JPH01153299A - Detector in water jet machining - Google Patents

Abstract

PURPOSE: To prevent a product from being badly machined to improve its machining quality by comparing a detected value from an acceleration detector provided in a jet receiving means to a reference value, and providing a control means for controlling the movement of a nozzle or an object to be machined in response to the comparison result. CONSTITUTION: When a water jet 10 is spouted from a nozzle 1 to penetrate a work 3 in a state where the nozzle 1 is stopped, and is projected on the water surface of a catcher 5, vibration is produced in water 8 under the water surface by the projection of the water jet. An acceleration detector 6 arranged in the catcher 5 detects the vibration, a signal from the detector is converted into a numerical value and calculated in comparison with a reference value by means of a calculation device 7, and the calculated result is outputted to a control means 9. By command from the control means 9, a nozzle driving means 2 or a work driving means is driven-controlled to move the nozzle 1 or the work 3 to machine the work 3 into a desired shape by means of the water jet 10, and thus to enhance its machining quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a water jet machining device, and more particularly, to a water jet machining device for detecting the jetting state of a water jet when cutting various materials using a water jet. It is installed between the equipment.

[Prior Art] Many technologies that utilize high-pressure fluid jets to process objects have already been put into practical use and effectively utilized. In particular, the heat generation during machining is extremely low, the high-pressure fluid jet that acts as a machining tool has no directionality during machining, the machining allowance is extremely small, the wear of the machining tool is negligible, and machining It has features such as extremely low waste generation, and is used in electronics, machining, medical,
It is widely used in a wide range of fields, including nuclear power.

Looking at machining technology, there are simple ones that move the nozzle manually, automatic dedicated machines that perform routine machining, general-purpose machines that allow free machining, and machining that incorporates manipulators such as robots for three-dimensional machining. It is used in various forms depending on the purpose, such as machines.

Most general-purpose machines have a built-in computer in their control device, store a target machining shape in advance, and move a nozzle or a workpiece according to the memorized machining shape to perform machining.

[Problems to be Solved by the Invention] In such a so-called water jet processing device, the water jet must penetrate the workpiece (hereinafter referred to as the work) from the front surface to the back surface and completely cut the workpiece. However, it has been difficult to mechanically or electrically detect and confirm such water jet penetration. For this reason, water jet machining was performed with specifications that had a margin in advance, resulting in wasted power and machining speed.

A so-called abrasive jet, which is a water jet mixed with an abrasive, is used in a limited number of machining operations, and in such abrasive jet machining, it is extremely important to detect penetration of the jet. Cutting is normally performed automatically by a program, so the time required for penetration is set to a value with sufficient margin based on experience, and the transition from piercing to cutting is made. At this time, if the time required for penetration is too long, the hole diameter will expand at the injection point, which will have a negative effect on the finishing accuracy of the machining. On the other hand, if the distance between the nozzle and the workpiece is too far, or if the supply of abrasive material is insufficient,
In addition, if the cutting ability of the abrasive nozzle has decreased due to its lifespan, etc., the abrasive nozzle may not be able to penetrate within the preset time, and the abrasive material may be scattered around or the subsequent cutting may be incomplete. This makes it impossible to continue machining. Therefore, it is necessary to monitor the time from issuing a jet injection command to detecting penetration, and take measures to continue cutting or issue an abnormal signal to stop automatic operation depending on the time. becomes.

In particular, when cutting a workpiece, an abrasive jet is projected onto a predetermined position of the workpiece, and after the jet passes through the workpiece, the jet or the workpiece is moved to perform the cutting process. At this time, for a short time after the jet is projected onto the workpiece until the jet penetrates the workpiece, the jet and abrasive material will scatter to some extent around the workpiece, but similar scattering may occur due to incomplete machining. This problem also occurs when a portion of the abrasive material is left uncut, and the current situation is that the work environment is worsened by contaminating the surrounding area or damaging unnecessary parts by jets or abrasives.

As a prior art, for limited applications, JP-A-6
There is a technique disclosed in the publication No. 2-199400.

In the prior art, the purpose can be effectively achieved when the nozzle and the workpiece are installed fairly close to each other, but unstable results can be achieved when the nozzle and the workpiece are far apart. I will live.

[Object of the invention] The present invention has been made in view of such prior art,
The object is to provide a device that can effectively detect the penetration of a water jet through a workpiece under any conditions, including when an abrasive is mixed in.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following configuration. In other words, this is so-called water jet processing in which an article is processed with a high-speed jet of water or a high-speed jet of water containing an abrasive, and the high-speed jet of water jetted from a nozzle is projected onto the water surface of a water-filled jet receiving means after processing the article. In the processing device, an acceleration detector attached to the jet receiving means, an arithmetic device that digitizes the signal of the acceleration detector, compares it with a reference value, and outputs the arithmetic result as a signal, and a / and a control means for controlling the movement of the workpiece, and a nozzle drive means for moving the nozzle via the control means based on a signal output from the arithmetic unit, and/and a workpiece for moving the workpiece. The driving means is controlled.

[Effect] Let's talk about the effect. In the following, the term "water jet" refers to both a high-speed water jet and a high-speed water jet containing abrasive material.

In general, in water jet machining, the water jet water stream that contributes to machining has residual force even after penetrating the workpiece, and therefore receives the residual force of the water jet by some means. Such a jet receiving means is commonly called a catcher. There are various types of catchers, such as those that move in synchronization with the nozzle and those that are disposed so as to cover the entire lower part of the workpiece. In the present invention, the catcher is disposed so as to cover the entire lower part of the work, and in order to attenuate the residual force of the water jet, the catcher is filled with water and holds the work at a position a predetermined distance in front of the water surface. The target is a cutting device configured as follows.

