Machining Text

[mtechserv]

I need to machine text into an injection mold cavity. It only needs to be about 3/16" high and the font isn't important because the text is only for a date code.

What would be the best cutter to use for this job? I can turn 4500 rpm's on my CNC mill.

Any other advise for machining text would be greatly appreciated.

[Ken_Shea]

A ball mill works well.

Ken

[mishikwest]

We use single lip engraving cutters, made by Mirco 100 or Harvey tool.
.125" diameter with a 60deg. included angle. You can run them alot faster than a tiny endmill, and they leave nice crisp letters.

[mtechserv]

mishikwest,
What rpm are you running these at?

Originally Posted by mishikwest We use single lip engraving cutters, made by Mirco 100 or Harvey tool. .125" diameter with a 60deg. included angle. You can run them alot faster than a tiny endmill, and they leave nice crisp letters.

[mishikwest]

I've got machines with 6000k and 12000k, and they run fine at either rpm, I adjust the feed for each machine. About 18 imp for the 6000k spindles, and 30-40 imp on the faster machines. If cosmetics are important and really clean letters are needed, go even slower...for labeling jaws and whatnot, I run 50-60 ipm.

If you 've got 4500 rpm, I'd try around 10 ipm and see what things look like. The faster you go the "fuzzier" you letters will get, kinda like tear out. Flood coolant, for sure too. The nice thing about these engraving tools is that they won't really snap like a tiny endmill will (within reason), your letters will just start to look lousy.

oh, I've tried the .125 tools with the 30 degree included angle, but they don't seem to last as long as the 60 deg. ones. m2c

last but not least, I use the engraving function with Mastercam, which actually makes the tapered cutter "climb" out of each sharp corner, utilizing the decreasing radius of the cutter at the tip....Essentially trying to get a "zero radius" corner with the "zero radius" of the tip of the tapered tool. Sorta of the effect like chasing each crotch with a chisel to give it a crisp corner. For basic letters I'll just run a contour toolpath and drive the line of the letter with cutter comp off and no lead in or out.

hth