JP4854927B2 - Two-stage welding machine and method for operating the same - Google Patents

Description

  The present invention relates to the art of electric arc welding, and more particularly to an electric arc welder having two-stage or two-mode operation and a method performed by the two-stage electric arc welder.

  As background art, Patent Document 1 is cited as a reference together with documents cited as a reference in this specification. U.S. Patent No. 6,057,028 shows a switch that shifts between DIP welding and pulse welding, which is cited as background art.

GMAW type electric arc welders are often powered by a fast switching power supply with a controller for controlling the current waveform of the welding process. Cleveland, Ohio Lincoln
Electric Company has developed the concept of an electric arc welder with a waveform shaper that controls the shape of the current waveform during each cycle by using high frequency current pulses where the magnitude of each pulse is controlled by a pulse width modulator. . In these welder, the waveform of the current, accurately controlled by pulse welding, constant voltage welding, spray welding, pulse welding, the various welding processes such as short-arc CV welding and STT (R) Welding . In these processes, the waveform for each welding cycle results in a series of welding cycles controlled by a pulse width modulator to perform the specified process. These arc welders are really versatile, but they are operated in a selected mode by controlling the pulses produced by the wave shaper.
US Patent Application No. 866358 US Pat. No. 4,888,969

  The main object of the present invention is to provide a two-stage electric arc welder that alternates two welding processes during a single welding operation.

  Another object of the invention is the above two-stage arc welding wherein the arc welder has a counter that counts one process cycle to determine when a shift should be present in the process being performed by the welder. Is to provide the machine.

  Another object of the present invention is to provide the above-described two-stage arc welder that performs a pulse welding process until a non-temporary short circuit is detected. The two-stage welder is then shifted to the second mode of operation to clear the short.

  Another object of the present invention is to provide a method for operating the above two-stage arc welder.

  Yet another object of the present invention is the operation of a two-stage welder as described above, wherein the two stages include one of many combinations of a separate first welding process and a separate different second welding process. The two processes alternate between before and after a single welding operation.

  These and other objects will become apparent from the following description in view of the drawings.

  The present invention relates to an electric arc welder of the type described above, in which the controller shifts between two separate and different welding processes or welding modes. In accordance with the present invention, the pulse former or pulse generator shapes a series of pulses that form the first welding process. The controller is shiftable and then performs the second welding process by realizing a series of different pulse shapes that constitute different modes of operation. By counting the number of operation cycles in the first mode, the first process ends and the second process begins. Thereafter, the next processing cycle is counted until they reach a set number indicating that the welder should shift back to the first welding process. As such, the electric arc welder has the ability to perform two separate welding processes by switching the controller from one mode of operation to another mode of operation. This unique two-stage or two-state operation of the electric arc welder allows the welder to perform a welding operation using alternating first treatment and then second treatment. For example, the high energy process is performed in a short time and then the welder is converted to a low energy welding process. If the two processes are STT, a low energy STT cycle is realized, followed by a high energy STT cycle. Thus, in one aspect, the first process is a high energy process and the second is a low energy process. The counted number of each process cycle is used in the welding process to perform the entire welding operation by successively implementing the first and second welding processes. For example, in one particular aspect, the first process is a constant voltage spray process at a high temperature. The second process is a pulsed GMAW or low temperature welding process. In a welding operation, the controller first implements a first process for a number of cycles and then implements a second process for a number of cycles. In another aspect of the invention, the first process is a pulse welding process where the pulses have high energy or high temperature. This is used in turn in the low temperature STT welding process for a number of cycles. By switching between the pulse cycle and the STT cycle, the entire desired welding operation is performed. In another aspect, the first process is a high temperature pulse welding process. This process replaces the second welding process which is a short arc constant voltage welding process. In yet another aspect, the first process is a high temperature pulse process. The second welding process is determined by closed loop feedback of the power at which the pulse energy is activated. Yet another example of the present invention is an embodiment in which the first sequence of pulses of the pulse welding operation is electrode positive and produces a high temperature. The second series of pulses is a negative pulse welding process consisting of electrode constant voltage pulses. By shifting between these welding processes, the actual welding operation is controlled to optimize the performance of the welder.

