JP2005230975A - Method for setting quick feed speed of tool rest in machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the productivity of a machine tool by realizing the reduction of loss time by shortening a quick feed time of a tool rest during machining of a workpiece in a method for setting an acceleration/deceleration speed in quick feed motion of the tool rest in the direction accompanied by the height change like the movement in the X-axis direction of the tool rest of a lathe with a slant type bed. <P>SOLUTION: The acceleration/deceleration characteristic in quick feed motion of the tool rest in the direction accompanied by the height change is divided into four acceleration/deceleration characteristics comprising an acceleration characteristic during moving in the ascending direction of the tool rest, a deceleration characteristic during moving in the ascending direction, an acceleration characteristic during moving in the descending direction, and a deceleration characteristic during moving in the descending direction. The four acceleration/deceleration characteristics are individually set. When an NC device for controlling the machine tool gives a quick feed command to a feed motor of the tool rest accompanied by the vertical movement during moving, it discriminates whether the quick feed direction is the ascending direction or the machining direction. The NC device gives the quick feed command by using setting values of the acceleration characteristic and the deceleration characteristic during moving in the ascending direction when ascending. It gives the quick feed command by using setting values of the acceleration characteristic and the deceleration characteristic during moving in the descending direction when descending. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for setting a rapid feed speed of a tool post in a machine tool. For example, the tool post in a direction with a height change such as movement of the tool post in the X-axis direction in a lathe equipped with a slant type bed. The present invention relates to a method of setting a rapid traverse rate, particularly its acceleration / deceleration rate.

  In order to improve the machining efficiency of a machine tool, it involves the machining of workpieces, such as moving the tool post between the retracted position and the machining position, and moving the tool post from one machining position to the next. There is a demand to move as many blades as possible in as short a time as possible. On the other hand, the turret is generally moved by an NC-controlled feed motor. However, if it is moved at a high speed, the inertia torque during acceleration / deceleration increases, and the maximum rotation speed of the feed motor is limited. Therefore, there is a limit to the rapid feed speed of the tool post.

Therefore, in consideration of the demands for shortening the machining time and the limitations due to the characteristics of the electric motor, the moving speed at the time of rapid feed and the acceleration / deceleration characteristics until the moving speed is reached for each tool post provided on the machine tool. The workpiece is processed by setting. That is, when a fast-forward command is given to the tool post by the machining program, the NC device moves the tool post to the target position according to the set acceleration / deceleration characteristics and moving speed.
Japanese Patent Laid-Open No. 2001-105272

  The setting of the rapid feed speed of the tool post in the conventional machine tool is set in each direction of movement of the tool post, for example, in the case of a general lathe tool post, the Z-axis direction and X in the A portion of the setting screen as shown in FIG. This is done by setting two parameters, a moving speed v and an acceleration / deceleration time t, in each of the axial directions. That is, the moving speed v and the acceleration / deceleration time t in the diagram of FIG. 10 showing the speed of the tool post on the vertical axis and the time on the horizontal axis are set. The NC device controls the fast feed using the same set value t during acceleration and deceleration when the fast feed is commanded.

  An object of the present invention is to reduce the work processing time of a machine tool. As part of this, the productivity of a machine tool is improved by reducing the rapid feed time of the tool post during work processing and reducing the loss time. The challenge is to increase it.

  The rapid feed rate setting method of the tool post in the machine tool of the present application that solves the above problem is a high feed rate setting method of the tool post in the machine tool that sets the movement speed at the rapid feed and the acceleration / deceleration characteristics to the movement speed. Acceleration / deceleration characteristics in rapid traverse of a tool post in a direction with a change in height, acceleration characteristics when moving the tool rest in the upward direction, deceleration characteristics when moving in the upward direction, and acceleration when moving in the downward direction Four acceleration / deceleration characteristics, that is, a characteristic and a deceleration characteristic when moving in the descending direction are individually set. The NC device that controls the machine tool determines whether the rapid feed direction is the ascending direction or the machining direction when giving a rapid feed command to the turret feed motor that moves up and down during movement. The fast-forward command is given using the set value of the deceleration characteristic, and the fast-forward command is given using the set value of the acceleration characteristic and the deceleration characteristic during the downward movement when descending.

  3. The rapid feed speed setting method according to claim 2, wherein the number of set values in the above method is reduced to facilitate the setting operation, and the acceleration / deceleration characteristics in rapid feed of the tool post in the direction accompanied by the height change The heavy load acceleration / deceleration characteristics used when the table is moved up and down and decelerated during the down movement, and the light load acceleration / deceleration characteristics used during acceleration during the down movement and deceleration during the up movement are set.

  When the tool post 3 of a lathe equipped with a slant bed 1 as shown in FIG. The torque acting on the X-axis feed motor of the turret changes due to the gravity acting on the pedestal 3, and further, the inertia accompanying the acceleration / deceleration of the turret 3 acts during acceleration / deceleration.

