KR101739941B1 - Control method of spot welder and recording medium for storing program thereof - Google Patents

Control method of spot welder and recording medium for storing program thereof Download PDF

Info

Publication number
KR101739941B1
KR101739941B1 KR1020150099954A KR20150099954A KR101739941B1 KR 101739941 B1 KR101739941 B1 KR 101739941B1 KR 1020150099954 A KR1020150099954 A KR 1020150099954A KR 20150099954 A KR20150099954 A KR 20150099954A KR 101739941 B1 KR101739941 B1 KR 101739941B1
Authority
KR
South Korea
Prior art keywords
current
peak
time
resistance
welding
Prior art date
Application number
KR1020150099954A
Other languages
Korean (ko)
Other versions
KR20170008592A (en
Inventor
강문진
김동철
김철희
유회수
김영민
황인성
Original Assignee
한국생산기술연구원
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 한국생산기술연구원 filed Critical 한국생산기술연구원
Priority to KR1020150099954A priority Critical patent/KR101739941B1/en
Priority to PCT/KR2016/007551 priority patent/WO2017010787A1/en
Publication of KR20170008592A publication Critical patent/KR20170008592A/en
Application granted granted Critical
Publication of KR101739941B1 publication Critical patent/KR101739941B1/en

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/10—Spot welding; Stitch welding
    • B23K11/11—Spot welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/24—Electric supply or control circuits therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/24—Electric supply or control circuits therefor
    • B23K11/25—Monitoring devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/24—Electric supply or control circuits therefor
    • B23K11/25—Monitoring devices
    • B23K11/252—Monitoring devices using digital means
    • B23K11/257—Monitoring devices using digital means the measured parameter being an electrical current
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/36—Auxiliary equipment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/36—Auxiliary equipment
    • B23K11/362—Contact means for supplying welding current to the electrodes

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Resistance Welding (AREA)

Abstract

The present invention relates to a control method of a spot welder capable of minimizing an unnecessary amount of heat and preventing welding defects due to unnecessary heat and damage of a welding material and a recording medium on which the program is stored. Applying the current gradually increasing; Detecting a peak copper resistance (R peak ) of the weld material while applying the current gradually increasing; Reducing the current applied to the welding material for a predetermined period of time after recovering the peak dynamic resistance (R peak ); And applying a gradually decreasing current to the weld after the recovering step.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a spot welding machine,

TECHNICAL FIELD The present invention relates to a spot welding technique, and more particularly, to a control method of a spot welder and a recording medium on which the program is stored.

Generally, spot welding is a welding method belonging to electric resistance welding, and refers to a method of welding while applying pressure using heat generated when a current flows through the metal.

Spot welding is a process in which two metals to be bonded are put together and current is applied while applying appropriate mechanical pressure, and heat of resistance is generated, thereby utilizing the property of bonding the pressure parts. Such spot welding is a very common welding method for assembling a car body.

An apparatus for resistance spot welding includes a fixed lower electrode and an upper electrode that moves up and down on the lower electrode. Therefore, the welding material is seated on the lower electrode, and welding is performed by movement of the upper electrode.

1. Korean Patent Publication No. 2012-0032119 (2012.04.05) 2. Korean Patent Publication No. 2012-0001239 (2012.04.04)

However, such conventional spot welding has a problem that the welding result is uneven due to various factors such as the surface condition of the joint portion, the position of the welding spot, the number of the spotting points, etc., and the welding defect and the welding material are damaged due to the unnecessary heat.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a control method of a spot welder capable of minimizing an unnecessary heat quantity and preventing welding defects due to unnecessary heat, And to provide a recorded recording medium. However, these problems are exemplary and do not limit the scope of the present invention.

According to an aspect of the present invention, there is provided a method of controlling a spot welder, the method comprising: applying a current to the welding material while gradually increasing current through at least one electrode; Detecting a peak copper resistance (R peak ) of the weld material while applying the current gradually increasing; Reducing the current applied to the welding material for a predetermined period of time after recovering the peak dynamic resistance (R peak ); And applying a gradually decreasing current to the weld after the recovering step.

