Friday, October 17, 2008

Burn requirement requires use of Kevlar threads

July 2007 was a significant date for mattress manufacturers; you may think to yourself why this date has any significance? These manufacturers had to comply with the new “burn” regulations by this date or face fines and penalties. These companies had to completely redesign there manufacturing processes and materials to meet these new standards. To meet these standards all the manufacturers are using Kevlar® thread to prevent the seams from opening and allowing the fire to get past the fire barrier. Some manufactures are also using silica infused fabrics as part of this fire barrier.
Thread clips and scissors may have to be modified to cut these materials. Kevlar® is used in body armor to prevent shrapnel and bullets from wounding or killing the person wearing it. The Kevlar® is layered upon it self over and over again, as the object tries to penetrate the surface the multilayer’s bunch together and keep it from passing through. To cut this material you must keep the fabric spread out, if it bunches up the scissors will not be able to cut it. This is accomplished by putting corrugations on one or both blades, there are many weaves and weights of these materials and the scissors and thread clips need to be optimized for the materials you are using. Our in house R & D department gets samples of these materials and finds the correct angles and corrugations need for each of their materials.

This material is very abrasive and these scissors and snips must be sharpened frequently, using a high quality, harder scissors (HRC) your time between sharpening increases. We use the Twice as Sharp® scissors sharpening system to sharpen the scissors and then we use the "Corru-Gator" to put the corrugations back onto the blades. You can also manually put these corrugations or teeth back on the scissors blade using a diamond corrugating or steel checkering file.

The Kevlar® thread requires a higher quality thread snip to cut it, the edge of this thread snip needs to be modified to cut the specific thread that they are using, the snip may require corrugations like the scissors do. The new high strength fishing lines are made out of Specra®, they are light weight and stronger than the old mono-filament fishing line and therefore more difficult to cut.

On a recent site visit to a medical chair manufacturer’s R & D department I found that they are having problems cutting the Kevlar® threads, Kevlar® and Nomex® fibers that they have to use to meet the changing government regulations. We found that the KAI scissors cut this non-woven fabric without problems as long as the vapor barrier remains intact during the chairs construction. At times this vapor barrier will separate from the non-woven fibers and then they must use scissors that have been modified to cut the Kevlar® fibers.

Contact us here at Wolff if you need help cutting difficult materials like these.

Kevlar® and Nomex® is a registered trademark of Dupont.
Spectra® is a registered trademark of Honeywell.
Twice as Sharp® is a registered trademark of Wolff Industries, Inc.

Purpose of this Blog

As a manufacturer of scissors sharpening equipment, scissors and shears we have worked to find the best way's to cut a multitude of hard to cut materials. We have helped develop these solutions working with manufacturers over the past 25 years.

These materials may be something like Kevlar®, Spectra®, Nomex® and Fiberglass. Trimming rubber & plastic flash, materials for composites like pre-prag and carbon fibers. Proper tools and scissors maintenance are needed to process poultry and other food products.

I will write updates as our technicians and salespeople encounter cutting issues and develop solutions to these cutting problems. Please e-mail me David Wolff with any questions that you may have, I would also love to hear from you any unique solutions that you have developed and with your permission would post those that pertain to this blog.