JPH0985443A - Arc welding equipment and welding condition setting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically set welding conditions peculiar to a product desired by the manufacture or those securing a superior welding quality, without intervening a welding program prepared by a robot maker. SOLUTION: A welding controller 4 which automatically sets the welding conditions of an electric current and voltage to be outputted from a welding power source 3 to issue an output command to the source 3 is provided. The controller 4 receives from a robot controller 5 only a signal 5a for calling conditions for reading the set welding conditions synchronously with the teaching data transmitted to a robot 2 by the robot controller 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a consumable electrode type arc welding apparatus using a shield gas and a welding condition setting method.

[0002]

2. Description of the Related Art As shown in FIG. 15, a basic system of a conventional automatic arc welding apparatus sends a welding condition command and a drive signal based on teaching data to a combination of a welding power source 101 and a robot 102, A central processing type welding robot controller 103 for controlling the cooperative welding work of the welding power source 101 and the robot 102 is provided.

Here, the welding conditions refer to current, voltage, and welding speed, which are determined in advance for each joint by experiments and experience, and the welding robot controller 103 is operated by the operator.
It is input as a current command parameter and a voltage command parameter in which the characteristics of the welding power source 101 are corrected. The welding robot controller 103 includes a condition file 10 including a memory area 103e in which teaching data is stored and a memory area 103d in which welding conditions specified for each joint are stored.
3a, a control unit 103c that converts teaching data into the drive signals for the axes of the robot 102, and a D / A converter 103b that converts the command parameters from the file 103a into analog signals, and start welding. The welding conditions are read in synchronization with the teaching data read by the. That is, the welding robot controller 1
03 is a memory area 103 storing welding conditions for each joint
The welding program of d and the robot program of the memory area 103e in which the teaching data is stored are controlled to be read in synchronization.

[0004]

By the way, in a controller of a recent welding robot, welding conditions are automatically set or welding conditions are automatically managed in accordance with a disturbance during welding under a situation such as lack of experienced workers. They tend to incorporate welding programs. A robot manufacturer usually designs such a welding program to be incorporated in a robot program for reading teaching data.

However, an actual product maker may want to modify a welding program created by a robot maker or add a special function relating to welding to perform product-specific welding. In such a case, it is necessary to obtain the details of the welding program created by the robot maker, but in general, the manufacturer program should not be published, and the product manufacturer should modify the robot manufacturer's welding program or add new functions. Is not easy.

Incorporating the welding program in the welding robot controller means that the welding program and the robot program are communicatively linked, and the welding program is compatible only with a specific welding power source and robot combination. If the welding power source changes, the welding program of the welding robot controller will have to be modified.

Therefore, the present invention can freely cope with the change of the robot and the welding power source by controlling only the welding process by the program unique to the product manufacturer without depending on the welding program conventionally created by the robot manufacturer. At the same time, the arc welding equipment and its welding conditions can be set automatically by simply inputting the basic specifications instructed in the design drawing and welding conditions peculiar to the product considered by the product manufacturer and welding conditions ensuring good welding quality. To provide a setting method.

[0008]

SUMMARY OF THE INVENTION The gist of the invention of claim 1 which has solved the above-mentioned problems is (a) a robot which holds a welding torch to which a wire is fed and which steers the welding torch according to teaching data. b) Welding power source that outputs current and voltage to the welding torch; (c) Welding conditions consisting of command parameters of current and voltage output from the welding power source and welding speed are stored in a condition file for each joint of the product. And (d) in transmitting the teaching data and the signal indicating the welding speed to the robot, the timing at which each command parameter is output from the welding controller to the welding power source is the timing at which the teaching data is transmitted. Robot controller that commands the condition call timing to the above welding controller in synchronization with The controller that controls the arc welding is composed of a welding controller that controls the welding process related to the welding torch and a robot controller that controls the movement of the robot. A program for setting and managing welding conditions can be accumulated to perform unique welding without relying on robot manufacturers.

The gist of the invention of claim 2 which solves the above problem is applied to both the case where the welding controller and the robot controller are separated and the case where they are not separated. The number of layers, the welding current and the welding voltage are set for each joint based on the basic specifications described above, and the command parameters of the current and the voltage output from the welding power source and the welding speed are set.

Here, the basic specifications are joint shape, posture,
Welding method (pulse transfer, spray transfer type and short-circuit transfer type in the case of MAG welding), leg length, distance between chip base materials, and plate thickness or welding speed or welding cross-section other than fillet welding, if necessary. A welding condition setting method according to claim 3 which is dependent on claim 2 is a method of setting the number of layers based on basic specifications, wherein (a) a welding cross-sectional area is calculated from an input designated leg length, and (b) From the welding cross-sectional area and the given welding posture, the shape of the molten weld metal is judged to be good or bad, and it is decided whether it is a single layer or a multi-layered layer. (B) When changing to the multi-layered layer, the leg length is set accordingly. Then, the teaching point is instructed to be changed, and (d) when it is judged that the leg length of the multi-layer pile is not in the shape, the instruction of the leg length over is performed.
The method for determining the quality of the deposited metal is described in the examples.

A welding condition setting method according to claim 4 which is dependent on claim 2 is a method of calculating a welding current and a welding speed when the welding speed is not input as a basic specification, and comprises (a) a wire feeding speed and The condition of welding current and welding speed provisionally determined from the leg length is added to each relational expression of welding current and wire feeding speed and welding speed, and (b) the wire feeding speed by the provisionally determined welding current and welding speed is The step of setting the welding current and the welding speed when both the above relational expressions are satisfied to the set welding current and the set welding speed.

