JP3220894B2 - Arc welding apparatus and welding condition setting method - Google Patents

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 shielding gas and a method for setting welding conditions.

[0002]

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

Here, the welding conditions refer to current, voltage, and welding speed, which are determined in advance by experiments and experiences for each joint, and the welding robot controller 103 is operated by an operator.
The current command parameter and the voltage command parameter obtained by correcting the characteristics of the welding power source 101 are input. The welding robot controller 103 has a condition file 10 consisting of a memory area 103e storing teaching data and a memory area 103d storing welding conditions specified for each joint.
3a, a control unit 103c for converting the teaching data into the drive signals for each axis of the robot 102, and a D / A converter 103b for converting the command parameters from the file 103a into analog signals. The welding condition is read out in synchronization with the teaching data read out by the user. That is, the welding robot controller 1
03 is a memory area 103 storing welding conditions for each joint.
The control for synchronously reading out the welding program d and the robot program in the memory area 103e storing the teaching data is performed.

[0004]

By the way, a controller in a recent welding robot automatically sets welding conditions or manages welding conditions automatically according to a disturbance during welding under circumstances such as a shortage of experienced personnel. They tend to incorporate welding programs. The design for incorporating such a welding program into a robot program for reading teaching data is usually performed by a robot maker.

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

Incorporation of a welding program into a welding robot controller causes the welding program and the robot program to be communicatively linked, and is compatible only with a specific combination of a welding power source and a robot. If the welding power source changes, the welding robot controller's welding program must be modified.

Therefore, the present invention can freely respond to changes in the robot and the welding power source by controlling only the welding process with a program unique to the manufacturer, without depending on the welding program conventionally created by the robot manufacturer. At the same time, the welding conditions specific to the product considered by the product manufacturer and the welding conditions to ensure good welding quality are automatically calculated by simply inputting the basic specifications specified in the design drawings.
An object of the present invention is to provide an arc welding apparatus capable of setting appropriate welding conditions and a method for setting the welding conditions.

[0008]

Means for Solving the Problems The gist of the present invention, which has solved the above-mentioned problems, is that (a) a robot which holds a welding torch to which a wire is fed and steers the welding torch according to teaching data; b) a welding power source for outputting a current and a voltage to the welding torch ;
Joint shape, joint posture, welding method, leg length, distance between chip base materials
Input and calculate basic specifications including separation, thickness and welding speed.
And the current and voltage output from the welding power source by
Calculate welding conditions consisting of each command parameter and welding speed
Welding controller that outputs and stores it in the condition file
If, (d) the weld when sending a signal indicating the delivery and welding speed of the teaching data to the robot, the timing of outputting each command parameters to the welding power source from the welding controller synchronized with the transmission timing of the teaching data An arc welding apparatus is composed of a robot controller that instructs the above welding controller to call the condition call timing so that the robot and welding are performed.
Arc welding equipment that can freely respond to changes in power supply
That is. Therefore, the arc welding apparatus is separated into a robot controller for controlling the movement of the welding controller and the robot for controlling the welding process relates to the welding torch, to accumulate them program for setting a welding condition management only the welding controller robot We can perform original welding without relying on the manufacturer.

[0009] The gist of the invention according to claim 2 that solves the above-mentioned problem is that the basic specifications are input for each joint to be welded and input.
Number of welding layers , welding current and welding voltage based on the basic specifications
Is calculated and set and the current output from the welding power source.
Also calculates and sets each command parameter of voltage and welding speed.
To set welding conditions. This welding condition setting method is applied to both a system separated into a welding controller and a robot controller and a system not separated .

[0010] Here, the basic specifications are the joint shape, posture,
Welding method (spray transfer type and short-circuit transfer type in case of pulse and mag welding), leg length, distance between chip base materials, and sheet thickness or, if necessary, welding speed or welding cross-sectional area other than fillet welding. A welding condition setting method according to claim 3 which is dependent on claim 2 is a method for setting the number of layers based on basic specifications, wherein (a) a welding cross-sectional area is calculated from an inputted designated leg length, and (b) Judging the shape of the weld metal melted from the welding cross-sectional area and the given welding posture, it is determined whether the shape of the weld metal is good or not. (D) when it is determined that the leg length of the multi-layer building is not even the shape of the leg, the instruction is given to indicate that the leg length is exceeded.
The method of judging the shape of the deposited metal is described in Examples.

According to a second aspect of the present invention, there is provided a welding condition setting method for calculating a welding current and a welding speed when a welding speed is not input as a basic specification. The conditions of the welding current and the welding speed tentatively determined from the leg length are added to the respective relational expressions of the welding current and the wire feeding speed and the welding speed, and (b) the wire feeding speed based on the temporarily determined welding current and welding speed is calculated. A step of setting the welding current and the welding speed when both of the above relational expressions are satisfied as a set welding current and a set welding speed.

