CN-117840885-B - Safety detection and control method for automatic workpiece loading and unloading of grinding machine

CN117840885BCN 117840885 BCN117840885 BCN 117840885BCN-117840885-B

Abstract

The invention relates to a safety detection and control method for automatically loading and unloading workpieces of a grinding machine, which is used for detecting and controlling the automatic loading and unloading of the workpieces of the grinding machine, wherein a PLC (programmable logic controller) is used for determining whether a manipulator can serve the grinding machine or not by receiving a position signal detected by a motion position sensor of a grinding wheel frame, a workbench, a headstock driving device, a tailstock jacking device, a workpiece bracket pulling device, a center rest stabilizing device, an outer diameter measuring instrument, an end surface measuring instrument, a workpiece thrust device and a protective door and a workpiece sensing sensor, so that the manipulator is ensured not to interfere with the up-down loading and unloading motion of the workpiece when the manipulator provides the workpiece loading and unloading service for the grinding machine on an automatic production line, namely the manipulator, the grabbed blank and the internal parts of the grinding machine are not interfered before the grinding machine sends a workpiece loading and unloading request, and the workpiece is not interfered with the internal parts of the grinding machine in the upward motion process of the grabbing workpiece.

Inventors

YAO JIANGWEI
HU ZEHUI
XIE ZHILI
WU JIEYU
WANG XUEDONG
FANG XIAOYAN

Assignees

上海机床厂有限公司

Dates

Publication Date: 20260505
Application Date: 20240222

Claims (3)

