Method for pasting resistance strain gauge on resistance strain sensor

Abstract

The invention belongs to the technical field of measurement and control, and particularly relates to a method for pasting a resistance strain gauge on a resistance strain sensor. The pasting method comprises the following working procedures of preparation work before pasting, test piece polishing treatment, cleaning, adhesive coating, pressing and curing, test line fixing and checking. The method for pasting the resistance strain gauge on the resistance strain sensor provided by the invention is suitable for the measurement technology of C3 and above high-precision sensors, realizes operation standardization, and improves the pasting quality of the resistance strain gauge of the sensor by using a rigorous and clear process method; therefore, the strain transmission efficiency of the resistance strain gauge during the sensor testing work is improved.

Description

Technical Field

[0001] The invention belongs to the field of measurement and control technology, and in particular relates to a method for pasting a resistance strain gauge on a resistance strain sensor. Background Art

[0002] Sensor technology is the sensory organ of information systems and an indispensable part of automatic control technology and automatic detection technology. The development of modern science and technology is highly dependent on sensor technology, and the accuracy of sensor test data is crucial to signal conversion and information processing.

[0003] Resistance strain sensors are widely used in aviation, aerospace, and ship fluid mechanics experiments due to their high measurement accuracy, good frequency response, and strong environmental adaptability. Resistance strain sensors convert force into strain through metal elastic bodies. Under the action of external forces, the elastic body transmits the generated strain to the sensitive grid of the resistance strain gauge through the patch adhesive, which will cause the sensitive grid to deform and the resistance of the resistance strain gauge to change. According to the change in resistance value, the size of the external load can be measured. Therefore, in order to improve the accuracy of sensor measurement data, the bonding process technology of the resistance strain gauge plays a key role in the performance of the resistance strain sensor. Summary of the invention

[0004] The purpose of the present invention is to provide a method for pasting a resistance strain gauge on a resistance strain sensor. The pasting method has a complete process, rigorous description, and a combination of text and pictures. It is mainly suitable for the pasting process of a strain gauge with a self-contained substrate. This method is used as a guiding document for the pasting process of the resistance strain gauge to complete the pasting of the resistance strain gauge on the high-precision resistance strain sensor, which can ensure the excellent performance and long-term stability of the high-precision resistance strain sensor.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] A method for pasting a resistance strain gauge on a resistance strain sensor comprises the following steps:

[0007] (1) Preparation before patching: prepare the tools and materials used in patching;

[0008] (2) Specimen polishing: polish the surface of the specimen where the resistance strain gauge is to be mounted;

[0009] (3) Cleaning: Use organic solvents to clean the specimen surface and tools;

[0010] (4) Applying adhesive: applying adhesive to the location where the patch is to be placed;

[0011] (5) Press curing: Cover with polytetrafluoroethylene film, fix the resistance strain gauge and use a clamp to cure;

[0012] (6) Fixing the test wire: Use a soldering iron to solder the resistance strain gauge wire. There are two methods: setting the lead terminal and not setting the lead terminal;

[0013] (7) Inspection: Check the quality of the adhesive layer, resistance value of the strain gauge, and insulation resistance.

[0014] Preferably, the process (1) is divided into the following steps:

[0015] (1.1) Working environment inspection: Relative humidity should be maintained within the range of 30% to 50%, and temperature should be maintained within the range of 18℃ to 28℃; operators should wear work clothes, gloves and hats correctly, and bare-handed operation is prohibited;

[0016] (1.2) Tools and materials preparation: Tools and materials include terminal blocks, test pieces, solvents, cotton wool, electric soldering irons, solder, sandpaper, markers, tweezers, special glue pens, extension leads, multimeters, and magnifying glasses;

[0017] (1.3) Adhesive preparation: Prepare the adhesive according to the instructions for use and use it within the required period after preparation;

[0018] (1.4) Strain gauge inspection: Check the appearance and resistance value of the resistance strain gauge. The selected resistance strain gauge must not have bubbles, and the resistance wire grid on the resistance strain gauge must not have mold spots or rust spots. The resistance value must be within the range calibrated in the factory manual. Handle it with care during operation.

