JP4276103B2 - Handling method of spindle tool in machine tool - Google Patents

Description

  The present invention relates to a method for handling a spindle tool applied to a machine tool such as a machining center.

  Conventionally, as the name suggests, an armless automatic tool changer is capable of holding a tool without using a special arm for an automatic tool changer (ATC) when changing tools, which is an important function of a machining center. This is a device in which the main spindle can be taken in and out directly from the tool drum. In this case, the unclamping (clamping) operation of the tool is performed by the draw bar incorporated in the main shaft, and the taper of the main shaft and the tool is surely secured by using a tap allowance of 0.5 mm to 0.8 mm. Has the function of separating.

  An example of the tool change by the armless automatic tool changer is shown in FIG. FIG. 3 is a front view schematically showing a part of the armless automatic tool change and showing its operation mode step by step. FIG. 3A is a diagram showing a state in which the spindle holding the spindle tool is returned to the tool return position. The spindle tool 10 is supported at predetermined intervals on the peripheral edge of the tool drum 21 of the tool magazine 20, and only a part (two spindle tools 10 and 11) is shown in the figure. The tapered portion 12 formed on the spindle tool 10 is designed to have the same structure for all the tools to be handled. When the tapered portion 12 is supported by the peripheral portion of the tool drum 21, the tapered portion 12 is directed upward.

  The main shaft 1 is rotatably supported by an appropriate bearing in the main shaft sleeve 2, and a tapered hole 3 capable of accommodating the tapered portion 12 of the main shaft tool is formed at the tip portion. The main shaft 1 is movable in the horizontal direction between a tool change position occupied in the figure and a machining position (not shown). The spindle 1 is also moved up and down in the vertical direction to separate and grip the spindle tool as shown in the tool change position, and to move the held spindle tool closer to and away from the workpiece at the machining position. You can also The tapered hole 3 of the spindle 1 receives the tapered portion 12 of the spindle tool 10, and the spindle tool 10 is coupled to a drawper shaft (not shown) and clamped in a state of being biased upward by a spring or the like.

  As shown in FIG. 3A, at the tool change position, the spindle tool 10 is returned to a predetermined return position by lowering the spindle 1. The spindle tool 10 is separated from the tapered hole 3 of the spindle 1 by releasing the connection with the drawper shaft and performing a simple unclamping operation or hitting the spindle 1 with an appropriate means. As shown in FIG. 3B, the spindle 1 from which the spindle tool 10 is separated rises at the tip of the spindle 1 to be higher than the height of the tapered portion 12 of the spindle tool 10. Next, as shown in FIG. 3C, the tool magazine 20 is rotated (shifted in the horizontal direction in the figure) until the spindle tool 11 to be gripped next coincides with the axis of the raising / lowering position of the spindle 1. Be transported. Finally, as shown in FIG. 3D, the spindle 1 descends and grips the next spindle tool 11.

  The 7/24 taper, which is widely used as a machining tool for machining centers, does not self-lock like the Morse taper. For example, in the case of vertical and horizontal machining centers, the tool is normally unclamped. In this case, the tool can fall freely from the spindle. However, it is known that in a current machine tool, a phenomenon in which the tool bites the spindle taper irregularly occurs at an extremely rare frequency of thousands to tens of thousands of times. When such a biting phenomenon occurs, even when trying to unclamp the tool, it does not fall naturally, and even if the tool is struck, it cannot be detached from the spindle. In such a situation, since the execution of the predetermined ATC is hindered, there is a problem that the parts related to the tool changer such as the tool gripper and the tool drum are damaged.

  This phenomenon of disengagement of the tool occurs when the machine tool is stopped during a break such as lunch break immediately after the spindle tool is used for continuous machining of the workpiece, and the spindle operation is stopped for more than 10 minutes. It is also well known. From this, the cause of this biting phenomenon is that the heat generated in the spindle bearing by continuous machining of the workpiece enlarges the taper hole of the spindle, and the spindle tool is drawn into the taper hole along the taper by the enlarged amount. Then, it is considered that the operation of the main shaft is stopped and the main shaft taper portion contracts due to the forced cooling of the main shaft, and the contraction strongly holds the tool.

