JPH05228647A - Quality judging device of resistance welding - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a resistance welding quality judgment device capable of outputting a quality judgment result in a short time. [Structure] Physical quantities such as welding current, inter-electrode voltage, inter-electrode displacement, etc. are detected by the detection unit 1, and a memory circuit 3 stores a calculation result table of numerical calculations required when performing numerical analysis based on a heat conduction model. The calculation unit 2 uses the physical quantity detected by the detection unit 1 and the calculation result table stored in the storage circuit 3 to perform a numerical analysis of the temperature distribution and the energized diameter based on the heat conduction model, and the output unit 4 It has a configuration for outputting a temperature distribution, an energized diameter, a calculated nugget diameter, or a comparison result of the calculated nugget diameter and a set value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding quality judgment apparatus by numerical calculation processing.

[0002]

2. Description of the Related Art Conventionally, as a nondestructive quality judgment method in resistance welding, welding current, interelectrode voltage or interelectrode displacement, etc. are detected and the detected physical quantity is compared with a model waveform to judge welding quality. Monitoring systems were common. However, in these conventional monitoring systems, it is necessary to perform pre-welding at the production site for each material to be welded and determine the relationship between the physical quantity to be detected and the welding quality in advance, and the welding quality is correlated with the physical quantity. However, there is a problem that the accuracy is low because it is estimated by.

In order to solve this problem, a numerical calculation simulator has been developed which measures the welding current and the welding voltage, numerically calculates the temperature distribution and the current-carrying diameter based on the heat conduction model, and estimates the nugget diameter. (Reference: Welding Society of Japan, Resistance Welding Research Committee: “Resistance Welding Phenomenon and Its Application (I)”, Japan Welding Society, (Showa 57), p. 12
~ P. 52).

[0004]

However, in the above-mentioned conventional method, the numerical calculation simulator is constituted by complicated numerical calculation, and it takes a long calculation time to obtain the result. Therefore, after the welding is completed, it takes about 10 to 20 minutes to output the result. The present invention solves the above-mentioned conventional problems, and an object thereof is to speed up a numerical calculation simulator and to provide at low cost a resistance welding quality judging device capable of outputting a quality judgment result in a short time after welding is completed. .

[0005]

To achieve the above object, the present invention provides an approximate calculation result table in which a part or all of the temperature distribution calculation and the energization diameter calculation by a numerical calculation simulator are stored in a storage circuit. It has a configuration to be replaced by.

[0006]

According to the present invention, with the above configuration, the temperature distribution calculation and the energization diameter calculation based on the heat conduction model are performed at high speed, and as a result, the determination result can be output in a short time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. Welding electrodes 6 sandwiching the material 8 to be welded
And resistance welding power source 5 through 7. Physical quantities such as welding current, inter-electrode voltage, inter-electrode displacement, etc. are detected using the detection unit 1. The calculation unit 2 carries out a numerical analysis of the temperature distribution and the current-carrying diameter based on the heat conduction model. The storage circuit 3 stores a calculation result of a numerical calculation required when performing a numerical analysis. The output part 4 has a temperature distribution, an energization diameter,
The calculated nugget diameter or the comparison result of the calculated nugget diameter and the installation value is output.

The operation of the above embodiment will be described. Welding is performed by the welding power source 5, and the welding current, the inter-electrode voltage, the inter-electrode displacement, etc. detected by the detection unit 1 are input to the calculation unit 2 and the operation shown in FIG. Numerical analysis is performed as follows in accordance with the flowchart of FIG. Enter the initial temperature distribution and determine the specific resistance of each part. The energizing diameter is calculated using the resistance value that can be calculated from the detected welding current and the inter-electrode voltage and the specific resistance value of each part. The calorific value of each part is calculated from the welding current and added to the initial temperature to calculate a new temperature distribution. Determine the specific resistance of each part according to the new temperature distribution. If the number of repetitions has not reached the number of times corresponding to the welding time, the process is repeated again. Completion of calculation In the above numerical analysis, for some or all of the numerical calculations for which the relationship between the variables and the calculation results can be predicted in advance, such as the numerical calculations using the heat conduction equation performed when obtaining a new temperature distribution of , Based on the approximate calculation result table stored in the storage circuit 3, the result is input without performing the numerical calculation. As a result of such a numerical analysis, the obtained temperature distribution, current-carrying diameter or nugget diameter (melted portion) is input to the output unit 4 and output as shown in FIG.

As described above, according to this embodiment, since the storage circuit is provided in the numerical calculation simulator and a part or all of the numerical calculation part is changed to the processing using the approximate calculation result table, it has been 10 minutes or more until now. The required calculation time was reduced to less than 1 second.

[0011]

As is apparent from the above embodiments, according to the present invention, a memory circuit is added to a quality judgment device for performing numerical calculation simulation, and the numerical calculation part is changed to a process using an approximate calculation result table. Therefore, it is possible to inexpensively provide a resistance welding quality determination device that speeds up the numerical calculation and outputs the determination result in a short time after the completion of welding.

[Brief description of drawings]

FIG. 1 is a block diagram of a resistance welding quality determination apparatus according to the present invention.

FIG. 2 is a flowchart of a numerical analysis simulator incorporated in the arithmetic unit of the present invention.

FIG. 3 is a graph showing an output example of a numerical calculation simulator according to the present invention.

[Explanation of symbols]

 1 detection unit 2 calculation unit 3 storage circuit 4 output unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Ihara 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A detection unit including means for directly or indirectly measuring current between welding electrodes of a resistance welding machine, means for measuring voltage between welding electrodes, or means for measuring displacement between electrodes, and In the electrode of the resistance welding machine and the material to be welded, the temperature distribution calculation based on the heat conduction model and the storage circuit for storing an approximate calculation result table of a part or all of the numerical calculation of the energization diameter calculation, and detection by the detection unit Using the calculated physical quantity and the calculation result table stored in the storage circuit, a numerical calculation simulator for calculating the temperature distribution and the current-carrying diameter based on the heat conduction model and estimating the nugget diameter from the temperature distribution is provided. Resistance welding provided with a calculation unit having the same, and an output unit for outputting a result of comparison between a temperature distribution processed by the calculation unit, a nugget diameter, or a nugget diameter and a set value. Quality determination device.