Supplier on equal terms.
Precision, flexibility and speed – this is what is demanded by the customers of TECHTORY when it comes to the production of automation solutions. It was therefore only logical that these were the attributes demanded by TECHTORY when choosing its wire EDM machines.
TECHTORY, a company in the Baden region of Germany, puts things to the test. To be more precise, the company produces, among other things, test rigs for the leak testing of motor vehicle exhaust systems and for the endurance testing of vehicle components and individual end-of-line test benches for a wide range of production processes, e.g. the production of sanitary fittings or in medical technology. TECHTORY also specialises in the development and production of automatic assembly machines, robotic gripping systems, fixtures and the automation of machine tools. On top of all this, TECHTORY additionally produces CNC milled and turned parts under subcontract, from single parts through to whole series. Its attention to detail and the associated delicate touch are what led the company in Appenweier to its most recently added activity – that of subcontracted wire EDM. In doing so it applies very high standards of its own, as Bernd Himmelsbach, Wire EDM Project Manager at TECHTORY, reports: "With our own products we have an extremely high manufacturing depth, so we gained experience of the various production methods early on and know what to expect of the various production machines." The location in Appenweier thus accommodates CNC turning and milling centres of the latest generation. At the end of 2011, the company decided to add a wire-cut EDM machine from Mitsubishi Electric to its machine park. Until that time, it obtained wire-cut parts from outside sources. "The limited flexibility with farmed-out parts prompted us to consider building up wire EDM as a new business activity," says Himmelsbach outlining the beginnings. "We also wanted to expand our mouldmaking activities, although we quickly made a name for ourselves as wire EDM subcontractors."
Meanwhile, TECHTORY uses 80 per cent of its wire EDM capacity for machining parts under subcontract for a variety of markets. "We're going a bit against the trend – we largely serve the immediate region and have close ties with very many companies in the area," says Himmelsbach. This may sound humble, but the list of references shows that these are almost exclusively so-called "hidden champions", i.e. small and medium-size businesses that have established reputations for themselves on the world market. "Our customers want to do business with firms on equal terms who know what they're talking about. The high level of skills of our staff that know the machine tools like the backs of their hands is therefore our biggest asset," says Himmelsbach pointing out a keystone of the firm's success.
Overall, wire cutting has expanded strongly in the last three to four years. "Although milling is faster and of course less expensive, there's no alternative to wire erosion when it comes to tapers, small radii, complex contours and surface finishes of less than 3 µm," says Himmelsbach explaining the upsurge with this form of machining. TECHTORY's expectations of EDM machines were clearly defined from the outset: high accuracy of ±3 µm, trouble-free operation during unmanned shifts – and ultimately the machine should operate cost-effectively.
When deciding in favour of the machine from Mitsubishi Electric, the company didn't take the easy option by any means. "We compared a lot of machines. In the end, it was the price/performance ratio at Mitsubishi Electric that tipped the balance for us. And we also found the advice given during the quotation phase helpful," says Himmelsbach enumerating the most important reasons. In addition, there were pre-programmed modules for subcontracted jobs that made getting started easier. As a jobshop, it is also important to be able to provide the service inexpensively, so it's essential to have a machine that runs economically. Machining speed – for jobshops every minute counts – is the decisive parameter for a cost-effective price per part and hence for competitiveness.
The FA20-S Advance V was initially chosen. Only a year and three quarters later, they decided to purchase a second, smaller machine, the MV1200S. "We had, and still have, a lot of jobs involving the machining of smaller workpieces," Himmelsbach explains. The machines therefore complement each other excellently and TECHTORY can respond flexibly to inquiries. While dies tend to be produced on the large machine, the smaller one mainly handles punches. Both machines are used almost continuously in two shifts per day, and many jobs run overnight. "Our customers appreciate our ability to react quickly and flexibly," says Himmelsbach describing the daily work. The standard automatic wire threader has proven itself in everyday operations. Another tip from Himmelsbach: "It's best to use the wire from Mitsubishi Electric as it is perfectly adapted to the machine and runs more smoothly. And it lasts longer. Nothing else is really up to scratch," he frankly admits. "Cheaper isn't always better." Today, long machining times with short periods of downtime are possible, even during unmanned operation.
The team is also grateful that, in the event of any failures – such as wire breakage or flaws on the surface of the material – the machine automatically sends a specified error text message to the responsible employee. This was particularly useful during the familiarisation phase, but such occurrences have now become rare. "Mitsubishi Electric's introduction to the machine is really good because you're taught on your own machine with your own workpieces," Himmelsbach explains. Incidentally, support continued after commissioning as well, he adds. "If we have any queries, we always get immediate answers, and we appreciate the exchange from expert to expert." In practice, the machine's good accessibility for loading and unloading workpieces and finished parts has proven beneficial. What's more, the contours of the parts and the planned cuts can be graphically displayed at the machine. The two wire EDM machines run smoothly and are well looked-after by staff. "We want the machines to run for a long time to come, so we keep strictly to the given maintenance plan." They have also been pleasantly surprised by the machine's energy consumption.
Constant quality checks
"Wire EDM has meanwhile become a mainstay at TECHTORY and one that we also of course use in our own production activities," says Himmelsbach. In practice, it has turned out that the surface finish with roughness below 0.5 µm declines strongly on competition machines without air conditioning. Although the team has no reservations about the quality of Mitsubishi Electric wire-cutting machines, the company invested in measuring equipment last year. Especially for customers in the automotive industry and its suppliers, an air-conditioned precision measurement room was commissioned where each workpiece is checked in detail and where the results are documented. The dimensional accuracy of the produced parts is monitored with high-grade measuring instruments that are in turn subject to constant control. All measuring machines are calibrated at regular intervals so that reproducible results are maintained.
Extensions are standard
"We want to constantly improve our production," explains Himmelsbach. In only 2012, production and warehouse space was extended by 900 m² and, last year, office space was also upped. Himmelsbach is therefore convinced that this trend will continue. "Wire EDM experts are thin on the ground. Thanks to Mitsubishi Electric's training, the first steps are easy, and the longer you work at the machine, the more expertise you acquire and the higher the standards expected by the customer." TECHTORY's EDM team has no qualms about tackling even more complex and difficult machining jobs in order to gain a foothold on further markets."
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