JP2012037431A - Position measurement device and position measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the position of a measurement part of an object to be measured without touching the measurement part.SOLUTION: A cutting edge position measurement device 1 includes a focus type ultrasonic sensor 2b which is arranged at a predetermined distance from a cutting edge 5 of a micro drill 4 dipped in liquid, and emits an ultrasonic wave to the cutting edge 5 and converges it on a focus, and a detection part 2 which is at a predetermined distance from the cutting edge 5 and detects a reflected wave reflected by the cutting edge 5 positioned at the focus. Further, the cutting edge position measurement device includes a measurement part 3 which measures the position where the cutting edge 5 of the micro drill 4 enters the focus based upon change in amplitude of the reflected wave detected by the detection part 2.

Description

  The present invention relates to a position measuring apparatus and a position measuring method suitable for application to, for example, measuring the position of a cutting edge of a micro drill immersed in a liquid.

  2. Description of the Related Art Conventionally, a blade edge position measuring device that measures a position where a blade edge enters by contacting a blade edge of a micro drill is generally used. As such a blade edge position measuring device, for example, a device called a base master or tool master (registered trademark) of Daishowa Seiki Co., Ltd., or an ultra-precision sensor of N.E. Some of these blade edge position measuring devices have a small pressing force of about 0.1 g when contacting the blade edge, and are used to measure the edge position of a micro drill that is easily broken even with a slight load. Here, the following patent document 1 is submitted about the contact-type blade-tip-position measuring apparatus.

  Patent Document 1 discloses a blade edge position measuring apparatus that can reliably and highly accurately measure a blade edge position of a micro drill or the like having a very thin blade edge. This blade edge position measuring device includes an L-shaped strain generating member and a displacement measuring sensor. The strain generating member has an upright portion and a beam portion fixed on the pedestal, and two carcass holes connected by long grooves are arranged in a row on the side surface of the beam portion. A pair of meat parts facing the upper and lower parts of the meat hole are set to be extremely thin and have a diaphragm shape. Here, the displacement measuring sensor is used to measure the amount of displacement of the tip of the beam portion, and has a diaphragm shape with a very thin meat portion. For this reason, the pressure applied to the micro drill is very small, and the micro drill is not bent or broken by the pressure received from the beam portion.

  On the other hand, as an optical non-contact measuring method using an optical system such as a metal microscope, the following method has been researched and developed in order to measure the position of the cutting edge while making no contact with the cutting edge of the micro drill.

  Patent Document 2 discloses a technique related to a non-contact cutting edge position measuring method of a micro tool using a contrast peak. In recent years, in the fields of optoelectronic components and medical components, new processing that produces high added value by micro processing using micro end mills, drill centers, drill reamers, etc. (micro tools) with a diameter of 1 mm to several tens of μm It is attracting attention as a technology. In this research, by using the optical system of a metal microscope, by obtaining an image from the bottom blade side of the micro tool and measuring the contrast peak, it is possible to cope with micro tools of various blade shapes, and the position of the blade edge in the three axis directions is 1 Cutting edge position measuring instruments that can be measured with two optical systems have been manufactured. The main findings obtained are as follows.

(1) When the ground plane is a detection target, and the contrast calculation range is 3 μm or more, the detection accuracy is σ = 0.05 μm or less,
(2) By making the direction of the contrast detection line perpendicular to the grinding marks of the micro tool, bright and dark stripes with a high spatial frequency can be obtained, and the detection accuracy of the repeated position is high.
(3) When the results of (1) and (2) described above are used, the detection accuracy of the repeated position is 2σ = ± 0.036 μm with a φ0.04 mm square-air end mill, and 2σ with a nose R 0.05 mm ball end mill. = ± 0.019 μm, better than the existing edge position measuring instrument.

  Patent Document 3 discloses a method for measuring the edge position of a micro drill.

