JP2013210926A - Groove forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately form a groove on a curved surface of a work while using a 5-axis NC machine tool which cannot simultaneously perform 2-axis control for changing a rotation axis of the machine tool and 3-axis control for relatively moving the machine tool.SOLUTION: A curved surface 30 is divided into a plurality of divided surfaces 31 in a predetermined dividing position 32. The divided surfaces 31 are cut by a machine tool 10 in which a direction and an angle of a rotation axis 12 are adjusted. On the divided surface 31, a groove 22 is formed by the machine tool 10. In the dividing position 32, the machine tool 10 is separated from a work 20 and the formation of the groove 22 is intercepted. The direction and the angle of the rotation axis 12 of the machine tool 10 separated from the work 20 are changed in accordance with the divided surface 31 to be cut next. The machine tool 10 is returned to the dividing position 32, and the formation of the groove 22 is resumed.

Description

  The present invention relates to a groove forming method for forming a groove on a curved surface of a workpiece by a machine tool.

  Numerically controlled machine tools (NC (Numerically Controlled) machine tools) are used to perform various types of processing on workpieces. The NC machine tool moves the tool relative to the workpiece by numerical control. Conventionally, as this NC machine tool, a three-axis NC machine tool for moving a tool in three orthogonal directions is known (see Patent Document 1).

FIG. 7 is a diagram illustrating an example in which the workpiece 110 is machined by the three-axis NC machine tool 100. FIG. 7 shows a cross section of the workpiece 110 and the tool 101 of the three-axis NC machine tool 100.
The 3-axis NC machine tool 100 processes the workpiece 110 into a target shape with the moving tool 101. However, in the 3-axis NC machine tool 100, the direction of the tool 101 is fixed, and the direction and angle of the tool 101 cannot be changed. Therefore, when forming the groove | channel 111 in the workpiece | work 110, it is necessary to make the process surface 112 of the workpiece | work 110 horizontal (refer FIG. 7A). On the other hand, when the processing surface 112 is a curved surface or an inclined surface (see FIG. 7B), the groove 111 perpendicular to the processing surface 112 cannot be formed.

  Thus, in the conventional triaxial NC machine tool 100, the shape of the groove 111 may be limited. In particular, when the grooves 111 are formed on a curved surface or a curved inclined surface, the grooves 111 cannot be formed in a target shape, and the grooves 111 may not be connected to each other. Therefore, in the 3-axis NC machine tool 100, it is difficult to accurately form the groove 111 on the curved surface of the workpiece 110.

JP-A-8-249036

  The present invention has been made in view of the above-described conventional problems, and its purpose is a 5-axis NC that cannot simultaneously perform 2-axis control for changing the rotation axis of the tool and 3-axis control for relatively moving the tool. It is to accurately form a groove on a curved surface of a workpiece by a machine tool.

  The present invention is a 5-axis NC machine that cannot simultaneously perform 2-axis control for changing the direction and angle of the rotation axis of the tool and 3-axis control for moving the tool in the 3-axis direction orthogonal to the workpiece. A groove forming method for forming a groove on a curved surface of a workpiece by a machine, wherein a plurality of divided surfaces obtained by dividing the curved surface at a predetermined division position are cut by a tool whose direction and angle of the rotation axis are adjusted. Forming process for forming a groove on the dividing surface, Interrupting process for separating the tool from the workpiece at the dividing position and interrupting the groove formation, Dividing to next cut the direction and angle of the rotation axis of the tool separated from the work The groove forming method includes a changing step that changes in accordance with a surface, and a resuming step that returns the tool to the division position and resumes the formation of the groove.

  According to the present invention, a 5-axis NC machine tool that cannot simultaneously perform 2-axis control for changing the rotation axis of a tool and 3-axis control for relatively moving a tool can accurately form a groove on a curved surface of a workpiece. Can be formed.

It is a perspective view which shows the NC machine tool of this embodiment. It is the top view which looked at the work from the upper part. It is a figure which shows the tool which forms a groove | channel in the inclined surface of a workpiece | work. It is a figure which shows the tool which forms a groove | channel in the curved surface of a workpiece | work. It is a figure which shows the tool which adjusts a rotating shaft. It is a figure which shows the tool in forming the groove | channel. It is a figure which shows the example which processes a workpiece | work with a 3-axis NC machine tool.

An embodiment of the groove forming method of the present invention will be described with reference to the drawings.
In the groove forming method of the present embodiment, a groove is formed in a workpiece by an NC machine tool. Hereinafter, the case where the workpiece is a mold for molding a foamed resin will be described as an example.

