JPS5915782B2 - Tracing control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a tracing control method, and particularly to a tracing control method that can perform tracing faithfully to a model even in areas where the model shape changes suddenly.

In profiling machining, gouges occur when machining workpiece positions that correspond to the corners of the model.

This occurs because the profiling speed, that is, the speed of the stylus, cannot be suddenly reduced in areas where the shape of the model changes suddenly, such as corners, so the cutter that is linked to the stylus travels beyond the amount of the workpiece that should be cut.

Conventional countermeasures against this bite include reducing the maximum speed of tracing, attaching tape to the corners of the model, or providing a conductive layer on the corners of the model to obtain a deceleration signal by contact with the stylus. Such methods have been adopted.

However, with the first method, the processing speed decreases and the IL rate decreases, and with the second method, it is difficult to determine the thickness of the tape, and the tedious work of attaching the tape is required.
In addition, the tape attachment creates a step on the model surface, which is reflected in the processed shape.The third method requires a conductive layer to be provided on the model.The stylus of the tracer head is configured as an electrical contact element. It has disadvantages such as the necessity arises.

The present invention eliminates these drawbacks, and its purpose is to make it possible to trace accurately and faithfully to the model even in areas where the model shape changes suddenly, while reducing processing time and making it easy to handle. The purpose of this invention is to provide a tracing control method.

The details will be explained below based on the embodiments shown in the drawings.

Figure 1 is a perspective view of an example of a model MO that has a part where the shape changes suddenly, and Figure 2 is its plan view.The model MO in Figure 1 is traced along the X-7 plane and picked at the Y-2 plane. When feeding (Y-axis pick feed amount Py) is applied to trace the entire surface of the model, the model shape changes suddenly at positions P1 to Pn.

The tracing path PA in the same figure shows the case of rough machining, and as is clear in Figure 2, the model surface is divided into a plurality of divided regions having an axis of rough machining pink feed amount Py with respect to the pick feed axis (Y axis). DYI.

DY2. ...It can be classified into DYn.

In the present invention, sudden model change positions P1, P2, . . . -jPn are input and stored in correspondence with each of these divided regions.

Model sudden change position P1, P2゜..., Pn//'i
Each position P1. has an X coordinate value X and two coordinate values y, and each position P1. P2.
..., one deceleration region DDI, DD for Pn, respectively.
2~. DDn can be set.

For example, regarding the model sudden change position P1 (x*Z1), the deceleration/region DD1 is determined as a region.

Figure 3 shows the case of finishing machining, and since the pick feed amount ΔP for finishing machining is smaller than the big feed amount Py for rough machining, tracing operations are performed several times in one divided area, for example DYl, but the During the profiling operation in the area DY1, the profiling feed rate is decelerated when the current position of the machine is in the area DD1 shown in equation (1) above.

When the tracing moves to the next divided area, the deceleration area set based on the information stored corresponding to the divided area is compared with the current position of the machine, and the same deceleration control as described above is performed.

FIG. 4 is a block diagram of an embodiment of the present invention.
IND is the displacement signal ε, ε of the output of the tracer head TR
, ε are input to the displacement synthesis circuit X y
z and indexing circuit, ARN, ART are speed calculation circuits, ADD
is an adder circuit, DC is a distribution circuit, GC is a gate circuit, DR
VX, DRVY, DRVZ are amplification output circuits, MX, MY
, MZ is servo motor, PCX.

pcy, pcz are position detectors, MDL is the model, ST is the stylus, CT is the cutter, W is the workpiece, MACH copying ray machining machine X, CTY, CTZ counts the pulses from the position detector to determine the current position. A reversible counter indicating O
PP is the operation panel, BTI, Br3 is the start and stop push button, KB is the keyboard, DSP is the display, Dll
, DI2 is a data input device, MEM is a memory consisting of a data memory section and a control program section M2, and DO
is a data output device, CPU is a processor, and MD is a detection circuit for a sudden change in model shape.

