Insert Moulding Technology
Insert moulding combines metal and plastic in a single production step, creating hybrid parts with the mechanical strength of metal and the design freedom of plastics. This project involved moulding ABS around brass threaded inserts for an electromechanical housing, eliminating the need for post-mould assembly.
The inserts are placed in the mould manually or by robot, then overmoulded with ABS. The plastic flows around knurled features on the insert, creating a mechanical interlock that withstands pull-out forces exceeding 500N.
Material Compatibility
ABS was selected for its excellent adhesion to metal substrates and dimensional stability. The moulding temperature (240°C) is sufficient to flow around insert features without damaging brass or steel components. For higher temperature applications, we use PC/ABS blends or PBT.
Insert materials we process: brass, stainless steel, aluminium, copper, and specialty alloys. Pre-heating inserts to 80-120°C before moulding reduces thermal shock and improves bond strength.
Mould Design for Insert Moulding
The mould incorporates precision locating pins and magnets to position inserts within ±0.05mm. A sensor verifies insert presence before the mould closes, preventing expensive damage from empty-cavity shots. The cavity design includes overflow wells to accommodate insert dimensional variation.
Process Control
Insert moulding requires tighter process control than standard moulding. We monitor cavity pressure directly to detect insert misalignment or absence. Injection speed profiling prevents insert displacement during filling. Post-mould pull-out testing validates bond strength on every batch.
Applications
Our insert-moulded parts serve automotive (sensor housings, connector bodies), electronics (PCB mounting points, shielded enclosures), industrial equipment (load-bearing handles, adjustment knobs), and medical devices (reusable instrument handles).
Frequently Asked Questions
What insert materials can be overmoulded?
Brass, steel, stainless steel, aluminium, and copper are standard. We also process ceramic, glass, and electronic components (PCBs, connectors) with appropriate material selection.
How does insert moulding compare to post-mould assembly?
Insert moulding eliminates assembly labour, reduces part count, improves positional accuracy, and creates a hermetic seal between metal and plastic. Unit cost is typically 20-30% lower than separate moulding plus assembly.
Technical Specifications
Material: ABS / PC-ABS / PBT | Insert materials: brass, steel, aluminium | Positioning accuracy: ±0.05mm | Pull-out force: >500N | Press range: 80-250 tons | Cycle: 25-45s