Closed Molding is a process that is useful for parts with complex geometries, strict cosmetic requirements, tight outside tolerances, or a combination of all three. However, parts that are too complex for this method must be separated into multiple tools to be later bonded together.
- Unique Custom Internal Geometry
- High Flexibility
- Allows Molding Parts with a Negative Draft
Limited Material Selection
Variations of Closed Molding
- Bladder Molding
- Compression Molding
- Press Molding
- Modified Closed Mold
How Does Closed Molding Work?
We use sheets of pre-impregnated fibers called “pre-preg.”
- The sheets are wrapped around an inflatable bladder and then placed inside a mold cavity
- Once the mold is closed, pressure is applied to the inside of the bladder causing the bladder to expand pushing the pre-preg outward against the inside of the mold cavity
- Heat is then applied to the mold to solidify or “cure” the composite in the shape of the inside of the mold cavity
- After curing, the solid composite form is extracted from the mandrel or tool. In the case of a tank or other closed end vessel, the mandrel could be left inside the composite form or dissolved out via various methods.
Exceptions for Variations
Modified Closed Mold
- 5 press molding????
- pressure ranges from x to x
- Sizes from ____ to ____