Tooling Tooling solutions for complicated parts
When HaGeForm Sachsen GmbH was in despair about a cylindrical pocket, the visit from Mapal came just in time - and the right tools were also on board.
Around 90 percent of HaGeForm Sachsen's customers are located within a radius of 50 kilometres. The proximity is a great advantage for the manufacturer, because fast delivery times are becoming increasingly important. "We do a lot of things on demand," explains Sebastian Baier, who took over the company together with his father in 2012. "We usually bring the components to the customer by car, there are no long haulage routes." In addition to components for tool and mould making, Stollberg also produces components for general mechanical engineering and a wide range of other industries.
From toothbrushes to Formula 1
The region's automotive suppliers make up a large part of the broad spectrum of customers. The parts produced by HaGeForm are mostly used in the forming, cutting or spray coating of sheet metal. It is often a question of one-off productions, sample parts, prototypes and small series. The orders range from moulds for toothbrushes to parts for Formula 1 racing. Even when the scientists at the Technology Campus of Chemnitz University of Technology come up with "crazy new things", as Baier says, the manufacturing know-how of his company is in demand. The required tolerances are usually in the hundredths range, but accuracies of 5 micrometres are also feasible in Stollberg.
In addition to four wire-cut EDM machines, two die-sinking EDM machines and a grinding machine, three milling centres with three, four and five axes are available. Components that are to be machined by both milling and EDM are shifted to the respective areas depending on the workload. In order to reduce process times, the company strives to mill as much as possible, because die-sinking EDM takes much longer and is therefore correspondingly more expensive. Milling currently accounts for almost half of the orders, and the trend is rising. Parts that until recently had to be eroded can now also be milled. The partnership with Mapal has also contributed to this.
When Felix Wendler, product specialist at Mapal, came to Stollberg just over two years ago, he had a mission: to test new tools for tool and mould making, which had been trialled in the Mapal test centre, on real components at users' premises under realistic conditions.
Cylindrical bag challenge
During Wendler's visit, HaGeForm had just had a tough nut to crack in the hard machining of mould inserts made of powder-metallurgical steel with 65 HRC. Maik Seibt, head of the milling department at HaGeForm Sachsen, describes the situation: “We couldn't get certain inserts for a component to be cylindrical. The pocket for the insert was always too big at the top and too narrow at the bottom, it just wouldn't fit.” Without further ado, the prototype brought along by Wendler was tested and the result was convincing right away. The machining succeeded exactly cylindrically and to the µ. "That was already at the limit of our IR measuring device," confirms Seibt. Mapal has now incorporated this tool into its standard range in various versions as the Optimill-3D-CR-Hardened corner radius milling cutter.
Milling instead of grinding
The Mapal technician was also able to help when there was a bottleneck on the grinding machine. Milling instead of grinding was the motto. Wendler demonstrated that it is possible to mill down several millimetres from a large plate with a hardness of 62 HRC within a very short time in order to re-set the broken-out ring tooth. Finally, HaGeForm set out to replace EDM with milling for certain workpieces. Previously, the parts had been clamped in the afternoon and then vertically eroded until the morning. What used to take a night is now done in two hours.
The customer gains flexibility here because for more parts he has the choice between die-sinking EDM and milling. If orders are to be processed as quickly as possible, milling is the better choice.
For some parts, the transition to complete machining was successful. For example, a fine blanking die made of powder metallurgy metal was removed from the machine after milling in order to subsequently vertically erode small corner radii with shoulders.
We couldn't imagine that it could be done any other way. Now we can cover all that with milling machines, which is quite an innovation.
By now, the Optimill-3D-HF-Hardened high feed cutter and the Optimill-3D-BN-Hardened ball cutter are also regularly used for hard machining at HaGeForm. The Optimill-Tro-Hardened trochoidal milling cutter is used for two-dimensional roughing directly in the hard material. The full utilisation of the cutting edge length, which always corresponds to 3xD with this tool, is thus possible without any problems when machining material hardnesses of up to 65 HRC and guarantees maximum economic efficiency through the highest stock removal rates in the shortest possible time.
Mapal has come to be appreciated as a problem solver. For very complex titanium parts, a possible machining strategy was mulled over for a long time, and then finally the technician was called. Felix Wendler came with the right milling cutters for titanium and also stayed until a suitable programme for the complicated part was created in Stollberg and the machining was up and running. Complex shapes in combination with special materials always place new demands on the pavers. “We receive very good support from Mapal,” praises Maik Seibt. “When we have problems, a phone call is often enough. It's good to have a competent contact person you can ask.”