JP7408142B2 - Surface roughness prediction method and surface roughness prediction device of workpiece by machining with rotary cutting tool - Google Patents

Description

The present invention relates to a surface roughness prediction method and a surface roughness prediction device for predicting the surface roughness after machining of a workpiece surface that is machined by the cutting surface of a rotary cutting tool such as a rotary grindstone. .

Patent Document 1, Patent Document 2, and Patent Document 3 disclose techniques for photographing the grinding surface of a rotary grindstone in order to check the condition of the grinding surface.

Japanese Patent Application Publication No. 2004-42158 Japanese Patent Application Publication No. 2004-45078 Japanese Patent Application Publication No. 2013-2810

For example, as a workpiece is processed, changes occur on the grinding surface of a rotary grindstone, such as abrasive grains wearing out or falling off, or foreign matter (chips, etc.) adhering to or accumulating on the grinding surface. When such a change occurs, the surface roughness of the processed surface of the workpiece decreases. For this purpose, a method of photographing the abrasive surface and inspecting the condition of the abrasive surface is considered, but in Patent Document 1, Patent Document 2, and Patent Document 3, the surface roughness of the processed surface after processing It is difficult to predict.

An object of the present invention is to provide a surface roughness prediction method and a sharpness prediction device that enable prediction of the surface roughness of a processed surface of a workpiece after processing, prior to processing the workpiece.

In order to achieve the above object, in the surface roughness prediction method of the present invention, the entire circumference of the cutting surface of a rotary cutting tool is photographed while the rotary cutting tool is rotating, and the image data is used to describe the cutting surface of the image data. The method is characterized in that the surface roughness of the processed surface of the workpiece is predicted by compressing it in the workpiece feeding direction according to the relationship between the circumferential length and the feed rate of the workpiece.

The surface roughness prediction device of the present invention also includes a photographing means for photographing the entire circumference of the cutting surface of the rotary cutting tool while the rotary cutting tool is rotating, a storage means for storing photographed image data, and a storage means for storing photographed image data. Compressing means compresses the image data in the workpiece feed direction according to the relationship between the length of the image data in the circumferential direction of the cutting surface and the feed amount of the workpiece; The present invention is characterized by comprising a prediction means for predicting the degree.

Therefore, in the present invention, for example, the entire circumference of the cutting surface of a rotary cutting tool is photographed while the rotary cutting tool is rotating. Then, the photographed image data is compressed in the workpiece feed direction according to the relationship between the circumferential length of the cutting surface and the workpiece feed amount, and the surface roughness of the workpiece surface is calculated based on the compressed image data. degree is predicted. Therefore, since the surface roughness of the workpiece is predicted before machining the workpiece, there is no need for test machining before machining the workpiece, measurement after test machining, or measurement after machining the actual workpiece. Able to perform work efficiently.

According to the present invention, the surface roughness of the surface to be machined of the workpiece can be predicted prior to machining the workpiece, thereby eliminating the need for test machining before machining the workpiece, and achieving the effect that machining work can be performed efficiently. .

The front view which shows the cutting part by a rotary grindstone. FIG. 2 is a sectional view showing the photographing device. A simplified diagram showing the pitch of the grinding surface of the rotary whetstone. FIG. 2 is a block diagram showing the electrical configuration of the inspection device. A flowchart showing the operation of measuring the surface roughness of a machined workpiece. 2 is a flowchart showing the operation of predicting the surface roughness of a workpiece by machining with a rotary grindstone. FIG. 3 is a schematic diagram showing the relationship between image data and the feed amount of a workpiece.

(Embodiment)
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described based on the drawings. This embodiment is embodied in a cutting machine in which the rotary cutting tool is a rotary grindstone.

As shown in FIG. 1, the cutting machine of the embodiment includes a table 12 supported on a bed 11 so as to be movable in the X-axis direction (horizontal direction) indicated by an arrow P. Movement of the table 12 in the X-axis direction is driven by a table movement motor (not shown). A workpiece 100 is placed on the top surface of the table 12. Therefore, the workpiece 100 is processed and fed in the direction of arrow P, which is the X-axis direction.

