JP2713566B2 - Numerical control device for tapping - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to tapping, specifically, a general tapping tool without using a tap unit (hereinafter simply referred to as a tapper) having a tap attached to a floating tap chuck. The present invention relates to a numerical control device for tapping for performing synchronous tapping by using. [Prior Art] FIG. 4 shows a conventional numerical controller of this type.
In the figure, (1) is a central processing unit (hereinafter, referred to as a numerical control unit) of the numerical controller.
(2) is a Z-axis drive unit that controls the vertical axis of the tapper, (3) is a spindle drive unit that controls the rotary spindle of the tapper, and (4) is driven by the Z-axis drive unit (2). (5) is a spindle motor driven by the spindle drive unit (3), (6) is a tapper for performing tapping, and is a machine side together with the motors (4) and (5). Attached to. (7) is a work. The conventional numerical controller is configured as described above,
When (1) decodes a tap machining command in a machining program read from a machining program input unit (not shown),
The main shaft forward rotation command and the main shaft rotation speed Srpm are transferred to the main shaft drive section (3). Thus, the spindle drive unit (3) rotates the spindle motor (5) forward at a rotation speed of Srpm. On the other hand, the Z-axis driving unit (2) receives the movement amount -Z of tapping in the machining program from the CPU (1), drives the Z-axis motor (4), and feeds the ball at a feed speed (pitch) via a ball screw. The work (7) is processed by lowering the tapper (6). Here, on the command of the program, the feed rate is designated by the pitch of the thread, and the actual feed rate is the pitch [mm / rotation] designated by F × the number of revolutions S of the main spindle [rotation /
Min], and the Z axis is controlled at that speed. When the tapper (6) has moved by -Z, the CPU
(1) gives a reverse rotation command to the spindle drive unit (3) and gives the Z movement amount to the Z-axis drive unit (2). For this reason, the Z-axis motor (4) rotates at the feed speed F (pitch) and attempts to raise the tapper (6). On the other hand, since the spindle motor (5) rotates in the reverse direction, the tapper (6) rises by the distance Z that is tapped while rotating in the reverse direction. In order to perform tapping accurately, it is necessary to synchronize the rotation angle of the spindle motor (5) with the Z-axis motor (4) controlling the feed amount of the tapper (6). However, in the conventional tapping, the spindle motor (5) and the Z-axis motor (4) are separately controlled as described above, so that the rotation angle of the spindle motor (5) and the feed amount of the tapper (6) are different. In the tapping of the machine tool, the tapper (6) uses a tap attached to a floating tap chuck that can expand and contract in the direction perpendicular to the rotation direction so that the synchronization may be slightly shifted.
After the movement of the Z axis is stopped, if the spindle motor (5) is rotating, the tap expands and contracts in accordance with the spindle rotation angle, and the tap can be moved in accordance with the spindle rotation angle. However, if the tapper (6) is interposed between the spindle motor (5) and the Z-axis motor (4) for feed control, the inertia rotation of the main shaft at the movable end of the telescopic mechanism can be performed, although it can cope with the inertia rotation of the spindle in the normal state. In addition, the distortion caused by the axis movement of the Z-axis motor (4) in the feed control during the reverse rotation from the stop of the spindle cannot be absorbed, and the hole bottom accuracy is deteriorated by the flow of the tap at the hole bottom. For this reason, in the conventional tapping, there is a problem that the flow of the tap at the hole bottom must not exceed the play range of the tapper (6), and high-speed machining cannot be performed. Although omitted in the above description, the CPU (1) realizes a function as a numerical control device by reading a control program stored in a memory (not shown) one step at a time and executing the instruction. [Problems to be Solved by the Invention] When tapping is performed by the conventional numerical control device as described above, when the spindle is reversed, the inertia of the spindle is larger than the inertia of the Z axis. And the position error between the spindle rotation angle and the feed axis Z increases because the gains of both axes do not match, and there are problems such as breakage of the tap and crushing of the thread of the tap. Also,
Since the continuous operation from forward rotation to reverse rotation was not successful, the tapper (6) had to be used without fail. For this reason,
