JPH0475780A - Arc welding machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Field of Application in Industry> The present invention relates to an arc welding machine that automatically generates an arc between a tungsten electrode and a wire to perform welding. , there is a means to deal with this when the tungsten electrode is welded to the workpiece and twists. <Prior art> Arc welding using a tungsten electrode has been widely known for a long time, but conventional arc welding It is used for welding relatively large parts.

Here, it may be necessary to assemble small parts by welding.

For example, the nozzle l for drug injection shown in FIGS. 5(a) and 5(b) is a small part with an outer diameter and height of about several nanometers, but it has a nozzle hole 3a for the following reasons. The orifice plate 3 and the base 2 are each manufactured separately from stainless steel.18 These must be assembled and manufactured by welding.

In other words, the nozzle hole 3 has a diameter of several tens of μm or less.
a is to make the injected drug in a good injection state,
The length of the hole also needs to be set accurately, and if the nozzle l is made as an integral part from the beginning, it is not possible to achieve such precision of the nozzle hole 3a. Therefore, the orifice plate 3 is made from a plate material and the predetermined nozzle is set. It is necessary to form a hole 3a and connect it to the base 2. Some of the chemicals injected from the injection nozzles are chemically quite active, and they react with metals such as copper, aluminum, and lead, causing deterioration of the medicine and the formation of crystalline substances, which can lead to nozzle clogging. Because of this, it is necessary to make the nozzle l stainless steel. However, even if the base 2 and orifice plate 3 are made of stainless steel, the solder and wax will react with the chemicals when soldering or binding them, and when bonding with adhesive, has a problem that it lacks reliability in terms of durability in use, and it is necessary to weld the base 2 and orifice plate 3.

In this way, a chemical injection nozzle must be manufactured by separately processing the base and orifice plate from stainless steel and assembling them by welding, but a conventional arc welding machine is used for this welding. I couldn't do that. In other words, because conventional arc welding machines are designed for welding relatively large parts, the arc current value is large, and if this machine is used to weld small parts, the parts will be destroyed by the excessive arc. Otherwise, parts may be blown off. On the other hand, when the arc current value is kept small in a conventional arc welding machine, an arc cannot be generated.

Due to the above-mentioned circumstances, it has been strongly desired to realize an arc welding machine that can weld small parts without any problems.

Therefore, as shown in FIG. 6, the applicant of the present application has created a small An arc welding machine that can generate a small arc in a minute area using arc current and can melt small parts in a minute area to assemble them by welding has already been put into practical use.

However, as shown in FIG.
A new problem had arisen: welding with 2.

This is because the molten pool formed on the workpiece W by the arc is minute, so it cools and hardens within a relatively short period of time.
If you miss the timing to move away from Wari W,
Electrode welding as described above frequently occurred.

While the electrode 22 is welded to the workpiece W, it is not possible to proceed with the blow welding operation. Therefore, storing the electric power to be supplied to the electrode 22 is not only wasted, but also the electrode 22 is It was dangerous to carry out the repair work to separate it from the workpiece W.

The present invention was made in view of the above-mentioned conventional circumstances, and when the tungsten electrode is welded to
It is an object of the present invention to provide an arc welding machine having means for dealing with this problem.

<Means for Solving the Problems> The arc welding machine according to the present invention detects that a tungsten electrode has contacted a workpiece, and automatically generates an arc between the tungsten electrode and the workpiece to perform welding. The arc welding machine is equipped with a welding detection means for detecting welding between the tungsten electrode and the workpiece, and a maintenance means for setting the power supply system to the tungsten electrode in a standby state when the tungsten electrode and the workpiece are melted. It is characterized by:

<Function> When the tungsten electrode and the workpiece are welded together, the air welding machine of the present invention puts the power supply system to the tungsten electrode in a standby state. It is possible to avoid the danger of repair work in which electrodes are separated from the W7.The present invention is particularly effective when applied to arc welding machines used for welding small parts where electrodes tend to adhere. A similar effect can be obtained by applying L/ to a conventionally common arc welding machine used for welding parts.

<Example> The present invention will be specifically explained based on examples.

The external configuration of an arc welding machine according to an embodiment of the present invention is shown in a first example.
As shown in the figure.

The arc welding machine of this embodiment is equipped with a controller 1o, and this controller 10 allows IT! It controls the supply of current to the pen 11 and workbench 12, and the supply of argon gas from the cylinder 13 to the welding plate 11. In addition, a foot switch 14 for performing various manual operations and a microscope 15 having a shutter mechanism to protect the operator's eyes from arcs are connected to the controller 10. The reason for this is to carry out detailed welding work on small parts, and the operator uses this microscope I5 to visually check the welding location while performing the work.

