303SS V cutting issues

[zcases]

I am cutting some 303. I am leaving raised text and trying different V shaped cutters to get fine detail.

I am cleaning out the flat areas with a 1/4 carbide and not having many issues with that. I didnt think the 303 would exhibit the hardening issues like 304/316.

But I am struggling with the 60 degree V cutter. I am using carbide engraving cutters from Harvey Tool, the half round style. Maybe I will try an end mill with a 60 degree tip, or a 2 flute engraver.

So, the problem - tip of the tool breaking. I only have 3500 rpms available on my mach 2 retrofitted Boss5. I will keep experimenting, but man these cutters are getting expensive. I have been trying 9ipm and 3250 rpm. I may also try to clean out more material with a different roughing strategy. But I suppose I am looking for some advice.

Anyone?

[BobWarfield]

Found this feeds and speeds page for v-cutters:

http://www.2linc.com/engraving_assis...eds_speeds.htm

Trying to plug their parameters into G-Wizard (they don't exactly say SFM and IPT figures, but I fudged it), I think you're feeding too fast.

I would try more like 2 IPM at that spindle rpm and see how that works.

Cheers,

BW

[Chrliev]

You are spinning too slow and feeding too fast. Using carbide your feed should be about .0002 per RPM per cutting flute, any higher load and you will break the tool tip.

Cutting tools offer 2 scenarios hardness or toughness and its important to understand the difference.

Since you can't spin any faster you have to look at the alternative to carbide. Carbide is great for wear because its hard but its low on the toughness scale. You need a hard tool when you are spinning fast and a tough tool when spinning slow, you are spinning to slow so you need a tougher tool.

My recommendation is to use a HSS or M42 cobalt tool, that is tough and will take the hammering better than a hard and brittle carbide tool. The other advangtage in using HSS is HSS tools are cheaper.

I hope this helps you...