According to a second aspect of the present invention, there is provided a welding condition setting method for setting a current command parameter based on basic specifications, wherein (a) the current command parameter is a function of a leg length and a welding speed. It is represented by a geometrically determined polynomial, and (b) comprises the step of calculating the current command parameter using this. Claim 6 dependent on claim 2
Is a method of setting the welding voltage based on the basic specifications, and calculates the welding voltage by a polynomial including not only the function of the welding current but also the function of the distance between the chip base materials.

A welding condition setting method according to claim 7 which is dependent on claim 2 is a method for setting a welding voltage in the case of pulse welding, in which (a) the polynomial is calculated from a boundary current corresponding to a distance between chip base materials. (B) When the set welding current is larger than the boundary current, the set welding voltage is calculated from the high current side calculation formula,
(C) when the welding current is smaller than the boundary current, a step of calculating a set welding voltage from the low-current-side arithmetic expression.

According to a second aspect of the present invention, there is provided a welding condition setting method in which a welding voltage is set in a case of mag welding. (B) a step of selecting each of the above arithmetic expressions according to the inputted basic specifications, divided into arithmetic expressions for performing short-circuit transfer welding. The welding condition setting method according to claim 9 which is dependent on claim 2, (a) calculates a penetration depth from a set welding voltage, a set welding current, and a set welding speed,
(B) a current command parameter and a 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 between the upper limit penetration depth and the lower limit penetration depth, and if the welding speed is not input as a basic specification, the set welding current is corrected. (D) When the welding speed is input as the basic specification, the welding speed is corrected and the welding current is recalculated accordingly.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an arc welding apparatus and a method for setting welding conditions of 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, referred to as a welding torch).
An articulated robot 2 holding a torch 1, a welding power supply 3 for supplying power to the tip 16 at the tip of the torch based on the welding power output of the output terminals 3 a and 3 b, a current I and a voltage V of the welding power output Command parameters P _I , P instructing the welding power source 3 to output
A welding controller 4 for automatically setting _V and sending the respective command signals i and v, a robot controller 5 for controlling the articulated robot 2 based on teaching data TD including a welding speed command signal, and a drum 6 It comprises a wire feeding device 8 for feeding the filled wire 7 as a consumable electrode to the torch 1 and a jig 9 on which a welded product 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 based on the welding speed.

The wire feeding device 8 mounted on the articulated robot 2 includes a bending straightener 11 and an encoder 1
2. A pair of feed rollers 13a, 13 holding the wire 7
b, a rotary actuator 14 for driving the rollers 13a and 13b, and a torch cable 1a for guiding the wire 7 to the torch 1. The wire 7 is made to protrude from the tip 16 in the nozzle portion 15 of the torch 1.
The rotary actuator 14 is controlled by a drive signal having a feed rate proportional to the magnitude (average value) of the welding current i from the welding controller 4 to feed out the wire 7, and the detection wire feed at that time is sent out. feed rate MR _a is sent to the welding controller 4 from the encoder 12.

The welding controller 4 performs automatic setting of welding conditions (current, voltage and speed) and automatic correction of welding conditions for disturbance, and FIG. 2 conceptually shows the hardware. Thus, the joint shape, posture, welding method (spray transfer type and short-circuit transfer type in the case of pulse and mag welding), leg length L, tip base material distance EXT (tip 16 and base material distance), 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 which are input for every N joints in one product, for example. Initial condition setting means 42 for determining welding conditions from the basic specifications by calculation, an arithmetic expression memory 43 storing arithmetic expressions used for calculation of the initial condition setting means 42, and an 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 condition automatic management correction means 44 for setting P _I ′ and 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
The A / A converter converts the current into a current command signal i and a voltage command signal v in analog form, which are input to the welding power source 3 and command the current and voltage to be derived from the output terminals 3a and 3b. Also, 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 modified current command parameter P _I 'relationship between the welding current I and the initial voltage command parameter P _V and the corrected voltage command parameter P _V' relationship between the welding voltage V is the welding power source 3
Are set in a relationship in which the characteristics of the above are corrected. That is, the current command parameters P _I , P _I ′ and the voltage command parameters P _V , 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 control device having a teaching data memory for each joint.
Reads the data of each memory in sequence and
, And each time one memory is read, a condition calling signal 5a is sent to the welding controller 4 to access the condition file 45. As a result, in synchronization with the teaching data TD, the welding conditions (P _I , P
_V , I, V and welding speed WS) are read out.

