JPH0352773A - Hot wire heater - Google Patents

Abstract

PURPOSE:To easily realize a desired molten state by providing means for setting a wire heating current and wire feed speed, controlling the respective outputs and calculating the ratio of the square of the wire heating current and the wire feed speed. CONSTITUTION:Setters 7, 8 which can respectively independently set the wire heating current and the wire feed speed, respective control means 5, 3 and the arithmetic means 6 for calculating the ratio of the square of the wire heating current and the wire feed speed are provided. The proportional constant (k) to attain (wire feed speed)=k.(wire heating current)<2> is calculated at the time of the start of computation and the wire heating current is so controlled that the above-mentioned equation holds automatically with a change in the wire feed speed during welding. Since the current is detected as a voltage signal by a shunt or Hall element, etc., the measurement of the current is not affected by the length of a power feed cable. The control is not affected at all by wirings, etc., if not a method of detecting the current, etc., and feeding back the same but a feed forward control to support a variable is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a welding device, and more particularly to a hot wire heating device suitable for controlling hot wire welding in which filler wire is heated with electricity.

[Conventional technology]

In hot wire welding, it is important to keep the filler wire feeding speed and wire heating current appropriate. Fourth
The figure schematically shows the configuration of a wire heating device for conventional hot wire welding. In the figure, 1 is a hot wire heating device, 2 is a heating power source, 4 is a wire feeder, 9 is a wire, 10 is a base material, 11 is a TIG welding machine, 12 is a TIG
}-ch, 13 is a current/voltage measuring circuit, and 14 is a control circuit.

For wire heating control, a function is experimentally determined using the filler wire feeding speed and the voltage between the filler wire base material as variables, and an appropriate wire current is obtained. This method of hot wire welding equipment is
9 There is No. 4. However, since the voltage between the filler wire and the base material is used as a variable, the experimental formula determined in advance will not fit unless the protruding length of the wire is kept constant.

In addition, the hot wire welding device disclosed in Japanese Patent Application Laid-Open No. 60-822278 detects the power applied to the wire from the wire voltage and wire current, and uses the filler applied power and filler wire feeding speed as variables to weld the wire. Appropriate heating control is performed.

Both methods require wiring to measure the voltage between the filler wires, but if the voltage measurement point is placed near the wire heating power source, the voltage generated by the cable leading to the power supply to the wires will also be added. Therefore, a voltage higher than the actual wire voltage will be detected. If the detection cable is routed near the power supply point, the effect of voltage drop along the way will be eliminated, but the work will still be troublesome.

[Problem to be solved by the invention]

The above conventional technology uses the voltage between the wire base materials as one of the variables as a feedback means for wire heating control. However, since the voltage signal varies greatly depending on the measurement position, there is a problem in that the control constant varies depending on the length of the wire energizing cable.

An object of the present invention is to provide a hot wire heating device that controls the heating current of the wire regardless of the length of the cable.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention is directed to a hot wire heating device equipped with a heating power source for heating a fryer for TIG welding and a fryer feeding mechanism.

A setting device that can independently set the wire heating current and the wire feeding speed, a control means that controls the output of each, and an arithmetic means that calculates the ratio of the square of the wire heating current and the wire feeding speed are provided. , at the start of welding, calculate the proportionality constant k, where (wire feeding speed) = k (wire heating current) The device is characterized in that it is configured to control the current.

[Effect]

Current measurement is not affected by the length of the power supply cable because it is detected as a voltage signal using a shunt or a Hall element. Also, if you perform feedforward control that supports variables, rather than detecting and feeding back control variables such as current, there will be no influence from wiring or the like.

[Embodiments of the invention]

FIG. 1 schematically shows an example of a combination of the hot wire heating device of the present invention and TIG welding.

The hot wire heating device I includes a heating power source 2, a current control circuit 3, a wire feeder 4, a feeding control circuit 5, an arithmetic circuit 6,
It is composed of a wire current setting device 7 and a wire feeding speed setting device 8.

