Farmer...
A 3D finish toolpath assumes that you have removed material, if needed, by a proper roughing toolpath. I prefer the Z level, with .100 (2.5mm) steps, .200 (5mm) stepover and a .040 (1mm) machining allowance using a 1/4" (6mm) end mill. I find it hard to imagine a properly setup finish toolpath would break bits if it followed a roughing, but if so, post a pic and the guys here can give you a strategy for success