Page 20 - MetalForming-Dec-2018-issue

Materials and Processes
“Those producing parts from sheet- metal push materials to their limits, and testing machines enable such com- panies to double-check simulations and real-life results,” he explains.
Panel-Waviness Applications in Automotive
Through tours and presentations, we learned of various organizations employing testing apparatus to ensure
ideal sheetmetal performance during and after forming. For example, Voestalpine produces sheetmetal spec- imens to test surface waviness per a Volkswagen standard for autobody panels. Specimens are tested specifi- cally for long waviness, a condition that does not reveal itself on formed components until they are painted— by this point, corrections result in excessive scrap and time costs.
A 600-kN static materials-testing machine along with a deep-draw-test fixture, both supplied by ZwickRoell, are used for cupping tests on these specimens. A special feature of the test- ing system: a laserXtens extensometer with eight measurement axes. It meas- ures surface strain without making contact with the test material and stops forming at a set value. With this capa- bility, specimens need not be pre- marked, thus saving preparation time. Voestalpine is the first user of this tech- nology package and, should testing demand increase, it can be expanded to include an automatic specimen- feeding system.
Robust Testing Needed for Stronger Steels, Hot Stamping
As new steels approach and surpass tensile strengths of 2000 MPa at rela- tively low elongation levels (less than 10 percent), apparatus must be designed to provide all-important material testing and quality assurance. Another need for uniquely designed test equipment is the rise in hot-stamp- ing work for automotive. Mechanical tests often applied for hot stamping include tensile and bending tests as well as high-speed tests related to crash simulation and to measure high strain rates. Challenges abound in testing hot-stamped components, ZwickRoell’s Bob Donohue, regional sales manager, explains to MetalForming.
A current issue in automotive hot- stamping applications is process opti- mization, he reports, and optimization revolves around austenitizing and hardening that result from the heating and cooling inherent in the process. Key to optimization is the ability to determine material properties sur- rounding these stages. Actions may involve warm tests such as tensile and compression, and tensile tests per- formed on small specimens at room temperature. Why small specimens? Contoured hot-stamped parts often produce little space in key areas where ideal testing samples can be cut. Such small, yet hard test specimens do not lend themselves to traditional gripping
Eliminate Operator Contact with Sharp Metal Scrap
IMPROVE
Housekeeping
REDUCE INCREASE
Downtime Employee Safety
Automatically Remove Metal Scrap Away from Core Operations
Horizontal/Vibratory Conveyors
Visit us online at
prab.com/mf
Incline Steel Belt Traversing Conveyor Conveyors Load-Out Systems
CONTACT US
(888) 324.2576
sales@prab.com
18 MetalForming/December 2018
www.metalformingmagazine.com