Overmolding Service
Get custom plastic parts molded with two materials or metal inserts.
Certifications ISO 9001:2015 | ISO 13485 | CTQ Inspections | ITAR
Our overmolding process produces custom prototypes and on-demand production parts in as fast as 15 days. We use aluminum molds that offer cost-efficient tooling, producing parts from a range of thermoplastic and liquid silicone rubber materials.
Overmolding is frequently used for:
- low-volume production parts
- bridge tooling
- pilot runs
- functional prototyping and testing
Overmolding Design Guidelines
Our basic guidelines for overmolding includes important design consideration to help improve part manufacturability, enhance cosmetic appearance, and reduce overall production time.
| US | Metric | ||
| Maximum Part Size | 18.9 in. x 29.6 in. x 8 in. | 480mm x 751.8mm x 203.2mm | |
| Volume | 59 cu. in. | 966,837 cu. mm | |
| Depth | 4 in. from parting line | 101mm from parting line | |
| up to 8 in. if the parting line can pass through middle of part | Up to 203.2mm if the parting line can pass through middle of part | ||
| Projected Mold Area | 175 sq in. (plastic) | 112,903 sq. mm (plastic) | |
| 48 sq. in. (silicone rubber) | 30,958 sq. mm (silicone rubber) |
Additional Notes
- Height may be limited if using a silicone as the overmold material, and deeper parts are limited to a smaller outline.
- Minimum part volume is 0.025 cu. in. (40.98 cu. mm).
- With substrate molds, we can maintain a machining tolerance of ±0.003 in. (0.08mm) with an included resin tolerance that can be greater but no less than 0.002 in./in. (0.002mm/mm).
- With thermoplastic overmolds, tolerances remain the same as substrate molds, however, if the overmold is LSR, then tolerances shift to 0.025 in./in. (0.025mm).
View our complete design guidelines
Overmolding Material Bonding
Chemical bonding between overmolded materials is possible, but material compatibility should be considered in order to achieve desired bond strength. Incorporation of an adequate mechanical bond is strongly recommended if bonding is critical to your application. An undercut is a good example of a mechanical bond.
| Substrate Material | ||||||
|---|---|---|---|---|---|---|
| Overmold Material | ABS | ABS/PC CYCOLOY C2950-111 | PC Lexan 940-701 |
PBT Valox 357-1001 |
PP Profax 6323 | |
| TPU - Texin 983-000000 |
C | C | C | C | M | |
| TPV - Santoprene 101-87 |
M | M | M | M | C | |
| TPE - Santoprene 101-64 |
M | M | M | M | C | |
| LSR - Elastosil 3003/30 A/B |
- | - | M | M | - | |
| TPC - Hytrel 3078 | C | C | C | C | M | |
| TPE-Versaflex OM 1060X-1 |
C | C | C | M | M | |
| TPE-Versaflex OM 6240-1 |
M | M | M | M | M | |
| TPE-Versaflex OM 6258-1 |
M | M | M | M | M | |
| TPE-Versaflex OM 1040X-1 |
C | C | C | M | M | |
M = mechanical bond (recommended)
C = chemical bond
What is Overmolding?
With overmolding, the production of the substrate parts is a standard injection molding process involving an aluminum mold with no heating or cooling lines running through it. Cycle times are a bit longer, which allows our molders to monitor fill pressure, cosmetic concerns, and the basic quality of the parts. When the total run of substrate parts are molded, overmold tooling is then assembled to the press. The substrate parts are placed by hand into mold where each part is overmolded with either a thermoplastic or liquid silicone rubber material.
Overmolding Resources
