JPS6071147A - Profile control device - Google Patents

Abstract

PURPOSE:To prevent a cutter from thrusting into a workpiece at an abrupt change point in the shape of a model without the model being damaged, by detecting an abrupt point in the model shape before a stylus reaches the abrupt point, so that the control of deceleration is carried out. CONSTITUTION:Light from a spot light source 13 impinges upon a light receiving element 18 through lenses 14, 15 and a half mirror 16 and as well so that the light receiving element 19 through a half-mirror 17 so that the light receiving elements 18, 19 issue signals (a, b). A differential amplifier 20 computes the difference between the signals (a, b), and delivers the value of the difference to a speed signal generator circuit 21. A speed control unit 22 drives a motor 24 at a speed corresponding to a signal from the circuit 21 to move the lens 15 to a position where the signals (a, b) are made equal together. A processing device 26 detects the position of the lens 15 at predetermined time intervals by means of a positional detector 25 to calculate the moving amount of a lens 15. If the moving amount is larger than a predetermined moving amount so that there is judged an abrupt change point in a model, a profile control section 10 issues a decelerating signal (d), and after machining at a decelerated speed, the processing device 26 removes the signal (d).

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement in a copying control device, and more particularly to a copying control device that can prevent a cutter from biting into a workpiece at a sudden change point in a model shape. It is something.

Prior Art and Problems A tracing control device moves a tracer head and a cutter integrally based on a displacement signal corresponding to the displacement of a stylus output from a tracer head that tracks a model surface.
It processes the workpiece into the same shape as the model,
If the sudden change point of the model shape is traced at the same speed as other parts, the cutter may bite into the workpiece at the sudden change point, and the machining expansion and softening of the workpiece may not be the same as the model.

Conventionally, in order to eliminate this problem, for example, a potential wire is pasted just before a sudden change point in the model shape, and when the stylus comes into contact with the potential wire, the tracing speed is slowed down to prevent cutter biting. Although efforts have been made to prevent this, there are the following drawbacks. In other words, since it is necessary to attach potential wires to the model, there is a risk of damaging the model, and due to the thickness of the potential wires, the processed shape of the part to which the potential wires are attached may differ from the shape of the model. There was a drawback.

Additionally, a method has been proposed in which a sudden change point in the model shape is detected based on the amount of change per unit time in the displacement signal or composite displacement signal output from the tracer head, and the tracing speed is reduced at the sudden change point in the model shape. However, this method cannot detect the sudden turning point of the model shape until after the stylus reaches the sudden turning point of the model. It was difficult to prevent this from happening.

OBJECTS OF THE INVENTION The present invention has been made to improve the above-mentioned drawbacks, and its purpose is to prevent the cutter from biting in at sudden points of change in the model shape without damaging the model. Examples will be described in detail below.

Embodiment of the Invention FIG. 1 is a block diagram of an embodiment of the present invention, in which 1 is a tracer head, 2 is a squill, 3 is a model, 4 is an X table, 5 is a Z table, 6 and 7 are X, respectively. Motors 8 and 9 for moving Z tables 4 and 5 are X, respectively.
Position detectors for Z tables 4 and 5; 10 is a copying control unit; 1
1.12 is an amplifier, 13 is a spot light source, 14.15 is a lens, 16 is a half mirror, 117 is a mirror, 18.1
9 is a light receiving element, 20 is a differential amplifier, 21 is a speed signal generation circuit, 22 is a speed control unit, 2 is a lens support unit that supports the lens 15, 24 is a motor that moves the lens support unit in two axial directions, 25 is a position detector for the lens 15;
6, a device tracing control section 10 composed of a microcomputer, etc. receives a displacement signal ε8.6 from the tracer head 1 that tracks the model surface. The scanning direction and scanning speed are calculated based on εy and ε2, and the motor 6.
7, and its configuration and operation are already well known.

The light emitted from the spot light source 13 is focused by the lens 14 to form a spot on the model 3. Here, the positional relationship between the tracer head 1 and the spot light source 13 is always kept constant, so that a spot is formed on the processing path. and model 3
The reflected light from the spot is reflected by lens 15 and half mirror 1.
6 to the light receiving element 18, and the lens 1
5. Light receiving element 1 via half mirror 16 and mirror 17
9 and the light receiving element 18 . 19 output signals a and b corresponding to the amount of incident light, respectively. Here, the optical path from the lens 15 to the light receiving element l8 and the lens 15
The optical path difference between the optical path and the light receiving element I9 is ΔL.
Therefore, depending on the position of the lens 15, the light receiving element 18. The output signals a and b of 19 are shown as curves a and b in FIG. 2, respectively. The differential amplifier 2o includes a light receiving element 18. 19, the difference between the output signals a and b is ΔA=a−b,
This is applied to the speed signal generation circuit 21. As shown in FIG. 3, the speed signal generation circuit 21 outputs a speed signal C corresponding to the ΔA. For example, when the difference ΔA is zero, the output signal C is zero, and when the difference ΔA is ΔA1, the output signal C is zero. Outputs speed signal -01, and if difference ΔA is -ΔA1, outputs speed signal C
It outputs 1.