A welding condition setting method according to claim 5 which depends on claim 2 is a method of setting a current command parameter based on a basic specification, wherein (a) the current command parameter is a function of a leg length and a welding speed. It is expressed by a geometrically determined polynomial, and (b) is used to calculate the current command parameter. Claim 6 dependent on Claim 2
The welding condition setting method in 1) is a method of setting the welding voltage based on the basic specifications, and the welding voltage is calculated by a polynomial including not only the function of the welding current but also the function of the distance between the tip base materials.

A welding condition setting method according to claim 7 which depends on claim 2 is a method for setting a welding voltage in the case of pulse welding, wherein (a) the polynomial is calculated from a boundary current according to a distance between chip base materials. It is divided into two calculation formulas, a high current side and a low current side. (B) When the set welding current is larger than the boundary current, the set welding voltage is calculated from the calculation formula on the high current side,
(C) When the welding current is smaller than the boundary current, there is a step of calculating the set welding voltage from the calculation formula on the low current side.

A welding condition setting method according to claim 8 which depends on claim 2 is a method for setting a welding voltage in the case of mag welding, wherein (a) the above polynomial expression is an arithmetic expression for performing spray transfer welding. There is a step of dividing into arithmetic expressions for performing the short-circuit transfer type welding, and (b) selecting each of the above arithmetic expressions according to the input basic specifications. A welding condition setting method according to claim 9 which depends on claim 2 calculates a penetration depth from (a) a set welding voltage, a set welding current and a set welding speed,
(B) Current command parameter and voltage command parameter from the set welding voltage and the set welding current to the welding power source when the penetration depth is between the upper limit penetration depth and the lower limit penetration depth according to the plate thickness (C) If the penetration depth is out of the range of the upper limit penetration depth and the lower limit penetration depth and the welding speed is not entered as the basic specification, the set welding current is corrected to And (d) when the welding speed is input as the basic specification, the welding speed is corrected and the welding current is recalculated accordingly.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an arc welding apparatus and a welding condition setting method therefor according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the equipment for realizing the arc welding apparatus and the welding condition setting method of the present invention includes a welding torch (hereinafter,
A torch) 1 for holding a multi-joint robot 2, a welding power source 3 for supplying power to the tip 16 of the torch based on the welding power output of the output terminals 3a, 3b, a current I and a voltage V of the welding power output. each command parameter command to the welding power source 3 to be output from the welding power source 3 P _I, P
A welding controller 4 for automatically setting _V and sending out respective command signals i, v, a robot controller 5 for controlling the articulated robot 2 based on teaching data TD including a command signal for welding speed, and a drum 6. It is composed of a wire feeder 8 for feeding the filled wire 7 as a consumable electrode to the torch 1 and a jig 9 on which a welded article is placed. It is assumed that the articulated robot 2 is provided with a waveform operation circuit for converting the teaching data TD into a drive signal format for operating the actual robot shaft portion based on the welding speed.

The wire feeding device 8 assembled to the articulated robot 2 includes a bending straightener 11 and an encoder 1.
2. A pair of feeding rollers 13a, 13 holding the wire 7 therebetween.
b, a rotary actuator 14 that drives the rollers 13a and 13b, and a torch cable 1a that guides the wire 7 to the torch 1, and the wire 7 is projected from the tip 16 in the nozzle portion 15 of the torch 1.
Then, the rotary actuator 14 is controlled by the drive signal of the feed speed proportional to the magnitude (average value) of the welding current i from the welding controller 4 to feed out the wire 7, and the detected wire feed at that time is fed. The feed rate MR _a is sent from the encoder 12 to the welding controller 4.

The welding controller 4 automatically sets the welding conditions (current, voltage and speed) and automatically corrects the welding conditions with respect to disturbance, and its hardware is conceptually shown in FIG. As described above, the joint shape, posture, welding method (pulse transfer, spray transfer type and short-circuit transfer type in the case of mag welding), leg length L, tip base metal distance EXT (distance between tip 16 and base metal), and plate thickness t Or, if necessary, basic specifications such as welding speed or welding cross-sectional area other than fillet welding are input to the specification input means 41 and the specification input means 41, for example, for each N joints in one product. In the initial condition setting means 42, the initial condition setting means 42 for determining the welding conditions based on the basic specifications described above, the arithmetic expression memory 43 in which each arithmetic expression used in the calculation of the initial condition setting means 42 is stored, and the initial condition setting means 42. A condition file 45 for storing the set welding condition I, modified current command parameters corresponding to the disturbance of the initial current command parameter P _I and the initial voltage command parameter P _V of the welding condition set in the initial condition setting means 42 It is mainly composed of P _I ′ and a condition automatic management correction means 44 for setting the corrected voltage command parameter P _V ′.

The corrected current command parameter P _I ′ and the corrected voltage command parameter P _V ′ in digital signal form are D
The / A converter converts the analog current command signal i and the voltage command signal v into the welding power source 3, and commands the current and voltage to be derived from the output terminals 3a and 3b. In addition, the welding controller 4 includes
Detection welding current I _a of the current and voltage outputs from the welding power source 3 (when pulse welding is the average current of the pulse current) and the detection welding voltage V _a is adapted to be sampled.

Here, the initial current command parameter P _I
And the relationship between the modified current command parameter P _I ′ and the welding current I and the relationship between the initial voltage command parameter P _V and the modified voltage command parameter P _V ′ and the welding voltage V are as follows:
The relationship is set by correcting the characteristics of. That is, the current command parameters P _I and P _I ′ and the voltage command parameters P _V and P _V ′ are set so that the welding current and the welding voltage calculated in the welding controller 4 are output even if the welding power source changes. It is corrected every time.

On the other hand, the robot controller 5 is an electronic controller having a teaching data memory for each joint, and the robot controller 5 is used for actual welding.
Reads the data in each memory in order and reads the articulated robot 2
Each of the axes is driven and a condition calling signal 5a is sent to the welding controller 4 every time one memory is read out to access the condition file 45. As a result, the welding conditions (P _I , P _{I) for} each joint are synchronized with the teaching data TD.
_V , I, V and welding speed WS) are read.