A grindstone shaft 13 is supported by a column (not shown) that is moved in the front-rear direction (Z-axis direction) on the bed 11 so as to be movable up and down (in the Y-axis direction). This grindstone shaft 13 is driven up and down by a grindstone feed motor (not shown). A rotary whetstone 14 as a rotary cutting tool is supported on the whetstone shaft 13, and this rotary whetstone 14 is rotationally driven in one direction by a whetstone rotation motor 15 shown in FIG. The rotation speed of the rotary grindstone 14 is, for example, 1800 revolutions per minute or 3600 revolutions per minute, but this rotation speed can be set arbitrarily.

The outer peripheral surface of the rotary grindstone 14 serves as a grinding surface 14a serving as a cutting surface. When the rotary grindstone 14 is rotated, the upper surface of the workpiece 100 is cut by the grinding surface 14a. This surface to be cut is defined as the surface to be machined.

As shown in FIGS. 1 and 2, a photographing device 21 as a photographing means is installed at a side of the rotary grindstone 14. The photographing device 21 is moved up and down (moved in the Y-axis direction) and back and forth (moved in the Z-axis direction) together with the rotary grindstone 14 . This photographing device 21 has a light path 22, and the path 22 has a first path 22a and a second path 22b that intersects with the first path 22a. A camera 23 having a CCD (solid-state imaging device) is provided at the end of the second path 22b.

A measuring device 50 serving as a measuring means for measuring the surface roughness of the machined surface, which is the cut surface of the workpiece 100, and outputting the measured data is disposed on the side of the rotary grindstone 14. This measuring device 50 is moved together with the rotating grindstone 14 in the Z-axis direction and the Y-axis direction.

A reflective light-transmitting member 24, such as a prism, having a light reflecting function and a light transmitting function is arranged between the first path 22a and the second path 22b. A first lamp 25 is provided at the end of the first path 22a. The first lamp 25 is configured to irradiate light with a wavelength in a specific region, and in this embodiment, the first lamp 25 irradiates light with a wavelength that makes the abrasive grains 14b on the abrasive surface 14a noticeable.

On the second path 22b, an illumination dome 26 is arranged between the reflective transparent member 24 and the abrasive surface 14a. An opening 27 for the second path 22b is formed in the illumination dome 26. A plurality of second lamps 28 are provided on the inner surface of the illumination dome 26 to provide area illumination in front of the illumination dome 26. This second lamp 28 is adapted to radiate light of a wavelength in a specific region, and in this embodiment, radiates light of a wavelength that makes the abrasive surface 14a stand out.

Then, the beam-shaped light from the first lamp 25 is reflected by the reflective translucent member 24, passes through the opening 27, and is irradiated onto the abrasive surface 14a. A reflected image of the irradiated light passes through the reflective transparent member 24 and reaches the camera 23, whereby an image of the abrasive grains 14b on the abrasive surface 14a is acquired. Further, the light from the plurality of second lamps 28 is irradiated onto a wide area range of the grinding surface 14a of the rotary grindstone 14. The reflected image of this light also passes through the reflective transparent member 24 and reaches the camera 23, whereby an image of the abrasive surface 14a is acquired.

The data of the photographed image is stored in a storage unit 33 of the control device 31, which will be described later.
FIG. 2 shows the electrical configuration of this embodiment. The control device 31 includes a central processing unit 32 as a prediction means and a storage section 33 as a storage means. The cutting machine of this embodiment is operated by executing the program stored in the storage unit 33 under the control of the central processing unit 32. The motor 15 and camera 23 are connected to the control device 31 . Further, an encoder 34 is connected to the control device 31 . As shown in FIG. 3, the encoder 34 generates an allocation pulse for each rotation angle of the rotary grindstone 14 at a predetermined equal pitch (allocation pitch δ) as shown in FIG. Then, in response to the pulses, the camera 23 opens the shutter at predetermined intervals to take pictures. The number of assigned pulses is, for example, 1000 per rotation of the rotary grindstone 14, but the number of assigned pulses is not limited and can be set arbitrarily depending on the encoder used.

A display device 51 made of a liquid crystal display or the like displays the control results by the control device 31 as an image.
Next, the operation of this embodiment will be explained with reference to the flowcharts of FIGS. 5 and 6. In this flowchart, a program stored in the storage unit 33 of the control device 31 progresses under the control of the central processing unit 32.