The method may further include the step of applying a current having a magnitude set in the welding material constantly for a predetermined time before the step of gradually increasing and applying the current.

The step of reducing and recovering the current applied to the welding material for a predetermined time may include turning off the current applied to the welding material for the set time.

The step of reducing and recovering the current applied to the welding material for a predetermined period of time may make the current applied to the welding material correspond to 100% of the preset reference current at the completion of the recovery. In this case, the time from when the current is applied to start the welding to when the peak resistance (R peak ) appears may be more than 30 ms.

Or reducing the current applied to the welding material for a predetermined period of time may allow the current applied to the welding material to have a value smaller than a preset reference current at the completion of the recovery. In this case, the time from when the current is applied to start the welding to when the peak dynamic resistance (R peak ) appears may be 30 ms or less.

Wherein the set time is 1ms to 10ms when the detection time of the peak copper resistance (R peak ) is 30m or less, and the peak copper resistance R peak ) may be 10 ms to 20 ms when the detection time exceeds 30 ms.

The step of detecting the peak dynamic resistance (R peak ) comprises: measuring the resistance of the weld material n times at intervals of t 1 ; And detecting the maximum resistance among the measurement resistances of the weld material as the peak copper resistance (R peak ).

The step of detecting the peak dynamic resistance (R peak ) comprises: measuring the resistance of the weld material n times at intervals of t 1 ; It may include a; and the detection of the peak the same resistance (R peak), comprising: a resistance material the weld measurement repeated n times a period of t 1 on the basis of the n x-th from the n x-th of the n times, .

The step of repeatedly measuring the resistance of the weld material may be repeatedly performed a predetermined number of times, such that when a new peak dynamic resistance is detected, it is updated to the peak dynamic resistance (R peak ).

The step of detecting the peak dynamic resistance (R peak ) may be performed within a maximum allowable resistance or within a maximum allowable current applied to the weld material.

According to another aspect of the present invention, there is provided a recording medium on which a program for performing the control method of the spot welder described above is stored.

According to the embodiment of the present invention as described above, it is possible to minimize unnecessary heat, prevent welding defects due to unnecessary heat and damage of the welding material, increase the lower limit of the current with the required tensile strength, It is possible to have a wide region of the welding region, to make the welding region favorable to a nugget having a desired size, and to prevent the welding at the time of welding. Of course, the scope of the present invention is not limited by these effects.

1 is a flowchart showing a control method of a spot welder according to an embodiment of the present invention.
FIG. 2 is a configuration diagram showing a welding machine according to an embodiment of the present invention.
3 to 5 are graphs showing a hysteresis curve of an applied current with respect to time according to an embodiment of the present invention.
6 and 7 are flow charts showing steps of measuring peak copper resistance in a method of controlling a spot welder according to an embodiment of the present invention.
8 is a graph showing current, voltage, and dynamic resistance waveforms according to an example of a method of controlling a spot welder according to the present invention.
9 is a photograph of a welded fracture section of a specimen welded by the method of controlling the spot welder according to the embodiments of the present invention.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are described in order to more fully explain the present invention to those skilled in the art, and the following embodiments may be modified into various other forms, The present invention is not limited to the embodiment. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the invention to those skilled in the art. In the drawings, the thickness and size of each layer are exaggerated for convenience and clarity of explanation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings schematically showing ideal embodiments of the present invention. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention should not be construed as limited to the particular shapes of the regions shown herein, but should include, for example, changes in shape resulting from manufacturing.

FIG. 1 is a flowchart illustrating a method of controlling a spot welder according to an embodiment of the present invention, and FIG. 2 is a configuration diagram illustrating a welding machine according to an embodiment of the present invention. FIGS. 3 to 5 are graphs showing the history of the applied current over time to explain the method of controlling the spot welder according to the embodiments of the present invention. FIG.

1 to 5, a method of controlling a spot welder according to an embodiment of the present invention includes steps of applying a current to a welding material while increasing current, detecting a peak resistance (R peak ) (S14). After detecting the peak dynamic resistance (R peak ), a step S15 of reducing and recovering the current applied to the welding material for a predetermined period of time and a step S16 of applying the welding material while decreasing the current are performed .