In water jet machining, hollowing is often performed at a predetermined position on a workpiece due to the above-described machining features. In such machining, the nozzle is generally stopped during the period from the start of water jet injection to the time when the water jet penetrates the workpiece, except in specific cases. The water jet is sprayed with the nozzle stopped, and before it penetrates the work, the water jet scatters around and does not reach the water surface of the catcher.
It does not have a particularly noticeable effect on water that is filled with water. Next, when the water jet penetrates the workpiece, the water jet is forcefully projected onto the water surface of the catcher due to its retained force. Then, vibrations are generated in the water including the water surface due to the projection of the water jet. . Therefore, if this vibration is detected by an acceleration detector disposed in the catcher and processed by an arithmetic unit, a clear difference between before and after the water jet penetrates the work can be obtained.

The above difference is used to control the drive of the nozzle drive device or the workpiece moving device.

[Example] Hereinafter, the present invention will be described in further detail based on preferred embodiments shown in the drawings.

In the figure, reference numeral 1 denotes a nozzle, which is movably locked by a driving means 2. As shown in FIG. Reference numeral 3 denotes a workpiece, which is held above the water surface of a catcher 5 by holding means 4.

Reference numeral 6 denotes an acceleration detector disposed in the catcher 5 and connected to the arithmetic unit 7. The computing device 7 is connected to a control device 9 that controls movement of the nozzle 1.

In the apparatus configured as described above, first, the water jet 10 is projected onto the workpiece 3 from the nozzle 1 .

Immediately after being projected, the water jet 10 collides with the workpiece 3, bounces off, and scatters around, but after a predetermined time, it penetrates the workpiece 3 and the waterjet 10 uses its remaining force to hit the water 8 spread over the catcher 5. Projected. Since the water jet 10 does not reach the water 8 in the catcher 5 while the water jet 10 has not yet penetrated the work 3, the vibration generated in the water 8 is the vibration generated when the water jet 10 collides with the work 3. These are vibrations propagated from the mechanical drive system. Next, the water jet 10
When the water jet 10 passes through the catcher 5
is projected onto the water 8 , and a shock wave is generated in the water 8 by the projection jet 10 . This shock wave is transmitted to the catcher 5 using water 8 itself as a transmission medium. Then catcher 5
The vibration acceleration and velocity detected by the acceleration detector 6 attached to the machine will show a different value than before.

That is, here, a clear difference can be obtained before and after the water jet 10 penetrates the workpiece 3.

The vibration acceleration detected by the acceleration detector 6 is amplified or filtered to remove noise signals as necessary.
A component that changes before and after the water jet 10 penetrates the workpiece 3 is extracted, and penetration is detected based on whether the component that increases after the penetration exceeds a preset reference value. As another method, it is also possible to detect penetration when the value before penetration exceeds a preset value with respect to the reference value. As for other calculation methods, it is possible to selectively use various methods that are most suitable for use.

Once penetration of the jet 100 is detected in this way, all that is left is to use this detection signal to control the nozzle 1 or/and workpiece 3.
It is used to perform control such as moving or stopping the movement. Whether the nozzle 1 is moved, the workpiece 3 is moved, or both the nozzle 1 and the workpiece 3 are moved depends on the specifications of the cutting system, and each can be used effectively.

It is also possible to use a normal acoustic microphone 62 or an ultrasonic microphone 6'' instead of the acceleration detector 6, but they are easily affected by surrounding noise, making accurate control difficult, and as a result, cutting accuracy may be reduced. It is difficult to recommend this method as it will lead to a decrease in product quality and defective products.

[Effects of the Invention 1] As detailed above, the present invention provides water jet processing for processing articles with a high-speed jet of water or a high-speed jet of water containing an abrasive, in which the high-speed jet of water jetted from a nozzle is used to process an article after processing the article. A processing device configured to project water onto the water surface of a jet receiving means filled with water, a calculation device that digitizes the signal from the acceleration detector, compares it with a reference value, and outputs the calculation result as a signal, and a nozzle. and/or a nozzle drive means that controls the movement of the nozzle via the control means based on a signal output from the arithmetic unit, and/or Since the workpiece driving means that controls the movement of the workpiece is controlled, it is possible to automatically detect whether or not the water jet has penetrated the workpiece, and based on the detection signal, the nozzle Or/and by controlling the movement of the workpiece, it has become possible to prevent product processing defects, and is extremely useful as it can contribute to improving processing quality in the processing concerned. It is.

[Brief explanation of the drawing]

Fig. 1 is a vertical perspective view showing a preferred embodiment of the present invention;
Figure 3 shows an example of the output waveform of a detection signal, Figure 3 shows an example of signal processing, Figure 4 shows an example of using a microphone or an ultrasonic microphone instead of an acceleration detector, and Figure 5 shows an example of using a microphone or an ultrasonic microphone instead of an acceleration detector. The figure shows a conventionally known detection means. 1: Nozzle 2: Driving means 3: Workpiece 4: Supporting means 5: Chatcher 6: Acceleration detector 7 Two calculation devices 8: Water 9: Control device 10: Water jet patent applicant Sugitsu Machine Co., Ltd. Figure 1 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) So-called water jet processing in which an article is processed with a high-speed jet of water or a high-speed jet of water containing an abrasive, in which the high-speed jet of water jetted from a nozzle is projected onto the water surface of a water-filled jet receiving means after processing the article. In the processing apparatus, an acceleration detector attached to the jet receiving means;
It consists of a calculation device that digitizes the signal of the acceleration detector, performs a calculation to compare it with a reference value, and outputs the calculation result as a signal, and a control device that controls the movement of the nozzle and/or the movement of the workpiece. A detection device for water jet machining, characterized in that a nozzle drive means for moving the nozzle and/or a workpiece drive means for moving a workpiece are controlled via the control means based on an output signal. .