There are problems such as that the tapper (6) becomes expensive and that tapping at high speed is difficult. The present invention has been made in order to solve such a problem. In addition to tapping using a tap without a floating tap chuck, tapping can be performed at a high speed by improving machining accuracy at a hole bottom. The purpose of the present invention is to obtain a numerical control device. Means for Solving the Problems The numerical control device for tapping according to the present invention has a built-in arithmetic unit that outputs a spindle acceleration / deceleration command based on a preset spindle gain, acceleration / deceleration pattern, and time constant. Drives the tap control axis by incorporating a spindle drive unit that rotationally drives the tap spindle and an arithmetic unit that outputs acceleration / deceleration commands for the control axis based on a preset gain, acceleration / deceleration pattern, and time constant of the control axis. A numerical control device for tap machining, comprising: a control shaft drive unit for performing tap machining based on a machining program; and a control means for transmitting a command for performing tap machining to these drive units. The arithmetic unit of the shaft drive unit is configured to synchronize based on a synchronization control signal output from the arithmetic unit of the spindle drive unit to the arithmetic unit of the control shaft drive unit, The control means changes the gain, acceleration / deceleration pattern, and time constant of the control axis based on the input of the tapping command to match the gain, acceleration / deceleration pattern, and time constant of the spindle, and follows the tapping command in the machining program. The rotation angle of the main shaft is obtained based on the movement amount of the control axis and the feed speed, and the interpolation of the control axis and the main shaft is performed based on the movement amount of the control axis, the feed speed and the rotation angle, and the interpolation data sequentially correspond to each other. Along with transferring to the axis arithmetic unit, when each axis is driven synchronously by the drive unit of each axis and the control axis reaches the above-mentioned amount of movement, the amount of movement, the feed rate and the amount of movement in the opposite direction to the amount of movement of the control axis The rotation speed of the spindle and the control axis and the spindle are interpolated based on the reverse rotation angle in the opposite direction, and the interpolation data is transferred to the arithmetic devices of the corresponding axes.The spindle drive unit and the control shaft drive unit are Of each axis Deceleration pattern to between data, time constants, each axis with the acceleration-deceleration command consisting gain is characterized in that the driving in synchronization based on the synchronization control signal. Further, the control means changes the magnification of the feed speed command of the control shaft at the time of reverse feed to change the speed to an arbitrary speed. [Operation] In the present invention, the gain, acceleration / deceleration pattern and time constant of the control axis are matched with the gain, acceleration / deceleration pattern and time constant of the main axis to adjust the acceleration / deceleration commands of both axes, and the synchronization of the main axis and the control axis is performed. Since tapping is not performed, tapping can be performed with a tap that does not use the floating tap chuck, and further, the return speed is increased to enable high-speed tapping. Embodiment FIG. 1 shows an embodiment of the present invention, in which the same reference numerals as those in FIG. 4 denote the same or corresponding parts. (6 ') is a tap that does not use a floating tap chuck,
(8) is an arithmetic unit provided in the Z-axis drive unit (2).
The acceleration / deceleration pattern for the spindle, the time constant for determining the acceleration and deceleration slopes of the acceleration / deceleration pattern, and the gain for determining the ratio of output to input in the servo system are added to the acceleration / deceleration pattern for the Z axis. Match the deceleration pattern with the time constant and gain. (9) is an arithmetic unit provided in the spindle drive unit (3), and calculates an acceleration / deceleration command of the spindle motor (5) based on the rotation angle α of the spindle given from the CPU (1). Here, the rotation angle α of the main shaft is obtained by the following equation (1) by the CPU (1). α [pulse] = {Z-axis movement amount / pitch} × 1,000 [pulses] × 360 [degrees] (1) Further, (10) is a Z-axis arithmetic unit (8) and a main axis arithmetic unit (9) ), And transmits a spindle acceleration / deceleration start command or the like from the spindle arithmetic unit (9) to the Z-axis arithmetic unit (8) via the connection line. FIG. 2 is a flowchart showing a tapping method by the numerical controller shown in FIG. 1, and will be described below with reference to FIG. When the tap command is input to the CPU (1), the CPU (1) reads the gain, acceleration / deceleration pattern, and time constant of the spindle, which are set in advance in a memory (not shown) of the arithmetic unit 9 of the spindle.