  In a machine tool, a spindle device has been proposed in which a simple mechanism is added to a hammer device for removing a tool so that a tool stuck on the spindle can be easily extracted (see Patent Document 1). In this spindle device, fluid pressure driving members such as first and second pistons that enable the spindle to be pushed out to the tip end side are provided, and the detection member detects the push-out state of the hammer shaft to detect the spindle of the tool. When the bite is detected, the hammer shaft pushed out by the first piston is knocked out toward the tip end side of the main shaft by the second piston, so that the bite of the tool is released.

  In a tool machine with an ATC equipped with a swivelable exchange arm, the tool biting device with biting tool designed to reduce the number of alarm stops by automatically hitting and pulling the tool biting into the taper hole of the spindle several times. Has been proposed (see Patent Document 2). According to this biting tool extraction device, when the tool is biting into the taper hole of the main shaft, the movement of the exchange arm in the pivot axis direction is prevented for more than the set time. An operation retry command is issued, and tool clamping / unclamping is repeated a set number of times to release the biting tool from the taper hole of the spindle.

  A tool extraction device with bite that prevents the ATC from becoming impossible due to the tool biting into the main spindle taper hole and stopping the machine has been proposed (see Patent Document 3). According to this proposal, when the tool bites into the spindle taper hole due to long-time powerful cutting, etc., and it can no longer be pulled out by the tool change arm, the sampling time comparison unit detects the delay and keeps the hammer motor constant. It is driven for a long time and the tool bite is struck with a hammer to loosen the tool. When the tool does not loosen by this operation, the hammering is repeated a predetermined number of times, and when the tool still does not loosen, the machine is stopped.

There has been proposed a cam type tool changer which is designed to accurately detect problems such as cam wear by comparing the load of the cam drive motor with the limit load set for each operation of the tool change arm ( Patent Document 4). The cam shaft driven by the cam drive motor is provided with a first cam that converts rotational motion into a plurality of stages of rotational motion, and a second cam that converts rotational motion into reciprocating motion. The movement of the first follower driven by the second follower and the second follower driven by the second cam is transmitted to the tool changing arm via the motion transmission mechanism. A swivel motion and a reciprocating linear motion are given to the tool change arm, and tool change is performed between the spindle and the tool change position. When the load on the cam drive motor exceeds the limit load, a warning signal is output or the drive motor is stopped.
Japanese Unexamined Patent Publication No. 2000-94255 (paragraphs [0010] to [0011], FIGS. 1, 2 and 4) Japanese Utility Model Laid-Open No. 5-80638 (paragraphs [0010] to [0011], FIG. 1) Japanese Utility Model Publication No. 5-72342 (paragraphs [0010] to [0011], FIGS. 3 and 5) Japanese Patent Laid-Open No. 2001-232532 (paragraphs [0010] to [0011], FIGS. 1, 2, and 4)

  Thus, in a machine tool that processes a workpiece with a spindle tool, it is important that the spindle tool is reliably removed from the spindle. Therefore, in a machine tool including a driven spindle and a spindle tool for machining a workpiece attached to the spindle, the spindle is caused to leave the spindle temperature drop while the spindle tool is stuck. Thus, there is a problem to be solved in order to avoid a situation where it is difficult to remove the spindle tool.

  The object of the present invention is that when the operation of the spindle of the machine tool is stopped for a certain period or more, such as during a lunch break, the spindle tool is firmly held by the spindle due to a decrease in the temperature of the spindle. , It is possible to prevent the removal of the spindle tool from the spindle, to ensure the execution of ATC, and to prevent the parts related to the tool changer such as the tool gripper and the tool drum from being damaged. It is to provide a method for handling a spindle tool.

  In order to solve the above-described problems, a spindle tool handling method according to the present invention is a machine tool including an operating spindle and a spindle tool for machining a workpiece attached to the spindle, and the operation of the spindle is stopped. The spindle tool is removed from the spindle in response to the passage of a predetermined time.

  According to this method for handling a spindle tool, when the operation of the spindle provided in the machine tool is stopped and a predetermined time has elapsed after the stop, the spindle tool is removed from the spindle in response to the progress. The temperature of the spindle spindle that has risen during operation of the spindle starts to decrease after the operation is stopped, but if the operation stop time of the spindle exceeds a predetermined time, the main spindle tool is urgently escaped in response to the elapse of the predetermined time. Is removed from the main shaft, so that the main shaft and the joint portion such as the tapered portion of the tool do not bite to the extent that separation due to thermal contraction becomes difficult.