In the figure, 9 is a wire, 1O is a base material, 1] is a TIG welding machine, and 12 is a TIGI.

The welding operator can arbitrarily set the wire feeding speed V' and the wire current 1w using the respective setting devices 7.8. That is, the operator himself/herself sets the variables for wire heating control. Heat generation amount Q of wire and current I
There is a "QOOI" relationship between them as shown in Figure 2, so at the start of welding, the arithmetic circuit 6 in Figure 1 establishes Vf=k-1w2 for the set Iw and Vf. Calculate and store the constant k.

During welding, the wire feeding speed changes from Vf to Vf based on this constant k.
', Iw is changed to lw' so that Vf' = k Iw'2.

Further, when the wire current 1w is changed to 1w" during welding, the constant k is changed to k" so that Vf=k"Iw".

Through such control, it is possible to stably obtain the heating and melting state desired by the operator.

FIG. 3 is a diagram showing a flowchart of a heating control method for the hot wire heating device of the present invention.

When welding is started, a proportionality constant k is determined based on the wire current 1w and the wire feeding speed vr set by the wire current setting device 7 and the wire feeding speed setting device 8 in FIG. is calculated, and control is started during welding.During welding, if there is no request to change the wire current or feeding speed, control will continue with the set values, but if a change is requested from the hand control box, etc. Sometimes the following control is performed.

When there is a request to change the wire feeding speed Vf, for example, V
When f is changed to Vf, Iw is changed to Iw, so that Vf,=klw,'',
Keep the molten state of the wire constant. Further, when there is a request to change the wire current 1w during welding, the proportionality constant k is changed so as to change the molten state of the wire itself. For example, if Iw is changed to IW2, Vf=k21w
2'' is newly calculated, and the wire heating control is thereafter performed using this k2.

The above-described control is repeated until the welding is completed, and the heating state of the wire is always maintained at the state desired by the welding operator.

The present invention maintains wire heating control constant when there is a request to change the wire feed speed or wire current during welding, but it also applies to welding where the wire feed speed changes automatically. It is valid.

For example, in all-position welding of fixed pipes, in most cases welding is performed while gradually changing the wire feeding speed depending on the position. By controlling the wire current in response to changes in the wire feeding speed as described above, stable welding can always be performed.

〔Effect of the invention〕

According to the present invention, there is no need to determine the relationship between the wire feeding speed and the wire voltage or wire current through experiments in advance.
Further, since there is no need to detect the wire voltage, the wire melting state desired by the operator can be easily achieved.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the overall structure of a hot wire heating device according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing the relationship between wire heating current and wire heat generation, and FIG. 3 is a diagram showing the relationship between wire heating current and wire heat generation. FIG. 4 is a flowchart of wire heating control of the wire heating device according to the embodiment, and FIG. 4 is a diagram schematically showing the configuration of a conventional hot wire heating device. 1... Hot wire heating device, 2... Heating power source, 3
...Current control circuit, 4...Wire feeder, 5...
・Feeding control circuit, 6... Arithmetic circuit, 7... Wire current setting device, 8... Wire feeding speed setting device, 9... Wire ζ 1 0... Base material, ■ l. ...TIG welding machine, 12...TIG torch. Unexamined Japanese Patent Publication No. 3 52773 (4)

Claims (1)

[Claims] A heating power source that heats a filler wire for TIG welding;
A hot wire heating device equipped with a filler wire feeding mechanism includes a setting device that can independently set the wire heating current and wire feeding speed, a control means that controls the output of each, and a setting device that can independently set the wire heating current and wire feeding speed, and A calculation means for calculating the feed speed ratio is provided, and the wire feed speed is calculated at the start of welding.
=k・(wire heating current)^2 A proportional constant k is calculated, and the wire heating current is automatically controlled so that the above formula holds true when the wire feeding speed is changed during welding. Wire heating device.