Machine and tooling developed collaboratively

The larger the series of parts to be produced, the more important cycle times and tool costs are. With large quantities, such as those for the automotive industry, the machine tool and the tooling need to be optimally suited to each other, and the manufacturing process.

“We have a unique approach when we receive customer inquiries,” said Meinolf Wolke, sales team leader at ELHA-Maschinenbau Liemke KG (ELHA) in Hövelhof, Germany. The specialty equipment manufacturer places the workpiece and its machining at the center of development and devises an optimal solution. “In doing so, we take all the technical and economic requirements into account,” adds Wolke.

Developing specialty tools to fit unique applications is critical for producing high-quality parts and reduced costs and cycle times, said Alexander Wiesner, technical advisor at Mapal, a precision tool manufacturer. While machining complex parts can be achieved with standard tools, Wiesner said these tools can impact cycle times, quality, and cost-effectiveness, particularly when large quantities are being produced.

Challenging geometries may need custom tooling solutions developed beginning at the design phase where the necessary parameters for the machining process are determined, said Wiesner. Tool prototypes are often used to develop the production equipment.

This process was used during the redesign of solid drills for suspension arms, said ELHA Project Leader Friedhelm Dresmann. The company had been using tools with brazed PCD cutting edges to drill from solid in aluminum when machining the suspension arms. The process included creating a fitting. To keep machining times short, drills were used at high feed rates, but that required high drive power and limited the cutting edges’ durability.

ELHA and Mapal engineers developed a hybrid tool with a tool tip equipped with three-bladed, CVD-diamond coated, ISO-indexable inserts. The fitting is created using brazed PCD cutting edges on the second step of the tool.

The tool reduced costs, and the positive blade geometry meant that less drive power was required. It also reduced chip length, maintenance costs, and made for fast tool changes.

Another aspect of the project was developing disc milling cutters for the machining of the suspension arms. “Our goal was to develop process-reliable tools while maintaining the required cycle times,” said ELHA Project Leader Marcel Thieschneider.  

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 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.

The company developed a disc milling cutter with ISO indexable inserts that enables roughing and finishing with minimum quantity lubrication in just one step, said Wiesner. The indexable inserts are coated with CVD diamond.

The collaborative design process also worked to develop a deep hole drill for the machining of stainless-steel forged components. The customer manufactures high-pressure fuel-supply distributors for gas engines. “This requires drilling deep bores in narrow, forged, stainless steel blanks,” said ELHA Project Leader Jörg Rodehutskors. The material is difficult to machine, and the bore is 300 mm deep. The drill needs to experience as little axial deviation as possible, otherwise the part wall that experiences high pressure will fall below the required minimum thickness.

The customer wanted a process that could be performed on a single production module using multiple spindles, and the finished parts should be ready-to-install. Mapal developed a double-edged solid carbide drill with application parameters of Vc = 90 m/min and f = 0.5 mm that achieves a tool life of 80m. Another feature 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.

“These three examples demonstrate the benefits of our close collaboration with Mapal,” said Carina Becker, technical sales at ELHA. “And on top of that, the cooperation gives our design engineers additional freedom.”