  According to yet another configuration of the invention, the first welding process of the two-stage or two-state electric arc welder is a pulse welding process. This process continues until the arc voltage indicates a short circuit. Next, the two stage welder is shifted to a short clear welding process, such as an STT welding cycle. In a preferred embodiment, the signal shifted from the pulse welding process depends not only on the indication of a short due to a drop in arc voltage but also on the time of the timer. Control of the arc welder shifts from the first welding process in the pulse mode to the short clear process only when the short is maintained for a set time. The timer is preferably set to indicate that the short is maintained for longer than a set time in the range of at least 1.0 ms and preferably at least 0.2 ms to 0.5 ms. As a result, the electric arc welder only shifts to the second welding process to clear the detected short circuit only when a short actually exists instead of a temporary short.

  In accordance with the present invention, a negative electric arc welder provides a high speed switching power supply with a controller for producing first and second welding processes between a gap between a blank and a welding wire traveling toward the blank. Is done. The first process uses the first current waveform and the second process uses the second current waveform. A circuit is used to shift between the first welding process and the second welding process, and the circuit includes a counter that counts the waveforms of the first and second processes. The welder shifts from being processed to another welding process when the count of the waveform of the welding process being processed reaches a pre-selected number for each welding process. By using this two-stage welder, the arc welder can shift between two separate distinctly different welding processes according to counts or other parameters.

  In another configuration of the invention, there is a two-stage arc welder of the type including a high speed switching power supply with a controller for producing a pulse wave welding process and a welding process to clear a detected short. The circuit is activated to generate a short signal when the arc voltage is lower than a value indicating a short, and there is a switch that shifts the controller from pulse wave processing to short clear processing by a processing shift signal generated by the generation of the short signal. . In the configuration of the present invention, the two stage welder retains a predetermined time short signal which is defined as longer than about 1.0 ms and preferably longer than a set time in the approximate range of 0.2-0.5 ms. Only when includes a timer that generates a shift signal. As a result, when the short is maintained for a preselected time, the two-stage welder is shifted from the pulse mode of operation to the short clear mode of operation. In a preferred embodiment, the short clear mode of operation is an STT welding process.

According to another configuration of the present invention, a method for operating an electric arc welder of the type including a high speed switching power supply with a controller is provided. The controller produces first and second welding processes between the gap between the blank and the welding wire that is advanced toward the blank by the wire feeder. The first process of the method has a first current waveform. The second process has a second waveform. The method includes shifting between a first welding process and a second welding process and is implemented by counting the waveforms of the first and second processes. Welding process is performed, when it reaches the number count of performed operation being the waveform is selected, is shifted to the other process. In a further configuration of the present invention, a method is provided for operating an electric arc welder including a high speed switch and a power supply with a controller for producing a pulse wave process and a short clear welding process. The method includes generating a short signal when the arc voltage is lower than a value indicating a short circuit, and then shifting the controller from pulse wave processing to short clear processing by a shift signal generated by detection of the short circuit. In this way, a shift signal is produced only when the short signal is held for a predetermined period of time which is shorter than 1.0 ms in practice and actually in the approximate range of 0.20-0.50 ms.

The drawings are only for the purpose of illustrating preferred embodiments of the invention and are not intended to limit the invention. With reference to the drawings, FIG. 1 shows a novel two-stage welder A having a power supply 10 including a high-speed switching power supply, depicted as an inverter 12 having a three-phase power input 14 that is converted to a DC rail by a rectifier 16 on lines 20 and 22. Indicates. The output winding 30 of the inverter 12 is the primary winding of the transformer T having a secondary winding 32 for the supply current to the rectifier network 40. This network provides a level of current with a positive lead 42 and a negative lead 44. A standard small inductor 50 is connected to a standard contact tip 54 and passes through a welding wire 60 that forms an electrode E remote from the material W through 54 and through the gap of the arc through which current flows during the arc welding process. Define. The welder A performs many types of electric arc welding by passing a preselected shape of current between the gaps between the electrode E and the blank W. As the arc melts the wire 60 and the material W and performs the welding operation, the wire feeder 100 pulls the wire from the reel 102 at a speed (WFS) determined by the rotational speed of the motor 104. This speed is read by feedback tachometer 110 and is controlled by the input voltage from error amplifier 114 to pulse width modulator 112. The amplifier has a first input 120 that is a voltage representing the desired wire feed rate (WFS). This speed can be controlled by analog circuitry or more suitably from a look-up table from waveform shaper 180. The input voltage 120 determines the speed of the motor 104 and its actual speed is monitored by the tachometer 110 for comparison with the voltage on the line 120. The actual speed feedback is the voltage on the input line 122. In this way, the wire supply speed is adjusted with the welding process realized by the welder A. The current waveform between electrode E and material W is a type of software that includes a software pulse width modulator 132 for producing a voltage on output control line 134 at a pulse repetition rate determined by the set frequency of oscillator 136. Determined by controller 130. In this manner, the high frequency pulse on line 134 is controlled by the voltage on line 140, which is the output of second error amplifier 150 having a first input controlled by current sensing or sensing shunt 152. The voltage on line 154 indicates the arc current of the welding process. The command signal on line 160 is compared to the actual arc current represented by the voltage on line 154 to cause pulse width modulator 132 to follow the desired waveform from waveform shaper or generator 180 via command line 160. The wire feed rate to the error amplifier 114 is also from the wave shaper or generator. The generator 180 is of a synergistic type, and both the command signal 160 and the wire feed rate signal or voltage (WFS) on line 120 are adjusted.

