JPS5912421B2 - Tracing control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracing control method that automatically controls the start position of deceleration control in a system in which deceleration control is performed immediately before the stylus of a tracer head contacts a model.

As shown in Figure 1, clamp copying, in which the parts below the limit switch LSZ are fed in the horizontal direction without copying, is used when cutting with a press or the like or cutting by a predetermined amount at a time. Place a limit switch LSZ at
Alternatively, the limit switch LSZ' is moved by a predetermined depth of cut in the direction of the arrow for each copying process, and the tracer head is fed in the horizontal direction after the limit switch LSZ'.

In this way, the limit switch LS
If the cross section of the model on the plane parallel to the XY plane passing through Z is as shown in Figure 2, limit switches LXI,
LX2 is placed, and deceleration control is performed when limit switch LX1 is activated when the scanning feed direction is in the -X direction, and when limit switch LX2 is activated when it is in the +X direction, and the right side of the model and the limit are The section m between the switch LX1 and the section n between the left side of the model and the limit switch LX2 are fast-forward sections, and the limit switches LXI, LX2 and the model M facing these
The deceleration section q is between the DL and the DL.

Even if this deceleration section q is initially set, the model MD
Depending on the shape of L, the deceleration section increases as shown in q' and becomes longer than necessary, which affects the machining time.

The present invention improves the above-mentioned conventional drawbacks, and aims to automatically control the deceleration section so that the necessary minimum deceleration section is always obtained, thereby shortening the machining time.

Examples will be described in detail below.

The present invention determines the next deceleration control start position based on the displacement direction of the stylus of the tracer head when it comes into contact with the model and the displacement due to pick feed, and sets this deceleration control start position approximately at the tracing start point of the model. It is designed to fit the shape of.

FIG. 3 shows a principle diagram of an embodiment of the present invention.

In this figure, the cross section of the model is shown in a straight line for easy understanding.

+LXE, -LXE indicate big feed limit,
Points P1 to P22 indicate the movement path of the stylus.

That is, when the copying in the -X direction starts from Pl and the model is copied up to P2, the limit switch LSZ shown in FIG. 1 is activated to perform clamp feed, and the stylus is rapidly fed.

At P3, limit switch LX 1 operates, deceleration limit switch LX 1 operates, switches to deceleration feed, and P
Touch the model MDL at step 4 to finish clamp feeding, and press P.
Model MDL is copied from 4 to P5.

By operating the limit switch -LXE, pick feed is performed in the +Y direction, the stylus is fed by the pick feed amount PF1, the copying direction is switched to the +X direction, and copying is performed from P6 to Pl.

The limit switch LSZ is operated again at Pl to perform clamp feeding, and the feed is fast-forwarded and decelerated at a point P8 where the limit switch LX2 is activated.

It touches the model MDL at P9 and the clamp is released, and Pl
Limit switch +LXE operates at o and moves P in the +Y direction.
F2 is pick-fed and Pll switches to -X direction scanning again.

In the present invention, the pick feed is performed in areas other than the four parts of the model where the stylus is clamp fed.

In the present invention, for example, in the case of scanning in the -X direction, limit switch LX 1 is set so that the distance between limit switch LX 1 and P4 is the optimum deceleration distance l, and Pl
By effectively shifting the deceleration start position in the stroke from P1 to P16 by the model shape change amount ΔL1 from the initial position of the limit switch LX1, deceleration is started 1 point before P15.

The same applies to the deceleration in the +X direction from Pl to P22, and by effectively shifting the deceleration start position from the initial limit switch LX1 position by the model shape change amount ΔL2, the deceleration start signal is set 1 point before PZ1. make sure you get it.

Model shape change amount ΔL1. ΔL2 is calculated from the previous two big feed amounts and the previous stylus displacement direction.

The example in Figure 3 shows a model with a linear shape, but any curved shape can be considered equivalent to Figure 3 if the pink feed amount is appropriately small relative to the shape change. .

