JPS60123251A - Interactive type numerically controlled machine - Google Patents

Abstract

PURPOSE:To smoothly cut upward a workpiece, by providing such an arrangement that an output instruction is delivered to a servro-pump in accordance with the deviation between an instructed moving amount from a CPU and a feed-back moving amount, and therefore, the workpiece is cut upward at the time when the sign of moving amount counter varies. CONSTITUTION:When judgement is made such that the sign of a moving amount counter 12 varies after a target on the Z-axis is over, and when the sign of a remaining distance PR varies, pulse distribution is stopped, and therefore, a constant speed section may be obtained from a Z-axis cut-up starting point 23 to a completing point 24 by prose-cuting a deceleration instruction, and therefore, a workpiece is cut upward while a screw pitch is maintained constant. Further, the cut-up is started along the X-axis when the target on the Z-axis is over. However, judgment on the cut-up is known by observing a change in the sign of the a moving amount counter 12. Accordingly, smooth cut-up is automatically carried out without the causes of feed-back, etc. in a machine being considered.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an interactive numerical control device, and more particularly to a numerical control device for automatically rounding up threads during thread cutting.

Configuration of conventional example and its potential problems In thread machining using a conventional numerical control device, for example, as shown in Fig. 1, a workpiece (1) held by a chuck (41) is
When machining a thread with an effective length (21), the thread is machined according to the command of address code G32. Grooving must be done in advance.This coasting distance (δ) is usually calculated as δ=TXτ...
(1) Here, the amount calculated by the formula where T = time constant of the mechanical system = feed rate is calculated by the user, or mJL
It is calculated using monographs, etc., and then a program is executed in NC language based on the calculation, and thread machining is performed after groove machining.

In addition, in a conventional numerical control device having a fixed cycle with address code G92, the cutting angle is fixed at 45 degrees,
The amount of rounding up is determined by setting the pitch of the thread as α, and the amount of upturning of the thread as IL2Q.

In either case, there is a drawback that the set value must be calculated taking into account the gain including the mechanical system, and in actual operation, the user must contact the machine manufacturer or numerical control equipment manufacturer. It is necessary to calculate the coasting amount and round-up amount using a simple conversion table, etc. and run the program.

Purpose of the Invention The present invention eliminates the above-mentioned drawbacks of conventional numerical control devices, and provides a numerical control device that can smoothly round up screws without considering mechanical system gains or machine-specific parameters. The purpose is to provide the following.

Composition of the Invention The present invention retrieves the deviation between the amount of movement command from a central processing unit, which is configured as a discrete device or stored in memory, and the amount of movement fed back from a mechanical movable part into a total deviation register, and uses this deviation register to control a servo amplifier. A movement amount counter is provided to detect the difference between the target value given by the same central processing unit and the actual movement amount of the moving parts of the machine, and when the sign of this movement amount counter changes, When rounding up is performed and it is necessary to round up all of a plurality of axes, the above-mentioned configuration is adopted for each axis.

DESCRIPTION OF THE EMBODIMENT FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. In the figure, GO is a central processing unit (CP-U),
QW, (u') is the deviation register, ■ is the movement amount counter,
Q3. What about (13')? -H7 mp, (141, (1
4') is the servo motor, (15) is the entire encoder, αD to α9 are for moving the mechanical movable parts in the two axes directions shown in Fig. 1, (11), (13) to (15) '
) is for movement in two axial directions. The movement amount counter is provided only for the z-axis that requires rounding up.
It is not provided on the Z axis.

The deviation register ALL is configured discretely in the central processing unit α0 or outputs the difference between the movement command amount given from the contents stored in the memory and the position feedback amount given from the mechanical movable part through the encoder output. In addition to the servo amplifier 03, the servo motor α4) is fully driven, and its output is controlled by the following equation.

Varrp= (Pi −Po) Kv・・・・・・
・・・・・・・・・・・・・・・・・・(21 However, Vam
p=output Pi of deviation register 011=movement command amount Po=feedback amount Kv=loop gain Further, the movement amount counter a2 is for monitoring the target value and is used as shown in the following equation.

PR=(P, -P.)・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(3) However, P
R= Remaining distance P, - Target value Po - Feedback amount Before explaining the details of the present invention, the operation of thread cutting when the movement amount counter in Fig. 2 does not respond will be explained with reference to Fig. 5. do. Figure 3 illustrates the movement of the slide, which is the mechanical movable part, in this case. Move the slide from the original position ■ to the cutting point υ, maintain the full pitch by the effective length of the screw from the depth of cut (a), and cut up to the starting point c! When reaching 3, is the speed of the 2-axis direction from the round-up starting point @ the same speed? round up at a constant speed in the X-axis direction. At this time, if the same X coordinate as the cutting point υ is set as the target point, the movement of the slide is rounded up at the composite speed of the two axis directions and the X axis direction. However, in the X-axis direction, the movement amount command to the deviation register αP is completed before reaching the same position as the cutting point, and the pulse distribution is completed at point (a). When the pulse distribution is completed, pulse distribution is stopped for both the Z and Z axes, and the point (A) is reached where the remaining value of the deviation register for each axis becomes 0. The problem here is
By completing the pulse distribution at point (c), the x-axis,
Both Z-axes start decelerating f! ', it is not possible to maintain the thread pitch in the z-axis direction, and it is not possible to round up smoothly.