The set of arithmetic expressions stored in the arithmetic expression memory 43 is obtained in advance by experiments. Further, the arc ON / OFF signal indicating stop the welding start and is sent to the robot controller 5 by Ri溶 contact controller 4. The arc welding apparatus of the present invention is configured as shown in FIG.
The welding controller 4 receives the condition calling signal 5a from the robot controller 5 and executes the program relating to the welding process performed in cooperation with the teaching data of the robot controller 5. It is running at 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 a welding unique to a product maker without relying on the robot maker. Further, since the welding controller 4 is separated from the robot controller 5, the welding controller 4 does not participate in the control relating to the motion of the robot at all, 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 for it, resulting in a very versatile welding management system.

Next, how the welding controller 4 sets 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 consisting of steps S ₁ [input basic specifications] and step S ₂ [automatic setting of optimum welding conditions], step S ₄ [start of actual welding], and 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 This is the 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,
Since the automatic management when there is this gap and the processing in the main welding do not directly relate to the present invention, the description is omitted.

According to the welding condition setting method of the present invention, the above-mentioned step S ₂ , that is, the setting of the leg length (determination of single layer or multi layer) and the subsequent automatic setting of the welding speed (in the case where the welding speed is not inputted). For each of the cases where welding conditions are set) and where the welding speed is manually set (welding conditions when the welding speed is input), the condition setting for pulse welding and the spray transfer type welding in mag welding It is characterized by the condition setting when performing and the condition setting when performing short-circuit transfer type welding in mag welding.

[0025] Now, basic specification input step S ₁ is a process at the beginning of FIG. 4, the joint shape, orientation, welding speed WS, leg length L, the chip base distance EXT, thickness t, except fillet input the welding cross sectional area a _1, the penetration depth magnitude boundary constants K ₈₆ and the minimum penetration depth ensures constant K _87. This input is made by an operator's key operation. After the input of the leg length setting basic specifications, in step _S201 [joint shape = semi-thin], it is determined whether the joint shape is a semi-thin weld or another type of welding (for example, butt welding). If the joint shape is a fillet weld, step S ₂₀₄ [L ≦ 5] → step S ₂₀₅ [L =
L + K ₁₄₂ ] → S ₂₀₆ [Semi-wall cross section A = (1/2) L
² ] is calculated. In the calculation of the cross-sectional area of the meat, first, when the designated leg length is 5 mm or less, the constant K
₁₄₂ (for example, 0.5 mm) is added to make the leg length longer ( _S204 → _S205 ). Then, when the leg length is determined, the section thickness A of the meat wall is calculated in step _S206 .

The next process performed by the welding controller 4 is to determine whether welding that does not cause a defect in the shape of the deposited metal at the current leg length is possible with a single layer or a multilayer layer (here, two layers) depending on the welding posture. It is determined by calculating the above. That is, first, in step _S207 [posture = downward], it is determined whether the welding posture is downward or other than downward (having an angle). If the joint posture is downward, step S ₂₀₈ [L ≦ K
₁₃₇ ] and the current leg length and a constant K ₁₃₇ (for example, 10 m
m]. As a result, in the case of L ≦ K _137, (so that the leg at this stage is finally set) is determined that possible weld which does not cause more servings shape defects in the current leg proceeds to the next process, L > _K137 , step S ₂₁₀ [L
≦ K ₁₃₈ ].

In step _S210 , the current leg length and the constant K
₁₃₈ (for example, 15 mm). The constant K ₁₃₈ is a leg length value that allows two layers to be formed without causing a shape defect when the posture is downward, and when L ≦ K ₁₃₈ (the shape defect is detected with the current leg length). Step S)
_{212 to} S ₂₁₅ [Teaching point change calculation command]
If L> K ₁₃₈ , it is determined that welding that does not cause a shape defect with the current leg length is difficult even with a two-layer pile, and step S
_{At 211} , the display indicates that the leg is over.

The instruction to change the teaching point is:
Since the initial teaching point is assumed to have a further height, the throat thickness r is calculated from the cross-sectional area A calculated in step S206, and the teaching point is corrected by this value in order to keep the distance between the chip base materials constant. Is suggested by the display. If the joint posture is other than downward at step S207, step S216 [L ≦ K13
5], the current leg length L and the constant K135 (for example, 8 mm)
Compare with The constant K135 is the maximum leg length value that can be further raised without causing a shape defect when the posture is not downward. If welding is possible in step S216, the process proceeds to the next process. If a shape defect occurs, step S217 [L ≦ K
136]. The constant K136 (for example, 12 mm) is a leg length value capable of forming two layers without causing a shape defect when the posture is not downward. Each constant K135 ～K138, since the weight and surface tension of the molten metal by fillet sectional area is involved, has been determined experimentally.

