TWI839191B - Wire EDM Processing - Google Patents

Abstract

A wire cutting discharge machining method is applied to a discharge machining device to perform discharge machining on a workpiece. The wire cutting discharge machining method comprises the following steps: (A) a control unit of the discharge machining device controls a first transistor to switch from a first open circuit state to a first passage state, thereby establishing an ignition discharge channel; (B) the control unit controls the first transistor to switch from the first passage state back to the first open circuit state, and controls a second transistor to switch from a second open circuit state to a second passage state, so as to perform discharge machining on the workpiece through the ignition discharge channel; and (C) the control unit outputs a pulse signal to the second transistor, so that the wire electrode unit partially melts and is coated on the workpiece, thereby preventing the workpiece from pressing the wire electrode unit due to separation and deformation due to discharge machining, thereby ensuring stable operation of the overall steps.

Description

Wire EDM Processing

The present invention relates to a processing method, in particular to a wire cutting discharge processing method.

Currently, existing wire-cut EDM equipment can perform EDM on a workpiece to partially melt the workpiece and then cut out a predetermined contour.

However, when the existing wire-cut EDM device performs EDM on the workpiece through a wire electrode unit, the waste material cut from the workpiece is prone to tilt or shift and press against the wire electrode unit, thereby causing the wire electrode unit to break. Obviously, the existing wire-cut EDM device and its control method still have room for improvement.

Therefore, the purpose of the present invention is to provide a wire cutting discharge machining method that can overcome the above-mentioned shortcomings.

Therefore, the wire cutting discharge processing method of the present invention is applied to a discharge processing device, which is suitable for performing discharge processing on a workpiece and includes a workbench for placing the workpiece, a wire electrode unit corresponding to the position of the workbench, a low-voltage ignition unit connected in series between the workbench and the wire electrode unit, and a low-voltage ignition unit connected in series between the workbench and the wire electrode unit and in parallel with the low-voltage ignition unit. The high-voltage discharge unit of the element and a control unit are provided. The low-voltage ignition unit has a first transistor, a current-limiting resistor and a low-voltage power supply connected in series between the workbench and the electrode unit. The high-voltage discharge unit has a second transistor and a high-voltage power supply connected in series between the workbench and the electrode unit. The control unit is electrically connected to the first transistor and the second transistor. The wire cutting discharge processing method includes: The following steps are as follows: (A) the control unit controls the first transistor to switch from a first open circuit state to a first open circuit state, thereby driving the low voltage power supply to establish an ignition discharge channel between the workbench and the electrode unit; (B) the control unit controls the first transistor to switch from the first open circuit state back to the first open circuit state, and controls the second transistor to switch from a second open circuit state to a second open circuit state. (C) the control unit outputs a pulse signal of a pulse duration to the second transistor according to a predetermined cycle to control the second transistor to switch between the second open circuit state and the second open circuit state, thereby partially melting the electrode unit and applying the melted portion of the electrode unit to the workpiece.

The effect of the present invention is that the control unit controls the first transistor to establish the ignition discharge channel, and the control unit controls the second transistor to perform discharge processing on the workpiece through the ignition discharge channel, and then the control unit outputs the pulse signal to the second transistor to partially melt the electrode unit and apply it to the workpiece, so as to prevent the workpiece from being separated and deformed due to discharge processing and pressing the electrode unit, thereby ensuring the stable operation of the overall step.

100: Discharge processing equipment

1: Workbench

2: Linear electrode unit

3: Low-voltage ignition unit

31: First transistor

32: Current limiting resistor

33: Low voltage power supply

4: High voltage discharge unit

41: Second transistor

42: High voltage power supply

5: Control unit

9: Workpiece

S11~S13, S21~S24, S31~S34: Steps

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: FIG. 1 is a circuit diagram of a discharge machining device and a workpiece applied to a first embodiment of the wire cutting discharge machining method of the present invention; FIG. 2 is a flow chart of the first embodiment; FIG. 3 is a waveform diagram illustrating the correspondence between a gap voltage, a control signal received by a first transistor, a control signal received by a second transistor, and a discharge current of the first embodiment; FIG. 4 is a flow chart illustrating the wire cutting discharge machining method of the present invention. FIG. 5 is a waveform diagram illustrating the corresponding relationship between the gap voltage, the control signal received by the first transistor, the control signal received by the second transistor, and the discharge current of the second embodiment; FIG. 6 is a flow chart illustrating a third embodiment of the wire cutting discharge machining method of the present invention; and FIG. 7 is a waveform diagram illustrating the corresponding relationship between the gap voltage, the control signal received by the first transistor, the control signal received by the second transistor, and the discharge current of the third embodiment.

