JPS6219374A - Grinding device - Google Patents

Abstract

PURPOSE:To make high accuracy, high efficiency, automatic grinding of extremely thin work possible by providing a numerical control with additional data on the condition of a work, thereby performing suitable numerical control of relative travels of both the work and a grinding unit. CONSTITUTION:Since a work W recedes against a grindstone 5 when grinding speed in the fore-and-aft direction is too high, the travel of this recession is sensed with an electronic micrometer 13. The detected displacement (recession travel) is inputted via an A/D converter 15 and a data input unit into a data judgment unit. When the inputted data exceeds a preset value, existing speed of the grindstone is reduced by 10% by applying override. Sensing if the input data has come down below the preset value is continued to that the override application for 10% speed reduction is repeated at specified time intervals until the input data comes below the preset value. As a result, high accuracy grinding of the work is possible with the grindstone 5 while controlling the displacement (recession travel) of the work W not to become too great.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a grinding device that enables automatic grinding of thin objects.

[Description of prior art]

A conventional grinding device is one in which either a workpiece or a grinding object such as a grindstone is fixed, and the other is operated under numerical control. Therefore, in general, it is possible to perform desired grinding on a workpiece by appropriate numerical control.

However, when the workpiece is a thin object, such as a mold for molding an IC lead frame (0.1 to 0.2 mm), it is extremely difficult to perform the numerical control appropriately.

This is because when grinding thin materials, the workpiece tends to "run out", and the grinding resistance also causes distortion and bending, so numerical control cannot be done until these phenomena are taken into account. In cases where it is difficult to do so, it is difficult to automate it using numerical control on the bottom side, so it is usually preferable to use an optical copying grinding device, and the actual situation is that manual grinding is performed while observing the actual machining state. It is.

[Purpose of the invention]

In view of the above-mentioned circumstances, it is an object of the present invention to provide a grinding device that enables automatic grinding of ultra-thin objects.

[Summary of the invention]

In order to achieve the above object, the present invention includes a workpiece support part that supports a workpiece, a grinding part that grinds the workpiece, and a state that detects the physical state of the workpiece during processing. Grinding comprising: a detection section; and a numerical control section that numerically controls the relative movement amount between the workpiece and the grinding section within a range in which the state quantity detected by the detection section does not exceed a predetermined state quantity. The apparatus was configured to appropriately numerically control the amount of relative movement between the workpiece and the grinding section by taking into account the state quantity of the workpiece in the numerical control.

[Description of Embodiments] Hereinafter, the present invention will be described in detail using an example in which the present invention is applied to an optical tracing grinding device.

Fig. 1 is an explanatory diagram of the optical tracing grinding device, Fig. 2 is a block diagram of the NC device, Fig. 3 is a 70 chart showing an example of deceleration control, Fig. 4 is a flowchart showing an example of complete feedback control, and Fig. 5 is a diagram showing an example of complete feedback control. The figure is a perspective view showing a reference example of the sensor section, and FIG. 6 is an explanatory diagram showing the state of the sensor output signal controlled based on the control example shown in FIGS. 3 and 4.

As shown in FIG. 1, the optical copy grinding apparatus 1 includes a fixed table 3 that supports a thin workpiece W, a grinding wheel 5 that performs a grinding action on the workpiece W by rotation, and a grinding wheel 5 that performs a grinding action on the workpiece W by rotation. and a projector 7 through which the relative positional relationship between the grinding wheel 5 and the grinding wheel 5 can be observed.

A chart paper indicated by a broken line can be attached to the projector 7, and an enlarged image of the workpiece W and the grinding wheel 5 can be projected as indicated by a solid line. , it is now possible for the operator to observe the machining status I2. Note that as these projection means of this embodiment, conventionally used ones can be used as they are, so detailed explanation thereof will be omitted here.

The grinding wheel 5 is attached to a grinding wheel head 7 via a lifting table 9. The lifting table 9 can be raised and lowered in the vertical direction Z with respect to the grinding wheel head 7, and the grinding wheel head 7 is moved vertically to the plane of the paper in FIG. It is configured to be driven in the horizontal direction by a Y-axis servo motor MY. X-axis servo motor Mx, Y-axis servo motor M
Y is driven and controlled by an NC device 11.

