This invention is directed to an apparatus for forming the leads of an electrical component. More particularly, this invention involves a lead forming device which is capable of automatically accommodating a variety of component and lead geometries, and for automatically compensating for variations between consecutive parts of the same type.
Many electronic components, such as integrated circuits, have a component body with a plurality of leads extending outward from the body for connection to a printed circuit board. To facilitate surface mounting and connecting such components, the leads are often formed by being bent and trimmed to a specific configuration. Prior art devices for forming leads utilize dedicated dies. Each part size, form shape and form dimension requires a unique die set. Die sets can be very costly and they consume valuable work space. When a die is initially manufactured, the final configuration of the part is not precisely known until the die is tested. Unknowns and tolerances in dimensions, die spring constants, number of die springs, and die actuation forces can affect the final product form. It is not uncommon for dies to be reworked several times before the desired form is created. For any program that requires more than a few die sets, the cost and required work space can become prohibitive. In a development laboratory environment, where a large variety of different electronic components are handled on a low volume basis, prior art devices are particularly inadequate.
In addition to variations between types of components and desired lead geometries, there are variations on a part-to-part basis for which prior art devices do not adequately compensate. For example, variations in lead exit height and lead thickness can cause a formed component to exceed the allowable variation in standoff height, which is a critical dimension affecting both mounting integrity and heat dissipation. Prior art devices provide little flexibility in adjusting the forming die or forming process to compensate for such variables.