New Hot Knife Design Cuts High-Tech Fiber
Hot-blade Cutting Offers Benefits Over Scissors
Editor’s Note: Photo available by contacting Sandy Frinton, firstname.lastname@example.org, (845) 454-3895
Fort Mill, S.C., Dec. 22, 2008 – High-tech organic fibers such as aramids are used in a variety of nonwoven and fabric applications where strength, toughness, abrasion resistance and resistance to cutting are important parameters. In safety applications such as personal protective equipment, gloves, chain saw chaps, protective apparel and others, the resistance of the material to blade cuts is essential to success of the product.
Now the downside – during cut-and-sew operations to assemble the final net shape, resistance to cutting by knife blades can be a problem and can increase production time and costs.
One of the more recent entries into the market for protective materials is Vectran®, a liquid crystal polymer fiber made by Kuraray. Vectran fiber’s unique properties provide a number of benefits over aramids including superior strength, abrasion resistance and cut resistance. Vectran fiber can provide product designers and engineers with an alternative to aramids for applications from composites used in aerospace to flexible coated fabrics and protective apparel.
While cutting thick Vectran fabric samples for laboratory testing, Kuraray noted a rapid degradation of cutting speeds as blades dulled due to the hard nature of the LCP polymer used to produce the fibers. Because of the difficulty experienced in cutting Vectran, Kuraray turned to the German-based equipment manufacturer, HSGM (Heissschneide- Geräte und -Maschinen) to make recommendations for possible heat cutting of Vectran. Material samples were sent to HSGM’s testing lab in Walluf, Germany.
In heat cutting, the blade of the cutting tool is heated to a temperature above the zero-strength temperature of the fiber. After several cutting trials, HSGM was able to cut Vectran fabrics at a good speed and produce a welded edge, when using the proper heat settings and recommended blades.
“We found the Vectran very difficult to cut by conventional means,” said Stephan Herrmann, general manager, HSGM, Germany. “However, because of the fiber’s unique thermal properties we were able to soon find the right combination of heater and blade design. Comparing hot cutting of Vectran to hot cutting aramids, Vectran could be hot cut easier and a little bit faster.”
Heat cutting provides economic and time savings over traditional mechanical cutting techniques that typically require additional finishing with a sewing machine or sealing. Heat cutting combines both processes into a single cost-effective operation.
While hot cutting of synthetic fabrics, ropes and belts continues to gain importance in the manufacturing process and in the garment industry, cutting high-tech materials has been a challenge. By using hot-cutting methods over traditional hand-cutting techniques, overall cutting speeds can be improved and the high cost of blade replacement greatly reduced.
“With its high cut resistance and other properties, Vectran fiber provides an alternative for product designers and engineers who want to use high-tech materials but have had problems cutting aramids,” said Forrest Sloan, Ph.D., manager, international marketing, Kuraray America’s Vectran Division.
Hot-knife techniques can also be used with Vectran in rigid composite laminates. Organic fibers such as aramid or LCP often leave a rough or ragged edge after net-shape cutting with a high-speed saw because the fibers are difficult to cut. The edges of composites containing Vectran can be melted using a hot knife to remove the excess fiber, resulting in a cleaner edge and more acceptable finished part.
Through its new materials testing program, HSGM helps companies select the right cutting machine and blade for their specific applications. The company recommends two of its units for cutting Vectran, the HSG-1-VW or HSG-03-VW, with blade type HSS15°-7mm.
HSGM’s cutting system works by heating a blade with a transformer for up to eight seconds at about 600 degrees Celsius, melting all thermoplastic fabric that comes into contact with the tip. A consistent sealed edge is formed in a webbing when the individual weft and warp threads naturally flow into each other.
Heissschneide- Geräte und -Maschinen, an independent organization within the ENGEL Group, has been in operation since 1977. The company develops, produces and sells heat cutting machines and equipment, fixtures and machines for cross-directional and straight-line cutting, automatic length cutting machines for ropes and belts, form cutters and form cutting machines, soldering and Styrofoam cutting equipment as well as single-phase and three-phase transformers. For the US market: visit www.hsgmusa.com and for European and worldwide markets: visit www.hsgm.com.
About Kuraray America, Inc.’s Vectran Division
Based in Fort Mill, S.C., the Vectran division of Kuraray America, Inc. produces Vectran® fiber, the world’s only multifilament polyester-polyarylate yarn melt spun from liquid crystal polymer (LCP). Vectran fiber is used in a wide range of applications where strength, durability and dimensional stability are critical to performance and safety. For more information, please visit www.vectranfiber.com.
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