  In this spindle tool handling method, the machine tool includes a tool magazine capable of individually accommodating a plurality of spindle tools, and the spindle tool removed from the spindle is returned to the original position of the tool magazine. It is preferable. The machine tool is provided with a tool magazine capable of individually accommodating a plurality of spindle tools, and a spindle tool suitable for processing a workpiece is selected from the tool magazine and attached to the spindle to operate the machine tool. Therefore, when the operation stop time of the spindle exceeds a predetermined time, the spindle tool is returned to the original position of the tool magazine. By handling the spindle tool in this way, it is possible to prepare for the selection of the spindle tool in the next stage.

  In this spindle tool handling method, after the operation of the spindle is stopped, it is determined whether or not the operation of the machine tool is stopped, and the stop of the operation of the machine tool is further set as a condition. Can be removed from the spindle. By stopping the operation of the machine tool as a condition for removing the spindle tool from the spindle, the spindle tool is removed from the spindle after a predetermined time has elapsed since the spindle stopped only when the spindle stops and the machine tool also stops. It is possible to cope with the possibility that the operation of the main spindle may be resumed at any time when the main spindle is temporarily stopped and the machine tool is continuously operating, or immediately resumes operation.

  In this spindle tool handling method, it is possible to warn of the removal of the spindle tool from the spindle in response to the elapse of the predetermined time. It is preferable that the spindle tool is automatically removed from the spindle when a predetermined time has elapsed since the spindle operation was stopped. In this case, the operation for removing the spindle tool or returning it to the tool magazine can be a dangerous operation for an operator engaged in the machine tool. Therefore, warning of the removal of the spindle tool from the spindle can ensure the safety of the worker.

  In this spindle tool handling method, when removal of the spindle tool from the spindle is in the middle of execution of a machining program of the machine tool, the spindle tool removed from the spindle is restarted when the spindle is restarted. It can be reattached to the main shaft. When a machine tool is started or restarted after the machining program has been executed, a specific spindle tool is not used. Generally, the spindle tool is selected in accordance with the machining of the workpiece at that time. . However, during the execution of the machining program for the machine tool, when the spindle tool is removed when the operation stop of the spindle exceeds a predetermined time, it is assumed that machining using the spindle tool is performed again. Therefore, in this case, when the spindle is restarted, it is efficient in terms of machine operation to reattach the spindle tool removed from the spindle to the spindle.

  In the spindle tool handling method according to the present invention, as described above, since the spindle tool is removed from the spindle in response to a lapse of a predetermined time after the spindle operation is stopped, the spindle raised during the spindle operation is taken. Even if the temperature of the spindle decreases after the operation is stopped, if the operation stop time of the main shaft exceeds a predetermined time, the main spindle tool is removed from the main shaft in response to the elapse of the predetermined time. It avoids the situation where it becomes extremely difficult to remove the spindle tool from the spindle without the occurrence of biting to the extent that it becomes difficult to separate due to heat shrinkage at the joint portion such as the tapered portion of the spindle and the tool. be able to. Therefore, it is possible to ensure the execution of the ATC and prevent parts related to the tool changer such as the tool gripper and the tool drum from being damaged.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment according to a method for handling a spindle tool according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a flowchart showing an embodiment of a spindle tool handling method according to the present invention, and FIG. 2 is a flowchart showing an example of start-up processing when resuming operation of a machine tool after execution of the flowchart shown in FIG.

  In factories and the like, the operation of machine tools is constantly monitored. According to the flowchart of the spindle tool removal process shown in FIG. 1, it is first determined whether or not the spindle has stopped (step 1, abbreviated as “S1”, the same applies hereinafter). If it is determined in S1 that the spindle is rotating, the warning display & warning buzzer is released (or the released state continues, the same applies hereinafter) (S7). When it is determined in S1 that the main shaft is stopped, it is determined whether or not the operation of the machine is stopped (S2). If it is determined by this determination that the operation of the machine is continued, the warning display & warning buzzer is canceled (S7). If it is determined in S2 that the operation of the machine is stopped, it is determined whether or not the spindle has been stopped for a set time (S3). If the spindle stop is short and less than the set time, the warning display & warning buzzer is canceled (S7).

