Metal Stamping Evolution Brings Challenges

November 1, 2019


From the growth of automated and intelligent technology to new consumer demands, manufacturing faces many challenges that will require change in the way it does business, according to Laurie Harbor, president, of Harbour Results, Inc. A recent Harbour IQ Pulse Study, looking at performance across different manufacturing sectors, indicates that most shops are not prepared for the changing landscape of manufacturing. This evolution requires of industry best practices for delivering future success in emerging manufacturing technologies.

Industry 4.0

One example of a manufacturing technology in need of best practices is Industry 4.0, the umbrella moniker for all things related to improving processes and products by collecting and using real-time process-related information from factory equipment with network-connected sensors, software and cloud computing. When it comes to sheet metal forming processes, Industry 4.0 best practices are lacking. Jason Rsyka, chief engineer for North American stamping operations at Ford Motor Company, and his team, are striving to change that by recognizing and implementing new technologies to monitor sheet metal forming in real time. That feedback will then provide real-time directives to the press equipment, while also providing intuitive information to multiple levels of users on the influence of inputs variables on the process.

To arrive at Industry 4.0 best practices requires of teams such as Rsyka’s, concerted implementation of sensors, closed-loop process control and machine learning. Moreover, the application of real-time nondestructive evaluation tools that measure incoming material properties (e.g., yield strength and tensile strength), blank thickness, lubrication-film thickness, blank edge movement in the draw station, wireless monitoring of nitrogen pressure, and thermal imaging (tooling and stamping temperature), provide metal stampers with new opportunities to improve business performance, boost product quality and optimize production.

Metal AM Processes for Tool & Die

The manufacturing demonstration team at Oak Ridge National Laboratory (ORNL) continues working on metal additive manufacturing (AM) processes for tool and die applications, an effort that began three years ago. ORNL’s efforts are supported by the DOE’s Advanced Manufacturing Office (AMO), which focuses on helping “early-stage research to advance innovation in U.S. manufacturing and promote American economic growth and energy security.” Producing metal stamping die components using AM processes such as 3D metal printing reduces raw material required to produce die components by adding metal to near net shape, rather than removing material. Using AM reduces the required machining process by up to 50 percent, allowing for shorter lead times and faster reaction time to changes, helping to make U.S. tool and die makers more competitive in the marketplace.

When machining die components, whether wrought tool steel or 3D-printed sections, the importance of the structural dynamics of the tool holder—the interface to the machine spindle—in relation to selecting milling parameters deserves consideration. Professor Tony Schmitz, University of Tennessee, Knoxville, has studied relationships between the structural dynamics, cutting force, chatter and machining accuracy through the application of artificial intelligence. The goal of his work: Demonstrate how chatter-free milling parameters can be chosen at the process planning stage (programming) to provide first-time-correct performance.

Lightweighting

Sheet materials also continue to evolve due to automotive lightweighting initiatives. One issue: edge stretchability. Edge stretching is a sheet metal forming mode prevalent in various automotive stamped parts where stampers engineer and design the blank with strategically placed holes to allow material flow into difficult-to-form areas commonly seen in automotive vehicle parts such as body-side outers, door inners and lift gates. Aleris, an aluminum sheet producer, is working to determine how the blanking process affects the edge formability of an expanding hole in aluminum sheet. In this study, aluminum blanks (5XXX and 6XXX alloys) with a cutout in the center are formed over a large flat top punch. The cutouts, produced using machining, laser cutting and shearing at different clearances are formed until edge fracture occurs. Edge strains and forming depth between the edge conditions and alloys are compared to see how the blanking method could affect formability of these alloys. The goal: Provide a tool to help predict edge stretch failures in commercial stamping-simulation software.

Another lightweighting issue that confronts metal stampers is the joining of multi-layer dissimilar materials with a single weld from a combination of materials: steel, aluminum, brass, magnesium, and cast or sintered metals. One promising solution: friction stir welding, created between workpieces in relative motion to each other. Friction creates heat, leading to a plastic (non-melting) state at the interface joint, with workpieces forged together. With this highly efficient method, about 95 percent of mechanical energy transfers as heat into the workpiece, where shielding gasses and filler materials typically are not needed. Imperfect welds also can be captured in real-time and reported across the entire process, allowing for quick adoption of process improvements.

The persons and technologies mentioned here are just a sampling of new, emerging and maturing technologies being presented and displayed at PMA’s Metal Stamping and Tool & Die Conference, January 28-29, 2020 in Nashville, TN. For more information or to register for the event, visit www.pma.org/mstd-conference/ or contact Marianne Sichi. MF

Industry-Related Terms: Alloys, Blank, Blanking, Brass, Center, Die, Draw, Edge, Forming, LASER, Shearing, Thickness, Wrought
View Glossary of Metalforming Terms

Technologies: Sensing/Electronics/IOT

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