JPH0366478A - Automatic butt welding machine - Google Patents

Abstract

PURPOSE:To automatically and exactly decide the welding quality by comparing the melting quantity at the time of finishing welding detected by a melting quantity detector with the preset reference melting quantity to decide the propriety of the melting quantity at the time of finishing welding. CONSTITUTION:The melting quantity detector 12 detects a traveling stroke of a melting quantity detection arm fixed on a movable electrode 6 at the time of welding and detects the melting quantity from both end faces 7a and 8a in opposition of a couple of members 7 and 8 to be welded. A welding quality deciding device 15 compares the melting quantity at the time of finishing welding detected by the welding quantity detector 12 with an upper limit value and a lower limit value of the preset proper melting reference quantity and decides the propriety of the melting quantity at the time of finishing welding. By this method, the welding quality on a welded product can be decided automatically and a accurately.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an automatic butt welding machine, and particularly to an automatic butt welding machine that can automatically determine the quality of welding of a welded product at the end of welding.

[Conventional technology]

A conventional automatic butt welding machine generally includes a power source, a pair of electrodes each connected to the power source via a transformer, and holding each member to be welded so that opposite end surfaces of the pair of members to be welded face each other. A pressurizing device such as a pneumatic cylinder is provided for pressing the movable electrode of the pair of electrodes against the fixed electrode in order to press the opposing end surfaces of the contact members held by the electrodes into contact with each other. Further, the operation of the pressurizing device is controlled by a control device. In welding with this butt welder, if the amount of melt from both opposing end faces of a pair of welded parts is too small, the welding strength will be low and the weld quality will deteriorate, but even if the amount of melt is too large, it will not be enough. Although a high welding strength can be obtained, the welding paris height increases and the welding quality deteriorates. Therefore,
It is preferable to keep the amount of melting appropriate.

[Problem M that the invention attempts to solve]

By the way, since the automatic butt welding machine described above is not equipped with a mechanism for determining whether the welding quality is good or bad, conventionally, for example, the welding quality of the welded product is determined as follows. In other words, an index is engraved with a scriber at a predetermined distance from the opposing end surfaces of each member to be welded, and before welding, with both opposing end surfaces of a pair of welded members in close contact, the distance between the two indicators is determined. Measure with a caliper, and after welding, measure the distance between both indicators again with a caliper. Then, the quality of welding is determined based on the difference in distance between the indicators before and after welding, that is, the amount of melting from both opposing end surfaces of the pair of welded members. However, such a method for determining welding quality is extremely troublesome and therefore cannot be implemented for all welded products. In view of the above-mentioned problems, the present invention has been developed to effectively solve these problems. Therefore, its purpose is
To provide an automatic butt welding machine capable of automatically determining the quality of welding for all welded products at the end of welding.

[Means, Actions, and Effects for Solving the Problems] The automatic butt welding machine according to the present invention is constructed as follows in order to solve the problems of the prior art and achieve its objectives. That is, in the above conventional butt welding machine, a molten amount detection device detects the amount of molten metal from both opposing end surfaces of a pair of welded members by detecting the amount of movement of the movable electrode during welding;
A determining means is provided for determining whether or not the molten amount at the end of welding is appropriate by comparing the molten amount at the end of welding detected by the molten amount detection device with a preset reference molten amount. . According to the butt welding machine having the above configuration, during welding, the melt amount detection device always measures the melt amount from both opposing surfaces of the pair of welded members. At the end of welding, the determining means compares the current melting amount with the reference melting amount to determine whether the melting amount is appropriate. Therefore, according to the butt welding machine according to the present invention, the welding quality of all welded products can be automatically determined at the end of welding.

