Diamond tooling has proven to be a boon to the woodworking industry.
Advances in diamond processing techniques and machinery, and the worldwide expansion of diamond tooling manufacturers, have driven down the cost and made diamond polycrystalline [DP] tooling accessible to more users and a wider range of applications. With performance increases of 30 to 200 times over carbide, DP tools have a lot to offer an industry struggling for a comeback.
The popularity of diamond tooling for woodworking continues to grow as users are enticed by promises of longer runtimes and tooling costs that are more and more attractive.
Often users equate “diamond” with high quality, long run times, better finish and so on. While this could be the case, the Achilles heel of diamond tooling is its brittleness and susceptibility to damage as a result of vibration.
Vibration: Cause and Effect
Vibration primarily results from two sources:
1) An imbalance or eccentricity in the tool (or spindle) caused by inaccurate manufacture, service or maintenance, or poor spindle/bore fit.
2) The inadequate support for the workpieces from excessive overhang, insufficient clamping pressure or inconsistent feed.
Whatever the cause, the result is a progressive degradation of the cutting edge by slowly beating away the diamond particles rather than wearing them away. To maximize the benefits of diamond tooling, it is critical to review the application with your tooling supplier to ensure it is appropriate as a whole.
Plant management should recognize that high-performance tools require close attention and ensure operators are fully trained and educated in the proper handling of DP tooling.
The woodowrking machinery — including spindles, feeding mechanisms and hold-downs — and tool-holding/clamping devices should be regularly checked and maintained to ensure they are suitable for the applications. Buyers also should educate themselves, ask questions, look for precision-ground reference surfaces (shanks, bosses, collets, flanges, tool holders, etc.) and talk in terms of quality and tolerances with their tooling vendors.
Operators may recognize a knife with a cutting edge that “feels” sharp, but chips or produces an edge with scratches or an otherwise unsatisfactory finish. Many of these are the results of micro breakouts along the cutting edge that could be contributed to vibration damage. Users must pay close attention to tool maintenance — regularly cleaning and changing collets and tool holders to ensure precise clamping surfaces.
In router applications with a spindle rpm greater than 20,000, it becomes necessary to move towards more accurate clamping systems, such as Leitz ThermoGrip shrink tool holders with an eccentricity of 0.01mm versus CNC collet chucks. Hydraulic chucks (esp=0.03mm) offer a similar degree of concentricity, but can deflect under high cutting pressures, resulting from high feed rates, dull tools, increased material removal, etc.
Leading woodworking tool manufacturers continue to bring other advances to the industry, including vibration-dampening steel alloys for router tools and innovative diamond-tipped aluminum cutterheads for pre-mill applications (edgebanding).
Lightweight aluminum alloy tool bodies can be balanced to higher standards than their steel-bodied counterparts. The unique design also lends itself to quieter operation and improved dust flow, and the lighter mass results in “soft-jumping,” specifically for edgebanding applications.
As this article suggests, making the change from carbide or steel tools to DP is not as easy as simply changing out a bit and pressing the START button. But with precaution and forethought, diamond tooling can make a dramatic difference to your bottom line.
Brian Meier is an applications engineer for Leitz Tooling Systems Inc. For more information, call (616) 698-7010 or visit LeitzTooling.com
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