Before the step S13 of applying the welding material while increasing the current, step S11 of preparing the welding material and step S12 of applying the current constantly may be performed.

According to the step S11 of preparing the welding material, at least one welding material 10 for spot welding is prepared and the welding material 10 is placed on at least one electrode 20. [ At this time, for example, the welding members 10 may be positioned between the upper and lower electrodes 20 as a pair.

When the welding material (10) is prepared, a current is applied to the welding material (10) through the electrode (20). In the conventional general spot welding method, a current having a specific value is constantly applied during the welding time, but the current is applied in various stages during the welding.

3 to 5, at the initial stage of welding, a predetermined amount of the reference current, for example, a current corresponding to about 80% of the reference current 8 kA, is constantly applied to the welding material 10 for a predetermined time (S12). The constant holding step S12 of this current may correspond to the adaptive control type and may include raising the current to keep the current constant.

In the present specification and claims, the reference current means a predetermined current so as to be a reference of the fraction of the current applied to the weld material. For example, if the reference current is 8 kA, the current set at 80% of the reference current means 6.4 kA. The reference current may refer to a DC current that is constantly applied during a conventional welding process in a conventional spot welding process. For example, FIG. 3 shows a pattern (a normal DC current pattern) in which a reference current is constantly applied during a welding time as a conventional general method of viscous connection.

In the predetermined maintenance phase of the current (S12) may be detected at least the same resistance (R min), at least the same resistance (R min) is a predetermined time interval (t 2), for example, copper for the welding material 10 in a 5ms interval By measuring the resistance, the minimum value by the dynamic resistance measurement is obtained. This can be obtained from the current applied to the welding material 10 by the power supply control unit 30 and the same or similar method as the methods of detecting the peak copper resistance R peak will be described with the exception of minimum value extraction and time interval Can be used.

The time interval t 2 for measuring the minimum dynamic resistance R min in this embodiment is set different from the time interval t 1 for measuring the peak dynamic resistance R peak , The time intervals may be set to be the same. The time from the application of the current through the electrode 20 to the welding material 10 to the end point of the constant current holding step S12 may be 20 ms as an initial current time t in .

The application of the electric current to the electrode 20 can be performed under the control of the power supply control unit 30, and the power supply control unit 30 can control the operation of the spot welding machine according to a predetermined process, The application of the electric current to the electrode 20 can be controlled. The power control unit 30 may be used not only to supply power to the spot welder shown in FIG. 3 but also to measure the resistance of the weld material 10, the minimum dynamic resistance Rmin and the peak dynamic resistance Rpeak , And can control the calculation, the application and off of the current, and the like, and can have a timer for time control.

The current is constantly applied to the welding material 10 for a predetermined time and then the welding material 10 is applied to the welding material 10 by gradually increasing the current through the at least one electrode 20 under the control of the power control unit 30 S13). In this step S13, the current value at the gradually increasing time point of the current, that is, the minimum current value i upmin may be, for example, 80% of the reference current and the current value of the gradual increase end point of the current, upmax may be 120% of the reference current, for example, and the up current time t up may be performed for 30 ms, for example.

The peak dynamic resistance (R peak ) of the weld material 10 is detected using the current applied to the weld material 10 (S14) in a step S13 of applying the current to the weld material 10 while increasing the current (S14) . Here, the peak dynamic resistance (R peak ) may be detected by the power supply control unit 30 and may be a peak among the measurement resistances for the weld material 10. [ Here, the measurement resistance of the welding material 10 can be calculated from the voltage at both ends of the welding material 10 and the current applied to the electrode 20 by the power supply control unit 30. When the power is constant, 20 and the like. Also, the peak dynamic resistance (R peak ) may vary depending on the type and thickness of the weld material 10 and the like.

The step S14 of detecting the peak dynamic resistance (R peak ) can be performed within the maximum allowable resistance or within the maximum allowable current applied to the weld material 10. Peak copper resistance (R peak), step (S14) for detecting is there is carried out by a resistance measurement of the weld material 10, such a measure increases the current applied to the electrode 20 to the welding material 10 is gradually . Therefore, when the gradual increase of the current is not limited for reasons such as the inability to detect the peak dynamic resistance (R peak ), an excessive current is applied to the electrode 20, which may lead to welding defect and safety problem. In order to solve this problem, resistance measurement of the welding material 10 may be performed within a predetermined maximum allowable resistance, or may be applied so that the current gradually increases in the welding material 10 within a predetermined maximum allowable current.