FIG. 4 is a block diagram of an embodiment of the present invention.
is the mechanical moving part, MX, MY, MZ are the motors, PX, PY
, PZ is a position detector such as a pulse coder, TR is a tracer head, ST is a stylus, MDL is a model, CT is a cutter, W is a workpiece, SEL is a selector, SQC is a sequence circuit, DX, DY, DZ are motor drive circuits, G.C.L.
GC2 is a gate circuit, ALU is a scanning calculation circuit, APC is an approach circuit, PFC is a pick feed circuit, CPS
is a clamp feed circuit, CMPI is a comparison circuit, and DCC is a deceleration signal generator.

εy and ε2 are copied to the detection signal of the tracer head TR and added to the calculation circuit ALU to calculate the feeding direction and feeding speed,
Control for machining a workpiece W that follows the shape of the model MDL is well known.

FIG. 5 is a detailed block diagram of the deceleration signal generator DCC in FIG. 4.

In the figure, AD is an analog-digital converter, R
θ1°Rθ2 are registers, RC1, RC2, RB,
RAI.

RA2 is a counter, MUL is a multiplier, ADD is an adder, CMP2 is a comparison circuit, opp is an operation panel, GC3
~GC5 represents a gate, and G1 and G2 represent an inhibit gate.

FIG. 6 shows an operation flowchart of the embodiment of the present invention shown in FIGS. 4 and 5. FIG.

First of all, the initial setting is limit switch LSZ.

+LXE, -LXE, and LYE are set, and the initial deceleration position is determined by moving the machine in advance using manual feed button JB, positioning the stylus in sequence at LXI and LX2 positions, and pressing teach buttons BTI and BT2, respectively. The counters RAI and RA2 are preset.

Next, when the start button is pressed, the sequence circuit SQC starts the approach circuit APC and gates GC1 and G
The tracer head TR is moved in the -Z direction by moving C2 to T5I, and when the stylus ST contacts P1 in FIG. 3, this is detected by the comparator CMP1 (ε-ε).

-0) and shifts to -X copying. The output pulses from the position detector PX are always accumulated in the counter RB.

When limit switch LSZ operates at P2 in Figure 3,
Activate the clamp feed circuit CPS and send the tracer head in the -X direction with rapid traverse.

Comparator CMP2 compares the contents of counter RA1 and counter RB when copying -X, and calculates (RA1) = (R
B) When this occurs, the deceleration start position DEC is generated, the clamp feed is stopped at low speed, and the counter RC1 is reset.

Stylus contact with the model is detected at P4 in Figure 3 (ε-ε
.

-〇), the register Rθ1 is gated, and the value of tanθ1 outputted from the scanning calculation circuit ALU at that time is read into the register Rθ1 via the AD converter.

Here, tan θ is constantly calculated and outputted by the scanning calculation circuit ALU as a ratio of the pick feed direction component εy to the clamp feed direction component εX at the good scanning end of the tracer head.

When the X limit -LXE is detected at B5, the pick feed circuit PFC is activated, and pick feed of PFl is performed in the +Y direction, and the movement amount PF1 of the tracer head in the Y direction during this pick feed is calculated by counters RCI and RC.
Accumulated to 2.

Then, +X follows, and the comparison circuit CMP2 becomes (RA2
) and (RB), and when they match, a deceleration start signal DEC is sent out.

At point B9, register Rθ2 is gated and ta
The value of nθ, tanθ2, is read into register Rθ2.

Pick feed is performed again at Plo, and the output pulse YP from the detector PY corresponding to the amount PF2 is sent to the counter RCI.
, are accumulated in RC2.

When the pick feed is completed in Pll, the counter RC
1 holds the value (PF 1 + PF 2 ), and (Rθ1) and (RCl: are applied to the multiplier MUL through the gate GC3, and ΔL 1−(PF 1 +PF 2) X tanθ1
(2) is calculated and the operation (RA1) + ΔL1 → RA1 (adds ΔL1 to the contents of counter RA1 and stores it in counter RA1) is performed by adder ADD via GC4. It will be done.