The stylus ST comes into contact with the model MDL and is fed by a servo motor, and displacement signals ε, ε, ε or x y are generated according to the displacement of the stylus ST.
A composite displacement signal ε of z is output, and the indexing circuit IND outputs displacement direction signals sinθ and e08θ.

The composite displacement signal ε is added to an adder circuit ADD to produce a reference displacement signal ε.

The difference Δε between the normal direction velocity signal vN and the tangential direction velocity signal
T is obtained, and in the distribution circuit DC, the displacement signal sinθ
A command speed signal is created based on 5 cos θ and applied to the gate circuit GC.

A command speed signal is applied to the amplification output circuit selected by the gate circuit GC, and the servo motor is driven in accordance with the command speed signal to drive the cutter CT and tracer head TR.
An integrated delivery is carried out.

Since the above-mentioned operation is already known, detailed explanation will be omitted.

In the embodiment of the present invention, the limit coordinate values of the contouring area, the rough skin epic feed amount Py1, the finishing epic feed amount ΔPy1, the deceleration area parameter δ, etc. are entered using the keyboard K.
B, the memory M is input via the data input device D11.
10 is stored in a predetermined area.

First, command the rough machining mode RT from the keyboard KB, press the start button NBT 1 on the operation panel OPP to start rough machining tracing, and move the stylus from point S in Figure 2 to +x.
Suppose that force direction tracing is started.

When the stylus reaches point 21 in FIG. 2, it hits the wall of the model MO, and the displacement of the stylus in the X-axis direction increases rapidly.

As a result, Fig. 4 shows the output D of the detection circuit MD for sudden changes in model shape.
ET becomes "113" and is read by the processor CPU via the data input device DI2.

Processor CPUH Current count CTX, CTZ
These coordinate values (xl s Z 1 ) are stored in a predetermined area of the memory M1 in association with the divided area DY1.

Next, when the limit in the +X direction is reached, the pick feed (pick feed amount Py) is performed in the 10Y direction on the Y-Z plane, and then the pattern shifts to the -X direction, and a sudden change in the model shape occurs again at the 22nd point. , similarly, (X2, z2) is stored in the memory M1 at 1-.

Similarly, the points Pi and P2゜where the model shape suddenly changes
..., the coordinate values of Pn are each divided area DYI, DY2.

...=Memo υM1 as shown in Table 1 corresponding to DYn
is memorized.

Next, for finishing, a finishing mode PT is commanded from the keyboard KB, and a start button BTI on the operation panel OPP is pressed.

It is assumed that the stylus starts tracing in the +X direction from point S in Figure 2.

First, the processor CPU calculates in advance in which divided area the current position y on the Y axis exists.

y1≦y<y1+Py, that is, the coordinate values (x, Z
) and a predetermined region parameter δ to set the deceleration region DD1 expressed by the formula (1) above, and read the counter CTX at regular intervals.

The content of CTZ, that is, the current position of the machine, is compared with the area DDI, and while the current position of the machine is within the deceleration area DDI, the deceleration signal DEC is applied to the tangential speed calculation circuit ART via the data output device DO to calculate the feed rate. Slow down.

That is, the processor CPU reads the machine's X at regular intervals,
Regarding the z-axis current position While both are established simultaneously, the deceleration signal DEC is generated.

Next, when the tracing reaches the +X limit, finishing big feed (pick feed amount ΔPy) is performed on the Y-2 plane.

Processor CPU Y-axis current position (yl + ΔP)
Determine which divided area belongs to and calculate y□≦(y1+ΔP
)<y□0Py, the comparison calculations shown in equations (2) and (3) using (X 1 s Z 1 ) corresponding to the first divided area of Table 1 are performed again.

Similarly, when the current Y-axis value reaches the second divided area DY2, P2 (X2 jz2
) is used to set the deceleration region DD2, and similar comparison calculations and deceleration control are performed.