The set of each arithmetic expression to be stored in the arithmetic expression memory 43 is obtained in advance by experiments. An arc ON / OFF signal, which means start and stop of main welding, is sent from the robot controller 5 to the welding controller 4. The arc welding apparatus of the present invention is configured as shown in FIG. 1, and the welding controller 4 receives a condition calling signal 5a from the robot controller 5 for a program relating to a welding process performed in cooperation with the teaching data of the robot controller 5. Only the initial condition setting means 4
2 and condition automatic management correction means 44.

Therefore, the welding controller 4 can set a program that is not linked to the robot program stored in the robot controller 5, and can perform welding unique to the product maker without relying on the robot maker. Further, by separating the welding controller 4 from the robot controller 5, the welding controller 4 does not participate in any control related to the motion of the robot, so that the welding conditions of the welding controller 4 are changed even if the type of the robot 2 changes. There is no need and it is a very versatile welding management system.

Next, how the welding controller 4 sets the arc welding conditions will be described with reference to the flowcharts of FIGS. 3 to 8 and the characteristic diagrams of FIGS. 9 to 14.
As shown in FIG. 3, the overall configuration includes a preparation process including step S ₁ [basic specification input] and step S ₂ [automatic setting of optimum welding conditions], and step S ₄ [main welding start], step S ₁₈ [Requirement automatic management] and welding end (step S ₁₄₎ and consists of a main welding process including a preparation process specification input means 41 and the initial condition setting means 42 performs processing, the welding conditions automatically managed correcting means 44 Is a process performed by. However, between the preparation process and the welding process, the welded joint and is determined whether the step S ₃ there is a gap (between the ski) is inserted into, if the gap is there a step S ₁₇ [gap Automatic management]. In addition,
The automatic management when there is this gap and the processing in the main welding are not directly related to the present invention, and therefore the description thereof is omitted.

In the welding condition setting method of the present invention, the above step S ₂ , that is, the leg length setting (determination of one layer or multiple layers, etc.) and subsequent welding speed are automatically set (when the welding speed is not input). When welding conditions are set) and when welding speed is manually set (welding conditions are set when welding speed is input), condition setting for pulse welding and spray transfer type welding in MAG welding are performed. It is characterized by setting conditions when performing welding and setting conditions when performing short-circuit transfer type welding in MAG welding.

Now, the basic specification input of the above step S ₁ is the processing at the beginning of FIG. 4, except for the joint shape, posture, welding speed WS, leg length L, tip base metal distance EXT, plate thickness t, and fillet. The welding cross-sectional area A ₁ , the boundary constant K ₈₆ of the penetration depth and the minimum penetration depth ensuring constant K ₈₇ are input. This input is performed by the operator's key operation. After setting the leg length and inputting the basic specifications, in step _S201 [joint shape = fillet], it is determined whether the joint shape is fillet welding or other welding (for example, butt welding). When the joint shape is fillet welding, step S ₂₀₄ [L ≦ 5] → step S ₂₀₅ [L =
L + K ₁₄₂ ] → S ₂₀₆ [Skin fillet cross-sectional area A = (1/2) L
² ] is performed to calculate the fillet cross-section area. In the calculation of the fillet cross-sectional area, first, if the specified leg length is 5 mm or less, the constant K
₁₄₂ (for example, 0.5 mm) is added to correct the leg length (S ₂₀₄ → S ₂₀₅ ). When the leg length is determined, the fillet cross-sectional area A is calculated in step _S206 .

Whether or not the next processing performed by the welding controller 4 can be carried out by one layer or two layers (here, two layers) without depending on the welding posture, does not cause a defective shape of the deposited metal at the current leg length. It is calculated and determined. That is, first, in step _S207 [posture = downward], it is determined whether the welding posture is downward or not downward (angle is present). If the joint posture is downward, step S ₂₀₈ [L ≦ K
₁₃₇ ] to execute the current leg length and a constant K ₁₃₇ (for example, 10 m
m]. As a result, in the case of L ≦ K ₁₃₇ , it is determined that welding is possible with the current leg length without causing further defective shapes, and the process proceeds to the next process (the leg length is finally set at this stage). > K ₁₃₇ , step S ₂₁₀ [L
≦ K ₁₃₈ ].

At step S ₂₁₀ , the current leg length and the constant K are set.
₁₃₈ (e.g., comparing the 15mm]. Constant K ₁₃₈ is a two-layer prime capable leg length value which does not cause shape defects in the case of orientation downward. Then, the defective shape if (current leg length L ≦ K ₁₃₈ If welding that does not occur is possible), step S
_{212 to} S ₂₁₅ [Teaching point change calculation command]
If L> K ₁₃₈ , it is determined that it is difficult to perform welding without causing a shape defect with the current leg length even with a two-layer heap, and step S is performed.
_{In 211} , the display of the leg length over is displayed.

The teaching point change calculation command is
Since it is assumed that the initial teaching points are even larger, the throat thickness r from the fillet cross-sectional area A calculated in step _S206 is calculated, and the teaching point is corrected by this value in order to keep the distance between the chip base materials constant. This is indicated to the operator by a display. If the joint posture is not downward in step _S207 , step _S216 [L≤K
₁₃₅ ], the current leg length L and a constant K ₁₃₅ (for example, 8 m
m]. The constant K ₁₃₅ is the maximum leg length value that allows further heightening without causing a shape defect in a case other than the downward posture. Welding if at step S _216, if the process proceeds to the next process, resulting in shape defects, step S ₂₁₇ [L ≦ K
Proceed to ₁₃₆ ]. The constant K ₁₃₆ (for example, 12 mm) is a leg length value that allows a two-layer pile without causing a defective shape when the posture is not downward. The constants K _{135 to} K ₁₃₈ are determined by experiments because the weight of the molten wire, the surface tension, etc. are involved due to the cross-sectional area of the fillet.