[0019] Further preferably, the adhesive is selected from corresponding epoxy resin glue, epoxy-phenolic glue or phenolic resin glue according to the material and temperature characteristics of the specimen.

[0020] Preferably, the step (2) is divided into the following steps:

[0021] (2.1) Before polishing, use a marker to mark the location of the patch. The polishing area should be larger than the base area of ​​the resistance strain gauge and expand around the location of the patch.

[0022] (2.2) Use 180-320 grit sandpaper to grind the location where the patch is to be placed into a cross pattern at an angle of 45° to the direction of the patch.

[0023] More preferably, in step (2.1), the polishing area is 8 to 10 times the area of ​​the base of the resistance strain gauge.

[0024] Preferably, the step (3) is divided into the following steps:

[0025] (3.1) Use cotton wool dipped in a small amount of acetone or carbon tetrachloride to clean the area where the patch is to be applied until the cotton wool does not change its original white color;

[0026] (3.2) Use anhydrous ethanol to clean the tools, polytetrafluoroethylene film and the strain gauge to be attached.

[0027] Preferably, the step (4) is divided into the following steps:

[0028] (4.1) Confirm that the strain gauge has been inspected and cleaned, confirm the location to be mounted, and confirm that the location to be mounted has been polished and cleaned;

[0029] (4.2) Apply a layer of adhesive to the position where the resistance strain gauge is to be mounted on the surface of the specimen and the adhesive surface of the resistance strain gauge base. The coating area of ​​the position where the resistance strain gauge is to be mounted is 3 to 5 mm in length and width, respectively, on the basis of the adhesive surface of the strain gauge base. After coating, leave it to air for a period of time;

[0030] (4.3) Use tweezers to align the resistance strain gauge with the patch positioning line and stick it to the location where the patch is to be mounted.

[0031] Preferably, the step (5) is divided into the following steps:

[0032] (5.1) Cover the resistance strain gauge with a polytetrafluoroethylene film, fix the resistance strain gauge and press it hard with the thumb to squeeze out the excess adhesive and bubbles along the axis of the resistance strain gauge;

[0033] (5.2) Upper fixture curing: Use the fixture to pressurize and heat the curing twice.

[0034] Preferably, if a lead terminal is provided, the step (6) is divided into the following steps:

[0035] (6.1) Pull up the lead wire: After curing is completed, remove the polytetrafluoroethylene film and carefully remove the excess adhesive around the strain gauge; pull up the end of the resistance strain gauge lead wire, being careful not to break the lead wire. Use tweezers to fix the lead wire close to the solder joint;

[0036] (6.2) Paste the terminal block: Paste the terminal block 3 to 5 mm away from the resistance strain gauge (the pasting method can refer to step (4));

[0037] (6.3) Welding of lead wires and wires: Use a constant temperature soldering iron to place the lead wire above the terminal block, and use an electric soldering iron and solder wire to firmly weld the lead end of the resistance strain gauge to the wire. Pay attention to keeping the lead wire loose to prevent the lead wire from being broken after the specimen is subjected to force.

[0038] If lead terminals are not provided, such as the strain gauge attached has its own terminals or the product structure does not require wiring terminals, the above steps can be omitted and the resistance strain gauge wire can be directly soldered using an electric soldering iron.

[0039] Further preferably, the temperature setting range of the constant temperature soldering iron is (265±10)°C.

[0040] Compared with the prior art, the beneficial effects of the present invention are at least:

[0041] 1) The present invention provides a method for pasting a resistance strain gauge on a resistance strain sensor, and during the operation, the excess material is strictly controlled, including pre-painting inspection, pre-gluing inspection and final inspection, so as to reduce the influence of surface contamination on the bonding strength of the adhesive;

[0042] 2) The method for pasting a resistance strain gauge on a resistance strain sensor provided by the present invention puts forward requirements for the working environment, and solves the problem that the moisture content of the adhesive changes due to the change of humidity in the air in the existing process, and the moisture absorption affects the internal stress of the adhesive and affects the bonding strength;

