A method for measuring grinding temperature online using a coating thermocouple

Abstract

A method for online measurement of grinding temperature by using a coating thermocouple belongs to the technical field of grinding temperature measurement. In order to solve the problem of measuring the end face grinding temperature by measuring the temperature in the gap between thermocouples, there are problems such as large temperature measurement area, inaccurate temperature measurement and influence on the integrity of the workpiece. The measurement process of the present invention is as follows: Step 1, cutting and processing the workpiece; Step 2, determining the installation position of the coating thermocouple: determining the feed position, inlet position and outlet position of the cup-shaped grinding wheel on the workpiece to be ground after cutting; Step 3, installing the coating thermocouple: at the feed position, inlet position and outlet position of the cup-shaped grinding wheel, and in the slit between two adjacent workpiece units, a coating thermocouple is arranged respectively; Step 4, bonding the workpiece and measuring the conductivity of the coating thermocouple: bonding the workpiece units after cutting, and measuring the conductivity of the coating thermocouple; Step 5, calibration of the coating thermocouple; Step 6, online measurement. The present invention is mainly used to measure the temperature of the grinding area.

Description

Technical Field

[0001] The invention belongs to the technical field of grinding temperature measurement, and in particular relates to a method for measuring grinding temperature online using a coating thermocouple. Background Art

[0002] As a high-precision, high-rigidity and high-efficiency processing method, cup wheel end grinding technology is widely used in the manufacture of key components in the fields of aviation, aerospace and national defense, especially in the processing of stone, artificial crystals, single crystal silicon and ceramics.

[0003] The end face grinding technology of cup grinding wheel has the characteristics of high efficiency and low damage. However, end face grinding also has its disadvantages: due to the large contact area between the grinding wheel and the workpiece, the number of abrasive grains involved in cutting is large, and a large amount of grinding heat will be generated, so the impact of grinding heat is the most serious. Therefore, monitoring the end face grinding temperature of the cup grinding wheel to avoid thermal damage and thermal cracks caused by high temperature is crucial for the processing quality and surface accuracy of the processed parts. Among various grinding temperature measurement methods, the use of thermocouples is the most common. The working principle of thermocouples is based on the Seebeck effect, that is, when two different metals or semiconductor materials are in contact or welded together, if the temperatures of the two connection points are different, an electric potential difference will be generated. This potential difference is related to the material and its temperature difference. The grinding temperature signal is converted into an electrical signal by a thermocouple, and then the electrical signal is amplified, and then input into the computer through the digital-to-analog conversion of the data acquisition device, and finally the grinding temperature is obtained by analysis through special software. Generally, they are divided into the following categories according to the installation method and measurement principle: buried wire thermocouple, clamped wire thermocouple, two metal sheet thermocouple, thermocouple grinding head method and contact thermocouple method.

[0004] In industry, the end grinding temperature is usually measured by thermocouple gap temperature measurement. However, when using this method to measure temperature, the thickness of the thermocouple will affect the integrity of the workpiece and cannot accurately reflect the temperature changes in the grinding area. At the same time, the area measured by the thermocouple is large and cannot accurately measure the area to be measured; and the thermocouple is easily affected by the external physical field, and the measurement is unstable. Summary of the invention

[0005] The present invention aims to solve the problems of measuring the end face grinding temperature by measuring the temperature through the gap of thermocouples, such as large temperature measurement area, inaccurate temperature measurement and influence on the integrity of the workpiece; and further provides a method for measuring the grinding temperature online by using a coating thermocouple.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A method for measuring grinding temperature online by using a coating thermocouple, wherein a plurality of coating thermocouple temperature measuring units are used to measure the grinding temperature, each coating thermocouple temperature measuring unit comprises a coating thermocouple and a high-frequency temperature data collector, and the coating thermocouple is electrically connected to the high-frequency temperature data collector; the measuring process comprises the following steps:

[0008] Step 1: Cutting and processing the workpiece: using a wire cutting machine to cut the workpiece to be ground into at least four workpiece units, and polishing the side of each workpiece unit;

[0009] Step 2, determine the installation position of the coating thermocouple: assemble the divided workpiece units into the initial shape of the workpiece to be ground, determine the feed position, inlet position and outlet position of the cup-shaped grinding wheel on the cut workpiece to be ground, and the slit between two adjacent workpiece units at the feed position, inlet position and outlet position is the installation position of the coating thermocouple;

[0010] Step 3, installing the coating thermocouple: a coating thermocouple is arranged at the feeding position, the inlet position and the outlet position of the cup-shaped grinding wheel, and in the slit between two adjacent workpiece units;

[0011] Step 4, bonding the workpiece and measuring the conductivity of the coated thermocouple: bonding the cut workpiece units and measuring the conductivity of the coated thermocouple;

[0012] Step 5, calibration of the coating thermocouple: use a device with a relatively fixed temperature environment to calibrate the coating thermocouple. During the calibration process, a calibrated thermometer is used as a reference. The two leads of the coating thermocouple are respectively connected to the positive and negative electrodes of the ammeter, and the corresponding currents at different temperatures are recorded in turn.

