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Sorting Out Squeegee Sharpeners

(December 2013) posted on Wed Dec 18, 2013


By Screen Printing's Solution Sourcebook

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Squeegee sharpeners recondition production-worn squeegee blades and make these critical, but often overlooked, tools ready to return to press. Dull edges, nicks, and uneven profiles are some of the problems that can prevent the squeegee from properly playing its vital role in transferring ink to the substrate.

Normal wear and tear from printing can lead to defects in the squeegee blade, as can exposure to inks and chemicals, mishandling, and improper storage. The squeegee sharpener is the tool that screen printers use to restore the squeegee blade’s edge so the squeegee can be brought back to action. Squeegee sharpeners are available in different sizes and configurations.

Squeegee grinders
Squeegee grinders use abrasives to remove material from the squeegee blade. The two most common types are belt and wheel grinders. Long-belt grinders are the oldest kind. They use a continuous belt that spans the length of the squeegee blade so that the entire length of the blade may be held against the belt during grinding. Wheels or pulleys drive the belt. Operators can build fixtures to hold squeegee blades at different angles. The use of such jigs enable the grinder to produce custom blade profiles and edge characteristics.

Short-belt grinders (Figure 1) also use a grinding belt and pulleys or wheels as drivers, but the squeegee is held still while the belt-driving system travels from one end of the squeegee blade to the other. The single point of contact made between the moving belt and the squeegee blade’s surface puts less pressure on the squeegee, which means a reduction in blade deformation during grinding. Edge straightness and uniformity of height also improve when the holding device and wheel movement are held parallel.

Heat generation, tearing, and material buildup are among the challenges associated with belt grinders. Friction creates heat, and pressure causes deflection. A tearing effect causes little peaks and valleys on the edge of the squeegee blade. Those peaks will break off, and the valleys tend to cause streaks in the prints. Ground urethane can become lodged in the abrasives embedded in the grinding belt. When enough squeegee material builds up on the belt, the machine may grind erratically or ineffectively.

