Fixed Die Half (Cover Die): Component Specs, Materials & Applications

Component Specifications

Definition

The Fixed Die Half, also known as the Cover Die or Stationary Die, is the non-moving component of a die casting die assembly. It is securely mounted to the stationary platen of the die casting machine and contains the cavity side of the mold. This half typically houses the sprue bushing, through which molten metal is injected, and may incorporate cooling channels, ejector pin holes, and alignment features. It remains fixed during the casting cycle while the moving die half opens and closes against it.

Working Principle

The Fixed Die Half provides a stable, stationary mold surface against which the Moving Die Half closes to form the mold cavity. Molten metal is injected through the sprue in the fixed half into the cavity. After solidification, the moving half retracts, while the fixed half remains in place, allowing the casting to be ejected from the moving half. Its rigidity ensures dimensional accuracy and consistent alignment during high-pressure injection cycles.

Materials

Typically made from premium tool steels such as H13 (AISI), DIN 1.2344, or similar hot-work steel grades. Heat treated to 44-48 HRC for durability. Alternative materials include maraging steels for high-volume production or copper alloys for improved thermal conductivity in specific applications.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Alignment	Precision guide pins/bushings (e.g., 40-60 mm diameter)
Thickness	200-600 mm (varies with die size)
Surface Finish	0.4-1.6 μm Ra on cavity surfaces
Weight Capacity	Designed for machine clamping force (e.g., 250-4000 tons)
Cooling Channels	Diameter 8-12 mm, conformal or drilled
Mounting Pattern	Standardized per machine platen (e.g., JIS, DIN, or custom)

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 12165, DIN 16760, NADCA #207-2003

Parent Products

This component is used in the following industrial products

Die Casting Die

A precision tool used in high-pressure die casting to shape molten metal into complex components.

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Engineering Analysis

Risks & Mitigation

Thermal fatigue cracking
Wear on guide surfaces
Cavity erosion from molten metal
Misalignment due to platen deflection
Cooling channel blockage

FMEA Triads

Trigger: Cyclic thermal stress from molten metal injection
Failure: Heat checking or thermal fatigue cracks on cavity surface
Mitigation: Use H13 steel with proper heat treatment, implement conformal cooling, and apply surface treatments (e.g., nitriding).

Trigger: Improper alignment or worn guide pins/bushings
Failure: Flash formation, part dimensional inaccuracies, or die damage
Mitigation: Regular inspection and replacement of alignment components, use of hardened steel guides, and proper lubrication.

Trigger: Inadequate cooling or channel blockage
Failure: Extended cycle times, incomplete solidification, or warped castings
Mitigation: Design optimized cooling layouts, use filtered coolant, and perform routine maintenance.

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.05 mm on critical dimensions, flatness within 0.02 mm per 100 mm

Test Method

CMM inspection, hardness testing (Rockwell C), dye penetrant testing for cracks, pressure testing of cooling channels

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

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Manufacturers of Fixed Die Half (Cover Die)

Manufacturer profiles associated with Fixed Die Half (Cover Die).

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Frequently Asked Questions

What is the difference between Fixed Die Half and Moving Die Half?

The Fixed Die Half is mounted to the stationary platen and remains in place during operation, containing the sprue and often the cavity. The Moving Die Half is mounted to the moving platen, opens/closes, and typically contains the ejector system to remove castings.

Why is H13 steel commonly used for Fixed Die Half?

H13 tool steel offers excellent hot hardness, thermal fatigue resistance, and toughness at elevated temperatures, making it ideal for withstanding repeated thermal cycling and high-pressure injection in die casting.

How is alignment maintained between die halves?

Precision guide pins and bushings are installed in the Fixed Die Half to ensure accurate, repeatable alignment with the Moving Die Half, preventing flash and ensuring part dimensional consistency.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Fixed Die Half (Cover Die)