mold

Types of molds

A mold or mould is a hollowed-out block that is filled with a liquid or pliable material such as plastic, glass, metal, or ceramic raw material. The liquid hardens or sets inside the mold, adopting its shape. A mold is a counterpart to a cast. The very common bi-valve molding process uses two molds, one for each half of the object.

Articulated molds have multiple pieces that come together to form the complete mold, and then disassemble to release the finished casting; they are expensive, but necessary when the casting shape has complex overhangs.

Piece-molding uses a number of different molds, each creating a section of a complicated object. This is generally only used for larger and more valuable objects.

Blow molding is a manufacturing process for forming and joining hollow plastic or glass parts.

A manufacturer who makes molds is called a moldmaker. A release agent is typically used to make removal of the hardened/set substance from the mold more easily effected. Typical uses for molded plastics include molded furniture, molded household goods, molded cases, and structural materials.

Molding methods

There are several types of molding methods. These include:

Casting, the oldest term, covering a wide range of materials, especially metals

Blow molding

Powder metallurgy plus sintering

Compression molding

Extrusion molding

Injection molding

Laminating

Reaction injection molding

Matrix molding

Rotational molding (or Rotomolding)

Spin casting

Transfer molding

Dry Molded Fiber/Dry molding

Thermoforming

Twin sheet thermoforming

Vacuum forming, a simplified version of thermoforming

Fiberglass molding

Hand lay up moulding

Resin-transfer molding

Vacuum assisted resin transfer molding

Bladder moulding

Spray up molding

Reaction injection molding