[0043] 3) In a method for pasting a resistance strain gauge on a resistance strain sensor provided by the present invention, the temperature range of the soldering iron used in the welding process is preferably (265±10)°C, which can reduce the heat generated in the welding process of the existing process and prevent the heat from being transferred to the soldering points of the lead wires and the wire grid and burning off the lead wires of the strain gauge;

[0044] 4) The method for pasting a resistance strain gauge on a resistance strain sensor provided by the present invention is suitable for high-precision sensor measurement technology of level C3 and above, realizes operation standardization, and improves the pasting quality of the sensor resistance strain gauge with a rigorous and clear process method, thereby improving the strain transfer efficiency of the resistance strain gauge during sensor testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the resistance strain gauge pasted on the surface of the specimen in Example 1; wherein 1 is a covering layer, 2 is a substrate, 3 is a specimen, 4 is a lead wire, 5 is patch glue, and 6 is a metal resistance wire grid.

[0046] Figure 2 Schematic diagram of the grinding process of the specimen in Example 1.

[0047] Figure 3 This is a schematic diagram of press curing in Example 1. DETAILED DESCRIPTION

[0048] For a better understanding of the present invention, the present invention is further described in detail below in conjunction with embodiments, but the scope of protection claimed by the present invention is not limited to the scope represented by the embodiments.

[0049] The raw materials used in the present invention, unless otherwise specified, are all conventional commercially available products. The methods used in the present invention, unless otherwise specified, are all conventional methods in the art. The quality of each substance used in the present invention is the conventional quality.

[0050] Example 1

[0051] In this embodiment, the test piece uses TC4-R material as the elastic body, the adhesive uses a two-component epoxy resin adhesive, and the resistance strain gauge uses a film-based strain gauge. The schematic diagram after the resistance strain gauge is attached to the surface of the test piece is shown in FIG. Figure 1 , where 1 is the covering layer, 2 is the substrate, 3 is the test piece, 4 is the lead wire, 5 is the patch adhesive, and 6 is the metal resistance wire grid.

[0052] The specific pasting method is as follows:

[0053] 1. Preparation before patching:

[0054] (1.1) Environmental requirements: Ambient temperature: Indoor relative humidity should be maintained within the range of 30% to 50%, and indoor temperature should be maintained within the range of 18℃ to 28℃; operators should wear work clothes, gloves and hats as required, and bare-handed operation is prohibited.

[0055] (1.2) Preparation of tools and auxiliary materials: Before SMT, the necessary tools and materials should be prepared in advance, including terminal blocks, test pieces, solvents, cotton wool, electric soldering irons, solder, sandpaper, markers, tweezers, special glue pens, extension leads, multimeters, and magnifying glasses.

[0056] (1.3) Adhesive preparation: According to the instructions for use of the adhesive, place the adhesive at the required temperature in advance and prepare it according to the proportion. Note that it should be used within the required period after preparation.

[0057] (1.4) Strain gauge inspection: Use a magnifying glass and anti-static tweezers to inspect on a clean operating platform: The selected resistance strain gauge should not have bubbles, and the resistance wire grid on the resistance strain gauge should not have mildew spots or rust spots; the base and cover layer should not be damaged or wrinkled. After determining that there is no appearance as described above, conduct a resistance inspection. Use the resistance range of a multimeter and touch the lead end of the strain gauge with the probe to conduct a resistance inspection: The resistance value is within the range specified in the factory manual. Be careful to handle with care during operation. Check that the number of strain gauges is 50% more than the actual number to be pasted.

[0058] 2. Specimen polishing: polish the patch position;

[0059] (2.1) Before polishing, use a marker to mark the pre-mounted area. The polishing area should be larger than the base area of ​​the strain gauge and expand in all directions along the pasting position. The polishing area should be 8 to 10 times the base area of ​​the strain gauge.

[0060] (2.2) Figure 2 As shown, a grinding method is selected. According to the specimen material, 180-320 grit sandpaper is selected to grind the patch area into a cross pattern at 45° to the force direction. During the grinding process, attention is paid to ensuring the flatness of the specimen surface.