Note that 16 is an outlet for connecting to an AC 100V power source.

As shown in detail in FIG. 3, the welding ben 11 has a tungsten electrode 22 shown in FIG.
The cylindrical body 21 is supported by the tube 23.
The argon gas supplied within the tungsten electrode 22 is supplied to the vicinity of the tungsten electrode 22 to generate an arc. Note that 27 is a cable that supplies arc current to the tungsten electrode 22 and a drive current to the solenoid 24.

This welding ben 11 has a welding prevention mechanism 1-j with the workpiece.
It is set up. That is, the tungsten electrode 22 is attached to the movable element 25 of the solenoid 24, and the movable element 25 is biased toward the tip side by the spring 26. Therefore, the tungsten electrode 22 is moved from the tip of the cylindrical body 21 to a certain place. Although it is held in a constant protruding state, if an arc is generated during welding work, the detecting means ζ described later
This is detected and the solenoid 24 is activated to slightly retract the tungsten electrode 22 against the spring 26, thereby preventing welding of the workpiece and the tungsten electrode 22.

Figure 2 shows the circuit configuration of the arc welding machine described above.

In the figure, 30 is a central processing unit (CPU),
The controller 10 plays a central role in automatic welding control.

31 is a capacitor, and this capacitor 31 is a CPU
AC 1 via the charging switch 32 controlled by 3O
The capacitor 31 is charged with a charging power source 33 connected to the 00V power source ζ. capacitor 3
The other electrode of I is connected to the workbench 12. A discharge switch 36 is provided between the electrodes of these capacitors 31, and this switch 36 is connected to the CPU 3.
Controlled by 0.

A resistor 37 is provided that bypasses the thyrisk switch 34 and allows a minute current to flow, and this minute current is led to a voltage level detection circuit 38, where various states are detected and the CP
[, J 30 is input. For example, when the tungsten electrode 22 is brought into contact with a workpiece placed on the workbench 12, the voltage drops momentarily and this state is detected. ] When the tungsten electrode and the workpiece are welded together, this state can be detected because the voltage does not rise. The composition is tno.

Further, as described above, the switches 32 and 36 controlled by the CPU 30 constitute a maintenance means that puts the power supply system to the tungsten electrode 22 in a standby state when the tungsten electrode 22 and the workpiece are welded together.

The above-mentioned charging circuit is provided with a transformer 39 for detecting arc current, and occurrence of an arc is detected by detecting this arc current with a detection circuit 40, and this detection signal is input to the CPU 30.

Solenoid driver 41 controlled by CPU 30
The driver 41 drives the tungsten electrode 22, the solenoid 24, and the cylinder 13.
The electromagnetic valve solenoid q2 provided in the argon gas supply path from to the welding vent 11 and the solenoid 43 that drives the shutter mechanism of the microscope 15 are driven.

Note that the control signal from the foot switch 14 is also sent to the CPU 30.
5, and various manual operations such as resetting the control system are performed based on this input.

The operation of the arc welding machine having the above configuration will be explained with reference to the flowchart shown in FIG.

First, when the main power of the welding machine is turned on and the circuit is activated, all switches, actuators, and valves installed in the welding machine are turned off to set it to the initial state (Step S
l).

Next, the switch 36 is turned on to discharge the capacitor 31 once (step S2), and then the switch 36 is turned off and the charging switch 32 is turned on to charge the capacitor 31 (step S3).

Next, it is confirmed based on the signal from the voltage 1 novel detection circuit 38 that the tungsten electrode 22 is not welded to the workpiece (step S4). As a result, when the electrode 22 is welded, the switch 32 is turned off to cut off the charging power, and the switch 36 is turned on to temporarily discharge the capacitor 31 (step S5).
The power supply system to the electrode 22 is placed in a standby state until the operator resets it using the foot switch 14 (step S6).
). Therefore, while the worker is working to separate the welded electrode 22 from the workpiece, relatively high-voltage charging power is not supplied, which prevents wasteful power consumption and prevents the work. can be done safely.

On the other hand, when the electrode 22 is not welded, the operator determines whether or not the tip of the tungsten electrode 22 has touched the tip based on the signal from the voltage level detection circuit 38. A standby state is maintained until the area to be welded is applied (step S7).