When machining of the workpiece 100 is completed in steps S (hereinafter simply referred to as S) 1 and S2 in FIG. 5, the surface roughness of the workpiece surface of the workpiece 100 is measured by the measuring device 50 in S3, and in S4, The surface roughness data obtained is stored. Next, in S5, machining data indicating machining conditions such as the hardness of the workpiece 100 and the number of the rotary grindstone 14 is stored. That is, here, the correlation between the surface roughness of the processed surface of the workpiece 100 and the processing conditions by the grinder is recorded.

Note that the work shown in FIG. 5 and FIG. 6 described later is performed on a sample basis, for example, before processing a plurality of workpieces 100, and is not performed every time before processing each workpiece 100. .

Next, in S11 of FIG. 6, the rotary grindstone 14 is moved to the position of the dresser 16. Then, the dresser 16 performs dressing of the grinding surface 14a of the rotary grindstone 14 for a predetermined period of time. After the predetermined period of time has passed, the end of dressing is determined in S12, and in S13, the rotary grindstone 14 leaves the position of the dresser 16 and is rotated in one direction.

In S14, the abrasive surface 14a is photographed by the camera 23 in accordance with the output timing of the allocation pulse output from the encoder 34, and is stored in the storage unit 33. As described above, the allocation pulses are outputted, for example, 1000 times each time the rotary grindstone 14 rotates once, and the total number of allocation pulses per rotation is defined as n.

In S15, it is determined whether the rotary whetstone 14 has rotated to the n+1 position, that is, it is determined whether the rotary whetstone 14 has rotated by one rotation plus 1/n, and is rotated to the n+1 position. Then, photographing is executed in S16, and the image data is stored in the storage section 33. In S17, it is determined whether or not n times of photographing has been completed. Until the number of images reaches n times, that is, until the rotary grindstone 14 rotates n times, the positions of the grinding surface 14a assigned by the encoder 34 are sequentially imaged. Therefore, n pieces of image data D shown in FIG. 7 are obtained.

Then, as the n times of photographing are completed, in other words, as the photographing of the entire grinding surface 14a of the rotary whetstone 14 is completed, after the determination in S17, in S18, one revolution of the rotary whetstone 14 is completed. The per feed amount β is obtained. Next, in S19, the n pieces of image data D are connected so as to be continuous along the rotating direction of the rotary grindstone 14, in other words, along the feeding direction of the workpiece 100.

Next, in S20, as shown in FIG. 7, n pieces of image data D are compressed according to the feed amount β of the workpiece 100 per rotation of the rotary grindstone 14. That is, the n pieces of image data D represent images having a length α corresponding to one revolution of the grinding surface 14a of the rotary grindstone 14.

Here, the workpiece 100 is fed by a feed amount β for one revolution of the rotary grindstone 14. The relationship between the total circumference length α of the grinding surface 14a and the feed amount β of the workpiece 100 per rotation of the rotary grindstone 14 is as follows.
α＞β
Therefore, the shape of the abrasive surface 14a expressed by conditions such as the density of the abrasive grains 14b around the entire circumference of the abrasive surface 14a is compressed to the length of the feed amount β of the work 100, and the shape of the abrasive surface 14a is compressed to the length β of the feed amount β of the work 100. It is transferred onto the processed surface γ with a length of 100 min. Therefore, in S20, the image data of the length of one revolution of the rotary grindstone 14 is compressed to the length of β/α along the circumferential direction of the rotary grindstone 14 and the feeding direction of the workpiece 100.

In S21, the compressed image data and the processed data obtained in S5 of FIG. 5 are obtained. Then, the surface roughness of the surface to be processed of the workpiece 100 is predicted from this processing data and the compressed image data. For example, the type of grindstone 14, the hardness of the workpiece 100, etc. are directly related to the level of surface roughness of the surface to be machined. Therefore, based on these relationships, the surface roughness of the processed surface can be accurately predicted.