Referring to FIG. 1 and FIG. 2 , a first embodiment of the wire cutting discharge machining method of the present invention is applied to a discharge machining device 100, which is suitable for performing discharge machining on a workpiece 9 and includes a workbench 1 for placing the workpiece 9, a wire electrode unit 2 whose position corresponds to the workbench 1 and is continuously fed, a low-voltage ignition unit 3 connected in series between the workbench 1 and the wire electrode unit 2, a high-voltage discharge unit 4 connected in series between the workbench 1 and the wire electrode unit 2 and in parallel with the low-voltage ignition unit 3, and a control unit 5.

The low-voltage ignition unit 3 has a first transistor 31, a current-limiting resistor 32 and a low-voltage power supply 33 connected in series between the workbench 1 and the line unit 2. In this embodiment, the first transistor 31 is a bipolar transistor, and the low-voltage power supply 33 is used to provide a low voltage between 25 volts and 50 volts.

The high-voltage discharge unit 4 has a second transistor 41 and a high-voltage power source 42 connected in series between the workbench 1 and the line unit 2. In this embodiment, the second transistor 41 is a bipolar transistor, and the high-voltage power source 42 is used to provide a high voltage between 150 volts and 300 volts.

The control unit 5 is electrically connected to the first transistor 31 and the second transistor 41, and is used to send a control signal to the first transistor 31 and the second transistor 41 to control the first transistor 31 to switch between a first open circuit state and a first open circuit state, and to control the second transistor 41 to switch between a second open circuit state and a second open circuit state.

Specifically, the control unit 5 can be implemented by a complex programmable logic device (CPLD), a programmable array logic (PAL) or a field programmable gate array (FPGA).

Referring to Figures 1, 2 and 3, it is worth mentioning that Figure 3 shows one of the ignition discharge cycles of the first embodiment, and the first embodiment includes the following steps:

In step S11, the control unit 5 controls the first transistor 31 to switch from the first disconnected state to the first open state, and adjusts the distance between the workpiece 9 and the electrode unit 2 to a discharge gap, thereby driving the low-voltage power supply 33 to establish an ignition discharge channel between the workbench 1 and the electrode unit 2. At this time, the degree of detachment of the electric field particles between the workpiece 9 and the electrode unit 2 will rapidly intensify, causing a corresponding gap voltage between the electrode unit 2 and the workpiece 9 to drop rapidly, that is, the ignition discharge channel is successfully established.

In step S12, the control unit 5 controls the first transistor 31 to switch from the first on-state to the first off-state, and controls the second transistor 41 to switch from the second off-state to the second on-state, driving the high-voltage power supply 42 to generate a discharge spark through the ignition discharge channel within a short discharge time, so as to perform discharge processing on the workpiece 9 and generate a discharge current corresponding to the electrode unit 2 and the workpiece 9. After the discharge time is over, the control unit 5 controls the second transistor 41 to switch from the first on-state to the second off-state.

Step S13, at this time, the ignition discharge channel has not disappeared, and the control unit 5 continuously outputs a pulse signal with a pulse time △t to the second transistor 41 according to a predetermined cycle to control the second transistor 41 to switch between the second open circuit state and the second open circuit state, and drives the high voltage power supply 42 to perform arc discharge on the workpiece 9 through the ignition discharge channel. In the current step, the pulse time △t is between 5 microseconds (μs) and 1 millisecond (ms), and the discharge current is between 2 amperes and 8 amperes.

At this time, the discharge processing device 100 no longer needs to process the workpiece 9, and only needs to maintain the arc discharge between the electrode unit 2 and the workpiece 9 until the electrode unit 2 is partially melted and the melted portion of the electrode unit 2 is applied to the surface of the workpiece 9. Then, the control unit 5 controls the second transistor 41 to switch to the second open circuit state, and one of the ignition discharge cycles is declared over, waiting to enter the next ignition discharge cycle.

Through the above steps, the melted part of the electrode unit 2 is coated on the surface of the workpiece 9, achieving the effect of temporary fixation by local welding, which can prevent the workpiece 9 from pressing the electrode unit 2 due to separation and deformation during discharge machining. Moreover, since the melted part of the electrode unit 2 is only coated on the surface of the workpiece 9, the waste material cut from the workpiece 9 can be removed by knocking the workpiece 9 after machining.

Referring to Figures 1, 4 and 5, a second embodiment of the wire cutting discharge machining method of the present invention is also applied to the discharge machining device 100 used in the first embodiment. Figure 5 shows one of the ignition discharge cycles of the second embodiment. The second embodiment includes the following steps:

In step S21, the control unit 5 controls the first transistor 31 to switch from the first disconnected state to the first open state, and adjusts the distance between the workpiece 9 and the electrode unit 2 to the discharge gap, thereby driving the low-voltage power supply 33 to establish the ignition discharge channel between the workbench 1 and the electrode unit 2. At this time, the degree of detachment of the electric field particles between the workpiece 9 and the electrode unit 2 will rapidly increase, causing the gap voltage to drop rapidly, that is, the ignition discharge channel is successfully established.

