JP3969664B2 - Numerically controlled machine tool and machining program check method - Google Patents

Description

  The present invention relates to a numerically controlled machine tool such as a 5-axis NC machining center having two rotation axes in addition to three orthogonal axes and a method for checking a machining program.

  In general, when machining a workpiece having a complicated shape such as a fluid machine component or a die, a 5-axis NC machining center that is a numerically controlled machine tool may be used. Such a 5-axis NC machining center is provided with two rotation axes in addition to three orthogonal axes. That is, in the machining center, various cutting tools that are rotatably held on a main shaft through a tool holder and a work held on a rotary table are relatively movable in three axis directions of an X axis, a Y axis, and a Z axis. In addition, a rotary table that holds the workpiece rotatably in the C-axis direction is attached to the rocking plate so as to be rotatable about the A-axis that intersects the C-axis direction (see, for example, Patent Document 1). ).

Such a 5-axis NC machining center may check a machining program by dry run. This method of checking the machining program by dry run is intended by the machining program by executing the machining program command with the tool spaced (offset) from the workpiece by a predetermined distance and confirming the movement of the cutting tool. It is a judgment whether it is a thing.
Japanese Utility Model Publication No. 63-7422

  The conventional 5-axis NC machining center can perform a dry run in a state offset by a predetermined distance from the workpiece with respect to the three directions of the X-axis, Y-axis, and Z-axis, but interlocks with the A-axis and C-axis directions. The cutting tool could not be moved. For this reason, when the work is rotated about the A axis and the C axis, the cutting tool moves irregularly to an arbitrary position with respect to the work, and there is no practical advantage of performing a dry run. For this reason, an operator may actually process a workpiece without performing a dry run. In such a case, an error in cutting the workpiece occurs, which is not economical.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to reliably perform dry run at an arbitrary angular position of a workpiece and perform workpiece cutting at a low cost and easily when performing five-axis cutting. .

The numerically controlled machine tool of the present invention includes a main shaft that holds a cutting tool and a work holding portion that holds a work to be cut by the cutting tool, and the work and the cutting tool are relatively relative to each other in three orthogonal axes. The workpiece holding unit includes a rocking plate that rotates about a first rotation axis, and a rotary table that rotates about a second rotation axis that intersects the first rotation axis. In the numerically controlled machine tool in which the work is held on the rotary table and the cutting tool cuts a plurality of parts of the work by a machining program, the second rotary axis of the rotary table moves the cutting tool relative to the work is along the vertical axis of the offset distance of the second rotational axis direction from the upper surface of the workpiece until the end center of the cutting tool is determined, the swing plate about the first axis of rotation By swinging rotation Te, at any angular position of the second rotational axis when tilted at a predetermined angle with respect to the vertical axis of the workpiece, so as to have the offset distance to the second rotational axis A control device for moving the cutting tool and moving the cutting tool from the offset position to a position corresponding to the cutting depth is provided.

  Note that the fact that the cutting tool can be moved to the machining position at the offset position is a concept including a dry run in which the cutting tool moves as if machining the workpiece and a case where the workpiece is actually cut.

  In the numerically controlled machine tool of the present invention, the cutting tool is offset by a predetermined distance in the second rotation axis direction following the movement of the workpiece, and moves to the machining position at the offset position. The operator can easily confirm the cutting position of the cutting tool with respect to the workpiece.

  Further, when the workpiece is displaced in the second rotational axis direction from the initial setting value, the workpiece is centered on the first rotational axis only by correcting the position of the cutting tool in the second rotational axis direction by the displaced value. Thus, the cutting tool can perform cutting at a predetermined position with respect to the workpiece even if it is rotated to an arbitrary angular position. The operator does not need to correct each position data in the three axis directions orthogonal to each other, the first rotation axis direction, and the second rotation axis direction for each workpiece, and can easily cut the workpiece.

Further, the present invention is a machining program checking method for checking a machining program of a numerically controlled machine tool by dry run, wherein the workpiece is held by a rotary table, and the second rotary axis of the rotary table is set on the cutting tool. Determine the offset distance from the upper surface of the workpiece to the tip center of the cutting tool so that the cutting tool does not contact the workpiece during the dry run after being along the vertical axis that is the moving direction, and the dry mode In response to the above, the rocking plate is swung around the first rotation axis so that the workpiece is tilted by a predetermined angle with respect to the vertical axis, and an arbitrary angular position of the second rotation axis is obtained. in, moving the cutting tool to a position with the offset distance to the second rotational axis, the cutting tool from its offset position Lies in moving to a position corresponding to Kezufuka of.

