some chip thinning and it seems like the feedrate should be higher. (I do this with larger EMs but... )


Any advice would be appreciated.

tool runout even if .001" for small end mills makes the feed and speed recommendations inaccurate.
.
bigger tool can absorb a lot of abuse but they little ones are often gone with no warning in a second
.
make sure you got spare end mills
 
I've tried this before with a .015625 endmill and your number sound about right. It was horribly slow and I broke a handful of end mills. It seemed like they broke on the plunge.

I finally convinced the customer that a 1/32" ball endmill .005 deep was a much more economical way to go. That has been my go to for fine engraving for years now.
 
Work up two quotes... one with their .015" ball .010" deep, and one with a .031" ball .005" deep like above (my preference is .003" deep). Ask which one they want to use.

Either way, runout and coolant coverage are very important for tool life for this. Without coolant, or at least air blast, chips from this type of operation with tools this small seem to just sit there around the tool.
 
.003 cut per pass sounds way to deep for my taste, I would go half that at about 15" feed.. I do allot of this in hard material.. I run same size ball 25k at .002 deep per pass about 35" feed.
 
Use a single flute engraving cutter they are much much stronger, and made for the job - right down at the nitty gritty end engraving is quite different to milling. ........I'd be VERY surprised if you couldn't find an engraving cutter to match your spec.
 
I'd go with a runner cutter as suggested above, but look in the Harvey catalog. They make one with a .01" radius on a 20 or 30 degree included angle body. That's so close to your customers spec that I'll bet they can't tell any difference. Quite a bit tougher than a ball mill.
 








 
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