JPH0531580A - Semiautomatic arc welding machine - Google Patents

Abstract

PURPOSE:To make proper the distance between a tip and base metals by informing to a welding operator that the distance between the tip and the base metals during welding exceeds a proper range to allow the operator to correct the torch height by his own hand in semiautomatic arc welding. CONSTITUTION:The semiautomatic arc welding machine is provided with an arithmetic circuit 13 to calculate the wire extension and the arc length from detected values of a wire feed rate detector 10, a welding current detector 11 and a voltage detector 12 between the tip and the base metals, an arithmetic circuit 14 for the distance between the tip and the base metals, 8 deviation arithmetic circuit 15, a setting device 16 for the distance between the tip and the base metals, a comparator 17, a dead zone setting device 18 and a display device 19 and it is displayed on the display device 19 that the deviation between an arithmetic value and a set value of the distance between the tip and the base metals exceeds a dead zone set value range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-automatic arc welding machine having means for informing a welding operator of the necessity of correcting the welding torch height.

[0002]

2. Description of the Related Art Conventionally, in automatic arc welding in which a wire as a consumable electrode is constantly fed to a welding torch, and the operation of moving the arc along a welded joint while keeping the arc length constant is performed by a machine, wire protrusion If the length or the arc length changes, the welding conditions fluctuate and the welding result is adversely affected. Therefore, as shown in JP-B-63-45915 "Automatic control method for distance between tip and work piece", welding current, The tip-base metal voltage and wire feed speed are detected, the wire protrusion length and arc length are calculated from these detected values, and the welding torch position (torch height) is mechanically corrected based on this calculation result. By doing so, the wire protrusion length and the arc length are optimized.

On the other hand, in semi-automatic arc welding in which a welding operator holds a welding torch in his hand, there are many cases in which beginners perform welding recently due to lack of manpower, and conventional semi-automatic arc welding machines cannot perform stable welding. In particular, it is a problem that welding conditions fluctuate due to hand shake of the welding operator and the welding results are adversely affected.

In order to solve this problem, an up-and-down moving device equipped with a welding torch of an automatic arc welding machine for mechanically controlling the distance between the tip and the base metal as shown in the above-mentioned known example. When the welding operator holds in his hand to perform semi-automatic arc welding, the shaking of the operator's hand and the movement of the operator's hand to keep the distance between the tip and the base metal constant and the vertical movement with the welding torch attached Since the movement of the device is not synchronized, the distance between the tip and the base metal is not constant, and a good welding result cannot be obtained. That is, in semi-automatic arc welding in which the welding torch height is artificially determined, it is impossible to keep the distance between the tip and the base metal constant by mechanically controlling the welding torch height.

[0005]

As described above, the welding operator holds the welding torch in which the wire is continuously fed mechanically and moves the arc along the welded joint while keeping the arc length constant. In arc welding, how to optimize the wire protrusion length and the arc length is an issue so that even a beginner can perform stable welding as well as a skilled worker. Of these challenges,
It is considered that the constant arc length control can be realized by controlling the set welding current or the set welding voltage of the semi-automatic arc welder according to the deviation between the proper arc length determined by the welding conditions and the detected arc length during welding.

[0006] Therefore, the purpose of the present invention is artificially determined,
In order to optimize the distance between the tip and the base metal (sum of wire protrusion length and arc length), which is considered to be impossible to mechanically control,
If the distance between the tip and the base metal during welding exceeds the proper range,
It is an object of the present invention to provide a semi-automatic arc welder that informs the welding operator of this fact and enables the operator to correct the height of the welding torch by himself.

[0007]

In order to achieve the above object, the present invention provides a welding torch operated by a welding operator's hand and a wire feeding for feeding a wire while contacting the inner surface of the tip of the welding torch. In a semi-automatic arc welding machine equipped with a device, a welding power source that supplies electric power to the tip and the base metal, from the detected values of the welding current detector, the tip-base metal voltage detector, and the wire feed speed detector A calculation means for calculating the wire protrusion length and the arc length, and a tip-base metal distance calculation means for inputting the wire protrusion length and the arc length obtained by the above calculation and outputting the sum of them as the tip-base metal distance. , The tip-base metal distance set by the tip-base metal distance setting device according to the welding conditions and the output of this tip-base metal distance calculation means is input, and the deviation between the tip-base metal distance of both The bias to output A calculating means, a comparing means which receives an output of the deviation calculating means as an input, and outputs an operation signal when the input value exceeds a predetermined deviation range, and an operation signal which is operated by the operation signal from the comparing means, It is characterized by including a display device for notifying a welding operator that the distance between the tip and the base metal has exceeded an appropriate range.

