The conventional screw and rivet header uses a die and two punches to cold form the finished cold headed blank. Visitors going for a plant tour often are amazed to watch single die-two blow header cranking out cross recess screw blanks at rates of around three parts a second. A typical comment is "So that's how you do that." In one way, they are correct in thinking they have just seen how screw blanks are formed. However, they are also not seeing a large part of the actual forming processes sinceit all happens so quickly. In a way, it is kind of like magic, in that the viewer really misses something that is actually happening right in front of them when their attention is diverted. While the finished blank draws one's attention during operation,it is the intermediate step of the first blow punch that is pivotal to the quality of the final blank. This preform controls much of the entire process and holds the potential to produce a quality part or make a lot of people very unhappy. Let's considerthe blank in Figure 1, which will be used in a popular outdoor recreation product.
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