JPS63139643A - Rotary body copying method - Google Patents

Abstract

PURPOSE:To enable improvement of machining efficiency, by constructing such that the angular rotary speed of a model can be varied according to the distance between the center of rotation of the model and the center of stylus, thereby machining with constant cutting face speed at all times. CONSTITUTION:A controller CPU reads out current position in the direction of Z-axis from a current position counter CZ for every sampling time DELTAT and operates the displacement DELTAZ in the direction of Z-axis of a stylus ST, then operates the current value L of R0 based on the radius S of the stylus St being inputted from a keyboard KB and set into a memory MEM and the distance R0 between the lowermost point of the stylus ST under initial state and the center of rotation of a model MDL. Then the speed VX in the direction of X-axis is read out from a distribution circuit DC and employed together with the distance L for obtaining the angular rotary speed W of the model MDL which is outputted subsequently. DA converters DA1, DA2 input a speed component VZ and an angular speed W to drive circuits DRZ, DRQ so as to rotate motors MZ, MQ thus rotating the model MDL through a belt B, while simultaneously move the stylus St in Z-direction thus carrying out machining by means of a cutter CT.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for tracing a rotating body, and in particular, the rotational angular velocity of a model, which is a rotating body, is determined according to the distance between the center of a stylus that contacts the model and the center of rotation of the model. This invention relates to a method for tracing a rotating body that is variably controlled.

<Prior art> In the profiling control, the surface profiling method moves the stylus ST in the direction of the X axis, which is the feed axis, within the range of X, ~x2, which is the feed axis, and the shape of the model MDL. The stylus is moved up and down in the Z-axis direction, which is the tracing axis, according to the shape of the model MDL, and the model MDL is then curved using a stylus to process the work according to the model shape using a cutter (not shown). In this surface tracing method, only the model shape above the feed axis (X-axis) can be traced.

By the way, when patterning a cam or a golf club head, it is necessary to pattern both the front and back sides, not just one side. In order to apply the above-mentioned surface tracing method to such both the front and back sides, the stylus ST must be rotated 180 degrees when transitioning from front side tracing to back side tracing as shown in Figure 4 (see dotted line in Figure 4). . However, a configuration in which tracing is performed by rotating the stylus 180 degrees is complicated and undesirable.

Therefore, a rotating body tracing method that does not require rotating the squill has been proposed and put into practical use.

This method of tracing a rotating body is based on the model M as shown in Figure 5.
While rotating the DL around a predetermined rotation axis, the stylus ST, which is in contact with the model, is rotated at the center 06 of the stylus.
The control is performed by moving the model forward and backward in the direction connecting the rotation center O1 and the rotation center O1 (Z-axis direction) according to the shape of the model.

<Problems to be Solved by the Invention> However, in the conventional rotating body model, the model MDL was rotated at a constant angular velocity.

For this reason, the relative speed between the stylus and model changes depending on the distance between the center of rotation of the model and the point of contact with the model of the stylus, and the relative speed (cutting speed) between the cutter and workpiece changes. It is necessary to determine the angular velocity so that the cutting speed (maximum cutting speed) at the point where it is maximum does not exceed a permissible value, and for this reason, there has been a problem that the angular velocity cannot be set high, resulting in low machining efficiency.

From the foregoing, it is an object of the present invention to provide a rotating body tracing method that can variably control the angular velocity of a model, in other words, the cutting speed, and improve machining efficiency.

Means to solve problems〉 FIG. 1 is a schematic explanatory diagram of the method of the present invention.

ST is the stylus, MDL is the model, 09 is the center of the stylus, OL, l is the center of rotation of the model, S is the radius of the stylus, R is the lowest point of the stylus and the center of model rotation Of
, the distance between L is 0SOr, 1!1 distance.

Action> While rotating the model MDL, the stylus ST in contact with the model is aligned between the center 06 of the stylus and the center of rotation O.
The rotating body is traced by moving it up and down in accordance with the model shape in the Z-axis direction (vertical direction), which is the direction connecting the points 1 and 1.

That is, the velocity component v2. in the Z-axis direction and the X-axis direction (horizontal direction) orthogonal to the Z-axis is calculated using the three-dimensional displacement of the squirrel ST. vx is calculated using the same method as in the well-known surface tracing method. Then, the distance between the center OS of the stylus and the rotation center O,,1 of the model is monitored, the rotational angular velocity W of the model is determined using the distance and the horizontal velocity component vx, and the rotational angular velocity W of the model is determined by the velocity component Vz. , rotate the model MDL at the obtained angular velocity W, and perform tracing control (a!It!!).

<Example> FIG. 1 is a schematic explanatory diagram of the method of the present invention, in which (A) shows the initial state and (B) shows the state after the model has been rotated by 90 degrees.

ST is stylus % MDL is model, 0. is the center of the stylus, 0. , l is the center of rotation of the model, S is the radius of the stylus, R is the distance between the lowest point of the stylus and the center of rotation of the model, and L is the distance between OsO□.

Note that the direction connecting the center point OS of the stylus and the rotation center O of the model is the Z-axis direction (vertical direction), and the direction orthogonal to the Z-axis is the X-axis direction (horizontal direction).

The model MDL rotates clockwise (Q-axis direction) around the rotation center O0, and the stylus ST that contacts the model MDL moves up and down in the Z-axis direction according to the model shape.