In accordance with the novel configuration of welder A, a switch 190 is provided which is a software switch having a first position 192 and a second position 194 in practice as shown in FIG. When in position 192, waveform shaper 180 is controlled according to a first process A from process control system 200 for process A. In this method, the process control system 200 is connected to the synergistic waveform shaper 180, and the process A is realized from the waveform shaper 180 by the controller 130. In a similar manner, when the switch 190 is in position 194, the process control system 202 causes the waveform shaper 180 to implement the second process B by the command line 160 signal. Thus, by shifting switch 190 between positions 192 and 194, two separate welding processes are performed by welder A. Of course, if such an operation is desired, it is within the scope of the present invention that the welder can process more than two welding processes one after the other using a switch 190 having more than two positions. It is. In practice, it is preferred that only two separate welding processes are performed alternately by the welder A. According to another configuration of the present invention, the position of switch 190 is controlled by the logic of dotted line 210 from the output of cycle counter 212. The counter counts each cycle during either process A or process B. At the end of the count, the logic of line 210 shifts switch 190 to another position to implement another welding process, as set by count selector 214 or count selector 216. Counter 212 counts up to several CA, then the counter is shifted to the processing B to be maintained until the count CB. Next, the switch 190 returns to the first process, that is, the process A. In a preferred embodiment, one of the treatments is a high temperature treatment and the other is a low temperature treatment. The numbers CA and CB are essentially the same. Thus, the welding process includes a cold part and a hot part that are repeatedly implemented during the entire welding process to control the performance of the welding operation, whether it is STT, pulse or otherwise. As shown, the various welding processes can be alternately selected by a counter. In fact, the welder A interacts and the shift from one process to the other is determined by parameters so that it can be distinguished from the count. For example, the voltage sensor 170 produces a voltage at 172 that detects a short, which is used in FIG. 2 for the transition between the first process A and the second process B, the second process being an arc clear process. is there. The counts are dramatically different and the interacting parameters can be selected to shift to a preselected process after the transition of a given process to a detectable welding condition.

In practice, process A is usually a high energy process and process B is a low energy process. The count numbers CA and CB are essentially the same. To change the welding operation, the number CA increases or the number CB decreases to increase the temperature during the welding operation. In a similar manner, to reduce the temperature, the number CA decreases or the number CB increases. Of course, a combination of these increases or decreases can be used to select the desired total temperature during the welding operation. In a preferred embodiment, Process A and Process B are the same, but have different sized waveforms. It is pulse welding or STT welding. However, according to the present invention, the processing is completely diverse. For example, in practice, process A is a high temperature constant voltage spray process and process B is a pulsed GMAW low temperature process . The counter 212 is set by the count selectors 214 and 216 so as to obtain a desired total temperature for the welding operation. In practice, Process A is a high temperature pulse welding process, while Process B is a slower wire feed rate STT welding process. In practice, the process A is a higher-temperature pulse welding process, and the process B is a short arc constant voltage process. In another configuration of the invention, process A is a pulse welding process and process B is a closed loop control process, such as a process in which the current is controlled by the output power. A further realization of the invention is also when process A is a pulsed electrode positive and process B is an electrode negative constant voltage welding process. In that realization of the present invention, a polarity switch is added to the output circuit before the inductor 50 and the polarity circuit is shifted to the same time as the switch 190. Other implementations of the present invention include various combinations of welding processes to perform the desired overall welding operation.

