JPH03248775A - Method and instrument for testing wire feeding condition into welding machine - Google Patents

Abstract

PURPOSE:To find out bad condition in wire feeding system at early time by measuring a wire feeding force from welding torch tip in a welding wire inchiugly fed and deciding the wire feeding condition. CONSTITUTION:The welding wire 6 is inchiugly fed and the feeding force of welding wire 6 pushed out from the tip part 4 of welding torch 1 is measured and whether the wire feeding condition is good or bad, is decided from this measured result. By this method, in the automatic welder of welding robot, etc., consumption of liner tip, etc., or bad condition in the wire feeding system is found out at early time and the generation of bed welding is prevented and also exchanging time of consumable parts can be predicted without depending on arc strike.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an arc welding machine that uses a wire as a consumable electrode. Concerning test method and device.

[Conventional technology]

The conventional method for testing wire feedability is to perform inching feed for a certain period of time, measure the length of the wire extruded from the tip of the welding torch, and determine whether the wire feedability is good or bad by looking at the variation. there were.

However, since the method of measuring the length of the extruded wire cannot be automated and testing is time-consuming, it has not been adopted in automatic welding machines such as welding robots. Furthermore, there was no test method that could easily determine whether the cause of poor feeding was in the welding torch, wire feeding device, or wire feeding control device.

[Problem to be solved by the invention]

Since the quality of wire feedability directly affects the welding result, there is a long-awaited need for a simple wire feedability test method and testing device that can be applied to automatic welding machines in order to prevent welding defects.

An object of the present invention is to solve this problem.

[Means to solve the problem]

The wire feedability test method of the present invention involves inching a welding wire, measuring the feeding force of the welding wire pushed out from the tip of a welding torch, and determining whether the wire feedability is good or bad based on the measurement results. be.

Further, the wire feedability test device of the present invention includes a torch positioning jig that receives the tip of the welding torch, and a welding wire that is pushed out from the tip of the welding torch while the welding torch is positioned by the torch positioning jig. It has a pressure receiving plate set in a predetermined relationship position with respect to the torch positioning jig so that the tip of the tip touches it, and a force measuring device that converts and measures the wire feeding force at the tip exit into an electrical signal. There is.

[Function] The basic function of a welding torch that uses a wire as a consumable electrode is as shown in FIG. It is guided to the arc generation position by a similar wire guide, and power is supplied by the tip 4 at the tip (the power supply path is not shown). In such a welding torch, if the wire feeding force at the torch inlet is F, a part of the feeding force F is consumed as energy that causes frictional heat between the liner 3 and tip 4 and mechanical strain in the wire, etc. Therefore, the wire feeding force f at the exit of the tip 4 becomes smaller than F. Therefore, even if F and the wire diameter are constant, f changes depending on mechanical conditions such as the inner diameter and material of the liner 3 and tip 4, which are the wire feeding path, as well as the surface condition. Furthermore, if the wire feeding force F at the torch inlet changes due to slipping of the feeding roller of the wire feeding device, energy loss in the wire feeding path from the wire feeding device to the torch inlet, etc., the wire feeding force F at the torch inlet changes accordingly. The wire feeding force f also changes. If f becomes too small, not only will the wire not come out smoothly, but the wire will become a chip due to sparks during power supply. If you don't put it on, a problem will occur. For this reason, in the wire feedability test method of the present invention, the tip of the welding wire pushed out from the tip by inching feed is brought into contact with the pressure receiving plate of the force measuring device, so that the wire feeding force f at the tip exit can be measured electrically. This method converts it into a signal and measures it, and then judges whether the wire feedability is good or bad based on the measurement results. By automating the measurement of the wire feeding force f, it can be easily applied to automatic welding machines such as welding robots. can.

During measurement, the wire may bend between the tip outlet and the pressure receiving plate, so it is desirable that the distance therebetween be as small and constant as possible. Therefore, in the wire feedability testing device of the present invention, a torch positioning jig is provided to receive the tip of the welding torch during measurement, and a pressure receiving plate is installed at a predetermined position relative to this torch positioning jig. This prevents the wire from bending between the chip outlet and the pressure plate.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 4 shows an example of a welding torch used in an automatic welding machine. In FIG. 4, 1 is a welding torch, and a tip 4 and a nozzle 5 are attached to the tip of a torch body 2 which has a built-in liner 3 and a power supply conductor shown in FIG. 5, and a welding wire 6 is pushed out from the tip 4. , shielding gas is emitted from the nozzle 5. This welding torch is used by being fixed to a torch support 7 such as a robot arm with a clamper 8, and by connecting the torch inlet to a wire feeding device (not shown).

FIG. 1 and FIG. 2 show the state during a test using the wire feedability testing device of the present invention. 1 and 2, 9 is a torch positioning jig, which is provided with a through hole 9a having a diameter smaller than the inner diameter of the tip of the nozzle 5 of the welding torch 1 and larger than the outer diameter of the tip of the tip 4. ing. Force measuring device 10
One end of the pressure receiving plate 11 is fixed to the torch positioning jig 9 so as to face the rear end of the through hole 9a. Strain gauge 12 mounted on pressure receiving plate 11 as a mechanical-electric conversion element
is connected to the bridge 14 of the measurement circuit 13, and the bridge 1
The output terminal of 4 is connected to an output converter 16 via an amplifier 15. The torch positioning jig 9 and the pressure receiving plate 11 are installed as one set at a specific position within the movement range of the welding torch.

