The actual plastic component originates from the working mould. Whoever possesses and looks after the working mould can manufacture identical plastic parts over and over again years into the future. To do this, design engineers are no longer necessary, all planning is completed and all the knowledge is contained within these mouldings. By contrast, subsequent series manufacturing is often routine.
One of the biggest challenges with large components is in keeping the shrinkage processes of the material under control. Every manufacturer has their own experience in this regard and employs various materials to this end. After all, if a mould shrinks uncontrollably or warps in the manufacturing process, the resulting series parts will not fit together neatly.
Depending on customer requirements and tolerance specifications, various working moulds are used at JAKSCHE. Standard GRP working moulds have lower requirements in terms of shrinkage and acceptable tolerances. With carbon-glass-epoxy matrix moulds, less shrinkage and low tolerances can be achieved.
Producing plastic moulds
There is no universal process for producing a plastic mould. Broadly speaking, the production of a working mould is defined by the following steps:
Several layers of glass roving are laminated onto the core or master form with a special mould making resin, which shrinks less. Large components are braced with reinforcing materials, such as balsa or sandwich panels. The structure of the moulds usually consists of a supporting structure made of steel or wood, onto which the forming shells are fixed.
A steel frame prevents the mould from warping. After curing, the mould is separated from the core. The moulds have smooth surfaces and are sealed with wax systems or releasing lacquers. The finished mould is coated with release agent and then covered with a gelcoat. Then the manufacture of the actual plastic component begins.