The Z-axis gain, acceleration / deceleration pattern, and time constant are written into a memory (not shown) of the Z-axis arithmetic
Adjust to the acceleration / deceleration pattern and time constant (step (2
1)). More specifically, when a command is issued from the CPU (1) to the spindle computing device 9 by a synchronous machining command, the computing device 9 reads the acceleration / deceleration pattern for the spindle, and the time constant and gain values from predetermined memory addresses. Transfer to CPU (1). Subsequently, the CPU (1) transfers the above values to the arithmetic unit 8 of the control axis. The arithmetic unit 8 stores the respective values in predetermined memory addresses in the arithmetic unit so that the acceleration / deceleration pattern, time constant, and gain for the Z-axis match the acceleration / deceleration pattern, time constant, and gain for the main axis. Then, the CPU (1) reads and executes a control program stored in a memory (not shown), decodes a tapping command in the processing program, and obtains a rotation angle α of the spindle based on the above equation (1) ( Step (22)). The spindle arithmetic unit (9) extracts an acceleration / deceleration command including the acceleration / deceleration pattern, time constant, and gain for the spindle based on the storage address of the gain, acceleration / deceleration pattern, and time constant of the spindle (step (23) )) Also, the Z-axis arithmetic unit (8)
Is stored in the Z-axis motor (4) based on the gain, acceleration / deceleration pattern and time constant of the spindle (step (24)). Next, the CPU (1) determines the Z-axis based on the Z-axis movement amount −Z ₁ , the Z-axis feed speed f ₁ (pitch), and the main shaft normal rotation angle α.
Interpolation between the axis and the main axis is performed (step (25)), and the data is transferred to the arithmetic units (8) and (9) for both axes. Arithmetic unit for Z axis (8)
Is the acceleration / deceleration pattern, time constant,
An acceleration / deceleration command including a gain is sent to the Z-axis drive unit (2) to rotate the Z-axis motor (4). On the other hand, the spindle arithmetic unit (9) sends an acceleration / deceleration instruction to the spindle interpolation data to the spindle drive unit (3) in the same manner as the Z-axis to rotate the spindle motor (5). In addition, the arithmetic device (8) for the Z axis and the arithmetic device (9) for the main shaft
There is a synchronization control signal (10) for synchronization between
The interpolation data and the acceleration / deceleration command are transferred from the spindle arithmetic unit (9) to the spindle drive unit (3), and at the same time, the synchronization signal (10) is sent from the spindle arithmetic unit (9) to the Z-axis arithmetic unit (8).
, The transfer of the interpolation data and the like to the Z-axis driving section (2) is started, and the simultaneous start of the Z-axis and the main axis is performed. In step (26), if the movement of the Z axis reaches -Z _1, CPU (1), in order to increase the tap (6 '), in step (27), the moving amount Z ₁ and Z-axis , Z-axis feed speed 2f ₁ , and reverse rotation speed α of the main shaft, and interpolates them to arithmetic units (8), (9) for both axes. In step (23), the Z-axis arithmetic unit (8)
An acceleration / deceleration command is added to the Z-axis interpolation data and sent to the Z-axis drive unit (2) to rotate the Z-axis motor (4). On the other hand, in step (24), the spindle arithmetic unit (9) sends an acceleration / deceleration command to the spindle interpolation data to the spindle drive unit (3) to rotate the spindle motor (5).
