Cold Heading Mould: Characteristics, Applications, and Maintenance

What is Cold Heading Mould?

Cold heading mould, also known as cold forming dies, is a specialized tooling system used in cold heading processes to form metal parts at room temperature through plastic deformation. These moulds are engineered to withstand extreme pressures (up to 2,500 MPa) while maintaining precise dimensional tolerances (±0.01 mm). The typical service life ranges from 100,000 to 5,000,000 cycles depending on material and application.

Application Scenarios

Cold heading moulds are extensively used across multiple industries where high-volume precision metal components are required:

1. Fastener Manufacturing

Produces bolts, screws, and rivets with production speeds reaching 400-600 pieces per minute. Capable of forming complex head geometries including hex, torx, and custom profiles with ±0.05 mm positional accuracy.

2. Automotive Components

Manufactures precision parts like valve retainers, bearing races, and transmission components. Modern cold heading moulds can form high-strength alloys (up to 1,200 MPa tensile strength) while maintaining 95-98% material utilization.

3. Electrical Connectors

Creates contact pins and terminals with micron-level precision (±0.003 mm for critical dimensions). Specialized mould designs accommodate multi-stage forming of complex geometries in materials ranging from copper alloys to nickel silver.

4. Aerospace Fasteners

Produces high-specification fasteners meeting NAS, MS, and AN standards. Moulds for aerospace applications often feature enhanced coatings (AlCrN or DLC) to extend tool life when working with titanium and Inconel alloys.

5. Medical Implants

Forms bone screws and orthopedic fasteners from biocompatible materials like Ti-6Al-4V and 316LVM stainless steel. Medical-grade moulds achieve surface finishes below Ra 0.05 μm to prevent micro-crack initiation.

Maintenance Procedures

Proper maintenance is critical for maximizing cold heading mould performance and longevity:

1. Cleaning Protocol

• Perform ultrasonic cleaning every 50,000 cycles using specialized Solutions (pH 7.5-8.5)

• Remove residual lubricants with non-chlorinated solvents (flash point > 60°C)

• Inspect for micro-cracks using 10x magnification after cleaning

2. Lubrication Management

• Apply high-pressure lubricants with viscosity 60-80 SUS at 40°C

• Maintain lubricant filtration to 5 μm particle size

• Monitor lubricant pH (8.0-9.5) to prevent corrosive wear

3. Wear Monitoring

• Measure critical dimensions every 25,000 cycles using CNC CMMs (0.5 μm resolution)

• Track edge radius wear (replace at R0.1 mm for most applications)

• Implement profilometry to detect surface roughness changes beyond Ra 0.4 μm

4. Storage Conditions

• Store in climate-controlled environments (20±2°C, 40-50% RH)

• Use VCI (Vapor Corrosion Inhibitor) paper with 0.05-0.1% nitrite content

• Apply rust-preventive oils with 0.2-0.3 mm coating thickness

5. Reconditioning Procedures

• Perform EDG (Electro-Discharge Grinding) for worn profiles (0.02 mm maximum removal per pass)

• Reapply PVD coatings at 400-450°C substrate temperature

• Conduct cryogenic treatment (-196°C for 24 hours) to relieve stresses