[0061] 3. Cleaning:

[0062] (3.1) Use cotton wool dipped in a small amount of acetone or carbon tetrachloride to clean the area to be pasted, clean the surface oil and non-profitable particles, until the cotton wool does not change its original white color;

[0063] (3.2) Use anhydrous ethanol to clean the tools, polytetrafluoroethylene film and the strain gauge to be attached.

[0064] 4. Apply adhesive:

[0065] (4.1) Confirm that the strain gauge has been inspected and cleaned, that the pasting position and direction are correct, and that the pre-pasting position has been polished and cleaned.

[0066] (4.2) Apply a thin layer of adhesive evenly on the part of the specimen to be attached and the strain gauge base, with the length and width extending 3 to 5 mm from the adhesive surface of the strain gauge base, and let the adhesive dry for 2 minutes;

[0067] (4.3) Use special tweezers to align the resistance strain gauge with the patch positioning line and stick it to the test site.

[0068] 5. Press to cure:

[0069] (5.1) Figure 3 As shown in the figure, cover with polytetrafluoroethylene film, fix the strain gauge and press it hard with the thumb, while adjusting the pasting direction until it is correct, and squeeze out the excess glue and bubbles along the axial direction of the strain gauge;

[0070] (6.2) Upper fixture curing: curing is carried out in two steps, with pressurization and temperature increase.

[0071] The two curing processes are as follows: heating from room temperature to a first insulation temperature at a rate of about 2°C per minute, insulation for 2 hours, and cooling to room temperature in an oven; and secondary curing: heating to a second insulation temperature at the same rate after pressure relief, insulation for 2 hours, and cooling to room temperature.

[0072] 6. Test line fixing: There are two methods: setting lead terminals and not setting lead terminals. If the strain gauge lead is long or the product structure does not require a terminal, this step can be omitted.

[0073] (6.1) Pull up the lead: After curing is complete, remove the polytetrafluoroethylene film and carefully remove the excess glue around the strain gauge. Pull up the end of the strain gauge lead, being careful not to break the lead. Use tweezers to hold the lead close to the solder joint;

[0074] (6.2) Gluing the terminal block: Refer to step (4) and glue the terminal block 3 to 5 mm away from the strain gauge;

[0075] (6.3) For welding of leads and wires, set the temperature of the constant temperature soldering iron to 265±10℃, tin the wires for 4mm, and then apply a little solder to the terminals. Clamp the strain gauge leads with tweezers, place the leads above the terminals, press the tinned wires onto the leads and terminals, add solder, and use an electric soldering iron to firmly weld the strain gauge lead ends and wires together. The root of the lead weld should not be close to the plane, but should be in a relaxed state of an arc to prevent the lead from being broken after the specimen is subjected to force.

[0076] 7. Inspection: Check the quality of the adhesive layer, resistance value of the resistance strain gauge, and insulation resistance.

[0077] (7.1) Use a magnifying glass to check the quality of the adhesive layer and check whether there are bubbles, warping, debonding, etc. between the strain gauge and the specimen;

[0078] (7.2) Use the resistance range of a multimeter to test whether the resistance value of the resistance strain gauge is consistent with that before pasting and record it. If there is a change, remove it and paste it again;

[0079] (7.3) Use a multimeter to test the insulation resistance between the strain gauge and the specimen and it should be above 50MΩ.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for pasting a resistance strain gauge on a resistance strain sensor, characterized in that: Including the following processes: (1) Preparation before patching: prepare the tools and materials used in patching; (2) Specimen polishing: polish the surface of the specimen where the resistance strain gauge is to be mounted; (3) Cleaning: Use organic solvents to clean the specimen surface and tools; (4) Applying adhesive: applying adhesive to the location where the patch is to be placed; (5) Press curing: Cover with polytetrafluoroethylene film, fix the resistance strain gauge and use a clamp to cure; (6) Fixing the test wire: Use a soldering iron to solder the resistance strain gauge wire. There are two methods: setting the lead terminal and not setting the lead terminal; (7) Inspection: Check the quality of the adhesive layer, resistance value of the strain gauge, and insulation resistance.