This operation is repeated until the tap sequence is completed for all hole positions in accordance with a series of drilling patterns instructed together with the tapping command (step (28)). In the above example, in step (27), since the feeding speed 2f ₁ in the Z-axis, in this case, can be processed at a high speed tapping cycle as the speed back as shown in FIG. 3 and 2 times . In the above embodiment, a case that the return rate f ₁ to 2 times, by changing the magnification of the set data in step (27) (= 2), can be changed to any speed. Further, in the above embodiment, linear acceleration / deceleration patterns are set in advance in the arithmetic device 9 for the main shaft and the arithmetic device 8 for the control axis, respectively. In the case of a linear acceleration / deceleration command as shown in FIG. However, the present invention is not limited to this, and an exponential acceleration / deceleration command may be used. [Effects of the Invention] As described above, the present invention synchronizes the Z axis with the main shaft, and matches the gain, acceleration / deceleration pattern and time constant of the control axis with the gain, acceleration / deceleration pattern and time constant of the main shaft. In addition to accelerating and decelerating commands for both axes and synchronizing the Z axis and the spindle, tapping can be performed with a tap without a floating tap chuck, which reduces the cost of the equipment and reduces the tap flow at the bottom of the hole. Since tapping is eliminated, high-precision tapping can be performed. In addition, if the return speed is increased, higher-speed tapping can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of a numerical control apparatus showing an embodiment of the present invention, FIG. 2 is a flowchart showing a tapping method thereof, and FIG. Deceleration command diagram, 4th
FIG. 1 is a diagram corresponding to FIG. 1 showing a conventional numerical control device. (1) CPU, (2) Z-axis drive, (3) spindle drive, (4) Z-axis motor, (5) spindle motor, (6 ') floating Taps without tap chuck, (8), (9) ... arithmetic unit, (10) ... synchronous control signal. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] A spindle drive unit that has a built-in arithmetic device that outputs a spindle acceleration / deceleration command based on a preset spindle gain, acceleration / deceleration pattern and time constant, and rotationally drives the tap spindle.
A control axis drive unit for driving the control axis of the tap, including a built-in arithmetic unit that outputs an acceleration / deceleration command for the control axis based on a preset gain, acceleration / deceleration pattern and time constant of the control axis, and a tap based on a machining program. In a numerical control device for tapping, which comprises a control means for sending a command for performing machining to these drive units, an arithmetic unit for the spindle drive unit and an arithmetic unit for the control axis drive unit are provided with a control unit for the spindle drive unit. The control unit is configured to synchronize based on a synchronization control signal output from the arithmetic unit to the arithmetic unit of the control axis drive unit, and the control unit controls the gain of the control axis, the acceleration / deceleration pattern based on the input of the tapping command. And the time constant to match the gain, acceleration / deceleration pattern and time constant of the spindle, as well as the movement amount and feed rate of the control axis according to the tapping command in the machining program. Based on the rotation angle of the main shaft, the control axis and the main shaft are interpolated based on the movement amount of the control axis and the feed speed and the rotation angle, and the interpolation data is sequentially transferred to the corresponding arithmetic units for the respective axes. When each axis is driven synchronously by the drive unit of each axis and the control axis reaches the above-mentioned movement amount, the movement amount and the feed rate in the direction opposite to the movement amount of the control axis and the rotation angle of the main shaft in the opposite direction. Based on the reverse rotation angle, the control axis and the main axis are interpolated, and the interpolation data is transferred to the corresponding axis arithmetic unit.The main axis drive unit and the control axis drive unit accelerate and decelerate the interpolation data of each axis. A numerical control device for tapping, characterized in that each axis is synchronously driven based on the synchronous control signal with an acceleration / deceleration command including a pattern, a time constant, and a gain. 2. 2. The tapping numerical control device according to claim 1, wherein said control means changes a magnification of a feed speed command of said control axis to an arbitrary speed during reverse feed. Numerical control device for processing.