JPS61240107A - Sensor unit - Google Patents

Abstract

PURPOSE:To enable rapid and accurate polishing finishing processing, by controlling a robot pivotally supporting a rubstone by simultaneously detecting the normal line stood on the free curved surface of a work, the undulation height remaining on the free curved surface and the roughness of the free curved surface. CONSTITUTION:The titled sensor unit is constituted of a sensor apparatus 10 for detecting the direction of the normal line stood on the free curved surface of a work 1 and the height of the undulation remaining on the curved surface 2 and a sensor apparatus 20 for detecting the surface roughness of the curved surface 2. The apparatus 10 is constituted of a plurality of sensor main bodies 3 formed by arranging probes 3A-3D on the same circumference, a power transmitting apparatus 4 for simultaneously applying rotary driving to said sensor main bodies 3 and a signal processor 12 equipped with an encoder 5 for calculating the direction of the normal line and the height of undulation. The apparatus 20 is constituted of a surface roughness meters 7 supported in a freely advancing and retracting state by hydraulic cylinders 6 so as to allow the detection parts for detecting the surface roughness of the work to face to the parts below the probes 3A-3D and the common rotary shaft 8 of the sensor bodies 3 are further arranged in parallel to the advancing and retracting stroke direction of the roughness meter 7.

Description

[Detailed Description of the Invention] Emperor and Duke of Industry! The present invention relates to a sensor unit, and more particularly to a polishing process for removing pick feed marks (cutting grooves) remaining on the surface of a press die after cutting the workpiece, for example, a press die. The present invention relates to a polishing preparation device that measures the normal direction, waviness, and surface roughness of the surface of a press mold during processing.

Workpieces with free-form curved surfaces, such as press molds used to form automobile fenders and doors, are rough-finished by cutting, and then a cutting tool such as a ball end mill is used to remove any defects on the surface of the workpiece. This manual polishing process, in which picked feed marks (cutting grooves) are removed using hand tools such as files, may result in dimensional accuracy and surface roughness depending on the skill of the operator. Since the process is highly influenced and takes a long time, it poses many obstacles to improving the quality of final products and reducing the cost of press molds.

In order to solve these problems, various methods of automating the polishing process have been studied in recent years.

(In such an automated method of polishing and finishing processes, in order to maintain the dimensional accuracy of the workpiece at a predetermined level and improve the productivity of the process, it is necessary to maintain a constant state of contact between the polishing whetstone and the workpiece. It is necessary to monitor and maintain optimal polishing finishing conditions.In order to improve the productivity of the polishing finishing process, it is desirable that the polishing wheel be placed in surface contact with the workpiece. As a means of imparting the function, as shown in FIG. 7(A), there is a method of imparting appropriate elasticity to the grindstone itself and creating a surface contact state by elastic deformation of the grindstone, or as shown in FIG. 7(B), A method is adopted in which the supporting posture of the grinding wheel is controlled so that the axis of the grinding wheel forms a line normal to the surface of the workpiece.
When polishing is performed while the grindstone is in point contact with the surface of the workpiece as shown in C), the polishing efficiency is significantly reduced due to the fact that the actual polishing area is restricted. However, in the polishing method that utilizes the elastic deformation of the grinding wheel as shown in Figure 7 (A), the pressure of the grinding wheel applied to the surface of the workpiece is affected by the unevenness of the elasticity of the grinding wheel. Therefore, the reproducibility of the surface shape of the workpiece decreases. On the other hand, with the method shown in Figure 7(B), although it is theoretically possible to keep the grinding wheel in constant surface contact with the workpiece, the axis of the grinding wheel is not accurately aligned with the surface of the workpiece. In practice, it is not easy to detect whether or not the object is pointing in the normal direction, and this point has been recognized as a practical difficulty.

Furthermore, when applying a mirror finish to the surface of a workpiece, it is necessary to use a surface roughness meter to measure the unevenness of the micron order that remains on the free-form surface of the workpiece. The needle is often used alone, which has the disadvantage of requiring a long time to measure surface roughness.

The main object of the present invention is to provide a device for measuring the normal direction of a workpiece surface, which is suitable for controlling the axial direction of a grindstone relative to the workpiece surface, which has been a problem in polishing and finishing workpieces having free-form surfaces. It's about doing.

Another main object of the present invention is to provide an apparatus for measuring waviness on a free-form surface and surface roughness, which is suitable for removing pickfeed marks (cutting grooves) remaining on the surface of a workpiece.