FIG. 2 is a block diagram of a device implementing the invention.

DG is a displacement synthesis circuit, CC is a switching circuit, IND is an indexing circuit, ARN, ART are speed calculation circuits, ADDI is an addition type, DC is a distribution circuit, DAI, DA2 are DA converters, cp
u is a computer-configured control device, MEM is a memory, and K
B is the keyboard, MZ, MQ are the Z axis and rotation axis Q
The axis servo motors, DRZ and DRQ, drive the Z-axis and Q-axis servo motors W! A control circuit, PZ and PQ are position detectors, CZ and CQ are up/grand counters (current position counters) that memorize the current position, TR is a tracer head, ST is a stylus, CT is a cutter, B is a belt, and W is a Work and MDL are models.

It should be noted that the tracer head TR and the force/contact CT move together in the Z direction, and the model MDL and the workpiece W rotate in the same direction via a belt.

The method of the present invention will be explained below with reference to FIGS. 1 and 2.

In advance, the radius S of the stylus ST from the keyboard KB,
The distance @Ro between the lowest point of the stylus and the model rotation center 06 in the initial state (see FIG. 1(A)) is input and set in the memory MEM.

In this state, the model MDL is positioned at the initial state position, and then the rotating body tracing is started and the stylus ST is brought into contact with the model by an approach operation (see FIG. 1(A)).

When the approach ends with the squirrel ST coming into contact with the model MDL, the following rotating body tracing according to the present invention begins.

The tracer head TR generates a displacement signal CX corresponding to the three-dimensional displacement of the stylus ST moving in contact with the model MDL;
ε7. C2, and the displacement synthesis circuit DG outputs a displacement signal ε
8. ε7. A composite displacement signal ε=r is created from ε2 and added to the adder ADD1, and the adder ADDI calculates the difference between the composite displacement signal ε and the reference displacement signal C0 and sends it to the speed calculation circuit ARN.

In addition to ART, speed calculation circuits ARN and ART obtain a normal direction speed signal V 1 and a tangential direction speed signal vT, respectively, and apply them to the distribution circuit DC. Further, the switching circuit CC receives the displacement signal ε8. Add ε2 to the indexing circuit IND, and the indexing circuit I
ND is the displacement signal ε8. Displacement direction signal si based on ε2
Create nα, QO8Q and add it to the distribution circuit DC. The distribution circuit DC receives displacement direction signals sina, cosa
, the command speed signals v<, vz in the X-axis and Z-axis directions are created from the normal speed signal v7 and the tangential speed signal v7.

The above is exactly the same as surface profiling control in the orthogonal coordinate system and is well known.

On the other hand, the control device cpu calculates the current position 2 of the two axes from the current position counter CZ at every predetermined sampling time ΔT. At the same time, from z -2 → ΔZ, the Z-axis direction movement amount ΔZ during one sampling time ΔT is determined (z is the current position at the time before ΔT), and from ΔZ+ΔZ → Δ2, the initial position (first Figure (B) dotted line) and current position @(
The Z-axis direction displacement amount ΔZ of the stylus center 09 in FIG. 1 (B) solid line) is calculated.

Next, the control device CPU calculates the distance between the center Os of the stylus ST and the rotation centers 0 and 1 of the model using the following formula %.

After that, the control device CPU reads the X-axis direction velocity vx from the distribution circuit DC, and uses the determined distance and velocity component vX.
The rotational angular velocity W of the model according to the horizontal velocity vx is calculated using
is calculated using the following formula % formula % and output.

DA converters DAI and DA2 each have Z-axis velocity component v2
, Converts the angular velocity W into an analog speed command voltage and inputs it to the drive circuits DRZ, DRQ, and connects the corresponding servo motor MZ,
Rotate MQ. As a result, the model MDL rotates and the stylus ST moves in the Z direction. Similarly, the workpiece W rotates together with the model and the cutter CT moves together with the stylus, so that the workpiece is machined according to the model shape. Ru. Thereafter, the above operation is repeated based on the new displacement 1.

<Effects of the Invention> According to the present invention, the rotational angular velocity of the model is variably controlled in accordance with the distance between the model rotational center point and the stylus center point, so that the cutting speed can be maintained at a constant cutting surface speed at all times. It can be processed and the processing efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the method of the present invention, FIG. 2 is a block diagram of an apparatus for realizing the present invention, and FIGS. 3 to 5 are diagrams explanatory of the conventional method. ST...Stylus, MDL...Model, 0...Center of stylus, 0,...Rotation center of model, S...Stylus radius, L...0.0, distance between Patent applicant FANUC Corporation 1st
Diagram (A)
(B) MOL Motel ζ5

Claims (1)

[Scope of Claims] A method for tracing a rotating body in which a model is rotated and a stylus in contact with the model is moved forward and backward in the direction of the rotation center according to the shape of the model to perform tracing control, which connects the stylus center and the rotation center. Velocity components V_z, V_ in a first direction and a second direction perpendicular to the first direction
x using the three-dimensional displacement of the stylus, monitor the distance L between the center of the stylus and the rotation center of the model, and calculate the rotation of the model using the distance L and the velocity component V_x in the second direction. A method for tracing a rotating body, comprising determining an angular velocity, moving a stylus in a first direction using a velocity component V_z, and rotating a model at the determined angular velocity to perform tracing control.