Electric heating – Metal heating – Cutting or disintegrating
Patent
1992-05-05
1995-04-18
Evans, Geoffrey S.
Electric heating
Metal heating
Cutting or disintegrating
219 6913, 323283, 36447404, B23H 720
Patent
active
054080649
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF INVENTION
Field of the Invention
This invention generally relates to an apparatus and method of generating electrical pulses and, more particularly, to an apparatus and method of generating electrical machining pulses in the power supply of an electric discharge machining (EDM) system.
Description of Prior Art
In conventional power supply units for EDM systems pulses of electrical power are supplied to a workpiece; the pulses having preset on-times and off-times. The power supply unit then supplies a train of pulses based upon the pre-set on-time and the pre-set off-time.
An example of the conventional power supply unit is shown in FIG. 10(A). The unit includes pulse generator 100 having a counter 101 for counting ON time clock pulses applied to its input. The output of the counter 101 goes to a comparator 102 which compares the count from counter 101 to a number stored for ON time data comparator 102. The ON time data specifies the time during which the pulses are at a high level, or "on." When the count from the counter 101 equals the number stored for ON time data, the comparator 102 sends a signal to reset a RS flip-flop 105.
The pulse generator 100 also includes a counter 103 for counting the number of OFF time clock pulses applied to its input. A comparator 104 receives the count from counter 103 and compares it to a number stored for OFF time data, which specifies the time period between pulses. When the count from the counter 102 equals the number stored for OFF time data, the comparator 104 sets the RS flip-flop 105.
The output of the RS flip-flop also resets the counters 101 and 103. The output of the RS flip-flop 105 is connected to the enable input of the counter 101 and to the enable input of counter 103 through an inverter 106. Thus, when the output of RS flip-flop goes high, the on-time counter is enabled to count on-time clock pulses and when the output of the RS flip-flop 105 goes low, the off-time counter is enabled to count off-time clock pulses.
By the setting and resetting of the RS flip-flop 105, a plurality of pulses are generated at its output. While the level of each pulse is high, the counter 101 counts the ON time clock pulses until the count reaches the count stored for the ON time data, at which time counter 101 stops counting and resets the RS flip-flop 105. Counter 103 is then enabled to count the OFF time clock pulses. Counter 103 counts up to the number stored for the OFF time data, at which time counter 103 stops counting and RS flip-flop 105 becomes set. Counter 101 is then enabled and the process repeats itself.
FIG. 10(B) illustrates the use of the pulse generator in an electric discharge machining apparatus. As shown in the figure, a divider 111 supplies the counter 101 with ON time clock pulses and a divider 112 supplies the counter 103 with OFF time clock pulses. A CPU supplies comparator 102 and comparator 104 with ON time data and OFF time data, respectively. The dividers 111 and 112 divide the clock pulses according to data, for example a voltage signal, detected at a gap G formed between an electrode E and a workpiece W.
FIG. 10(C) illustrates a conventional pulse generator 300 in which only the off-time is controlled. The pulse generator 300 has a ROM 301 located between the CPU and the comparator 102 and a ROM 302 located between the CPU and the comparator 104. The ROMs 301 and 302 supply ON time data and the OFF time data to the comparators 102 and 104, respectively, based upon the initial values stored in memory. A divider 303 receives a clock signal and supplies an output divided according to detected data from the gap G to the off-time counter 103.
In conventional pulse generators of the type illustrated in FIGS. 10(A) to 10(C), however, the data to be selected for evaluation and analysis is implemented in a dedicated circuit. The manner in which this data is to evaluated and analyzed for the control of ON time data and OFF time data is also implemented in a dedicated circuit. Thus, in the prior art circuits it is difficult to modify th
REFERENCES:
patent: 3705286 (1972-12-01), Kondo et al.
patent: 4071729 (1978-01-01), Bell, Jr.
patent: 4128771 (1978-12-01), Domonico
patent: 4320279 (1982-03-01), Bell, Jr. et al.
patent: 4356542 (1982-10-01), Bruckner et al.
patent: 4361745 (1982-11-01), Rupert et al.
patent: 4370536 (1983-01-01), Kruth
patent: 4392043 (1983-07-01), Inoue
patent: 4673791 (1987-06-01), Kenno et al.
patent: 4800248 (1989-01-01), Futamura et al.
patent: 4920246 (1990-04-01), Aoki
patent: 5149940 (1992-09-01), Davis et al.
patent: 5182474 (1993-01-01), Kaneko
patent: 5233158 (1993-08-01), Karakama et al.
patent: 5254937 (1993-10-01), Mizoguchi
Translation of Japan, Kokai, 59-169,717 by Otayaki et al., PTO 94-2634.
Evans Geoffrey S.
Sodick Co. Ltd.
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