  The present invention can reliably perform dry run at an arbitrary angular position of the workpiece during five-axis cutting, and can easily and inexpensively cut the workpiece.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 7 show an embodiment of the present invention, and FIG. 1 is a perspective view of a main part of a 5-axis NC machining center as a numerically controlled machine tool. A machining center 1 shown in FIG. 1 includes a spindle head 3 provided perpendicular to a column of a machine tool main body (not shown). The spindle head 3 is provided so as to be movable in two horizontal directions (the X-axis direction and the Y-axis direction) and three vertical directions (Z-axis direction). The spindle head 3 supports a spindle 6 that rotates about the Z-axis direction as a center of rotation. A tool holder 9 that detachably holds various cutting tools 7 is attached to the tip of the spindle 6.

  Below the main shaft 6, both arms 10 a, 10 a are provided with an interval upward and a bed 10 is disposed, and a rocking plate 12 is supported on the bed 10. The rocking plate 12 includes a table support portion 13 and a pair of arm portions 14 and 14 extending from both ends of the table support portion 13. Both arm portions 14 and 14 are supported on both arm portions 10a and 10a of the bed 10 so as to be swingable and rotatable about the A axis direction as a first rotation axis parallel to the X axis direction.

  On the table support portion 13 of the rocking plate 12, a rotary table 15 that rotates about a C axis as a second rotation axis that intersects the A axis is supported. The rotary table 15 is provided with a chuck 18 on which the work 17 is detachably attached. The workpiece 17 can be directly attached to the chuck 18 or can be attached via a workpiece holder (not shown).

  The bed 10, the swinging plate 12, and the rotary table 15 constitute a work holding unit, and the bed 10, the swinging plate 12, the rotary table 15, the spindle head 3, and their drive sources constitute a position adjusting mechanism. ing. The position adjusting mechanism is configured such that the relative positional relationship including the relative angular relationship between the cutting tool 7 attached to the spindle 6 and the workpiece 17 attached to the rotary table 15 is controlled by a control device (not shown) including a computer. It is designed to be numerically controlled.

  Next, a cutting method including a dry run of the 5-axis NC machining center configured as described above will be described. The workpiece 17 has, for example, a rectangular parallelepiped shape, and a drill is provided on the upper surface 17a (see FIG. 4) of the workpiece 17, one side surface 17b (see FIG. 5) of the workpiece 17, and the other side surface 17c (see FIG. 6) of the workpiece 17. The case of cutting each in 7 will be described.

  First, the dry run method will be described. The operator designates the dry run mode from the setting panel or the keyboard, and as shown in FIG. 4A, the C-axis line of the rotary table 15 holding the workpiece 17 is set in the vertical direction (direction along the Z-axis line). Next, an offset distance L from the upper surface 17a of the workpiece 17 to the center of the tip of the drill 7 is determined, and the offset distance L is input to the control device. This offset distance L is a distance at which the drill 7 does not come into contact with the workpiece 17 during the dry run.

  Further, the worker starts a program that has been input to the control device in advance. First, as shown in FIGS. 4A and 4B, when the upper surface 17a of the workpiece 17 is cut vertically, the C-axis is in a vertical state, and the drill 7 attached to the main shaft 15 has a Z-axis. It descends to a predetermined cutting depth h1 along the direction. At this time, since the drill 7 is lowered at the cutting depth h1 at a position offset in the C-axis direction by a predetermined distance L, the cutting depth can be confirmed. In FIG. 4A, 20a indicates a processing hole processed in the workpiece 17.

  Next, as shown in FIGS. 2 and 5 (a) and 5 (b), when the one side surface 17b of the workpiece 17 is cut vertically, the rocking disc 12 rotates 90 degrees around the A axis. At the same time, the drill 7 moves in the X axis direction, the Y axis direction, and the Z axis direction with respect to the workpiece 17. At this time, the drill 7 has an offset distance L in the C-axis direction from the upper surface 17a of the workpiece 17 as described above, and descends to a predetermined lowered position at the offset position. For example, if the actual cutting depth of the processing hole 20b is h2, the drill 7 is lowered to a position corresponding to the cutting depth h2 at the offset position.

  Further, as shown in FIGS. 3 and 6 (a) and 6 (b), when the other side surface 17c of the workpiece 17 is processed obliquely, the rocking plate 12 is swung around the A axis. Thus, the workpiece 17 is inclined by a predetermined angle (α) with respect to the Z axis. Further, the drill 7 has an offset distance L in the C-axis direction from the upper surface 17a of the workpiece 17, and descends from the offset position to a predetermined position. For example, if the distance between the bottom surface of the actual processing hole 20c and the C axis is k1, the drill 7 is lowered to a position where the distance from the C axis is k1 at the offset position. This corresponds to the parallel movement of the drill 7 from the actual cutting position in the C-axis direction.