As a test method, as shown in Fig. 1, welding torch 1
Place the tip of the nozzle 5 on the front of the torch positioning jig 9, and position the torch so that the tip of the tip 4 enters the through hole 9a. In order to reduce the amount of noise and weld in narrow spaces, the tip of the tip should be placed 1 inch lower than the tip of the nozzle.
(2InX11 protrusion in many cases), by this positioning, the distance l between the chip 4 and the pressure receiving plate 11 can be made as small as possible and constant.

In this state, when the welding wire 6 is inched fed and the tip of the welding wire 6 pushed out from the tip 4 butts against the pressure receiving plate 11, the deflection generated in the pressure receiving plate 11 due to the wire feeding force at the tip exit causes distortion. It is detected by the gauge 12, and the output of the bridge 14 changes. This output change is then amplified by an amplifier 15 and sent to an output converter 16. The output converter 16 converts the sent electrical signal into a wire feeding force at the tip exit for recording or display.

Here, when the force F shown in FIG. 3 is applied as the wire feeding force at the torch entrance, the wire feeding force f at the tip exit is measured as the output a or b shown in FIG. 3. That is, when the energy loss in the wire feeding path is small, the output is large and the output rises quickly as shown in Figure 3a, but when the energy loss in the wire feeding path is large, the output is large as shown in Figure 3a. Since the output is small and the rise of the output is slow as shown in b, it is possible to judge whether the feedability is good or bad from the measurement results of the outputs a and b.

The quality of the feedability may be determined based on the magnitude of the output after rising, or may be determined based on the rising slope of the output during a constant measurement time t (for example, 0.1 seconds). Furthermore, in order to prevent deformation and buckling of the wire due to slipping of the feeding roller, the tendency shown in FIG. 3 does not change even if the feeding speed is slowed down.

In automatic welding machines such as welding robots, by performing this feedability test for each welding process, it is possible to prevent welding defects due to defects in the wire feeding system. In addition, by using the same welding torch and sequentially changing the wire feeding device and wire feeding control device and conducting a test, it is possible to determine the quality of each part.

As the mechanical-electric conversion element of the force measuring device, an element (piezoelectric element, differential transformer, etc.) that detects strain or displacement other than a strain gauge can also be used.

Furthermore, it goes without saying that the welding torch 1 may be positioned relative to the through hole 9a based on the outer diameter of the nozzle 5.

〔Effect of the invention〕

According to the present invention, it is possible to easily judge whether the wire feeding performance is good or bad based on the measurement result of the wire feeding force at the tip exit, so that it is possible to easily judge whether the wire feeding performance is good or bad based on the measurement result of the wire feeding force at the tip exit. It is possible to quickly recognize problems in the supply system and prevent welding defects from occurring, and it is also possible to know when to replace consumable parts without generating arcs, making maintenance easier.

Furthermore, since it is possible to determine the quality of the component parts of the wire feeding system such as the welding torch, wire feeding device, wire feeding control device, etc., it is possible to provide a welding device with better feeding performance based on the judgment results. I can do it.

[Brief explanation of drawings]

Fig. 1 is a partially cross-sectional configuration diagram showing the test state of the wire feedability testing device according to the present invention, Fig. 2 is a view taken in the direction of arrow A in Fig. 1, and Fig. 3 shows the wire feeding force at the torch inlet. A waveform diagram showing the relationship between F and the wire feeding force f at the tip exit, Fig. 4 is a cut side view showing an example of a welding torch used in an automatic welding machine, and Fig. 5 is a diagram showing the welding torch shown in Fig. 4. FIG. 3 is an explanatory diagram of basic functions. DESCRIPTION OF SYMBOLS 1... Welding torch, 4... Chip, 6-... Welding wire, 9... Torch positioning jig, 1o... Force measuring device, 11... Pressure receiving plate, 12... Strain gauge , 13...
-Measuring circuit, 16...output converter. Figure + -1-; No. 11 Torch 4--- +-, 7゜5-11 No. 1 and 6--- @Kyo [Y V 9-m-Torch 4 Stand 1 [j 111o --- Force surplus sushi II --- First FL failure 12 --- First tension case 13 ---; Judgment - n% Fig. 1 Fig.

Claims (1)

[Claims] 1. Wire feed of a welding machine that inching feeds a welding wire, measures the feeding force of the welding wire pushed out from the tip of a welding torch, and determines whether the wire feedability is good or bad based on the measurement result. Feeding test method. 2. A torch positioning jig that receives the tip of the welding torch, and with the welding torch positioned by this torch positioning jig, the torch positioning jig is placed in such a way that the tip of the welding wire pushed out from the tip of the welding torch hits the torch positioning jig. On the other hand, a wire feedability testing device for a welding machine is comprised of a pressure receiving plate installed at a predetermined relative position and a force measuring device that converts the wire feeding force at the tip outlet into an electrical signal and measures it.