Another main object of the present invention is to provide a simultaneous measurement device that is capable of simultaneously measuring the normal direction and waviness of a workpiece surface and is suitable for improving measurement accuracy and shortening measurement time.

In view of this purpose of fortune-telling, the present invention detects the direction of the normal line erected on the free-form surface (2) of the workpiece (1) and the height of the undulations remaining on the free-form surface (2). First sensor device (10)
and a second sensor device (20) that detects the surface roughness of the free-form surface (2),
The first sensor device (10) includes a power transmission device (4) that simultaneously rotates a plurality of sensor bodies (3) each having its stylus arrayed on the same circumference; The second sensor device (20) constitutes the first sensor device. A surface roughness meter (supported so as to be movable back and forth by a fluid pressure cylinder device (6) so that the surface roughness detection area of the workpiece (1) is exposed below the stylus of the plurality of sensor bodies (3) 7), and furthermore, the common rotation axis (8) of the front and rear sensor bodies (3) is arranged parallel to the direction of the forward and backward stroke of the surface roughness needle (7). The unit is the gist.

- The workpiece (1) is detected by the first sensor device (10).
Detecting the height of the waviness remaining on the free-form surface (2) and the direction of the normal line to the free-form surface, and aligning the direction of the rotation axis of the grindstone with the direction of the normal line, When polishing the surface of the workpiece (1) or mirror finishing the surface of the workpiece (1), the first sensor device (
10), the second sensor device (20) integrally structured with the second sensor device (20) measures the micron-order unevenness remaining on the free-form surface of the workpiece (1), that is, the surface roughness.

FIG. 1 illustrates the overall structure of the first sensor device (10). It is a block diagram, and FIGS. 2 and 3 are a front view and a bottom view illustrating the detailed structure of the first sensor device (10). Further, FIG. 4 is a side view illustrating the overall structure of the second sensor device (20).

As seen in these drawings, the first sensor device (10
) consists of four sensor bodies (3), (3)--for example, a Magnescale and a low-pass filter ( 9), (9)-- and high-pass filter (11)
, (11)--, and an encoder (5) for converting the detection signal in the normal direction sent from the sensor body (3), (3)--.
) and a stepping motor (13), the rotational driving force of the stepping motor is transmitted via bevel gears (14) and (15) to the sensor body (
3), (3) - Power transmission device (
4). The sensor body (3), (3
) -・ is a stylus (3A) on the same circumference with diameter (D)
, (3B), (3C), and (3D) are arranged while maintaining a predetermined phase angle (90° in this example), and in this state they can rotate around the common rotation axis (8). In the illustrated embodiment, the workpiece (1) is configured as follows.
Since the direction of the normal line erected on the surface of is detected as the height difference (H) along the plane <X-Z> by two styluses, for example, stylus (3A) and (3B), the diameter ( D) 18o on the circumference.

The stylus (3A) and (3B) are arranged facing each other with a phase difference of . In addition, the direction of the normal to the surface of the workpiece (1) is set to a plane (Y-Z) perpendicular to the plane (X-Z).
), the stylus (3A
) and (3B), the stylus (3c) and (3D) are arranged facing each other so as to be orthogonal to the straight line connecting the axes of the probes (3c) and (3B).

Stylus (3A), (3B), (3C) and (3D
The four senna bodies (3), (3') - equipped with the workpiece ( In order to reduce the effect of big feed marks (cutting grooves) on the surface of the power transmission device (4),
) is rotatably supported via bevel gears (14) and (15), and is rotated at a predetermined angle (θ
) so that it can move along the free-form surface of the workpiece (1). To explain in more detail, the stylus of the sensor body (3), (3)-.
When the stylus is brought into contact with the free-form surface of the big feed mark, it is measured by the sensor body (3), (3) depending on whether it is in contact with the convex part or the concave part of the big feed mark. The differential (H) varies. However, since the big feed mark usually shows the periodicity of the feed of a cutter such as a ball end mill when cutting a workpiece, the stylus (3A), (3B), (3C) and (3D) is designated by the reference symbol (D) in FIGS. 2 and 5.
), for example, the stylus (3C) or (3D) placed adjacent to the stylus (3A) is occupied by the stylus (3A) before rotation due to the rotation of the rotation unit (16). The free-form surface (2) of the workpiece (1) is rotated by 90° clockwise or counterclockwise so that the
) along the individual sensor bodies (3), (3)
- Obtain measurement conditions that reduce the influence of big feed marks as much as possible by averaging the negative readings.