  Further, when the workpiece 17 is cut at an arbitrary angle on an arbitrary surface of the workpiece 17, even if the posture of the workpiece 17 is changed to an arbitrary angular position, the drill 7 is always offset in the C-axis direction and predetermined from the position. Programmed to descend to position. Therefore, the operator can easily determine whether the machining program is intended by looking at the movement of the machine. Then, after recognizing that the machining program is intended, the machining program is executed, and the workpiece 17 is actually cut by the drill 7. Note that the offset distance L between the drill 7 and the workpiece 17 may be set equal in each cutting step or may be set arbitrarily.

  For example, when the workpiece 17 is displaced in the C axis direction, the machining center can easily correct the displacement and process the workpiece 17 at a predetermined position. That is, suppose that the workpiece 17 itself has a manufacturing error in the C-axis direction, or the workpiece 17 is attached via the workpiece holder so as to be shifted in the C-axis direction compared to the initial setting. For each workpiece 17 to be processed, the operator places each workpiece 17 in the state shown in FIG. 4A, lowers the drill 7, and makes its tip abut against the upper surface 17a of the workpiece 17, thereby causing the Z-axis direction to move. The coordinate position of the upper surface 17a of the workpiece 17 can be confirmed. For example, if the upper surface 17a of the workpiece 17 is shifted by a distance L1 above the initial setting position, the operator inputs data for the shift in the C-axis direction so that the drill 7 processes the distance L1 above. Then, modify the machining program data.

  In this way, when the machining program with the corrected data is executed, as shown in FIG. 7, even if the workpiece 17 is inclined, the drill 7 is offset by a distance L1 in the C-axis direction and cut to a predetermined position. The hole 20d can be cut.

  The present invention is not limited to the embodiment described above. For example, the cutting tool is not limited to a drill but may be an end mill for milling, and the type thereof is not particularly limited. In the case of an end mill, it moves in the cutting direction at the offset position as in the case of cutting. Further, the shape of the workpiece is not limited, and any shape can be adopted.

  As a numerically controlled machine tool, the case where the main shaft 6 side moves in the X-axis direction, the Y-axis direction, and the Z-axis direction has been illustrated, but the work holding unit side may be moved in each axial direction. As long as the configuration moves relative to each other.

It is a perspective view which shows the outline of the 5-axis NC machining center which concerns on this invention. It is a perspective view of the state which made the C axis line horizontal. It is a perspective view of the state which inclined the C axis. The state which made the said C-axis line perpendicular | vertical is shown, (a) is front sectional drawing, (b) is A arrow directional view of (a). The state which made the C-axis horizontal is shown, (a) is front sectional drawing, (b) is B arrow directional view of (a). The state which inclined the C axis line is shown, (a) is front sectional drawing, (b) is C arrow directional view of (a). It is sectional drawing which shows the processing state of the workpiece | work of the state which inclined the C-axis.

Explanation of symbols

6 Spindle 7 Cutting tool 12 Oscillating plate 15 Rotary table 17 Workpiece

Claims (2)

A main shaft for holding a cutting tool and a work holding unit for holding a work to be cut by the cutting tool are provided. The work and the cutting tool are relatively moved in three orthogonal directions, and the work holding unit is provided. Comprises a rocking plate that rotates about a first rotation axis and a rotation table that rotates about a second rotation axis that intersects the first rotation axis, and the work is held on the rotation table, A cutting tool is a numerically controlled machine tool that cuts multiple parts of a workpiece by a machining program.
The second rotation axis of the rotary table is along a vertical axis along which the cutting tool moves relative to the workpiece, and an offset distance in the second rotation axis direction from the upper surface of the workpiece to the tip center of the cutting tool is determined. Then, by swinging and rotating the rocking plate around the first rotation axis, the workpiece is inclined at a predetermined angle with respect to the vertical axis at an arbitrary angular position of the second rotation axis. A control device is provided that moves the cutting tool so as to have the offset distance in the second rotational axis direction, and moves the cutting tool from the offset position to a position corresponding to a cutting depth. Numerically controlled machine tool. A method for checking a machining program for checking a machining program for the numerically controlled machine tool according to claim 1 by dry running,
The workpiece is held by the rotary table, and the cutting tool does not come into contact with the workpiece during the dry run after the second rotary axis of the rotary table is set along the vertical axis that is the moving direction of the cutting tool. Then, an offset distance from the upper surface of the workpiece to the center of the tip of the cutting tool is determined, and the workpiece is moved vertically by swinging and rotating the swing plate around the first rotation axis in accordance with the dry mode. The cutting tool is moved to a position having the offset distance in the second rotation axis direction at an arbitrary angular position of the second rotation axis when tilted by a predetermined angle with respect to the axis, and the cutting tool is moved A method for checking a machining program, wherein the machining program is moved from the offset position to a position corresponding to a cutting depth .

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