[0029] by leg length correction and calculation and more servings or multilayer prime or determination process of welding the cross-sectional area of the steps S ₂₀₄ to S _206, to ensure proper leg length respect to the joint shape and the orientation specified by the operator, welding Automatic setting with guaranteed strength becomes possible. However, if the joint geometry of the weld other than fillet weld, the welding cross sectional area A and A ₁ at the time of basic specifications input proceeds to step S _202, the next step S ₂₀₃
After setting the designated 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 in the case where the welding speed WS is designated by the basic specification input. In the case of other than the welding of the meat meat, the process automatically proceeds to the welding speed manual setting algorithm. If you do not specify a welding speed in the basic specification input, WS in step S ₂₀₉ after
Judgment is automatic, and the welding speed is calculated in a later process.

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

Therefore, the following condition is 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]

[Number 1] _{I mAX = K 19 · L +} K 20 ( For L ≦ 7)

[0033]

[Number 2] _{I mAX = K 21 · L +} K 22 (L> case 7)

[0034]

Equation 3] _{WS mAX = -K 102 · L +} K 103 ( For L ≦ 5)

[0035]

## _EQU4 ## WS _mAX = −K ₂₃ · L + K ₂₄ (5 <L <10
Then, I _MAXX determined from Expression 1 or 2 is substituted into MR = f (I, EXT), and the obtained MR is related to the relational expression MR = f (L, W
By substituting into S), the welding speed WS can be calculated.
Further, the welding speed WS is compared with WS _mAX obtained by Expression 3 or 4. If WS is equal to or less than WS _mAX , WS and I _MAXX at that time are the welding speed and welding current obtained.
If WS> WS _mAX , the calculation is repeated with the welding current reduced until WS ≦ WS _mAX, and the welding speed and welding current are obtained when the same condition is satisfied.

The calculation of the welding speed and the welding current is performed in step S ₂₁₉ [L ≦ 7] in FIG.
→ determine the upper limit current value at step S ₂₂₀ and step S ₂₁₉ → Step S _221, after pulse welding or MAG welding or the determination process (step S _230), step S ₂₃₁ of FIG. 5 in the case of pulse welding [MR = f (I, EXT)] → Step S
₂₃₂ [Calculation of welding speed WS] → Step _S233 [L ≦
5] → Step _S235 and Step _S233 → Step S
_In the case of mag welding at step ₂₃₄ , step S ₂₅₁ [M
R = f (I, EXT)] → Step _S252 [Welding speed W
S calculation] → Step S ₂₅₃ [L ≦ 5] → Step S
₂₅₄ and step _S253 → The upper limit speed value is obtained in step _S255 . Then, the obtained welding speed is WS> WS _mAX
Is determined in step _S236 in the case of pulse welding,
In the case of mag welding, it is determined in step _S256 that WS> WS
_If it is determined to be _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 calculation of the welding speed is repeated by gradually reducing the welding current. Thus, even when the welding speed is not input, the welding current and the welding speed can be calculated.

Setting of welding voltage The concept of the 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 "in principle, the amount of spatter generation can be extremely reduced"
As shown in the characteristic diagram of FIG. 1, at the boundary of short-circuit / non-short-circuit where both short-circuit type spatter that occurs frequently when the arc length is short and non-short type spatter that occurs when the arc length is long decrease.
It is optimal to find the balance of welding voltage to welding current. This also limits the maximum arc length, and effectively acts to prevent undercuts and improve bead appearance.

Therefore, the number of short circuits is several (for example, 1 / s).
FIG. 12 shows the relationship between the current and the voltage at the boundary between the short circuit and the non-short circuit by performing feedback control of the voltage for each current so as to be near ec). As shown in the 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 mainly due to an increase in the voltage drop _VL at the wire protrusion due to an increase in the current, an increase in the potential gradient (voltage drop per unit length of the arc length) due to an increase in the plasma flow with the increase in the current, and melting of the tip of the wire with the increase in the current It is conceivable that the sharpening occurs, the arc length increases, and the arc voltage _VA increases.

In FIG. 12, the slope of the straight line is small on the low current side, and is large on the high current side. This is considered to be because the above-mentioned 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 shows that the voltage at the boundary between the short circuit and the non-short circuit for each current increases as the distance increases to 5 mm. It is considered that this is because the increase in the voltage drop _VL at the wire protrusion due to the increase in EXT and the increase in the arc length due to the sharpening of the tip of the wire due to the increase in the resistance heating are superimposed.

