KR20100034177A - Tool's length auto-measurement - Google Patents

Abstract

PURPOSE: A method and an apparatus for measuring the length and diameter of a cutting tool are provided to measure the length of the cutting tool and also to measure the diameter change of the cutting tool by obliquely photographing the tip of the cutting tool. CONSTITUTION: A method for measuring the length and diameter of a cutting tool comprises the steps of: initializing an image of a CCD camera with respect to the initial state of a cutting tool(S1), photographing the initial state of the cutting tool first with the CCD camera installed on one side of the cutting tool and extracting image information(S2), photographing the cutting tool again and extracting image information(S3), comparing and analyzing the first and second image information(S4), and determining the damage to the cutting tool(S5).

Description

Cutting tool length and diameter measuring method and cutting tool length and diameter measuring device {TOOL'S LENGTH AUTO-MEASUREMENT}

The present invention relates to a method and a measuring device for measuring the length and diameter of a cutting tool, and in more detail, in a machine tool equipped with a plurality of tools, by photographing the tool with a CCD camera, the tool length and tool according to the processing of the workpiece. The present invention relates to a method for measuring the length and diameter of a cutting tool and a measuring device for determining a degree of damage of a tool such as wear and damage by measuring a change in diameter.

In general, the cutting process using a machine tool is made using a variety of cutting tools, such as planing, side processing, hole processing, threading, etc., NC (numeric control) machine tool for this purpose, the tool housing provided on one side In the tool magazine, a number of cutting tools are placed and the spindle is machined by exchanging the tool for the required machining. This allows machine tools to run faster and faster with multiple tool storage.

The cutting tools used in the above-mentioned machine tools vary in length due to wear of the tool edge due to friction between the tool and the workpiece during machining, or damage or loss due to material unevenness of the workpiece during machining, equipment operation mistakes and external factors. Is generated.

This causes partial damage (wearing) and breakage due to the problem of the workpiece and the cutting tool during the machining of the workpiece, and causes serious failure as well as an operation error or an overload of the machine tool.

For example, when the cutting tool has a plurality of cutting edges, a plurality of tool inserts must be broken or broken to directly affect the workpiece (product). However, in the case of end mills, taps, drills, etc., since the number of cutting edges is small, an abnormality occurs directly on the workpiece and causes defects when the cutting edge breaks.

Therefore, a cutting tool used for a long time is a machining error occurs as much as the amount of wear occurs, it is necessary to measure the length of the cutting tool and to correct the worn length.

For this reason, conventionally, the damage detection or the length measurement of the cutting tool is performed when the sensor is operated by directly contacting the axis installed with the main shaft by using a limiter switch or a touch sensor installed inside the machine. There are a variety of methods using a method of converting a moving distance based on a viewpoint, a method of measuring based on a time when a laser scanned by a laser measuring device reaches a light receiving unit, an ultrasonic sensor, and the like.

In addition, a method for detecting breakage and wear by measuring a tool mounted inside the machine is already proposed in the previously proposed patent application No. 00: 'Measuring method for cutting tool length' or Patent Application No .: 1992 The name of -1869: known as 'automatic tool life measuring device for turning', etc., a detailed description thereof will be omitted.

The conventional techniques proposed as described above are impossible to measure due to the cutting chip because the device is installed inside the machine, or in the machine using the cutting oil, the cause of the error due to the oil and the scanning part or the light receiving part in the case of the laser sensor. Because the lens of the camera was not visible, it was inconvenient to check periodically or daily or repair it whenever an error occurred.

In addition, the installation space of the workpiece is limited due to the measuring device installed inside the machine and there was a disadvantage that a separate device for cleaning the cutting chip or other contaminant must be added to the measuring device.

In addition, various measures should be considered for the protection of control and electrical devices including data signals, and are difficult to protect from these pollutants, difficult to precisely measure cutting tools, as well as a drastic deterioration in durability. Subsequent limitations have been followed, which left problems such as irregular workpiece dimensions or product defects.

Due to these various problems, the treatment to solve this problem is very poor, and the risk of malfunction of the measuring device increases, which requires urgent improvement.