As a result, the counter RA1 indicates the position of PI3, that is, a position 1 before PI3.

Therefore, the deceleration start signal DEC is obtained at PI3 points.

Similarly, at PI3 points, the value of counter RC2 is
F 2 +PF 3), and the register Rθ2 is t
Since the value anθ2 is held, ΔL 2 ”” (
PF 2 + PF 3) X tanθ2 -----・
-(3) is calculated, and the following operation is performed: (RA2)+ΔL2→RA2.

As a result, the contents of the counter RA2 indicate the position 1 before the PI3 point, that is, B21, and the deceleration start signal DEC is obtained at the PI3 point.

FIG. 7 shows a principle diagram of a second embodiment of the present invention, FIG. 8 shows a block diagram of the second embodiment, and FIG. 9 shows an operation flowchart thereof.

In FIG. 8, CMP3. CMP4, CMl.

CM2 is a comparison circuit, DET is a rising edge detection circuit, MUL
1, MUL 2 is a multiplier, AI.

Bl, CI, A2, B2, C2 are counters, P
DTl and PDT2 are direction determining circuits, 03 to G11 are ant game), DI and B2 are OR gates, and L is a register.

Further, +TC and -TC are +X tracing and -X tracing signals, respectively, and CLP is a clamping signal which is generated from a sequence circuit not shown.

In this embodiment, the distance l from the model surface to the deceleration start position as seen from the model surface is set in the register, and for example, in the case of scanning in the ~X direction, the counters Al and B1 are reset at the point P2 where the stylus contacts the model. Counter A1 counts pulses from the X-axis position detector to indicate the current position of the stylus in the X direction with reference to point P2, while counter RB1 counts pulses from the deceleration start point P11 in the stroke, that is, the stroke from B9 to PI3. In order to determine this, the contents are modified by the model shape change ΔL1.

That is, prior to clamp copying from Plo to B13, counter B1 starts counting the pulses of the X-axis position detector from point P9, counts for 351 minutes, and holds the content.

At this time, counter B1 indicates the position of point B13 as viewed from B2.

The determination of deceleration point P11 is (AI) - (B1) = 1.
- Performed by (4).

Also, when model contact is detected at P13, counter A1. Both B1 are reset and the same operation is repeated thereafter.

The same applies to +X copying, and the counters RA2 and R
B2 is provided, and counters A2 and B2 are provided that are reset at the model contact point P7 in order to determine the deceleration start point P17 in the process from B15 to B20, and the counter RA2 is the current position of the stylus in the X direction with reference to point P7. Count the output pulses from the X-axis position detector as shown in
The contents of the counter B2 are modified by the model shape change amount ΔL2 prior to the clamp copying process P16 to B19 in the process from B15 to B20.

That is, at B15, the counter B2 starts counting pulses from the position detector, counts the pulses by ΔL2, and holds the contents.

At this time, counter B2 indicates the position of point B19 viewed from B7.

The determination of deceleration point P17 is (A2)-(B2)=1 ・・・・・・・・・・・・(
5).

Also, when model contact is detected in P19, counter A
1. Both B2 are reset and the same operation is repeated thereafter.

In this embodiment, the displacement direction (tanθi, tanθ2) when the stylus contacts the model is detected, and the pick feed amount (PFl, PF2°...
...) is performed in the same manner as in the previous embodiment, and the deceleration start point P1,
B6 shall be manually commanded by the operator.

In Fig. 7 B2, under the conditions of clamping and -X tracing, the output of G4 becomes "1", and the counter Al
, B1 are reset, and the stylus displacement direction tanθ1 at that time is stored in the multiplier MUL1.

When the 21st pick feed is completed in B9, the even number end signal PEF becomes 1'', and the contents of the counter C1 (
PF i +PF 2) and the tan θ
1, ΔL 1 = (PF 1 + PF 2 ) tanθ1
(6) is obtained by the multiplier MUL 1 and ΔL1 is set in the counter CM1.