The interacting control system 220 is schematically depicted in FIG. 2, and the waveform generator and control 222 produces a voltage on the control line 134 as described above. Control 130 is at block 222. The voltage controls the power supply 12, which is monitored by the process control network 224 along with the voltage on line 172 from the voltage sensor 170, as shown in FIG. The process control network timer 226 is generally set for a time longer than about 1.0 ms and preferably longer than a set time in the approximate range of 0.2-0.5 ms. The output from the timer network is the logic on line 232 to decision block 230 to determine if there is a short circuit detected for a time longer than the timer 226 time setting. The position of switch 190 is controlled by decision block 230. When there is a short that exceeds the set time of timer 226, switch 190 is shifted to position 194. Thus, when there is a long-term non-temporary short, switch 190 shifts to another position 194 to implement the second welding process. In this implementation of the invention, the first process is a pulse waveform that is controlled according to a waveform determined by the system shown as block 240. Block 242 represents the system that produces the STT waveform or other short clear welding process. System 220 performs a first mode of operation defined as a pulse waveform controlled by the system represented by block 240. Whenever there is a short, the voltage on line 172 drops below the threshold. This determines the short circuit. The detected condition is designated by a timer 226 for a time. If the short time exceeds the timer set time, the logic on line 232 indicates to the decision block that a non-temporary actual short circuit exists. This logic immediately shifts software switch 190 to the arc clear welding process shown as the STT process. When the short is cleared by the short clear process, the voltage on line 172 immediately shifts to the plasma level or arc voltage. This is above the threshold and causes decision block 230 to shift switch 190 to position 192 for implementation of the pulse waveform controlled by the system represented by block 240. As a result, the system 220 does not include a cycle counter and senses the welding parameters for the actual shift from one welding process to another. This occurs quickly and occurs whenever a selected parameter is detected.

3 and 4, the system 250 includes a low temperature welding process represented by block 260. Process A is a low temperature STT welding process. In a similar manner, the high temperature STT welding process is represented by block 262. The counter 212 processes the first STT pulse 260a as shown in FIG. After the desired number of STT pulses 260a has been counted by cycle counter 212, switch 190 is shifted to position 194 by the logic on line 210. This generates a large or hot STT pulse 262a, as shown in FIG. These hot pulses are counted according to a selected number for counter 212. In this method, the number of cold and hot STT waveforms or cycles are adjusted to determine the total temperature during the welding operation.

  The present invention includes two or more stages of welders that in turn realize distinctly different welding processes. Preferably, the duration of these processes is determined by a counter, but the parameters can be used for shifting between welding processes. Only representative processes are discussed and only the welding process is used when implementing the present invention.

FIG. 2 is a combined block and wiring diagram illustrating a preferred embodiment of a two stage arc welder for the present invention. FIG. 6 is a block diagram format flowchart of a method and operation for a two-stage arc welder that shifts a welding process in which a detected non-temporary short is occurring. FIG. 6 is a block diagram format flowchart illustrating a further realization of a two stage welder constructed in accordance with the present invention. 4 is a current graph illustrating the operation of a two-stage welder according to the realization of the present invention depicted in FIG. 3.

Explanation of symbols

A 2-stage welding machine E Electrode T Transformer W Material 10 Power supply 12 Inverter 14 Input 16 Rectifier 20 Line 22 Line 30 Output winding 32 Secondary winding 40 Rectifier network 42 Lead 44 Lead 50 Inductor 54 Contact tip 60 Winding wire 100 Wire feeder 102 Reel 104 Motor 110 Feedback tachometer 112 Pulse width modulator 114 Error amplifier 120 First input 130 Software controller 132 Pulse width modulator 134 Output control line 136 Oscillator 140 Line 150 Error amplifier 152 Shunt 154 Line 160 Line 170 Voltage sensor 172 Line 180 Waveformer 190 Switch 192 First position 194 Second position 200 Process control system 202 Process control system 210 Dotted Line 212 Cycle Counter 214 Count Selector 216 Count Selector 220 Control System 222 Waveform Generator and Control 224 Processing Control Network 226 Timer 230 Decision Block 232 Line 240 Block 242 Block 250 System 260 Block (Low Temperature STT)
260a STT pulse 262 block (high temperature STT)
262a STT pulse

Claims (9)