  The workpiece is an object to be processed by the NC machine tool (processing object). The foamed resin is a foamable resin and is injected into the mold. The foamed resin is foamed in a mold and molded into a predetermined shape. For example, a vehicle seat pad is molded from the foamed resin. The vehicle seat pad is a pad provided in a seat of a vehicle such as an automobile. A seat pad is formed by a mold for the seat pad.

FIG. 1 is a perspective view showing an NC machine tool 1 of the present embodiment. FIG. 1 shows a schematic configuration of the NC machine tool 1.
The NC machine tool 1 of this embodiment is a 5-axis NC machine tool. The NC machine tool 1 includes a pair of columns 2, a cross rail 3, a table 4, a saddle 5, a ram 6, a spindle head 7, and a spindle 8 as shown in the figure. Both ends of the cross rail 3 are attached to a pair of columns 2. The table 4 is movably installed between the pair of columns 2. The saddle 5 is movably attached to the cross rail 3. The ram 6 is movably supported by the saddle 5. The spindle head 7 is pivotally attached to the tip of the ram 6. The main shaft 8 is connected to the main shaft head 7 via a drive shaft 8A.

  The NC machine tool 1 includes a control device 9, a tool 10, and a drive device (not shown). The control device 9 controls the entire NC machine tool 1. The tool 10 is attached to the main shaft 8 and rotates together with the main shaft 8. The drive device includes, for example, a motor and an operation mechanism (such as a feed mechanism) that operates the movable portion by the power of the motor. NC machine tool 1 drives a plurality of movable parts by a drive device. The table 4 moves in the X-axis direction (front-rear direction) within a horizontal plane. The saddle 5 is guided by the cross rail 3 and moves in the Y-axis direction (left-right direction). The ram 6 moves in the Z-axis direction (vertical direction) while being supported by the saddle 5. The spindle head 7 turns in the C-axis direction at the tip of the ram 6. The main shaft 8 rotates in the A-axis direction around the drive shaft 8A. The main shaft 8 rotates around the rotation axis.

  The tool 10 is a rotary processing tool (for example, an end mill) for cutting the workpiece 20 to form a groove in the workpiece 20. The tool 10 rotates around the rotation axis by the rotation of the main shaft 8. The workpiece 20 is fixed to the upper surface of the table 4. The NC machine tool 1 cuts the workpiece 20 with a rotating tool 10. At that time, the table 10, the saddle 5, and the ram 6 are moved so that the tool 10 is relatively moved in three axial directions (X, Y, and Z axis directions) orthogonal to the workpiece 20. A groove is formed in the workpiece 20 by the tool 10 that rotates and relatively moves. Further, the tool 10 is rotated in two axial directions (A and C axis directions) by turning the spindle head 7 and rotating the spindle 8. The direction and angle of the rotation axis of the tool 10 are changed by the biaxial rotation.

  The 5-axis NC machine tool 1 according to the present embodiment cannot simultaneously control the rotation in the two-axis direction and the relative movement in the three-axis direction. That is, the NC machine tool 1 cannot perform two-axis (two-axis direction) control and three-axis (three-axis direction) control simultaneously, and performs each control separately. The biaxial control is control of two axes (A axis and C axis) for changing the direction and angle of the rotation axis of the tool 10. The three-axis control is control of three axes (X axis, Y axis, Z axis) for moving the tool 10 in the three axis directions orthogonal to the workpiece 20. The NC machine tool 1 stops the control of the two axes to control the three axes, stops the control of the three axes, and controls the two axes. Hereinafter, a groove forming method for forming a continuous groove on the curved surface of the workpiece 20 by the NC machine tool 1 will be described. The NC machine tool 1 forms a groove in the workpiece 20 by cutting the workpiece 20 with the tool 10.

FIG. 2 is a plan view of the workpiece 20 as viewed from above.
The work 20 has a belt-like inclined surface 21 as illustrated. The inclined surface 21 is a surface inclined with respect to a horizontal plane (XY plane). The inclined surface 21 is formed in a rectangular shape with a predetermined width. The inclined surface 21 is formed endlessly on the upper surface of the workpiece 20. A part of the inclined surface 21 is a curved surface 30. The four corners of the inclined surface 21 are curved. An endless groove 22 (indicated by a dotted line in FIG. 2) is formed on the inclined surface 21 and the curved surface 30 by the tool 10 of the NC machine tool 1. Here, a groove 22 in which a mold seal member is disposed is formed in the inclined surface 21 and the curved surface 30 of the workpiece 20.