1. A safety detection and control method for automatically loading and unloading workpieces of a grinding machine is used for detecting and controlling the automatic loading and unloading workpieces of the grinding machine and is characterized by comprising a manipulator, a grinding carriage, a workbench, a headstock driving device, a tailstock jacking device, a workpiece bracket pulling-out device, a center rest stabilizing device, an outer diameter measuring instrument, an end face measuring instrument, a workpiece induction sensor, a workpiece thrust device and a protective door, wherein a PLC (programmable logic controller) receives the grinding carriage, the workbench, the headstock driving device, the tailstock jacking device, the workpiece bracket pulling-out device, the center rest stabilizing device, the outer diameter measuring instrument, the end face measuring instrument and the end face measuring instrument through a receiving grinding carriage, the workbench, the headstock driving device, the tailstock jacking device, the workpiece bracket pulling-out device and the center rest stabilizing device, The workpiece thrust device and the motion position sensor of the protective door detect an in-place signal and a workpiece induction sensor detect signal to determine whether the manipulator can serve the grinding machine or not, so that when the manipulator provides workpiece loading and unloading service for the grinding machine on an automatic production line, the manipulator is ensured not to interfere with the up-and-down workpiece loading and unloading motion of the grabbing workpiece, namely, before the grinding machine sends out workpiece loading request service, the manipulator, the grabbing blank and parts in the grinding machine are not interfered; the grinding machine is characterized in that before a workpiece unloading request is sent out, a mechanical arm does not interfere with mechanical parts in the grinding machine except contact with the workpiece and does not interfere with the parts in the grinding machine in the process of upwards moving after grabbing the workpiece, the grinding carriage is driven back and forth through an X-axis of a servo motor, when the grinding wheel is trimmed or processed, the grinding carriage is retracted to a designated safe position and sends out an in-place signal to the PLC, the workbench is driven left and right through a Z-axis of the servo motor, when the grinding wheel is trimmed or processed, the workbench is moved to a designated safe position and sends out an in-place signal to the PLC, the headstock driving device is arranged on the left side of the workbench and drives the workpiece to rotate when the workpiece, in order to ensure that the workpiece does not interfere with other parts in the process of unloading the workpiece after the processing is finished, the workpiece is stopped at a preset safe angle position, the position is determined through a contactless inductive switch, the inductive confirmation signal is sent to the PLC, the tailstock jacking device is arranged on the right side of the workbench, the workpiece is placed on a bracket, the tailstock is moved to a designated safe position by a hydraulic tailstock, and finally the tailstock is driven to rotate by the tailstock and the headstock driving device, before the manipulator loads and unloads the workpiece, the tail frame center must be retreated to a retreating position, a space is reserved for the manipulator to grasp the workpiece, and after the non-contact inductive switch is required to confirm that the tail frame center is in place when the tail frame center retreats to the retreating position, an in-place signal is sent to the PLC for logic processing; the workpiece bracket pulling device is arranged on a workbench, is close to one of a headstock and a tailstock, and after the workpiece is machined, the tailstock center is moved back to a backward position, a bracket hydraulic cylinder is driven to the right, so that the workpiece is pulled out of the headstock center, the workpiece bracket pulling device is one of conditions of unloading the workpiece, when the workpiece is required to be installed, in order to prevent the workpiece from interfering with the bracket, the bracket hydraulic cylinder is driven to the left, the left and right states need to be confirmed by a contactless inductive switch and then send a signal to the PLC, the center rest stabilizing device is arranged close to the tailstock, the workpiece is pushed forward in the grinding process, after the grinding is finished, the center rest pushing structure is moved back and sends a signal of the backward position to the PLC, the outer diameter measuring instrument is arranged on the workbench surface and is close to the tailstock, and is just opposite to the gear of the workpiece, after the grinding is finished, the measuring instrument claw is moved back, the workpiece is completely separated from the workpiece and has a certain distance, the backward position is confirmed by the contactless inductive switch, if the position is in place, the position signal is sent to the PLC, the spindle end surface measuring instrument is arranged on a shell, the end surface measuring instrument is arranged in the grinding machine is axially, the end surface is offset by a hole is offset, and the end surface is offset by the axial direction is measured, and the end surface is offset is measured, and the end surface offset is measured by the end surface offset, and is measured, and is offset by the end surface is measured, and is offset, and is compared The slip of the tailstock jacking device comprises the following specific measurement steps: (1) Detecting slippage of headstock driving device The method comprises the steps that 1, a workbench is pre-reserved at a safe position, namely the workbench cannot interfere with components on the workbench when an end face measuring instrument advances, then a grinding carriage is driven to move forwards through an X-axis of a servo motor, and the workbench is driven to move left and right through a Z-axis of the servo motor until a ball end of the end face measuring instrument contacts with a right vertical face of a headstock driving device when the workbench moves; Step 2, driving the workbench to move rightwards through a Z axis of a servo motor, enabling the right vertical end face of the headstock to be in contact with the end face measuring instrument until the end face measuring instrument sends a signal, stopping the operation of the Z axis at the same time, and reading a mechanical coordinate value Z 4 of the Z axis at the moment, wherein the value is regarded as a reference value; Step 3, repeating the methods of the steps 1 and 2, reading the mechanical coordinate Z 5 of the Z axis, and then calculating the difference value of the two 1 =|Z 4 -Z 5 I, when the absolute difference between the two 1 Less than or equal to 0.1mm, and the range meets the requirement; (2) Slipping of tailstock jacking device The method comprises the steps that 1, a workbench is pre-reserved at a safe position, namely the workbench cannot interfere with components on the workbench when an end face measuring instrument advances, then a grinding carriage is driven to move forwards through an X-axis of a servo motor, and the workbench is driven to move left and right through a Z-axis of the servo motor until a ball end of the end face measuring instrument contacts with a left vertical face of a tailstock propping device when the workbench moves; Step 2, driving the workbench to move leftwards through a Z axis of a servo motor to enable the left vertical end face of the tailstock to be in contact with the end face of the end face measuring instrument until the end face measuring instrument sends a signal, stopping the operation of the Z axis at the same time, and reading a mechanical coordinate value Z 6 of the Z axis at the moment, wherein the value is regarded as a reference value; step 3, repeating the methods of the steps 1 and 2 when the tail frame is verified to have no slippage, reading the mechanical coordinate Z 7 of the Z axis, and then calculating the difference value of the two 2 =|Z 6 -Z 7 I, when the absolute difference between the two 2 Less than or equal to 0.1mm, and the range meets the requirement; The front guard gate is closed and locked before the grinding machine operates through manual opening and closing operation, and the whole process of grinding the grinding machine and loading and unloading the workpiece by the mechanical arm is closed and locked, and manual operation cannot be opened, and a closing and locking signal is sent to the PLC for processing; The method for controlling the manipulator to load and unload the workpiece to the grinding machine comprises the steps of checking each accessory of the machine tool after the grinding machine is electrified to ensure normal work, starting a hydraulic system and ensuring no alarm, closing and locking a front protective door, starting a grinding wheel, calling out a main program of the system and running, and controlling the running of a grinding wheel frame, a workbench, a headstock driving device, a tailstock jacking device, a workpiece bracket pulling device, a center rest stabilizing device, an outer diameter measuring instrument, an end face measuring instrument, a workpiece induction sensor, a workpiece thrust device and a protective door in the grinding machine by running an NC program, thereby meeting the condition that the manipulator can load and unload the workpiece to the grinding machine, and comprises the following specific steps: step 1, running an X-axis running position program to stop the grinding carriage at a backward safe position and send a signal to a grinding carriage backward safe position detection sensor; Step 2, running a Z-axis walking position program to stop the workbench at a position where the manipulator can load and unload the workpiece, and sending a signal from a safety position detection sensor for loading and unloading the workpiece by the workbench; step 3, operating a headstock spindle motor on the headstock driving device, and stopping the headstock spindle motor at a stopping position for enabling the headstock accurate stopping sensor to send a signal; Step4, executing an M instruction of lifting the end surface measuring instrument, and enabling the end surface measuring instrument to upwards so that a sensor on the end surface measuring instrument sends a signal; Step 5, executing a backward M instruction of the outer diameter measuring instrument, and enabling the outer diameter measuring instrument to retreat so that the outer diameter measuring instrument sends a signal to a rear sensor; Step 6, executing a rearward M instruction of the center frame, and enabling the center frame to retreat so that the center frame sends a signal to the rear sensor; Step 7, executing an M instruction of the tail frame center backwards, and enabling the tail frame center to backwards move so that a sensor behind the tail frame center sends out a signal; Step 8, executing an M instruction of moving the left bracket and the right bracket to the left, and enabling the left bracket and the right bracket to move to the left at the same time, so that the left bracket sends a signal at the left sensor and the right bracket sends a signal at the left sensor at the same time; step 9, executing an M instruction for opening the protective top door, and sending a signal from a sensor for completely opening the protective top door in place; After steps 1 to 9 are executed, the conditions for loading and unloading the workpiece to and from the grinding machine by the manipulator are met.
2. The method for safely detecting and controlling the automatic workpiece loading and unloading of the grinding machine according to claim 1, wherein the workpiece induction sensor is arranged on a bracket on the edge of the bracket, when the workpiece is placed on the bracket of the grinding machine, the workpiece induction sensor detects a signal and sends the signal to the PLC to make corresponding logic judgment, and the workpiece thrust device is arranged at a certain distance from the right end face of the workpiece when the tail frame center jacks up the workpiece, wherein the certain distance ensures that the bracket pulls out the workpiece and the left end face of the workpiece completely leaves the headstock center, and simultaneously ensures that the right end face of the workpiece has a certain distance from the tail frame center to the back-off position.
3. A method for automatically detecting and controlling the workpiece loading and unloading of grinding machine according to claim 1 is characterized in that if there is no workpiece in the grinding machine, the main program jumps to the sub-program for loading the workpiece by program logic judgment, the grinding machine sends a workpiece loading request to the mechanical hand, after loading the workpiece, the program execution returns to the main program, the main program jumps to the sub-program for grinding the workpiece by logic judgment, the tail frame center automatically lifts up the workpiece and calls the grinding sub-program, after grinding is finished, the program returns to the main program again, the main program jumps to the sub-program for unloading the workpiece by program logic judgment, the mechanical hand sends a workpiece unloading request to the grinding machine, the workpiece unloading sub-program executes the steps 1 to 9, wherein, step 8 becomes to execute an M instruction from the left bracket to the right, and makes the left bracket and the right bracket send signals to the right sensor simultaneously, when the workpiece is in the grinding machine and before grinding is finished, a grinding completion signal is sent by the grinding machine, when the main program is executed, the program logic judgment is returned to the mechanical hand, the workpiece unloading is sent to the mechanical hand by program logic judgment, and finally, the workpiece unloading sub-program is not required to be cycled to the grinding machine by the program when the logic judgment is finished, and the workpiece unloading program is finished.

Description

Safety detection and control method for automatic workpiece loading and unloading of grinding machine Technical Field The invention relates to an electrical control method for an automatic production line to provide absolute safety guarantee, wherein a grinding machine is in an absolute safety state before a mechanical arm loads and unloads workpieces to the grinding machine, and belongs to the technical field of automatic intelligent factories. Background In the actual machining process, the control of each mechanical moving part is controlled through a hydraulic or pneumatic electromagnetic valve, but when an NC program is operated, whether the mechanical part is really in place or not cannot be determined, if the mechanical part is not completely in place, the mechanical arm can collide in the process of loading and unloading a workpiece to a grinding machine, and the mechanical arm and the parts in the grinding machine are damaged. The shaft coupling that servo motor's main shaft and ball screw are connected is like adopting spring type shaft coupling, and servo motor is semi-closed loop control, and servo motor has the condition that the shaft coupling skidded in the operation in-process, because long-term accumulation produces the deviation, the result is that actual mechanical position and numerical control show the mechanical coordinate value deviation too big to lead to the manipulator in the in-process of loading and unloading work piece for the grinding machine, the work piece that manipulator or manipulator snatched collides with the part in the grinding machine. A sensor of a contactless inductive switch is arranged in the grinding machine and is used for sensing whether a workpiece exists in the grinding machine. When running the NC program, the program determines whether to load or unload the workpiece to or from the grinding machine by logic judgment, and at this time, the signal is collected to make judgment. If this sensor fails, it does not signal or because the scrap iron in the grinding machine is covered on the sensor, so that an error signal is sent to the grinding machine, with the result that even if no workpiece is in the grinding machine, the grinding machine does not send a loading request signal to the manipulator, or even if a workpiece is in the grinding machine, the loading request signal is sent to the manipulator, so that the efficiency of the automatic production line or the damage of mechanical parts are affected. The main components arranged on the workbench are a headstock driving workpiece rotating device and a tailstock propping device, wherein in the actual machining process, the headstock or the tailstock slides to two sides due to overlarge hydraulic pressure, or the headstock and the tailstock device slide to two sides due to loosening of a fastener of an installation seat of the headstock and the tailstock device due to long-time use, so that the consequence is that after machining is finished, the position of a workpiece pulled out of a headstock center deviates, the workpiece cannot be completely separated from the headstock center after machining is finished, and the headstock center and the workpiece can be damaged when a later manipulator grabs the workpiece. After the grinding machine finishes processing, the hydraulic driving part dials out the workpiece from the head rest center, but the condition that the workpiece is dialed out too much or not in place exists in the process of dialing out, so that mechanical parts in the grinding machine are damaged when a mechanical arm grabs the workpiece, and the position positioning of the workpiece in the subsequent process is affected. In the running process of the numerical control program, the protection door of the grinding machine is normally in a closed state, but in the practical process, an operator is convenient to view, the bolt of the protection door is detached privately, then the bolt is inserted into the electromagnetic lock hole, so that the protection door is in a closed false image, and the consequence caused by the false image is that very great damage can be brought to people. Disclosure of Invention The invention aims to realize that a manipulator of an automatic production line loads and unloads workpieces on a grinding machine, avoids the mutual interference of the manipulator and the grinding machine and avoids the injury to operators, and provides a safety detection and control method for automatically loading and unloading the workpieces on the grinding machine, in order to prevent accidents, and the safety detection and control method is used for detecting the in-place state of each moving part by using a large number of non-contact induction sensors, and ensuring the safe and efficient operation of the automatic production line by adopting a control method combining an NC program and a PLC program, and connecting and communicating the two parts and exchanging data. The technical scheme of