[0013] Step 6, online measurement: Clamp the calibrated coated thermocouple workpiece into the grinding system, connect the lead wire to the current amplifier and then to the high-frequency temperature data collector. The high-frequency temperature data collector transmits the collected data to the computer software system and uses a multi-channel oscilloscope to display the measurement signal in real time, thereby realizing online measurement of the grinding temperature.

[0014] Preferably, in the step 1, the specific operation process is: clamping the workpiece to be ground on the wire cutting machine, cutting the workpiece to be ground into blocks using the wire cutting machine under coolant conditions, and dividing it into at least four workpiece units; using a planetary wheel polishing machine to polish the side of each workpiece unit.

[0015] Preferably, in step 2, the process of determining the installation position of the coated thermocouple is as follows: along the forward direction of the cup-shaped grinding wheel, the center position of the cup-shaped grinding wheel is the feeding position of the grinding wheel, in the radial direction of the cup-shaped grinding wheel, the position corresponding to the left end grinding surface of the cup-shaped grinding wheel is the import position / export position, and the position corresponding to the right end grinding surface of the cup-shaped grinding wheel is the export position / import position.

[0016] Preferably, in step 3, the specific operation process is:

[0017] Step 3.1, local gold spraying: using an ion sputtering device to locally spray gold on the side of the workpiece unit and at the position where the coating thermocouple is to be installed, using a high voltage to excite gold ions and sputter them onto the side surface of the workpiece unit, while making the gold spraying positions between two adjacent workpiece units relatively set; the gold spraying operation is repeated multiple times to form a conductive gold spraying layer;

[0018] Step 3.2, electroplating and depositing metal layers: electroplating and depositing the gold-sprayed workpiece units at room temperature using an electroplating device, and electroplating and depositing a copper metal layer and a nickel metal layer at the gold-sprayed positions between two adjacent workpiece units, respectively, so that the upper end surfaces of the copper metal layer and the nickel metal layer are flush with the surface of the workpiece to be ground;

[0019] Step 3.3, make solder joints on the copper metal layer and the nickel metal layer respectively at a position away from the grinding surface and connect the leads. The two leads are led out from the side away from the grinding area. At the same time, a mica sheet is inserted between the copper metal layer and the nickel metal layer to avoid signal interference; connect the two leads to the positive and negative poles of a sensitive ammeter or a multimeter respectively, and use a sensitive ammeter or a multimeter to test the quality of the solder joints and leads to ensure good conductivity.

[0020] Preferably, in step 3.1, the thickness of the gold sprayed layer is 3-7 um.

[0021] Preferably, in step 3.2, the thickness of the copper metal layer and the nickel metal layer is 10-100 um.

[0022] Preferably, in step 4, the specific operation process is: apply glue to the side surfaces of two adjacent workpiece units and except for the metal layer position, the sides of the two adjacent workpiece units are pasted and fixed. After pasting and combining into the workpiece to be ground, the conductivity of the coated thermocouple is measured again by a multimeter to ensure good conductivity.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The current thermocouple gap temperature measurement method of this application is generally made by directly installing and manufacturing purchased metal sheets. On the one hand, the area of ​​the metal sheet is relatively large, and the coverage area is relatively large, so it is impossible to accurately measure the temperature of the grinding area; on the other hand, the metal sheet is relatively thick, resulting in a relatively large gap between the two workpiece units 3, which ultimately leads to incompleteness of the workpiece to be ground. However, this embodiment adopts the electroplating deposition method to make thermocouples in the gap of the workpiece to be ground. Copper metal and nickel metal with a very small area can be electroplated as needed, and the temperature of the grinding area can be accurately measured. The metal layer is relatively thin, which can ensure the integrity of the workpiece. In addition, the installation position of the thermocouple of this application is selected from the feed position, inlet position and outlet position of the cup-shaped grinding wheel. The temperatures of these three positions can represent the surface grinding temperature. In the surface grinding temperature of the cup-shaped grinding wheel, the inlet and outlet positions have relatively high temperatures and the middle temperature is low. This thermocouple arrangement method can reflect the grinding temperature.

