JPS643637Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a grinding device that automatically deburrs, for example, a casting.

<Conventional technology> When producing cast iron products, it is necessary to remove the thin fin-like cast burrs that are formed when hot water flows into the joints of the molds, as well as the bulges that are inevitably formed due to gas venting in the molds. is necessary. When mass-producing the same type of cast metal products, deburring has traditionally been performed by automatic grinding using a robot in order to improve work efficiency. In other words, the grinding tool is installed on a robot arm of the so-called teaching playback type, which automatically repeats the procedure once operated by the operator, and the grinding tool moves to follow the burr of the cast product by operating the robot arm. This burr is removed by grinding. However, due to the nature of casting, there is a limit to product accuracy, and dimensional errors occur between cast products, so no matter how high-precision positioning equipment is used to position and hold the workpiece, casting products,
Errors in burr position occur between individual products. For this reason, when grinding using the teaching playback method described above, errors may occur between the movement path of the grinding tool based on teaching and the actual burr position, resulting in reduced work efficiency due to product defects and rework. had occurred.

Therefore, in order to deal with the above-mentioned problems, measures as shown in FIGS. 4 to 6 have conventionally been taken. This means irradiates a burr 2 protruding from a cast product 1 with light from a light source 3 diagonally above,
It uses the principle that the boundary between the dark area caused by the shadow on one side of the burr 2 and the bright area on the other side of the burr 2, that is, the position of the burr 2, is detected by the upper image sensor 4, and the light source 3 and the image sensor 4 is attached to a teaching playback type robot arm (not shown) together with a grinding tool 5, and before grinding, the robot arm is operated based on the taught data to generate the actual burr 2 detected by the image sensor 4. After correcting the deviation between the position of the robot arm and the data taught to the robot arm, the robot arm is operated again based on the corrected data and the burr 2 is ground away by the grinding tool 5.

<Problems to be solved by the invention> The above-mentioned countermeasures can improve the positional accuracy of grinding, but the robot arm must be operated to correct data for each workpiece before grinding. Therefore, there was a problem in that the working time was increased by that amount, resulting in a significant drop in working efficiency.

The present invention was devised in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide an automatic grinding device that realizes highly accurate and efficient grinding work.

<Means and effects for solving the problems> The automatic grinding device according to the present invention is equipped with an image sensor along with a grinding tool on a robot arm, and detects the boundary between bright and dark caused by sparks during grinding by the grinding tool within the field of view of the image sensor. A robot arm that detects the position and controls the robot arm so that this boundary position matches the boundary position that should occur within the field of view when the grinding tool is grinding while following approximately the center line of the part to be ground. The grinding work is performed while correcting the data taught to the robot arm in advance.
Realizes highly accurate and highly efficient grinding of the part to be ground of the workpiece.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. Figure 1 is a side view of the automatic grinding device of this embodiment, Figures 2a and b are front and side views of the tip of the robot arm, respectively, and Figure 3 is an explanation of the operation of the grinding tool viewed from above. It is a diagram.

As shown in the figure, the automatic grinding device is constructed by providing a grinding tool 11 and an image sensor 12 at the tip of a teaching playback type multi-joint robot arm 10, and the grinding tool 11 and the image sensor 12 are connected to lead wires, respectively. It is connected to the control device 10a of the robot arm 10 via 13 and 14.

The image sensor 12 is attached to the upper front surface of the grinding tool 11 and is directed toward the tip of the grinding wheel 11a provided in the grinding tool 11, and faces the burr 16 during the grinding operation. Therefore, casting product 1
When the burr 16 of No. 5 is ground with the tip of the grindstone 11a, sparks 17 scattered in the direction of rotation of the grindstone 11a enter the field of view 12a of the image sensor 12. The field of view 12a is a collection of a large number of pixels, and the image sensor 12 detects the generation state of the spark 17 as a boundary position between brightness and darkness within the field of view 12a due to the spark 17. The control device 10a connected to the image sensor 12 includes a grindstone 11.
Field of view 1 shows how sparks are generated when grinding is performed with the tip of the burr 16 located approximately on the center line of the burr 16.
2a, and controls the operation of the robot arm 10 based on teaching so that the spark generation state actually detected by the image sensor 12 matches this spark generation state. do. For example, if the state in which ideal grinding is performed as described above is set in advance as a state in which the boundary between brightness and darkness caused by the sparks 17 is in the center of the field of view 12a, the actual sparks 17 detected by the image sensor 12 The robot arm 10 is controlled to adjust the grinding position by the grinding tool 11 so that the boundary between bright and dark is located at the center of the field of view 12a.

Therefore, the robot arm 10 operates based on the data taught in advance and grinds the grinding tool 1.
1, when the burr 16 is followed and removed by grinding, according to the above configuration, the spark 17 during actual grinding
The operation of the robot arm 10 is corrected and controlled based on the occurrence state of the burr 16, so that the grinding tool 11 is maintained in a state where it can accurately catch and grind the burr 16. Therefore, even if an error occurs between the actual position of the burr 16 and the teaching to the robot arm 10, the grinding tool 11 always follows the burr 16 and a good grinding operation is automatically performed.

In the above embodiment, the present invention was applied to deburring a cast product, but the present invention is of course not limited to this and can be applied to grinding work of various parts to be ground. Further, an image sensor capable of two-dimensional detection may be used, and in this way, the contact state of the grindstone and the burr can also be controlled based on the component of the spark in the direction in which the burr protrudes.

<Effect of invention> According to the present invention, the following effects can be obtained.

Even if there is some error in teaching the grinding trajectory to the robot arm from the actual position of the part to be ground, it will be automatically corrected during grinding.
Teaching work can be simplified.

Since the teaching data of the robot arm is automatically corrected for dimensional errors between workpieces during grinding work, there is no need to correct the teaching data, which reduces grinding work efficiency.
Grinding work can be performed with high precision.

Even if there is an error in the positioning accuracy of the workpiece, the grinding tool always follows the part to be ground, so the workpiece positioning device can be made simple and inexpensive.

Compared to conventional correction means using shadows (see Figures 4 to 6), a light source is not required, so the tip of the robot arm does not need to be made too large, and the device can cover parts of the workpiece other than the part to be ground. It is possible to reduce the dead space where grinding becomes impossible due to interference.

[Brief explanation of drawings]

1 to 3 relate to an embodiment of the present invention, in which FIG. 1 is a side view of an automatic grinding device, FIGS. 2a and 2b are a front view and a side view of the tip of a robot arm, respectively.
Figure 3 is an explanatory diagram of the operation of the grinding tool viewed from above, Figures 4 to 6 relate to conventional correction means, Figure 4 is a principle diagram of the means, and Figure 5 shows the shadows caused by burrs. The conceptual diagram shown in FIGS. 6a and 6b is a front view and a side view of the tip of the robot arm, respectively. In the drawing, 10 is a robot arm, 10a is a control device, 11 is a grinding tool, 12 is an image sensor,
12a is a field of view, 15 is a cast product, 16 is a burr, 1
7 is a spark.

Claims (1)

[Scope of utility model registration request] In an automatic grinding device, a grinding tool is provided at the tip of a robot arm, and the grinding tool follows a part to be ground of a workpiece by the operation of the robot arm. and an image sensor that detects a boundary position between brightness and darkness that occurs within a field of view due to sparks during grinding, and a boundary between brightness and darkness that should occur within the field of view when the grinding tool is grinding approximately on the center line of the part to be ground. An automatic grinding device comprising: a control device into which a position is input in advance and which controls the robot arm so that a boundary position detected by the image sensor coincides with the boundary position.