PHOTO: High-precision metal cutting – Anyone unknowing would stroll by the compact Mitsubishi EDM system without so much as a glance, but Martin Gassner of Classic Closures, where the system was recently installed, and Graeme Cooper of WD Hearn Machine Tools, the supplier, know – and are very chuffed – about its capabilities

CLASSIC Closures, the Cape thin-wall packaging container manufacturer, has recently elevated the capabilities of its already highly competent toolroom with the installation of one of the most efficient specialised metal cutting systems available.

Classic Closures, which originally traded as EMO Technik, operates 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. The new client was a medium-tier supplier, at that stage, 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 from 200ml up to five litres as well as the lids can closures for these plus it builds most of the moulds on site. A far greater number of moulds is consequently being produced than before, plus the required multi-cavity moulds are also significantly more complex.

This resulted in a need for more efficient tool manufacturing equipment and Classic opted for an EDM (electrical discharge machining) centre from Mitsubishi of Japan. Essentially a CNC metal cutting system, the EDM system uses 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.

The EA8S unit, sourced from Mitsubishi’s plant in Germany, was supplied by WD Hearn Machine Tools, also of Cape Town.  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”. (It’s anyone’s guess who will be running Classic Closures by this time next year.)

“It is highly versatile, can cut hard metals and utilizes a relatively compact amount of workspace,” said Graeme Cooper of WD 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.