- June 01, 2010, By Sam Jones, American Cutting Edge
Very thin surface coatings can be applied to nearly any knife or blade. Almost 20% of slitting customers choose to have an after-market coating applied to their blades.
Why? The main purpose of a coating is to increase the wear life of a blade or knife.
Increased wear resistance is achieved through coatings in two ways: The coating will increase the hardness of the cutting edge, and the coating will fill out the small valleys or ridges that form during the sharpening/grinding process.
The reduction of these grind lines provides a more uniform and smooth cutting surface, increasing blade life and wear resistance. Because coated slitting blades are both harder and smoother, friction effectively is reduced; performance and life are improved significantly.
Coated slitting blades increase production by reducing machine downtime due to buildup on knife and razor edges; tool breakage; scrap rates by holding close tolerances and finishes; and tool costs by decreasing the need for replacement blades. This translates to increased productivity, speeds, and feeds by as much as 50% in some industries, all going straight to your bottom line.
Many coatings are applied with a proprietary process layered on with very light coatings only angstroms thick, building the final result and providing greater control over thickness and uniformity. The processes and equipment used allow the blades to be coated at temperatures less than 250 deg, in many applications, assuring there is no annealing or softening of the substrate and no warpage to affect dimensional stability.
Typical coatings increase wear life as follows:
Titanium Nitrate has a bright gold surface color. TiN provides the least added wear life to blades but can be a good choice when price is critical and some wear resistance is needed. TiN typically will cost less, depending on blade size and quantity, but the added wear life can be 5-10 times longer than a carbon steel or stainless steel blade or knife.
Titanium Carbide has a gray surface color. TiC can be a high-performing surface coating and may add additional wear life of 20-30 times over a standard carbon or stainless blade or knife.
- Boron Carbide
This black-colored surface coating often is referred to as “ceramic” or “extreme.” It is one of the industry's biggest-selling coatings. The added wear life can be 50-plus times longer than a carbon steel blade or knife.
Usually a clear coating, DuPont's Teflon generally is used to increase the lubricity of the blade surface. It can be good for adhesive cutting applications to keep the blade edge and surface free from “gumming up.”
A number of coatings are FDA-approved and allow converters to run tool steels in applications that typically would have been “stainless only” in the past.
Industrial blade specialist Sam Jones, sales manager of American Cutting Edge Inc., Centerville, OH, has spent the past five years as an industry consultant for blades and custom blade applications process, design, and operations. Contact him at 888-282-3372; firstname.lastname@example.org.