The leg length is corrected and the welding cross-section is calculated in steps S _{204 to} S ₂₀₆ , and the process of determining whether the layer is one-layer or multi-layer is used to secure an appropriate leg length for the joint shape and posture designated by the operator, and perform welding. Automatic setting with guaranteed strength is possible. By the way, when the joint shape is welding other than fillet welding, the process proceeds to step _S202 , and the welding cross-sectional area A is set to A ₁ at the time of inputting the basic specifications, and the subsequent step S203 _.
After setting the specified leg length to L = (2A ₁ ) ^1/2 , proceed to the welding speed manual setting algorithm. The welding speed manual setting algorithm is a process when the welding speed WS is specified by the basic specification input, but in the case other than fillet welding, the welding speed manual setting algorithm is automatically advanced. If you do not specify the welding speed in the basic specification input, in the subsequent step _S209 WS
It is judged to be automatic, and the welding speed is calculated in the subsequent processing.

Setting of Welding Current and Welding Speed As described above, the main welding controller 4 has a mode in which the welding speed is designated as a basic specification and a mode in which it is not designated. Which mode is determined in step _S209 (WS automatic). ing. Now, in the mode where the welding speed WS is not designated, the welding speed and the welding current are set by calculation. This calculation is performed by the wire feed speed MR, the welding current I (average current I _{aV in} the case of pulse welding) and the relational expression MR = f (I, EXT) of the distance between the tip base metal EXT and the wire feed speed M.
R = leg length L and welding speed WS relational expression MR = f (L, W
S) is used. However, for two relations, the unknown is M
There are three, R, WS and I, which cannot be solved.

Therefore, the following conditions are added to solve the problem. First, I _mAX (upper limit current) and WS _mAX (upper limit speed value) for each leg length are set as shown in FIGS. 9 and 10 based on experience so far. From this, I _mAX and WS _mAX can be expressed by the following equations.

[0032]

[ _Equation 1] I _mAX = K ₁₉ · L + K ₂₀ (when L ≦ 7)

[0033]

[ _Equation 2] I _mAX = K ₂₁ · L + K ₂₂ (when L> 7)

[0034]

[ _Formula 3] WS _mAX = -K ₁₀₂ · L + K ₁₀₃ (when L ≦ 5)

[0035]

[ _Expression 4] WS _mAX = -K ₂₃ · L + K ₂₄ (5 <L <10
In the case of), next, I _mAX determined from Formula 1 or 2 is substituted into MR = f (I, EXT), and the obtained MR is expressed by the relational expression MR = f (L, W
The welding speed WS can be calculated by substituting for S).
Then, the welding speed WS is further compared with WS _mAX obtained by the mathematical formula 3 or 4, and if WS is WS _mAX or less, WS and I _mAX at that time are the welding speed and welding current obtained.
_{Further, in} the case of WS> WS _mAX, the welding current is reduced until WS ≦ WS _mAX , the calculation is repeated, and the welding speed and the welding current when the same condition is satisfied are solutions to be obtained.

The above-mentioned calculation of the welding speed and the welding current is performed in step S ₂₁₉ [L ≦ 7] after determining WS automatic in FIG.
→ Step S ₂₂₀ and Step S ₂₁₉ → The upper limit current value is obtained in Step S ₂₂₁ and, after the judgment process of pulse welding or mag welding (Step S ₂₃₀ ), in the case of pulse welding, Step S ₂₃₁ [MR = f (I, EXT)] → step S
₂₃₂ [Calculation of welding speed WS] → step S ₂₃₃ [L ≦
5] → step S ₂₃₅ and step S ₂₃₃ → step S
_In the case of MAG welding at ₂₃₄ , step S ₂₅₁ [M in FIG.
R = f (I, EXT)] → step S ₂₅₂ [Welding speed W
Calculation of S] → Step S ₂₅₃ [L ≦ 5] → Step S
₂₅₄ and step S ₂₅₃ → step S ₂₅₅ , the upper limit speed value is calculated. Then, the obtained welding speed is WS> WS _mAX
In the case of pulse welding, whether or not it is determined in step _S236 .
For MAG welding is judged in step S _256, WS> WS
_If it is judged as _mAX , in the case of pulse welding, step S
₂₃₇ [I = I-1] the welding current is reduced unit weight in the case of MAG welding, by performing the same current reduction process in step S ₂₅₇ [I = I-1], until the WS is less WS _MAX The welding current is reduced stepwise and the calculation of the welding speed is repeated. Thus, the welding current and the welding speed can be calculated even when the welding speed is not input.

Setting of Welding Voltage Welding voltage V differs between pulse welding and mag welding. In the case of pulse welding, in order to take advantage of the characteristic that "the amount of spatter generated can be extremely reduced in principle",
As shown in the characteristic chart of No. 1, the short-circuit / non-short-circuit boundary at which both short-circuit type spatter that frequently occurs when the arc length is short and non-short-circuit type spatter that occurs when the arc length is long
It is optimal to find the balance of welding voltage with respect to welding current. This also leads to the limitation of the maximum arc length, which effectively acts to prevent undercut and improve the bead appearance.

Therefore, the number of short circuits is several times (for example, 1 time / s).
ec) When the voltage is feedback-controlled with respect to each current so as to be in the vicinity, and the relationship between the current and the voltage at the short-circuit / non-short-circuit boundary is obtained, the result is as shown in FIG. As shown in this characteristic diagram, it can be seen that the voltage at the short-circuit / non-short-circuit boundary increases as the welding current increases. This is because the voltage drop _VL of the wire protruding portion increases with the increase of the current, the potential gradient (voltage drop per arc length unit length) increases with the increase of the plasma air flow with the increase of the current, and the wire tip melts with the increase of the current. It is conceivable that the arc voltage V _A increases due to the sharpening and the increase in the arc length.

