Author: Miralde Kotze

The Product Development Technology Station (PDTS) assisted a client from Durban cutting paper cores into different lengths. The station built a machine, called the Core Cutter, which solved the problem and addressed specific needs.

The idea was to eliminate manpower and also improve the efficiency of the cutting process. Therefore an adjustable machine was needed and it should be able to change according to different lengths.

An existing cutting machine was used by the client, but he couldn’t cut different sizes of core. A new machine was conceptualized after research was done on the existing product.

The biggest challenge involved programming of the machine as different lengths and diameters needed to be cut. Research was also done by the PDTS on the type of blades used to give a clean cut on the cores.

Programming and manufacturing happened in conjunction with each other. The last step was testing the Core Cutter to see if it fits the client’s needs, which were mainly to improve the productivity and variability of the cuts.

A vegetable farmer in the Free State requested the Product Development Technology Station (PDTS) to design and manufacture a machine that will sort various sizes of tomatoes. This is needed to grade tomatoes for classification purposes.

This process was previously done by hand and the client, who farms near Petrusburg, wanted to speed up the sorting process and increase production capabilities.

In order to address these needs the PDTS created a concept and took inspiration from a sorting machine viewed in Bethulie. This included a sorting process that starts with a chute or conveyer channel where the tomatoes are deposited onto brush rollers that clean them, during which overhead nozzles spray a disinfectant onto it.

The tomatoes then move to foam rollers that dry them. Then they go onto a conveyor that moves them onto a rotating cone that enables the tomatoes to fall through different sized slots.

Finally, the produce is deposited into three different conveyer channels according to size. From here workers can pack them accordingly and they are graded in three sizes: small, medium and large.

The Tomato Sorter therefore allows production to increase as workers who used to sort tomatoes are now free to harvest vegetables and do other work. This in turn creates the opportunity for more work to be done.

The Product Development Technology Station (PDTS) developed a 3D printing process that prints from conventional injection mould pellets, rather than expensive 3D printer filament. Therefore a much wider selection of cost effective plastics are available to use in 3D printing. By shredding recycled plastic, pellets can also be produced. It is also roughly ten times cheaper than conventional 3D printing methods.

The PDTS pushed boundaries by building a large 3D printer, 1.5 m x 1.5 m 1.5 m print volume, with which larger volumes can be 3D printed as existing printers usually are quite small and expensive.

By developing this printing process to operate on recycled material, it also is a sustainable green solution to manufacturing needed devices, spare parts and prototypes. This system can operate locally on recycled plastic from the surrounding areas to improve the accessibility and availability of much needed replacement parts, prototypes and functional goods.

It is a combination of the station’s strong mechanical and electronic capabilities working in collaboration to produce this unique process. The PDTS’s advanced manufacturing effectively produce the complex mechanical parts needed to consistently extrude pellets. The electronic requirements and firmware needed are also attended to by the station to control the new 3D printer.