JP 2002-377040 A Nobuya Suzuki, Kazuhide Kamiya, Yukio Maeda, Yusuke Kajima, Shun Nomura (Toyama Prefectural University), Journal of Precision Engineering (CD-ROM) Volume (Date of issue): Vol.75No.11P.1329-1334 ( 2009.11.05) Development of blade position measurement device using incoherent light (2nd report) Prototype of on-machine device and evaluation by machining experiment Authors: Shinya Suzuki, Kazuhide Kamiya, Yukio Maeda, Shun Nomura (Toyama Prefectural University) : Proceedings of the Annual Meeting of the Japan Society for Precision Engineering, Issue Page (Date of Publication): Vol.2010 Spring (CD-ROM) Page.ROMBUNNO.L32 (2010.03.01)

  By the way, in the conventional contact measurement method, it is said that the drill life at the time of drilling is reduced to about 80% because the cutting edge of the micro drill contacts the measurement surface of the measuring device. Further, since the diameter of the micro drill is as thin as 10 to several hundreds of micrometers, the cutting edge is broken only by applying a load of about several g to the cutting edge from the lateral direction. For this reason, when the contact-type measuring device is installed to be inclined with respect to the drill, or when the drill is brought into contact with the measurement surface inadvertently by the user, the micro drill sometimes breaks easily.

  In addition, since the price of a micro drill having a diameter of about 10 μm is as high as tens of thousands of yen / book, damage to the micro drill or a decrease in the service life is not only a reduction in processing efficiency, It will also increase the processing cost. For this reason, the measuring method which can measure a drill position, without contacting a micro drill is desired.

  In addition, as described above, although optical measurement methods have been researched and developed for non-contact measurement methods, it is difficult to accurately measure the position of the blade edge in wet or semi-dry processing where oil droplets adhere to the blade edge. It is guessed that. Further, it can be inferred that the use of an optical system of a metal microscope complicates the measuring apparatus itself. Although contact-type methods and non-contact-type methods using light have been developed and put to practical use in this way, portable non-contact-type edge position measurement that can be easily placed on a machine tool to measure the edge position of a micro drill The current situation is that no device exists.

  Further, hole drilling by micro drills has been widely used in the medical device field, the electronic field, the precision machine field, and the like, and it is expected that the demand will further increase in the future. Examples of microdrill processing include nozzles of electronic fuel injection devices and multilayer printed boards. For this reason, improvement in processing efficiency and economic efficiency are desired.

  The present invention has been made in view of such a situation, and an object thereof is to measure the position of a measurement site without contacting the measurement site of an object to be measured.

The present invention is arranged at a focal point by an ultrasonic source that is arranged at a predetermined distance from a measurement site of an object to be measured immersed in a liquid and radiates an ultrasonic wave to the measurement site and collects the focal point. The reflected wave reflected by the measurement site to be detected is detected at a predetermined distance from the measurement site.
And based on the change of the amplitude of a reflected wave, the position where the measurement site | part of the to-be-measured object approached into the focus is measured.

  By doing in this way, it became possible to measure the position of a measurement part, without contacting the measurement part of a to-be-measured object.

  According to the present invention, since the position where the measurement site has entered is measured with a predetermined distance from the measurement site of the measurement object, the measurement site is not damaged. In addition, since the position where the measurement site has entered the ultrasonic focal point can be measured with the minimum configuration, for example, even if the measurement site of the measurement object is immersed in water or oil, the position of the measurement site can be determined. It is possible to measure. For this reason, there exists an effect that it can measure even if it is in the state where the water | moisture content and oil droplet which adhered to the measurement site | part adhered, making a device a portable type structure.

It is a block diagram showing an example of composition of a blade edge position measuring device in a 1st embodiment of the present invention. It is explanatory drawing which shows the example of the experimental result of the pulse reflection method in the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the blade-tip position measuring apparatus in the 2nd Embodiment of this invention. It is explanatory drawing which shows the example of the experiment result of the permeation | transmission method in the 2nd Embodiment of this invention.

