Machining Applications Views: 12

For mold machining we recommend cobalt HSS (HSS-E) countersinks: 1) Mold steel is hard (pre-hardened HRC30-40, hardened HRC45-60) - standard HSS wears fast; cobalt HSS has good red hardness and wear resistance; 2) Molds need smooth surfaces - cobalt HSS cuts stably with good finish; 3) Many mold materials - 718, P20, S136, SKD11, Cr12MoV etc. - cobalt HSS suits them all. Tips for chamfering mold steel: 1) Pre-hardened (HRC30-40) - cobalt HSS, 600-1000rpm, feed 0.08-0.15mm/rev, with cutting fluid; 2) Hardened (HRC45+) - carbide or coated cobalt HSS, 200-500rpm, feed 0.03-0.08mm/rev, generous cutting fluid; 3) Finishing - take a final light pass with no feed (one idle revolution) for a smoother surface; 4) Avoid chipping - mold steel is hard; do not overspeed or overload; re-sharpen dull edges promptly; 5) Mirror finish - for mirror-required mold chamfers use a sharp new tool, low speed, small feed, then hand-polish with sandpaper or an oilstone.