TW471987B - Spot welding quality monitoring device and its method - Google Patents

Abstract

The present invention discloses a device for monitoring the spot welding quality and its method. The device and method first convert the analog current signal and analog voltage signal measured by the two electrodes of the spot welding system into digital data, and then process the two digital data by Hilbert transform to obtain their complex data, respectively. Finally, the complex voltage value is divided by complex current value to obtain the impedance Zin. By comparing the impedance Zin of the present invention with the existed data, the welding quality of welding spots is diagnosed.

Description

4 / 丄 兕 /

Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs

V. Description of the Invention (I) [Field of the Invention] The present invention relates to a device and method for monitoring the quality of spot welding, especially a device suitable for the automotive industry, machinery and equipment, aerospace industry, or other sheet metal parts. Welding manufacturing and other spot welding quality monitoring and diagnosis and methods in I industry. [Background of the Invention] Resistance Spot Welding (RSW) is a method of welding overlapping sheet metal parts by using the inherent resistance of the sheet metal workpiece itself and passing in an electric current. Resistance welding involves electrical, thermal, mechanical: metallurgical and surface interactions. Since this technology does not require other metal fillers, and only affects the characteristics of this point, it has been widely used in metal joining processes, such as automobiles, machinery and equipment, and aerospace industry. The spear 6 is a typical welding process. As shown in the figure, during the squeezing time, the upper electrode exerts a certain pressure on the workpiece, and the workpiece is placed on the lower electrode and can be fixed by the worker or fixture; During the welding time, a preset current flows through the two electrodes and the workpiece to soften and melt the material of the workpiece; during the holding time, the current is turned off and the workpiece is continuously subjected to a certain pressure from the two electrodes. The pressurization effect promotes the gradual solidification and solidification of the welded part, and at the same time it can have a forging (f 0rg 1 ng) effect to improve the mechanical properties. At the end, the upper electrode is removed and the next spot welding operation is prepared. The best known solder joint detection method is achieved by measuring the secondary resistance as shown in Figure 7, which is to divide the voltage peak measured every half cycle by the half cycle. The so-called "dynamic resistance" obtained from the measured current peaks. However, since the measurement is calculated once every half cycle, the conventional testing method is only applicable to the national standard of the country (CNS> A4 specifications.) (2) 0 X 2_97 Love (please read the precautions on the back first) Fill out this page} i 1111 Ordered! 1111987 471987 A7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (2) There are two documents, which are too rough; and there is a time difference between the peaks and peaks At, Because of the following: voltage peaks and electric-approximate approximations; as for the voltage peaks, they are only green. Jade, Ai, such as, there is no Ji inventor. Because of this, the active invention can solve the above problems. Spot welding quality monitoring device: Emperor Ersi's research and experiments have finally completed this invention that benefited the world / 10,000 go. [Summary of the invention] The main purpose of the present invention is to provide a spot welding product and its method. The quality of a spot can be monitored and diagnosed in real time. Another purpose of the present invention is to provide a spot welding quality and method, which can be used for the production of intelligent welding spot diagnosis system use. ," In order to achieve the above purpose, the present invention mainly includes a device, a voltage measuring device, at least one analog to several processing units, and an output unit. The current measuring device and the voltage measuring device are The analog current signal and the analog voltage signal between the two electrodes of the spot welding system are measured separately in each frame; the measured analog current and voltage signals are converted into digital current and digital voltage by an analog bit converter. The micro-processing unit then calculates the impedance between the two electrodes of the spot welding system according to the following equation (Z j π).