The speed control unit 22 drives the motor 24 at a speed corresponding to the speed signal C from the speed signal generation circuit 21. Therefore, if the difference ΔA is positive, the lens 14 is moved in one Z-axis direction, and if the difference ΔA is negative, the lens 15 is moved in the +Z-axis direction, and the light receiving elements 18 . The lens 15 is moved to a position (point P shown in FIG. 2) where the output signals a and b of the lens 19 are equal. Here, signal a.

The distance D between the model 3 and the lens 15 when the levels of b are equal is calculated by the following formula, where F is the focal length of the lens 15 and E is the image distance when the light receiving element 19 is in focus. ) (1) In this way, the distance between the lens 15 and the model 3 is calculated using the formula (
Since the values are constant as shown in 1), when the shape of the model changes, the two coordinates of the lens 15 also change accordingly. The processing device 26 processes the lens 15 at regular intervals.
Read the detection result of the position detector 25 that detects the position of
Based on the reading result, the amount of movement of the lens 15 per unit time is determined, and if the amount of movement per unit time is more than a predetermined amount, it is determined that there is a sudden change point in the model shape, and the copying control unit 10
A deceleration signal d is sent to the The copying control unit 10 receives a deceleration signal d
From the point in time when machining has been carried out for a predetermined distance L1 from the position of the X table 4 at the time of receiving the data, the sudden change point of the model is moved a predetermined distance Ml [
, z, and then sends a deceleration release signal e to the processing device 26. When the processing device 26 receives the deceleration release signal e, it cancels the deceleration signal d. When the deceleration signal d is released, the copying control unit 10 continues machining at the original copying speed. It is to be noted that whether or not the copying process has been performed for a predetermined distance is determined based on the detection results of the position detectors 8 and 9.

DETAILED DESCRIPTION OF THE INVENTION As described above, one aspect of the present invention is to provide a first lens which receives reflected light from a model and has different optical path lengths from a lens movable in the Z-axis direction. A second light-receiving element (light-receiving element 1B, i9 in the embodiment), a moving means for moving the lens in two axial directions (consisting of a lens supporter and a motor 24 in the embodiment), and a second light-receiving element (light-receiving element 1B, i9 in the embodiment) 1. Control means for controlling the moving means so that the output signals of the second light-receiving elements become equal (in the embodiment, a differential amplifier amplifier, a speed signal generation circuit 21,
speed control unit 22), and position detection means (position detector 25 in the embodiment) for detecting the position of the lens.
), a determining means (processing device 26 in the embodiment) for determining whether or not there is a sudden turning point in the shape of the model based on the detection result of the position detecting means; When it is determined that
In the embodiment, it is equipped with a processing bag W26), and it is possible to reliably detect a change point in the model shape before the stylus reaches a sudden change point and perform deceleration control. This has the advantage of improving processing accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a diagram showing the relationship between the position of the lens 15 and the output signals a and b of the light receiving elements 18 and 19, and Fig. 3 is a speed signal generation circuit. 21 is a characteristic diagram showing the input/output characteristics of No. 21. l is the tracer head, 2 is the stylus, 3 is the model, 4
and X table, 5 is X table, 6.7 is motor, 8,
9 is a position detector, 1o is a scanning control unit, 11.12 is an amplifier, 13 is a spot light source, 14.15 is a lens, 16 is a half mirror, 117 is a mirror, 18.19 is a light receiving element,
20 is a differential amplifier, 21 is a speed signal generation circuit, 22 is a speed control unit, 23 is a lens supporter, U is a motor that moves the lens supporter 23 in the Z-axis direction, and 25 is a lens 1
5 is a position detector, and 26 is a processing device. Patent applicant Fanasoku Co., Ltd. Representative patent attorney Gobe Tamamushi (2 others) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a tracing control device that calculates a tracing speed and a tracing direction based on an output signal of a tracer head that tracks the model surface, and moves the tracer head and the model relatively based on the calculation results, a spot light source that creates a spot at a position a certain distance away from the tracer head; a lens through which the reflected light from the spot on the model enters; and the reflected light from the spot on the model enters through the lens. The first lens has a different optical path length from the lens. a second light receiving element; a moving means for moving the lens in the Z-axis direction; a control means for controlling the moving means so that the levels of output signals of the first and second light receiving elements are equal; a position detecting means for detecting the position of the model; a determining means for determining whether or not there is a sudden change in the shape of the model based on whether the detection result of the position detecting means has suddenly changed; A copying control device comprising: a deceleration means for decelerating a copying speed when it is determined that the copying speed is reduced.