Momexx show how and why they are Mould Making Experts in their field in a case study for a new type of shoesorter, produced for van Riet Material Handling Systems. The company required that the sorter be part of a grader which amongst other uses could be used for sorting packages.

The main purpose of the sorting shoe was to efficiently process packages, first introducing them and then pooling and identifying them. The shoe would then "push" the packet to the correct sorting destination. The sorting shoe would be the second generation version.

Problem statement
Van Riet provided Momexx with 2D drawings identifying the requirements of the product. Momexx then investigated the feasability of the product and the required construction. A complex product, the shoe must be able to "push" packets of various sizes, weights and shapes in the right direction. Because of the nature of the shoe's requirements, the strength of the sorting shoe was one of the most important conditions to consider.

During the first phase of the trials, FEM analysis showed that the shoe was not achieving the desired strength. Furthermore, the steel frame plate shifted during the test spray.

As mould making experts, the Momexx team were able to optimize the propositions in order to achieve the required result leading to the final production of the moulds.

Moulds and craftsmanship
Momex produced a total of three single cavity moulds for the shoesorter, manufactured in Momexx's factory located in China. The resulting moulds were partly made of hardened steel.

End result
The resulting sorting shoe was made with a c-shaped steel frame plate which gives the advantage of a compact sorter process. The sorting shoe itself comprised several parts:

• A 2K product and a product around the steel plate which was "sprayed" and achieved through the use of overmoulding.
• The hard plastic body of the 2K product in PA6 was produced by a single cavity mould and the part manually placed inside another mould. It was then moulded in part by soft TPE - a rubbery material that reduces the peak of kinetic energy when the package is pushed away.
• The steel frame plate part of the product (a die cutter part) was held in place by pins and a magnet and sprayed with a PA6 product.

The sorting shoe is now in wide use across various packet services.