KR20010002952A - Optimum fill area control method according to variation of groove area by using constant voltage characteristic - Google Patents

Abstract

PURPOSE: An automatic control method for the optimal deposition rate to the change of a welding portion by using a characteristic of a constant voltage is provided to control a necessary deposition rate by corresponding to a real time zone to the welding portion processing and assembling error of a welded material. CONSTITUTION: A standard deposition rate to a standard groove is set. The dimension of an actual groove(9) is measured by a square sensor(8). A comparator(3) compares the dimension of the set standard groove(1) with the actually measured groove and inputs a compensating signal to a controller(6). The welding current and voltage of welding equipment(7) are regulated by the inputted signal. The welding current and voltage and a wire feeding speed(12) are measured and compensated in the comparator. Then, the measured conditions are automatically controlled to the optimal welding conditions within the real time.

Description

Automatic fill method for welding area improvement using constant voltage characteristics {Optimum fill area control method according to variation of groove area by using constant voltage characteristic}

The present invention relates to a method for automatically controlling the optimum welding amount for the change of the welded cross-sectional area using the constant voltage characteristics. The present invention relates to an automatic control method of optimum deposition amount for.

In general, welding techniques used in industrial sites are classified into welding, pressing and soldering. When the welding method which is most widely used in shipbuilding or steel structure manufacturing process is subdivided, it is classified into consumables in which the electrodes are consumed and non-consumables in which the electrodes are not consumed. In addition, such consumable welding methods include shield metal arc welding, gas metal arc welding, and submerged arc welding, each of which is unique. It is classified as semi-automatic or automatic welding according to the method and usage, and depending on the number of electrodes to be welded at the same time, Single or Multi, that is, 1 electrode, 2 electrodes, 3 electrodes ... welding Classified as

The gas metal arc welding generates an arc between the electrode and the base material by applying a welding current and voltage to the electrode continuously mechanically supplied, and then activates or inerts a protective gas around the welding pool to protect the welding portion and the metal. It is a welding technique performed by continuously supplying the metal, and the current / voltage used is low, the welding rod diameter, the weld metal, and the penetration are small.

The submerged arc welding method is a method of welding an object to be welded by heat generated by generating an arc between a welding rod and a base material under a granular flux. Because of the high current and voltage, high welding rod diameter, welding metal and penetration, it is especially applicable to high efficiency welding of thick plates.

Conventionally, when welding a steel structure to be welded by using the submerged arc welding method as described above, that is, joining two joints by joining two or more iron plates in a plane, right angle, diagonal or any other shape, such joints The part (welded part improved surface) is chamfered into I type, V type, X type, Y type, etc. to increase the welding strength. However, such a welding improved surface cannot obtain a sound welding result due to machining errors during chamfering or assembling errors generated during mounting, and there is a problem that a welder must continuously monitor and adjust welding parameters during welding.

The present invention has been made in consideration of the above problems, and an object thereof is to automatically adjust an optimum welding amount for a weld area improvement cross-sectional area that can control a required welding metal amount corresponding to a real-time band for welding process and assembly error of a welded part. It is to provide a control method.

In the multi-electrode submerged arc automatic welding, a first step of setting a standard deposition amount (standard groove area) to a standard groove, a second step of measuring the actual groove area by a visual sensor, A third step of inputting a correction signal to the control unit by comparing the set standard groove area with the actual measured groove area in a comparison unit, and adjusting the welding current and voltage of the welding equipment by the input signal; Optimal welding amount for welded area improvement cross-sectional area change by using constant voltage characteristic to automatically control to the optimum welding condition in real time by measuring the welding current, voltage and wire feeding speed of the welding equipment and re-input and correction to the comparator. An automatic control method is provided.

1 is a block diagram showing a configuration according to the present invention

2 is an exemplary view showing a wire melting rate and a current relationship

Figure 3 is an exemplary view showing the bead shape of the V-groove

* Explanation of symbols for the main parts of the drawings

(1): Standard groove area setting value (2): Actual groove area measurement value

(3): comparator (4): current correction signal

(5): Voltage correction signal (6): Control part

(7): Welding equipment (8): Vision sensor

(9): Actual groove (10): Current value measured in welding equipment

(11): Voltage value measured at welding equipment

(12): Wire feed rate value measured in welding equipment

1 is a block diagram showing a configuration according to the present invention, Figure 2 shows an exemplary view showing a wire melting rate and a current relationship, the present invention is welded by the constant voltage welder characteristics as shown in FIG. It uses the principle that it is proportional to the current, that is, the wire feeding speed. In the case of using the constant voltage characteristic, the wire feeding speed is controlled differently according to the arc voltage or the welding current value. That is, the wire feeding speed is affected by the combined value of the arc voltage and the welding current, and can be expressed as follows.

