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hp tooling 2020 #3

  • Text
  • Components
  • Processes
  • Coating
  • Materials
  • Measuring
  • Milling
  • Grinding
  • Machining
  • High precision
The journal of hp tooling is an english, global publication on all aspects of high precision tools, accessories and their applications.

lead story Conceived

lead story Conceived from the process A development partnership between a machine manufacturer and a tool manufacturer The larger the series of parts to be produced, the more important are cycle times and tool costs. With large quantities, as for the car industry, the properties of both the machine tool and the tool itself need to be optimally suited to each other - and to the chosen manufacturing process. “We have a unique approach when we receive customer inquiries,” says Meinolf Wolke, Sales Team Leader at ELHA-MASCHINENBAU Liemke KG (ELHA) in Hövelhof. The medium-sized, owner-managed special machine construction company places the workpiece and its machining at the centre of development and devises an optimal solution perfectly designed for the process sequence. “In doing so, we take all the technical and economic requirements into account,” clarifies Wolke further. Only then do those responsible decide whether an existing machining concept can be used for the process or whether an individual, application-specific construction is required. Meinolf Wolke explains: “As well as providing the machine, we offer services that stretch from process development and the construction of fixtures all the way through to complete, ready-to-operate solutions with automation and production support.” Special tools for low total costs “The machining tasks are often as unique as the parts themselves - including in terms of the workpiece materials,” adds Alexander Wiesner, Technical Advisor at MAPAL. “Of course, a lot of machining work on com plex parts can be achieved with standard tools. But that often comes with significant draw backs in terms of cycle times, quality, and cost-effectiveness, particularly when large quantities are being produced.” In these cases, special tools that are precisely calibrated by MAPAL for the machining task in question are preferred. Carina Becker (left) and Jörg Rodehutskors (centre) with Alexander Wiesner in front of an FM3+Xhd production module “During the tool design phase, it’s essential to determine the necessary parameters for the machining process,” says Wiesner, “particularly in the case of challenging geometries.” In order to design the process in the best possible way, MAPAL often makes prototype tools. These are then used to carry out extensive tests with the part to be machined. “That, in turn, helps the equipment manufacturers design the machine with the values identified during testing,” continues Wiesner. He says that MAPAL has had a long-standing partnership with ELHA in this area. The following three examples demonstrate the resulting benefits to customers: A peek inside the interior of a production module reveals that it features two spindle row revolvers (left) as well as two quadruple spindle rows overhead Arrangement of four step drills on the right-hand side of the working area of a production module [photo provided by ELHA] Solid drills for the machining of suspension arms “We were dissatisfied with the solution that we had been using for drilling from solid in aluminium when machining a suspension arm, which included creating a fitting,” remembers ELHA Project Leader Friedhelm Dresmann. The company was then using tools with brazed PCD cutting edges. In order to keep the machining time as low as possible, these drills were being used with very high feed rates. The disadvantages of this solution were the high drive power required and the insufficient durability of the PCD cutting edges on the solid drill step. In search of a solution, those responsible at ELHA turned to MAPAL. Together, the employees of the machine manufacturer and the tool manufacturer worked to find a solution. What they came up with was a hybrid tool. The tip of the tool is equipped with three-bladed, CVD-diamond coated, ISO-indexable inserts for drilling from solid. The fitting is created using brazed PCD cutting edges on the second step of the tool. 6 no. 3, September 2020

lead story MAPAL’s research engineers tested the new tool in their own R&D centre. The results were impressive. In addition to the lower costs of the indexable inserts overall, the posi tive blade geometry meant that less drive power was required. The previous solution had often produced long metal chips - with the new tool, this was no longer an issue. The indexable inserts at the tip of the drill, which are under significant stress, can be quickly and easily flipped or replaced. As a result, the maintenance costs were also noticeably reduced. Altogether, the suspension arm manufacturers’ production costs for each drilled bore were reduced by over 50 %. Disc milling cutters for the machining of suspension arms “We also worked with MAPAL to find an efficient solution for machining forged suspension arms,” explains ELHA Project Leader Marcel Thieschneider. “Our goal was to develop process-reliable tools while maintaining the required cycle times.” For the suspension arm, a yoke needed to be created from the solid material at the end of the arm. During the required four-spindle machining process, the long-chipping workpiece material demands very high drive power to the machine. In addition to this, the internal contour of the part features a number of angles and radii, making the expulsion of chips during milling difficult. “In order to ensure short process times, we developed a disc milling cutter with ISO indexable inserts that enables roughing and finishing with minimum quantity lubrication in just one step,” recalls Alexander Wiesner. The indexable inserts are coated with CVD diamond. The precisely defined ar rangement of the indivi dual inserts limits the drive power required. After considering the comprehen sive tests at MAPAL and the data that resulted from them, ELHA set its machine to operate at this drive power. A positive side effect of using the disc milling cutter was the reduction in cycle time, as only one cut is needed. On top of that, Schematic representation of a production module [image provided by ELHA] Quadruple application of disc milling cutters on control arms [photo provided by ELHA] the tool only occupies one row of spindles, reducing the resulting tool costs for the end customer. Quadruple machining of fuel-supply distributor parts with deep hole drills [photo provided by ELHA] Deep hole drill for the machining of stainless steel forged components In order to optimise their processes, the customer asked ELHA to provide a solution in which the process described above, along with all other machining tasks, could be performed on a single production module using multiple spindles. The parts should leave the production module in ready-to-install condition. ELHA enlisted MAPAL to assist with the bore process previously discussed. The tool manufacturer was asked to provide a drill that was able to carry out the machining more quickly, with less deviation and less wear and tear. The MAPAL engineers developed a double-edged solid carbide drill designed to meet the requirements perfectly. With application parameters of Vc = 90 m/min and f = 0.5 mm, the new tool achieves a tool life of 80 meters - almost three times as long as the solution previously in use. Another special feature of the solution developed jointly by ELHA and MAPAL is that the workpieces in the clamping fixture rotate in the opposite direction to the drill during machining, which reduces the deviation of the bore even further. This leads to significant cycle time bene fits for the customer, who manufactures up to 5 million of these parts every year. And on top of that, they now only need one machine to carry out all machining tasks. Development partnership synergies “These three examples demonstrate the benefits of our close collaboration with MAPAL,” concludes Carina Becker from Technical Sales at ELHA. “And on top of that, the cooperation gives our design engineers additional freedom.” MAPAL’s specialists for the development of high-performance tools, as well as their exceptionally well-equipped R&D department in Aalen, make it possible to develop and intensively test new tool solutions even during the planning phase. That means ELHA is able to offer its customers even more well-engineered and economically advantageous solutions. ELHA-MASCHINENBAU Liemke KG is a family-run business that manufactures machine tools for cutting metal machining. The company was founded in 1930 and is known today for its machining centers, special-purpose machines and production modules. further information: www.mapal.com no. 3, September 2020 7

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