The consignment manufacture of clip tooling (both hot and precision) for high volume production lines is a core business for Straight Line Engineering. All components of a clipping tool require a wire erosion operation to be performed to create the clip line.

Wire erosion uses the same principals to cut steel as solid-spark EDM, whereby an electrode is used to transfer a high voltage spark to the workpiece which in turn, removes material through melting. This method can machine extremely complex profiles very accurately (both 2D and 2.5D) from many types of steel. Hardness of the workpiece material does not affect cutting performance, which enables us to perform critical operations after Heat Treatment cutting out the need for roughing operations.

At present, SLE have 3 Fanuc robocut machines capable of machining through 250mm of steel. These machines have proved to be very reliable and have produced work of a very high quality even though they are used all day and every day’.

Solid-spark EDM is used as an alternative manufacturing method to HSM or

CNC machining. It is also used to good effect when the minimum internal radii of a tool impression is so small as to make direct machining by HSM an expensive option.

SLE use graphite as the electrode material for EDM machining. The inverse or negative impression is machined into a graphite block, which is in-turn burnt into the workpiece.

To produce graphite electrodes, SLE have invested in a Fanuc Robodrill. This machine was modified before delivery by replacing the coolant with a system that uses the die-electric found in the actual EDM machines, along with a media-less filter. The machine was then extensively sealed to ensure that any dust produced does not escape the machining area.

The benefits of this manufacturing process are two-fold, it enable rapid production of electrodes as well as infusing the graphite with die-electric increasing EDM performance