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Tooling and Techniques for Pad-Printing Irregular Products

(July 2006) posted on Thu Jul 06, 2006

Find out how to manipulate artwork and select the right equipment and consumables to pull off the project successfully.

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By Linda Huff

The solution is to account for the print distortion in the artwork itself. It's a trial-and-error process. The artwork must be modified to be proportional to the part once it has been printed. Using the rubber ball, for example, the artwork on the cliche should be larger in diameter to cover the surface of the ball. This type of modification requires rotating, minimizing, skewing, and even stretching the artwork, which in turn requires re-etching and re-testing each piece of artwork until the distortion is eliminated in the final print. This will give you the proper registration of the image to the part being printed.

The process is an arduous one that can take several cliches before you're ready for production. However, your suppliers have probably encountered similar projects and likely can offer quick solutions to reduce the time and number of cliches lost during this procedure.

The same considerations hold true for printing process colors and raised lettering. Both involve considerable time spent on trial-and-error testing. For multicolor prints, issues arising from artwork distortion can be compounded by registration problems. Registration of the print is sometimes confused with location. Location refers to the part, whereas registration refers to the cliche. With correct registration and location, the ink will only be transferred where you want it.

The location of the part generally can be adjusted by means of an x-y table or fixture (Figure 1); registration is corrected directly through the artwork on the cliche. Some pad-printing machines also offer the option of registration via the cliche holder. This unique feature is usually found only on multicolor pad presses. It eliminates much of the prepress setup time by allowing the operator to adjust each image during machine configuration. If your press doesn't have this feature, you'll have to adjust the artwork and etch a new cliche until the registration issues are fixed.

Equipment capability


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