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Accessories for Automating Multicolor Pad Printing

(July 2008) posted on Wed Jul 16, 2008

Automation can improve the quality, consistency, and productivity with high-volume, multicolor pad-printing jobs. This article explores parts-handling devices and other accessories that can improve accuracy and efficiency in your shop.


By Christopher Connell

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Keep in mind that not all process-color jobs can be directly printed on any shade of material. Substrates that are colored or transparent may require an undercoat or a background of white to allow the semitransparent cyan, magenta, and yellow inks to properly reflect their true colors. Thus, the job necessarily may become a five-color project with white and black finishing the look.

Many multicolor jobs don’t involve traditional process-color printing. Instead, they may have several spot colors or even many layers of artwork. For example, the high-gloss finishes that you see on electronics and cell phones are frequently created by applying multiple layers of metallic inks with a final clear coat. You can also apply several custom-matched spot colors at widely spaced intervals by using multiple inkcups and special pad assemblies.

With large, multicolor applications, it’s possible to break an image in to smaller parts. By carefully dissecting large artwork into segments, each piece of the whole image can then be inked by a separate cup and, in turn, reassembled into the complete image during printing.

Multicolor pad-printing comes with its own set of challenges and difficulties. The correct formulations of inks and thinners—always important in single-color jobs—become even more critical with two or more colors. When in doubt, read and follow the ink manufacturers’ instructions printed on the containers. You should also monitor and control ambient air conditions to ensure consistency from start to finish. And don’t forget your pad blowers—they speed up multicolor jobs by helping ink transfer and release properly. They also flash off the solvents, thereby allowing your operation to run at peak rate.

Effective curing and part handling are especially important when so much ink is transferred to a part. A good rule of thumb is to apply moderate heat for as long possible without damaging the part. Though the ink on a recently printed part may feel dry to the touch, it isn’t truly cured for 48 hours—unless forced heat is used.

 

The added value of expertise

Before leaping into automated pad printing, first weigh the costs of trial-and-error guesswork or calling an expert. Buying any product without ongoing support is a simple, one-time business transaction. You pay your money and take delivery on the item. It’s like buying a hammer at the hardware store. Support beyond the sale is not included, so you’re on your own.


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