In S21, the predicted surface roughness is displayed on the display device 51.
Therefore, this embodiment has the following effects.
(1) The surface roughness of the processed surface of the workpiece 100 after processing can be predicted before starting processing of the workpiece 100. Therefore, there is no need to perform test machining of the workpiece 100 before machining the workpiece 100, measure the surface roughness after the test machining, or measure the surface roughness each time the workpiece surface is cut. become. Therefore, the workpiece 100 can be processed efficiently.

(2) Since the surface roughness of the processed surface of the workpiece 100 after processing can be predicted by only rotating the rotary grindstone 14 once, the prediction work can be performed efficiently in a short time.
(Example of change)
Each of the embodiments described above can be modified and implemented as follows. Each embodiment and the following modification examples can be implemented in combination with each other within a technically consistent range.

- Use a tool other than the rotary grindstone 14 as the rotary cutting tool, such as a milling cutter or a hob. In milling cutters and hobs, the cutting edge is the cutting surface.
・To predict the surface roughness of the workpiece surface by photographing the grinding surface of a rotary grindstone with the side surface as the grinding surface.

- In the above embodiment, when photographing the grinding surface 14a, the rotary grindstone 14 is rotated and photographed by shifting it by n+1, but the photographing is performed by shifting by n-1.
- When photographing the grinding surface 14a, the photograph should be taken with a shift of at least 12 allocation pitches for each rotation of the rotary grindstone 14.

- When the rotational speed of the rotary whetstone 14 is low, in photographing with the camera 23, as the rotary whetstone 14 rotates, images of the grinding surface 14a at each allocation position are sequentially executed. Therefore, by rotating the rotary grindstone 14 once, the entire grinding surface 14a can be photographed.

- Photographing a part of the grinding surface 14a of the rotary grindstone 14 and predicting the surface roughness based on the photographed data.
- In the embodiment, the image data for one revolution of the grinding surface 14a is compressed to be the feed amount β of the workpiece 100 per rotation of the rotary grindstone 14, but the compression ratio of the image may be changed to another ratio, for example, To simply multiply the image data D for one rotation of the abrasive surface 14a by an integral number such as 1/1000.

- Continuously photographing images of the abrasive surface 14a, for example, for one round, and predicting the surface roughness based on the image data.
(Other technical ideas)
The technical idea understood from the above embodiment is as follows.

(A) The method for predicting surface roughness of a workpiece by machining with a rotary cutting tool according to claim 1, wherein the rotary cutting tool is a rotary grindstone, and the cutting surface is an abrasive surface on the outer periphery of the rotary grindstone.
(B) As stated in the above technical concept (A), in which the grinding surface of a rotary whetstone is allocated to a plurality of areas, the grinding surface is photographed at each allocated position, and the image data is continuous along the circumferential direction of the grinding surface. A method for predicting the surface roughness of a workpiece by machining a rotary cutting tool.

(C) The method for predicting the surface roughness of a workpiece by machining a rotary cutting tool according to the above technical idea (A), in which the abrasive surface is photographed before the workpiece is processed and after the abrasive surface is dressed.
(D) The method for predicting surface roughness of a workpiece processed by a rotary cutting tool according to claim 1, wherein the photographing is performed over the entire circumference of the grinding surface of the rotary grindstone.

14...Rotating grindstone 14a...Abrasive surface 14b...Abrasive grains 21...Photographing device 23...Camera 31...Control device 34...Encoder 100...Workpiece D...Image data α...Length β...Feed rate γ...Working surface

Claims (2)

A compressed image is created by photographing the cutting surface of a rotary cutting tool while the rotary cutting tool is rotating, and compressing the image data in the workpiece feeding direction according to the relationship between the circumferential length of the cutting surface and the feed rate of the workpiece. A method for predicting the surface roughness of a workpiece by machining with a rotary cutting tool, which is characterized by predicting the surface roughness of the workpiece surface based on data . Photographing means for photographing the cutting surface of the rotary cutting tool while the rotary cutting tool is rotating;
a storage means for storing photographed image data; a compression means for compressing the stored image data in the workpiece feed direction according to the relationship between the length of the image data in the circumferential direction of the cutting surface and the feed amount of the workpiece;
An apparatus for predicting the surface roughness of a workpiece by machining a rotary cutting tool, comprising a prediction means for predicting the surface roughness of a workpiece surface based on compressed image data.