Examine some of the solutions on the market today.
All too often nesting fixtures are an afterthought in tooling up for a job. In pad printing, it is necessary for the part to be properly supported, especially at critical stress points and areas where the forces of pad compression are greatest. The nests also need to be ergonomically correct and where several nests are necessary, within a few thousandths of an inch of being exactly the same. In some applications, the type of pad to be used must be taken into consideration when designing the nests.
In the interest of saving time and money, it is sometimes tempting to go to the tool maker down the street to have your nests built. That is fine, provided that your tool maker has experience dealing with pad printing. On several occasions, I have seen quality problems result from a lack of pad-printing-process knowledge in the design of nests, especially on automated systems.
Pad-printing-equipment manufacturers should know how to design and build nesting fixtures correctly. Let them build your nesting fixtures, at least until you become proficient enough to be able to educate the tool maker you use.
Of course, not all parts are critical enough in nature to warrant having someone build your nests. Some parts require little more than double-sided tape or a lump of modeling clay as a nest. A lot of people make their own nests for one-up printing jobs by using automotive body filler. You can find or build a container, mix the filler, pour it into the container, then place your part in at the angle you want. (Spray the part first with a light lubricant so you can get it out of the filler after it cures.) After 30 minutes or so, the filler is cured hard enough for uneven surfaces, tight corners, and rough edges to be sanded away for a reasonable, consistent fit.
Operator safety is everyone's concern. Some pad printers don't require any safety equipment, while others require complex enclosures or light curtains. Most automatic machines come with standard safety guards or shields that are effective and don't interfere with the efficient operation of the printer.
The potential for productivity
If you can develop a way to hold a part steady and transport it, chances are good that the product is a suitable candidate for pad printing. Consider the types of jobs you currently accept, think about the types of projects you'd like to handle, and involve the equipment manufacturer in these processes. In the end, you'll come to appreciate that pad printing really is both a precise and flexible method of decorating.
About the author
John Kaverman is national sales manager for Innovative Marking Systems, Lowell, MA. He holds a degree in printing technology from Ferris State University and has more than 20 years of combined experience in the pad-printing and screen-printing industries. Kaverman welcomes comments and questions and can be reached by e-mail at email@example.com.
Editor's note: This article is an excerpt from John Kaverman's Pad Printing Technical Guidebook. You can purchase the book by visiting the ST Online Bookstore at http://www.stmediagroup.com/st-bin/quikstore.cgi or by calling 513-421-2050.
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