After detecting the peak dynamic resistance (R peak ), the current applied to the welding material 10 is reduced and restored during the set time t r (S15) (S15). The counting of the set time t r and the control of the current can be performed in accordance with the process set by the power supply control unit 30. The power supply control unit 30 uses the timer to measure the set time t r , A count of time can be performed.

The step of reducing and recovering this current includes the step of maintaining the current applied to the weld material 10 as shown in Figures 3 and 4 such that a low current i low is applied during the set time t r . Low current applied for a set time (t r) (i low) has a value lower than the set time (t r), a current (the starting current, i upmax) applied to the weld 10 at the time the start Means that. This step may be a step of abruptly reducing or even stopping the amount of heat applied to the welding material 10 for a short period of time. In this sense, the above-mentioned "Quot; can be referred to as " idle time ".

At this time, the current i low applied during the set time t r , that is, the dwell time t r , can be kept constant as shown in FIGS. 3 and 4. However, the low current (i low ) does not have to be constant and may have various forms ranging from a low level to a start current (i upmax ) during a rest time (t r ).

As another example, the step of reducing and restoring the current as shown in FIG. 5 may be a step of turning off the current applied to the weld material 10 for a predetermined resting time t off . In this case, no current is applied during the rest time t off .

The effect of cooling the welding material for a short time is generated by keeping the current value lowered to the low value during the resting time (t r , t off ), or turning off the current and then recovering it again. If the amount of current applied to the welding material is excessive, the amount of heat input to the welding eventually increases, and the quality of the welding may be reduced due to the generation of spatter due to the excessive amount of heat input. In the present invention, in order to prevent an excessive amount of heat input after detection of the peak dynamic resistance (R peak ), a current value injected for a short period of time may be reduced to achieve a welding material cooling effect according to a reduction of a heat input amount.

The current at the completion of the recovery (hereinafter referred to as recovery current, i dn1 ) may have the same or lower value compared to the reference current. For example, as shown in FIG. 3, the recovery current (i dn1 ) may have a value corresponding to 100% of the reference current. As another example, the recovery current i dn1 may have a value corresponding to 80% of the reference current, as shown in Fig.

The level of this recovery current (i dn1 ) can be controlled in conjunction with the detection time of the peak copper resistance (R peak ). As shown in FIG. 4, peak copper resistance (R peak) detection time (t p), i.e. (R peak) peaks such resistance from the applied time of the electric current to the welding start is less than the time the time until a predetermined time shown in, For example, when the peak is less than 30 ms, the peak dynamic resistance (R peak ) is detected in a relatively short time after welding, which corresponds to a case where the input heat amount is high at the beginning of welding. In this case, problems such as generation of spatter due to excessive heat input in the process subsequent to the initial welding process due to the amount of heat accumulated in the welding material may occur. In this case, the recovery current (i dn1 ) is recovered to a value smaller than the reference current, for example, 80% of the reference current, and then the operation is performed to control the amount of heat input as a whole have. As another example, the peak dynamic resistance (R peak) detection time (t p) is a predetermined time-out, as an example, when 30ms excess is returned to be equal to 100% of the relative to the recovery current (i dn1) the current value of .

The dwell time (t r , t off ) may be from 1 to 20 ms, and may be, for example, 5 ms. If the downtime (t off ) is less than 1 ms, the cooling effect is insignificant. If the downtime (t off ) is more than 20 ms, the welding may not proceed effectively due to excessive cooling. On the other hand, this dwell time can be controlled in conjunction with the detection time of the peak dynamic resistance (R peak ). As shown in FIG. 3, the dwell time when the detection time t p of the peak dynamic resistance (R peak ) is equal to or less than the predetermined time may be the same or smaller than that when the detection time t p is greater than 30 ms. For example, when the detection time t p of the peak resistance R peak is 30 ms or less, the dwell time may be in the range of 1 ms to 10 ms, and in the case of 30 ms or more, it may be in the range of 10 ms to 20 ms. This means that the recovery current value can be set to be smaller than the reference current when the detection time t p of the peak dynamic resistance (R peak ) is equal to or shorter than the predetermined time, and the amount of heat that can be generated in this case is compensated for It is necessary to shorten the downtime (i.e., the time during which the cooling takes place). On the other hand, when the detection time (t p ) of the peak dynamic resistance (R peak ) is longer than a predetermined time, the problem caused by the relatively initial input heat amount is reduced, and thus the dwell time can be relatively increased.