<1. First Embodiment>
A first embodiment of the present invention (hereinafter referred to as “this example”) will be described below with reference to FIGS. 1 and 2. In this example, the focus type ultrasonic sensor 2b using the pulse reflection method detects the reflected wave of the ultrasonic wave, and is applied to the blade edge position measuring apparatus 1 that measures the position of the blade edge 5 attached to the micro drill 4. An example will be described.

FIG. 1A shows a configuration example of the blade edge position measuring apparatus 1.
The blade edge position measuring apparatus 1 determines whether or not the blade edge 5 has entered the focus from the detection unit 2 to which the focal ultrasonic sensor 2b is attached and the detection result of the detection unit 2, and determines the position where the blade edge 5 has entered. A measuring unit 3 for measuring. The detection unit 2 includes a focus type ultrasonic sensor 2b that emits ultrasonic waves, and an acoustic lens 2a that collects the ultrasonic waves emitted from the focus type ultrasonic sensor 2b at the focal point. A piezoelectric element formed of a piezo element or a polymer resin is incorporated in the focal ultrasonic sensor 2b. The focal-type ultrasonic sensor 2b disposed in a state separated from the blade edge 5 by a predetermined distance is used as an ultrasonic wave source that radiates ultrasonic waves to the blade edge 5 by applying a voltage and collects it at the focal point. The focal ultrasonic sensor 2 b is used as the detection unit 2 that detects the reflected wave of the ultrasonic wave reflected by the blade edge 5.

  The blade edge position measuring device 1 measures the position of the measurement portion by applying ultrasonic waves to the measurement portion (in this example, the blade tip 5 of the micro drill 4) of the measurement object immersed in the liquid, and measures and detects the position of the measurement portion. Use the method. The detection unit 2 detects a reflected wave in which the ultrasonic wave collected at the focal point is reflected by the blade edge 5. Then, the measurement unit 3 measures the position where the cutting edge 5 of the micro drill 4 has entered the focal point based on the change in the amplitude of the reflected wave detected by the detection unit 2.

  As the blade position measurement method, either (1) pulse reflection method or (2) transmission method is used. In both methods, a water immersion method is used in which the position of the blade tip 5 immersed in the liquid is measured. The blade edge position measuring apparatus 1 of this example uses a pulse reflection method, and hereinafter, an operation example of the blade edge position measurement apparatus 1 using the pulse reflection method will be described.

(1) Pulse reflection method FIG. 1B shows an example of amplitudes of ultrasonic waves and reflected waves.
In the pulse reflection method, the ultrasonic wave I radiated from the focal ultrasonic sensor 2b is reflected by the side surface of the blade edge 5, and returns to the focal ultrasonic sensor 2b. This reflected wave is observed as a reflected wave S. The detection unit 2 measures the amplitude h of the reflected wave S, and the measurement unit 3 measures the position of the blade edge 5.

  When the blade edge 5 enters the focal point of the ultrasonic wave projected by the focal ultrasonic sensor 2b, it is assumed that the amplitude of the reflected wave from the micro drill 4 gradually increases. Here, when the acoustic lens 2a is attached to the tip of the detection unit 2 and the frequency of the ultrasonic wave radiated from the focal ultrasonic sensor 2b is 20 MHz, the ultrasonic wave is focused at a diameter of about 0.2 mm. It can be narrowed down to. At this time, the tip diameter of the acoustic lens 2a is 2 mm, and the distance between the side surface of the micro drill 4 and the surface of the acoustic lens 2a is about 1 mm.