The present invention is a method for measuring the length by photographing the cutting tool (T, Ta) for the machine tool with the CCD camera 10, the initializing the image of the CCD camera 10 for the initial state of the cutting tool Step S1; Photographing an initial state of the cutting tool with a CCD camera provided at one side of the cutting tool and extracting the image information having pixel coordinate values (S2); After the cutting tool is used, secondary imaging by the CCD camera to extract image information having coordinate values in pixel units (S3); Comparing the primary image and the secondary image information of the cutting tool extracted as described above by the control means (S4), and determining whether the damage due to the wear of the cutting tool (S5) It is to propose a method for measuring the length and diameter of a cutting tool.

The cutting tool length and diameter measuring method and measuring device proposed by the present invention compare the cutting tool before and after the cutting process by using a CCD camera as a pixel-by-pixel image to determine the degree of wear of the cutting tool damage to the cutting tool The presence or absence can be measured quickly and accurately, and this can be corrected or replaced at an appropriate time to reduce the defective rate of the workpiece due to the cutting process and improve the operating efficiency of the machine tool.

In addition, the present invention can measure the length of the cutting tool as well as measuring the change in diameter by photographing the tip of the cutting tool at an angle with a CCD camera, the damage and damage of the cutting tool can be more precisely measured There is this.

In another aspect, the present invention is to prevent the damage and damage of the workpiece as well as the cutting tool, the automated machine tool such as NC and CNC machine tool is accompanied with the advantage to enable the automation of a more stable environment.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and embodiments of the present invention are provided to enable those skilled in the art to more easily understand the present invention. In describing the present invention, when it is determined that the detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Like reference numerals in the drawings refer to like elements.

1 is a flow chart schematically showing a method for measuring the length and diameter of a cutting tool according to a preferred embodiment of the present invention, Figure 2 is a view showing the coordinates of the image information taken by the CCD camera of the present invention.

Referring to the drawings, the method for measuring the length and diameter of the cutting tool of the present invention is a method for measuring the length of the cutting tool (T, Ta) for the machine tool by measuring with a CCD camera 10, Initializing an image of the CCD camera 10 with respect to an initial state (S1); Photographing an initial state of the cutting tool with a CCD camera provided at one side of the cutting tool and extracting the image information having pixel coordinate values (S2); After the cutting tool is used, secondary imaging by the CCD camera to extract image information having coordinate values in pixel units (S3); Comparing the primary image and the secondary image information of the cutting tool extracted as described above by the control means (S4), and determining whether the damage due to the wear of the cutting tool (S5) It is done.

The present invention is a measuring device for measuring the length and diameter of the cutting tool by the above steps consists of the following configuration.

3 is a front view schematically showing a length and diameter measuring device of the cutting tool according to the present invention, Figure 4 is a front view showing a measuring device for measuring the change in the diameter of the cutting tool according to another embodiment of the present invention.

Referring to FIG. 3, the length and diameter measuring device of the cutting tool of the present invention is a device for measuring the length of the cutting tool (T, Ta) for the machine tool by measuring the CCD camera 10, the cutting tool CCD camera 10 for taking a picture of the external appearance and extracting the pixel unit image; A bracket 20 installed at one side of the tool housing of the machine tool to support the CCD camera; Control means 30 for comparing the primary image and the secondary image information of the cutting tool taken by the CCD camera to determine whether the damage due to wear.

Preferably, referring to FIG. 4, the length and diameter measuring device of the cutting tool according to another embodiment of the present invention, the CCD camera 10 at an angle (B) at an angle toward the end of the cutting tool. Characterized in that it is installed.

The above is described in more detail as follows.

First, the present invention initializes the image of the CCD camera 10 with respect to the initial state of the cutting tool and prepares to photograph (S1).

In the cutting tool used for the first time, information such as the tool number, the tool name and type of the tool, the length and diameter of the tool, and the like stored in the tool data section of the NC device are transmitted to the controller and stored in the data section. Then, the initial image is taken using the CCD camera 10 to obtain the length and diameter of the cutting tool (T, Ta). In other words, the position of the corresponding pixel of the image is stored and initialized in accordance with the basic information of the tool, that is, the tool length, the diameter, and the like previously stored at the position.