After the lapse of the resting time (t r , t off ), the welding material 10 is gradually applied with the current decreasing (S16). That is, a current is applied to the welding material 10 based on the elapsed time of the resting time (t r , t off ), and the current can be gradually reduced while being applied. By controlling the current, the supply of unnecessary heat can be cut off, and the damage of the welding material 10 due to the unnecessary heat can be reduced. Here, the application end point of the current may be the time point at which the predetermined total welding time has elapsed since the current is applied to the welding material 10. The initial current value i dn1 and the latter current value i dn2 may be the maximum current value and the minimum current value in the corresponding step S16 in the step S16 of applying the current while decreasing the current.

The peak copper resistance (R peak) detecting, as shown in Figure 6 (S14; FIG. 1) is a step of measuring n times a period of a resistor t 1 of a concrete example, the weld material 10 ( And a step S22 of detecting the maximum resistance among the measurement resistances of the weld material 10 as a peak dynamic resistance R peak . In this case, the measurement period of the peak dynamic resistance R peak is t 1 ㅧ n. For example, it is possible to detect the peak dynamic resistance (R peak ) by applying a current to the welding material 10 a predetermined number of times at intervals of 10 ms. At this time, the peak dynamic resistance (R peak ) can be the maximum resistance having the largest value when the current is applied to the weld material 10 a predetermined number of times. Also, the measurement period of the peak dynamic resistance (R peak ) can be expressed, for example, as 10 ms 3, or 30 ms.

The peak copper resistance (R peak) detecting, as shown in FIG 7 (S14; shown in Fig. 1) As another example, the weld material 10 to the current t 1 period n times applied to the peak copper in When the resistance (R peak ) is measured, the peak dynamic resistance (R peak ) can be measured by repeating the measurement period one more time based on the detection of the peak dynamic resistance (R peak ). For example, the peak dynamic resistance (R peak) detecting a detection step (S31), the peak dynamic resistance (R peak) in the n x-th of the n times, measuring n times a period of a resistor t 1 of the weld material 10 to when the cycle of a resistance weld t 1 based on (S32), n-th x may include the step (S33) for repeatedly measuring n times. Here, the step S33 of repeatedly measuring the resistance of the welding material is performed such that when a new peak dynamic resistance is detected by the power supply control unit 30 in the repeated measurement process, the resistance is updated to the peak dynamic resistance R peak , It may be repeatedly performed a predetermined number of times, for example, one time, and as another example, it may be repeatedly performed until a new peak dynamic resistance is not detected in the repeated measurement process.

The control method of the spot welder according to the embodiments of the present invention can be written in a computer program. The code and code segments that make up this computer program can be easily inferred by a computer programmer in the field. Also, the computer program may be stored in a computer-readable recording medium, read and executed by a computer, and implemented or implemented in a control method of the spot welder.

FIG. 8 is a graph showing current, voltage and dynamic resistance waveforms according to an example of a method of controlling a spot welder according to the present invention. When the control variables are as shown in Table 1 below, And the change in dynamic resistance.

division Condition At least the same resistance (Rmin) detects a time interval (t 2) 5ms Peak dynamic resistance (Rpeak) detection time interval (t 1 ) 10ms Constant current holding value 80% of the reference current The initial current time (t in ) 20ms The maximum current value (t upmax ) of the current increasing step (S13) 120% of the reference current The rising current time t up of the current increasing step S13, 30ms The dwell time (t off ) of the current off step (S15) 5ms The initial current value (i dm1 ) of the current reduction step (S16) 80% of set current The latter current value (i dm2 ) of the current reduction step (S16) 60% of set current

Table 2 shows the tensile test results of the welded material welded by the control method of the spot welder according to the embodiment of the present invention. The welding was performed by using the hot-dip galvanized steel sheet SGAFC1180Y (thickness 1.2 mm) and SGACEN (thickness 1.1 mm) And the tensile strength (unit: kN) at the welded portion. The total welding time was 200ms, 250ms, and 300ms, and the reference current varied from 7kA to 12kA for each welding time. In all the conditions tested, the fracture of the weld zone showed a button fracture indicating good weld characteristics.