【Example】

Embodiments according to the present invention will be described below with reference to FIG. 1.2. FIG. 1 is a schematic diagram of a butt welding machine according to an embodiment of the present invention. The butt welding machine according to the present embodiment is operated and controlled by a control device 11, and one of the members to be welded 7 is held between the fixed electrodes 5, while the other member to be welded 8 is held between the movable electrodes 6, and the pressurizing device While pressing the movable electrode 6 in the direction of the fixed electrode 5 with the pneumatic cylinder 9 as
．． The opposing end surfaces 7a, 8a of 8 are butt welded. Each of the electrodes 5.6 is driven by a clamping device 10 such as a hydraulic cylinder or the like, and each of the welded members 7.8 is connected between the receiving portions 5a, 6a. It consists of drive parts 5b and 6b that sandwich the. Therefore, each electrode 5.6 is firmly clamped to each welded member 7.8 by the clamp device 10 so that each electrode 5.6 clamps each welded member 7.8. Further, the pair of electrodes 5.6 are connected to a power source 1 via the switch 2 and the transformer 3, thereby allowing the pair of electrodes 5.6 to be energized. This switch 2 is controlled by a control device 11 to open and close a circuit connecting a power source 1 and a pair of electrodes 5.6. The current flowing through this circuit is detected by a toroidal coil 19, and the detected value is displayed on a current display device 16. Further, the butt welding machine according to this embodiment includes a melt amount detection device 12, a melt amount display device 17, and a welding quality determination device 15 as a determination means. The molten amount detection device 12 detects the movement stroke of the molten amount detection arm 13 fixed to the movable electrode 6 during welding, thereby detecting the opposite end surfaces 7 of the pair of welded members 7.8.
a, 8 The amount of melting from a is detected. Further, the melt amount display device 17 digitally displays the melt amount detected by the melt amount detection device 12. The display value of the melt amount display device 17 is automatically set to zero by a signal from the control device 11, or
It is designed to be latched (held). Further, the welding quality determining device 15 includes the above-mentioned melt amount detecting device 1.
The appropriateness of the above melting amount at the end of welding is determined by comparing the above melting amount at the end of welding detected by step 2 with the upper and lower limit values of the appropriate melting reference amount set in advance. It is something. When the melt amount at the end of welding is outside the upper and lower limits, the operator is notified of the result by a warning means such as a buzzer or lamp. The butt welding machine according to this embodiment has a pair of members to be welded 7.
The receiver of each electrode 5.6 is connected between each member to be welded 7.8 between the portion 5a, 6a and the drive portion 5b, 6b so as to join the opposing end surfaces 7a, 8a of the electrode 5.8 to each other. After positioning the control device 1, for example, as shown in FIG.
1 and operates as follows. In addition, the appropriate upper and lower limits of the amount of melting from both opposing end surfaces 7a, 8a of the pair of workpieces 7.8 at the end of welding are measured in advance by, for example, a tensile test,
The upper limit value and lower limit value are set in the welding quality determination device 15 in advance. The operation procedure of the automatic butt welding machine having the above configuration will be explained below according to the flowchart shown in FIG. First, when the start switch 18 starts the operation, in step S2, the control device 11 sends the clamp device 1
A drive start signal is input to the terminal 0, and the clamp device 10 is driven. As a result, the drive section 5bJ of each electrode 5.6
b is connected to the receiving portions 5 a and 6 through each welded member 7.8.
As a result of pressing a, each member to be welded 7.8 is connected to each electrode 5.6.
It is firmly clamped. Next, after a predetermined period of time has elapsed since the clamp device 10 started to be driven, in step S2, a drive start signal is input from the control device 11 to the pneumatic cylinder 9, and the pneumatic cylinder 9 is driven. As a result, the movable electrode 6 is pressed closer to the fixed electrode 5, and both opposing end surfaces 7a of the pair of welded members 7.8
, 8 a are brought into pressure contact with each other. Next, after a predetermined period of time has elapsed since the pneumatic cylinder 9 started to be driven, in step S3, the circuit close signal is inputted from the control device 11 to the switch 2, and current is turned on between the pair of electrodes 5 and 6. Begins. Also, in sync with that,
In step S7, a zero set signal is input from the control device 11 to the melt amount display device 17, and the display value of the melt amount display device 17 is set to zero. After the start of energization, in step S8, the melt amount detection device 1
2, the amount of movement of the movable electrode 6, that is, the amount of melting from both opposing end surfaces 7m, 8a of the pair of members to be welded 7.8 is detected, and the value is displayed on the melting amount display device 17. Note that the current passing through the above circuit is the toroidal coil 19.
