JPH0691599A - Ultrasonic wave microscopic diameter drilling system - Google Patents

Abstract

PURPOSE:To automate microscopic drilling of a fine ceramics or the like by connecting an ultrasonic wave piezoelectric transducer unit to a 'Z' axial table by means of oscillating mechanisms, providing a microscopic processing pressure responding mechanism and a position sensor on the 'Z' axial table and conducting an NC control of the 'Z' axial table and the microscopic processing pressure responding mechanism. CONSTITUTION:An ultrasonic wave piezoelectric transducer unit 6 equipped with an ultrasonic wave tool on its tip and a 'Z' axial table 8 capable of being NC controlled are connected together with oscillating mechanisms 7, 7'. A cylinder member 9, which is capable of conducting NC control of a microscopic processing pressure responding mechanism energizing specified pressure to the ultrasonic wave piezoelectric transducer unit 6 downward in the axial direction, is arranged on the 'Z' axial table 8. Variation quantity detecting sensor 12 for the relative position in the axial direction of the 'Z' axial table 8 and the ultrasonic wave oscillating unit 6 is provided on the 'Z' axial table 8. An NC controller 13 then controls the 'Z' axial table 8 in accordance with the information from the cylinder member 9 and the position sensor 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention enables extremely small diameter drilling by detecting and adjusting a minute machining pressure and controlling the feeding operation of an ultrasonic tool by NC control in an ultrasonic machine. Processing system.

[0002]

2. Description of the Related Art In recent years, small-diameter holes for fine-cutting materials such as fine ceramics, fine glass, and fine carbon
An ultrasonic processing machine is mainly used for processing irregular-shaped holes and the like. As is well known, ultrasonic machining is a technique in which ultrasonic vibration generated from an ultrasonic tool is applied to free abrasive grains and the work is crushed by the kinetic energy, and there are many parameters in the machining conditions. In order to perform machining as efficiently as possible, it is most important to precisely control the machining pressure generated between the ultrasonic tool end surface and the workpiece machining surface during ultrasonic machining.

Conventionally, there have been the following methods for controlling the processing pressure in an ultrasonic processing machine. (B) The balance mechanism is used to balance the weight of the ultrasonic transducer unit and the processing pressure setting weight, and the processing pressure is set by the weight difference between the ultrasonic transducer unit and the weight. Further, in this case, the Z-axis is not forcibly fed, and the processing speed is set by adjusting the processing pressure. (B) A hydraulic cylinder is incorporated in the processing table, and the processing table detects the processing pressure generated between the tool and the workpiece sent at a constant speed, and operates the hydraulic cylinder to constantly maintain a constant processing pressure. (C) The ultrasonic transducer unit that is slidable in the axial direction is supported from the lower side in the axial direction by a spring, an air cylinder, a hydraulic cylinder, or the like to balance the weight and the supporting force of the ultrasonic transducer unit. Further, a predetermined pressure is applied to the ultrasonic transducer unit from above in the axial direction by a spring, an air cylinder, a hydraulic cylinder, or the like, and this is used as a processing pressure.

[0004]

However, the above (a)-
In any of the methods of (c), there were the following problems. That is, in (a) above, the difference in weight when the vibrator unit and the weight for setting the processing pressure are placed on the balance mechanism is used as the processing pressure, and the processing pressure causes the tool to cut into the workpiece. It was difficult to control the feed amount precisely. For this reason, in order to change the feed rate or detect the buckling load of the tool during machining, it is necessary to rely on the skill of the operator. In each of (b) and (c) above, the vibrator unit is supported by using the sliding member, but this sliding member has its own frictional resistance. Therefore, when machining with a small diameter tool with a small buckling load, the frictional force of the sliding surface becomes larger than the machining pressure and the machining pressure cannot be controlled. It was very difficult.