In the process from B9 to Plo, the output pulse XP of the position detector is applied to the counter B1 via the gate G6 and is accumulated.

At this time, the output pulse XP is also applied to the counter CMI to reduce its content, and when it becomes zero, G6 is closed.

As a result, counter B1 is equal to ΔL set in counter CM1.
1 has been made, and the direction discrimination circuit PDT 1 supplies the output pulse XP to the subtraction and addition inputs of the counter B1 according to the sign of tanθ1, so that the counter B1 changes the point P13. It will be shown.

When the comparison circuit CMP4 is -X, the gate G8
．． Counters Al and B1 are input via GIO, (AI)-(B1) = 1...
. . . (7) is always made, and when this is true, the deceleration start signal DEC is generated.

When this deceleration start signal DEC is generated, the counter C1 is reset.

For 10X copying, multiplier MUL2, odd-numbered pickfeed end signal POF, direction discrimination circuit PDT2,
Gate G7, counter A2°B2. CM2. C2, gate G9. G11 and comparison circuit CMP4 perform the same operation as in the above case, and the correction amount of counter B2 is ΔL 2-(
PF 2 +PF3)

As explained above, according to the present invention, the amount of change in model shape is measured by an operator based on the stylus displacement direction and the pick feed amount when the stylus contacts the model during clamp copying, and the deceleration start position is kept constant from the model surface. Since the deceleration feed distance is controlled to be at the position of , it is possible to completely eliminate the defects of the conventional method, such as the reduction in the efficiency of copying machining due to an unnecessarily large deceleration feed distance.

Note that if you perform pickfeed when the stylus contacts the model with clamp feed, you can measure the amount of shape change at the starting edge of the model from the positions of the pickfeed start and end points. It becomes extremely difficult to carry out clamp copying in the reciprocating direction as shown in FIG.

In the case of the present invention, since the amount of change in shape is measured by an operator, not only unidirectional scanning but also reciprocating scanning is easily possible.

Additionally, if the stylus contacts the model with clamp feed and pick feed is performed, the tracing path inside the recessed part of the model will not be straight, resulting in a problem with the finish of the machined surface, but this does not occur with the present invention. .

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of clamp copying, Figure 3 is a principle diagram of the first embodiment of the present invention, Figure 4 is a block diagram of the first embodiment, and Figure 5 is the same as that of Figure 4. A block diagram of the deceleration signal generator, FIG. 6 is a flowchart explaining the operation of FIGS. 3 to 5, FIG. 7 is a principle diagram of the second embodiment of the present invention, and FIG. 8 is a block diagram of the second embodiment. 9 shows a flowchart explaining the operation of FIGS. 7 and 8. MDL is the model, TR is the tracer head, ST is the stylus, MX, MY, MZ is the motor, and PX. PY, PZ are position detectors, ALU is scanning calculation circuit, AP
C is the approach circuit, PFC is the pick feed circuit, C
PS is a clamp feed circuit, DCC is a deceleration signal generator,
SQC is a sequence circuit, and GC1 and GC2 are gate circuits.

Claims (1)

[Claims] 1. Pick feed is performed in an area other than the concave part of the model where the stylus is clamp-fed, and the tracer head moves from a fast-forward operation to a deceleration operation when the stylus of the tracer head contacts the model, thereby reducing the impact of the stylus on the model. In a tracing control method that alleviates this, the amount of shape change at the tracing starting edge of the model is calculated as the ratio of the pick feed direction component to the clamp feeding direction component at the tracing starting edge of the tracer head from the previous tracing starting edge in the same direction. By multiplying the amount by the operator, the deceleration start position where the tracer head transitions from rapid forward motion to deceleration motion with respect to the profiling start end of the model that comes into contact with the next clamp feed in the same direction is calculated by multiplying the amount by an almost constant value from the profiling start end of the model. A copying (middle leg method) characterized in that control is performed in accordance with the amount of shape change measured by the operator so that the distance is the same.