JPH0688189B2 - Tool change method of automatic tool changer - Google Patents

Description

The present invention relates to a tool changing method for an automatic tool changing device for a machining center. More specifically, the present invention relates to a tool changing method for an automatic tool changing device that can change the tool changing position of the automatic tool changing device according to the height of a workpiece on a table.

[Prior Art] A machining center is known as a machine tool capable of performing a plurality of types of machining such as milling and drilling.
This machining center has a tool magazine that stores tools corresponding to a plurality of types of machining, and directly or indirectly exchanges the tool between the tool and the spindle using a tool exchange arm. Usually, the tool exchange arm is fixed to a fixed position of the machining center body, and when the tool is exchanged, the spindle moves to the fixed position of the tool exchange arm to exchange the tool. In addition, in order to shorten the tool exchange time, a type in which the tool exchange arm follows the vertical movement in synchronization with the vertical movement of the spindle, that is, a spindle following type tool exchange arm has been proposed.

[Problems to be Solved by the Invention] In the method of fixing the tool changing arm at a predetermined position and changing the tool as described above, since the spindle has to move to the changing position every time the tool is changed, the tool is changed for the time required for the movement. There is a drawback that the replacement time becomes long. The method of moving the tool changing arm following the spindle can shorten the tool changing time, but does not take into consideration the circumstances on the side of the work such as the size of the work to be processed. That is, even when there is no need for tool exchange, the tool exchange arm always follows the spindle, so that the tool exchange arm performs a wasteful operation.

Moreover, the spindle follow-up mechanism becomes complicated and causes a failure.
The present invention was made with attention to these problems, and achieves the following objects.

An object of the present invention is to provide a tool changing method for an automatic tool changing apparatus in which the tool changing position of the tool changing arm is changed according to the height of a workpiece to shorten the tool changing time.

Another object of the present invention is to provide a tool changing method for an automatic tool changing apparatus in which the movement of the tool changing arm is suppressed to a necessary minimum.

[Means and Actions for Solving the Problems] The present invention adopts the following means in order to solve the problems and performs the following operations.

a. a body, b. a spindle that moves up and down in the body, c. a tool change arm that moves up and down in a position parallel to the up and down movement to replace a tool mounted on the spindle, d. Arm up-and-down drive means for driving the tool changing arm up and down and stopping only at a plurality of tool changing positions; and e. A tool storage magazine for exchanging tools between the tool changing arm and storing tools. F. A machining center having a workpiece table for mounting and fixing a workpiece to be machined by a tool mounted on the spindle, g. Exchanging the tool between the spindle tool and the tool exchanging arm. A tool changing method for an automatic tool changing apparatus, characterized in that the tool is changed at a selected and predetermined tool changing position by the arm up-and-down driving means according to the height of the workpiece.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective projection view of a machining center for carrying out the tool changing method of the automatic tool changing device of the present invention. Second
The figure is a plan view showing an exchange operation of the twin arm 23.
The machining center 1 is of a type having a horizontal spindle 4. A column 2 is provided on the sliding surface (not shown) of the bed so as to be slidable in the Z-axis direction. On the front of column 2,
A table 3 is arranged, and a workpiece W is placed and fixed on the table 3 for processing.

A main shaft 4 is vertically driven in the column 2 by a Y-axis servomotor (not shown). Two guide surfaces 11 are vertically formed at the corners of the front surface of the column 2.
An upper and lower arm base 12 is provided on the guide surface 11 so as to be vertically movable. A guide surface 13 is provided on the upper and lower arm base 12 in a direction orthogonal to the guide surface 11. Upper and lower arm stand 12
Can be selected from the three positions described below by the upper and lower cylinder device 10. The upper and lower cylinder device 10 is capable of selecting a plurality of linear positions and is known as a step cylinder device.

An arm base 14 is provided on the guide surface 13 so as to be movable (direction of arrow b) by a cylinder device 15. A twin arm 20 is provided on the arm base 14 so as to be swingable (direction of arrow c) around the Y axis (up and down direction). The swing c is swung by the cylinder device 21 around the swing shaft (not shown). When exchanging the old and new tools T, the twin arm 20 is retracted by the rocking cylinder 22 and rotated 180 degrees about itself (arrow d).

The tool storage magazine 30 is arranged on the side surface of the column 2. In the tool storage magazine 30, a large number of tool pots 31 are connected in a chain shape, and indexing and positioning can be performed at a tool replacement position if necessary. The structure of the tool storage magazine 30 is a known structure and will not be described in detail here.

Tool Change Operation FIG. 3 schematically shows the tool change positions corresponding to the heights l ₁ , l ₂ and l ₃ of the workpiece W. For a workpiece W having a relatively low height l ₃ , the twin arm 20 has a low height IIIC.
Change tool at position. Similarly, the workpiece W having an intermediate height l ₂ is the workpiece W with the highest l ₁ at the IIIB position.
Perform tool change operation at position IIIA respectively. The area to be machined, that is, the height mainly varies depending on the height of the work W from the work table 3 and varies.

If the workpiece W is high, various types of machining are performed at the high machining position, and the probability of tool exchange occurring at the high machining position increases. Therefore, exchanging the tool at this position shortens the movement time of the spindle. As a result, the tool change time can be shortened.

Further, the automatic tool changer pulls out the tool from the spindle when changing the tool, and the tip of the tool interferes with the workpiece when the arm rotates. Since this interference area changes depending on the height of the workpiece, the position where the spindle is raised can be set to the minimum height according to the height of the workpiece, and the tool replacement time can be shortened.