FIG. 3 is a view showing the tool 10 that forms the groove 22 in the inclined surface 21 of the workpiece 20. In FIG. 3, the workpiece | work 20 cut | disconnected by the FF line of FIG. 2 is shown.
The tool 10 of the present embodiment is a ball end mill in which a tip portion 11 is formed in a spherical shape as shown in the figure. The workpiece 20 is cut by a blade (not shown) provided on the tool 10 (including the tip portion 11).

  When cutting the inclined surface 21 other than the curved surface 30, the rotary shaft 12 of the tool 10 is inclined according to the inclined surface 21. The direction and angle of the rotating shaft 12 are changed corresponding to the inclined surface 21. At that time, the direction and angle of the rotary shaft 12 are adjusted so that the rotary shaft 12 is perpendicular to the inclined surface 21. The inclined surface 21 is cut by the tool 10 with the rotating shaft 12 adjusted, and a groove 22 is formed in the inclined surface 21. The NC machine tool 1 causes the tool 10 to move relative to the extending direction of the inclined surface 21 to continuously form the groove 22 on the inclined surface 21. The groove 22 is formed perpendicular to the inclined surface 21.

FIG. 4 is a diagram illustrating the tool 10 that forms the groove 22 in the curved surface 30 of the workpiece 20. 4 schematically shows the curved surface 30 viewed from the G direction in FIG. The groove 22 is indicated by a dotted line through the workpiece 20. In FIG. 4, the formed groove 22 is virtually shown. In practice, the groove 22 is gradually formed by the movement of the tool 10.
The curved surface 30 is a surface to be machined of the workpiece 20 as illustrated. Here, the curved surface 30 is a curved inclined surface 21 formed on the inclined surface 21 of the workpiece 20. The curved surface 30 is curved and inclined.

  When processing the curved surface 30, the curved surface 30 is divided into a plurality of divided surfaces 31. The divided surface 31 is a divided curved surface obtained by dividing the curved surface 30 of the workpiece 20 at a predetermined division position (divided portion) 32. The division position 32 is set at a predetermined position on the groove forming path of the curved surface 30. Therefore, the division position 32 is also the division position of the groove 22. At least one division position 32 is set on the curved surface 30. The plurality of divided surfaces 31 are cut by the tool 10 whose direction and angle of the rotary shaft 12 are adjusted. The grooves 10 (divided grooves) are sequentially formed on the plurality of dividing surfaces 31 by the tool 10.

  Here, the curved surface 30 is divided into two divided surfaces 31 </ b> A and 31 </ b> B by one divided position 32. Further, the relative movement of the tool 10 is stopped at the division position 32, and the direction and angle of the rotary shaft 12 of the tool 10 are adjusted. The direction and angle of the rotating shaft 12 are adjusted corresponding to each of the dividing surfaces 31A and 31B. The split surfaces 31A and 31B are cut with the tools 10A and 10B each having a fixed direction and angle of the rotary shaft 12, respectively. By forming the grooves 22 in order on the plurality of divided surfaces 31 </ b> A and 31 </ b> B, the grooves 22 continuous with the curved surface 30 are formed.

FIG. 5 is a view showing the tool 10 for adjusting the rotating shaft 12.
As illustrated, the tool 10A moves toward the dividing position 32 while cutting the dividing surface 31A. A groove 22 is formed in the dividing surface 31A. When the tool 10A reaches the dividing position 32, the tool 10A is pulled up from the workpiece 20. Thereby, the tool 10 </ b> A is once separated from the workpiece 20 at the division position 32. The cutting of the curved surface 30 by the tool 10 and the formation of the groove 22 are interrupted. Subsequently, the direction and the angle of the rotary shaft 12 of the tool 10A separated from the workpiece 20 are changed corresponding to the divided surface 31B to be cut next. The direction and angle of the rotating shaft 12 are changed according to the direction and angle of the dividing surface 31B, for example. Thereby, the direction and angle of the rotating shaft 12 of the tool 10B are adjusted.

