1. Field of the Invention
The present invention generally relates to techniques for manufacturing surgical instruments and, more particularly, is concerned with a belt grinding machine and method for forming cutting edges of complex geometry on surgical instruments.
2. Description of the Prior Art
Different surgical instruments, such as surgical needles, biopsy instruments and the like, have cutting edges of diverse and complex geometry formed thereon. These cutting edges need to be formed at particular angles which differ from one type of instrument to another depending on how the given instrument is used in the various surgical procedures.
One current approach to forming cutting edges on surgical needles requires the employment of two machines which use grinding wheels. Due to the limits of the grinding wheel contact surface, grinding material media and material removal rates, the tips of the needles are preliminarily ground on one machine and then passed to another machine to finish the grinding process. This is a cumbersome and time-consuming approach.
Other troublesome problems arise under the current approach. The grinding wheel traverses horizontally across the needle. The tight spacing from the needle tip of the structure supporting the needle tip limits the ability of the wheel to grind closely to the needle tip. Also, the grinding cycle time is lengthy, such as about five minutes. Further, the grinding wheel surface finish is restricted to one type of media which typically breaks down relatively fast. The wheel dressing procedure to restore the media, which is manually performed by an operator, is hazardous and time consuming, and involves a complicated grinding algorithm. Finally, as more needles are ground, the grinding wheel decreases in diameter. The feed rate must be changed accordingly to obtain a precisely finished needle.
Consequently, a need exists for a different approach to forming the cutting edges on surgical instruments, such as needles, which will overcome the aforementioned problems of the current grinding wheel technique without introducing a new set of problems in their place.