Subsequently, when a tool measurement instruction is given from the NC machine tool, the CCD camera first photographs the initial state of the cutting tool and extracts the image G1 information having coordinates in pixel units (S2). Coordinates are extracted by creating a tool template that images the initial state of the cutting tool.

Here, the first cutting tool (T, Ta) is used to receive the length or diameter information of the tool from the NC machine tool to correct and match the position information and the length of the coordinate value to perform the adjustment work. In other words, the unit length applied to each cell of the coordinate system varies slightly depending on the installation position of the CCD camera. Therefore, the measurement data should be corrected by using the reference cutting tool and then corrected by this correction value. Using the correction value, the positional relationship between the camera position and the tool has unique length information for each cell.

The cutting tool used after the correction is completed as described above, the correction operation for the length deviation is automatically enabled.

Next, after the cutting tool is used, the tool after the cutting operation is returned to the standby port is photographed by the CCD camera and extracted as image information having a coordinate value in pixel units (S3).

After processing the workpiece by using the cutting tool, in order to measure the change in the state, that is, the change or wear or damage of the cutting edge due to the machining friction, the image G2 of the tool photographed secondly by the camera is applied to each cell. When positioned, it is possible to convert the position information of the cell with respect to the end of the tool.

2, the image of the cutting tool taken by the CCD camera is located in the virtual X-axis and Y-axis coordinate system, and the relative position of each cutting tool is determined by the position of this coordinate.

The primary image G1 and the secondary image G2 information of the cutting tool extracted as described above are analyzed by the control means 30. (S4) In this case, the primary image G1 and the secondary image are analyzed. The difference value (A) of (G2) determines whether or not the replacement of the cutting tool is caused by wear.

In this way, the control means 30 compares the distance data converted from the initial image G1 of the cutting tool with the information of the image G2 after processing and the initial measurement data to determine whether it is within a tolerance range and damages the cutting tool. To determine whether it is damaged or replaced. (S5)

At this time, if it is within the tolerance range, the process returns to step S2 and repeats the above process, or if the comparison value is out of the tolerance range, the cutting tool is regarded as damaged or broken and an alarm is signaled (S6). This can be done to correct the length so that the tip of the tool matches the beginning or to replace a damaged cutting tool. This calculates the degree of wear by comparing the shape of the tool image after the coordinate comparison of the tool template and the set threshold value reference operation in the overall image of the cutting tool.

For example, when measuring the same cutting tool, the coordinate value of the end point of the tool at the time of the first measurement is stored in a database and represented as a variable of the length of the coordinate value, which is converted to measure the length of the tool. In addition, the cutting tool calculates an error range of the length by converting the coordinates and the deviation of the initial measurement, whether before cutting or after cutting.

The CCD camera 10 is connected to the control means 30 and the image information is transmitted, by comparing the image information by the control means to determine the degree of wear and replacement.

Although the installation position of the CCD camera 10 varies slightly depending on the rotation radius and the performance of the cutting tool, it is preferable that the CCD camera 10 is installed close to have a clear business card in the pixel (pixel) of the image when the camera is photographed. Do not interfere with the tool.

The cutting tool (T) is mounted to a tool holder (2) provided in the machine tool, as shown in Figure 2, to support the CCD camera 10 to not shake the bracket of the machine tool or the peripheral structure of the cutting tool ( 20) to mount the CCD camera. The brackets are installed side by side in the longitudinal direction of the cutting tool and the CCD camera is installed toward the center of the tool at one end of the cutting tool, and is installed at an angle or at an angle to the right angle from the axis according to the shape of the cutting tool.

Alternatively, when the length of the cutting tool varies, it is difficult to measure with one camera, so the number of installation of the camera is determined to be able to measure from the minimum length to the maximum length according to the difference in length, and the cutting tools (T, T1 At least one or a plurality of CCD cameras 10a, 10b, and 10c are provided according to the length of T2.

In the present invention, as shown in Figure 4, the cutting tool Ta is a CCD camera (10d) to measure the change in the rotation radius of the cutting edge, that is, the change in the diameter of the cutting tool, such as a face cutter mainly used in milling machine tools, etc. It is installed at an oblique angle B toward the end of the cutting tool.