That is, it is not easy to detect the minute machining pressure and automatically control the precise adjustment of the feed rate according to the magnitude of the machining pressure by any of the above-mentioned prior arts (a) to (c). However, the empirical factor was probably included in the condition setting for optimal processing. Therefore, in the ultrasonic micro-drilling process, the labor cost occupies most of the processing cost, and there is a limit to the reduction of the processing cost. Also,
It is important to detect the amount of tool wear in ultrasonic machining, but this amount of tool wear is not only subtle due to changes in machining conditions such as the supply state of abrasive grains and the tool feed rate, as well as the material of the workpiece and tool. The tool does not always wear at a constant rate because it changes. And, the smaller the diameter of the tool, the more easily it is affected. Therefore, when it is necessary to control the machining depth, such as for spot facing machining, or when multiple holes are continuously drilled by automatic operation, predict the tool wear amount according to the machining amount in advance. Although the machining is performed in advance, when the tool wear amount deviates from the expected value, the machining depth becomes too deep or too shallow, resulting in machining failure. Further, when processing through-holes, the cutting amount of the tool is made larger than the thickness of the work, and a method of co-cutting the base material to which the work is pasted is taken, but usually, in order to prevent the occurrence of non-through holes, The depth of co-machining is set to be large in consideration of the amount of tool wear. Therefore, when setting the depth for co-machining, it was not possible to easily grasp the tool wear amount accurately, so the safety factor had to be increased, and the machining efficiency was reduced accordingly. The present invention has been made in order to solve the above problems, and performs high-precision setting and detection of a minute processing pressure, which has been difficult with a conventional ultrasonic processing machine, by NC control. It is an object of the present invention to provide an ultra-small diameter drilling system for an ultrasonic processing machine that can realize automation of ultra-small diameter drilling by controlling the operation of a table.

[0006]

In order to achieve the above-mentioned object, the present invention comprises the following technical means.
(A) An ultrasonic transducer unit having an ultrasonic tool at its tip and an NC controllable Z-axis table are connected via a swing mechanism. This swing mechanism balances the own weight of the ultrasonic transducer unit and allows the ultrasonic transducer unit to be displaced in the axial direction. (B) On the Z-axis table, an NC-controllable cylinder member is arranged as a mechanism for dealing with a minute machining pressure that urges a predetermined pressure axially downward with respect to the ultrasonic transducer unit. (C) A position sensor for detecting the amount of change in the relative position of the Z table and the ultrasonic transducer unit in the axial direction is arranged on the Z axis table or the ultrasonic transducer unit. (D) The mechanism corresponding to the minute processing pressure and the position sensor are connected to the NC controller, and the NC controller performs centralized control together with the operation of the Z-axis table.

[0007]

According to the above means, since the Z-axis table and the ultrasonic transducer unit are connected via the swing mechanism,
If the weight of the ultrasonic transducer unit and the supporting force of the swing mechanism are balanced, the force exerted by the tip of the ultrasonic tool on the work surface is apparently zero. The pressure applied axially downward to the ultrasonic transducer unit by the processing pressure corresponding mechanism acts as a force corresponding to the processing pressure. That is, since the oscillating mechanism cancels the self-weight of the vibrator unit, the processing pressure generated between the ultrasonic tool and the workpiece is just balanced with the pressure urged by the processing pressure corresponding mechanism. Further, the position sensor arranged on the Z-axis table or on the ultrasonic transducer unit can detect a slight change in the relative position between the Z-axis table and the ultrasonic transducer unit.

When ultrasonic processing is performed by setting a predetermined processing pressure by the above mechanism, the following operation is performed when a slight overload occurs. That is, when an arbitrary processing pressure P is set by the processing pressure corresponding mechanism and the Z axis is fed at an arbitrary feed speed V1, a state where V1> V2 with respect to the actual processing speed V2 determined by the processing pressure P is obtained. When this happens, the tool is not cut further and the ultrasonic transducer unit tries to stop the displacement with respect to the work. However, in this case as well, Z
Since the axis table continues to feed as it is, the relative position of the ultrasonic transducer unit and the Z axis table tries to change, and the compressive force is applied to the processing pressure corresponding mechanism placed between the Z axis table and the ultrasonic transducer unit. Working. Then, when a compressive force above the set pressure is applied, an overload condition occurs and the relative position between the ultrasonic transducer unit and the Z-axis table begins to change, and at the same time, the position sensor detects the amount of change in the relative position. Since an alarm signal is output as a result, if the Z-axis operation is controlled using the signal, it is possible to quickly get out of the overload state.

