Grinding control system based on rotatable temperature measurement grinding wheel

Abstract

The invention discloses a grinding control system based on a rotatable temperature measurement grinding wheel, which comprises the rotatable temperature measurement grinding wheel, a temperature acquisition module, a PC (Personal Computer) upper computer, a PLC (Programmable Logic Controller), a spindle motor system, a servo motor system, a liquid cooling system and an air cooling system, the temperature acquisition module is connected with the PC upper computer, the PC upper computer is connected with the PLC, the PLC is connected with the spindle motor system, the servo motor system, the cooling system and the air cooling system, the PC upper computer serves as a control center, set temperature serves as an input variable, a Labview program is adopted for comparing the set temperature with the temperature measured in real time by rotating the temperature measurement grinding wheel, and the set temperature is obtained. And then the PLC is controlled to carry out multi-input single-output PI D feedback control, series grinding process parameters such as the rotating speed of the grinding wheel, the workpiece feeding amount and the cooling liquid supply amount are regulated and controlled, the grinding temperature is constant, the grinding heat damage of the workpiece is effectively reduced, and the surface grinding quality of the workpiece is improved.

Description

Technical Field

[0001] The invention relates to the technical field of precision grinding, in particular to a grinding control system based on a rotatable temperature measuring grinding wheel. Background Art

[0002] Grinding with grinding wheels is widely used in the manufacturing industry and can be used to process workpieces of various materials. Including metal materials, non-metallic materials, composite materials, etc., involving various fields such as automobiles, aerospace, ships, machine tool manufacturing, ceramics, glass, plastics, etc. The factors affecting the grinding process of grinding wheels are complex. Among them, temperature control has an important impact on product quality and life. A large amount of frictional heat will be generated during grinding with grinding wheels. If the heat is not dissipated in time, the workpiece will be deformed, the surface quality will be reduced, and even its service life will be affected. Therefore, during the grinding process, the temperature must be controlled to ensure the processing quality. Therefore, how to effectively monitor, reduce and control the grinding temperature of the grinding wheel is crucial to improving the surface quality, dimensional accuracy level and service life of the processed parts.

[0003] At present, there are grinding temperature monitoring methods based on visual image processing technology. This method analyzes temperature information through digital image processing technology. However, due to the influence of many factors such as process, grinding processing environment, light, etc., this technology is prone to errors. Another method is to measure grinding temperature based on fiber optic sensing and infrared radiation technology, but due to the high-speed rotation of the grinding wheel and the interference of the polishing liquid, this technology is difficult to accurately measure the temperature. Another method is the traditional workpiece drilling temperature sensor measurement method. Since the workpiece needs to be drilled, it will cause damage to the workpiece. Therefore, it is only limited to experimental measurement and is not suitable for actual processing. And for materials with low thermal conductivity, the measurement error is extremely large.

[0004] In summary, the existing research and application of grinding temperature is more limited to temperature monitoring and collection, and there are unstable measurement errors. Therefore, how to effectively and continuously measure the grinding temperature and control the grinding parameters by temperature to reduce and control the constant grinding temperature to ensure the processing quality needs to be solved urgently. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a grinding control system based on a rotatable temperature measuring grinding wheel. The system collects the grinding temperature in real time during the grinding process through a vertical rotating temperature measuring grinding wheel with a built-in temperature measuring thermocouple, calculates the collected temperature through a Labview program in a PC host computer and compares it with the set temperature. The comparison result is transmitted to a PLC, and the PLC performs multi-input and single-output PID feedback control on the system to adjust a series of grinding process parameters such as the grinding wheel speed, workpiece feed rate, and coolant supply rate, so as to achieve and control a constant grinding temperature, effectively reduce the thermal damage of the workpiece surface during grinding, and improve the surface quality of the workpiece grinding process.

[0006] The technical solution of the present invention is: a grinding control system based on a rotatable temperature measuring grinding wheel: including a rotatable temperature measuring grinding wheel, a temperature acquisition module, a PC host computer, a PLC, a spindle motor system, a servo motor system, a liquid cooling system, and an air cooling system.