As described above, it has been found that the welding voltage in the case of pulse welding exists at the boundary between short-circuit and non-short-circuit, and is expressed by two functions of the welding current and EXT as shown in FIG. Therefore, the data of FIG. 12 is subjected to multiple regression analysis to express the welding voltage as a function of the welding current and EXT, and the following equation is obtained.

[0041]

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

[0042]

[Formula 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, when 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 is smaller than I _Cr, it follows that the voltage at the boundary between short-circuit / non-short-circuit which fluctuates due to the welding current. Therefore, it can be determined as a more optimal welding voltage.

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
Compare with _Cr . If it is determined in step _S239 that the current is on the high current side, the process proceeds to step _S240 in which the operation of expression 5 is performed.
Proceed to ₂₄₁ . The welding controller 4 thus sets the welding voltage V.

When welding is performed when the welding voltage at the time of the arc start is set slightly higher than the short-circuit / non-short-circuit boundary and when the welding voltage is set lower than the short-circuit / non-short-circuit boundary, as shown in FIGS. Voltage is slightly lower (Fig. 1
The method 4) has many short circuits at the start of welding and has a considerably large amount of spatter. On the other hand, when the voltage at the time of arc start is set slightly higher (FIG. 13), almost no short circuit is observed at the start of welding, and the start of welding without spatter generation is achieved. For the above reasons, it is preferable that the set welding voltage at the start of welding be slightly higher than the short / non-short boundary.

On the other hand, the setting of the welding voltage in the case of the mag welding is started by first determining in step ₂₅₈ [spray] in FIG. 6 whether to perform the spray transfer type welding or the short-circuit transfer type welding. Which welding is performed is set by the operator for each joint when the basic specifications are input. In the case of this mag welding,
The arithmetic expression of the welding voltage uses a formula expressed by a polynomial of the welding current and the EXT. Step S ₂₅₉ when performing spray transfer type welding _{[V = K 77 · I + K} 78 · EXT +
K ₇₉ ], and when performing short-circuit transfer welding, step S
Proceeds to _{260 [V = K 74 · I + K} 75 · EXT + K 76 ]. The difference between the arithmetic expressions is mainly that the constants K ₇₉ and K ₇₆ of the coefficient terms are different, and K ₇₉ > K ₇₆ .

Welding current and welding current depending on penetration depth P
The calculation of the set welding current I, the set welding speed V, and the set welding voltage WS is temporarily completed by the above correction. However, in the present invention, in the case of both pulse welding and mag welding, the penetration depth is higher than that of I, V, WS. Is calculated (steps S ₂₄₂ and S
₂₆₁ ). Based on the result, it is determined in 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] → S ₂₆₅ [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 It is the upper limit penetration depth of the case. Further, the K ₈₇ · t in step S ₂₄₆ limit the penetration depth in the case of pulse welding, the K ₈₉ · t in step S ₂₆₅ is a lower 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 Step S
Return to step ₂₃₁ (in the case of MAG welding, step _S251 ). Also,
If the result P is less than the lower limit penetration depth, step S ₂₄₇ and increments the amount of current (step S ₂₆₆ in MAG welding), step S ₂₃₁ so as to re-calculating the welding speed or the like and current obtained by the increase It returns to (step _S251 ). When the operation result P is between the upper limit penetration depth and lower penetration depth, step S ₂₄₈ [P _V = K ₁₄ · V-
K _15] computes a voltage command parameter P _V by (in the case of MAG welding step S _267), the following step S ₂₄₉ [P
_I = K ₁₂ × 10 ^-3 · L ² · WS-K ₁₃ ] (Step S ₂₆₈ [P _I = K ₈₀ × 10 ^-3 · L ² · WS-
K ₈₁ ]) to calculate the current command parameter P _I.

[0048] Thus, current I, voltage V, the speed WS and the current command parameter P _I, the voltage command parameter P _V,
Welding controller by setting process in step S ₂₅₀ 4
Stored in the condition file 45 of the inner, the command parameter P _I, P _V is the command signal i, the start of the welding with a v is sent for each joint to welding power source 3. Here, an arithmetic expression for obtaining the current command parameter P _I (steps S ₂₄₉ , S
Arithmetic expression used in ₂₆₈₎ may be calculated by arithmetic expression same form as the voltage command parameter P _V, in the welding controller 4, without using the welding current I, leg length L and the welding speed WS
Is a function (P _I = a × 10 ⁻³ · L ² · WS-b) which can be derived from a purely geometrical method using as a variable.
This is because if PI = f (I, EXT), an experimental error in obtaining this relationship is included, and if the arc length between the experiment and the actual welding is slightly different, this relationship changes. represent the current command parameter P _I as a function of the welding current I and the chip base distance EXT are those considered to be inappropriate. As described above, the arithmetic expression for obtaining the current command parameter P _I in the main welding controller 4 is based only on the geometrical conditions, so that a strict wire feed amount for obtaining the target leg length L is ensured. Become.