[0025] 2. In the present application, when two workpiece units are bonded together, no glue is applied at the location of the coated thermocouple, and only glue is applied at the fitting surface of the workpiece unit, so the coated thermocouple is not covered, and is therefore not affected by external physical fields and is more stable and durable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are incorporated as part of this application and are used to provide a further understanding of the present invention.

[0027] Figure 1 This is the flow chart of the workpiece coating thermocouple preparation, where Figure 1 (a) is a schematic diagram of workpiece segmentation. Figure 1 (b) is to spray gold on the side of the workpiece and electroplatingly deposit copper metal layer and nickel metal layer, Figure 1 (c) To make wires and isolate interference for each electroplated thermocouple;

[0028] Figure 2 It is the thermocouple distribution diagram of the workpiece coating;

[0029] Figure 3 It is a schematic diagram of the thermocouple structure of the conductive / non-conductive material workpiece coating;

[0030] Figure 4 It is a schematic diagram of the grinding temperature data acquisition system using workpiece coating thermocouples;

[0031] Figure 5 This is an application example of the present invention, and is a schematic diagram of the structure of using a workpiece coating thermocouple to measure grinding temperature.

[0032] Figure 6 This is a grinding temperature distribution diagram when the cup-shaped grinding wheel of the present invention is ground.

[0033] Explanation of reference numerals: coated thermocouple 1; high-frequency temperature data collector 2; workpiece unit 3; gold-sprayed layer 4; copper metal layer 5; nickel metal layer 6; lead wire 7; mica sheet 8; computer software processing system 9; multi-channel oscilloscope 10; cup grinding wheel 11. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0035] See also Figure 1 The embodiment of the present application provides a method for measuring grinding temperature online by using a coating thermocouple, wherein a plurality of coating thermocouple temperature measuring units are used to measure the grinding temperature, each coating thermocouple temperature measuring unit comprises a coating thermocouple 1 and a high-frequency temperature data collector 2, and the coating thermocouple 1 is electrically connected to the high-frequency temperature data collector 2; the measuring process comprises the following steps:

[0036] Step 1, workpiece cutting and modification: Use a wire cutting machine to divide the workpiece to be ground into at least four workpiece units 3, and polish the side of each workpiece unit 3; the specific process is: clamp the workpiece to be ground on the wire cutting machine, cut the workpiece to be ground into blocks using the wire cutting machine under coolant conditions, and divide it into at least four workpiece units 3; use a planetary wheel polishing machine to polish the side of each workpiece unit 3, so that the side surface of the workpiece unit 3 is smooth, and the side edges of two workpiece units 3 can be tightly adhered during the gluing process;

[0037] Step 2, determine the installation position of the coating thermocouple: assemble the divided workpiece units 3 into the initial shape of the workpiece to be ground, determine the feed position, inlet position and outlet position of the cup-shaped grinding wheel on the cut workpiece to be ground, and the slit between two adjacent workpiece units 3 at the feed position, inlet position and outlet position is the installation position of the coating thermocouple 1; the specific determination process is: along the forward direction of the cup-shaped grinding wheel, the center position of the cup-shaped grinding wheel is the feed position of the grinding wheel, in the radial direction of the cup-shaped grinding wheel, the position corresponding to the left end grinding surface of the cup-shaped grinding wheel is the inlet position / outlet position, and the position corresponding to the right end grinding surface of the cup-shaped grinding wheel is the outlet position / inlet position;

[0038] Step 3, installing the coating thermocouple: a coating thermocouple 1 is arranged at the feeding position, the inlet position and the outlet position of the cup-shaped grinding wheel, and in the slit between two adjacent workpiece units 3; the specific arrangement process is:

[0039] Step 3.1, local gold spraying: gold spraying is performed at the position where the plated thermocouple 1 is to be installed and at the opposite surfaces of two adjacent workpiece units 3, and local gold spraying is performed using an ion sputtering apparatus, and gold ions are excited by high voltage and sputtered to the side surface of the workpiece unit 3. The area not sprayed with gold is shielded with a film, so that the gold spraying positions between the two adjacent workpiece units 3 are relatively set, so that the plated thermocouple 1 is only distributed at the local gold spraying position; the gold spraying operation is repeated for many times, and a uniform gold spraying layer 4 is formed until the side surface of the workpiece unit 3 reaches good conductivity, wherein the thickness of the gold spraying layer 4 is 3 to 7 um;