An electronic micrometer 13 is attached to the table 3 to detect the displacement of the workpiece W in the left and right direction using a voltage proportional to the displacement. The output voltage of the electronic micrometer 13 is input to an analog-to-digital converter (hereinafter referred to as A/D converter) 15 via an amplifier 13a, and the displacement data D output from the A/D converter 15 is
It is designed to be taken into the C device 11.

As shown in FIG. 2, the NC device 11 includes a data input section 17 that inputs data D from the A/D converter 15.
, a determination unit 19 that determines the captured data, and a speed change command unit 21 that issues a speed change command according to the determination content of the determination unit 19. The details of the determination by the data determination unit 19 and the command by the speed change command unit 21 will be described in detail with reference to FIGS. 3 and 4.

The NO device @11 shown in this example has an NC program input section 23 and an NG data calculation section 25, like a normal NC device.
, a speed override III setting section 27, a voltage command section 29, and servo amplifiers 31 and 33 for the XY axes.

The NC program input section 23 reads one block of NC programs from, for example, an NC tape, performs a format check, etc., and outputs one block's worth of NC programs to the NG data calculation section 25 in a slightly digested form.

The NO data calculation section 25 is the NG program input section 23.
Input one block of program input from
It calculates data for Y-axis control and outputs predetermined data to the voltage command section so as to drive the XY-axis servo motor at a predetermined speed.

The speed override value setting section 27 sets the speed override value setting section 27 to 10 to 200%.
This sets the speed override value in the range of
Here, it is possible to set a predetermined override value according to a command signal from the speed change command section 21.

FIG. 3 shows an example of deceleration control, that is, control that uses output data D from the electronic micrometer 13 to decelerate the drive speed of the grinding wheel 5 when it is too fast.

Now, in FIG. 1, it is assumed that the grinding wheel 5 is operated only in the front-rear direction (X direction) to perform grinding with a constant depth of cut. Therefore, if the grinding speed in the front-back direction is too fast, the workpiece W is
Therefore, the electronic micrometer 13 detects the cause of the escape, and if the amount of escape is too large, the machining speed is reduced.

Step 301 is the displacement m detected by the electronic micrometer 13 via the A/D converter 15 and the data input section 17.
(Escape group) is input to the data determination unit, and input data D is constantly monitored here.

In step 303, it is determined whether the input data D has exceeded the set value [)0 (see curve C1 in FIG. 6). The set value DO is a value set in advance as a value sufficiently smaller than the permissible displacement value Q max.

If the input data D is less than the set value Dθ, the grinding wheel 5
The longitudinal velocity Vx of is controlled to a value determined by a program input to the NC program input section 23 shown in FIG.

Then, when the value of the input data D exceeds the set value (see curve C1 in FIG. 6), the process moves to step 305, where the current speed is overridden by 10%. This override value is specified from the speed change command section 21 shown in FIG. 2 to the speed override value setting section 27.

Step 307 detects whether or not the input data D has become less than the set value DO, and repeats overriding by 10% at predetermined time intervals until it becomes less than the set value.

Step 309 indicates processing for maintaining the override speed determined in this manner until the next block. In this way, the speed change process is performed by the NC program input section 23.
The reason why each input block is processed is to avoid the influence of speed changes on the work of the next block.

Thus, as shown by the curve CI in FIG. 6, the grinding wheel 5 is controlled to be decelerated to a speed at which the input data D does not exceed a predetermined value [ This makes it possible to perform high-precision grinding while avoiding excessive grinding.

Next, an example of complete feedback control shown in FIG. 4 will be shown.

The complete feedback control referred to here is to control the servo motor MX so that the speed in the longitudinal direction (X direction) shown in the example above is a constant value detected by the electronic micrometer 13.

Step 401 shows the process of setting the constant DO. In this example, this constant DO is set in the data determination section 19 shown in FIG. 2.

On the other hand, step 403 shows the initial speed setting process, and this speed is determined by the NC program input unit 2 shown in FIG.
It may be specified in advance on the program input in step 3. Moreover, this can be done by, for example, programming the grindstone 5 so that the movement in the X direction becomes a uniformly accelerated movement at the initial stage.

Therefore, the grinding wheel 5 moves at a constant acceleration at the start of machining. Then, the electronic micrometer 13 shown enlarged in FIG. 5 detects the amount of displacement of the workpiece W, and this detected value is read into the data determination section 19 in step 405.