Zin mm

Among them, I⑴ = i⑴ + jH (i (t)), JL k paper size applies Chinese National Standard (CNS) A4 specification (210 χ 297 mm) (Please read the precautions on the back before filling in this page) --- Order --------- Wei B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs V. Invention Description (3) ^ Pressed plural form (eGmplex), its imaginary part; Xi Zixi Hilbert transf (Hilbert transf_) ·· // 〇 (,)): = _L * v (〇〇 The electrical impedance calculated by the micro-processing unit is known by the output preamble. The output unit can be- A display device (displaying device) is used to display dry beer ':: 柷 (Zin) 値 or curve. ㈡ 则 平', ..., accounting for obstacles The present invention may further include a data analyzer as required. A comparison is made between the calculated data of the lightning resistance 7G 'and the existing data (i η) stored in the memory unit ^ Corruption, which is stored in advance in the memory unit's representative-solder joint welding process. Electrical impedance data, such as spot one bad solder joint, or -expulsion solder joint (expulsi0n)....新. Newly calculated resistance 'spot existing funds: After comparison, the comparison result can show the quality of the solder joint by any adapter, such as the J signal to indicate the newly calculated electrical impedance A) 値 and In addition, the intelligent micro-processing unit can also be used to diagnose non-messages, such as the curve data obtained by combining the welding of each welding point in the welding process.) Automatically diagnose good points, or save them automatically. 1 ratio of existing data in memory unit

Comparison; or through appropriate statistics or neural network recognition diagram (1L network pattern recognition srh one,. Scheme) and the calculated resistance

— — II I 9 Outfit --- II --- Order ----- ί · ^ ί (Please read the precautions on the back before filling this page)

This paper size applies the Chinese National Standard (CNS) A4 specification (210 χ 29 / each centimeter) A7 instructions (thousands) ~ 値 or curve comparison ’and then the output unit ㈣ plots the diagnostic results. ㈣ Invention exclusively by # Γ. The technology of the present invention is novel and indeed has an enhanced effect, so the application is made according to the law [Simplified description of the drawings] Figure 1 is a functional block diagram of the embodiment of the present invention; Figures 2 ^) and 2 (b) are calculated by the embodiment of the present invention. Resistance (curve and imaginary part graphs; Figure 3, Figure 3, Figure 2) This embodiment of the present invention uses another set of parameter inputs to calculate the real impedance curve of I 黾 impedance 値; Figure 4 is another example of the present invention. Functional block diagrams: Figure 5 is a real-part curve of an electrical impedance sample of a burst solder joint; Figure 6 is a typical resistance welding process; and Figure 7 shows the difference between voltage and current measured using conventional methods 4 (Please read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs [Illustration of the drawing number] Current meter 21 Analog of current to analog of digital converter voltage Digital Converter Micro Processing Unit 40 Data Analyzer 42 Indicator Display 51 Spot Welding System 80 Pressure Rod 83 Sheet Metal 9 1 > 9 2 Paper Standard Towel Standard (CNS) A4 Specification ⑵〇 × 297 each love Voltage measurement data processor display Membrane electrode starter 22 3 1 32 41 50 60 81, 82 84 t -------- Order --------- t Printed by the Employees ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs and 471987 A7 —___________ Β7 ______ V. Description of the invention (Γ) [Detailed description of the preferred embodiment] In order to allow your investigation committee to better understand the technical content of the present invention, it is particularly fortunate that the specific embodiment is described below. Please refer to Figure 1, The spot welding system 80, such as a spot-welding gUn, mainly includes a pressure rod 83 and an actuator 84 for activating the pressure rod 83. Current can flow through the two electrodes 8 1, 82 and the clamp The sheet metal parts 9 1, 92 are interposed, among which the electrode 8 1 is connected to the pressure sample 8 3. The current measuring device 21 and the voltage measuring device 22 can be measured separately at a predetermined time interval. Measure the current and voltage analog signals between the two electrodes 8 1, 8 2. In order to obtain further information, the measured analog signals then pass the current analog to digital converter 31 (A / D Converter) and the voltage analog to digital conversion. Device 3 2 to convert into digital current and digital voltage νΓΟ. Then convert the digital current and digital voltage The pressure ν (^ > is converted to its complex form in the microprocessing unit 40, which uses the formula: 1 ⑴ = i (t) + jH (i (t)), inverse V (t) = v ( t) + jH (v ⑴) where the imaginary part and the Hilbert transform representing digital current and digital voltage ν⑴ are derived from the following equation: nt 丹 (v (,)) =) * ν (ί) πί The Hilbert transform of the above digital current and digital voltage V (X) is a conversion formula of conventional electronics, and it also specifically means that the phase angle of the digital signal is converted to -90. . Among them, the real part of Zin This paper size is applicable to China National Standard (CNS) A4 specification (21 × X 297 mm) _ 丨 | 丨! !! — —! '· 1111111 alii — —— — — (Please read the notes on the back before filling this page) 471987 Z. m A7 V. Description of the invention (t) 2 Real resistance 値 U) Changes over time. After the digital = pressure 4⑽ is changed to the complex form, the electrical impedance (Z.) can be calculated by the micro processor single material processor 41 according to the following equation. Read m. Since the denominator / ⑺ is a complex form in the above formula, the calculated electricity The impedance (Zin) must be meaningful at any time interval, and in order to obtain more accurate results, the sampling frequency can also be relatively increased, that is, the time period can be shortened so that each cycle has a majority of sampling points. In addition, in order to avoid distortion of the current or voltage signals caused by higher hamonic components ("" ο "-, the above signals may be passed through a band-pass filter (band_pass to remove higher resonances to make them more dense). The Hilbert transform is entered in the main operation solution. Figures 2 (a) and 2 (b) show that the spot welding system 80 of this embodiment is at a constant pressure of 150Kpa, a current of 4,200A, and the spot welding time is In 0.4 seconds, the real and imaginary curve of the electrical impedance obtained by the above two calculations can be used to describe the behavior of monitoring the spot welding system 80. For example, the real part of Figure 2 (a) In the curve, the resistance of the zheng is reduced at the beginning of welding. It shows that the valve surfaces of the sheet metal parts 91 and 9 are in good contact, and the sheet metal parts 9 丨 and 92 start to weld due to the heat generated during the resistance. The sheet metal parts 9 1, 9 2 have risen to a considerable degree of bonding. After that, the 'welding (we 1 dingnugget) is gradually turned into the best shape, and the electrical impedance increases slightly linearly and reaches a peak. From peak to At the end of welding, the electrical impedance gradually decreases and becomes sawtooth Figure 3 shows the actual size of the electrical impedance calculated from another set of parameters. The paper size is over the Chinese national standard (CNS> A4 specification (21〇x 297mm f)) ------- ----; ----- 'installation -------- order --------- line (please read the precautions on the back before filling this page) Intellectual Property Bureau of the Ministry of Economic Affairs Printed by employee consumer cooperative A7 V. Description of invention (7) At f force 12, such as current 6,500 ° A, and welding time 0.4, lower U 'as shown' at the bottom (point B) and Xin Yi ( The electrical impedance decreases, showing that the burst has generated a burst. 'The calculated electrical impedance Zi „is displayed via a display 50, such as a display screen = display, showing a number or as shown in Figure 2 (a), 2 (b). Or FIG. 3 and FIG. 4 are functional block diagrams of another embodiment, one of which includes a data processor 41 and a data analyzer ο, and a parallel connection: connection. The data analyzer 42 can compare resistance 仏^ Lttr—Existing data of the group. The existing data is stored in advance. I :::: can be entered manually by others. “Representative-good impedance data for welding” or poor welding or burst welding joints are stored in the record sheet. B two Square < resistance time and intensity, can be pre-stored in the 4 h60, above the calculated once, immediately use the information analyzer 42 compares the newly calculated sum ^;