  Next, the tool 10 </ b> B whose direction and angle of the rotary shaft 12 are changed is re-entered into the division position 32. The tool 10B is returned to the workpiece 20 at the division position 32, and cutting of the next division surface 31B is started. The cutting of the curved surface 30 by the tool 10 and the formation of the groove 22 are resumed. The grooves 22 of the dividing surfaces 31 </ b> A and 31 </ b> B are connected at the dividing position 32. The tool 10B moves away from the division position 32 while cutting the next division surface 31B. By connecting the grooves 22 of the plurality of divided surfaces 31 </ b> A and 31 </ b> B, the groove 22 in which the seal member is disposed is formed on the curved surface 30 of the workpiece 20.

  When the direction and angle of the rotating shaft 12 are changed at the division position 32, the tool 10B after the change is brought closer to the perpendicular to the curved surface 30 at the division position 32 than the tool 10A before the change. That is, the angle between the rotation axis 12 (tool 10B) after the change and the normal line L is made smaller than the angle between the rotation axis 12 (tool 10A) before the change and the normal line L. The normal line L is a normal line of the curved surface 30 at the division position 32. As a result, the tool 10B is brought into a state close to perpendicular to the curved surface 30 at the division position 32. With the tool 10 returned to the dividing position 32, the groove 22 is accurately formed on the next dividing surface 31B.

  When the formation of the groove 22 is resumed at the division position 32, the movement direction D of the tool 10B returned to the division position 32 is matched with the movement direction U of the tool 10A separated from the workpiece 20 at the division position 32. At that time, the angle between the moving direction D of the tool 10B and the moving direction U of the tool 10A is adjusted to a predetermined angle (here, 0 to 5 °). That is, the moving direction D of the tool 10B is made to coincide with the moving direction U of the tool 10A. Alternatively, the angle between the moving direction D of the tool 10B and the moving direction U of the tool 10A is set to 5 ° or less. In this state, the tool 10B is moved in the movement direction D and returned to the division position 32. The tool 10B cuts the curved surface 30 while moving along the movement path of the tool 10A. By cutting in this way, the grooves 22 of the adjacent divided surfaces 31A and 31B are reliably connected. Further, the groove 22 at the division position 32 is formed with high accuracy.

FIG. 6 is a view showing the tool 10 in which the groove 22 is being formed.
The tool 10 moves toward the start position S of the curved surface 30 while cutting the inclined surface 21 as shown in the figure. When the cutting of the curved surface 30 is started, the tool 10 is separated from the workpiece 20 at the start position S of the curved surface 30. The rotary shaft 12 of the tool 10 is adjusted in correspondence with the first dividing surface 31 </ b> A, similarly to the dividing position 32. The dividing surface 31A is cut with the tool 10A to form the grooves 22 in the dividing surface 31A. When the cutting of the curved surface 30 is finished, the tool 10B is separated from the workpiece 20 at the end position E of the curved surface 30. The rotary shaft 12 of the tool 10B is adjusted corresponding to the inclined surface 21 to be cut next, similarly to the division position 32. The inclined surface 21 is cut by the tool 10 to form a groove 22 in the inclined surface 21. The inclined surface 21 and the groove 22 of the dividing surface 31 are connected to form a continuous groove 22 on the inclined surface 21 and the curved surface 30.

  When the workpiece 20 is cut, the relative movement of the tool 10 is controlled with reference to the spherical tip portion 11 of the tool 10. At that time, a line passing through the center of the tip end portion 11 is used as a machining line K of the workpiece 20. The center of the distal end portion 11 is moved along the machining line K set on the workpiece 20. Thereby, the groove 22 is formed with high accuracy. Further, the depth of the groove 22 is kept constant.

  The curved surface 30 is divided corresponding to a predetermined division condition. The division conditions are, for example, the shape of the curved surface 30, the shape of the groove 22, and the shape of the tool 10. The division position 32 is set to a predetermined position on the groove forming path of the curved surface 30 corresponding to the division condition. The curved surface 30 is divided at the dividing position 32 so that each divided surface 31 is close to a flat surface. One or a plurality of division positions 32 are set on the curved surface 30. Each of the curved surfaces 30 is divided into two or more.

  The direction and angle of the rotary shaft 12 of the tool 10 are set corresponding to the formation conditions of the predetermined groove 22. The formation conditions are, for example, the shape of the groove 22, the direction of the groove 22, the angle of the groove 22, the shape of the dividing surface 31, the direction of the dividing surface 31, the angle of the dividing surface 31, and the shape of the tool 10. The direction and angle of the rotating shaft 12 are changed and adjusted according to the formation conditions of the groove 22. The direction and angle of the rotating shaft 12 are set so that the target shape of the groove 22 and the actual shape of the groove 22 are approximated.

