Edm process a method and apparatus for controlling the flow rate of dielectric as a function of gap impedance

Claim 1

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said machining gap being supplied machining pulses from a power supply for generating electrical discharges thereacross, the apparatus comprising: a. means in fluidic communication with the machining gAp for supplying a flowrate of dielectric thereto; b. means connected across the machining gap for detecting changes in electrical impedance in said gap only during time periods between the machining pulses; and c. means connected between the detecting means and the supplying means for controlling the flow rate of dielectric through the gap as a function of the detected changes in electrical impedance.

Claim 2

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said machining gap being supplied machining pulses from a power supply for generating electrical discharges thereacross, the apparatus comprising: a. means in fluidic communication with the machining gAp for supplying a flowrate of dielectric thereto; b. means connected across the machining gap for detecting changes in electrical impedance in said gap only during time periods between the machining pulses; and c. means connected between the detecting means and the supplying means for controlling the flow rate of dielectric through the gap as a function of the detected changes in electrical impedance.

Claim 3

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said machining gap being supplied machining pulses from a power supply for generating electrical discharges thereacross, the apparatus comprising: a. means in fluidic communication with the machining gap for supplying thereto a flow rate of dielectric varying in predetermined quantitative increments; b. means connected across the machining gap for detecting predetermined magnitudes of electrical impedance in said gap only during time periods between the applied machining pulses; and c. means connected between the detecting means and the supplying means for changing the flow rate by the quantitative increments in response to the detected predetermined magnitudes of electrical impedance.

Claim 4

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said machining gap being supplied machining pulses from a power supply for generating electrical discharges thereacross, the apparatus comprising: a. means in fluidic communication with the machining gap for supplying thereto a flow rate of dielectric varying in predetermined quantitative increments; b. means connected across the machining gap for detecting predetermined magnitudes of electrical impedance in said gap only during time periods between the applied machining pulses; and c. means connected between the detecting means and the supplying means for changing the flow rate by the quantitative increments in response to the detected predetermined magnitudes of electrical impedance.

Claim 5

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said gap being supplied machining pulses from a machining power supply for generating electrical discharges thereacross, the apparatus comprising: a. a dielectric reservoir; b. a pumping apparatus connected to the reservoir and in fluidic communication with the machining gap for generating a flow rate of dielectric through the machining gap; c. means coupled to the machining power supply for producing a signal during time periods between the electrical discharges; d. means having inputs connected across the machining gap and responsive to the signal for detecting electrical impedance changes in the machining gap only during the time periods between the electrical discharges; and e. a flow rate control having an input connected to the detecting means and an output connected to the pumping apparatus for controlling the generation of flow rate through the machining gap as a function of the detected changes in electrical impedance.

Claim 6

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said gap being supplied machining pulses from a machining power supply for generating electrical discharges thereacross, the apparatus comprising: a. a dielectric reservoir; b. a pumping apparatus connected to the reservoir and in fluidic communication with the machining gap for generating a flow rate of dielectric through the machining gap; c. means coupled to the machining power supply for producing a signal during time periods between the electrical discharges; d. means having inputs connected across the machining gap and responsive to the signal for detecting electrical impedance changes in the machining gap only during the time periods between the electrical discharges; and e. a flow rate control having an input connected to the detecting means and an output connected to the pumping apparatus for controlling the generation of flow rate through the machining gap as a function of the detected changes in electrical impedance.

Claim 7

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said gap being supplied machining pulses from a machining power supply for generating electrical discharges thereacross the apparatus comprising: a. a dielectric reservoir; b. a pump connected to the reservoir and producing a flow rate of dielectric; c. valving apparatus connected to the pump and in fluidic communication with the machining gap for controlling the flow rate of dielectric through the gap; d. means coupled to the machining power supply for producing a signal during time periods between the machining pulses; e. means having inputs connected across the gap and responsive to the signal for detecting electrical impedance changes in the gap during the time periods between machining pulses; and f. a control device having an input connected to the detecting means and an output connected to the valving apparatus for varying the flow rate of dielectric through the machining gap as a function of the detected changes in electrical impedance.