The comparison means determines whether the deviation between the distance between the tip and the base material is positive or negative, and the display device determines whether the deviation is positive and exceeds a predetermined deviation range, or when the deviation is negative and the predetermined deviation range is exceeded. The feature is that it is displayed separately when it exceeds the limit.

[0009]

[Function] The welding current detector, tip-base metal voltage detector, and wire feed speed detector detect the welding current, tip-base metal voltage, and wire feed speed during semi-automatic arc welding, and detect these. The sum of the wire protrusion length and the arc length calculated by the calculation means using the value, that is, the calculated value of the distance between the tip and the base metal and the tip-base metal set by the tip-base metal distance setter according to the welding conditions. The deviation from the distance is calculated by the deviation calculation means, and this deviation value and the dead band width of the deviation value set by the dead zone setting device described later are taken into the comparison means, and the deviation value calculated is the dead zone set value (predetermined deviation range). ) Is exceeded, the display device is operated by the operation signal output from the comparison means to notify the welding operator that the distance between the tip and the base metal during welding has exceeded the proper range. As a result, the welding operator can correct the welding torch height with his or her own hand according to the contents displayed on the display device and maintain the distance between the tip and the base metal during welding to an appropriate value according to the welding conditions. Therefore, it is possible to prevent the occurrence of welding defects due to poor gas shielding and the interruption of welding work due to the welding of chips and wires.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The semi-automatic arc welding machine shown in FIG. 1 has a welding torch 1 having a gas discharge nozzle (not shown) for flowing a shield gas around a tip 2 and an arc 4, a wire feeding motor 8 and a feeding roller. The wire feeding device 9 and the welding power source 6 and the welding current / voltage controller 7 are mainly configured. For welding, the welding torch 1 is held by the welding operator in his / her hand and the feeding roller 9 connected to the motor 8 continuously feeds the wire 5 to the inner surface of the tip 2 to control the welding current / voltage. Electric power is supplied from the welding power source 6 to the tip 2 and the base metal 3 according to the welding conditions set in the vessel 7, and an arc 4 is generated between the wire 5 and the base metal 3 to melt the wire 5 and fuse it to the base metal 3. It is done by letting.

The names of the respective parts between the chip 2 and the base material 3 shown in FIG. 1 will be described with reference to FIG. In FIG. 2, the length of the wire 5 from the tip of the tip 2 to the arc 4 is the wire protrusion length LE, the length of the arc portion from the tip of the wire 5 to the surface of the base material 3 is the arc length LA, and the wire protrusion. The sum of the length LE and the arc length LA is the distance between the tip and the base metal. Also, in the figure, if the voltage drop of the wire protrusion length is VE, the arc voltage is VA, the tip-base metal voltage is V, and the welding current is I, the tip / base metal can be easily measured with a measuring instrument. The voltage V and the welding current I.

In the semi-automatic arc welding machine having the above-described structure, in order to keep the distance between the tip and the base metal at an appropriate value during semi-automatic arc welding performed by the welding operator holding the welding torch by hand, the wire protrusion during welding is required. You need to know the length and arc length. The wire protrusion length and arc length during welding are described in Guidebook "Sensing and Control in Arc Welding", Welding Society, Welding Method Research Committee, May, 1990, II-94.
~ II-99, welding current, tip
It can be obtained from the detected values of the voltage between base materials and the wire feeding speed by the following arithmetic expression.

(1) Calculation formula of wire protrusion length The wire protrusion length LE is calculated from the average current IA, the effective current IE, and the wire feeding speed v by the following equation.

[0015]

[Equation 1]

Here, k1 and k2 are constants.

