Feintool Reduces Jig Grinding and Handwork for Fineblanking
Fineblanking is a unique manufacturing process, whereby millions of very accurate stamped parts can quickly be produced. The process to fineblank is not easy, however, so only a select few attempt it.
Punches used to form parts in fineblanking are constructed of materials hardened to 60 HRc or higher, due to the hundreds of tons of pressure and millions of repetitions they are subjected to. And while the hardness provides for durable, long-lasting punches, machining them with high accuracy and efficiency is challenging. Often, fineblanking punches have had to be produced using hours of handwork, slow jig-grinding processes, sinker EDM operations or outsourcing to specialty milling houses.
“These aren’t your typical punches,” says Beat Andres, Feintool Cincinnati’s tool room manager. “We’re talking about parts with features and tolerances that typical stamping processes are incapable of producing, and sometimes parts made of hardened materials themselves. These punches have to be utterly accurate because the parts we produce have to be perfect.” Many parts made using the fineblanking process become critical components of safety equipment for automotive, marine and other applications. They are parts that are made to exacting tolerances to reduce the chance of failure.
“Our machinery must be able to hold tighter tolerances than the punch itself, which in turn must be more accurate than the final part,” continues Andres. “For decades, handwork and jig grinding were the best options available for obtaining our required accuracies. Hardmilling technologies have come a long way since then. Our purchase of a Makino V33i has dynamically changed our shop floor, impacting every step of our processing from programming to final part production.”
Global and Growing
Founded in Switzerland in 1959, Feintool began as a pioneer in the production of fineblanking machinery. Today, Feintool is a worldwide, publicly owned company with four divisions—Feintool Technology Ltd. Lyss, Feintool Parts & Components AG Lyss, Feintool Research & Development AG and Feintool International Management AG. In addition to producing and selling fineblanking machinery, Feintool’s technology centers, located in Switzerland, USA and Japan, have become full in-house production facilities, supporting all standard platform strategies of the automotive and electronics industries.
Feintool Cincinnati started operations in 1978 with five fineblanking presses, a production area of 45,000 square feet and 19 employees. When it was founded, the overriding objective was to develop new application areas for fineblanking on the American market, where the technology was still largely unknown. Today over 20 presses rated at up to 10,000 kN are in service, the production area has tripled in size to 135,000 square feet and a workforce of over 200 guarantees products of a consistently high quality.
Feintool Cincinnati runs its own Technology Center with prototyping, tool engineering and toolmaking that are also available to Feintool Tennessee. It conducts an intensive exchange of part production knowledge with the Feintool System Parts locations in Europe and Japan, from which all customers profit, and their facility contains all the necessary equipment for full in-house production from programming to finished part.
“Our one-stop-shop capabilities make it easy on customers,” says Andres. “We receive the designs and take care of the rest. We optimize designs specifically for the fineblanking process, machine the punches and fineblank the final parts on presses built by our own company.”
Fineblanking is an advanced blanking technology that produces no fractures when shearing. A fineblanking press operates by compressing a sheet of material, such as copper, steel, brass or aluminum, under a hardened tool punch, while applying a less forceful counter pressure against the punch. This counter force allows for a flatter, smoother surface than typical stamping processes. Many fineblanked parts go through multi-part stamping processes, and nearly always come out of the machine ready to be used.
Fineblanking is praised for its excellent dimensional control, accuracy and repeatability throughout a production run. Compared to other stamping processes, fineblanking is a more economical solution for high-precision parts in large quantities.
“We began testing and evaluating hardmilling machines in 2006, jointly with Feintool Japan, to find one that would meet our primary concerns of repeatability, accuracy and speed,” says Andres. “It took time to find the right investment, including pressure from our company headquarters to purchase a Swiss mill. Our Japanese facility purchased a Makino V22 in 2006 that performed beyond our required specs, and combined with an impressive Makino hardmilling presentation we attended at IMTS 2006, our decision became much easier.” Feintool’s initial Makino product of choice was a V33 vertical machining center, but upon the release of the new V33i in 2008 the answer to their machining needs was clear.
“The V33i is currently our busiest machine, operating nearly 24 hours a day, even unattended,” says Andres. “With high-speed milling capabilities in shop, we’re achieving 30 Ra surface finishes straight out of the machine, reducing lead-times by up to 85 percent on some previous jig-grinding applications, performing 90 percent of our previously outsourced work in-house, and are experiencing considerable reductions in lead-time, reduced manual labor, and in several cases producing higher quality parts and longer-lasting punches.”