Welding time
(ms) 7kA 8kA 9kA 10kA 11kA 12kA 300 4.2 4.6 4.8 6.0 6.3 5.9 250 3.1 4.1 4.5 5.9 6.0 5.7 200 3.1 3.9 4.0 5.5 5.8 6.0

Table 3 shows the results of the continuous ROT test under the conditions of a reference current of 11 kA and a welding time of 250 ms using SGAFC1180Y (thickness 1.2 mm) and SGACEN (thickness 1.1 mm). According to the present invention, it is understood that the present invention does not cause warpage to 500 RBs, all of the button ruptures occur, and the decrease in tensile strength does not occur much.

The tensile strength
(kN) 6.2 6.1 6.2 5.8 5.8 5.8 5.9 5.7 6.0 5.9 Other score 50 100 150 200 250 300 350 400 450 500 Nugget size (mm) 5.5 5.6 5.3 5.6 5.3 5.4 5.7 5.2 5.5 5.4 Fracture type Button break

Table 4 shows the result of the tensile test by the method of controlling the spot welder according to the embodiment of the present invention. As a result of spot welding using SGAFC1180Y (thickness 1.2 mm) and SGAFC590DP (thickness 0.9 mm) Tensile strength (unit: kN). The total welding time was 200ms, 250ms, and 300ms, and the reference current was changed from 6kA to 10kA for each welding time. The failure of the weld zone in all the tested conditions indicated the button failure.

Welding time
(ms) 6kA 7kA 8kA 9kA 10kA 300 5.3 7.1 8.8 9.1 9.1 250 4.8 7.5 8.2 8.6 9.3 200 4.6 7.0 8.0 8.4 8.6

Table 5 shows the results of the continuous ROT test under conditions of a reference current of 8 kA and a welding time of 250 ms using SGAFC1180Y (thickness 1.2 mm) and SGAFC590DP (thickness 0.9 mm). According to the present invention, it can be seen that the present invention does not cause warping to 1000 RBs, all of the button ruptures occur, and the tensile strength deterioration does not appear much.

The tensile strength
(kN) 8.1 8.0 8.0 8.3 8.3 8.4 8.1 8.3 8.2 8.1 7.9 Other score One 50 100 150 200 250 300 350 400 450 500 Nugget size (mm) 4.3 4.3 4.3 4.4 4.4 4.5 4.4 4.5 4.5 4.4 4.4 Fracture type Button break The tensile strength
(kN) 8.1 7.9 8.1 8.0 7.8 7.7 7.9 7.9 7.8 7.8 - Other score 550 600 650 700 750 800 850 900 950 1,000 - Nugget size (mm) 4.3 4.2 4.1 4.3 4.2 4.1 4.2 4.2 4.2 4.3 - Fracture type Button break

Table 6 shows the result of the tensile test by the method of controlling the spot welder according to the embodiment of the present invention. As a result of spot welding using SGAFC1180Y (thickness 1.2 mm) and SGAFC590 (thickness 0.9 mm) Tensile strength (unit: kN). The total welding time was 200ms, 250ms and 300ms, and the reference current was changed from 6kA to 10kA by welding time. In all the conditions tested, the fracture of the weld zone showed button fracture.

Welding time
(ms) 6kA 7kA 8kA 9kA 10kA 300 6.6 7.7 9.3 9.8 9.0 250 4.9 7.4 9.1 9.5 8.8 200 4.6 7.0 9.0 9.1 9.2

Table 7 and Table 8 show the result of tensile test by the method of controlling the spot welder according to the embodiment of the present invention. As a result, the welded part was spot welded using SPRC440 (thickness: 1.0 mm) It is investigated.