In step S22, the control unit 5 controls the first transistor 31 to switch from the first pass state back to the first open state, and controls the second transistor 41 to switch from the second open state to the second pass state, driving the high voltage power supply 42 to generate discharge sparks through the ignition discharge channel within the discharge time, so as to perform discharge processing on the workpiece 9 and generate the discharge current. After the discharge time is over, the control unit 5 controls the second transistor 41 to switch from the first pass state back to the second open state.

In step S23, the control unit 5 stores a voltage threshold value and is used to detect the gap voltage between the corresponding electrode unit 2 and the workpiece 9. In this embodiment, the voltage threshold value is substantially 30 volts. The control unit 5 compares the voltage value of the gap voltage with the voltage threshold value. If the voltage value of the gap voltage is greater than the voltage threshold value, the voltage value of the gap voltage is compared with the voltage threshold value after a voltage buffer time; if the voltage value of the gap voltage is less than the voltage threshold value, the next step is continued.

Step S24, at this time, the ignition discharge channel has not disappeared, and the control unit 5 continues to output the pulse signal to the second transistor 41 to control the second transistor 41 to switch between the second disconnection state and the second passage state, driving the high-voltage power supply 42 to perform arc discharge on the workpiece 9 through the ignition discharge channel. In the current step, the pulse time △t is between 5 microseconds (μs) and 1 millisecond (ms), and the discharge current is between 2 amperes and 8 amperes.

At this time, the discharge processing device 100 no longer needs to process the workpiece 9, and only needs to maintain the arc discharge between the electrode unit 2 and the workpiece 9 until the electrode unit 2 is partially melted and the melted portion of the electrode unit 2 is applied to the surface of the workpiece 9. Then, the control unit 5 controls the second transistor 41 to switch to the second open circuit state, and one of the ignition discharge cycles is declared over, waiting to enter the next ignition discharge cycle.

Referring to Figures 1, 6 and 7, a third embodiment of the wire cutting discharge machining method of the present invention is also applied to the discharge machining device 100 used in the first embodiment. Figure 7 shows one of the ignition discharge cycles of the third embodiment. The third embodiment includes the following steps:

In step S31, the control unit 5 controls the first transistor 31 to switch from the first disconnected state to the first open state, and adjusts the distance between the workpiece 9 and the electrode unit 2 to the discharge gap, thereby driving the low-voltage power supply 33 to establish the ignition discharge channel between the workbench 1 and the electrode unit 2. At this time, the degree of detachment of the electric field particles between the workpiece 9 and the electrode unit 2 will rapidly increase, causing the gap voltage to drop rapidly, that is, the ignition discharge channel is successfully established.

In step S32, the control unit 5 controls the first transistor 31 to switch from the first pass state back to the first disconnect state, and controls the second transistor 41 to switch from the second disconnect state to the second pass state, driving the high-voltage power supply 42 to generate a discharge spark through the ignition discharge channel within a short discharge time to perform discharge processing on the workpiece 9, and generate a discharge current corresponding to the electrode unit 2 and the workpiece 9. After the discharge time is over, the control unit 5 controls the second transistor 41 to switch from the first pass state back to the second disconnect state.

In step S33, the control unit 5 stores a current threshold value and is used to detect the discharge current between the electrode unit 2 and the workpiece 9. In this embodiment, the current threshold value is 5 amperes. The control unit 5 compares the current value of the discharge current with the current threshold value. If the current value of the discharge current is greater than the current threshold value, the control unit 5 compares the current value of the discharge current with the current threshold value after a current buffer time; if the current value of the discharge current is less than the current threshold value, the next step is continued.

Step S34, at this time, the ignition discharge channel has not disappeared, and the control unit 5 continues to output the pulse signal to the second transistor 41 to control the second transistor 41 to switch between the second disconnection state and the second passage state, and drive the high-voltage power supply 42 to perform arc discharge on the workpiece 9 through the ignition discharge channel. In the current step, the pulse time △t is between 5 microseconds (μs) and 1 millisecond (ms), and the discharge current is between 2 amperes and 8 amperes.

At this time, the discharge processing device 100 no longer needs to process the workpiece 9, and only needs to maintain the arc discharge between the electrode unit 2 and the workpiece 9 until the electrode unit 2 is partially melted and the melted portion of the electrode unit 2 is applied to the surface of the workpiece 9. Then, the control unit 5 controls the second transistor 41 to switch to the second open circuit state, and one of the ignition discharge cycles is declared over, waiting to enter the next ignition discharge cycle.