The welding condition setting of the welding condition setting than in the case of welding speed WS is input is to determine the set welding speed when the basic specifications input by the calculation when the welding speed is not specified by the operator. However, there is also need to specify the welding speed from a relationship such as cycle time, the welding controller 4 in this case, the welding speed manual setting algorithm shown in FIG. 7 or 8 is determined in step S209 [WS Auto] move on. The welding speed manual setting algorithm calculates the set welding current I and the set welding voltage V based on the input welding speed. The present welding controller 4 calculates the even converted leg length when the welding other than fillet (step S202,
After S203), the process proceeds to the welding speed manual setting algorithm.

Even with this welding speed manual setting algorithm,
The arithmetic expression for obtaining the current command parameter PI is the same as when the welding speed is not input, and the leg length L and the input welding speed WS
(PI = a × 10)
-3 · L2 · WS-b) (step S271)
(Pulse welding), Step S291 (mag welding)). Next, in the welding speed manual setting algorithm, the set welding current I is calculated from the current command parameter PI (Step S).
272 (pulse welding), step S292 (mag welding).

Step S for subsequent pulse welding
₂₇₃[K₈₂≤I≤K₈₃] → Step S_{275 ー}[I> K₈₃]
And step S for MAG welding₂₉₃[K₈₄≤I≤
K₈₅] → Step S₂₉₅[I> K₈₅In the previous step
The welding current obtained in the step 3
The input welding speed WS is corrected according to whether it exceeds
Step S in contact₂₇₆Or step S₂₇₇, Mug melting
Step S in contact₂₉₆Or step S₂₉₇To)
It is determined whether to proceed to the next process. And
If the input welding speed WS is corrected, the corrected welding speed
Again, the welding current I and the current command parameter P_IIs calculated again
And repeat the setting of the set welding current. Where the constant K ₈₂Is
Current output range in welding power source 3 in pulse welding mode
Lower value, constant K₈₃Is the same upper value, constant K₈₄Is a mag welding module
Lower value of current output range in welding power source 3 during
Number K₈₅Is the same upper value.

Next, in the case of pulse welding, when the welding speed, welding current and current command parameters are set, the process proceeds to step S ₂₇₈ [I ≧ I _Cr ] in the same manner as the process in which the welding speed is not input.
To determine whether to use the high-current-side voltage calculation equation (Equation 5) or the low-current-side voltage calculation equation (Equation 6). Set the welding voltage in each case. After the setting of the welding voltage, the calculation of step S ₂₈₁ [calculation of penetration depth P] is performed, and the following 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 between the upper limit penetration depth and the lower limit penetration depth. If the operation value P is out of the range, the process proceeds to step S ₂₈₃ [WS = WS−1] or step S _283.
285 [WS = WS + 1], the welding speed is corrected, and the welding speed after the correction is returned to the calculation of the welding current and the current command parameter again. If the calculated value P is within the same range, the process proceeds to step S
₂₈₆ [P _V = K ₁₄ · V−K ₁₅ ] and the voltage command parameter P _V from the set welding voltage V (the 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, at 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.
To the welding power source 3.

Next, in the case of mag welding, when the welding speed, welding current and current command parameters are set, similar to the process in which the welding speed is not input, in step ₂₉₄ [spray], spray transfer welding is performed or short-circuit transfer is performed. It is determined whether mold welding is to be performed, and in the case of specification input of spray transfer type welding, a step S using the same voltage calculation formula as step _{S259 in} FIG.
FIG. 6 shows a case in which the arithmetic processing of ₂₉₉ is performed and short-circuit transition type welding is performed.
Step S using the same voltage calculation equation as step S ₂₆₀
Perform ₂₉₈ arithmetic processing.

When the set welding voltage is determined by the above calculation processing, the same as in the case of pulse welding, step S is performed.
₃₀₀ [Calculation of penetration depth P] is performed, and the following step _S301 [P < _K88 · t] → step _S303 [P ≧ _K89
In [t], the calculated value P of the penetration depth is determined, and if the calculated value P is out of the same range, step S ₃₀₂ [WS
= WS-1] or step S ₃₀₄ [WS = WS +
The welding speed is corrected by 1], return to operation again welding current and the current command parameter welding speed after correction, if the calculated value P is in the same range, ₉₇ step S ₃₀₅ [P _V = K
V-K ₉₈ ] to set the voltage command parameter P from the set welding voltage V.
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 weld controller 4 by setting process in step S _250.