As shown by curve C2 in FIG.
The value of increases gradually.

Steps 407, 411, and 415 indicate determination processing by the data determination unit 19. Then, the input data D is compared with the setting data DO, and if the input data D is approximately equal to the setting data DO, the speed is maintained as it is in step 409, and [)
>[)0, decelerate in step 413 and [)<[)0
If so, it is accelerated in step 415. These acceleration and deceleration controls are controlled by, for example, +
This is done by changing the override value of 10% or -10%.

In the complete feedback control shown in FIG. 4, the detected data D is controlled to be equal to the set value DO, as shown by the curve C2 in FIG. In this case, the speed of the grinding wheel 5 in the X-axis direction is not necessarily constant, but it can be said that it is controlled at the maximum speed within a range that does not damage the viscosity of the processed product.

In the embodiment shown above, an example was shown in which the detection signal of the electronic micrometer 13 is used to control the feed speed of the grinding wheel 5 in the X-axis direction. It is also possible to control both.

The electronic micrometer 13 as an example of a sensor shown enlarged in FIG. 5 may be of any type, such as a differential transformer type or a potentiometer type, or may be a strain sensor. In short, the amount of displacement of the workpiece is 0.1
It is sufficient if it can be detected with an accuracy of about 1 μm.

Further, as a device for detecting the physical state quantity of the workpiece, it is also possible to use a temperature sensor, a horn sensor, etc. in addition to a meter that measures the amount of displacement itself.

As the temperature γ sensor, for example, a non-contact infrared sensor is used to detect the temperature of the workpiece and provide it to, for example, an NC device. As shown in FIGS. 3 and 4, the NC device can perform predetermined control within a range in which the temperature of the workpiece W does not exceed a predetermined temperature. Note that it is desirable to detect the hot wire measurement point at the contact point of the workpiece W with the grinding wheel 5 shown in FIG. As a result, it is possible to obtain a maximum feed rate within a range that does not cause distortion due to grinding burn and decrease in material height, and it is possible to shorten the grinding time and perform highly accurate processing.

The horn sensor detects the intensity of ultrasonic waves generated from the workpiece W and provides detection data to the NC device. This allows the NC device to perform the same control as above.

Note that the sensors shown above can be used alone or in combination. That is, for example, the temperature sensor and the displacement ff1l? It is possible to change the set displacement amount depending on the low temperature range by combining it with a sensor, and by setting the set value for both sensors and constantly monitoring both physical quantities, it is possible to change the set displacement amount depending on the low temperature range. It is also possible to control the temperature so that it does not reach this level.

(Effects of the Invention) The grinding device according to the present invention can automatically grind thin objects with high precision and high efficiency.

[Brief explanation of drawings]

The drawings all show examples, and Fig. 1 is an explanatory diagram of the optical scanning grinding device, Fig. 2 is a block diagram of the NC device, Fig. 3 is a flowchart showing an example of deceleration control, and Fig. 4 is a flowchart showing an example of deceleration control.
The figure is a flowchart showing an example of complete feedback control, Figure 5 is a perspective view showing a reference example of the sensor section, and Figure 6 is a sensor output signal controlled based on the control example shown in Figures 3 and 4. It is an explanatory view showing a state. 1... Optical copy grinding device 5... Grinding wheel 11... NC device 13... Electronic micrometer 17... Data input section 19... Data judgment section 21... Speed change command section 27 ...Speed override value setting section Fig. 1 Fig. 2

Claims (3)

[Claims] (1) A workpiece support part that supports a workpiece, a grinding part that grinds the workpiece, a state detection part that detects the physical state of the workpiece during processing, and a state detection part that detects the physical state of the workpiece during processing. A grinding device comprising: a numerical control section that numerically controls a relative movement amount between the workpiece and the grinding section within a range in which the detected state quantity does not exceed a predetermined state quantity. (2) The grinding apparatus according to claim 1, wherein the numerical control section controls the state quantity detected by the state detection section to converge to a predetermined setting amount. (3) The state detection section detects the physical state of the workpiece, such as deflection, distortion, temperature, and generated sound, and the numerical control section detects any one of these physical states.
The grinding apparatus according to claim 1, wherein one or more sets of detected values are input to numerically control the amount of relative movement between the workpiece and the grinding section.