Plugs and Moulds


The plug is the basis for shaping the moulds and tools. It requires a smooth, non-absorbent, non-deformable, solvent-resistant surface, as well as increasingly smaller dimensions in the direction of release. In compliance with the client’s quality requirements, all types of plugs are fabricated manually as well as with a CNC milling machine – e.g. a wooden shape of built-up frame design, or a Styrofoam core with a CNC-machined fibreglass coating. If desired, Fassmer will draw up a comprehensive measuring report and a 3D scan for all plug types.

Thanks to many years of experience and the use of the latest materials and technologies, Fassmer’s plugs are extremely durable. Their substructure is made of aluminium, steel or plastic, providing them with the necessary rigidity, and they are individually constructed according to the client’s data. A sandwich layer of epoxy laminate and a core material gives the plugs their desired shape. They are then covered in epoxy paste and milled until they have their exact final shape. Depending on geometry and surface finish, between five and ten demoulding processes are possible. Plugs must be highly vacuum-tight, because many moulds are made for the vacuum infusion method. The tightness is therefore checked and confirmed by Fassmer Quality Control.


Fabrication of a GRP mould is usually preceded by the plugs. Fassmer predominantly fabricates moulds and manufacturing tools from fibre composites. Their in-house plug and tool mould making departments and the use of state-of-the-art technology mean that Fassmer can address customer requirements and develop individual solutions fast and flexibly. Only the right manufacturing method leads to the best results. As a competent partner, Fassmer is in close contact with the customer, from the development and planning stages right up to the actual production process. Fassmer’s plugs and moulds are remarkable for their high dimensional accuracy, rigidity, and durability. Plugs and moulds are supplied by a single source. Only high-quality and low-shrinkage materials are used, such as isophthalic acid resins, vinyl ester resins, or epoxy resins.