Zln 値 and the 6G that has been stored in the memory unit = ^ New soldering% 乏 口 口, 〒brothers are greedy, so as to judge: ~ quality. When it matches the existing data, the indicator light shows lipstick, green, and yellow LEDs, which can immediately display the new: What kind of quality is the point. Since the method of the present invention only needs: two of the above three types of welding calculations, the operator can take any response measures according to the measurement and calculation in real time. 、 -Quality display results inconclusive or: For example: ΓΓ type micro processing unit 4 ° to diagnose abnormality. The connection process can successively reduce the electrical impedance of each point (or (Please read the precautions on the back before (Fill in this page) I --- Ί ..-- Order !!!!! --- Consumer cooperation with employees of the Intellectual Property Bureau of the Ministry of Economic Affairs, printed ^ sheets in a timely manner (plus 297 471987 A7 V. Description of the invention (A) The combined curve data) Automatically diagnoses good solder joints or bad solder joints and automatically stores them in the memory unit 60 as existing data-for later reading for comparison 'or through appropriate (statistical or neural The network recognition pattern (_ral network pattern recognition scheme) is compared with the calculated impedance or curve, and then the diagnosis result of the graph is output by the output unit. Furthermore, the impedance obtained by the method of the present invention can be passed immediately. Analyze the statistics and input them to the automatic feeder to directly control the preparation of the point material. In this way, the operating parameters of the point device 80 can be corrected in real time, and it can also be used to evaluate the productivhy and quality of the point device 80. Based on the above, the present Regardless of the purpose, means, and effect, it shows its characteristics that are quite different from the conventional technology. It is a major breakthrough in "point quality monitoring devices and their methods. For the benefit society, it ’s a real sense. But it should be noted that many of the above embodiments are just examples for the convenience of explanation. The scope of the claims of the present invention should be based on the scope of the patent application, not limited to The above example (Please read the precautions on the back before filling out this page) -------- Order --------- Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs

