For those fine details found in high-quality production runs, especially on automatic presses, not only must your squeegee edge be sharp, but also free of nicks, waves, and varying blade height. A tiny smidgen nicked out of a straight edge can translate into nasty streaks, especially noticeable in large areas of a single-color design printed with transparent inks. Waves in the printing edge might be due to compression of the holder screws, swelling from chemical action, or incorrect squeegee storage. If the blade height is not uniform across the screen, you might find one side or corner of your print is out of registration. Maladjusting the platen level to compensate for the poor printing might even ruin a well-designed automatic press.
Many printers use an abrader wheel for softer durometer squeegees.
An automated machine with a special blade-holding device is also available. One distortion that sharpeners cannot correct is lateral warping or meandering of the blade from left to right. Such twisting is probably due to improper care of the tool. Squeegee length should fit the image being printed. Choose a blade that extends about 1 in.