Identify the primary types of sharpening systems and learn about the features and functions available on these devices.
Diamond wheels are the most common types found in wheel-based sharpeners. They can be manufactured to produce a variety of blade profiles (Figure 3). Diamond wheels are designed to wear at a slower rate than stones, but both should be routinely checked for proper alignment. As is the case with long- and short-belt machines, the belt-wrapped wheel can generate excessive heat and lose efficiency as blade materials build up on the belt.
Manufacturers have added features and functions to their squeegee grinders in order to deal with temperature management, debris removal, and squeegee-blade handling. Cooled pulleys and tooling or machine components designed to naturally dissipate heat are some of the tactics used to prevent temperatures from climbing too high. Vacuum systems are integrated in some units to help remove urethane dust and particulates and prevent them from clogging the grinding media. In some cases, the operator need only attach a vacuum cleaner to a port (Figure 4). Finally, mechanical and pneumatic clamps are used to hold the squeegee blade steady during grinding, thereby further ensuring the production of a straight edge and uniform height.
Squeegee cutters use knives, either stationary or rotating, to remove material. Some machines heat the knives to aid the cutting process. Rogers says these knives are heated to 120-130°F, a bit more than half as hot as the melting point of the squeegee-blade material.
"It'll never melt the blade whatsoever," he says. "If you're trying to cut a stick of butter and you run a knife under hot water, then it's easier to cut the butter than if the knife were cold. It lowers the cutting resistance."
Cold-knife machines may come standard with cooling/lubricating systems to aid the cutting process and prevent heat buildup from occurring (Figure 5). Some squeegee cutters use knives that can be bought at hardware and grocery stores, such as box-knife blades and injector-style razor blades. Other units require the use of proprietary blade systems. Either way, these machines can remove squeegee-blade material while generating minimal amounts of debris. That attribute makes squeegee cutters popular in industrial and specialty screen-printing operations in which production must be confined to a clean room.
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