Further, in FIG. 12, the slope of the straight line is small on the low current side, and the slope is large on the high current side. It is considered that this is because the above effect becomes remarkable on the high current side. Further, FIG. 12 shows that the distance EXT between the chip base materials is 15, 20, 2
It is shown that the voltage at the short-circuited / non-short-circuited boundary increases for each current as it increases to 5 mm. It is considered that this is because the increase in the voltage drop V _L of the wire protruding portion due to the increase in EXT and the increase in the arc length due to the sharpening of the melting point at the wire tip due to the increase in resistance heating have an overlapping effect.

As described above, it was found that the welding voltage in the case of pulse welding exists at the boundary of short circuit / non-short circuit, which is represented by two functions of welding current and EXT as shown in FIG. Then, the data of FIG. 12 is subjected to a multiple regression analysis, and the welding voltage is represented by the function of the welding current and the EXT as follows.

[0041]

[Equation 5] High current side: V = K ₉ · I + K ₁₁ · EXT + K
_Ten

[0042]

[Equation 6] Low current side: V = K ₆ · I + K ₈ · EXT + K
₇ Here, the boundary current I _Cr between the high current side and the low current side is

[0043]

[Expression 7] I _Cr = K ₄ −K ₅ · EXT Therefore, if the welding voltage is calculated by using Equation 5 when the welding current I is larger than I _Cr and by using Equation 6 when the welding current I _Cr is smaller, it follows that the voltage at the short-circuit / non-short-circuit boundary that fluctuates depending on the welding current is followed. Therefore, a more optimal welding voltage can be obtained.

By the way, step S ₂₃₈ in Figure 5 calculates the demarcation current I _Cr than the distance between the input chip matrix, step S ₂₃₉ following the welding current I and the boundary current I
Comparing with _Cr . If the current is determined to be the high current side in step _S239 , the operation proceeds to step _S240 , in which the operation of equation 5 is performed. If the current is determined to be the low current side, the operation of equation 6 is performed in step S240.
Proceed to ₂₄₁ . The main welding controller 4 thus sets the welding voltage V.

When the welding voltage at the time of arc start is set slightly higher and lower than the short-circuit / non-short-circuit boundary, respectively, when welding is performed, as shown in FIG. 13 and FIG. Voltage is a little low (Fig. 1
In the case of 4), there are many short circuits at the start of welding, and the amount of spatter is considerably large. On the other hand, when the voltage at the start of the arc is set to be slightly higher (FIG. 13), the short circuit at the start of welding is hardly seen, and the start of welding without spatter generation is achieved. For the above reason, it is preferable that the set welding voltage at the start of welding is set to be slightly higher than the boundary between the short circuit and the non-short circuit.

On the other hand, the setting of the welding voltage in the case of the MAG welding starts with the judgment as to whether the spray transfer type welding or the short circuit transfer type welding is to be performed in step ₂₅₈ [Spray] of FIG. The operator sets which welding is to be performed for each joint when inputting the basic specifications. In the case of this mug welding,
As the calculation formula of the welding voltage, the one expressed by the polynomial of the welding current and the EXT is used. Step S ₂₅₉ [V = K ₇₇ · I + K ₇₈ · EXT +] when performing spray transfer welding
K ₇₉ ], and if short-circuit transfer type welding is to be performed, step S
Go to ₂₆₀ [V = _K74・ I + _K75・ EXT + _K76 ]. The difference between the respective arithmetic expressions is that the constants K ₇₉ and K ₇₆ of the coefficient term are mainly different, and K ₇₉ > K ₇₆ .

Welding current and welding current depending on penetration depth P
With the above correction, the calculation of the set welding current I, the set welding speed V, and the set welding voltage WS is completed for the time being. However, in the present invention, in the case of pulse welding and mag welding, the penetration depth is larger than the above I, V and WS. Is calculated (step S ₂₄₂ , step S
₂₆₁ ). Based on the result, it is continuously determined whether or not the setting is to be performed again. Step S ₂₄₅ [P <K ₈₆ · t] → step S ₂₄₆ [P ≧
K ₈₇ · t] (in the case of MAG welding, step S ₂₆₄ [P <K
₈₈ · t] → _S265 [P ≧ K ₈₉ · t]).
Here, K ₈₆ · t in step S ₂₄₅ is the upper limit penetration depth specified at the time of inputting the basic specifications according to the plate thickness t in the case of pulse welding, and K ₈₈ · t in step S ₂₆₄ is the value for mag welding. In this case, it is the upper limit penetration depth. Further, K ₈₇ · t in step S ₂₄₆ is the lower limit penetration depth in the case of pulse welding, and K ₈₉ · t in step S ₂₆₅ is the lower limit penetration depth in the case of mag welding. That is, the operation result if P is greater equal a lump limit penetration depth decreases unit quantity of current returns to step S ₂₃₇ (step S ₂₅₇ in MAG welding), re-calculates the welding speed, etc. In this reduced so current As in step S
Return to step ₂₃₁ (for mag welding, step _S251 ). Also,
If the calculation result P is smaller than the lower limit penetration depth, the current is increased by a unit amount in step S ₂₄₇ (step S _{266 in the} case of mag welding), and the increased current and welding speed etc. are recalculated in step S _231. Return to (step S ₂₅₁ ). When the calculation result P is between the upper limit penetration depth and the lower limit penetration depth, step S ₂₄₈ [P _V = K ₁₄ · V−
K ₁₅ ] (step S _{267 in} the case of mag welding), the voltage command parameter P _V is calculated, and the subsequent step S ₂₄₉ [P
_I = K ₁₂ × 10 ^-3 · L ² · WS-K ₁₃ ] (in the case of mag welding, step S ₂₆₈ [P _I = K ₈₀ × 10 ^-3 · L ² · WS-
K ₈₁ ]) calculates the current command parameter P _I.