(2) Calculation formula of arc length The arc length LA is calculated from the average current IA and the arc voltage VA by the following formula.

[0018]

[Equation 2]

Here, k3, k4, k5 and k6 are constants.

However, the arc voltage VA in the equation 2 cannot be measured, and the detected tip-base material voltage V, the resistance R of the wire protrusion length and the wire protrusion length obtained from the average current IA. The arc length LA is obtained by substituting the obtained arc voltage VA in the equation 2 from the voltage drop VE by the following arithmetic expression.

[0021]

[Equation 3]

[0022]

[Equation 4]

[0023]

[Equation 5]

Where α is the difference between the specific resistance and the specific heat temperature coefficient, β is the specific resistance temperature coefficient, C0 is the specific heat, η0 is the specific resistance, J is the work equivalent of heat, ρ is the specific gravity, and d is the wire diameter. , and the constants k7 is ^{k7 = 16αη0 / π 2 JρC0d 4} .

In FIG. 1, the wire feeding speed detector 10 such as a tachometer dynamo or the like connected to the feeding roller 9 or the wire feeding speed and the counter electromotive voltage of the motor 8 are substantially proportional to each other, and thus the motor 8 is used. A wire feeding speed with a back electromotive force detector (not shown) of the above, a welding current with a welding current detector 11 connected between the welding power source 6 and the base metal 3 or between the welding power source 6 and the tip 2, Further, the chip-base material voltage detector 12 connected between the chip 2 and the base material 3 detects the chip-base material voltage, and the detected values are calculated by the arithmetic circuit 13
The calculation circuit 13 calculates the average current and the effective current from the detected welding current and calculates the wire protrusion length and the arc length according to the equations 1 to 5. The wire protrusion length and the arc length obtained by the above calculation are taken into the tip-base metal distance calculation circuit 14, and the sum of the wire protrusion length and the arc length is calculated by the tip-base metal distance calculation circuit 14. And output it. Next, the chip / base metal distance calculation circuit 14
The proper distance between the chips and the base metal set by the distance between the base metal and the distance between the base metal and the base metal according to the welding condition is input into the deviation calculation circuit 15, and the difference calculation circuit 15 uses the difference calculation circuit 15 The deviation of the distance is calculated and output. This deviation value is the amount of deviation from the appropriate tip-base metal distance, but from welding experiments, there is no welding defect, no welding of the tip and wire, and there is no noticeable change in the weld bead shape. The range of is about ± of the appropriate tip-base metal distance.
Since it was found to be (7-8)%, the following constitution was taken as a technical means for notifying the welding operator of the necessity of correcting the welding torch height.

The comparator circuit 17 shown in FIG. 1 receives the deviation value obtained by the above calculation as one input, and the range of the deviation value with respect to the appropriate distance between the proper chip and the base material is called a dead zone. The dead zone set value set in step 2 is used as the other input, and the relationship between the chip-base material distance deviation and the comparison circuit output is as shown in FIG. That is, the comparison circuit output is 0 when the distance deviation between the tip and the base material is within the range of the dead zone set value, and the comparison circuit output is 0 when the distance deviation between the tip and the base material is positive and exceeds the range of the dead zone set value. A positive signal is output as the circuit output, and a negative signal is output as the comparison circuit output when the distance deviation between the tip and the base material is negative and exceeds the dead zone setting value range. The display device 19 provides a display that can be visually or audibly discriminated by the welding operator according to the three states of the output of the comparison circuit.

As a concrete example of the display device 19, (1) depending on the output level of the comparison circuit 17, when the distance between the chip and the base material is large (the deviation is positive and exceeds the dead zone setting value range). No sound when the distance between the tip and the base metal is appropriate (the deviation is within the dead zone setting value), and when the distance between the tip and the base material is small (the deviation is negative and exceeds the dead zone setting value) A sound display device in which the pitch changes in three steps of low tone, (2) A sound display device which emits two kinds of sounds of "large" and "small" when the distance between the chip and the base material is large and small. (3) Two-color lamp display device with red lamp lighting when the distance between the chip and the base material is large, and green lamp lighting when the distance between the chip and the base material is large. (4) + (plus) sign when the distance between the chip and the base material is large, appropriate Is 0 (zero) sign, and is smaller than-(my Scan) Preparative liquid crystal display device for displaying the 3 code of the code and the like.