  A high speed switching power supply with a controller for producing a first or second welding process between a gap between a workpiece and a welding wire traveling toward the workpiece and the first current waveform using a first current waveform. A circuit for shifting between one welding process and the second welding process using a second current waveform, the circuit for counting the waveforms of the first and second processes A counter and a circuit for shifting from the process being processed to another welding process when the count of the waveform of the welding process being processed reaches a preselected number of the welding processes; and An electric arc GMAW welding machine, wherein the welding process is a short clear welding process or a CV spray process. To produce a first welding process using a first current waveform or a second welding process using a second current waveform between a gap between a workpiece and a welding wire traveling toward the workpiece. A method of operating an electric arc GMAW welder comprising a high-speed switching power supply with a controller and wherein the first welding process is a short clear welding process or a CV spray process,
(A) shifting between the first welding process and the second welding process;
(B) counting the waveforms of the first and second processes; and
(C) Shifting from being processed to another welding process when the waveform count of the welding process being processed reaches a preselected number of the welding processes.
A method of operating an electric arc GMAW welder characterized in that . A high speed switching power supply with a controller for producing a first or second welding process between a gap between a workpiece and a welding wire traveling toward the workpiece and the first current waveform using a first current waveform. A circuit for shifting between one welding process and the second welding process using a second current waveform, the circuit for counting the waveforms of the first and second processes Including a counter and circuitry for shifting from the process being processed to another welding process when the waveform count of the welding process being processed reaches a preselected number of the welding processes, and the second An electric arc GMAW welding machine, wherein the welding process is a short clear welding process or a short arc CV process . A high speed switching power supply with a controller for producing a first or second welding process between a gap between a workpiece and a welding wire traveling toward the workpiece and the first current waveform using a first current waveform. A circuit for shifting between one welding process and the second welding process using a second current waveform, the circuit for counting the waveforms of the first and second processes A counter and a circuit for shifting from the process being processed to another welding process when the count of the waveform of the welding process being processed reaches a preselected number of the welding processes; and An electric arc characterized in that the welding process is a high temperature process with a closed power supply feedback loop, and one of the first and second welding processes is a short clear welding process or a CV spray process. MAW welding machine. A first welding process using a first current waveform or a second welding process using a second current waveform between a gap between a workpiece and a welding wire traveling toward the workpiece by a wire feeder A method of operating an electric arc GMAW welder including a high speed switching power supply with a controller for producing a second and the second welding process is a short clear welding process or a short arc CV process, the method comprising:
(A) shifting between the first welding process and the second welding process;
(B) counting the waveforms of the first and second processes; and
(C) When the waveform count of the welding process being processed reaches a preselected number of welding processes, the process being processed is shifted to another welding process.
A method of operating an electric arc GMAW welder characterized in that . A first welding process using a first current waveform or a second welding process using a second current waveform between a gap between a workpiece and a welding wire traveling toward the workpiece by a wire feeder A high-temperature welding process including a high-speed switching power supply with a controller for producing a first power supply feedback loop, wherein the first welding process is a closed one of the first and second welding processes Is a method of operating an electric arc GMAW welder that is a short clear welding process or a CV spray process,
(A) shifting between the first welding process and the second welding process;
(B) counting the waveforms of the first and second processes; and
(C) When the waveform count of the welding process being processed reaches a preselected number of welding processes, the process being processed is shifted to another welding process.
A method of operating an electric arc GMAW welder characterized in that . A power supply including a fast switching inverter for creating a current waveform for welding between the electrode and the workpiece, wherein the waveform is generated by a waveform generator, the waveform generator selected to the waveform generator An output that controls a series of current control pulses from a pulse width modulator according to an input circuit, the pulse having a width that determines the real-time current of the waveform, and the selected input circuit between two welding processes The switch is switched upon receipt of a signal to the switch, and the switch is operated in response to a counter that counts the cycles of the waveform, and is one of the two welding processes. Is a short clear welding process or a CV spray process . A power supply including a fast switching inverter for creating a current waveform for the welding process between the electrode and the workpiece, wherein the waveform is generated by a series of current control pulses from a pulse width modulator, the pulse being a real-time current of the waveform And a switch that can be switched between two welding processes, and upon receipt of a signal to the switch, the switch is switched and the switch is responsive to a counter that counts the cycles of the waveform The electric arc welding machine is characterized in that one of the two welding processes is a short clear welding process or a CV spray process . A power supply including a fast switching inverter for creating a current waveform for welding between the electrode and the workpiece, wherein the waveform is generated by a waveform generator, the waveform generator selected to the waveform generator A switch having an output for controlling the pulse width modulator in accordance with the input circuit, and switching the selected input circuit between two welding processes, the switch being switched upon receipt of a signal to the switch; and An electric arc welding machine characterized in that the switch is operated in response to a counter that counts the cycles of the waveform, and one of the two welding processes is a short clear welding process or a CV spray process.

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