Therefore, the wire cutting discharge machining method of the present invention can produce the following effects through the above steps:

(i) The control unit 5 controls the first transistor 31 to establish the ignition discharge channel, and the control unit 5 controls the second transistor 41 to perform discharge processing on the workpiece 9 through the ignition discharge channel, and then the control unit 5 outputs the pulse signal to the second transistor 41, so that the electrode unit 2 is partially melted and applied to the workpiece 9, so as to prevent the workpiece 9 from being separated and deformed due to the discharge processing and pressing the electrode unit 2, thereby ensuring the stable operation of the overall step, without arranging extra manpower and working hours to eliminate the above problems, thereby achieving the effect of saving manpower and working hours.

(ii) In the second embodiment, the control unit 5 detects the gap voltage corresponding to the electrode unit 2 and the workpiece 9 to determine whether it is necessary to supplement the pulse signal to the second transistor 41 to maintain the arc discharge between the electrode unit 2 and the workpiece 9, so that the electrode unit 2 is partially melted and coated on the workpiece 9, which is beneficial to the subsequent process application.

(III) In the third embodiment, the control unit 5 detects the discharge current between the electrode unit 2 and the workpiece 9 to determine whether it is necessary to supplement the pulse signal to the second transistor 41 to maintain the arc discharge between the electrode unit 2 and the workpiece 9, so that the electrode unit 2 is partially melted and coated on the workpiece 9, which is beneficial to the subsequent process application.

In summary, the wire cutting discharge machining method of the present invention solves the problem that the electrode unit 2 is easily broken by the workpiece 9 through simple steps, and can indeed achieve the purpose of the present invention.

However, the above is only an example of the implementation of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

S11~S13: Steps

Claims (2)

A wire cutting discharge processing method is applied to a discharge processing device, which is suitable for performing discharge processing on a workpiece and includes a workbench for placing the workpiece, a wire electrode unit corresponding to the position of the workbench, a low-voltage ignition unit connected in series between the workbench and the wire electrode unit, a high-voltage discharge unit connected in series between the workbench and the wire electrode unit and in parallel with the low-voltage ignition unit, and a control unit storing a voltage threshold value. The low-voltage ignition unit has a first transistor, a current-limiting resistor and a low-voltage power supply connected in series between the workbench and the electrode unit, the high-voltage discharge unit has a second transistor and a high-voltage power supply connected in series between the workbench and the electrode unit, the control unit electrically connects the first transistor and the second transistor, and the wire cutting discharge processing method includes the following steps: (A) the control unit controls the first transistor to switch from a first open circuit state to a first open circuit state; (A) the control unit controls the first transistor to switch from the first connection state to the first disconnection state, and controls the second transistor to switch from a second disconnection state to a second connection state, driving the high voltage power supply to perform discharge processing on the workpiece through the ignition discharge channel; (C) the control unit detects a corresponding connection between the electrode unit and the workpiece. The control unit determines the gap voltage and compares the gap voltage value with the voltage threshold value; and (D) if the control unit determines that the gap voltage value is less than the voltage threshold value, the control unit outputs a pulse signal with a pulse duration to the second transistor according to a predetermined cycle to control the second transistor to switch between the second open circuit state and the second open circuit state, thereby partially melting the electrode unit and applying the melted portion of the electrode unit to the workpiece. A wire cutting discharge processing method is applied to a discharge processing device, which is suitable for performing discharge processing on a workpiece and includes a workbench for placing the workpiece, a wire electrode unit corresponding to the position of the workbench, a low-voltage ignition unit connected in series between the workbench and the wire electrode unit, a high-voltage discharge unit connected in series between the workbench and the wire electrode unit and in parallel with the low-voltage ignition unit, and a control unit storing a current threshold value. The low-voltage ignition unit has a first transistor, a current-limiting resistor and a low-voltage power supply connected in series between the workbench and the electrode unit, the high-voltage discharge unit has a second transistor and a high-voltage power supply connected in series between the workbench and the electrode unit, the control unit electrically connects the first transistor and the second transistor, and the wire cutting discharge processing method includes the following steps: (A) the control unit controls the first transistor to switch from a first open circuit state to a first open circuit state; (A) the control unit controls the first transistor to switch from the first connection state to the first disconnection state, and controls the second transistor to switch from a second disconnection state to a second connection state, driving the high voltage power supply to perform discharge processing on the workpiece through the ignition discharge channel; (C) the control unit detects a corresponding connection between the electrode unit and the workpiece. discharge current, and compare the current value of the discharge current with the current threshold value; and (D) if the control unit compares the current value of the discharge current to be less than the current threshold value, it outputs a pulse signal of a continuous pulse time to the second transistor according to a predetermined cycle to control the second transistor to switch between the second open circuit state and the second open circuit state, thereby partially melting the electrode unit and applying the melted portion of the electrode unit to the workpiece.

Images