Constant current needle annealing device and a method of producing an annealed needle

摘要

A constant current annealing device for annealing a wire or surgical needle is disclosed. The device includes amplitude and time setting devices, such as thumb-wheel switches. A constant current source is connected to the current setting device. The constant current source is switchable, through a switch for example, in response to a timing signal to provide a constant current for a predetermined duration. A pair of spaced apart electrodes are clamped on the needle and a switching device is connected between the constant current source and the pair of electrodes. The voltage drop across the switching device varies to compensate for load variations, thus keeping the anneal current constant in the anneal ON mode. In the anneal OFF mode, where current is not provided to the needle, the switching device shunts a residual current away from the electrodes. The time setting device include a programmable logic controller (PLC) and a solid state relay to provide an accurate timing signal. A current measuring and monitoring device is connected to another PLC, which shuts down the annealing device after a predetermine number of alarms or after the constant current amplitude deviates by a predetermined amount.