One of the more challenging jobs we’ve done this year was a mold core for a plastic injection customer. Material was P20 tool steel, pre-hardened to 30 HRC. The part had a lot of complex 3D contour work with some deep pockets and thin wall sections that made for some tense moments.
We ran this on a Makino V56 vertical machining center, using a 3D toolpath generated in Mastercam. Roughing was done with a 1/2″ 4-flute carbide end mill, then we stepped down through several semi-finish passes before going to a 1/8″ ball nose for the finish contours. Total machine time was right around 14 hours.
Surface finish on the cavity came out to about 32 Ra before polishing, which gave the customer’s polishing team a solid starting point. Part measured out on the CMM with all features within 0.001″. The customer had the mold running parts within a week of delivery. That kind of turnaround is why they keep coming back.