Page 16 - MetalForming December 2009

Increased Productivity
Before: 12 parts/min After: 18 parts/min 50% more
Before: 25 parts/min After: 40 parts/min 60% more
How much faster could your parts run?
Are you running parts on presses in the range of 300 tons and up?
Schuler’s unique ServoDirect Technology could take your output performance to a whole new level as well. Our calculation program can predict your potential with high accuracy.
Curious? Contact us and we’ll be happy to assist you in obtaining a free assessment of any part your company would like to investigate.
E-mail us at info@schulerinc.com.
Call us: 734-207-7200
Ask for ServoDrive Sales
Read more: www.schulerinc.com/SDT
Schuler.
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Continuous Coil-Fed Laser Blanking
14 METALFORMING / DECEMBER 2009 ONLINE
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nesting opportunities to maximize coil utilization and minimize engineering scrap. This is particularly evident when using common-line laser cutting.
There are other potential savings advantages that have not even begun to be understood. For example, consider the ability to nest two different parts of like thickness in the same strip. With laser cutting, the processor can change a part nest so that the same coil width is used for different parts of the same thickness, or it can nest different parts made from the same material thickness in a variety of different ways to mini- mize the scrap produced during blank- ing. There no longer are limitations to a set progression based on the length of the press bed.
Scrap Reduction
Typical overall engineering scrap for automobile body-in-whites (BIW) aver- ages a staggering 40 percent, unavoid- able because forming requires binder material to hold the blank with the proper tribology to control its successful flow by the punch in the die. This binder material, along with other functional holes in the final component, is trimmed out to have the exact dimensional shape per the end product’s design.
To enhance formability, the binder area sometimes receives favorable con- tour features. Trying to nest these con- tours in a coil progression to optimize material utilization results in engineer- ing scrap distributed between the blank- ing process and the post-forming process. However, since laser-cutting prefers the same contour features as the forming process—large-radius curvilinear features, rather than straight segments and angular features—it allows for more flexibility in parts nest- ing (see the figure), and results in the need for less binder area and draw beads. The net result, on average, is at least a 3 percent reduction in scrap per BIW.
From Automated
Blank Feed to Coil Feed
Traditionally, laser-blanking lines receive large rectangular sheets of vary-
ing thicknesses and cut them into smaller, nested contours. Automated shuttle tables and part-removal sys- tems reduce labor content and improve productivity.
Recently, manufacturers have been looking at the other side of the laser- blanking process. Coil-processing lines, in particular cut-to-length and multi- blanking lines, have had stacking sys- tems automated to feed laser-cutting systems and produce developed blanks.
The Automatic Feed Co. recently developed a process to feed coil strip directly into a laser-blanking line. The complete strip moves into the laser- cutting system and emerges out the other end as a completely developed blank. A dynamic profile conveyor allows the laser to make developed- blank cuts from the strip; the support- ing conveyor lanes dynamically sup- port the strip while avoiding the laser.
For simple blank profiles, the con- veyor lanes are adjustable to clear a path for laser cutting; for complex developed blanks or for systems that require a higher production rate, the conveyor lanes can be extended and retracted dynamically during cutting. The lanes also can be extended and retracted between partial feeds in order to progressively produce the blanks. Typical production rates are 5 to 10 parts/min. The use of a dynamic con- veyor also allows the processor to use different modes of operation—a start- stop feed mode or a continuous-feed mode.
Progressive Laser Blanking
At its simplest description, a coil- fed laser-blanking line employs multiple laser heads to concentrate the overall work in a smaller restricted area. Using numerous coordinated cutting heads multiplies the speed of the work and, therefore, optimizes productivity and throughput. The laser heads mount on a gantry, robot or stationary gimbals in multiple cutting cells that travel along the moving strip. The material is held by pinch rolls or other clamping devices that maintain tension in the strip, keep- ing the material tracked and flat. The