  The division position 32 of the curved surface 30, the movement path of the tool 10, the direction of the rotary shaft 12, and the angle of the rotary shaft 12 are preset in the control device 9. NC data (NC program) for the NC machine tool 1 is created and input to the control device 9 in advance. The control device 9 controls the NC machine tool 1 based on the NC data. The NC machine tool 1 forms a groove 22 in the workpiece 20 based on the NC data.

  As described above, in the groove forming method of the present embodiment, the plurality of divided surfaces 31 obtained by dividing the curved surface 30 are cut by the tool 10 whose direction and angle of the rotary shaft 12 are adjusted. Therefore, the groove 22 can be accurately formed in the curved surface 30 of the workpiece 20. Moreover, the precision of the shape and dimension of the groove | channel 22 can be improved. Even when the curved surface 30 is the curved inclined surface 21, the groove 22 can be formed with high accuracy.

  In addition, if it is NC machine tool (it is called simultaneous control machine) which can control 5 axes | shafts simultaneously, the groove | channel 22 can be formed continuously. However, such a simultaneous controller is expensive. Moreover, it is difficult for the simultaneous controller to accurately process a large workpiece 20 (for example, 1 m × 1 m or more). On the other hand, in the present embodiment, the groove 22 can be accurately formed in the large workpiece 20 by the simple and inexpensive NC machine tool 1. Even for a smaller workpiece 20, the groove 22 can be formed with high accuracy close to that of the simultaneous controller.

  Two or more division positions 32 may be set on the curved surface 30. In this case, the curved surface 30 is divided into three or more divided surfaces 31. The groove 22 may be formed in a straight line or may be formed in a curved shape by being curved. When the curved groove 22 is formed on the processing target surface (the curved surface 30 or the curved inclined surface 21), the division position 32 is set on the processing target surface corresponding to the curve of the groove 22. The groove 22 is divided into a plurality at the division position 32. The groove 22 of the dividing surface 31 is formed in order, and the curved groove 22 is formed.

  The groove 22 of the dividing surface 31 is formed by cutting once with the tool 10. However, the groove 22 may be formed by cutting a plurality of times in the width direction or the depth direction. The tool 10 may be a tool capable of forming the groove 22 other than the end mill. When the tool 10 is an end mill, various end mills can be used.

  DESCRIPTION OF SYMBOLS 1 ... NC machine tool, 2 ... Column, 3 ... Cross rail, 4 ... Table, 5 ... Saddle, 6 ... Ram, 7 ... Spindle head, 8 ... Main shaft, 8A ... drive shaft, 9 ... control device, 10 ... tool, 11 ... tip, 12 ... rotary shaft, 20 ... workpiece, 21 ... slope, 22 ... Groove, 30 ... curved surface, 31 ... divided surface, 32 ... divided position, L ... normal.

Claims (6)

A 5-axis NC machine tool that cannot simultaneously control 2-axis control to change the direction and angle of the tool rotation axis and 3-axis control to move the tool in the 3-axis direction orthogonal to the workpiece. A groove forming method for forming a groove on the curved surface of
Forming a groove on the divided surface by cutting a plurality of divided surfaces obtained by dividing the curved surface at a predetermined dividing position with a tool that adjusts the direction and angle of the rotation axis;
An interruption process in which the tool is separated from the workpiece at the dividing position to interrupt the groove formation;
A change step of changing the direction and angle of the rotation axis of the tool separated from the workpiece corresponding to the divided surface to be cut next;
A resuming step of returning the tool to the split position and restarting the groove formation;
A groove forming method comprising: In the groove | channel formation method described in Claim 1,
The step of changing the angle between the rotation axis after the change and the normal of the curved surface at the division position is smaller than the angle between the rotation axis before the change and the normal of the curved surface at the division position. A groove forming method comprising: In the groove forming method according to claim 1 or 2,
The resuming step makes the tool movement direction coincide with the tool movement direction of the interruption step, or sets the angle between the tool movement direction and the tool movement direction of the interruption step to 5 ° or less, and A groove forming method including a step of returning to a divided position. In the groove forming method according to any one of claims 1 to 3,
A groove forming method in which the curved surface of the workpiece is a curved inclined surface formed on the inclined surface of the workpiece. In the groove | channel formation method as described in any one of Claim 1 thru | or 4,
A groove forming method in which the workpiece is a mold for molding a foamed resin. In the groove | channel formation method described in Claim 5,
A groove forming method in which a groove formed in a workpiece is a groove in which a mold seal member is disposed.

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