Here, as seen in FIG. 5, the sensor body (3),
(3) Four stylus needles (3A), (3B), (3G
) and (3D) are in contact with the free-form surface (2) of the workpiece (1), two stylus needles (3A) and (3B) arranged diagonally on the circumference with diameter (D) The free-form surface (2) of the workpiece (1) in the plane (X-Z) direction measured by can be regarded as a free-form curve expressed as y=f (x). Stylus (3A) and (3B) are y=f
When the stylus contacts the surface of the workpiece (1) indicated by (x), a differential (H) occurs between the stylus (3A) and (3B). Here, the distance between the stylus (3A) and the stylus (3B), that is, the diameter (D) of the circle, is made sufficiently small with respect to the curvature of the free-form surface (2) of the workpiece (1). If selected, the free-form surface between the stylus (3A) and the stylus (3B) is ymax
It can be regarded as a straight line. If this condition is satisfied, the slope (a) of the line segment sandwiched by the stylus (3A) and (3B) in FIG. 5 is given by the following equation 0.

...■ On the other hand, when a certain curve is given, the direction <2> of the normal line at any point (xl) on the curve is given by the following equation 0.

......■ From the above equations 0 and 0, the direction of the normal (Z) in the plane (X-Z) at the measurement point (xl) can be calculated as a a .

Figure 6 shows how the differential between the sensor bodies (3), (3)... changes with the rotation angle (θ) of the rotating unit (16) and the movement locus of the stylus (3A) and (3B). In FIG. 6, which is a related orthogonal coordinate diagram, the sensor body (3) when the rotation angle of the rotation unit (16) with the common rotation axis (8) as the rotation center is θ/2, (3)
When reading the measurement value of ・-・, the reading value becomes normal (
This is the indicated value of the first sensor device (10) necessary to calculate the direction of Z) or (Y). However, at the measurement point where the rotation angle of the rotation unit (16) is θ/2,
The pulsations caused by the big feed mark are superimposed. Therefore, in order to read accurate indicated values, it is necessary to eliminate the influence of pulsation. As a method for removing such noise, methods using a numerical processing moving average method and an electrical filter are known, and when implementing the present invention, it is possible to select and use an appropriate noise removal method from the above-mentioned noise removal methods. In the device of the present invention, as an electrical noise removal means, a high-cut filter, that is, a low-pass filter (9) as shown in FIG. 1 is installed for each sensor body (3). A pulsation elimination circuit is formed by connecting each one in series. In this way, the low-pass filter (
9), the difference between the indicated values of the stylus (3A) and the stylus (3B) + 3A-381, and the difference between the stylus (3C) and the stylus (30
) 17) By reading the difference in indicated value 13G-301, that is, the value of H in formula 0, as an absolute value, the influence of big feed marks can be considered in the signal processing device (12) equipped with the encoder (5). Under the removed conditions, the direction of the normal at the measurement point (xl) can be calculated.

Direction (Y) and (Z) of the normal line calculated in this way
), the direction of the grinding wheel rotation axis of the articulated robot (not shown) is corrected to create a state in which the axial direction of the grinding wheel matches the direction of the normals (Y) and (Z). In this way, ideal polishing conditions are obtained in which the axis of the grindstone is aligned with the normal to the free-form surface of the workpiece (1).

On the other hand, the free-form surface of the workpiece (1) is It is also possible to measure the waviness of 2). W
In addition, the waviness signals (3a) and (3b) caused by the big feed marks, which were removed as noise when calculating the direction of the normal line, are used as measurement values that indicate the size of waviness on the surface of the workpiece (1). Make use of it.

In this case, the gradient signal 13A-3B of the free-form surface for calculating the direction of the normal line at the measurement point (xl) is used.
Since 13G-301 and 13G-301 are unnecessary, the transmission path of the detected value shown in Fig. 1 is switched from the low-pass filter (9) side to the high-pass filter (11) side, and only the high frequency component corresponding to the big feed mark is transmitted. The signal processing device (12)
Send to.

Thus, by using the first sensor device (10), efficient polishing conditions can be achieved in which the direction of the axis of the grinding wheel is aligned with the normal to the free-form surface (2) of the workpiece (1). is maintained at all times, and any big feed marks remaining on the surface of the workpiece (1) are also removed at the same time.