FIG. 2 shows an example of an experimental result of the pulse reflection method.
The horizontal axis represents the distance L (mm) at which the blade edge 5 has entered the tip diameter (in the focal point) of the acoustic lens 2a, and the vertical axis represents the amplitude h (mV) of the reflected wave S. Represents the value of.
FIG. 2A shows an example of a measurement result in the case of using a micro drill 4 provided with a cutting edge 5 having a drill diameter of 0.11 mm and a cutting length of 1.8 mm.
FIG. 2B shows an example of a measurement result in the case of using a micro drill 4 provided with a cutting edge 5 having a drill diameter of 0.6 mm and a cutting length of 7 mm.

  As described above, when the focused ultrasonic sensor 2b used as the detection unit 2 receives a reflected wave, the internal piezoelectric element vibrates and excites a voltage. This voltage is measured as the amplitude h of the reflected wave S.

  From FIG. 2, the behavior in which the amplitude h of the reflected wave S increases as the approach distance of the micro drill 4 increases is obtained. However, in the result of FIG. 2A, the amplitude h suddenly decreases from the approach distance of about 2.3 mm past the blade length of the blade edge 5 which is 1.8 mm, and the ultrasonic wave is reflected from the thicker shank. This is because the reflected wave from the blade edge 5 can no longer be observed. Further, the reason why the amplitude of the reflected wave does not increase gently is that the groove of the microdrill 4 has a groove, so that the intensity of the reflected wave is affected by the presence or absence of the groove.

  From the above results, it was found that if the detection unit 2 detects the amplitude of the reflected wave, the measurement unit 3 can measure the position of the blade edge 5. FIG. 2A shows that the position of the cutting edge 5 having a diameter of 0.11 mm could be measured with an ultrasonic sensor having a focal diameter of about 0.2 mm. A focus type ultrasonic sensor currently on the market has a focus diameter of 0.006 mm (frequency: 140 MHz). Inferring from the results of this time, it is considered that measurement can be performed even at the position of the cutting edge 5 having a diameter of about 0.003 mm by using this focal ultrasonic sensor 2b. The thinnest drill currently on the market has a diameter of 0.01 mm.

  According to the blade edge position measuring apparatus 1 according to the first embodiment described above, the position at which the blade edge 5 of the micro drill 4 enters the ultrasonic focus in a state where the detection unit 2 is immersed in water or oil. It can be measured. At this time, since the blade edge position measuring apparatus 1 does not contact the blade edge 5, no pressure is applied to the blade edge 5, and damage to the blade edge 5 can be prevented.

<2. Second Embodiment>
Next, a blade edge position measuring apparatus 10 according to a second embodiment of the present invention will be described with reference to FIGS. 3 and 4. However, in the following description, parts corresponding to those in FIG. 1 already described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 3A shows a configuration example of the blade edge position measuring apparatus 10 using a transmission method.
FIG. 3B shows an example of the amplitude of an ultrasonic wave.
FIG. 3C shows an example of the amplitude of the reflected wave.

  The blade edge position measuring device 10 is arranged in a state in which the blade edge position measuring device 1 is opposed to the focal ultrasonic sensor 2b serving as an ultrasonic source and is separated from the blade edge 5 by a predetermined distance, in addition to the components included in the blade edge position measuring device 1. An ultrasonic sensor 6 is provided. The ultrasonic sensor 6 is used as a second detection unit that detects a transmitted wave of the ultrasonic wave when the ultrasonic wave radiated from the focal ultrasonic sensor 2 b passes through the blade edge 5.

(2) Transmission Method The blade edge position measuring apparatus 10 of this example measures that the blade edge 5 has entered the focal point of the ultrasonic wave using the transmission method. In the transmission method, the ultrasonic wave I transmitted from the focal ultrasonic sensor 2b is received by the ultrasonic sensor 6 attached facing the focal ultrasonic sensor 2b, and the transmitted wave T is observed. Then, the measurement unit 3 measures the position of the blade edge 5 by measuring the amplitude h of the transmitted wave T detected by the ultrasonic sensor 6.

