Precision Machining Ensures Precision Fineblanking

The exacting nature of fineblanking demands precision tooling. To ensure that its tooling makes the grade, Feintool has invested heavily in vertical machining centers.

“Faster, better, lower cost—pick two.” It’s a pervasive phrase expressed across a range of industries and markets, but is it true? According to Christoph Trachsler, CEO of Feintool North America, customers don’t have to make that choice when it comes to Feintool’s fineblanked parts services.

“What matters most at Feintool is reliably delivering precision parts at a competitive cost for our customers,” says Trachsler. “Our customers don’t have to choose between quality, delivery and cost. We are continuously improving processes, from component and tool design, to system engineering and large-scale component production, to deliver greater results across all criteria. It’s how we stay competitive and help our customers succeed.”

With more than 60 years under its belt, Feintool develops fineblanking systems and produces prefinished fineblanked and formed components, and provides technical expertise to support customers with research and development and prototyping. It operates out of facilities in Europe, Japan, China and the United States, with its North American headquarters located in Cincinnati, OH.

The company’s fineblanked parts services provide a cost-effective means for companies to acquire high volumes of extremely precise stamped parts, making Feintool a premium parts supplier to the global automotive and medical industries.

Delivering a high level of repeatable precision is no easy feat, though. Due to the intense pressure of the fineblanking process, tooling used within the presses typically are composed of 64-HRc hardened steel. And according to Beat Andres, Feintool’s operations manager of toolroom and production tooling, identifying a “capable machine for this type of hardmilling” is difficult.

“Many of the tools that we manufacture contain extremely fine, repetitive features, such as small teeth, which require highly repeatable processes within 10 microns of repeatability,” Andres says. “For many years, the only option for us to reach this level of precision in hardened steel was to hand-finish these features using diamond files. It was a long, arduous and exhaustive process that was not repeatable.”

The addition of three vertical machining centers (VMCs) enables Feintool to keep up with increased hardmilling demands. Also, the quality of tooling exiting these VMCs has limited the amount of hand work, according to company officials, reducing the likelihood of human error, decreasing lead times and extending tool life by as much as 40 percent.

Since investing in vertical machining centers (VMCs), V33i models from Makino, the company has been able to reduce handwork by as much as 30 percent, leading to extended tool life, less variability, greater labor efficiency and substantial cost reductions, according to Andres.

Enhancing Tool Quality with Precision VMCs

Feintool’s first investment in high-speed hardmilling occurred in 2008, following a series of collaborative tests developed and conducted alongside the company’s Japanese division. The tests were comprised of 3D models of 64-HRc components featuring fine-tooth features, similar to automotive seat-recliner components submitted by many of its customers. Performance of the V33i exceeded Feintool’s expectations, achieving the desired tolerances and quality while producing the fastest cycle time among all suppliers evaluated, according to Feintool officials.

Designed for long hours of unattended hardmilling, the V33i delivers high-speed machining with high accuracy, efficient chip removal and simple operation, according to Makino officials. Its standard 20,000-rpm spindle features a core-cooling and under-race lubrication system to minimize thermal distortion at high spindle speeds. Additional rigidity is achieved with the integrated construction of the spindle and drive motor, which cuts down on vibration during high-speed operation.

Controlling the impact of machine movement on thermal characteristics reduces temperature impact on the machining process and yields sustainable, long-term, dynamic accuracy. As such, temperature-controlled lubricant is used throughout the machine to minimize thermal growth during cutting, according to Makino officials. Cooled elements such as core-cooled ballscrews, lubricated ball nuts, a servo-motor cooling-jacket system and temperature-controlled passageways all work to provide structural temperature control.

To bring preheattreated-machining capabilities inhouse, Feintool has invested in additional VMCs. The result, according to company officials: quicker turnaround for customers and higher-quality milling.

Since this initial investment in one machine, Feintool’s business has grown substantially, requiring the company to add a third shift to keep up with demand. By 2014, customer demand had reached Feintool’s maximum capacity, which led the company to invest in a second V33i. The tool magazine on this machine was increased from 25 to 60 tools to support greater capacity and redundant tooling for extended, unattended machining operations. Feintool continued its expansion of hardmilling capabilities with the addition of a third V33i in 2015.

Repeatable Toolwork Limits Manual Finishing

“Fineblanking tools require a very fine cutting edge in order to cut sheetmetal accurately during the stamping process, so we often coat finished chamfers with a TiCN coating to increase the tool’s performance,” explains John Castle, senior supervisor of tool maintenance at Feintool. “When it comes to hand-finishing the cutting edge, each toolmaker might have a different method or approach, which increases the likelihood of inaccuracies in the final tool.

“If any inaccuracies are discovered during the stamping process, the tool must be sent back to the toolroom to remove the coating, reradius the cutting edge and add another coat,” he continues. “This adds up to several hours of downtime for our pressroom. The tool quality coming directly out of the V33i machines has limited the amount of handwork, reducing the likelihood of human error and decreasing lead times, and extended the life of our tools by as much as 40 percent.”