Claims (1)

4/1987 098800 ABCD Consumers ’cooperation with the Intellectual Property Bureau of the Ministry of Economic Affairs, Du printed, final quality monitoring device, which can be used to monitor-welding of spot welding equipment, 7, the spot welding equipment includes two electrodes; of which, the device includes at least: A measuring device for measuring an analog current signal between the two electrodes; A voltage measuring device is used to measure the analog voltage signal between the two electrodes. To V analog to digital converters are used to convert the measured analog cement signal into a digital current and / or convert the The measured analog voltage signal becomes a digital electric voltage v; a micro-processing unit used to calculate the electrical impedance between the two electrodes of the spot welding equipment according to the following equation (zij: 7 .mmm 5 where, I⑴ = [⑴ Seven jH (i (t)), ι is the plural form of the digital voltage v, which has an imaginary part. Υ ^ Υν is transmitted from the Hilbert transform: 好 (v (,)) =丄 * ν (ί), nt the ί) is the plural form of the digital current Γ Γ0, 1 of which has an imaginary part // 0 is derived from Hilbert transform: _)) = 丄 * 办) πί; and an output unit for outputting the electrical impedance (Zin) calculated by the secret processing unit ° This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 order binding ----- ---- Line (please read the precautions on the back before filling this page) 6. The scope of patent application A8 B8 C8 DS Printed by a member of the Intellectual Property Bureau and Consumer Cooperatives 2 • The device described in item 1 of the scope of patent application, which further includes a data analyzer and a memory unit, the data analyzer is used to compare the resistance k (Z i η) with Existing data stored in the memory unit, the existing data is. Information about various welding qualities. The device described in item 2 of the patent scope, wherein the existing data is the electrical impedance data about a burst solder joint. The device described in item 2 of Shen's patent scope further includes a display 'for displaying the comparison between the electrical impedance (Zin) and the existing data Yin Guo. 5 · As described in item 1 of Shen's patent scope Device, wherein the output unit further includes a display screen for displaying the electrical impedance (Zb) .: A method for monitoring the quality of spot welding, which can be used to monitor the welding quality of spot welding equipment, which includes two electrodes; The method includes at least the following steps: (a) Measure the analog current signal and analog voltage signal between the two electrode pairs of the spot welding equipment, and convert them into digital current and digital electricity, respectively. vf .; (b) Calculate the electrical impedance (Zin) between the two electrodes of the spot welding equipment with the following equation: z = m, 丨 m I (t) 5 0, where P⑺ = v⑴⑺), which is the lowest among the digital voltages of children. The plural form, which has an imaginary value, is derived from the Hilbert transform: 6. τύ! Ν (〇ι_ This is the plural form of the digital current, which has a paper scale applicable China National Standard (CNS) A4 Specification ⑽ x 297 -------- (Please read the notes on the back before filling in this page) Eq. (Hilbert transform). V and touch = furnace (0 (c) to output the electrical impedance (zin). Special: The method described in item 6 of the scope further includes a step ⑷: Compare the electrical impedance (Zin) with: ('The existing information is about various welding qualities: please refer to the method described in item 7 The second series is about the electrical impedance data of a burst solder joint. A is the existing impoverishment. • The method mentioned in the patent application 7 item includes-step ⑷: display the resistance; compare the results after step 。. (Zin) and The paper size of the existing data is in accordance with China National Standard (CNS) A4 (210 X 297 male father)