  In the conventional rapid feed speed setting, the tool post is moved using a constant acceleration / deceleration time t, regardless of the moving direction and acceleration or deceleration. It is necessary to set the acceleration / deceleration time t of the feed motor based on the load torque when the weight of the table and the inertial force act in the same direction, that is, when the torque acting on the feed motor becomes maximum.

  Therefore, in the reverse direction, that is, when the inertial force and gravity due to acceleration / deceleration act in opposite directions (when decelerating during ascending movement and accelerating during descending movement), the motor torque must have sufficient margin. Acceleration / deceleration operation was performed. In other words, at the time of acceleration / deceleration in which acceleration / deceleration inertia and gravity act in opposite directions, the acceleration / deceleration is performed with a motor torque having an extra margin.

  On the other hand, in the present invention, different set values can be used for acceleration / deceleration in which inertia and gravity act in the same direction and acceleration / deceleration in the opposite direction. Therefore, as shown in FIG. 4 and FIG. 8, in the acceleration / deceleration regions t2, t3, and tb where the inertia and gravity act in opposite directions, the tool post can be accelerated and decelerated in a shorter time than before. The moving time of the turret at the set speed v can be lengthened, more rapid rapid feeding can be realized without imposing a burden on the feed motor, the total rapid feeding time can be shortened, and the loss time due to waiting for the turret movement This reduces the machining time.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view of a lathe equipped with a slant bed and upper and lower tool rests. 1 is a bed, 2 is a spindle axis, 3L is a lower tool rest, 4L is an X feed motor for a lower tool rest, 3U Is an upper tool post, 4U is an X feed motor for the upper tool post, and 5U is a Y feed motor for the upper tool post.

  Arrows XL, XU, and YU in the drawing indicate movement directions of the tool rests 3L and 3U in the X direction and the Y direction. In the lathe shown in FIG. 1, the lower tool post 3L moves in a two-dimensional plane in the Z and X directions, and the upper tool post 3U moves in a three-dimensional space in the X, Z, and Y directions. Z is the direction of the axis 2 of the main shaft, X is the cutting feed direction of the cutting tool, and X, Y and Z are directions orthogonal to each other.

  FIG. 2 is a diagram showing an example of a fast-forward speed setting screen in the first embodiment of the present invention. In FIG. 2, A, X, Y, and Z are columns for setting the rapid feed speed in each direction described above, and C is a column for setting the rapid feed speed of the spindle rotation. As shown in the figure, the moving speed v and the acceleration / deceleration time t are set for each of X, Z, C, and Y, and particularly in the X and Y directions, the acceleration time when the tool post is raised. t1 and deceleration time t2, and acceleration time t3 and deceleration time t4 when the tool rest is lowered are set individually.

  FIG. 3 is a diagram showing an example of a flowchart showing a control procedure when the X feed motor 4L of the lower tool post 3L in the lathe of FIG. . When the fast feed is instructed, the X coordinate X1 of the current position is compared with the X coordinate X2 of the target position, and if the two are equal, the operation command is naturally not given to the X feed motor 4L. When X2 and X1 are not equal, the magnitude is compared in step 301. When X2 is smaller than X1, that is, when the lower turret moves upward, the acceleration parameter that determines the acceleration characteristics during rapid traverse is used in the X direction. The acceleration setting value t1 at the time of rising is substituted, and the deceleration setting value t2 at the time of rising in the X direction is substituted for the deceleration parameter for determining the deceleration characteristics (step 302). Conversely, when X2 is larger than X1, the lower tool post 3L moves in the lowering direction of the tool post. Therefore, the acceleration set value t3 for the lowering movement in the X direction is substituted for the acceleration parameter, and X is set in the deceleration parameter. The deceleration set value t4 for the downward movement in the direction is substituted (step 303). Then, using the set moving speed v and the acceleration parameter and the deceleration parameter substituted in the above procedure, the X feed motor 4L is driven to move the lower tool post 3L to the target X coordinate position X2.

  FIGS. 4A and 4B are diagrams showing the operation of the lower tool rest at the time of rapid feed by the above control, in which FIG. 4A is when moving in the upward direction, and FIG. 4B is when moving in the downward direction. As shown in the figure, the acceleration time t1 during acceleration in the upward direction in which the inertial load and gravity act in the same direction is set to be longer than the deceleration time t2 in which the inertial force is in the opposite direction to gravity. Similarly, the acceleration time t3 when the inertial force and gravity work in opposite directions is set smaller than the deceleration time t4 when the inertial force and gravity work in the same direction. Since these set times are set in consideration of the allowable torque of the feed motor 4L,

  The acceleration / deceleration time t in the conventional method shown in FIG. 10 needs to be set in a state where the maximum acceleration / deceleration load is applied to the motor. Therefore, the acceleration / deceleration time t in the conventional method is the same as that in the above embodiment. The time corresponding to the maximum time t1 or t4 in the acceleration time and the deceleration time must be set. That is, in the above embodiment, the deceleration time t2 during the upward movement and the acceleration time t3 during the downward movement in which the inertial force and the weight act in opposite directions are set to a time much shorter than the acceleration / deceleration time t in the conventional method. Accordingly, the rapid movement of the tool post can be performed in a shorter time than the conventional method.

