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Wood Moulds/Patterns - They are generally used for low-production part runs or
initial design phase. They are relatively inexpensive and allow makes changes in
design very easily. On finalization of design and part specifications, the wood pattern
is then used to create a ceramic composite mould, or cast aluminium mould for
regular production.
Aluminium Moulds: They can be cast or machined. The advantages of aluminium
are its durability, good heat conductivity allowing faster cycle time and ease of
machining. Typically have temperature control lines with hot water or radiant heat
running through them to speed up production by regulating the heat of the plastic
being formed.
Cast AL moulds are casted in foundry. Alternatively, moulds are cut out of a solid
block of AL using a CNC machine and CAD program and are used for shallow draw
parts out of thin gauge material. Drawback with this type of mould is cost.
Steel Moulds: Durable moulds for most simple parts can be machined from
standard steel stock. Steel moulds are generally easy to plate but are usually
expensive to build.
Electroformed Moulds: These permanent metal moulds, are produced using
successive layers of copper, nickel, and chromium. The metal layers are formed into
a shell. These moulds can achieve precise mould details and produce parts with
excellent surface finish.
Plaster moulds: Inexpensive, easily shaped moulds can also be cast from
plaster. Plaster moulds are typically used for prototyping or on parts with small
runs. Poor durability, lack of heat conductivity, and the inability to control
temperature make them unsuitable for large production volumes.
Composite Moulds - Composite moulds are durable and temperature-resistant
moulds used for rapid forming cycles. They offer lower cost alternative to cast or
machined aluminum moulds. Composite moulds are typically made from filled
phenolic, polyester, polyurethane or epoxy resins, offers excellent dimensional
stability, good abrasion resistance and a smooth surface.
Important Considerations for Mould Construction
There are 2 basic types of moulds - Male & Female. Thermoforming process allows
control over only one surface of the part. Thus Positive (Male) or Negative (female)
mould type is selection depends on shape of the finished part, aesthetics and the
specific forming process used. Now if the part is drawn into the female mould, then
its exterior surface of final part will have the exact surface contour of the mould
cavity. The inside surface will be an approximation of the contour and will possess a
finish corresponding to that of the starting sheet. By Contrast if the sheet is draped
over a male mould, then its interior surface will be identical to that of the convex
mould; and its outside surface will follow approximately.

1 Full Thickness 1
2
3
2
4
3
Thin section
1. Initial contact point
4. Last Contact point Thin Section
Last Contact point
Male Mold Female Mold
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