Custom and bespoke fasteners for use within a moulded assembly
Overview: a customer who had previously been using three standard bonding fasteners to form a mounting point within a catamaran hull (1) requested a bespoke version which combined the existing threaded inserts with one large base plate, thereby improving the integrity of the mount point and simplifying the moulding process.
The mounting point had to be capable of withstanding significant tensile and shear forces, so the three 23mm round base plates were changed to a larger 100 x 50mm replacement. The additional incorporation of evenly-spaced perforations reduced the weight of the part and allowed moulding material to bind within the assembly, thereby fixing it securely in place within the material wall .
Moulding: the mould includes two mounting points for the fastener assemblies. One of these is shown at (2) with one of three fixing bolts protruding.
The fasteners are attached to the mounts using three bolts, each picking up on a threaded insert in the fastener assembly (3). A gap of approximately 10mm remains between the mould and base plate, with this area and a similar depth behind the base to be filled with high density Polyethelene, encapsulating the assembly and leaving a firm but discreet mount point on the finished hull (4).
This mounting point is one of four used on the catamaran for securing cables (shroulds) from the top of the mast to each of the two hull assemblies. With the fastener being manufactured from marine-grade 316 Stainless Steel and produced to a high specification, it will easily last the lifetime of the catamaran.
Please note, this application is not specific to the marine industry or to rotational moulding procedures. Whether the fastener assembly is surface mounted or incorporated within an injection, vacuum, rotational or hand-layup moulding, a similar or modified version can easily be designed to suit your requirements.