Further, by detecting the minute pressure applied to the tool by the above mechanism and controlling the operation of the Z axis, the amount of tool wear of the extremely small diameter tool can be detected. That is,
Before starting drilling, the Z-axis is lowered at a low speed with the ultrasonic device stopped, and the Z-axis is stopped at the point where the tip of the tool hits the work surface and an alarm signal is sent from the position sensor. Read H1. Next, after driving the ultrasonic device to perform predetermined drilling, the ultrasonic device is stopped, the Z axis is once returned to the origin, and the Z axis is lowered again at a low speed, so that the tool tip is on the work surface. The Z axis is stopped at the hit point and the coordinate H2 at that time is read. Then, the coordinate H2 is compared with the coordinate H1 read before processing, and the difference H1-
H2 is detected as the tool wear amount H3, and when machining the next hole, the tool feed amount is set by adding the tool wear amount H3 as a correction amount to the machining depth D. If this operation is performed every time one hole is drilled or every time a fixed number of holes are drilled, the tool wear amount that is always determined by the machining conditions at that time can be detected, so that more accurate machining depth can be managed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram of an ultrasonic ultra-small diameter drilling system of the present invention. The ultrasonic oscillator 1, the cone 2, the horn 3, and the tool 4 are coaxially connected to each other, and further, the one in which the flange portion of the cone is fixed to the pedestal metal fitting 5 is an ultrasonic oscillator unit 6, which is composed of upper and lower two sheets. It was attached to the Z-axis table 8 by using leaf springs 7 and 7 ′ so that the ultrasonic transducer unit 6 can swing with respect to the Z-axis table 8. In addition, a coupler 10 is attached to the tip of the electric cylinder 9, and a spring 11 is further connected to the tip of the coupler to form a mechanism corresponding to machining pressure. The electric cylinder 9 is placed on the ultrasonic transducer unit 6 side, and the tip of the spring 11 is attached. It was fixed to the Z-axis table 8. That is, by adjusting the stroke of the electric cylinder 9, the total length of the spring 11, that is, the force applied to the spring 11 can be adjusted, and this force acts as a force that opposes the working pressure. Further, a position sensor 12 for detecting the amount of change in the relative position with respect to the Z-axis table 8 is provided on the ultrasonic transducer unit 6.
Was placed. The electric cylinder 9 and the position sensor 12 are connected to the NC controller 13 of the Z-axis table 8,
It can be linked with the axis table 8.

In this embodiment, the program is made so that the operation of the Z-axis table 8 can be controlled as described below. (B) Z-axis feed rate control during machining Machining is started at an arbitrary Z-axis feed rate v1 for a fixed time t
If the machining is progressing without sending an alarm signal during the process when the time has elapsed, the NC controller 13 determines that the machining progress is good, and accelerates the Z-axis feed speed from v1 to v2 according to the pre-programmed acceleration rate. . And
If the machining is continued and the machining progresses without sending an alarm signal during the machining, the acceleration operation of the Z-axis feed speed is executed at every constant time. Conversely, any Z
If an alarm signal is transmitted during machining at the axis feed speed v1 ', the Z-axis table 8 is raised by the height h for each transmission up to the arbitrarily set number of transmissions, and the Z-axis table 8 is again moved from that position. The Z-axis table 8 is lowered to continue the machining. After that, when the machining state does not improve and the number of times the alarm signal is transmitted exceeds the set number of transmissions, it is determined that the feed rate is inappropriate, and v1 'to v
Decelerate to 2 '. Then, the deceleration operation is repeated until the Z-axis feed speed reaches an appropriate value. (B) Correction of tool feed amount by detecting tool wear amount Z-axis table 8 with ultrasonic device stopped before machining
Is lowered at a low speed to stop the Z axis at the point where the tip of the tool hits the work surface and an alarm signal is transmitted from the position sensor, and the coordinate H1 at that time is read. Next, after driving the ultrasonic device to perform one hole machining, the ultrasonic device is stopped, the Z axis is once returned to the origin, the Z axis is lowered again at a low speed, and the tool tip hits the work surface. Then, the Z-axis is stopped, the coordinate H2 at that time is read and compared with the coordinate H1 read before machining, and the difference H1-H2 is detected as the tool wear amount H3. Then, when machining the next hole, a distance obtained by adding the tool wear amount H3 as a correction amount to the machining depth D, that is, D + H
Set 3 as the tool feed amount. However, only for the first machining, the estimated amount of tool wear must be used.