[0007] As a key component of the system, the rotatable temperature measuring grinding wheel can perform stable electrical transmission during the rotation of the grinding wheel during grinding, realize real-time and effective temperature measurement, and has no interference with the processing process. It consists of a blade, a rotating conductive mechanism, a terminal, a temperature measuring thermocouple, a temperature measuring disk, and a grinding wheel; wherein, the rotating conductive mechanism is fixed to the blade with a hexagon socket bolt, the inside of the blade is a partially hollow structure, and there are threading holes on the circumferential side. The outlet wire of the rotating conductive mechanism is connected to one end of the terminal through the threading hole inside the blade, and the other end of the terminal is connected to the temperature measuring thermocouple terminal; the temperature measuring end of the temperature measuring thermocouple is built into the temperature measuring slot on the temperature measuring disk. The temperature measuring thermocouples in the system are divided into three groups, which are evenly distributed in the temperature measuring slots in the temperature measuring disk at 120° in turn to reduce the measurement error. The temperature measurement range of the temperature measuring thermocouple is -50℃-700℃.

[0008] The rotatable temperature measuring grinding wheel is connected to the temperature acquisition module through the input terminal of the rotating conductive mechanism thereon. The temperature acquisition module type is a virtual instrument temperature acquisition card which transmits data with the PC host computer through Ethernet. At the same time, it provides a temperature acquisition program block that matches Labview.

[0009] The PC host computer serves as the human-computer interaction device of the system. It monitors and controls the system through the Labview program. The temperature data collected by the rotatable temperature measuring grinding wheel is processed and displayed in real time through the Labview program.

[0010] As the control center, PLC includes the main CPU, analog input module and analog output module. The CPU is connected to the PC host computer via RS485 communication.

[0011] The spindle motor system includes a spindle and a spindle variable frequency motor. The rotatable temperature measuring grinding wheel is installed on the spindle and driven to rotate by the spindle variable frequency motor. The spindle variable frequency motor is connected to the analog output and input expansion module of the PLC, and the speed is adjusted through the PLC analog output feedback control. At the same time, real-time speed monitoring is performed through the analog input feedback control.

[0012] The servo motor system includes an X-direction feed servo motor, a Y-direction feed servo motor, and a Z-direction feed servo motor, which control the feed of the machine tool worktable in three directions (XYZ) respectively. The three servo motors are all connected to the analog output and input expansion modules of the PLC. The servo feed is adjusted through the PLC analog output, and the workpiece feed amount is monitored in real time through the analog input.

[0013] The liquid cooling system includes a coolant tank, a hydraulic pump, an electric butterfly valve, a flow meter, and a liquid delivery pipe. The coolant tank, the hydraulic pump, the electric butterfly valve, and the flow meter are interconnected through the liquid delivery pipe. The hydraulic pump is connected to the DO interface on the PLC main CPU, and the electric butterfly valve is connected to the analog input and output module of the PLC. When the system is running, the hydraulic pump is turned on by the PLC control, and the grinding coolant is transmitted from the hydraulic pump to the electric butterfly valve through the liquid delivery pipe, and then transported to the workbench by the electric butterfly valve to dissipate heat for the grinding wheel and workpiece. The opening of the electric butterfly valve is controlled by the PLC analog output feedback, thereby controlling the delivery flow of the grinding fluid. At the same time, the flow is monitored in real time by the PLC analog input.

[0014] The air cooling system includes an air cooler and an air cooling pipe. The air cooler is directly connected to the air cooling pipe to cool the grinding wheel and the workpiece. The air cooler is connected to the DO interface on the PLC main CPU. When the system is running, the air cooler is controlled to be turned on by the PLC.