By installing these display devices 19 on the front panel of the welding current / voltage controller 7 or the welding power source 6 at the hand of the welding operator, the welding operator can set the tip according to the contents displayed on the display device 19. -The welding torch height can be corrected by oneself so that the distance between the base materials is kept within an appropriate range.

In the above-mentioned embodiment, an example in which individual calculation circuits and comparison circuits are used as the wire protrusion length and arc length calculation means, the tip-base metal distance calculation means, the deviation calculation means and the comparison means has been described. These series of functions can also be realized by the program processing of.

[0030]

As described above, according to the present invention, the welding operator can determine the suitability of the distance between the tip and the base metal during welding by means of the display on the display device. It can be easily corrected to keep the distance between the tip and the base metal to an appropriate value according to the welding conditions. As a result, even beginners can perform stable semi-automatic arc welding at an appropriate torch height as well as a skilled worker.Therefore, the welding operation is interrupted due to welding of the tip and wire during welding, and the torch height is excessive. It is possible to avoid the occurrence of welding defects due to poor gas shielding caused by the above, and to improve the welding quality and reliability and to improve the welding work efficiency.

Further, by adding a constant arc length control function to the semi-automatic arc welding machine of the present invention, it becomes possible to perform welding at a constant arc length in addition to optimizing the distance between the tip and the base metal, and thus a welding torch. It is possible to make the penetration depth and the weld bead width uniform by moving at a constant speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a partially enlarged view of a welding arc portion of FIG.

FIG. 3 is a diagram showing a relationship between a chip / base material distance deviation and a comparison circuit output.

[Explanation of symbols]

1 ... Welding torch, 2 ... Tip, 3 ... Base metal, 4 ... Arc,
5 ... Wire, 6 ... Welding power source, 7 ... Welding current / voltage controller, 8 ... Wire feeding motor, 9 ... Wire feeding roller, 1
0 ... Wire feeding speed detector, 11 ... Welding current detector, 1
2 ... Chip-base metal voltage detector, 13 ... Wire protrusion length and arc length calculation circuit, 14 ... Chip-base material distance calculation circuit, 15 ... Deviation calculation circuit, 16 ... Chip-base material distance setter, 17 ... Comparison circuit, 18 ... Dead band setting device, 19 ...
Display device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takayuki Kashima             2100 Kamiimazumi, Ebina City, Kanagawa Prefecture             Within Kou Co., Ltd. (72) Inventor Tsuneo Mita             2100 Kamiimazumi, Ebina City, Kanagawa Prefecture             Within Kou Co., Ltd.

Claims (2)

[Claims] 1. A welding torch that is manually operated by a welder, a wire feeding device that feeds a wire while contacting the inner surface of the tip of the welding torch, and a welding power source that supplies electric power to the tip and the base metal. In a semi-automatic arc welder equipped with, a calculating means for calculating the wire protrusion length and the arc length from the respective detection values of the welding current detector, the tip-base metal voltage detector, and the wire feeding speed detector, and the above-mentioned calculation The wire-projection length and arc length obtained in step 2 are input, and the sum of the two is output as the tip-base metal distance calculation means, and the output of this tip-base metal distance calculation means and welding conditions Input the chip-base metal distance set by the chip-base metal distance setter according to the above, and output the deviation calculation means that outputs the deviation of the chip-base metal distance between the two. Input When the input value of exceeds the predetermined deviation range, the comparison means that outputs an operation signal and the operation signal from this comparison means operate to check that the distance between the tip and the base metal during welding exceeds the appropriate range. A semi-automatic arc welder characterized by having a display device for notifying the welding operator. 2. The comparing means discriminates whether the deviation between the tip and the base material is positive or negative, and the display device indicates that the deviation is positive and exceeds a predetermined deviation range, and that the deviation is negative and exceeds the predetermined deviation range. The semi-automatic arc welder according to claim 1, wherein the semi-automatic arc welder is displayed separately from the case.