Figure 5 shows the detection circuit M for sudden changes in model shape in Figure 4.
An example of the configuration of D is shown.

In the case of X-2 plane tracing, the detection circuit MD detects the Y-axis and two-axis variations (n components ε, ε) of the stylus of the tracer head.
is input to the delay circuit DLY1.

X Z DLY2, an adder circuit ADDI that adds the output of each delay circuit and the corresponding displacement component with mutually opposite polarities;

ADD2, an adder circuit ADD3 that adds the outputs of these adder circuits ADD1 and ADD2, compares the output of this adder circuit ADD3 with a predetermined voltage value PDV, and outputs "1" when the output of the adder circuit ADD3 exceeds the value PDV. ''.

FIG. 6 shows another embodiment of the detection circuit MD for detecting sudden changes in model shape, and detects stylus axis components ε and ε.

Absolute value circuits ABX and ABY input ε.

ABZ, an adder circuit ADD4 that adds these outputs, a differentiator circuit consisting of a capacitor C and a resistor R that differentiates this output, and when the output of the differentiator circuit and a predetermined voltage PDVI are compared and the former is greater than the latter. The comparator circuit COMP2, which produces the output itl''', has a configuration L7.

Still, the displacement direction signal si in the indexing circuit IND in FIG.
The displacement angle θ is determined from nθI eO8θ, and when the temporal change in the angle θ exceeds a certain value, it can be assumed that the shape of the model has suddenly changed.

In addition, in the above embodiment, when setting the deceleration region regarding the sudden change position of the model shape, the pift-yield amount Py during rough machining was used for the DY axis (pick feed axis), but a value other than this was used. You can also use the Y axis,
Regarding the Y axis, the parameters δ can also be set to different values.

As described above, according to the present invention, the acceleration time is shortened because the feed rate is reduced and the profile machining is performed only in areas where the model shape suddenly changes, such as corners, without reducing the profile machining speed overall. However, it has the advantage of being able to accurately pattern and process sudden changes in the model shape.

A model shape sudden change detection circuit detects from an output signal of the tracer head that the tracer head has reached a sudden change part in the model shape during the tracing process, and a machine when the model shape sudden change detection circuit detects the sudden change part. Since it is equipped with a model shape sudden change position storage means that detects and stores the position, there is no need to manually input the area where deceleration is to be performed. Since there is no need to paste the paper, it has the advantage of being easy to handle.

[Brief explanation of the drawing]

Figures 1 and 2 are a diagonal diagram of a model with a part where the shape changes suddenly and its plan view, Figure 3 is a tracing path diagram for finishing and finishing, and Section 4 is a tracing apparatus that implements the method of the present invention. The block diagrams of FIGS. 5 and 6 are the detection circuit M of FIG.
Examples of configurations of D are shown below. In the figure, KB...Keyboard, OPP...Operation panel, Dll, DI2...Data input device, D. ...Data output device, Ml...Data memo! ,I,
M2...Control program memory, CPU...
・Processor, MD...detection circuit for sudden changes in model shape,
CNTX. CNTY, CNTZ...Reversible counter, pcx. pcy, pcz...position detector, DC...distribution circuit.

Claims (1)

[Claims] 1. In a tracing control device having means for calculating a tracing feed direction and tracing speed from an output signal of a tracer head that traces a model surface, when the tracer head reaches a sudden change part of the model shape during tracing. The model shape sudden change detection circuit detects this from the output signal of the tracer head, and the model shape sudden change position storage means detects and stores the machine position at the time when the sudden model shape change detection circuit detects the sudden change part. A tracing control method characterized in that, during machining, when the stylus of the tracer head reaches an area having a predetermined width that includes the machine position represented by the stored machine position information, the tracing speed is reduced. 2. Claims characterized in that the tracing area is divided into a plurality of areas with respect to the pick feed axis, and machine position information corresponding to the position where the model shape suddenly changes is input and stored for each divided area. The profile control method described in Section 1.