[0015] The operation process of the present invention is as follows: the rotating temperature measuring grinding wheel is installed on the main shaft, and after the rotating temperature measuring grinding wheel is connected, the system is powered on. The machine tool sets the initial grinding parameters, the PC host computer sets the grinding temperature, and controls the PLC to turn on the hydraulic pump and the air cooler through the hydraulic pump switch button and the air cooler switch button. The machine tool starts, and the main shaft starts to rotate. At the same time, the rotating temperature measuring grinding wheel starts grinding and temperature collection is performed at the same time. The collected temperature is calculated and processed by the Labview program to obtain a stable temperature mean value. The program feeds back the stable temperature mean value and the real-time temperature comparison result to the PLC. The PLC controls the program through internal feedback, adjusts each analog output, and controls the main shaft variable frequency motor speed, X-direction feed servo motor feed, Y-direction feed servo motor feed, Z-direction feed servo motor feed, and electric butterfly valve opening through the analog output, thereby adjusting the temperature to a constant. During the processing, the PC host computer can be used to view the temperature, main shaft speed, XYZ direction servo motor workpiece feed, and coolant flow in real time. When the system is initially running, the PLC needs to be initially calibrated for PID feedback control to determine the appropriate temperature adjustment range.

[0016] Compared with the prior art, the technical effect of the present invention is that during grinding, the rotating temperature measuring grinding wheel can conduct electricity stably, thereby realizing temperature collection. At the same time, the temperature measuring thermocouple is placed on the surface of the grinding wheel to realize accurate temperature measurement. At the same time, the real-time temperature is collected in real time, and the Labview program in the PC host computer compares the set temperature with the real-time measured temperature of the temperature measuring grinding wheel, and then controls the PLC to perform multi-input single-output feedback control, adjust the grinding wheel speed, workpiece feed rate, coolant supply, air cooling system switch series grinding process parameters, control and realize constant grinding temperature, effectively reduce grinding thermal damage, and improve grinding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram according to an embodiment of the present invention;

[0018] Figure 2 is a cross-sectional view of the structure of a rotating temperature measuring grinding wheel according to an embodiment of the present invention;

[0019] Figure 3 is a diagram of the system hardware composition according to an embodiment of the present invention;

[0020] Figure 4 1. It is a diagram of a monitoring interface of a PC host computer according to an embodiment of the present invention; DETAILED DESCRIPTION

[0021] In order to more clearly understand the technical features, purposes and effects of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments, but the content of the present invention is not limited to the scope of the embodiments.

[0022] like Figure 1 As shown, a grinding control system based on a rotatable temperature measuring grinding wheel comprises a rotatable temperature measuring grinding wheel (1), a temperature acquisition module, a PC host computer, a PLC, a spindle motor system, a servo motor system, a liquid cooling system, and an air cooling system.

[0023] like Figure 1 and 2 As shown, the rotatable temperature measuring grinding wheel, as a key component of the system, can perform stable electrical transmission during the rotation of the grinding wheel during grinding processing, realize real-time and effective temperature measurement, and has no interference with the processing process. The invention comprises a blade (11), a rotating conductive mechanism (12), a terminal (13), a temperature measuring thermocouple (14), a temperature measuring disk (15), and a grinding wheel (16); wherein the rotating conductive mechanism (12) is fixed to the blade (11) by a hexagon socket bolt, the inside of the blade (11) is a partially hollow structure, and a threading hole is provided on the circumferential side; the outlet end (122) of the rotating conductive mechanism (12) is connected to one end of the terminal (13) inside the blade (11) through the threading hole, and the other end of the terminal (13) is connected to a terminal (141) of the temperature measuring thermocouple (14); the temperature measuring thermocouple (15) in the system is divided into three groups, and the temperature measuring ends (142) of the temperature measuring thermocouple (14) are uniformly distributed in a temperature measuring groove in the temperature measuring disk (15) at an angle of 120 degrees in sequence, so as to reduce the measurement error; the temperature measuring range of the temperature measuring thermocouple (14) is -50°C-700°C.

[0024] The rotatable temperature measuring grinding wheel (1) is connected to a temperature acquisition module via an input terminal (121) of a rotating conductive mechanism (12) thereon. The temperature acquisition module is a virtual instrument temperature acquisition card that transmits data with a PC host computer via Ethernet and provides a temperature acquisition program block that matches Labview.

