New hot knives can cut high-tech Vectran fiber
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.