Claim 8

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said gap being supplied machining pulses from a machining power supply for generating electrical discharges thereacross the apparatus comprising: a. a dielectric reservoir; b. a pump connected to the reservoir and producing a flow rate of dielectric; c. valving apparatus connected to the pump and in fluidic communication with the machining gap for controlling the flow rate of dielectric through the gap; d. means coupled to the machining power supply for producing a signal during time periods between the machining pulses; e. means having inputs connected across the gap and responsive to the signal for detecting electrical impedance changes in the gap during the time periods between machining pulses; and f. a control device having an input connected to the detecting means and an output connected to the valving apparatus for varying the flow rate of dielectric through the machining gap as a function of the detected changes in electrical impedance.

Claim 9

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said gap being supplied machining pulses from a machining pOwer supply for generating electrical discharges thereacross, the apparatus comprising: a. a variable dielectric supply in fluidic communication with the machining gap for generating a flow rate of dielectric through the gap in a predetermined number of quantitative increments; b. a direct current power supply coupled to the machining power supply for producing a direct current signal during time periods between machining pulses; c. an impedance bridge having the machining gap connected in one leg thereof and being responsive to the direct current signal for measuring predetermined incremental changes in electrical impedance in the machining gap; and d. a control device connected to the impedance bridge and the dielectric supply for changing the flow rate in predetermined quantitative increments as a function of the incremental changes in electrical impedance.

Claim 10

An apparatus for use in an EDM process for controlling a flow rate of dielectric through a machining gap formed in a dielectric medium between an electrically conductive tool and an electrically conductive workpiece, said gap being supplied machining pulses from a machining pOwer supply for generating electrical discharges thereacross, the apparatus comprising: a. a variable dielectric supply in fluidic communication with the machining gap for generating a flow rate of dielectric through the gap in a predetermined number of quantitative increments; b. a direct current power supply coupled to the machining power supply for producing a direct current signal during time periods between machining pulses; c. an impedance bridge having the machining gap connected in one leg thereof and being responsive to the direct current signal for measuring predetermined incremental changes in electrical impedance in the machining gap; and d. a control device connected to the impedance bridge and the dielectric supply for changing the flow rate in predetermined quantitative increments as a function of the incremental changes in electrical impedance.

Claim 11

A method for use in an EDM process for automatically controlling a flow rate of dielectric through a machining gap having electrical machining pulses applied thereto for producing electrical discharges thereacross, the method comprising the steps of: a. generating a flow rate of dielectric through the machining gap; b. detecting changes in electrical impedance in the machining gap only during time periods between the applied machining pulses; and c. controlling automatically the generation of flow rate of dielectric as a function of the changes detected in the electrical impedance.

Claim 12

A method for use in an EDM process for automatically controlling a flow rate of dielectric through a machining gap having electrical machining pulses applied thereto for producing electrical discharges thereacross, the method comprising the steps of: a. generating a flow rate of dielectric through the machining gap; b. detecting changes in electrical impedance in the machining gap only during time periods between the applied machining pulses; and c. controlling automatically the generation of flow rate of dielectric as a function of the changes detected in the electrical impedance.

Claim 13

A method for use in an EDM process for controlling a flow rate of dielectric through a machining gap having electrical machining pulses applied thereto for producing electrical discharges thereacross, the method comprising the steps of: a. generating a flow rate of dielectric through the machining gap; b. detecting predetermined increments of electrical impedance magnitudes in the machining gap only during time periods between the applied machining pulses; and c. changing the generation of flow rate in quantitative increments as a function of the detected increments of impedance magnitudes.

Claim 14

A method for use in an EDM process for controlling a flow rate of dielectric through a machining gap having electrical machining pulses applied thereto for producing electrical discharges thereacross, the method comprising the steps of: a. generating a flow rate of dielectric through the machining gap; b. detecting predetermined increments of electrical impedance magnitudes in the machining gap only during time periods between the applied machining pulses; and c. changing the generation of flow rate in quantitative increments as a function of the detected increments of impedance magnitudes.