Table 7 shows the cases where the peak detection time (R peak ) is less than 30ms, and the recovery current recovered at the end of the rest period was 80% of the reference current. Also, during the rest period, the current value applied to the welding material was 0% of the reference current (that is, the current was off), 30%, 50%, and 70%. The reference current was 9 kA. When the current was off, the dwell time was 5 ms, and in the remaining cases, the dwell time was 15 ms.

Table 8 shows that the peak detection time (R peak ) exceeded 30ms and that the recovery current was 100% of the reference current, as compared with Table 7.

FIG. 9 shows the result of observing the fracture surface of the welded portion according to the above conditions.

As shown in Table 7, Table 8 and FIG. 9, button breakage was observed at the welds under all conditions, and it was found that the characteristics of the welded portions were very good according to the embodiment of the present invention.

Recovery current 80% of the reference current Downtime
(Current holding time) 5ms 15ms Holding current
(% Relative to the reference current) 0% 30% 50% 70% Fracture type Button break

Recovery current 100% of the reference current Downtime
(Current holding time) 5ms 15ms Holding current
(% Relative to the reference current) 0% 30% 50% 70% Fracture type Button break

While the present invention has been described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: welding material 20: electrode
30: power supply control unit 40:

Claims (13)

A current applying step of applying a current to the welding material while gradually increasing the current through at least one electrode;
Detecting a peak copper resistance (R peak ) of the weld material while applying the current gradually increasing;
A current sustaining step of applying the current while continuously increasing the peak dynamic resistance Rpeak;
Reducing the current applied to the weld material for a predetermined period of time after the current sustain step;
Applying gradually decreasing current to the weld after the recovering step;
Wherein the method comprises the steps of: The method according to claim 1,
Further comprising the step of applying a current of a magnitude set to the welding material constantly for a predetermined period of time prior to the step of gradually increasing and applying the current. The method according to claim 1,
Wherein the step of reducing and recovering the current applied to the weld material for a predetermined period of time comprises turning off the current applied to the weld material during the set time. The method according to claim 1,
Wherein the step of reducing and recovering the current applied to the welding material for a predetermined time period comprises the step of controlling the welding current to be applied to the welding material at a point of time when the recovery is completed at a time corresponding to 100% . The method according to claim 1,
Wherein the step of reducing and recovering the current applied to the welding material for a predetermined period of time has a value smaller than a predetermined reference current when the recovery is completed. The method according to claim 1,
Wherein the time from when the electric current is applied to start the welding to when the peak dynamic resistance (R peak ) appears is 30ms or less. The method according to claim 1,
Wherein the time from when the electric current is applied to start the welding to when the peak dynamic resistance (R peak ) appears exceeds 30 ms. The method according to claim 1,
The set time,
1 ms to 10 ms when the detection time of the peak dynamic resistance (R peak ) is 30 m or less,
And when the detection time of the peak dynamic resistance (R peak ) is more than 30ms, it is 10ms to 20ms. The method according to claim 1,
The step of detecting the peak dynamic resistance (R peak )
Measuring the resistance of the weld material n times at intervals of t 1 ; And
Detecting a maximum resistance among the measurement resistances of the weld material as the peak copper resistance (R peak );
Wherein the method comprises the steps of: The method according to claim 1,
The step of detecting the peak dynamic resistance (R peak )
Measuring the resistance of the weld material n times at intervals of t 1 ; And
When detecting the peak copper resistance (R peak) in a n x n-th of the time, comprising: a resistance measuring the weld material repeat n times the period t 1 on the basis of the n-th x;
Wherein the method comprises the steps of: The method according to claim 1,
The step of repeatedly measuring the resistance of the weld material comprises:
And when a new peak dynamic resistance is detected, updating it to the peak dynamic resistance (R peak ), and repeating it a predetermined number of times. The method according to claim 1,
The step of detecting the peak dynamic resistance (R peak )
Wherein the measurement resistance of the weld material is performed within a maximum allowable resistance or within a maximum allowable current applied to the weld material. A recording medium on which a program for performing the control method of the spot welder according to any one of claims 1 to 12 is stored.
KR1020150099954A 2015-07-14 2015-07-14 Control method of spot welder and recording medium for storing program thereof KR101739941B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1020150099954A KR101739941B1 (en) 2015-07-14 2015-07-14 Control method of spot welder and recording medium for storing program thereof
PCT/KR2016/007551 WO2017010787A1 (en) 2015-07-14 2016-07-12 Spot welder control method and recording medium in which program thereof is recorded

