Answers to frequently-asked questions
Squeegee manufacturers, in pursuit of a you-can-have-it-all squeegee, have captured part of the market with alternatives to the single-durometer squeegee.
A multidurometer squeegee offers two durometers on the same blade and is available in two styles. The first is the front-back dual-durometer squeegee (for example, a 60/90 combination). One disadvantage of this style is that it offers only one printing edge and must be rested after sustained use. Pulled in only one direction, it tends to bow out. The harder back of the blade is also less permeable to solvents and tends to swell less than the lower-durometer printing layer.
The triple-durometer blade (for example, a 70/90/70 combination) was a natural step in the evolution of the squeegee. In our example, by laminating softer polyurethane on both sides of the 90-durometer material, the printer has two working edges and can avoid the bowing and warping problems of the dual-durometer squeegee.
Another answer to the must-be-stiff-to-avoid-roll-over-but-soft-to-follow-the-substrate question is to modify the blade holder. For example, the Indexable Squeegee®, from Printer's Edge, Warren, OH, has a squeegee holder that reduces the unsupported blade height, and thus maintains the rigidity of the squeegee (which can be a soft 60, or even 50, durometer). The blade is then advanced from the holder as needed, somewhat similar to the action of a mechanical pencil.
Yet another answer is to back a soft squeegee blade with a metal support. For example, the Flex-Control adjustable blade brace mounts a dialable plate behind the squeegee. Also manufactured by Printer's Edge, the device allows consistent control of the support of the squeegee.
One caveat: Durometers change depending on time and usage. At the end of an 8-hr press run, the ink chemicals will have permeated and softened the polyurethane. At 9:00 am it's a 70-durometer squeegee and by 6:00 pm it's softened to 65--and you wonder why the ink is laying down thicker and thicker? No problem. Just change the squeegee during your noontime break. However, over the longer term, your squeegees will harden. Through the months, the constant absorption and release of ink chemicals will interfere with the elasticity of the squeegee.
Which Squeegee Profile Works Best?
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