WD Hearn recently commissioned and installed a Mitsubishi EA8S EDM Machine at Classic Closures, a Cape thin-wall container manufacturer.

Classic Closures, which originally traded as EMO Technik, operated one of the most capable toolrooms in the Western Cape and up till a few years ago was involved in the injection moulding of irrigation and other technical components; it also operated a ‘clean room’ scale plant at its premises in Epping, Cape Town. It was unexpectedly approached by a yoghurt manufacturer to produce a range of tubs and was at first reluctant to quote. At that stage the new client was a medium-tier supplier, but Classic was slightly apprehensive to commit to supplying into the food and beverage sector, which can entail taxing health standards and compliance audits by brand owners and retailers. “Eventually we decided to give it a go,” said Classic MD Martin Gassner. Now, just three years later, the relationship has gathered momentum and Classic has substantially expanded its thin wall container injection moulding plant. It is producing tubs and lids from 200ml up to five litres and builds most of the moulds on site. A far greater number of moulds is consequently being produced, plus the required multi-cavity moulds are also significantly more complex.

The EA8S EDM system involves a process in which thousands of electrical sparks are discharged onto the metal workpiece. Instead of cutting the material, EDM melts or vaporizes it, leaving little debris and providing a very accurate finish. The process is extremely accurate and can cut even finer detail than conventional spark erosion or CNC machining achieves. With multi-axis capability, the system can be programmed to operate automatically for days at a time, can change electrodes and workpieces automatically and is even capable of “conversational self-programming”. “The system is highly versatile, can cut hard metals and utilizes a relatively compact amount of workspace,” said Graeme Cooper of WH Hearn.

Classic personnel have also undergone training at the Mitsubishi plant in Germany, and Classic has even survived a number of retailer audits, having achieved Blue Status accreditation. Well done to Martin Gassner and the Classic Closures team.