High-Speed Hardmilling Brings Efficiency in Tough Materials
“The capabilities of the V33i have enabled us to hardmill a number of our previous jig-grinding operations, saving us time, money and manual labor,” says Phil Porter, Feintool NC programmer and V33i operator. “And while some jobs still demand jig-grinding finishing, the V33i is used to rough and semi-finish punches with dramatic reductions in cycle time compared to a full jig-grinding process.”
A transmission component punch produced for a leading off-road vehicle manufacturer was previously produced solely on the jig grinder, requiring over 40 hours of machine time. By completing the roughing and semi-finishing to within 0.050mm of the finished punch on the V33i, Feintool was able to reduce the total machining time to less than 10 hours while still achieving the required 0.0025mm tolerance.
“High-speed hardmilling has provided both the speed and dynamic accuracy required for a large number of tool components,” says Porter.
Previous to purchasing the V33i, Feintool also relied on slower EDM technologies in hardened materials. Today, the company is able to hardmill many of these EDM applications, reducing machining times.
“Tooth punches that once required two-day lead-times are now produced in just two to three hours,” says Porter. “A clutch-plate punch once machined using wire EDM is now completed on the mill 50 percent faster.
“Since investing in high-speed hardmilling, we’ve done all that we can to avoid the use of sinker EDMs. Don’t get me wrong. Sinker EDM can accomplish very tight tolerances and geometric features, but in the time it takes to produce graphite tooling and burn the application, we could already have final parts stamped and out the door by using the mill. For instance, a seating adjustment punch that required a week with Ram EDM, including the graphite tooling production, can now be completed on the mill in just one hour. That’s a huge savings for us, and a great benefit to our customers.”
Reduced Manual Labor
“We purchased a hardmilling machine with the intent to reduce lead-times,” says Andres. “What we got was near-jig- grinding accuracy, labor-free surface finishing, unattended machining capabilities and improved punch quality.”
The V33i’s near-jig-grinding positioning accuracy has provided greater flexibility in tooling selection, enabling Feintool to use endmills as small as 0.3mm for more precise cutting features. “The V33i can produce virtually any surface finish we need with little to no hand finishing required,” says Porter. “This has allowed us to significantly reduce lead-times and increase manual labor efficiency by over 40 percent.”
A recent punch produced on the V33i required 160 teeth to be machined along the exterior radius, each featuring a 45-degree by 0.020-inch chamfer. Previous machining of this punch was performed using an EDM and required a full day of hand finishing using a diamond file to achieve the proper chamfer accuracies. Today, this punch is completed on the V33i in 2.5 hours.
“The V33i achieved the tight chamfer geometries, cutting each tooth identically and exactly to spec,” says Porter.
Punches produced on the mill have also resulted in improved punch quality, allowing longer punch life than with other processes. This is due in part to the V33i’s ability to use a wide range of spindle speeds to hardmill using the smallest of endmill diameters for very small geometry radii.
“The spindle of the V33i has provided sustainable rigidity throughout a wide range of spindle RPMs, which led to improved tool life,” says Porter. “With the 25-tool capacity automatic tool changer and chip-removal features, I can walk away from the machine for hours, worry-free.”
No Experience? No Problem
Porter was the first to experience hardmilling at Feintool Cincinnati, but quickly became the resident expert, thanks to Makino’s tech transfer program.
“Before stepping in front of the V33i, I had never operated a milling machine in my life,” says Porter, who worked closely with Makino application engineer Ken Werbrich for one-on-one training.
“Makino’s training and one-on-one assistance was incredible,” says Porter. “I had the machine running by myself in a matter of days after installation, and was performing difficult jobs in a matter of weeks.
“Ken’s training was extremely valuable. Today, I’m very comfortable operating the V33i, and continue to learn and share information about the machine with other members of the Feintool team. In just a matter of months, I’ve gone from having never operated a mill to training a second shift.”
Milling the Future
“We have big plans for further lead-time reduction using high-speed hardmilling,” says Andres. “With more time and experisence, we plan to move most full jig-grinding punches to the V33i. In addition, we plan to further our milling capabilities with a second Makino and an automation solution for further lights-out machining capabilities.
“Milling is clearly the future for our business. Our hardmilling experience so far has proven that we can obtain the same or greater accuracy as we have with our EDMs and jig grinders, but with vast improvements in lead times and punch quality.”