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The Secrets of Successful Pad Printing

(February 2003) posted on Wed Mar 12, 2003

This discussion expains how you can make the most of your machine by considering all aspects of production, from climate and press location to substrate readiness and ink preparation.

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By Carol Swift, Peter Kiddell

Depending on the configuration of the press, you may require two operators: one to pack and unpack the parts and the other to control printing functions. Even with the most sophisticated automated pad-printing systems, you will need somebody to keep an eye on the machine when it's in use to ensure that it's operating properly and delivering the desired print quality.


Packaging and cleanliness of components


Being able to move parts freely to and from the press is only part of the equation for efficient production. Unless these parts are immediately ready for printing, having them on hand at the press becomes meaningless. The two main concerns you have in terms of part readiness are packaging and cleanliness.

Packaging The vast majority of parts that are pad printed are made of plastic and typically arrive packed in a plastic bag that is sealed in a cardboard box. With this double packaging, removing parts for printing can create a bottleneck. Because pad printing is best carried out as a continuous process, individually unpacking and printing one component at a time can lead to a slow or erratic pace and eventually can cause print problems. However, by establishing a part-unpacking routine as a separate step prior to production, you can eliminate these problems.


The plastic bags in which parts are generally packaged lead to another concern as well. These bags are normally polypropylene or polyethylene, and separating them from the parts they contain is an excellent means of generating static on the parts. This static can have an adverse effect on the print quality, causing ink to spiderweb across the parts during printing and fail to adhere. Static also attracts dust and debris that can further diminish print quality. We'll look at this problem more closely in a following section.


Cleanliness Once you have parts unpacked, the surface condition of those parts becomes a crucial consideration. Each part must be free of contaminants that can affect ink adhesion. Contamination can be as simple as a fingerprint or leaching of plasticizers or other additives in plastic materials.



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