RP Coated Shoulder Punches (Al-Cr Based + Alpha Treatment)

RP coated shoulder punches with an Al-Cr based coating and alpha treatment are used in injection mold tooling where punches face sliding contact, edge wear, and heat build-up during repeated cutting operations.

• Automotive electrical connector molds: Suited for trimming and piercing of conductive housings and small cross-sections, where punch edges experience abrasive wear from filled materials; the RP coating hardness and alpha adhesion help maintain performance under cyclic load.
• Appliance and industrial part molds: Effective for punching through tough thermoplastics and reinfoced blends, helping stabilize coating integrity so the punch retains sharpness longer and reduces changeover for tool maintenance.
• General-purpose precision punching cavities: Appropriate when conventional coatings delaminate or thin quickly; the alpha treatment is selected to improve film adhesion and wear behavior at the punch shoulder and tip transition.

Select this variant when durability is the limiting factor—specifically when wear at the tip/shoulder occurs faster than expected in your current mold design.

These shoulder punches are offered in multiple steel grades: SKH40 equivalent (powdered high-speed steel), SKH51 equivalent (M2), and SKD11 equivalent (D2). The RP coating is Al-Cr based and is engineered to provide high hardness and heat resistance for difficult punching.

• SKH51 (M2) option: Typically selected for a balance of wear resistance and toughness; best suited when you need stable cutting-edge behavior under heat.
• SKD11 (D2) option: Generally favors high wear resistance for abrasive cutting, with toughness trade-offs vs. high-speed steels in some conditions.
• SKH40 (powdered HSS) option: Used when controlled microstructure supports wear performance in repetitive punching.

The product also includes an alpha treatment to enhance coating film adhesion, improving resistance to coating breakdown and wear-through. Exact HRC and specific heat-treatment cycles are not listed in the provided specifications, so hardness should be confirmed against your configuration paperwork.

To select the correct RP coated shoulder punch, match the shank diameter D, tip geometry, and overall length to your mold core/cavity piercing requirement.

• Shank diameter D: choose within 3 ~ 25 mm. Use the specified shank tolerance +0.005/0, m5 to ensure correct sliding fit in the punch retainer or guiding bore.
• Tip dimensions: pick the tip shape (Round, Rectangle, Oblong, Double Flatted Round, Radius Rectangle) and then select P (1 ~ 18 mm) plus tip width/feature sizes (W 1 ~ 6 mm, with WC 1 ~ 3 mm when applicable).
• Lengths: select L from the provided ranges (e.g., 50 ~ 100, 60 ~ 100, 40 ~ 100, 70 ~ 100). Confirm full-length alteration LC (27 ~ 47 mm) and head thickness tolerance/total length alteration LCT / LMT (27 ~ 47 mm) for shoulder and stop depth alignment.

Ensure your punch-stroke design accommodates the altered head thickness (LCT/LMT) so the shoulder seats correctly without over-compression.