Defense Industry Molds and Precision Parts Manufacturing

For defense industry parts, the material is defined in the technical specification and on the drawing; equivalent materials can only be used with customer approval. Commonly encountered materials include:

• Aluminium alloys: 7075-T6 and 6061-T6 for lightweight, high-strength housings, brackets and mounting parts. Alloys such as EN AC-46000 (AlSi9Cu3) and EN AC-44300 (AlSi12) for pressure die-cast parts.
• Steels: 42CrMo4 and similar quenched and tempered steels; precipitation-hardening stainless steels such as 17-4PH (1.4542).
• High-performance plastics: PA66 GF30/GF50 for structural parts; PPS GF40 and PEI for high-temperature and flame resistance; PEEK for applications requiring wear and chemical resistance.
• Impact-resistant plastics: PC and PA12 for enclosures and covers that require toughness at low temperatures.
• Elastomers: TPE and TPU for grip surfaces and sealing elements.

Polymers such as PPS, PEI and PEEK are processed at mold temperatures of approximately 130–200 °C. This calls for a thermally insulated mold design and hardened steels such as 1.2343 (48–52 HRC) that maintain dimensional stability at high temperatures.

In defense projects, mold design is structured around low-to-medium-volume production that nonetheless demands high reliability. At the design stage, specification requirements and manufacturability are evaluated together.

• DFM and specification compliance: Wall thickness, draft and corner radii are agreed with the customer so as not to affect critical dimensions or mechanical strength; if a drawing change is needed, written approval is obtained.
• Flow and structural evaluation: In glass-fiber-filled parts, fiber orientation and keeping weld lines away from load-bearing areas are critical.
• Interchangeable inserts: Cavities are designed with modular inserts for rapid adaptation to variants and revisions.
• Metal insert molding: Metal components such as threaded bushings, connecting pins and terminals are embedded in the plastic.
• High-temperature molds: Heating elements, insulation plates and thermal expansion allowances are built into the design.

For projects requiring confidentiality, care is taken to handle CAD data within the framework of the non-disclosure agreement (NDA) signed with the customer and with restricted access.

For defense industry parts, surface requirements are mostly tied to function, coating compatibility and needs such as low light reflection.

• Matte surfaces: To reduce light reflection, an EDM finish in the VDI 3400 30–36 range or a fine texture applied to the mold surface is preferred for enclosures and covers.
• Grip surfaces: Non-slip textures or TPE overmolding are used on hand-operated parts such as grips, buttons and covers.
• Pre-coating surfaces: On aluminium parts to be anodized, chromate conversion coated or painted, the machined surface roughness (e.g., Ra 1.6 µm) and edge chamfers determine coating quality.
• Optical and transparent parts: Display and window parts require an SPI A1–A2 polish and a mold steel with a correspondingly high degree of cleanliness.

Surface requirements are verified together using reference plaques, approved samples or the customer's standard. Machining dimensions are determined taking into account the dimensional change after coating.

Tolerances on defense parts are typically tight and contractually binding. Every dimension and geometric tolerance (ISO 1101 or ASME Y14.5) defined on the drawing must be measurable and reported.

In glass-fiber-filled materials, differential shrinkage depending on flow direction is the biggest challenge for tight-tolerance plastic parts. Critical dimensions are therefore produced with the mold built steel-safe, and the target dimension is approached in a controlled manner based on T1 measurement results. Flatness and warpage limits should be defined separately for sealing surfaces. For parts to be coated, the coating thickness is taken into account when determining machining dimensions. Measurement results are reported with the nominal value, tolerance and actual value for each characteristic.

In the defense industry, low-volume, high-complexity parts and prototypes that do not justify a mold investment are mostly CNC machined. CNC machining plays two roles in this sector: direct part production and mold manufacturing.

• Direct part production: Aluminium housings, mounting plates, brackets and fasteners are machined from solid stock; machining strategies that reduce stress and vibration are applied to thin-walled parts.
• Turning: Shafts, bushings, pins and threaded connectors are produced with precise diameter and thread tolerances.
• EDM: Narrow slots and sharp internal corners in hardened steels are machined by sinker or wire EDM.
• Mold manufacturing: Cavities, cores and inserts are programmed with CAD-CAM and verified by simulation.

The program, tooling and fixture information used for each part is recorded, so that the same process can be replicated exactly on repeat orders. This discipline supports the configuration management and traceability requirements expected in defense projects.

In defense projects, sample approval is the contractual starting point for series production. Trial and first article processes are therefore carried out with full documentation.

• T0 and T1 trials: For molded parts, filling, ejection and insert positions are checked; T1 samples are submitted with a full dimensional report.
• First article inspection (FAI): Every characteristic on the drawing is measured and reported individually using a numbered (ballooned) drawing.
• Process parameters: Approved injection or machining parameters are frozen; if a change is needed, the customer is notified and approval is obtained.
• Functional and assembly tests: On request, samples are tested in the customer's assembly; the feedback is incorporated into mold corrections.

Parameters specific to high-performance polymers, such as material drying conditions, melt temperature and mold temperature, are recorded during trials and turned into series production work instructions. During series production, parts taken at defined intervals are compared with the approved sample.

In the defense supply chain, quality is built on measurable results, complete documentation and batch-level traceability. We work with records and reports aligned with the processes of customers who require quality standards such as AQAP 2110 or ISO 9001 from their suppliers.

• Dimensional reports: All dimensions are reported against a ballooned drawing; CMM measurement is established industry practice for complex geometries and can be included in the inspection plan.
• Material certificates: EN 10204 3.1 certificates are supplied for metal raw materials, and manufacturer lot certificates of analysis (CoA) for plastic resins.
• Traceability: Raw material lot, production date, the mold or CNC program used, and inspection records are linked together.
• Nonconformance management: Deviations are recorded; nonconforming product is not shipped without customer approval.

Depending on order requirements, a Certificate of Conformance (CoC) and inspection reports are shipped with the parts. Confidentiality and information security requirements are defined together with the customer at project kickoff.