| 摘要 |
A control system and method automatically control a glow discharge apparatus, as for ion nitriding, utilizing operator selected parameters (such as warm-up time, processing time, workpiece operating temperature and chamber pressure). During warm-up the control system provides a profile of the desired workpiece temperature, the desired profile temperature increasing with time at a rate that is reduced as the workpiece approaches its operating temperature. The control system compares the desired profile temperature with the measured workpiece temperature and compares the rate of change of the desired profile temperature with the rate of change of the measured workpiece temperature. It adjusts the level of electrical energy being supplied to the glow discharge in accordance with the comparison results. When the operator selected operating temperature is reached, the control system terminates the profile and operates to maintain that temperature. The control system provides a profile of increasing pressure per unit time during warm-up and operates to provide the desired pressure at any time. The control system senses an incipient arcing condition (streamer). The system sets a base energy level upon sensing the first streamer. During repeated time periods of predetermined duration the control system measures streamers both as to number and as to cumulative time occupied and operates in response thereto to control the level of supplied electrical energy.
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