Multotec toolroom
The tools required are mainly for rubber and polyurethane injection moulding, rubber compression moulding and cast polyurethane products.

Continued growth in demand for Multotec Manufacturing’s screen panels has led the company to expand and upgrade the dedicated toolroom at its extensive manufacturing facilities in South Africa.

According to Ian Chapman, engineering manager at Multotec Manufacturing, these technology investments have accelerated the tool manufacturing process and delivered better tool finishes. This translates into enhanced product quality, greater speed to market and more cost effectiveness for the end-customer.

The tools required are mainly for rubber and polyurethane injection moulding, rubber compression moulding and cast polyurethane products. The wide variety of tooling produced includes ‘mother moulds’ and components such as frame bars, cores and inserts.

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“By 2015, our success in growing markets had placed considerable demand on our toolroom,” Chapman says. “This led to the replacement of two CNC milling machines and adding two new wire electric discharge machines (EDMs) in recent years.”

The new milling machines use specialised Heidenhain controllers, which strengthen Multotec’s jobbing capability for customised tooling. Based on the specification from the sales team, drawings are created for the company’s tool and dye makers. They, in turn, convert these drawings using computer-aided manufacturing (CAM) software to create the tool-path for the CNC machine.

“Our experts’ familiarity with the Heidenhain language speeds up our work and avoids human error,” he notes.

Wire EDM machines are another key resource in the toolroom, using electrical erosion technology to cut relatively long tool-pieces accurately and finely.

“Unlike a milling machine – where there is contact between a tool and a work-piece – on the EDM there is no engagement with the wire and hence no forces to accommodate and few residual stresses,” Chapman says. “This allows us to cut pre-hardened steel without distorting its shape, creating very fine tolerances in our finished tooling.”

To augment the existing two EDMs, a third was acquired in 2018, with even larger wire spools than the previous models. This allows longer production runs of up to 90 hours, improving cutting strategies and productivity. So successful was this investment that a fourth wire EDM was purchased and installed in 2019.