  When it is determined in S2 that the machine operation has been stopped for more than the set time while the machining program is stopped halfway due to a break time such as a lunch break and the spindle is stopped The warning display & warning buzzer is turned on (S4), and the operator is informed accordingly. Next, it is determined whether or not the safety fence is in a closed state (S5). If it is determined in S5 that the safety fence is not closed, the process returns to S1 and the processes from S1 are repeated. When it is determined in S5 that the safety fence is closed, an operation of removing the tool from the main spindle is executed (S6). In this operation, the fact that the tool has been removed during the machining operation is stored, and the return tool number, that is, the spindle tool number returned to the tool magazine is stored.

  Since the machine is generally started from the beginning of the machining program, a program is prepared so that tool selection corresponding to the machining is executed at the beginning of the machining program. Therefore, the function of automatically returning to the tool used at the end of the pre-processing at the time of start-up is unnecessary. Also, when restarting a program, it is common to select a tool in accordance with the restart at the time of execution. In the present embodiment, a function is added to return the tool that has been automatically removed from the spindle and returned to the tool magazine at the time of activation to the spindle. This function is advantageous in that it can be resumed when the machine is stopped and interrupted during the machining program. This function is useful only when resuming continuous operation from an interruption that is not normally performed.

  The flowchart shown in FIG. 2 is a start-up process flowchart of the machine tool after the tool is separated when the main shaft stops exceeding a predetermined time. First, it is determined whether a start command has been issued (S10). If the determination in S10 is no, the process returns. If the determination in S10 is affirmative, it is determined whether or not the machine tool can be started (S11). If the determination in S11 is negative, the process returns. If it is determined in S11 that the machine tool can be started, it is determined whether or not the tool attachment is valid (S12). In processing other than this flowchart, the “tool attachment valid” state is stored at the start of machining, and the “tool attachment invalid” state is entered when machining is completed or stopped. By doing so, it is possible to switch whether or not the tool automatically returned during the machining should be mounted on the spindle again or not in the determination of S12. If it is determined in S12 that the tool attachment is not valid, the process skips to S15 and a predetermined machining program is activated. If the tool attachment is valid, it is determined whether or not the tool removal is stored (S13). If it is determined in S13 that tool removal has not been stored, the process skips to S15 and a predetermined machining program is activated. If the tool removal is stored, the tool attachment operation is executed (S14), and the spindle tool used until the previous stop is attached again. In this case, the memory for removing the tool is turned off. Thereafter, a machining program for the machine tool is started in S15, and machining with the same tool is resumed.

The flowchart which shows one Example of the handling method of the spindle tool by this invention. The flowchart which shows an example of the starting process when performing the driving | operation restart of the machine tool after execution of the flowchart shown in FIG. The front view which shows a part of armless automatic tool change roughly, and shows the operation | movement aspect in steps.

Explanation of symbols

1 Spindle 2 Spindle Sleeve 3 Tapered Hole 10, 11 Spindle Tool 12 Tapered Part 20 Tool Magazine 21 Tool Drum

Claims (5)

  In a machine tool comprising a driven spindle and a spindle tool for machining a workpiece attached to the spindle, the spindle tool is removed from the spindle in response to a lapse of a predetermined time after the operation of the spindle is stopped. Spindle tool handling method consisting of removing.   The machine tool comprises a tool magazine capable of individually accommodating a plurality of spindle tools, and the spindle tool removed from the spindle is returned to the original position of the tool magazine. Handling method of the spindle tool described.   After the operation of the spindle is stopped, it is determined whether or not the operation of the machine tool is stopped, and the spindle tool is removed from the spindle under the further condition of stopping the operation of the machine tool. The method for handling a spindle tool according to claim 1.   2. The method for handling a spindle tool according to claim 1, further comprising warning the removal of the spindle tool from the spindle in response to the elapse of the predetermined time. When the removal of the spindle tool from the spindle is in the middle of execution of the machining program of the machine tool, the spindle tool removed from the spindle is reattached to the spindle when the spindle is restarted. The handling method of the spindle tool according to claim 1.

Images