That is, by establishing a calculation formula for the inclination angle and the image length of the CCD camera 10d, the change can be measured in the same manner as the calculation variable for the image length. In other words, by establishing the outer portion of the photographed image outer diameter with respect to the inclination angle of the CCD camera as the coordinate value of the cell, the outer height and distance from the center distance are calculated. Correction of the error is made in the same manner as correction of the length.

The algorithm for damage detection of the cutting tool image records and stores the coordinates where the last data is located on the coordinates in the standard pixel section with respect to each tool. After use, the length of the tool identifies the point in the coordinates of the pixel where the last data obtained by imaging with a CCD camera is located.

Here, the distance per pixel unit is set as a variable according to the position of the camera and the diameter of the tool, and the distance per resolution of the CCD camera is determined. Of course, advances in camera technology allow us to subdivide the hardware pixel into more fine-grained software, and the finer the pixel, the more precise the tool length data can be obtained.

Pixels of the cutting tool image taken by the CCD camera can be located in a number of units in the width and length of the width, and the reason for the same result is that the maximum diameter of the tool is always located at the center of the tool axis. Because. Due to the regularity of these tools, length variables can be obtained.

Alternatively, measurement can be performed even when the cutting tool is installed eccentrically from the center of the shaft. This allows continuous data to be obtained by taking an image (video) while the camera rotates once about the center of the tool axis, regardless of the eccentric cutting tool insert or cutting edge position. It is the outer diameter of this tool.

As a result, the present invention can measure the length and diameter at the same time, and can improve the operation rate of the machine by increasing the cutting time by reducing the non-cutting time as much as possible compared to the direct contact method.

The cutting tool measuring apparatus of the present invention, for example, the installation position of the CCD camera in a magazine or magazine such as a CNC machine tool or a CNC machine tool, a standby position for exchanging the tool, that is, a more stable shooting and A clear image can be obtained. Increasing the resolution of the camera also enables more accurate measurement errors and wear conditions to be detected, allowing cutting tools to be corrected or replaced at the right time.

In addition, the control means 30 is provided with a control unit for controlling the processing and overall operation of the image information taken by the camera as shown in Figure 5, and a database 32 for storing and managing the information data processed by the control unit . In addition, the communication unit 34 in charge of communication with the NC or CNC machine tool, and the illumination unit 36 for illuminating the cutting tool when shooting with the CCD camera to sharpen the image is provided.

1 is a flow chart schematically showing a method for measuring the length and diameter of a cutting tool according to an embodiment of the present invention.

Figure 2 is a view showing the coordinates of the image information taken by the CCD camera of the present invention.

Figure 3 is a front view schematically showing a length and diameter measuring device of the cutting tool according to the present invention.

Figure 4 is a front view showing a measuring device for measuring the diameter of the cutting tool according to another embodiment of the present invention.

Figure 5 schematically shows the control means of the cutting tool measuring apparatus according to the present invention.

Claims (3)

In the method of measuring the length by photographing the cutting tool (T, Ta) for the machine tool with the CCD camera 10, Initializing an image of the CCD camera (10) with respect to the initial state of the cutting tool (S1); Photographing an initial state of the cutting tool with a CCD camera provided at one side of the cutting tool and extracting the image information having pixel coordinate values (S2); After the cutting tool is used, secondary imaging by the CCD camera to extract image information having coordinate values in pixel units (S3); Comparing the primary image and the secondary image information of the cutting tool extracted as described above by the control means (S4), and determining whether the damage due to the wear of the cutting tool (S5) Method for measuring the length and diameter of cutting tools. In the method of measuring the length by photographing the cutting tool (T, Ta) for the machine tool with the CCD camera 10, A CCD camera 10 which photographs the exterior of the cutting tool and extracts an image of a pixel unit; A bracket 20 installed on one side of the tool housing of the machine tool to support the CCD camera; Comparing and analyzing the primary image and the secondary image information of the cutting tool taken by the CCD camera comprising a control means (30) for determining whether damage due to abrasion of the cutting tool length and diameter. The method according to claim 1 or 2, The method of measuring the length and diameter of the cutting tool and the length and diameter measuring device of the cutting tool, characterized in that the CCD camera 10 is installed obliquely at a predetermined angle (B) toward the end of the cutting tool.

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