One EDM machine builder satisfies mould maker’s wide-ranging needs

Die-sinking systems from ONA serve for modification and repair of very large moulds and for fine-sparking of high-precision small moulds.

The first CNC machine tool UK mould maker C&M Mould Tools acquired was a die-sinking EDM machine from ONA Electro-Erosion S.A. As the company expanded through the 1990s, it came to operate two ONA CNC die-sinkers and some other CNC machine tools. More and more space and machinery became necessary as C&M started to focus on mould tool modification and repair of large tools for, primarily, German and Chinese mould makers supplying the automotive industry. Then, recently, it began to undertake jobs at the small end of the product spectrum, and for this the company acquired from UK agent Warwick Machine Tools an NX3 die-sinking EDM by ONA, still its machine builder of first resort.

Modification and repair

Company director Nick Moth says C&M’s tool modification service is a matter of providing local support for customers. His company uses customer-supplied CAD data to alter tools to the correct standard. Many projects involve large mould tools, for which a purpose-built factory area with suitable cranes was constructed.

Moth cites its design as one significant advantage of an ONA EDM machine. Because its head moves, rather than the table, large moulds such as those for automotive grilles and bumpers, which exceed the capacity of the tank, can be supported outside of the tank, and the machine operator can work just on the area of the tool that needs repair or modification. The mould tool is static, so its weight does not affect the machine’s dynamic performance or positional accuracy. Also, one of the ONA machines, modified to C&M’s specification, has an additional 200 mm in the z-axis, allowing deep tools to be machined.

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Having dedicated resources to do this kind of work, says Moth, means that performing urgent repair work on moulds for other customers does not delay progress on tool modification projects. Some 30% of the company’s turnover comes from this side of the business, an area that produces good profit margins because such minimal material outlay is required.