Other Embodiments As another embodiment of the present invention, for example, when the welding speed is not input as the above basic specification, the method of setting the welding current and the welding speed is determined by the upper limit of the welding current and the welding speed determined by the leg length. Is calculated, and the calculated upper limit speed value is set to MR = f
(L, WS) and the wire feed speed determined by MR =
The calculated welding current is calculated by substituting the calculated welding current into f (I, EXT). When the calculated welding current is equal to or less than 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 reduced, and the calculated welding current is recalculated based on the reduced speed value. The calculation may be repeated to determine the set welding current and the set welding current.

As a method of setting the welding current and the welding speed when not input as the basic specifications, any representative value is determined from the upper and lower limits of the welding current and the welding speed for each leg length, and these representative current values or representative speed values are set. In the same manner, the wire feed speed obtained by the above equation is expressed by the relational expression MR = f (I, EXT) or MR.
= F (L, WS) to set the welding speed and welding current. In the embodiment, the reason why the upper limit current value and the upper limit speed value are set as conditions is that, for example, if the calculation is performed using the lower limit value, it is considered that the calculation speed requires time.

Next, the invention of a method for setting welding conditions of an arc welding apparatus may be applied to a control device storing both a welding program and a robot program. In other words, the control device in this case is implemented as a welding robot controller that controls a welding torch and a robot (a configuration in which a robot controller and a welding controller that controls a 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 outside 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. And the set welding current is reset.
According to this, even if the welding power source changes, an appropriate welding current corresponding to the welding power source can be automatically set.

[0059]

As described above, according to the first aspect of the present invention, the control device for controlling the arc welding is separated into a welding controller for controlling the welding process and a robot controller for controlling the motion of the robot. The welding controller can control the welding process only by communicating the timing of calling the condition from the robot controller.Therefore, without intervening in the robot controller's program, a program for setting and managing the welding conditions only in the welding controller is accumulated, Welding conditions unique to the product and welding conditions that ensure quality can be freely set without relying on robot manufacturer's programs that emphasize performance.

According to the invention of claims 2 to 10, welding conditions are automatically calculated based on the basic specifications inputted for each joint, so that even inexperienced persons can specify basic welding conditions specified in the design drawings. Just by inputting the specifications, appropriate welding conditions can be set. In particular, in the aspect of the third aspect, whether the weld metal is a single layer or a multilayer is automatically determined, so that the weld metal can be prevented from being defective in shape, and the operator can give a command for changing the teaching point or an instruction for over-leg length in advance. (Before welding).

According to the fourth aspect, even when the welding speed is not input as the basic specification, the welding current and the welding speed are determined 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. Can be calculated. According to the aspect of claim 5, since the current command parameter and the set welding current are calculated using a polynomial that can be derived from a purely geometric method using only the leg length and the input welding speed, the target is set regardless of the variation in the arc length. Strict amount of wire feeding for obtaining the leg length is secured.

According to the sixth aspect, since the welding voltage is calculated by the polynomial of the welding current and the distance between the chip base materials, the optimum welding voltage can be set for an arbitrary distance between the chip base materials. . According to the aspect of claim 7, when the welding voltage is calculated in the pulse welding, a boundary current corresponding to the distance between the chip base materials at which the characteristics of the polynomial changes is calculated, and a higher current side and a lower current than the boundary current are calculated. The above-mentioned polynomial is different from that on the other side, so that the short-circuit /
Since the voltage at the boundary of the V short-circuit is followed, 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 arithmetic expressions are used for performing the spray transfer type welding and the short circuit transfer type welding on the above polynomial. The welding voltage at the time of mold welding and short-circuit transfer welding can be set appropriately.
According to the aspect of claim 9, whether the penetration depth is between the upper limit penetration depth and the lower limit penetration depth according to the plate thickness is determined in advance, and the penetration depth is poor. The welding conditions once set can be corrected to secure an appropriate penetration depth.

[Brief description of the drawings]

FIG. 1 is an explanatory view 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 of the entire welding condition setting 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 illustrating a welding condition setting method in pulse welding when a welding speed is input.

FIG. 8 is a flowchart illustrating a welding condition setting method in mag welding when a welding speed is input.

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

FIG. 10 shows the characteristic of the upper limit speed value for each leg length, 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 generated and the number of short circuits in pulse welding. The characteristics indicated by the dotted line and the solid line are measured using different shielding gases.

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

FIG. 13 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 higher than the boundary of short-circuit / non-short-circuit.