Thus, the current I, voltage V, speed WS, current command parameter P _I , and voltage command parameter P _V are
Welding controller by setting process in step S ₂₅₀ 4
The command parameters P _I and P _V , which are stored in the condition file 45, are sent as command signals i and v to the welding power source 3 for each joint when the main welding is started. Here, an arithmetic expression for obtaining the current command parameter P _I (steps S ₂₄₉ , S
_The calculation formula used in ₂₆₈ ) may be calculated in the same form as the voltage command parameter P _V , but in the welding controller 4, the welding current I is not used and the leg length L and the welding speed WS are used.
Is determined by a function (P _I = a × 10 ⁻³ · L ² · WS-b) that can be derived from a purely geometrical method.
This is because if PI = f (I, EXT), there is an experimental error in obtaining this relationship, and this relational expression changes if the arc length at the time of the experiment is slightly different from that at the time of main welding. It is considered unsuitable to express the current command parameter P _I as a function of the welding current I and the distance between the tip base metals EXT. As described above, since the arithmetic expression for obtaining the current command parameter P _I in the main welding controller 4 is established only by the geometric condition, the strict wire feed amount for obtaining the target leg length L is secured. Become.

[0049] Setting of welding conditions when welding speed T is input
Fixed  The above welding conditions are set by the operator when entering the basic specifications.
Therefore, if the welding speed is not specified, set by calculation
It determines the welding speed. But the cycle tie
It is necessary to specify the welding speed from the relationship of
In this case, the main welding controller 4 is step S₂₀₉[WS own
7), the welding speed manual setting
Go to rhythm. This welding speed manual setting algorithm is
Set welding current I and set welding voltage based on input welding speed
The pressure V is calculated. The main welding controller 4 is
The leg length is calculated even when welding other than meat (step S₂₀₂, S
₂₀₃), Then proceed to the welding speed manual setting algorithm.
You.

Even with this welding speed manual setting algorithm,
The calculation formula for obtaining the current command parameter P _I is the same as when the welding speed is not input, and the leg length L and the input welding speed WS
Polynomial (P _I = a × 10
^-3 · L ² · WS-b) (step S ₂₇₁
(Pulse welding), step S ₂₉₁ (Mag welding)). Next, in the welding speed manual setting algorithm, the set welding current I is calculated from the current command parameter P _I (step S
₂₇₂ (pulse welding), step _S292 (mag welding)).
The arithmetic expression for calculating the set welding current I also uses a polynomial that is satisfied only by the geometric condition represented by the leg length L, the input welding speed WS, and the distance between the tip base metals EXT.

Step S for the subsequent pulse welding
₂₇₃[K₈₂≤I≤K₈₃] → Step S_{275 -}[I> K₈₃]
And step S for MAG welding₂₉₃[K₈₄≤I≤
K₈₅] → Step S₂₉₅[I> K₈₅] In the previous step
The welding current obtained in step 3
Correct the input welding speed WS according to whether it exceeds
In step S₂₇₆Or step S₂₇₇, Mug melt
In step S₂₉₆Or step S₂₉₇) Do
It is determined whether or not to proceed to the next process. And
When the input welding speed WS is corrected, the corrected welding speed
Again with welding current I and current command parameter P_ICalculate again
And repeat setting welding current setting. Where the constant K ₈₂Is
Current output range of welding power source 3 in pulse welding mode
Lower value of the constant K₈₃Is the same upper value, constant K₈₄Mug welding mode
The lower value of the current output range of the welding power source 3 during
Number K₈₅Is the same upper value.

Next, in the case of pulse welding, when the welding speed, the welding current, and the current command parameter are set, the step S ₂₇₈ [I ≧ I _Cr ] is performed as in the processing in which the welding speed is not input.
Then, it is determined whether to use the voltage calculation formula on the high current side (Formula 5) or the voltage calculation formula on the low current side (Formula 6). Set the welding voltage in each case. After the above welding voltage is set, step S ₂₈₁ [calculation of penetration depth P] is performed, and then step S ₂₈₂ [P <K ₈₆ · t] → step S ₂₈₄ [P ≧ K ₈₆ · t]. It is determined whether or not the calculated value P of the penetration depth is within the range of the upper limit penetration depth and the lower limit penetration depth. If the calculated value P is out of the same range, step _S283 [WS = WS-1] or step S283
₂₈₅ [WS = WS + 1] is used to correct the welding speed, and the corrected welding speed is used to return to the calculation of the welding current and the current command parameter. If the calculated value P is within the same range, step S
₂₈₆ [P _V = K ₁₄ · V-K ₁₅ ] set voltage command parameter P _V from welding voltage V (voltage obtained in step S ₂₈₀ )
Is calculated. After calculation of the voltage command parameter, welding conditions I, V, WS, P _I and P _V are stored in the condition file 45 in the weld controller 4 by setting process in step S _250. Then, with the start of the main welding, the command parameters P _I and P _{V for} each joint are changed to the command signals i and v.
Is sent to the welding power source 3.

Next, in the case of MAG welding, when the welding speed, the welding current and the current command parameter are set, the spray transfer type welding or short circuit transfer is performed in step ₂₉₄ [Spray], which is similar to the processing in which the welding speed is not input. determining whether to perform a type welding, if the specification input of spray transfer type welding step S using the same voltage calculation equation as step S ₂₅₉ in FIG. 6
_{In the} case of performing the short circuit transfer type welding by performing the calculation process of ₂₉₉ Fig. 6
Step S using the same voltage calculation formula as Step S _{260 of}
The calculation processing of ₂₉₈ is performed.