  As the focus type ultrasonic sensor 2b used in the transmission method, the focus type ultrasonic sensor 2b used in the pulse reflection method is used as it is. The distance between the surface of the acoustic lens 2a of the focal ultrasonic sensor 2b and the surface of the ultrasonic sensor 6 is about 3 mm, and the distance between the side surface of the micro drill 4 and the surface of the acoustic lens 2a is about 1 mm. The ultrasonic sensor 6 is a contact type sensor having a flat surface, and has a frequency of 20 MHz and a vibrator diameter of about 3.2 mm.

FIG. 4 shows an example of the experimental result of the transmission method.
The horizontal axis represents the distance L (mm) that the blade edge 5 has entered into the tip diameter of the acoustic lens 2a of the sensor, and the vertical axis is the amplitude h (mV) of the transmitted wave T, which is a value specific to the blade edge position measuring device 10. Represents.
FIG. 4A shows an example of a measurement result in the case of using a micro drill 4 provided with a cutting edge 5 having a drill diameter of 0.1 mm and a blade length of 1 mm.
FIG. 4B shows an example of a measurement result in the case of using a micro drill 4 having a cutting edge 5 having a drill diameter of 0.6 mm and a cutting length of 7 mm.

  As shown in FIGS. 4A and 4B, when the blade edge 5 enters the focal point of the ultrasonic wave projected by the focal ultrasonic sensor 2 b, the ultrasonic wave is reflected on the surface of the microdrill 4. For this reason, it is presumed that the amplitude h of the transmitted wave T reaching the ultrasonic sensor 6 gradually decreases and eventually becomes a constant value.

  In particular, when a micro drill 4 having a drill diameter of 0.6 mm is used, when the micro drill 4 enters the tip diameter (2 mm) of the acoustic lens 2a, the amplitude of the transmitted wave begins to decrease, and the micro drill 4 is moved to the acoustic lens. When it completely entered the diameter of 2a, a behavior in which the amplitude of the transmitted wave became a constant value was obtained. In the case of the micro drill 4 having a drill diameter of 0.1 mm, the blade length is 1 mm, and when the diameter exceeds the cutting edge 5, the thickness becomes thicker, so that the result is up to 1 mm (L is 1.5 mm). However, unlike the pulse reflection method, the transmitted wave detected in the transmission method is hardly affected by the drill groove. For this reason, it has been found that the amplitude of the transmitted wave detected by the ultrasonic sensor 6 smoothly decreases according to the approach distance of the micro drill 4.

  From the above results, it was found that if the ultrasonic sensor 6 detects the amplitude of the transmitted wave, the measuring unit 3 can measure the position of the blade edge 5. The result shown in FIG. 4 shows that the position of the cutting edge 5 having a diameter of 0.1 mm could be measured using the ultrasonic sensor 6 having a focal diameter of about 0.2 mm. Among the ultrasonic sensors currently on the market, there is an ultrasonic sensor with a focal diameter of 0.006 mm (frequency 140 MHz). If this sensor is used, it is considered that the position of the cutting edge 5 having a diameter of about 0.003 mm can be measured based on the result of this time. The thinnest drill currently on the market has a diameter of 0.01 mm.

The blade edge position measuring apparatuses 1 and 10 according to the first and second embodiments described above have the following effects.
(1) The position of the blade edge 5 can be measured without contact.
(2) Since it is non-contact, handling (position measurement of the blade edge 5) is easy.
(3) Ultrasonic waves can be measured even when oil droplets are attached to the blade edge 5.
(4) It is inferred that the micro-drill 4 having a diameter of about 0.003 mm can be measured with ultrasonic waves.
(5) The measurement unit 3 does not require complicated data processing such as image processing.
(6) The position of the blade edge 5 is measured using the acoustic lens 2a and the focal ultrasonic sensor 2b.
(7) Since a complicated mechanism is not required and the constituent members are small, portable and simple cutting edge position measuring devices 1 and 10 can be configured.

