The principle is somewhat reminiscent of pottery – Leifeld has developed a new machine for wheel rim production using flow-forming, which for the first time also works with inner rollers: Instead of hands shaping from the inside and outside in pottery, rollers are used instead of a lump of clay a sheet, a round blank or a blank.
“Market developments and our own aspirations continue to drive the flow-forming process forward,” notes Oliver Reimann, CEO at Leifeld Metal Spinning GmbH. The company develops machine tools for chipless metal forming that are used worldwide in the automotive, aerospace, energy and other industries and in various industrial applications. The managing director recognizes trends in the automotive industry in particular.
Growing design complexity, larger wheels with a simultaneous increase in the number of variants, and increasing cost pressure are just a few of the many other arguments in favor of using the Leifeld WSC Flex. In wheel production, it offers far-reaching potential for increased productivity while reducing costs and thus relevant competitive advantages for OEM and after-sales wheel manufacturers.
“Manufacturers must be able to react very flexibly to these market developments,” Oliver Reimann is certain. For the production of wheels, flow-forming gains additional relevance due to this novel technology. “With our technologies and machines, we can design passenger car rims made of cast aluminum so that they are significantly lighter than conventional wheels and at the same time more resilient,” promises Benedikt Nillies, Technical Director at Leifeld. With such wheels, OEMs can more easily meet the legal requirements for CO2 reduction: Less weight means more range, which means less fuel or energy consumption.
Additional material reduction thanks to increased strength
Aluminum rims are often cast or forged in one piece. The flow-forming process improves the microstructure of the material, which significantly increases the final strength of the rim after heat treatment. “We have the ability to reduce the material cross-section at certain points and flexibly adapt it to the load requirements of the wheels,” says Nillies. “With this process, we achieve an improved microstructure.” The resulting increased strength enables additional material reduction. Wall thicknesses and wheel geometries can be optimally adapted to the requirements of the wheel – this allows flexible wheel design and maximum weight savings.
Flexible without tools
“How can we support our customers even better in responding to market trends such as the increasing diversity of variants or just-in-time production with a high degree of flexibility? That’s what we asked ourselves here in the team,” says Sales Director Harald Knechtel. For this purpose, Leifeld has further developed the well-known flow-forming process. “The Leifeld WSC-Flex technology works flexibly without tools,” describes Harald Knechtel: “The principle is somewhat reminiscent of pottery. The shaping movement of the hands is similar to the axially and radially movable inner and outer rollers.”
With the process, the user is very flexible and can produce different rim diameters, profiles, wall thicknesses and rim widths. While classic flow-forming uses one tool per rim type, Leifeld WSC Flex does not require any product-specific tools. This also means that there are no setup times. The procurement costs for tools, warehousing and maintenance are completely eliminated. “On average, two to three setup processes are carried out per day with a standard machine, which can take about 1.5 hours each per setup process due to the preheating of the tools and the run-in of production,” Harald Knechtel calculates. “The use of the multifunctional chuck makes our new process particularly suitable for chaotic production from batch size 1.”
Profitable all along the line
According to customer-specific performance requirements, Leifeld offers the WSC Flex with different workpiece change concepts and with a varying number of rollers. The new machine achieves comparable cycle times to tool-based machines. A previously unavailable function is added: The new process allows a completely cylindrical area to be formed, which increases wheel stability.
“Our WSC-Flex technology is a world first with high market potential. Our customers will achieve at least a 15 percent increase in efficiency, as well as around 10 percent energy savings,” promises Sales Director Harald Knechtel. “We have focused primarily on customers who manufacture cast wheels. For the production of forged passenger car wheels, the new process brings just as many advantages.” Leifeld’s WSC Flex technology allows users to chaotically manufacture wheels from 18 to 24 inches.
CEO Oliver Reimann is pleased with the positive market response: “The patented Leifeld WSC Flex joins our portfolio as another innovation. At last, the wheel industry is able to flow-form rim profiles with enormous flexibility, which previously could only be produced with expensive tools and increased effort.”