When the set welding voltage is determined by the above calculation processing, the step S is performed in the same manner as in the case of pulse welding.
The calculation of ₃₀₀ [calculation of penetration depth P] is performed, and the following step S ₃₀₁ [P <K ₈₈ · t] → step S ₃₀₃ [P ≧ K ₈₉
• When the calculated value P of the penetration depth is determined in [t] and the calculated value P is out of the same range, step S ₃₀₂ [WS
= WS-1] or step _S304 [WS = WS +]
1], the welding speed is corrected, the welding current and the current command parameter are calculated again at the corrected welding speed, and when the calculated value P is within the same range, step S ₃₀₅ [P _V = K ₉₇
V-K ₉₈ ], set the voltage command parameter P from the welding voltage V set.
Calculate _V And the determined welding conditions I, V, W
S, P _I and P _V are stored in the condition file 45 in the welding controller 4 by the setting process of step S ₂₅₀ .

Other Embodiments As another embodiment of the present invention, for example, when the welding speed and the welding speed are not input as the above-mentioned basic specifications, the setting method of the welding current and the welding speed is as follows. Is calculated, and the calculated upper limit speed value is MR = f
The wire feeding speed obtained by substituting (L, WS) for MR =
The calculated welding current is calculated by substituting it into f (I, EXT), and when the calculated welding current is less than or equal to the upper limit current value, the upper limit speed value is set as the set welding speed, and the calculated welding current is set as the set welding current. When the calculated welding current is larger than the upper limit current value, the upper limit speed value is decreased, the calculated welding current is recalculated based on the speed value after the decrease, and the calculated welding current is reduced to the upper limit current value or less. The calculation may be repeated to determine the set welding current and the set welding current.

Further, as a method for setting the welding current and welding speed when the above basic specifications are not entered, an arbitrary representative value is set from the upper and lower limits of the welding current and welding speed for each leg length, and the representative current value or representative speed value is set. Similarly, the wire feeding speed obtained in step S3 is calculated by the relational expression MR = f (I, EXT)
Alternatively, the welding speed and the welding current may be set by substituting = f (L, WS). In the embodiment, the reason why the upper limit current value and the upper limit speed value are used is that, for example, when it is calculated with the lower limit value, it is considered that the calculation speed requires time.

Next, the invention of the welding condition setting method for the arc welding apparatus may be applied to a control apparatus that stores both a welding program and a robot program. That is, the controller in this case is implemented as a welding robot controller that controls the welding torch and the robot (the robot controller and the welding controller that controls the welding process related to the welding torch are integrated).

Further, as described in the above embodiment, in the method of setting the welding current when the welding speed is input,
If the calculated welding current is out of the current output range of the welding power source, the welding speed is corrected according to whether it exceeds the upper value of the current output range, and the welding current is calculated again with the corrected welding speed. Then, the set welding current is reset.
According to this, even if the welding power source changes, it is possible to automatically set an appropriate welding current according to the welding power source.

[0059]

As described above, according to the invention of claim 1, the control device for controlling the arc welding is separated into the welding controller for controlling the welding process and the robot controller for controlling the motion of the robot, The welding controller can control the welding process simply by communicating the timing of the condition call from the robot controller. Therefore, the program that sets and manages the welding conditions is stored only in the welding controller without intervening in the program of the robot controller. It is possible to freely set the welding conditions unique to the product and the welding conditions ensuring quality without relying on the robot manufacturer's program that emphasizes the quality.

Further, according to the inventions of claims 2 to 10, since the welding conditions are automatically calculated based on the basic specifications input for each joint, even an inexperienced person can perform the basic operation specified in the design drawing. Appropriate welding conditions can be set simply by inputting specifications. In particular, in the aspect of claim 3, since it is automatically judged whether the layer is multi-layered or multi-layered, it is possible to prevent the weld metal from being defective in shape, and the operator can give a command for changing the teaching point or a command for leg length over in advance. Can be received (before welding).

According to the fourth aspect of the present invention, even if the welding speed is not input as the basic specification, the welding current and the welding speed can be calculated from the relational expression between the wire feeding speed and the welding current and the relational expression between the wire feeding speed and the welding speed. It can be calculated. According to the aspect of claim 5, the current command parameter and the set welding current are calculated by using a polynomial that can be derived from a purely geometrical method of only the leg length and the input welding speed. A strict wire feed is obtained to obtain the leg length.

According to the sixth aspect of the invention, the welding voltage is calculated by the polynomial of the welding current and the distance between the tip base materials, so that the optimum welding voltage can be set for any distance between the tip base materials. . According to the aspect of claim 7, when the welding voltage is calculated in the pulse welding, the boundary current is calculated according to the distance between the chip base materials in which the characteristic of the polynomial is changed, and the high current side and the low current of the boundary current are calculated. Since the above polynomials have different arithmetic expressions on the side, short circuit /
The voltage at the boundary of the V short circuit is followed, and a more optimal welding voltage can be set.

According to the eighth aspect of the present invention, when the welding voltage is calculated in the MAG welding, different calculation expressions are used for the above polynomial when the spray transfer type welding is performed and when the short circuit transfer type welding is performed. The welding voltage at the time of die welding and short-circuit transfer type welding can be appropriately set.
According to the aspect of claim 9, it is determined in advance whether the penetration depth is between the upper limit penetration depth and the lower limit penetration depth according to the plate thickness, and if the penetration depth is poor. It is possible to correct the welding condition once set in step 1 to secure an appropriate penetration depth.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the entire equipment embodying the present invention.

FIG. 2 is a conceptual diagram of FIG. 1 when a welding controller used in the present invention is represented by hardware.

FIG. 3 is a flowchart showing a program for the entire setting of welding conditions performed by the welding controller.