[0025] The PC host computer serves as a human-computer interaction device of the system, and the system is monitored and controlled through the Labview program. The temperature data collected by the rotatable temperature measuring grinding wheel (1) is processed and displayed in real time through the Labview program.

[0026] As the control center, PLC includes the main CPU, analog input module and analog output module. The CPU is connected to the PC host computer via RS485 communication.

[0027] like Figure 1 and 3 As shown, the spindle motor system includes a spindle (21) and a spindle variable frequency motor (22), a rotatable temperature measuring grinding wheel (1) is mounted on the spindle (21) and driven to rotate by the spindle variable frequency motor (22), the spindle variable frequency motor (22) is connected to the analog output and input expansion module of the PLC, and the speed is adjusted through the PLC analog output feedback control, and the real-time speed monitoring is performed through the analog input feedback control.

[0028] like Figure 1 , 3 As shown in FIG. 4 , the servo motor system includes an X-direction feed servo motor (72), a Y-direction feed servo motor (73), and a Z-direction feed servo motor (71), which respectively control the feed of the machine tool worktable in three directions XYZ. The three servo motors are all connected to the analog output and input expansion module of the PLC, and the servo feed is adjusted through the PLC analog output. At the same time, the analog input is transmitted to the PC host computer to monitor the workpiece feed amount in real time.

[0029] like Figure 1 , 3 As shown in Figure 4, the liquid cooling system includes a coolant tank (31), a hydraulic pump (32), an electric butterfly valve (33), and a liquid delivery pipe (34), wherein the coolant tank (31), the hydraulic pump (32), the electric butterfly valve (33), and the flow meter (34) are interconnected through a liquid delivery pipe (35), the hydraulic pump (32) is connected to the DO interface on the PLC main CPU, and the electric butterfly valve (33) is connected to the analog input and output module of the PLC. The system is operated by controlling the PLC to turn on the hydraulic pump (32) through the hydraulic pump (32) switch button on the PC host computer, and the grinding coolant is transmitted from the hydraulic pump (32) to the electric butterfly valve (33) through the liquid delivery pipe (35), and then transported to the workbench (6) by the electric butterfly valve (33) to dissipate heat for the grinding wheel (16) and the workpiece (5). The opening of the electric butterfly valve (33) is controlled by the PLC analog output feedback, thereby controlling the delivery flow of the grinding fluid. At the same time, the PLC analog input is transmitted to the PC host computer to monitor the flow in real time.

[0030] like Figure 1 , 3As shown in FIG. 4 , the air cooling system includes an air cooler (41) and an air cooling pipe (42). The air cooler (41) is directly connected to the air cooling pipe (42) to cool the grinding wheel (16) and the workpiece (5). The air cooler (41) is connected to the DO interface on the PLC main CPU. When the system is running, the PLC is controlled to turn on the air cooler (41) through the switch button of the air cooler (41) on the PC host computer.

[0031] The operation process of the present invention is as follows: the rotating temperature measuring grinding wheel (1) is installed on the main shaft (21), the rotating temperature measuring grinding wheel (1) is connected, and the system is powered on. The machine tool sets the initial grinding parameters, the PC host computer sets the grinding temperature, and the hydraulic pump (32) and the cooling fan (41) are turned on by controlling the PLC through the switch button of the hydraulic pump (32) and the switch button of the cooling fan (41). The machine tool is started, and the spindle (21) starts to rotate. At the same time, the temperature measuring grinding wheel (1) is rotated to start grinding. At the same time, temperature is collected. The collected temperature is calculated and processed by the Labview program to obtain a stable temperature average. The program feeds back the stable temperature average and the real-time temperature comparison result to the PLC. The PLC adjusts each analog output through the internal feedback control program, and controls the spindle frequency conversion motor (22) speed, the X-direction feed servo motor (72) feed, the Y-direction feed servo motor (73) feed, the Z-direction feed servo motor (71) feed, and the opening of the electric butterfly valve (33) through the analog output, thereby adjusting the grinding temperature until the temperature is constant. During the processing, the grinding temperature, the spindle (21) speed, the X-direction servo motor workpiece feed (72), the X-direction servo motor (73) workpiece feed, the Z-direction servo motor (71) workpiece feed, and the coolant flow rate can be viewed in real time through the PC host computer. When the system is initially running, it is necessary to perform PID feedback control initial calibration on the PLC to determine the appropriate temperature adjustment range.

