Berker: Quality control for ideas

Berker: Quality control for ideas

What’s feasible and what isn’t? At the test laboratory of Berker, a manufacturer of high-grade electrical installation equipment, new ideas are constantly being tested.

But, if it’s all about quality metals, plastics and glass, what’s a cowhide doing here? Does this unusual material have anything to do with wire EDM? Andreas Krause, in charge of test lab CAD-CAM at Berker GmbH & Co. KG, Schalks­mühle, Germany, smiles. “Indirectly it does. The die for the punch press we’ve cut the cowhide on was produced on our FA20-S Advance from Mitsubishi Electric.” The outcome lying on the table is a cov­er strip for plug sockets. The product, which also has an interesting feel, is an exhibit specially designed for the next Berker fair stand.

A cowhide cover obviously isn’t one of the more usual jobs handled by the test lab. But isn’t anything here standard? Krause shakes his head. “We’re used to constant change combined with highly diversified and always new requirements. Because we test product ideas for their cost-effectiveness. The materials we process with wire EDM are mainly stainless steels, brass, copper and aluminium as well as specially alloyed steels. The machine’s task is to cut these materials with extreme precision, process security and economy.”

Four-axis geometries with precision contours

Precision to within three micrometres is called for when tool inserts consisting of a stamp and a die have to be eroded. Which is essential if the contacts and clamps that Berker punches and shapes with these tools have to fit snugly inside electric switches. In high-precision machining, we’re talking in some cases about parallelism and precision of within two micrometres. High surface quality is demanded as well. Frank Weitzel, responsible at the test lab for CNC wire erosion, shows us a tool insert. “Such four-axis geometries with pre­cision contours are a special challenge for wire EDM. So that we can leave noth­ing to chance and document our results, we control the quality of our work with a Zeiss microscope.”

“Our products have won several design awards and can be found in some of the world’s most exciting buildings.”

In view of these exacting demands, Ber­ker has made a versatile machine park available to its test lab, with the FA20-S Advance from Mitsubishi Electric being the only wire EDM ma­chine. When Krause talks about the ‘right’ process for a certain task, he often has the luxury of several options. “Some parts can be milled as well as eroded. The advantage of milling is its faster cutting rate, while greater precision and process reliability are achieved with EDM. What’s more, the set-up and programming effort at a wire EDM machine is much lower and it can run unmanned for 23 to 24 hours at a time.”

Concentrated expertise

The requirements come, for example, from Berker’s Plastics, Production or Rapid Prototyping departments, which then participate themselves in the pro­jects and supplement the five fixed members of the test lab with their own staff. There are plans for the test lab to be available for the entire Hager Group, Berker’s parent company.

Alongside the Hager brand, the group pools the expertise of other acknowledged specialists. One of them is Ber­ker, a pioneering manufacturer of high-grade, timelessly classical switches and intelligent building services. Krause pulls pictures of townscapes out of an envelope. “Our products have won sev­er­al design awards and can be found in some of the world’s most exciting buildings. It doesn’t surprise me, because we
use select materials for all of our products – glass, for example, instead of Plexi­glas, and solid metal instead of coated inexpensive materials.”

Noble and efficient

The premium manufacturer operates the test laboratory so that its products look noble, operate smoothly and can be produced efficiently – and because it wants to maintain control over its own expertise. The FA20-S Advance from Mitsubishi Electric has been part of the machine park since November 2011.
Its arrival coincided with the test lab’s re­location to more modern and brighter premises. Weitzel stands in front of the wire EDM system. “With the Mitsubishi advertising banner over the machine and the large carpet in front of it, the room has something of a place of worship.”

Berker purchased the FA20-S Advance, which is designed for maximum workpiece dimensions of 1050 x 800 x 295 millimetres, to replace a machine also made by Mitsubishi Electric and, at the age of 14 years, had reached the end of its useful life. The operator uses anoth­er system of the same make at another of its production locations. Weitzel points to the wire station of the FA20-S Advance. “Using conventional 0.25 millime­tre brass wire, our new machine cuts practically anything from the sim­­ple to the highly intricate and at a cost-ef­fective rate. By comparison, machines from other manufacturers achieve similar results only with coated wires that are about 30 per cent more expensive.” Another advantage of the FA20-S Advance
is that the new wire EDM machine has so far been running without a hitch. “The machine is in operation every day, and a breakdown would be a disaster,” Krause stresses. “This is why high availability was one of our prin­cipal demands, and Mitsubishi Electric’s global support was crucial for approval as a supplier to the Hager Group.”

Hager Group

The Hager Group in Blieskastel is a leading provider of solutions and services for electrical in­stal­lations in residential and com­mercial properties and for in­dus­trial applications. The glob­ally active family company has a roughly 11,200-strong work­force and generates annual sales of almost EUR 1.5 billion. The group’s products and ser­vices extend from building installation and consumer units, cable ducts and house elec­tronics to bus systems.

“Another advantage of the FA20-S Advance is that the new wire EDM machine has so far been running without a hitch.”

The user-friendly auto-threading system of the FA20-S Advance represents a quantum leap in wire EDM development. Weitzel shows us how it works. “Compared to the old system, the new one takes only ten seconds to thread the wire, which makes it 90 per cent faster. This saves us a lot of time – as does the flushing tank that can now be filled swiftly with dielectric fluid. In addition, the new threading system requires less maintenance and, like the FA20-S Advance as a whole, is dead easy to operate. Krause demonstrates the easy access to the control and maintenance elements. “We commissioned the machine after a one-day introduction. A course of instruction was only necessary for maintenance.”

Breaking new bounds

By investing in the FA20-S Advance wire-cutting machine from Mitsubishi Electric, Berker has added to the ef­fi­ciency of its test laboratory. Which means that, in terms of the machining of new electrical installation components, new bounds have been broken.

 

Interview