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020150099954A KR101739941B1 (en) 2015-07-14 2015-07-14 Control method of spot welder and recording medium for storing program thereof

Publications (2)

Publication Number Publication Date
KR20170008592A KR20170008592A (en) 2017-01-24
KR101739941B1 true KR101739941B1 (en) 2017-05-26

Family

ID=57757113

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020150099954A KR101739941B1 (en) 2015-07-14 2015-07-14 Control method of spot welder and recording medium for storing program thereof

Country Status (2)

Country Link
KR (1) KR101739941B1 (en)
WO (1) WO2017010787A1 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015049998A1 (en) * 2013-10-04 2015-04-09 Ｊｆｅスチール株式会社 Resistance spot welding method

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20010038882A (en) * 1999-10-28 2001-05-15 이준웅 Apparatus for compensating rewelding state of resistance spot welder
JP2004090037A (en) * 2002-08-30 2004-03-25 Murata Mfg Co Ltd Resistance welding method, electronic parts, irreversible circuit element and communication device
KR100653257B1 (en) * 2005-09-29 2006-12-05 정연강 Controller of welding machine for ultra-precision
JP5388822B2 (en) 2009-03-13 2014-01-15 Ｊｆｅケミカル株式会社 Method for producing lithium iron phosphate
US8455929B2 (en) 2010-06-30 2013-06-04 Taiwan Semiconductor Manufacturing Company, Ltd. Formation of III-V based devices on semiconductor substrates
KR101219473B1 (en) * 2010-09-28 2013-01-11 이희준 Smart welding control divice and control method

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015049998A1 (en) * 2013-10-04 2015-04-09 Ｊｆｅスチール株式会社 Resistance spot welding method

Also Published As

Publication number Publication date
KR20170008592A (en) 2017-01-24
WO2017010787A1 (en) 2017-01-19

Similar Documents

Publication Publication Date Title
EP3053693B1 (en) Resistance spot welding method
KR101906084B1 (en) Resistance spot welding method
KR101974298B1 (en) Resistance spot welding method
KR101953054B1 (en) Resistance spot welding method and method for manufacturing resistance spot welded joint
KR101880380B1 (en) Resistance spot welding device and resistance spot welding method
JP6471841B1 (en) Resistance spot welding method and manufacturing method of welded member
JP6590121B1 (en) Resistance spot welding method and manufacturing method of welded member
US20070029288A1 (en) Method and apparatus for resistance spot welding
KR101739941B1 (en) Control method of spot welder and recording medium for storing program thereof
KR101771147B1 (en) Welding power control method, apparatus and computer-readable medium recording the method
JP3970469B2 (en) Temper bead method
KR101739947B1 (en) Spot welding control method
JP6904479B2 (en) Resistance spot welding method and welding member manufacturing method
CN112262012B (en) Resistance spot welding method and method for manufacturing welded member
KR101552241B1 (en) Control method of intelligent spot welder and recording medium for storing program thereof
KR101886330B1 (en) Control method of spot welder and recording medium for storing program thereof
JP5988015B1 (en) Resistance spot welding method
KR102617967B1 (en) Resistance spot welding method and weld member production method
JP2019034341A (en) Resistance spot welding method and manufacturing method for welding member
KR101987967B1 (en) Arc welding control method
JP4296648B2 (en) Electrode displacement control method and apparatus for resistance welding
CN112368101B (en) Resistance spot welding method and method for manufacturing welded member
JP2022105379A (en) Manufacturing method for resistance spot weld joint and resistance spot welding device
JP2023046247A (en) Welding quality evaluation device, welding quality evaluation program, and welding quality evaluation method
JP2009028787A (en) Method and apparatus for control of resistance brazing

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant