1、 Principle of automatic tool change of tool magazine
The tool magazine includes a tool sleeve rotating mechanism and a tool changing manipulator. The shape of the tool magazine is disc-shaped, and a dividing disc is installed inside. The rotary motion of the magazine is powered by a three-phase asynchronous motor with a band brake. The three-phase power supply is supplied to the motor through the AC contactor. At this time, the holding brake is opened and the tool magazine operates. When the three-phase power supply is cut off, the holding brake is locked and the tool magazine immediately stops running. Through the movement of the dividing disc and the logical combination of the related detection element group, each tool sleeve can stop at the tool change position accurately. After the tool sleeve stops at the tool change position, the cylinder controls the tool sleeve to be in the horizontal or vertical state, so as to facilitate the manipulator to change the tool. The tool sleeve indexing table can rotate clockwise or counterclockwise, so that the tool to be replaced can be searched in the shortest time.
The motion of the tool changing manipulator of the tool magazine is also powered by the three-phase asynchronous motor with band brake. Through the gear transmission mechanism, the uniform rotation motion generated by the motor is transformed into the regular forward, stop and rotation motion of the manipulator. The gear unit is equipped with a microswitch set. The micro switch group is used to control the manipulator to clamp the tool, the manipulator to take the tool out of the spindle and tool sleeve, and the manipulator to be in the original position.
A torque limiter is built in the rotating tool sleeve of the tool magazine and the reduction transmission mechanism of the manipulator to prevent damage to the internal mechanical structure.
2、 Specific implementation of automatic tool change of tool magazine
The manipulator of tool magazine is the main mechanism to realize automatic tool change. Its task is to unload the unused tools from the spindle and return them to the tool magazine after a process is completed. At the same time, it also loads the tools of the next process into the spindle, and then the manipulator returns to the original position to wait for the next work cycle.
The regular movement of the tool magazine manipulator is realized by three-phase asynchronous motor and gear transmission mechanism, but these actions also need to be realized by the electrical system. The tool sleeve in the tool magazine operates to the tool change position according to the instruction of T code, and then the tool exchange is carried out. During the working process of the machine tool, the tool makes the manipulator take or install the tool according to the instruction. Therefore, the electrical system is required to complete each action accurately and reliably according to the motion sequence of the tool change process.
Electrical action sequence:
(1) Start the tool selection, and the tool magazine rotates forward or backward to find the nearest tool.
(2) The tool sleeve counting and indexing disc positioning signals stop the tool sleeve motor, and a tool sleeve accurately stops at the tool change position.
(3) The electric phosphorus valve that controls the turning (vertical) of the knife sleeve is powered on.
(4) When the tool sleeve is vertically in place, a position signal is sent, and the spindle orientation gives a position arrival confirmation signal.
(5) The manipulator starts from the original position and rotates 90 ° to reach the tool clamping position of the manipulator.
(6) The manipulator snaps the knife in place, sends a stop signal, takes the knife out of the spindle and knife sleeve, and the manipulator motor stops.
(7) The tool clamping confirmation and tool loosening give a signal in place.
(8) After the tool holder is loosened, start the manipulator to rotate 180 ° to reach the tool replacement position.
(9) The robot motor stop signal stops the robot motor.
(10) The tool loading confirmation and tool clamping will give the signal in place.
(11) The manipulator motor starts to return the manipulator to its original position.
(12) The robot motor stop signal stops the robot motor.
(13) The original position switch of the manipulator sends a signal.
(14) The electromagnetic air valve that controls the turning (horizontal) of the knife sleeve is powered on.
(15) The proximity switch with the sleeve overturned in the horizontal position sends a signal (the tool change action of the tool magazine is completed).