Using an ultrasonic processing machine equipped with the above mechanism, ultrasonic processing was applied to Pyrex glass having a thickness of 2 mm. Normally, the frequency is 16 to 30 kHz and the output is 50.
An ultrasonic processing machine of W to 1 kW is used, but in the present embodiment, a frequency of 60 kHz and an output of 10 for fine hole processing.
Using 0W ultrasonic wave, ultrasonic tool has a diameter of 0.1mm,
A stainless steel pin having a tool length of 10 mm was soldered to the tip of the horn, and a through hole having 100 holes was drilled. Further, the processing pressure is set to 80 gf by the processing pressure corresponding mechanism, and the position sensor 12 is set to the ultrasonic transducer unit 6 and Z
The alarm signal is set to be emitted when the amount of change in the relative position to the axis table 8 reaches 10 μm. Further, the Z-axis feed rate at the start of machining is v1 = 2 mm / min, the acceleration rate is 10% when the machining state is good, and the deceleration rate is 1 when the alarm signal is transmitted.
0%, set time t for determining acceleration of Z-axis feed speed
For 15 seconds, the number of alarm signal transmissions for determining the deceleration of the Z-axis feed speed is 5 times, the step amount h of the Z-axis table 8
= 50 μm.

After the start of processing, the processing proceeds without any problems while the ultrasonic wave oscillation state, the abrasive grain circulation state, and the tool feed rate are balanced, and after 30 seconds, the Z-axis feed rate is 2.42 mm. Accelerated to / min. However, once the balance is lost for some reason, the tool 4
No longer cut into the work. Then, the oscillating mechanism of the leaf springs 7 and 7'stops the displacement of the ultrasonic transducer unit 6 in the axial direction, and only the Z-axis table 8 tries to move downward in the axial direction. The machining pressure generated during the time gradually starts to rise, and when the machining pressure becomes larger than 80 gf set by the mechanism corresponding to the machining pressure,
Finally, a relative gap started to be generated between the ultrasonic transducer unit 6 and the Z-axis table 8. Then, when the gap reaches the set value of the position sensor 12 of 10 μm, an alarm signal is issued, whereby the Z-axis table 8 executes the step operation of the step amount h = 50 μm and continues the machining. After that, an alarm condition frequently occurred during machining, but the Z-axis feed speed was 2.42 mm /
The speed was decelerated from min. To 2.2 mm / min. After that, when the machining was continued while repeatedly accelerating and decelerating the Z-axis feed speed similar to the above, one hole could be machined in 2 minutes and 30 seconds without buckling of the tool due to overload. Also,
By detecting the tool wear amount each time one hole was machined and setting the tool feed amount for the next machining, good drilling could be performed on all 100 holes without the generation of unpenetrated holes.

[0014]

As described above, according to the ultrasonic ultra-small diameter drilling system of the present invention, the self-weight of the ultrasonic transducer unit is offset by the supporting force of the swing mechanism, and NC control of 100 gf or less is performed. Precise machining pressure can be set easily and the tool can be fed at the optimum feed rate at all times. Therefore, even a tool with a very small diameter can be machined without damage due to overload. Further, since the tool wear amount can be detected every time one hole is machined and the tool feed amount for the next machining can be set, it is possible to eliminate the variation in the machining depth. Further, the processing system of the present invention can be applied not only to ultrasonic processing but also to electric discharge processing and drilling with a fine drill.

[Brief description of drawings]

FIG. 1 is an explanatory view of an ultrasonic ultra-small diameter hole drilling system of the present invention.

[Explanation of symbols]

1 ... Ultrasonic transducer, 2 ... Cone, 3 ... Horn, 4
… Tools, 5… Pedestal brackets, 6… Ultrasonic transducer unit,
7, 7 '... Leaf spring, 8 ... Z-axis table, 9 ... Electric cylinder, 10 ... Coupler, 11 ... Spring, 12 ...
Position sensor, 13 ... NC controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kinya Miyashita 2-10-15 Honcho, Kawasaki-ku, Kawasaki-shi, Kanagawa Top 5-202 Kawasaki

Claims (1)

[Claims] 1. In an ultrasonic processing machine, (a) an ultrasonic transducer unit having an ultrasonic tool at its tip and an NC-controllable Z-axis table are connected via a swing mechanism. (B) An NC controllable micro-machining pressure corresponding mechanism for urging a predetermined pressure in the axial downward direction with respect to the ultrasonic transducer unit is arranged on the Z-axis table. (C) A position sensor that detects the amount of change in the relative position of the Z-axis table and the ultrasonic transducer unit in the axial direction is arranged on the Z-axis table or on the ultrasonic transducer unit. An ultrasonic ultra-small diameter drilling system characterized by using the ultrasonic processing machine configured as described above.