Zamak Die Cast Inserts for Overmolding
We manufacture the rigid core of your hybrid zamak-rubber and zamak-plastic components
Zamak inserts designed for overmolding
If your company produces gaskets, technical rubber articles or overmolded plastic components, you know how critical the quality of the metal insert is. An imprecise insert means gaskets that leak, primer that does not adhere, and production rejects.
Micrometal manufactures zamak die cast inserts specifically designed for overmolding. We handle everything related to the metal part — from co-design to tooling, from die casting to finishing — delivering an insert ready for your rubber, silicone or plastic overmolding process.
Why zamak is ideal as an overmolding insert
Compared to other metals used as overmolding inserts, zamak offers concrete advantages that translate into fewer rejects and lower costs for your production process:
- Tolerances of ±0.05 mm directly from the mould — the gasket seat is perfect, with no secondary machining required. This means the rubber sits exactly where it should, with no gaps.
- Excellent surface finish — the smooth, uniform surface of die cast zamak ensures better primer adhesion and more reliable rubber vulcanisation on the insert.
- Complex geometries in a single shot — undercuts, anchoring grooves, flow channels, knurling: everything is produced directly during casting, eliminating costly secondary operations.
- Lower cost than aluminium or steel — moulds lasting 750,000 to 2,000,000 shots (10 times more than aluminium), faster production cycles, lower energy consumption.
- Corrosion resistance — no oxidation problems under the rubber, even in humid environments or in contact with fluids.
How we design your overmolding insert
Our approach starts from the finished component — your rubber-metal part — and works backwards to optimise the zamak insert:
- Drawing analysis — We study your finished component (rubber + metal) to understand sealing areas, mechanical stresses and dimensional requirements.
- Insert design — We define optimal anchoring geometries: undercuts for mechanical rubber locking, grooves for material flow during overmolding, surfaces prepared for chemical adhesion.
- 3D prototyping — We produce 3D printed prototypes of the insert to validate the fit with your overmolding tool before investing in the final mould.
- Series production — Die casting with 100% dimensional control, surface finishing (degreasing, sandblasting) and delivery of inserts ready for your process.
Compatible elastomeric materials
Our zamak inserts are compatible with all major elastomers and plastics used in industrial overmolding:
- NBR — for applications in contact with oils and hydrocarbons (valves, pumps)
- EPDM — for water, steam and weathering (taps, outdoor)
- FKM / Viton — for high temperatures and aggressive chemicals (automotive, industrial)
- Silicone (VMQ) — for food-grade, medical and high-temperature applications
- TPE / TPU — for flexible plastic without vulcanisation (handles, ergonomic grips)
- Nylon, POM, ABS — for overmolding with rigid plastics (connectors, housings)
The zamak alloys we use — ZP3 for general applications and ZP5 for greater hardness and mechanical strength — are both ideal for overmolding.
Sectors where we supply overmolding inserts
- Gas valves and regulators — zamak bodies and levers with integrated NBR or FKM sealing gaskets
- Taps and fittings — cartridges, knobs and components with O-rings or perimeter gaskets
- Automotive — waterproof connectors, anti-vibration mounts, IP-rated components
- Locks and security — handles with ergonomic rubber grip, sealed mechanisms
- Home appliances — components with IP65/IP67 sealing, knobs and controls
- Electronics — EMI shielded housings with overmolded perimeter gasket
Technical specifications
- Available alloys: ZP3 (ZnAl4), ZP5 (ZnAl4Cu1)
- Insert weight: 15 g to 700 g
- Tolerances: ±0.05 mm from the mould
- Surface preparation: degreasing, sandblasting, primer-ready
- Production capacity: 75,000 kg/month, 11 hot chamber presses (25-90 t)
- Certification: ISO 9001
- Prototyping: 3D printing for pre-series validation
Do you produce gaskets or rubber articles?
Send us your finished component drawing and we will design the optimal zamak insert for your overmolding process.