  The flowchart shown in FIG. 3 is for when the lower tool rest 3L is fast-forwarded in the X direction. However, when the upper tool rest 3U is moved in the X direction, the direction approaching the workpiece is the lowering method of the tool rest 3U. The determination conditions in step 301 in FIG. 3 are reversed. Other procedures are the same as those in FIG.

  The upper tool rest 3U of the lathe of FIG. 1 is also movable in the Y direction. Since the upward movement and the downward movement occur even when the upper tool post 3U is fast-forwarded in the Y direction, the movement speed in the Y direction and the acceleration time and deceleration time at the time of upward and downward are individually set on the setting screen of FIG. A control procedure of the Y-axis feed motor using the set value is shown in FIG.

  The flowchart in FIG. 5 is an example in which the upper direction of the Y coordinate is set to the positive direction, and the case where the target coordinate Y2 is larger than the current coordinate Y1 is the upward direction of the tool post. Accordingly, in step 501, when Y2 is larger than Y1, the movement is in the upward direction. Therefore, in the case of ascent, the set values t1 and t2 at the time of ascent are substituted for the acceleration and deceleration parameters in step 502. Substituting the set values t3 and t4 at the time of descent into, fast-forwarding is performed.

  FIGS. 6 to 8 are diagrams showing a second embodiment of the present invention, in which the acceleration setting value at the time when the gravity of the tool post and acceleration / deceleration inertia work in the same direction and the deceleration setting value at the time of lowering are the same values ( This is an example in which the same value (light inertia set value) is used for the ascending direction deceleration value and the descending direction acceleration value in which the gravity of the tool post and the acceleration / deceleration inertia force work in opposite directions. In this case, the setting fields for the X and Y directions on the acceleration / deceleration parameter setting screen include 3 each of a moving speed v, a heavy inertia setting value ta, and a light inertia setting value tb, as shown in part A of FIG. One by one.

  FIG. 7 is a flowchart showing the fast-forward control procedure of the lower X-feed motor 4L in the second embodiment. In the same manner as in FIG. 3, it is determined whether the tool post is moved up or down in step 701. In the case of ascent, the turret weight and acceleration inertia work in the same direction during acceleration, and the turret weight and deceleration inertia work in opposite directions during deceleration, so the X-direction heavy inertia set value ta is set as the acceleration parameter. Substitute, and the X direction light inertia set value tb is substituted for the deceleration parameter (step 702). In the case of descent, the reverse is true, as shown in step 703. Thereafter, fast-forwarding is performed up to the target coordinate X2.

  FIG. 8 is a feed diagram of the tool rest according to the second embodiment, where (a) is for the upward movement and (b) is for the downward movement. As shown in the figure, during acceleration in the upward direction and deceleration in the downward direction where a large load is applied to the feed motor, acceleration / deceleration is performed with the same acceleration / deceleration time ta as in the past, and during acceleration in the upward direction and acceleration in the downward direction with a small load. Acceleration / deceleration is performed in a shorter time tb than in the prior art. Therefore, the time required for rapid feed of the tool post can be shortened, and the machining time of the workpiece as a whole can be shortened.

Schematic diagram showing X movement and Y movement of the tool post of a lathe equipped with a slant bed and upper and lower tool post The figure which shows an example of the setting screen of a 1st embodiment The flowchart which shows the rapid feed control of the lower tool post X feed motor of the 1st embodiment. Operating diagram of turret when fast-forwarding and lowering Flowchart showing the fast feed control of the upper tool post Y feed motor of the first embodiment. The figure which shows an example of the setting screen of a 2nd embodiment The flowchart which shows the rapid feed control of the lower tool post X feed motor of the 2nd embodiment. Operation diagram of the tool post of the second embodiment at the time of rapid traverse rising and lowering An example of a conventional setting screen Operation diagram for conventional tool post when fast-forwarding and lowering

Explanation of symbols

1 Bed 2 Spindle axis 3 Tool post 4 X feed motor 5 Y feed motor

Claims (2)

In the rapid feed speed setting method of the tool post in the machine tool that sets the movement speed at rapid traverse and acceleration / deceleration characteristics to the movement speed,
Acceleration / deceleration characteristics in rapid traverse of the tool post in the direction with height change, acceleration characteristics and deceleration characteristics during the upward movement of the tool rest, and acceleration characteristics and deceleration characteristics during the downward movement A rapid feed speed setting method for a tool post in a machine tool. In the rapid feed speed setting method of the tool post in the machine tool that sets the movement speed at rapid traverse and acceleration / deceleration characteristics to the movement speed,
Acceleration / deceleration characteristics in rapid traverse of the tool post in the direction with height change, heavy load acceleration / deceleration characteristics used for acceleration of the upward movement of the tool rest and deceleration of the downward movement, and deceleration of acceleration of the downward movement and deceleration of the upward movement A method for setting a rapid feed rate of a tool post in a machine tool, characterized by setting a light load acceleration / deceleration characteristic used sometimes.

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