Next, when the tip of the tungsten electrode 22 comes into contact with the tip, the solenoid valve 42 is turned on to supply argon gas to the welding vent 11, and the solenoid valve 43 is turned on and the microscope 15 is turned on. The field of view is blocked by a shutter mechanism (Ste Tsubu S8). Meanwhile, in order to ensure that the shutter is closed in consideration of the delay in the operation of the solenoid 43, a slight delay time (0.2 seconds in this embodiment) is provided (step S9), and the shutter is closed. Turn on the risk switch 34 to generate an arc (step 5)
10).

As mentioned above, the field of view of the microscope 15 is cooled based on the contact of the tungsten electrode 22 in order to protect the eyes of the operator from the arc that is subsequently generated. Since the contact position is specified as 22, there is no problem with operation.

Next, based on the detected value of the arc current detection circuit 40, it is determined whether an arc has occurred within a predetermined time period (2 seconds in this embodiment).If no arc has occurred during this period, the electromagnetic The valve solenoid 4.3 is turned off to stop the supply of argon gas, the solenoid 4.3 is turned off to open the shutter mechanism of the microscope 15, and the cyrisk switch 34 is turned off to stop the supply of arc current. ) = t (step 512), the switch 36 is turned on to discharge the capacitor 31 (step 513).
), re-execute from step S3 above.

On the other hand, within the predetermined time: change occurred L/Tosa, So1Tonoid 2/1. is turned on to draw in the tungsten electrode 22, the switch maid 43 is turned off to open the shutter mechanism of the microscope 15, and the cyrisk switch 34 is turned off to stop supplying the arc current (step 514)6, that is, The detection value of the arc current detection circuit 40 is used as the starting timing to quickly start the solenoid after the arc occurs.
The tunoid 24 is turned on to separate the tungsten electrode 22 from the workpiece to prevent the tungsten electrode from welding ( ) to the welded part formed by the arc.

Then, after a delay of the time required for the operator to pull the welding ben 11 far away from the welding ben 7 (in this example, 034 seconds) (step 515), the solenoid 24 is turned off and the tungsten electrode 22 is returned to its original state by the spring 26. At the same time, the solenoid valve solenoid 42 is turned off to stop the supply of argon gas (step 516).
), the switch 36 is turned on to discharge the capacitor 31 (step 9.17), and the process is re-executed from step S3.

In this embodiment, as described in ``-'', the dungesten electrode 22 is prevented from welding to the welded part, but if welding still occurs even after this, the steps from step S4 to step described above are performed. The processing in S6 prevents unexpected problems from occurring.

In the above embodiment, the electrode 2 is connected from the charged capacitor 31.
By supplying power to the electrode 22, the generation of arc is suppressed for a short time and damage to the workpiece, which is a small component, is prevented. and connect this switch to the CPU
It is also possible to control the arc generation time by turning it on for a short period of time.

Furthermore, the welding detection means may be one that detects welding from a minute current that is passed by bypassing the Zyristor switch, or other known means such as one that detects welding optically.

<Effects of the Invention> According to the present invention, the power supply system to the tungsten electrode is placed in a standby state when the tungsten electrode and the workpiece are welded together, thereby preventing unnecessary power consumption.
Safety can be ensured during repair work in which the electrode 22 is separated from the workpiece W.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the overall configuration of an arc welding machine according to an embodiment of the present invention, FIG. 2 is a block diagram showing the circuit configuration of an arc welding machine according to an embodiment of the present invention, and FIG. FIG. 4 is a sectional view showing the configuration of a welding pen of an arc welding machine according to an embodiment of the present invention, FIG. 4 is a flowchart explaining the operation of the arc welding machine according to an embodiment of the present invention, and FIG. FIG. 5(b) is a perspective view of the nozzle for drug injection, FIG. 5(b) is a cross-sectional view of the nozzle for drug injection, FIG. 6 is a perspective view showing the tip of the tungsten electrode, and FIG. 7 is welding of the tungsten electrode and the workpiece. FIG. 11 is a welding pen, 14 is a foot switch, 22 is a tungsten electrode, and 30 is a CPU. 31 is a capacitor, 32 and 36 are switches, 33 is a charging power source 37 is a resistor, 38 is a voltage level detection circuit, and W is a workpiece. Figure 3

Claims (1)

[Claims] Detects that the tungsten electrode has contacted the workpiece,
The arc welding machine automatically generates an arc between the tungsten electrode and the workpiece to perform welding, and the tungsten electrode and the workpiece are welded together. An arc welding machine characterized by being equipped with a maintenance means that sometimes places a power supply system to a tungsten electrode in a standby state.