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Multi-material/Multi-color Mold
What Drives OEMs to Multi-Material
Molding?
Benefits of Multi-Material Molding
Supplier Involvement
Part Design Considerations
System Compatibility Issues
Material Considerations
Molding Machine Manufacturer Involvement
In-Mold Assembly
Over Molding
The Over Molding Process
What Drives OEMs to Multi-Material Molding?
- Eliminate part assemblies
- Increased product appeal
- Increased product functionality
Benefits of Multi-Material Molding
- Elimination of Secondary Operations
- Decorating/Aesthetics
- Tactile Surfaces
- Sealing Systems
Supplier Involvement
All parties to be involved at the beginning of every multi-material program:
- Customer/Product Designer
- Moldmaker
- Molder
- Material(s) Supplier
- Molding Machine Manufacturer
- Robotics Supplier
Part Design Considerations
- Optimize wall thicknesses
- Location of sequential material
- one side of parting line
- across parting line
- multiple locations on substrate
- single or multiple gate locations
- Shut-offs for sequential materials
- Trapping substrate to prevent movement in new cavity
System Compatibility Issues
- Individual Shot Sizes
- Material residence time in barrel and hot runner system
- Molding Machines
- Barrel configurations
- Tooling Technology
- Complex tools
- Materials
- Attacking resins
- Non-bonding resins
- Different shrinkage rates
Material Considerations
- Will bonding occur?
- Will mechanical interlocks between molded materials be required?
- Can materials be processed at similar mold temperatures?
- Material sequencing: which material first?
- Melt temperatures
- Material compressibility
- Shrinkage variable for next shot
Molding Machine Manufacturer Involvement
- Specifying a molding machine to match the mold
- Higher degree of process control required
- Rugged machine platens
- Sizing barrel and shot sizes to meet the needs of the mold and molded part(s)
- Numerous barrel configurations available
In-Mold Assembly
- Molding two or more materials which do not bond due to incompatibility of materials
- Enables parts to move freely over one another
Over Molding
- Sealing Systems
- Molding gaskets onto a sealing surface
- Cosmetic & Aesthetic
- Decorative color molded parts, provides product differentiation
- Tactile Surfaces
- Gripping surfaces
The Over Molding Process
- Inject the first/base material
- Mold open with repositioning of the base material to the sequential shot location
- Mold close
- Inject the first & second materials through independent barrels
- Mold open and part ejection
- Mold relocation to first material location