2. The method for pasting a resistance strain gauge on a resistance strain sensor according to claim 1, characterized in that: The process (1) is divided into the following steps: (1.1) Working environment inspection: Relative humidity should be maintained within the range of 30% to 50%, and temperature should be maintained within the range of 18℃ to 28℃; operators should wear work clothes, gloves and hats correctly, and bare-handed operation is prohibited; (1.2) Tools and materials preparation: Tools and materials include terminal blocks, test pieces, solvents, cotton wool, electric soldering irons, solder, sandpaper, markers, tweezers, special glue pens, extension leads, multimeters, and magnifying glasses; (1.3) Adhesive preparation: Prepare the adhesive according to the instructions for use and use it within the required period after preparation; (1.4) Strain gauge inspection: Check the appearance and resistance value of the resistance strain gauge. The selected resistance strain gauge must not have bubbles, and the resistance wire grid on the resistance strain gauge must not have mold spots or rust spots. The resistance value must be within the range specified in the factory manual. Handle the strain gauge with care during operation.

3. A method for pasting a resistance strain gauge on a resistance strain sensor according to claim 1 or 2, characterized in that: The process (2) is divided into the following steps: (2.1) Before polishing, use a marker to mark the location of the patch. The polishing area should be larger than the base area of ​​the resistance strain gauge and expand around the location of the patch. (2.2) Use 180-320 grit sandpaper to grind the location where the patch is to be placed into a cross pattern at an angle of 45° to the direction of the patch.

4. A method for pasting a resistance strain gauge on a resistance strain sensor according to claim 1 or 2, characterized in that: The process (3) is divided into the following steps: (3.1) Use cotton wool dipped in a small amount of acetone or carbon tetrachloride to clean the area where the patch is to be applied until the cotton wool does not change its original white color; (3.2) Use anhydrous ethanol to clean the tools, polytetrafluoroethylene film and the strain gauge to be attached.

5. The method for pasting a resistance strain gauge on a resistance strain sensor according to claim 1 or 2, characterized in that: The process (4) is divided into the following steps: (4.1) Confirm that the strain gauge has been inspected and cleaned, confirm the location to be mounted, and confirm that the location to be mounted has been polished and cleaned; (4.2) Apply a layer of adhesive to the position where the resistance strain gauge is to be mounted on the surface of the specimen and the adhesive surface of the resistance strain gauge base. The coating area of ​​the position where the resistance strain gauge is to be mounted is 3 to 5 mm in length and width, respectively, on the basis of the adhesive surface of the strain gauge base. After coating, leave it to air for a period of time; (4.3) Use tweezers to align the resistance strain gauge with the patch positioning line and stick it to the location where the patch is to be mounted.

6. A method for pasting a resistance strain gauge on a resistance strain sensor according to claim 1 or 2, characterized in that: The process (5) is divided into the following steps: (5.1) Cover the resistance strain gauge with a polytetrafluoroethylene film, fix the resistance strain gauge and press it hard with the thumb to squeeze out the excess adhesive and bubbles along the axis of the resistance strain gauge; (5.2) Upper fixture curing: Use the fixture to pressurize and heat the curing twice.

7. A method for pasting a resistance strain gauge on a resistance strain sensor according to claim 1 or 2, characterized in that: If lead terminals are provided, the process (6) is divided into the following steps: (6.1) Pull up the lead wire: After curing is completed, remove the polytetrafluoroethylene film and carefully remove the excess adhesive around the strain gauge; pull up the end of the resistance strain gauge lead wire, being careful not to break the lead wire. Use tweezers to fix the lead wire close to the solder joint; (6.2) Paste the terminal: Paste the terminal 3 to 5 mm away from the resistance strain gauge; (6.3) Welding of lead wires and wires: Use a constant temperature soldering iron to place the lead wire above the terminal block, and use an electric soldering iron and solder wire to firmly weld the lead end of the resistance strain gauge to the wire. Pay attention to keeping the lead wire loose to prevent the lead wire from being broken after the specimen is subjected to force.

8. The method for pasting a resistance strain gauge on a resistance strain sensor according to claim 7, characterized in that: The temperature setting range of the constant temperature soldering iron is (265±10)°C.

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