JPH02218543A - Grinding method for mig weld zone - Google Patents

Abstract

PURPOSE:To obtain a finishing face of high accuracy by dividing a MIG weld zone along the weld line direction and executing a grind processing once again according to the quality of the finishing detected on each section while executing the grind processing for the whole weld line. CONSTITUTION:A sander 8 for grinding is provided at the arm 6 tip of a robot 4 and a face like sensor 9 detecting the quality of a grinding finish face is provided at the rear part in the work direction of the sander 8. The arm 6 of the robot 4 is controlled by being operated by the controller dividing a welding bead 3 at the interval in the grinding direction. The controller measures the state of the grinding finish face of just after grinding by the face like sensor 9 on each area divided uniformly in advance, deciding the surface accuracy of the grind finishing face by the presence of a rise section and in case of any rise being found, re-grinding is executed by the sander 8 as an NG area and in case of no rise the grinding of the following area is transferred to as an OK area, and the grind finishing is completed by repeating this.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a MIG weld part grinding method for grinding and finishing a weld bead part by MIG welding.

(Prior art) As a conventional method for grinding a welded part of this type, Japanese Patent Application Laid-Open No. 62-2
As seen in Publication No. 46465, the shape of the raised weld bead is recognized in advance by a surface shape sensor, an ideal finished surface with no unevenness is extracted, the bead center position, bead height, and bead width are calculated and stored. By correcting the difference between the previously taught bead position or the current position of the grinding wheel by the first linear step motor and the memorized bead center position, that is, the amount of deviation, the grinding wheel can be moved to the bead center position at any time. Using the method of bending and the memorized bead height, find the amount to be polished from the bead height position - ideal finished surface, and while keeping the pressure with which the polishing tool is pressing the workpiece within a constant pressure range, There are two methods: one method involves gradually pressing the polishing tool against the workpiece to achieve an ideal finished surface with no unevenness, and the other method involves polishing the weld bead.

(Problem to be solved by the invention) However, the above proposal is related to grinding technology and does not evaluate the finished surface after grinding, so there is no guarantee that the ground surface is actually sufficiently finished. It was something. When such a ground surface is painted in a subsequent process, weld beads that are not sufficiently finished may clearly appear, which may reduce the product value.

The present invention was devised to solve these problems, and an object of the present invention is to provide a novel MIG weld grinding method that can obtain a highly accurate finished surface.

(Means and Effects for Solving the Problems) When grinding a MIG weld, the present invention divides the MIG weld along the weld line direction, and performs grinding for each weld while performing the grinding process on all the weld lines. For each section, the grinding finish state of the section is detected by a sensor, and depending on the quality of the finish, the grinding process is executed again for each section to evaluate whether the ground surface is sufficiently finished. The grinding process is then executed.

(Example) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

First, an automatic MIG weld finishing device employed in the present invention will be explained.

FIG. 1 shows part of a vehicle manufacturing line.

As shown in the figure, a trolley 2 carrying an automobile body 1 as a workpiece is moved on the line. This car body 1
As shown in Fig. 2, weld bead part 3 by MIG welding
have.

On the other hand, a robot 4 constituting an automatic MIG welding part finishing device is installed in the middle of the line, and with the trolley 2 temporarily stopped at this position, the robot 4 cuts the weld bead 3 of the automobile body 1. It is ready to be ground and finished.

That is, a sump 8 for grinding is provided at the tip of the arm 6 of this robot 4, and behind this sump 8 in the working direction, as shown in FIG. A surface shape sensor 9 is provided.

In this finishing apparatus, a sump 8, a surface shape sensor 9, and a robot 4 are each controlled by a microcomputer.

The arm 6 of the robot 4 is controlled by a controller (not shown) that divides the weld bead portion 3 at intervals in the grinding direction. The drive of the sump 8 that performs grinding is also controlled.