This is because there is a delay between the movement command and the actual movement of the slide. Regarding the X axis that determines the end, ε = 6...・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
(41) However, ε = Remaining amount of deviation counter τ = Feed speed Kv = Ends with the amount expressed by gain remaining.

Furthermore, this pulse distribution completion point) is determined by the depth of the thread, the pitch of the thread, and the rotation speed of the main shaft.If we assume that the cutting point, the shiba, and the russ distribution completion point are above Kfj<, the pulse distribution completion point is determined. Leaving it up to the user to add an offset amount to , would inevitably result in the same result as described for the conventional example, which would be cumbersome.

FIG. 4 is an explanatory diagram of the round-up operation of the present invention when the deviation register ab and the movement amount counter C12 are used together. The sliding operation from the original position (2) to the cutting edge lifting start point c23 in FIG. 4, that is, the moving operation of the mechanical movable part, is the same as that described with reference to FIG. 5. From the rounding up starting point ■ - is the speed in the X-axis direction, that is, the pitch of the screw. f''1 is rounded up at a constant speed in the direction of the two axes. At this time, the determination of the completion of movement in the X-axis direction is not made by the deviation register a1), but by the movement amount counter (2) in FIG. In that case, the operation is performed according to the above-mentioned equation (3).For example, if the target value is the same amount as the cutting point Q1 in Fig. When the sign is reversed, it is determined that the slide is actually at the target value (c) and the thread has been completely cut up.

If we stop the pulse distribution on both axes in 2.2, the pulse distribution is actually done by A''!f in (2), but the remaining amount in the deviation register of the Z and Z axes is OK, A
The slide stops at (4). From the above points (2) to (a)
Although it is a deceleration operation up to, no problem occurs because the rounding up has already been completed. Furthermore, if necessary, it is also possible to reduce the remaining v amount at the time when pulse distribution is completed to accelerate deceleration.

Figures 5 and 6 show flowcharts of the thread cutting operation corresponding to the thread cutting operation shown in Figures 5 and 4, respectively. When the 2-axis target (31) in Figure 5 is exceeded and the predetermined target of z#I is exceeded, the Z-axis is turned off! 1ll-thorn is started,
In (32), it is determined whether pulse distribution has been performed for the amount of movement equal to the rounded-up amount, and when the pulse has been distributed by the predetermined amount of movement, (
It stops at the third blade, and then moves from (E) to the blade in Figure 3 using the remaining amount of the deviation register. As a result, the cut-up portion cannot maintain a constant velocity and the thread pitch cannot be maintained.

Fig. 6 corresponds to Fig. 4, and after the 2-axis target exceeded in % and (31), the sign change of the movement counter ■ is judged (3
6). Since this follows equation (3)K, when the sign of the remaining distance changes, the pulse distribution is stopped (C3) and the deceleration command (37) 'fr is executed. ) can be obtained, and rounding can be performed while maintaining the entire thread pitch.

Z-axis starts rounding up when the Z-axis target is exceeded (31), but the rounding-up is determined when the two-axis pulse distribution is completed 02
) then (, the sign change of the Z-axis movement amount counter is (36
), it is possible to automatically cut and heave smoothly without considering factors such as the machine's feedback cane.

Effects of the Invention As described above, the present invention detects the difference between the actual amount of movement of the slide and the target value using the amount of movement counter, and determines that the screw has been cut up when the sign of the amount of movement counter changes. Since the pulse distribution is stopped at this point, the pitch of the thread can be maintained at the end of the thread cut, and unlike conventional methods, the user has to adjust the thread pitch based on machine-specific factors such as feedback gain. Rounding up can be performed automatically and smoothly without considering all the original parameters.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of thread machining using a conventional numerical control device.
FIG. 2 is a block diagram showing the configuration of an embodiment of the interactive numerical control device of the present invention, FIG. 5 is an explanatory diagram of the round-up operation in the case where the movement amount counter ■ in FIG. 2 is not provided, and FIG. FIG. 2 is an explanatory diagram of the rounding-up operation using the deviation register and the movement amount counter in combination, FIG. 5 is a flowchart explaining the rounding-up operation of FIG. 5, and FIG. 6 is a flowchart of explaining the rounding-up operation of FIG. 4. (1) -- Workpiece, (21 -- Effective length of screw,
(3)...Coasting, (4)...Chuck, αl.
-・Central processing unit, αD. (11') --- Deviation register, j... Movement amount counter, a3゜ (13') --- Servo amplifier, (1
41, (1'+') - Servo motor, morning. (15') - Encoder, ■υ... Cutting point, (4)... Cutting depth, (A) - 2-axis cutting, lifting start point, (C) - All cutting completed point, pulse distribution completion point for (c), reached position. Name of agent Patent attorney Etsuji Yoshizaki Figure 2 1 - - - - , J Figure 5 M6

Claims (1)

[Claims] The deviation between the amount of movement commanded by the central processing unit and the amount of movement of the machine's movable parts is used as a drive output to create a deviation register for extracting the sheets, and the actual movement angle of the machine's movable parts in the axial direction that requires rounding up for thread cutting. - and a movement amount counter for detecting the difference between the movement amount counter and a target value, and the interactive numerical control device is characterized in that the completion of rounding up of thread cutting is determined by a change in the movement amount counter.