M2 (SKH51) High-Speed Steel Thread Cores

Mirror Polished Mold Inserts for High-Cavity Injection Molds

Product Overview

Our M2 (SKH51) high-speed steel thread cores are precision mold inserts designed for high-wear and high-cycle injection molding applications.

These thread cores are primarily used in:

• Cosmetic cap molds

• Packaging closure molds

• Medical threaded components

• High-speed multi-cavity injection molds

Manufactured from hardened M2 / SKH51 high-speed steel and finished with mirror polishing, these cores deliver excellent wear resistance, stable thread geometry, and smooth demolding performance.

All components are produced strictly according to customer drawings (Built-to-Print).

Material – M2 / SKH51 High-Speed Steel

M2 (SKH51 equivalent) is selected for:

• High hardness capability

• Excellent wear resistance

• Good dimensional stability

• Resistance to thread edge rounding

Typical hardness range after heat treatment:

60–62 HRC (customizable upon request)

Compared to standard H13, SKH51 offers higher hardness and improved wear life in threaded applications.

Typical Applications

These precision thread cores are widely used in:

• Cosmetic caps

• Flip-top closures

• Bottle screw caps

• Medical packaging closures

• Small precision threaded plastic parts

Especially suitable for 16 / 32 / 48+ cavity cap molds requiring long production runs.

Engineering Focus

Thread cores directly affect:

• Cap torque performance

• Thread engagement accuracy

• Demolding smoothness

• Mold maintenance interval

Key technical priorities include:

1) Thread Profile Accuracy

• Controlled pitch and flank angle

• Consistent minor and major diameters

• Tight tolerance on functional thread surfaces

• Precision turning and grinding for thread stability

Machining tolerance can reach ±0.002 mm depending on geometry.

Uniform thread geometry ensures stable engagement torque across cavities.

2) Mirror Polished Surface

Mirror polishing:

• Reduces friction during demolding

• Minimizes resin adhesion

• Improves thread surface appearance

• Extends mold service life

Surface roughness can be improved to fine Ra levels depending on application.

3) Multi-Cavity Consistency

For high-cavity molds:

• Thread cores are batch-machined

• Grinding processes are controlled for repeatability

• Dimensional matching across cavities is verified

This reduces torque variation and improves cap interchangeability.

Manufacturing Capability

Production processes include:

• CNC turning for thread forming

• High-speed CNC machining

• Precision grinding after heat treatment

• EDM for complex profiles

• Mirror polishing finishing

All cores are heat treated before final precision finishing to ensure dimensional stability.

Quality Control

Each thread core undergoes:

• Raw material verification

• Heat treatment hardness testing

• Dimensional inspection

• Thread profile verification

• Final inspection before shipment

Inspection documentation available upon request.

OEM / Built-to-Print Manufacturing

We support:

• Manufacturing from 2D / 3D files (STEP, IGS, X_T, etc.)

• Custom thread standards

• Replacement cores for existing molds

• Small batch trials and volume production

• Long-term spare parts supply

Strictly produced according to customer technical specifications.

Related Products

To support complete cap mold systems, we also supply:

• H13 thread cores

• Precision cavity inserts

• Core pins and sleeve pins

• Multi-cavity mold components

• Hot runner compatible inserts

All components are designed for compatibility within cap mold assemblies.

Technical FAQ

Q1: Why choose SKH51 instead of H13 for thread cores?
SKH51 provides higher hardness and better wear resistance for high-cycle threaded applications.

Q2: Is mirror polishing necessary?
Mirror polishing reduces friction and improves demolding performance, especially for cosmetic cap molds.

Q3: Can thread cores be matched across 48+ cavities?
Yes. Controlled batch machining ensures consistent geometry across cavities.

Q4: Can custom thread profiles be produced?
Yes. All thread standards can be manufactured according to drawings.

Request a Technical Quotation

To receive a quotation, please provide:

• Thread profile drawing

• Material specification

• Cavity quantity

• Surface finish requirement

• Target production volume

• Delivery timeline

Our engineering team will review your specifications and provide a detailed manufacturing proposal.