Since the height of the work piece is known in advance, it is the predetermined exchange position and the most suitable positions IIIA, IIIB, II.
Change the tool on any of the ICs. Each position of IIIA, IIIB, and IIIC is selectively positioned by the up / down cylinder device 10. FIG. 4 is a flow chart of the operation showing the outline of the replacing operation of the automatic tool changing device. When the machining of the workpiece W is completed and the next new workpiece W is loaded, it is determined whether or not the workpiece W is a new workpiece W (step P ₁ , hereinafter, the step will be omitted).

Next, the upper and lower cylinder device 10 is driven to a position corresponding to the new workpiece W to move the tool changing arm 20 to the corresponding position. That is, as described above, the workpiece having the height l ₁ is located at the position IIIA, the height l ₂ is located at the position IIIB, and the height l ₃ is located at the position II.
Move to IC position. During processing, or processing of the initially determines whether or not it is necessary to tool change (P _3). If there is no need, the next processing operation starts. If a tool change operation is required, the spindle 4 is stopped at the change position selected by the program according to the height of the workpiece W, that is, at any of the A, B, and C positions (P ₄ ).

The cylinder device 15 and the cylinder device 21 operate (combined operation of b and c) to bring the arm base 14 closer to the main shaft 4 side. By this approaching motion, the free tool gripping portion 23 of the twin arm 20 grips the tool T of the spindle 4. The cylinder device 22 operates, the twin arm 23 moves forward, and the tool T in which the spindle 4 is in the unclamped state (clamp mechanism not shown) is extracted (P ₅ ).

The twin arm 23 is inverted (P ₆ ) and again the twin arm 23.
Inserts retracted a new tool T to the spindle 4 (P _7). The new tool T is clamped on the spindle 4. Again, the cylinder device 15 operates and the twin arm 23 retracts by the reverse operation (P ₈ ). It is necessary to change the position of the upper and lower twin arm 23 determines whether (P _9). That is, if the height of the workpiece W is l ₁ , the twin arm 20 is at the position of IIIA, so that the tool T of the tool storage magazine 30 is replaced without changing its position.

When the current position of the twin arm 20 is at the position of IIIB or IIIC, the up / down cylinder device 10 is activated, and the up / down arm base 12 is raised (a operation) to the position of IIIA (P ₁₀ , P ₁₁ ). The twin arm 23 swings, moves straight, and rotates to move to the tool storage magazine 30 side. The arm base 14 moves to the tool storage magazine 30 side (operations b, c, d, P ₁₂ ). Cylinder device 2
2 operates and retracts the twin arm 23, and the old tool T
Insert into pot 31.

Again, the twin arm 20 retracts by the combined operation of b and c, and the twin arm 20 is reversed. At the same time, tool magazine 30
Index a new tool T to the tool change position. The twin arm 20 again moves to the tool storage magazine 30 side by the combined operation of b and c, grabs a new tool T, extracts it from the tool pot 31 by driving the cylinder device 22, and inverts it again by 180 degrees (P ₁₃ ). The upper and lower arm bases 12 are again moved to the positions where the tool exchange operation is performed with the spindle 4, and are positioned at the standby position for the next work W (P ₁₄ , P ₁₅ ).

When the tool T of the spindle 4 is exchanged, the spindle 4 operates simultaneously with the movement of the tool exchanging arm 4 to machine the workpiece W (P ₁₆ ). If it is necessary to change the tool while machining the workpiece W, the process proceeds to step P ₃ . If all processing is complete of the workpiece W (P _17), comprising the processing of the return next new workpiece to step P _1.

[Other Embodiments] The above-described vertical cylinder device 10 can select only three positions, but the present invention is not limited to this. A cylinder device that can be selected in multiple stages of three or more positions may be adopted according to the change in the height of the workpiece. Further, when the height of the workpiece is about two types, a two-position type cylinder device may be used. Further, instead of the up / down cylinder device 10, a servo motor using screw feed may be used so that the selection of the replacement position can be finely selected to an arbitrary multi-step position.

Further, although the above embodiment is a horizontal axis type main axis, it can be applied to a machining center having a vertical type main axis. The twin arm 20 described above is constantly exchanging tools with the tool storage magazine 30 at the IIA position (FIG. 3). However, the structure of the tool storage magazine 30 may be changed and the tools may be replaced at the IIB position, the IIC position, or the like.

[Effects of the Invention] As described in detail above, according to the present invention, the height position of tool exchange between the spindle and the tool exchange arm can be selected according to the height of the workpiece, so that the time for tool exchange can be shortened. It can be effective. It is particularly effective when applied to machining in which high and low workpieces are mixed.

[Brief description of drawings]

FIG. 1 is an oblique projection view of an embodiment of the present invention, FIG. 2 is a plan view of a tool changer, FIG. 3 is a schematic view showing the height of a workpiece and the positional relationship between a spindle and an automatic tool changer, and FIG. The figure is a flowchart showing the outline of the operation of the automatic tool changer. 1 ... Machining center, 2 ... Column, 3 ... Work table, 4 ... Spindle, 10 ... Vertical cylinder device, 12
…… Upper and lower arm stand, 14 …… Arm stand, 23 …… Twin arm, 30 …… Tool storage magazine, 31 …… Tool pot

Claims (1)

[Claims] 1. A machine body, b. A spindle that moves up and down in the machine body, and c. A tool change arm that moves up and down in a position parallel to the up and down movement in order to replace a tool mounted on the spindle. D. Arm up-and-down driving means for driving the tool changing arm up and down and stopping only at a plurality of tool changing positions; and e. For exchanging tools between the tool changing arm and storing tools. A machining center having a tool storage magazine according to f. And a work table on which a work piece to be processed by the tool mounted on the spindle is mounted and fixed, and g. The tool change of the automatic tool changer is performed at the tool change position selected and determined in advance by the arm vertical drive means according to the height of the workpiece. Method.