From a background in the 1990s when it was predominantly focused on copper components for the semi-conductor industry, Dawson Shanahan has developed an impressively wide customer base. Serving industries as varied as automotive, medical equipment, laser cutting and power switchgear, and producing volumes ranging from a couple of hundred a year up to two million a month in a wide variety of materials, the common thread is Dawson Shanahan’s innovative approach – and in particular the way it combines cold forming with machining.

The two Nakamura-Tome machines, for example, are used on a family of Copper components for power switchgear applications. Rather than machine these from bar or cylindrical billet the starting point is a cold formed blank.

As Dawson Shanahan’s joint managing director Les Reeves explains, “We look to see where our expertise will work best to give us a competitive edge and give the customer what they want. At the moment the cost of Copper is around £4,000 per tonne, and once you add on the mill’s conversion cost that can become £6,000. So the key is to use that material efficiently. By producing a cold formed blank we can achieve material savings of up to 70%. And by using a near net shape blank we can minimise the amount of machining required to finish it off. Significant cost reductions have also been achieved in both ferrous and non-ferrous materials using the cold-formed approach.”

When it came to deciding on new machines for the switchgear components, the crucial factor was reliability.

“We had previously had fairly modern machines from a different manufacturer, and while we were pleased with their capabilities, we were very disappointed by their reliability. They were fine when they were running, but you couldn’t rely on them to get the work out. So we decided to replace them earlier than we had planned. We looked at the market to see what would be more reliable and decided on the Nakamura WT100,” says Mr Reeves.

“We were very happy with the machine and its reliability, and impressed with the service and support we got from Turning Technologies. So much so that within a few months of getting the first one we ordered a second, and we fully expect to be buying a third this year. We have found the machines to be very competitively priced and everything that we hoped for.”

The WT100 machines have a maximum turning diameter of 190mm, bar capacity up to 42mm and a 165mm chucking capacity. The two servo-driven 24-station turrets deliver driven tooling power of up to 7.1kW and a Y-axis on the upper turret allows sophisticated machining operations. A further advantage is the machine’s small footprint.

“That was very important for us. We are always under pressure for space, so it is a real benefit to get a machine with this capability in such a small footprint.”

The two WT100 machines are used to manufacture around 15 different power switchgear components – around 90% of which are machined from pre-formed billets. Batch sizes are typically 1,000-off, with an annual requirement of around 100,000 components per year.

Balancing machining operations between the two spindles gives optimised production times, and the machines could produce the complete component in one hit. In this case however, Dawson Shanahan finds it more efficient to cut a series of angled slots on the end of the component as a second operation on a stand-alone mill.

“It is more efficient for us to do this in two operations rather than tying up the capacity of the Nakamuras. We can do the slotting offline while the Nakamura is doing the bulk of the machining work,” says Les Reeves. “We use the high-capacity, high-capability machine for what it does best.

“The machines do everything you would expect from this type of machine. But the main point is their reliability – which comes from the quality of components used, the design and they way they are built. These are very much production machines rather than jobbing machines. The parts we make on these two machines are selling