In the above explanation, a contact type sensor with a stylus at the tip is used, but as an alternative, a non-contact type sensor such as a non-contact proximity switch, air micrometer, or photodiode can be used. It is also possible to do so.

On the other hand, the second sensor device (20) includes a plurality of sensor bodies (3) constituting the first sensor device (10).
, (3) ---, the roughness detection part (17) of the free-form surface (2) of the workpiece (1) is faced below the stylus (3A), (3B), (3C), and (3D). The surface roughness meter (7), for example, a capacitance type surface roughness measuring instrument, is supported by a fluid pressure cylinder device (6), for example, an air cylinder device, so as to be movable back and forth. The first sensor device (10) and the second sensor device (20) are joined into an integral structure via a known suitable joining means, but the plurality of sensors constituting the first sensor device (10) The common rotation axis (8) of the sensor bodies (3), (3) -. In order to maintain a predetermined amount (difference in height) between the two sensors, the surface roughness meter (7) constituting the second sensor device (20) is arranged parallel to the direction of the forward and backward stroke. ing.

First sensor device (10) and second sensor device (20)
The sensor unit consisting of the above-described sensor unit is freely attached to an articulated robot installed at a workpiece processing station via a chuck (not shown), and performs necessary detection operations according to the measurement procedure described above.

As can be understood from the above explanation, the direction of the normal line erected on the free-form surface of the workpiece by using the device of the present invention,
The height of the waviness caused by the big feed mark remaining on the free-form surface can be measured at the same time. Therefore, by correcting the polishing posture of the articulated robot that supports the grindstone based on these measured values, and more specifically, the direction of the grindstone rotation axis relative to the free-form surface of the workpiece,
Efficient polishing conditions can be maintained in which the rotating axis of the grindstone is always oriented in the normal direction to the free-form surface of the workpiece.

In this way, according to the present invention, polishing finishing processing is carried out quickly and accurately in a fully automatic manner, so that the rotating shaft of the grindstone, which has conventionally been a problem in the polishing finishing process of press molds, etc. The difficulty of directional control is completely eliminated. Furthermore, by using the device of the present invention, manual polishing and finishing by skilled workers can be omitted.
A remarkable effect is also exhibited in reducing the manufacturing cost of press molds.

Furthermore, in the present invention, the first sensor device for measuring the direction and waviness of the normal line erected on the free-form surface of the workpiece and the second sensor device for measuring the surface roughness of the workpiece are integrated. By selectively using these sensor devices, since they are connected to the structure, it is possible to quickly and accurately detect the characteristics of the free-form surface of the workpiece required for smooth and mirror finishing.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating the overall structure of the first sensor device, and FIGS. 2 and 3 are a front view and a bottom view illustrating the detailed structure of the first sensor device. Furthermore, FIG. 4 is a side view illustrating the overall structure of the second sensor device, FIG. 5 is an orthogonal coordinate diagram illustrating the operation procedure of the first sensor device, and FIG. 6 is a diagram showing the sensor. FIG. 3 is an orthogonal coordinate diagram illustrating the relationship with the rotation angle of the rotation unit. Also, Figure 7 shows
FIG. 2 is an explanatory diagram of a conventional polishing means for free-form curved surfaces of cotton. (1”) - Work, (2) - Work free song,
(3)---Sensor body, (4)---Power transmission value, (
5)---Encoder, (6)---Fluid pressure cylinder device, (7)---Surface roughness needle, (8)---Common rotation axis of sensor body, (10)--- first sensor device, (20
).--Second sensor device.

Claims (1)

[Claims] (1) A first sensor device that detects the direction of a normal to a free-form surface of the workpiece and the height of waviness remaining on the free-form surface, and a first sensor device that detects the surface roughness of the free-form surface. 2 sensor devices, wherein the first sensor device simultaneously connects a plurality of sensor bodies each having its stylus arrayed on the same circumference, and the plurality of sensor bodies. The second sensor device includes a rotationally driven power transmission device and a signal processing device including an encoder that calculates the direction of the normal line and the height of the undulation, and the second sensor device is connected to the first sensor device. It consists of a surface roughness meter that is supported so as to be movable back and forth by a fluid pressure cylinder device so that the surface roughness detection area of the workpiece is exposed below the stylus of the plurality of sensor bodies that make up the sensor body. A sensor unit characterized in that a common rotation axis of the plurality of sensor bodies is arranged parallel to a direction of a forward and backward stroke of the surface roughness meter.