What is Co-Injection Molding
Co-injection molding(or sandwich molding) a process that creates a skin and core material arrangement in a molded part. The skin material is injected first into the mold cavity, and is immediately followed by a core material. As the skin material flows into the cavity, the material next to the cavity walls freezes and material flows down a center channel. When the core material enters it displaces the skin material in the center of the channel by pushing the skin ahead. As it flows ahead it continues to freeze on the walls producing the skin layer
Machine Based Co-Injection molding
The Co-Injection process requires two injection/processing units. The units generally inject material through a manifold located at the end of the injection barrels. The manifold ports the two melt streams into a centrally located nozzle. The machine controls the injection units to achieve a skin-core-skin flow sequence through the manifold into the mold. Last skin flow is needed to clear the short nozzle section of core material and to seal the gate area with skin. This arrangement can be used on any single or multiple cavity, conventional cold runner mold.
Mold Based Co-Injection
This same process can be achieved on a hot runner mold by utilizing a hot runner system from hot runner Corporation. This system, sometimes identified as “Mold Based Co-Injection”, still utilizes two injection units. The two melt streams are directed into the mod via separate channels. These two channels remain separate until they reach the gate area of the part. At this point they flow through a nozzle arrangement similar to the normal co-injection manifold.
Co-Injection Benefits
- Lower Cost Parts
- Higher Strength Core
- Sound Absorption Core
- Reduced Cooling Time for Lower Temperature Core
- Improved Aesthetic Qualities
- Combined Property Characteristics
Advantages
- Foamed Core for reduced weight and noise transmission
- Glass filled cores for improved physical properties
- Low cost core for cost savings.
- High gloss skin material over structural core material for combination of aesthetic and structural properties.
- Post Consumer Recycled material in core. Environmental friendly.
- Post Industrial recycled Material in core
- Reground painted parts recycled into core.
Sincere Tech is one of the best top 10 plastic injection mold manufacturers in China, offering custom plastic mold, die casting tooling, injection molding, CNC machining, post-manufacturing, surface finish, assembly, and delivery, our molds and products are shipped to worldwide, we offer all in one stop service from part design to manufacturing, we can save 40% of your injection mold cost and die casting tooling cost, if you have any project that need mold, die castings, machining, part design service, welcome to contact us.