  Moreover, since the blade edge | tip position measuring apparatuses 1 and 10 utilize the water immersion method, even if an oil droplet etc. have adhered to the front-end | tip of the microdrill 4, the position of the blade edge | tip 5 can be measured. In addition, the blade edge position measuring apparatus 1 can make a large change in the reflected wave or transmitted wave of the ultrasonic wave by using the focal ultrasonic sensor 2b so that the blade edge 5 enters the focal range.

  In addition, the cutting edge position measuring devices 1 and 10 have an effect of being able to contribute to improvement in processing efficiency and economic efficiency. The first reason is that, in the contact type, the cutting edge 5 is damaged and the drill life is reduced (down to about 80%), but the cutting edge position measuring devices 1 and 10 of this example are non-contact measurement. This is because the drill life does not decrease.

  The second reason is that, since the position of the blade edge 5 is measured in a non-contact manner, the blade edge 5 is erroneously overloaded, and there is no fear of breaking the blade edge 5 or the micro drill 4 itself. The third reason is that if the life of the micro drill 4 is extended, it will lead to improvement in processing efficiency and economic efficiency. In addition, since it is a portable and simple measuring device, there is an effect that it can be used with various existing machine tools.

  In addition, although the blade edge position measuring apparatuses 1 and 10 which concern on embodiment mentioned above were used in order to measure the position of the blade edge 5, the position of the fine object and micro tool (end mill etc.) which are used for other industrial machines May be used to measure. Moreover, since the non-contact measuring method is used, it can be applied when measuring the position of the rotating tool or detecting the edge state such as damage to the edge 5. Further, the position of the micro tool or the like can be measured not only in water and oil but also in the air. Also, a display unit that displays graphs as shown in FIGS. 2 and 4 is connected to the measurement unit 3, and the operator measures the position of the blade edge 5 while looking at the display unit, and adjusts the entry position of the blade edge 5. You may make it do.

  Further, the present invention is not limited to the above-described embodiments, and it is needless to say that other various application examples and modifications can be taken without departing from the gist of the present invention described in the claims.

  DESCRIPTION OF SYMBOLS 1 ... Cutting edge position measuring apparatus, 2 ... Detection part, 2a ... Acoustic lens, 2b ... Focus type ultrasonic sensor, 3 ... Measuring part, 4 ... Micro drill, 5 ... Cutting edge, 6 ... Ultrasonic sensor, 10 ... Cutting edge position measurement apparatus

Claims (4)

An ultrasonic source that is arranged at a predetermined distance from the measurement site of the measurement object immersed in the liquid, and radiates ultrasonic waves to the measurement site and collects it at the focal point;
A detection unit that detects a reflected wave of the ultrasonic wave that is disposed in a state separated from the measurement site of the measurement target object by a predetermined distance and is reflected by the measurement site located at the focus;
A position measurement device comprising: a measurement unit configured to measure a position where a measurement site of the measurement target object enters the focal point based on a change in amplitude of the reflected wave detected by the detection unit. When the ultrasonic wave emitted from the ultrasonic wave source is transmitted through the measurement site, the ultrasonic wave is disposed in a state of facing the ultrasonic wave source and separated from the measurement site of the measurement target object by a predetermined distance. The position measuring device according to claim 1, further comprising a second detection unit that detects a transmitted wave of the sound wave. The position measurement apparatus according to claim 1, wherein a focus type ultrasonic sensor is used for the ultrasonic source and the detection unit. The ultrasonic wave source disposed at a predetermined distance from the measurement site of the object to be measured immersed in the liquid, and located at the focal point by an ultrasonic source that radiates ultrasonic waves to the measurement site and collects the focal point. Detecting a reflected wave reflected by the measurement site at a predetermined distance away from the measurement site;
Measuring a position where a measurement site of the measurement object enters the focal point based on a change in amplitude of the reflected wave. A position measurement method.

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