Boehlerit Magazin 2016-EN

the past the quality of laser-cut inserts was on average 30% below that of inserts produced the conventional way, the two are now on an equal footing. Neither our customers nor we ourselves see any compromise in tool life”, says Gerhard Melcher. The only drawback carbide grades with a special microstructure in the surface (gradient carbides) have is that the laser removes the edge zone so that the higher fracture tough- ness of the gradient substrate in the edge zone no longer takes effect. According to André Feiel this is one of the few, but acceptable disad- vantages of laser-cutting. Boehlerit has written well over 1,200 laser programs since 2005. 60% for turning and 40% for milling inserts. “The situation has completely changed now. Today we are producing about 80% milling tools, primarily for toolmakers”, says Gerhard Melcher. One thing, however, still holds true: more than 90% of laser-cut inserts are ordered for development purposes. Only some 10% go direct to production. “It is mainly customised turning inserts that go into pro- duction – e.g. for the oil industry, for the production of sleeves or classic peeling inserts for which the bright steel industry may place orders of up to 150 units.” Gerhard Melcher thinks that the break-even point for laser-cut inserts is significantly lower. “If I was asked to make a rough guess, I would say that lot sizes of 50 pieces are more economical in laser-cutting. The influencing factors are the size of the insert and the volume to be removed that results when the negative of the chip former is programmed. On the other hand there are the costs and the time expenditure for press-ing tools and their optimisation.” There is no faster way to produce indexable inserts. Boehlerit laser-cuts complex milling or turning tool geometries in just a few hours: from the large peeling insert (left back) to the small, golden ½“ milling insert. Roughly calculated: 100 euros At the end of the day, the significantly shorter time-to-market is decisive, especially for toolmakers, says Melcher. The machining opera- tors, on the other hand, profit from the immediate readiness for use. “Laser-cutting is certainly a viable alternative for turning tools”, Melcher says, because far fewer inserts are needed thanks to the smooth cut, i.e. small lots are often sufficient for an entire order. “With milling inserts, it is mainly the cutting behaviour that is optimised. And with turning inserts, it’s the chip breaking behaviour”. This means that the develop- ment of turning inserts is significantly more complex, which makes la- ser-cut prototypes a much more attractive option according to Melcher. Expressed in money terms: “The ½“ insert costs roughly 100 euros, de- pending on geometry, edge preparation and coating. We recommend, however, that laser-cutting be followed by peripheral grinding to turn the minimal laser cut-off on the edges into a nice cutting edge with about one hundredth rounding.” Boehlerit usually responds to inquiries very quickly. This is due to the huge stock of blanks in Kapfenberg, Melcher says. “Blanks for turning inserts make the most sense. Currently we have some 200 types on stock”. If requested, Boehlerit laser-cuts all indexable inserts for face mills, high-feed milling cutters, radius and step mills. “There are hardly any limitations. But don’t forget that a laser-cut insert requires the suitable tool that will have a massive impact on the milling result.” Gerhard Melcher therefore recommends the full Boehlerit package consisting of indexable insert and tool holder. 011 BOEHLERIT MAGAZINE

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