Integrating with

Formula (1)

ΔI = I (t + Δt) -I (t): current difference between current and previous measured values

ΔV = V (t + Δt) -V (t): difference between the current measured voltage and the previously measured voltage value

WFS: Wire feed speed

△ WFS: Wire Feed Speed Change

I (t + Δt), ~ V (t + Δt): Current measured current and voltage

I (t), ~ V (t): previously measured current and voltage

: Value determined by experiment

That is, when the value of ΔWFS is determined, the voltage and current values to be controlled are automatically determined. Therefore, when the value of ΔWFS is converted into an area value to be filled in the groove, the voltage and current values can be controlled.

3 is an exemplary view showing the bead shape of the V-groove, wherein the bead of the V-groove is the groove area (Ag) and the cap area ( ) In the present invention, the measurement area of the groove to be actually filled using the visual sensor is expressed as A_fm, the standard area for the standard groove A_fs, and the area difference to be compensated by ΔA and expressed as follows.

ΔA = A_fs-A_fm

A_fs: standard area

Ag_s: Standard Groove Area

: Standard Cap Area

A_fm: measuring area

Ag_m: Measuring groove area

: Measuring cap area

In addition, if the area actually filled in the groove is represented by the wire feed rate (WFS) and the wire diameter (D),

Because of,

Dividing this by the velocity gives the area filled per unit velocity. Here, η represents efficiency and η 1.

In other words, the measurement area A_fm and the standard area A_fs are represented by the wire feed rate, the wire diameter and the speed as follows.

WFS ': Wire feed rate to fill the actual measured area (mm / min)

WFS_s: Wire feeding speed to fill standard area (mm / min)

V_s: Welding speed (mm / min)

Therefore, the difference between the amount to be filled in the standard groove and the amount to be filled in the actually measured groove, that is, the area difference is as follows.

Therefore, to summarize this with respect to the wire feed speed change,

Formula (2)

As described above, since DELTA WFS is converted into an area value to be filled in the groove, voltage and current values can be controlled. That is, substituting Equation (2) into Equation (1) determines the control value of the voltage and current for each torch. In the case of the 5-electrode automatic welding device, since the head torch is used to implement a constant penetration, it is necessary to control the remaining four electrodes except the head torch, and the control value for each torch considering the arc stability is as follows.

I_s2 ~, ~ I_s3 ~, ~ I_s4 ~, ~ I_s5: Standard welding condition to fill standard groove

The present invention is to automatically control the optimum deposition amount in consideration of the arc stability by the torch-specific control value as described above, first set the standard deposition amount (standard groove area) to the standard groove, the area of the actual groove by the visual sensor After the measurement, the preset standard groove area and the actual measured groove area are compared in the comparison unit, and the control unit adds the difference between the standard welding current / voltage and the current measured current / voltage and the standard welding current / voltage value. That is, a correction signal is input, and the controller in which the correction signal is input controls the amount of welding by adjusting the welding current and voltage of the welding equipment. At this time, the welding current and the voltage and the wire feed rate measured in the welding equipment are input to the comparator to select the actual welding current and voltage is corrected.

That is, the groove area measured by the visual sensor and the preset standard groove area are compared with each other in the comparison unit. If the groove area is different, the welding amount is automatically adjusted by increasing or decreasing current / voltage under standard welding conditions. have.

As described above, the present invention is configured to automatically adjust the current / voltage according to the comparison between the standard groove area and the actual groove area, to provide an optimal deposition amount in the multi-electrode submerged arc welding, and to optimize the welding according to the change of the groove cross-sectional area. There are many effects such as adaptive control of conditions, realization of high performance and automation of submerged welding.

Claims (1)

In multi-electrode submerged arc auto welding; The first step of setting the standard deposition amount (standard groove area) to the standard groove; A second step of measuring the area of the actual groove by a visual sensor; A third step of comparing the set standard groove area with the actual measured groove area by a comparison unit and inputting a correction signal to the control unit; A fourth step of adjusting the welding current and the voltage of the welding equipment by the input signal; The fifth step of measuring the welding current and the voltage and the wire feeding speed of the welding equipment to input and calibrate to the comparator to automatically control to the optimum welding conditions in real time for the improvement of the welded section using the constant voltage characteristics Automatic welding method for optimum deposition amount.