and its value is displayed on the current display device 16. Thereafter, after a predetermined period of time has elapsed from the start of energization, in step S4, the control device 11 inputs an open signal for the circuit to the switch 2, and the energization between the pair of electrodes 5.6 is terminated. This completes the welding of the pair of welded members 7.8. Next, a predetermined time after the end of the energization, a reverse drive start signal is input from the control device 11 to the pneumatic cylinder 9, and the pneumatic cylinder 9 is caused to start reverse drive. This results in
The pressure of the movable electrode 6 against the fixed electrode 5 is released. In addition, in synchronization with this, a display value latch signal is input from the control device 11 to the melt amount display device 17, and both opposing end surfaces 7a of the pair of welded members 7.8 after the end of energization, that is, after the end of welding. , 8 a, the melt amount from the melt amount display device 17 is latched. Further, almost simultaneously with step S5, in step S6, a reverse drive start signal is input from the control device 11 to the clamp device 1O, and the clamp device 10 is caused to start reverse drive. As a result, the clamping of each electrode 5.6 to each member to be welded 7.8 is released. In parallel with this, in step S2O, the display value latched in step S9 is input from the melt amount display device 117 to the welding quality determination device 15, and this latched value and the melt amount at the end of welding are inputted to the welding quality determination device 15. The welding quality is determined by comparing the standard upper limit value and lower limit value. As a result, if the latched display value is outside the upper and lower limits, the operator is notified of this using a lamp, buzzer, or the like. Therefore, if a defective weld product is found, the operator can easily recognize it. This completes the operation of the automatic butt welding machine according to this embodiment. Therefore, according to the automatic butt welding machine according to the present embodiment, it is possible to automatically and accurately determine the quality of welding for all welded products. Further, in this embodiment, since the melt amount is latched in the melt amount display device 17, if a defective weld product is produced, the operator can easily know the cause of the defect. Further, the automatic butt welding machine according to this embodiment is manufactured by adding various known devices to a conventional automatic butt welding machine, and therefore can be manufactured at low cost. In addition, in the above-mentioned embodiment, after the end of energization, step S
Step S is to latch the melting amount value in step 9.
Although C2 is performed in synchronization with the release of the pressurization in step S6, it may be performed in synchronization with the release of the clamp in step S6. Further, in the above embodiment, steps 87 to 810
The series of operation steps are started in synchronization with the start of energization in step S3, but they can be started at any time after the start of driving the pneumatic cylinder 9 in step S2 and immediately before or after the start of energization in step S3. It is also possible to do so. In the above-described embodiment, in order to zero-set the melt amount display device 17 in step S7, a zero set signal is input from the control device 11 to the melt amount display device 17 in synchronization with the start of energization in step S4. I tried to do it, but
When the toroidal coil 19 detects that a current has started flowing through the circuit and its value is displayed on the current display device 16, a zero set signal is input from the current display device 16 to the melt amount display device 17. You can do it like this.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an automatic butt welding machine according to an embodiment of the present invention, and FIG. 2 is a flowchart showing an example of control by the control device of the automatic butt welding machine. ! ...Power supply, 2...Switch, 3...Transformer, 5
. . . Fixed electrode, 6 . clamping device,
DESCRIPTION OF SYMBOLS 11... Control device, 12... Melt amount detection device, 13... Melt amount detection arm, 15... Judgment means (welding quality judgment device), 16...
Current display device, 17... Melt amount display device, 5i-st
o...operation step.

Claims (1)

[Claims] (1) One member to be welded (7) is held by a fixed electrode (5), while the other member to be welded (8) is held by a movable electrode (6), and the movable electrode ( 6) in the direction of the fixed electrode (5), both members to be welded (7, 8)
) in an automatic butt welding machine that butt-welds opposing end surfaces (7a, 8a) of the pair of members to be welded (7, 8) by detecting the amount of movement of the movable electrode (6) during welding. Opposite end face (
Melt amount detection device (7a, 8a) that detects the amount of melt from
12), the melting amount at the end of welding detected by the melting amount detection device (12), and a preset reference melting amount to determine whether the melting amount at the end of welding is appropriate. An automatic butt welding machine characterized by comprising: determination means (15) for determining.