Single-Stepped Shoulder Punches - DLC Coating

This type of single-stepped shoulder punch is used inside close-tolerance die sets where the punch must remain precisely guided throughout repetitive strokes. The DLC (XCD) surface finish is especially suited to applications that demand clean, controlled action with minimized metal-to-metal friction and wear.

• Automotive connector and sensor housings: In multi-cavity progressive tooling, the stepped shoulder helps maintain consistent positioning between tool sets, while the DLC coating supports long production runs by reducing wear on the working surfaces.
• Electrical terminal and contact forming: When punching and piercing operations require stable stroke-to-stroke repeatability, the shoulder geometry provides reliable alignment; the low-friction coating helps prevent galling during high-cycle output.
• Precision brackets and enclosures: For part features with tight dimensional control, the guided shank behavior supports repeatable piercing, and the DLC finish improves tool surface longevity under sliding contact.

These punches are offered in two high-speed steel (HSS) options with different performance balances: SKH40 Equivalent (powdered HSS) and SKH51 Equivalent (M2). SKH51 (M2) is typically selected for higher wear resistance and hot hardness characteristics, while SKH40 (powdered) can offer improved uniformity and edge stability for demanding cycles.

The DLC (XCD) coating adds a hard, low-friction layer that reduces tool-to-work friction and helps limit abrasive/adhesive wear at the contact surfaces. Heat treatment is specific to the supplied HSS grade and punch design; the intent is a hardened, wear-capable HSS base followed by DLC deposition to further protect the working geometry.

• Hardness/behavior: Choose HSS based on wear vs. toughness needs—higher wear resistance can slightly reduce toughness margin depending on the chosen HSS grade and resulting hardness.
• Trade-off: DLC improves surface wear behavior, but ultimate resistance still depends on the hardened HSS substrate and the load/impact conditions of the punch operation.

Selection starts by matching the punch shank diameter D and overall length to the die holder and guide requirements. Available shank diameters are 3 to 25 mm, and the D tolerance is +0.005/0, m5, so the punch fit should be specified against the corresponding guide/bore tolerance to avoid binding while maintaining positional stability.

• Choose head/tip dimensions: Tip shapes include round, rectangle, oblong, double flatted round, radius rectangle. Tip length variants use B values labeled L, S, X, and tip dimension alteration ranges include P = 1 to 18 and PC = 1 to 9, with tip dimension ranges such as W = 1 to 6 and WC = 1 to 3.
• Match length and shoulder geometry: L (L dimension) is offered in groups such as 50–100, 60–100, 40–100, and 70–100 mm. Full length alteration LC and head-thickness/total-length change ranges are provided as 27 to 90.1 mm, which directly affect how the shoulder seats within the die set.
• Guidance: Use the selected LC and thickness-change parameters (LCT/LMT ranges) to ensure the head thickness and total length align with cavity/core stroke depth and clearance.