[0040] Step 3.2, electroplating and depositing a metal layer: electroplating and depositing the gold-sprayed workpiece unit 3 at room temperature using an electroplating device, and electroplating and depositing copper metal and nickel metal at the gold-sprayed positions between two adjacent workpiece units 3, that is, electroplating and depositing copper metal at the gold-sprayed position of one workpiece unit 3 to form a copper metal layer 5 on its surface, and electroplating and depositing nickel metal at the gold-sprayed position of the other workpiece unit 3 to form a nickel metal layer 6 on its surface, the thickness of the copper metal layer 5 and the nickel metal layer 6 are both 10 to 100 um; and the upper end surfaces of the copper metal layer 5 and the nickel metal layer 6 are flush with the surface of the workpiece to be ground;

[0041] Step 3.3, respectively make solder joints on the copper metal layer 5 and the nickel metal layer 6 at a position away from the grinding surface and connect the lead wires 7, the two lead wires 7 are led out from the side away from the grinding area, and a mica sheet 8 is inserted between the copper metal layer 5 and the nickel metal layer 6 to avoid signal interference. At this point, the plated thermocouple 1 is completed; connect the two lead wires to the positive and negative poles of a sensitive ammeter or a multimeter, respectively, and use a sensitive ammeter or a multimeter to test the quality of the solder joints and the lead wires to ensure good conductivity;

[0042] Step 4, workpiece bonding and measuring the conductivity of the coated thermocouple: bonding the cut workpiece unit 3, and measuring the conductivity of the coated thermocouple 1; the specific process is: applying glue to the side surfaces of two adjacent workpiece units 3 except the metal layer position, and the sides of the two adjacent workpiece units 3 are glued and fixed, and after the workpiece is glued and assembled into a workpiece to be ground, the conductivity of the coated thermocouple 1 is measured again by a multimeter to ensure good conductivity;

[0043] Step 5, calibration of the coating thermocouple: Calibrate the coating thermocouple 1 using a device with a relatively fixed temperature environment, such as a constant temperature oil tank or a constant temperature box. During the calibration process, a calibrated thermometer is used as a reference. The two leads of the coating thermocouple 1 are respectively connected to the positive and negative electrodes of the ammeter, and the corresponding currents at different temperatures are recorded in turn;

[0044] Step 6, online measurement: clamp the calibrated coated thermocouple workpiece in the grinding system, connect the lead wire to the current amplifier and then to the high-frequency temperature data collector 2, the high-frequency temperature data collector 2 transmits the collected data to the computer software processing system 9 and uses the multi-channel oscilloscope 10 to display the measurement signal in real time, so as to realize the online measurement of the grinding temperature.

[0045] In this embodiment, the current thermocouple gap temperature measurement method is generally to use purchased metal sheets for direct installation and production. On the one hand, the area of ​​the metal sheet is relatively large, and the coverage area is relatively large, so it is impossible to accurately measure the temperature of the grinding area; on the other hand, the metal sheet is relatively thick, resulting in a relatively large gap between the two workpiece units 3, which ultimately leads to incompleteness of the workpiece to be ground. However, this embodiment adopts the electroplating deposition method in the gap of the workpiece to be ground to make the thermocouple. Copper metal and nickel metal with a very small electroplating area can be used as needed. The temperature of the grinding area can be accurately measured, and the metal layer is thin, which can ensure the integrity of the workpiece. In addition, the installation positions of the thermocouples in this embodiment are selected from the feed position, inlet position and outlet position of the cup-shaped grinding wheel. The temperatures at these three positions can represent the surface grinding temperature. In the surface grinding temperature of the cup-shaped grinding wheel, the analytical calculation results are as follows: Figure 6 As shown, the temperature at the inlet and outlet is relatively high, while the temperature in the middle is low. This arrangement of thermocouples can reflect the grinding temperature.

[0046] In this embodiment, when bonding two workpiece units 3 together, no glue is applied at the location of the coated thermocouple 1, only glue is applied at the bonding surface of the workpiece unit 3, so the coated thermocouple 1 is not covered, so it is not affected by the external physical field and is more stable and durable.

