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Q: Provide a cost/benefit analysis on carbide vs. diamond tooling.
Gene Veening, president, Royce//Ayr Cutting Tools Inc.: Cost and benefit will vary depending on application and material being cut or profiled. For the purpose of comparison, solid wood raised panels are a good example because they account for a large percentage of tooling cost in door production.
Initial purchase price of diamond raised panel tools are generally six to eight times that of carbide with a benefit of 200 to 300 times the tool life. Annual tooling cost per unit is dramatically reduced when using diamond tooling.
Unit cost of raised panels is reduced even further when finishing costs are considered. Diamond tools provide higher quality and more consistent surface finishes, resulting in decreased finishing costs.
Linda Wyant, vice president, Safranek Enterprises Inc.: Diamond tooling is designed for dedicated machines doing the same thing day in and day out. For a machine that is going to do one thing for its entire life, diamond tooling is an effective way to reduce downtime caused by tooling changes. Less downtime equals reduced overall production costs. Carbide tooling doesn't have the ability to last as long as diamond, but carbide insert and quick change tooling have the ability to reduce tooling downtime and/or restart time over braised solid shank tooling. Carbide insert tooling is becoming more versatile, and as it does, it could easily become the cost-effective choice on dedicated machines.
Tom Walz, president, Carbide Processors, Inc.: I think diamond has a better cost/benefit ratio, if you can fully utilize it. Diamond is sort of like a semi and most folks only need a pickup truck.
In the tool spectrum, there are a couple hundred materials between diamond and carbide. When we started developing ceramic saw tips, we used materials near the diamond end of the spectrum.
Our first ceramic saw tips (Cermets) worked really well, but they weren't successful. They would run 10 to 20 times as long as carbide, but they had many of the same disadvantages as diamond in that they were fragile, hard to get, very hard to sharpen and expensive to buy. Our second generation (Cermet 2®) focused on tips that could be used just like carbide, were harder to break than carbide and ran about five times as long as carbide for about the same price.
Provide a comparison of which tool type works best with which materials.
Veening, Royce//Ayr: As a general rule, diamond tooling will out-perform carbide when machining clean/consistent material. Diamond tools have been widely used for years to machine composite materials such as MDF and HDF. Modern diamond technology now produces tools that excel in solid wood machining.
Materials such as melamine and veneered particleboard panels are often better suited to carbide tools due to inconsistencies in the material core. In some instances these materials may still be cut with diamond, but the process must be more carefully managed.
In panel saw applications, both diamond and carbide blades can be used in conjunction to achieve the best possible performance and tool life. Diamond scoring saws used to cut the melamine layer and carbide main blades used to cut the panel core are often the best alternative for panel saws
Wyant, Safranek: Diamond tooling has always been the choice for cutting abrasive materials. Air- or liquid-cooled diamond tooling will outlast all other tooling in a hostile environment. There is no magic formula to determine which type (carbide or diamond) of tooling would be the best choice for any given situation. There are factors to always consider when making a tooling choice: material, ease of making tool changes in said machine, and how long the run is. This information vs. the cost of tooling choices will help determine which would be the most cost-effective.
Walz, Carbide Processors: I think diamond would be best where you can run the same tool for years in very clean material, where there is no possibility of foreign objects. Carbide is definitely best for throw-away tools where price is the only consideration. In the middle it gets more complicated.
A great deal of carbide is sold based on "C" grades from World War II. C-1 is tough and C-4 is long wearing. Dr. Stewart identified corrosion as a factor and increased the list to four factors affecting tool life. We use a list of 14 factors affecting tool life, which gives us the opportunity to specify a grade that will run longer than carbide in almost any applications. The MDF grade is different than the sawmill grade, which is different than the metal cutting grade.
We can specify a grade better than carbide about 90 to 95 percent of the time.
For more on what Veening, Wyant and Walz had to say on this topic, log on to wooddigest.com.
Q: How do the tool geometries of carbide and diamond differ if you are cutting the same material. What about spindle speed . . . is there a variance between the two tool types?
Veening, Royce//Ayr: Normally, cutting angles on carbide tools will be designed to exceed those on diamond tools simply because of the difference in cutting materials; PCD is much harder and, therefore, a more brittle material.
However, Shear angles can be maintained to achieve excellent cutting finish in either material. Feed speeds or rpm are similar for both materials as long as the tools are perfectly balanced and the material to be cut is free of loose knots or foreign objects. With diamond, excellent finish can be obtained for a very long time especially on solid hard and soft woods, keeping in mind that the right calculations must be done in order to maintain a constant chip load.
Wyant, Safranek: IF, and that's a big if, all things are equal — machine, material, tooling, environment — there should be little difference between carbide and diamond tooling. But in the real world, things are seldom equal. For example, most, when using diamond tooling, will air or liquid cool the tooling, while you will seldom see anyone air or liquid cool carbide tooling. Again, you will see diamond tooling being run at optimum speed because testing was done first to determine this, while carbide tooling will just be run at whatever speed is chosen. All things being equal, there is little difference between the two when it comes to spindle speed and travel speed.
Walz, Carbide Processors: We designed our materials so they could be run just like carbide. In free-fall cutting tests, they can be fed about 50 percent faster than carbide, but almost no one takes advantage of this because you have to balance the line.
What we do find is a great number of people are not running the right tools. There are at least five parts to tool design: material being cut, material doing the cutting, tool design, machine design and how well the tool is made.
As an example, we took a panel plant trim saw from a 3 and 1 grind to a 9 and 1 grind and got much better edges. The 3 and 1 was a stock saw and the 9 and 1 was a custom saw blade, but the price was about the same. The delivery was a couple weeks on the custom saw blade.