[0032] The thermocouple (14) of the present invention comprises three groups of thermocouples, each group of thermocouples comprises two wires, and both have high temperature resistance and waterproof functions. Each group of temperature measuring thermocouples (14) is numbered and marked to facilitate tracking of temperature signals.

[0033] Although embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that the present invention is not limited to the details of the specific embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is limited by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in a claim should not be regarded as limiting the claim involved.

Claims

1. A rotatable temperature measuring grinding wheel, characterized in that: It comprises a blade (11), a rotating conductive mechanism (12), a connecting terminal (13), a temperature measuring thermocouple (14), a temperature measuring disk (15), and a grinding wheel (16); The rotating conductive mechanism (12) is fixed to the blade (11) by means of a hexagon socket bolt, and the blade is connected to the temperature measuring disk (15) by means of a thread; the grinding wheel (16) is connected to the temperature measuring disk (15) by means of a hexagonal flange bolt; the temperature measuring end (142) of the temperature measuring thermocouple (14) is built into a temperature measuring groove on the temperature measuring disk (15), and its connection end (141) is connected to the output end (122) of the rotating conductive mechanism (12) by means of the connection terminal (13).

2. A rotatable temperature measuring grinding wheel according to claim 1; characterized in that: The interior of the blade body (11) is a partially hollow structure, and a threading hole is provided on the circumferential side. The output wire of the rotating conductive mechanism (12) is connected to the connection terminal (141) of the temperature measuring thermocouple (14) through the threading hole inside the blade body (11) through the connection terminal (13).

3. The rotatable temperature measuring grinding wheel according to claim 1, characterized in that: The temperature measuring thermocouples (14) are divided into three groups and are uniformly distributed at 120° in the temperature measuring tanks in the temperature measuring plate (15), and the temperature measuring range is -50°C to 700°C.

4. The grinding control system based on the above-mentioned rotatable temperature measuring grinding wheel is characterized in that: It includes a rotating temperature measuring grinding wheel (1), a temperature acquisition module, a PC host computer, a PLC, a spindle motor system, a servo motor system, a liquid cooling system, and an air cooling system; The rotating temperature measuring grinding wheel (1) is connected to the temperature acquisition module via the input terminal (121) of the rotating conductive mechanism (12) thereon, the temperature acquisition module is connected to the PC host computer via an Ethernet port, the CPU of the PLC is connected to the PC host computer via RS485 to USB, and the PLC is respectively connected to the spindle motor system, the servo motor system, the liquid cooling system, and the air cooling system; The PLC comprises a main CPU, an analog input module and an analog output module. The PC host computer performs system monitoring and control through the Labview program; The spindle motor system comprises a spindle (21) and a spindle variable frequency motor (22); The servo motor system comprises an X-direction feeding servo motor (72), a Y-direction feeding servo motor (73), and a Z-direction feeding servo motor (71); The liquid cooling system comprises a coolant tank (31), a hydraulic pump (32), an electric butterfly valve (33), and a liquid delivery pipe (34); The air cooling system comprises an air cooler (41) and an air cooling pipe (42).

5. The grinding control system of the rotatable temperature measuring grinding wheel according to claim 4 is characterized in that: The analog input module interface and the analog output module interface of the PLC are respectively connected to the spindle frequency conversion motor (22) in the spindle motor system, the X-direction feed servo motor (72), the Y-direction feed servo motor (73), and the Z-direction feed servo motor (71) in the servo motor system, and the electric butterfly valve (33) in the liquid cooling system; the series DO interface on the CPU of the PLC is respectively connected to the hydraulic pump (32) in the liquid cooling system and the air cooler (41) in the air cooling system.

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