[0047] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A method for measuring grinding temperature online using a coating thermocouple, characterized in that: The grinding temperature is measured by using multiple coating thermocouple temperature measuring units. Each coating thermocouple temperature measuring unit includes a coating thermocouple and a high-frequency temperature data collector. The coating thermocouple is electrically connected to the high-frequency temperature data collector. The measurement process is as follows: Step 1: Cutting and processing the workpiece: using a wire cutting machine to cut the workpiece to be ground into at least four workpiece units, and polishing the side of each workpiece unit; Step 2, determine the installation position of the coating thermocouple: assemble the divided workpiece units into the initial shape of the workpiece to be ground, determine the feed position, inlet position and outlet position of the cup-shaped grinding wheel on the cut workpiece to be ground, and the slit between two adjacent workpiece units at the feed position, inlet position and outlet position is the installation position of the coating thermocouple; Step 3, installing the coating thermocouple: a coating thermocouple is arranged at the feeding position, the inlet position and the outlet position of the cup grinding wheel, and in the slit between two adjacent workpiece units; Step 3.1, local gold spraying: using an ion sputtering device to locally spray gold on the side of the workpiece unit and at the position where the coating thermocouple is to be installed, using a high voltage to excite gold ions and sputter them onto the side surface of the workpiece unit, while making the gold spraying positions between two adjacent workpiece units relatively set; the gold spraying operation is repeated multiple times to form a conductive gold spraying layer; Step 3.2, electroplating and depositing metal layers: electroplating and depositing the gold-sprayed workpiece units at room temperature using an electroplating device, and electroplating and depositing a copper metal layer and a nickel metal layer at the gold-sprayed positions between two adjacent workpiece units, respectively, so that the upper end surfaces of the copper metal layer and the nickel metal layer are flush with the surface of the workpiece to be ground; Step 3.3, make solder joints and connect leads on the copper metal layer and the nickel metal layer at positions away from the grinding surface, respectively. The two leads are led out from the side away from the grinding area. At the same time, a mica sheet is inserted between the copper metal layer and the nickel metal layer to avoid signal interference; connect the two leads to the positive and negative poles of a sensitive ammeter or a multimeter, respectively, and use a sensitive ammeter or a multimeter to test the quality of the solder joints and leads to ensure good conductivity; Step 4, bonding the workpiece and measuring the conductivity of the coated thermocouple: bonding the cut workpiece units and measuring the conductivity of the coated thermocouple; Step 5, calibration of the coating thermocouple: use a device with a relatively fixed temperature environment to calibrate the coating thermocouple. During the calibration process, a calibrated thermometer is used as a reference. The two leads of the coating thermocouple are respectively connected to the positive and negative electrodes of the ammeter, and the corresponding currents at different temperatures are recorded in turn. Step 6, online measurement: Clamp the calibrated coated thermocouple workpiece into the grinding system, connect the lead wire to the current amplifier and then to the high-frequency temperature data collector. The high-frequency temperature data collector transmits the collected data to the computer software system and uses a multi-channel oscilloscope to display the measurement signal in real time, thereby realizing online measurement of the grinding temperature.

2. The method for measuring grinding temperature online by using a coating thermocouple according to claim 1, characterized in that: In the step 1, the specific operation process is: clamping the workpiece to be ground on the wire cutting machine, cutting the workpiece to be ground into blocks using the wire cutting machine under coolant conditions, and dividing it into at least four workpiece units; using a planetary wheel polishing machine to polish the side of each workpiece unit.

3. The method for measuring grinding temperature online by using a coating thermocouple according to claim 1, characterized in that: In step 2, the process of determining the installation position of the coated thermocouple is as follows: along the forward direction of the cup-shaped grinding wheel, the center position of the cup-shaped grinding wheel is the feeding position of the grinding wheel, in the radial direction of the cup-shaped grinding wheel, the position corresponding to the left end grinding surface of the cup-shaped grinding wheel is the import position / export position, and the position corresponding to the right end grinding surface of the cup-shaped grinding wheel is the export position / import position.

4. The method for measuring grinding temperature online by using a coating thermocouple according to claim 1, characterized in that: In the step 3.1, the thickness of the gold spraying layer is 3-7 um.

5. The method for measuring grinding temperature online by using a coating thermocouple according to claim 1, characterized in that: In the step 3.2, the thickness of the copper metal layer and the nickel metal layer is 10-100 um.

6. The method for measuring grinding temperature online by using a coating thermocouple according to claim 1, characterized in that: In the step 4, the specific operation process is: apply glue to the side surfaces of two adjacent workpiece units and, except for the metal layer position, the sides of the two adjacent workpiece units are pasted and fixed. After pasting and combining them into the workpiece to be ground, the conductivity of the coated thermocouple is measured again by a multimeter to ensure good conductivity.

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