The dividing controller has a function of dividing the weld bead portion 3 into equal intervals along its longitudinal direction (Fig. 3), or in the process of grinding the weld bead portion 3.
It has a function (FIG. 6) that distinguishes between an insufficiently ground finished part (NG) and a sufficiently ground finished part that meets the target (OK) and classifies them based on the discrimination.

In any of the divided areas, the operation of the sump 8 is controlled so that the sump 8 performs the grinding again for the grinding finished part (NG) where the grinding is insufficient.

The surface shape sensor 9 detects the state of the finished surface of the weld bead portion 3 immediately after being ground by the sump 8. In this case, the surface shape sensor 9 is attached to the rear of the powder 8 in the direction of the grinding operation (see FIG. 2).

The robot 4 is configured to have its arm 6 tilted and extended, its wrist tilted and rotated, and its support column rotated, etc., controlled by a controller.

In addition, the first function of the controller is to measure the condition of the ground surface immediately after grinding using the surface shape sensor 9 in each area that has been equally divided in advance during the grinding process, and to calculate the degree of area of the ground surface by measuring the area of the ground surface immediately after grinding. Judgment is made based on the presence or absence of the area, and if there is a bulge, it is determined to be an NG area and the area is re-ground with the sump 8. If there is no bulge, it is determined to be an OK area and the grinding proceeds to the next area, and this process is repeated to complete the grinding finish.

In addition, as a second function, the controller uses a sensor 9 to detect the state of the ground surface immediately after grinding in the process of grinding work, and determines the starting point and end point of insufficient grinding. By dividing the area, a regrinding area and a regrinding unnecessary area are set, and the regrinding area is treated as an NG area and is reground by the sump 8, and the regrinding unnecessary area is treated as an OK area and the grinding finish is completed.

Next, the grinding method of the present invention will be explained.

Basically, when grinding the weld bead part 3 which is a MIG weld part, the present invention divides the weld bead part 3 along the weld line direction, and performs the grinding process on the entire weld line while each division Each time, the grinding finish state of the relevant section is detected by a sensor 9, and the grinding process is executed again for each section depending on the quality of the finish.

As shown in FIG. 3, while grinding the entire subdivided area, OK area 1. TV, V, Vl, IXtN
G areas n, m, ■, ■ are detected, and then, as shown in Fig. 4, the OK areas ■, ■, are ground while passing through the entire NG area.
Finally, as shown in FIG. 5, the entire NG area is ground through, and the grinding is completed as OK areas (■, ■) are detected.

In this case, if an NG area is detected during the grinding operation, the area currently being ground may be immediately returned to the N0 area and finished while being re-ground one by one.

Furthermore, as shown in FIG. 6, in the process of grinding the entire length of the weld bead 3, the starting point of any insufficiently ground area is detected at position A immediately after grinding, and the current area Detects the end point at position B and sets an NG area.Similarly, an NG area is also set between positions C and D, other areas are considered OK areas, and then NG areas are set. Ward area-
By re-grinding B and CD, the N0 area is sequentially narrowed and the OK area is enlarged to make the entire area OK.

(Effects of the Invention) As described above, the present invention exhibits the following excellent effects.

When grinding a MIG weld, the MIG weld is divided along the direction of the weld line, and while grinding is performed on all weld lines, a sensor detects the grinding finish state of each section. Since the grinding process is executed again for each section depending on the quality of the finish, it is possible to execute the grinding process while evaluating whether or not the ground surface is sufficiently finished. Since the treatment can be carried out only on the necessary parts, a good finished surface can be efficiently ensured.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the automatic MIG welding part finishing device adopted in the present invention, Fig. 2 is a schematic diagram showing the working status of the main parts, and Figs. 3 to 5 show areas equally divided. FIG. 6 is an explanatory diagram of a finishing method based on arbitrarily divided areas. Figure 1

Claims (1)

[Claims] When grinding a MIG weld, the MIG weld is divided along the direction of the weld line, and while grinding is performed on all the weld lines, the grinding finish state of each of the above sections is measured using a sensor. A method for grinding a MIG welded part, characterized in that the grinding process is performed again for each section depending on the quality of the finish.