Carbide Tip Wear
Traditionally a machining operation ran the hardest carbide grade it could in order to get the longest tool life. If the grade started chipping or breaking then the operation backed off into a tougher grade. A tougher grade meant larger grains, more cobalt or both.
Today’s advanced metrics and more sophisticated materials means that there are many more options for carbide saw tips. A shop can now save money on sharpenings and chipped carbide tips by trying an advanced grade of carbide.
Instead of just examining the cutting tool tip for wear or breakage the modern cutting tool engineer uses a much longer list. An example of some things to be examined might include: Wear, Macrofracture, Microfracture, Crack Initiation, Crack propagation, Individual grains breaking, Individual grains being pulled out, Chemical leaching, Rubbing affecting electrical potential, Part deformation, Friction Welding, Physical Adhesion, Chemical adhesion, Metal fatigue, Heat, Compression / Tension Cycling, and Tribology.
Advanced options to solve tool problems include micron and submicron grades, advanced alloy binders, various manufacturing operations and various coatings.
The first step in problem solving is still defining the problem accurately. Fortunately the development of inexpensive digital microscopes working off of laptops has greatly aided the process.
One recent example concerns saw blades trimming the edge of gypsum panels. Upon visual inspection the edges of the saw teeth showed very significant rounding clearly indicative of straight wear. Since gypsum is an extremely soft material this seemed to make sense. However the classical solution of using harder and harder carbide grades did nothing to solve the problem.
This is a photograph of one of the affected saw tips at 50 X magnification taken with a handheld scope costing about $150. The rounded area outlined in red was originally a sharp edge. It was at the end of a land which had been introduced as a design feature to help reduce wear. The rounding does look like classic, straightforward wear.
When the saw tips were examined at 200 X magnification it became obvious that there was an extreme amount of scoring and chipping on the cutting edges.
Analysis of the gypsum being cut showed that the “gypsum” contained between 2% and 10% anhydrite and quartz. This information, combined, with the photographic evidence prompted the selection of a much more advanced grade that resisted scratching and gouging thus greatly increasing service life. Increase the service life of your blades by using advanced grades of Carbide. Call us for a quote at 800-346-8274 or visit the Saw Tip section of our store.
Thomas J. Walz
Carbide Processors, Inc.
3847 S. Union Ave.
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