Page 10 - MetalForming July 2009

TechUpdate
Advancements in 3-D Laser Cutting Improve Trimming of Hot-Stamped Steels
Driven by the automotive industry’s
need to improve safety, reduce vehicle
weight and increase fuel economy, the
steel industry has developed numerous advanced-high-strength steels and hot-
formable steels. Hot stamping with die
quenching of boron steels appeared at the
end of the 1990s, and since then, the
process—also called press hardening or
hot forming—has become popular for
forming complex, high-strength automo-
tive components, including A- and B-pil-
lars, door sills and bumpers. With so
many advantages and very few draw-
backs, it is easy to predict that the use of
hot-formed steels in the automotive industry, and possibly in other industries, will dramatically increase in the coming years.
This new type of metalforming requires a new generation of 3D processing equipment for trimming and piercing the hot- formed parts. While traditional mechanical equipment used to trim and pierce the formed parts can result in extremely high tool wear, laser-beam cutting of hot-formed parts, according to
Antonio Rotunno, director of technical services for Prima North America Inc., Chicopee, MA, offers manufacturers a way to easily and accurately adjust trim lines and feature size or location. And, the ther- mal reaction required for laser cutting is unaffected by the steel strength.
In 1995, Prima installed three of its Rapido five-axis laser machines at SSAB HardTech in Sweden (acquired in 2004 by Gestamp Automacion), to trim hot- stamped parts. Prima also has deployed 3D laser-cutting machines in hot-stamp- ing applications elsewhere in Europe and in North America.
“Back in 1995,” Rotunno says, “hot-formed parts were laser- cut using oxygen as the assist gas. Cutting speeds were around 100 in./min. Today, lasers with higher beam quality and power to 5000 W allow cutting with an inert assist gas such as nitrogen, with speeds in excess of 780 in./min. The cut edges are free from oxide and therefore are weld- and paint-ready with no secondary operations required.”
Prima North America: 413/598 5200; www.prima-na.com
Vision Systems Ensure Saw-Blade Perfection
At Switzerland-based saw-blade manufacturer Scintilla, a Bosch Power Tools division, a high-performance vision system ensures that jigsaw and reciprocating saw blades leave the pro- duction plant free of defects. As many as 700 different mod- els of jigsaw blades, all with different paintwork, imprints and shapes, are produced at the plant, and each requires complete inspection. To automate the quality-control process, the com- pany invested in a vision-based solution supplied by Cognex (with U.S. operations in Natick, MA), installed by Swiss integrator Compar AG.
In the finishing area of the Scintilla plant, operators insert eight fabricated jigsaw blades into a fixture mounted on a rotary transfer machine, which positions the blades for inspection. Dur- ing the first phase of inspection, the vision system inspects the base paint for color and discoloration, as well as for the presence of dirt, scratches or fine lines down to 0.2 mm in size. A sec- ond inspection phase then checks the pad imprint on the saw blades to determine the quality of the printed text or graphics.
An important feature of the vision system: The individual shapes of each blade type need not be manually positioned and adjusted. Rather, the shape of the saw blade need only be taught to the system once and then saved. The individual character- istics of each blade—edges, dimensions, shapes, angles, arcs and shades—are isolated and identified. The three-dimensional
relationships between these features of the learned image then are compared against the real-time image.
The Cognex quality-control station operates on a three- to four-shift basis and checks 60,000 saw blades each day. The machine runs on a 4.5-sec. cycle, with visual inspection tak- ing 1.8 sec.
Cognex: 508/650-3000; www.cognex.com
Robot Maintenance, Repair via the Web
The new RobotPro Web Edition from Motoman Inc., Dayton, OH, facilitates preventive maintenance, alarm-code troubleshoot- ing and repair procedures on Motoman robots with NX-series controllers. The software is tailored to each specific robot model and is structured in a user-friendly format with illustrated, step- by-step procedures, according to company officials. Being web- based, the software can be used on a laptop computer, mak- ing the system portable.
RobotPro Web Edition includes descriptive test and repair procedures with illustrative graphics and provides a preventive- maintenance schedule with links to procedures, printable for use as a convenient checklist. Interactive troubleshooting is
8 METALFORMING / SPECIAL ONLINE-ONLY ISSUE 2009
www.metalformingmagazine.com