FIG. 4 is a flowchart mainly showing a leg length setting method according to the present invention.

FIG. 5 is a flowchart showing a welding condition setting method in pulse welding when a welding speed is not input.

FIG. 6 is a flowchart showing a welding condition setting method in MAG welding when a welding speed is not input.

FIG. 7 is a flowchart showing a welding condition setting method in pulse welding when a welding speed is input.

FIG. 8 is a flowchart showing a welding condition setting method in MAG welding when a welding speed is input.

FIG. 9 shows the characteristics of the upper limit current value for each leg length, where the vertical axis represents the current value and the horizontal axis represents the leg length.

FIG. 10 shows the characteristics of the upper limit speed value for each leg length, where the vertical axis represents the speed value and the horizontal axis represents the leg length.

FIG. 11 is a characteristic diagram showing the relationship between the amount of spatter generation and the number of short circuits in pulse welding, and the characteristics of the dotted line and the solid line were measured using different shield gases.

FIG. 12 is a characteristic diagram in which the relationship between the welding voltage and the welding current in pulse welding is obtained by experiments.

FIG. 13 is a measurement diagram in which a short circuit condition is recorded when the welding voltage at the time of arc start is set to be slightly higher than the short-circuit / non-short circuit boundary.

FIG. 14 is a measurement diagram in which a short circuit situation is recorded when the welding voltage at the time of arc start is set slightly lower than the boundary of short circuit / non-short circuit.

FIG. 15 is a block diagram showing an entire conventional arc welding apparatus.

[Explanation of symbols]

1 is a welding torch, 2 is a robot, 3 is a welding power source, 4 is a welding controller, EXT is a distance between chip base materials, I is a welding current, V is a welding voltage, MR is a wire feeding speed, WS is a welding speed, and i Is a current command signal, v is a voltage command signal,
In each figure, the same elements are given common reference numerals.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location B23K 9/127 509 8315-4E B23K 9/127 509D

Claims (9)

[Claims] 1. A robot that holds a welding torch to which a wire is fed and that operates the welding torch according to teaching data, a welding power source that outputs a current and a voltage to the welding torch, and a current that is output from the welding power source. Welding controller that stores welding conditions consisting of command parameters of voltage and voltage and welding speed in each condition for each joint of the product, and the above welding when sending the above-mentioned teaching data to the robot and the signal indicating the welding speed. An arc welding apparatus, comprising: a robot controller that commands a condition calling timing to the welding controller so that the timing of outputting each command parameter from the controller to the welding power source is synchronized with the timing of sending the teaching data. 2. A robot holding a welding torch, to which a wire is fed, sends teaching data and a signal indicating a welding speed to a robot, and commands each command parameter of current and voltage to a welding power source for feeding the welding torch. Therefore, it is a welding condition setting method for setting the welding conditions consisting of the command parameters and the welding speed for each joint of the product, and based on the basic specifications input for each joint, the number of layers for each joint,
A welding condition setting method for an arc welding apparatus, comprising setting a welding current and a welding voltage and setting respective command parameters of the current and voltage. 3. The method for setting the number of layers based on the basic specifications is to calculate a welding cross-sectional area from the input designated leg length,
From the welding cross-sectional area and the given welding posture, it is judged whether the shape of the molten weld metal is good or bad. If it is judged that the shape is good, a single layer is set according to the specified leg length. 3. The welding condition setting of the arc welding apparatus according to claim 2, wherein the leg length is set to instruct to change the teaching point, and when the leg length of the multi-layered pile is also judged to be a shape, the leg length over is instructed. Method. 4. When the welding speed is not input as the basic specifications, the method of setting the welding current and the welding speed based on the basic specifications is as follows: wire feeding speed and welding current, wire feeding speed and welding speed. The condition of welding current and welding speed provisionally determined from the leg length is added to the relational expression, and the welding current and welding when the wire feeding speed by the provisionally determined welding current and welding speed both satisfy the above relational expressions The welding condition setting method for an arc welding device according to claim 2, wherein the speed is set to a set welding current and a set welding speed. 5. The arc according to claim 2, wherein the method for setting the current command parameter based on the basic specifications is to calculate the current command parameter using a polynomial consisting of a function of leg length and welding speed. Welding condition setting method for welding equipment. 6. A method of setting a welding voltage based on the above basic specifications calculates a welding voltage with a polynomial consisting of a function of a welding current and a distance between tip base metals, and calculates a set welding voltage based on the polynomial. The welding condition setting method for an arc welding device according to claim 2, wherein: 7. In the case of pulse welding, the above polynomial is divided into two calculation formulas, a high current side and a low current side of the boundary current according to the distance between the tip base metals, and when the set welding current is larger than the boundary current. 7. The set welding voltage is calculated from the high current side arithmetic expression, and when the welding current is smaller than the boundary current, the set welding voltage is calculated from the low current side arithmetic expression. Welding condition setting method for arc welding equipment. 8. In the case of MAG welding, the above polynomial expression is divided into an arithmetic expression for spray transfer type welding and an arithmetic expression for short circuit transfer type welding, and each of the above arithmetic expressions is selected according to the input basic specifications. 7. The welding condition setting method for an arc welding device according to claim 6, wherein. 9. The penetration depth is calculated from the set welding voltage, the set welding current and the set welding speed, and the penetration depth is between the upper limit penetration depth and the lower limit penetration depth depending on the plate thickness. In the case of, the current command parameter and voltage command parameter to the welding power source are calculated from the set welding voltage and the set welding current, and the penetration depth is out of the range of the upper limit penetration depth and the lower limit penetration depth. In this case, when the welding speed is not input as the basic specification, the set welding current is corrected, and when the welding speed is input as the basic specification, the welding speed is corrected. Welding condition setting method for equipment.