FIG. 14 is a measurement diagram in which a short circuit condition is recorded when the welding voltage at the time of arc start is set slightly lower than the boundary between short circuit and 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 the distance between the chip base materials, I is the welding current, V is the welding voltage, MR is the wire feed speed, WS is the welding speed, i Is a current command signal, v is a voltage command signal,
In the respective drawings, the same elements are denoted by common reference numerals.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification symbol FI B23K 9/127 509 B23K 9/127 509D (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 9/095 B23K 9 / 09 B23K 9/12 B23K 9/127

Claims (9)

(57) [Claims] 1. A robot that holds a welding torch to which a wire is fed and steers the welding torch according to teaching data, a welding power source that outputs current and voltage to the welding torch, a joint shape of a joint to be welded, Joint posture, welding
The basic specifications including the method, leg length, distance between chip base materials, and plate thickness
By inputting and calculating, it is output from the above welding power source.
From the above current and voltage command parameters and welding speed
Calculated welding conditions and store them in the condition file.
In transmitting the teaching data to the robot 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 synchronized with the transmission timing of the teaching data. ; and a robot controller for commanding the condition calls timing to said welding controller, freely change the robot and the welding power supply
An arc welding apparatus characterized by being able to cope with the problem . 2. A teaching data and a signal indicating a welding speed are sent to a robot holding a welding torch from which a wire is sent, and current and voltage command parameters are commanded to a welding power supply for feeding the welding torch. A welding condition setting method for setting welding conditions including the command parameters and the welding speed for each welded joint of each product, comprising: a joint shape, a joint posture, a welding method, a leg length, and a distance between tip base materials.
Enter the basic specifications, including separation and plate thickness, for each joint of each product.
Single or multiple layers based on basic specifications
Set the number of welding layers, welding current and welding voltage by calculation
Each of the above currents and voltages with the characteristics of the welding power source corrected together with
A method for setting welding conditions for an arc welding apparatus, wherein command parameters are set by calculation . 3. A method for setting the number of welding layers based on the basic specification, comprising: calculating a welding cross-sectional area from an input designated leg length; and welding the molten welding section from the welding cross-sectional area and a welding posture given by the input. Judge whether the shape of the metal is good, if it is judged that the shape is good, set a single layer with the specified leg length, and if it is judged that the shape is bad, set the leg length of the multi-layered heap and instruct to change the teaching point, 3. The welding condition setting method for an arc welding apparatus according to claim 2, wherein an instruction to exceed the leg length is issued when it is determined that the shape is not sufficient even with the leg length of the multilayer building. 4. A method for setting a welding current and a welding speed based on the basic specifications when a welding speed is not input as the basic specifications, the method includes: a wire feeding speed, a welding current, and a wire feeding speed and a welding speed. The welding current and welding speed conditions provisionally determined from the leg length are added to the relational expression, and the welding current and welding when the wire feeding speed based on the provisionally determined welding current and welding speed satisfy each of the above relational expressions are both satisfied. 3. The method according to claim 2, wherein the speed is a set welding current and a set welding speed. 5. The method according to claim 2, wherein the method for setting the current command parameter based on the basic specification includes calculating the current command parameter using a polynomial expression including a function of a leg length and a welding speed. How to set welding conditions for welding equipment. 6. A method for setting a welding voltage based on the basic specification, wherein the welding voltage is calculated by a polynomial comprising a function of a welding current and a distance between a chip base material, and the set welding voltage is calculated based on the polynomial. 3. The method for setting welding conditions for an arc welding apparatus according to claim 2, wherein: 7. In the case of pulse welding, the above polynomial is divided into two arithmetic expressions on the high current side and the low current side from the boundary current according to the distance between the chip base materials, and when the set welding current is larger than the boundary current, 7. The set welding voltage according to claim 6, wherein the set welding voltage is calculated from the high current side calculation formula, and when the welding current is smaller than the boundary current, the set welding voltage is calculated from the low current side calculation formula. Method for setting welding conditions for arc welding equipment. 8. In the case of mag welding, the above polynomial is divided into an arithmetic expression for performing the spray transfer type welding and an arithmetic expression for performing the short-circuit transfer type welding, and each of the above-mentioned arithmetic expressions is selected according to the input basic specifications. 7. The method for setting welding conditions for an arc welding apparatus according to claim 6, wherein: 9. A penetration depth is calculated from the set welding voltage, the set welding current and the set welding speed, and the penetration depth is between an upper limit penetration depth and a lower limit penetration depth according to the plate thickness. In the case of the above, the current command parameter and the 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. 7. The arc welding according to claim 2, wherein the set welding current is corrected when the welding speed is not input as the basic specification, and the welding speed is corrected when the welding speed is input as the basic specification. How to set welding conditions for equipment.