CN108344357A - Medium-temperature resistance strain gauge and preparation method thereof - Google Patents

Abstract

The invention discloses a medium-temperature resistance strain gauge and a preparation method thereof, the medium-temperature resistance strain gauge comprises a polyether-ether-ketone film, polyimide glue and a circuit foil, the preparation of the medium-temperature resistance strain gauge is reasonable, each link can ensure the performance of the strain gauge, when the polyether-ether-ketone film with the polyimide glue thrown thereon is placed in an oven, the baking time is strictly controlled within 2-2.5 hours, the baking temperature is 38-40 ℃, the bending deformation of the polyether-ether-ketone film caused by overhigh temperature can be prevented, and the semi-finished product of the strain gauge is placed in a clamp when being laminated, the clamp is locked by a lock nut after being pressed by a press machine, when the whole clamp is placed in the oven for heating and curing, the same pressure state is still kept, the semi-finished product of the strain gauge can be stressed evenly, and the problem caused by uneven stress when the strain gauge is placed in a laminating machine for heating in the, the medium-temperature resistance strain gauge has stable performance, high quality and good temperature resistance.

Description

Medium temperature resistance strain gauge and preparation method thereof

technical field

The invention relates to the technical field of strain gauges, in particular to a medium-temperature resistance strain gauge and a preparation method thereof.

Background technique

With the rapid development of modern science and technology and the improvement of automation, resistance strain gauge measurement technology has been widely used. It not only has the advantages of high accuracy and easy long-distance transmission, but also can be used in high temperature, high Stress and strain measurements of structural members under special conditions. As a sensitive element, the resistance strain gauge can be made into various force measurement, pressure measurement, displacement and other sensors, and is widely used in industrial and scientific experiments.

Resistance strain gauges can be divided into normal temperature, medium temperature, high temperature and low temperature strain gauges according to the allowable working temperature range. Among them, whether the medium temperature resistance strain gauge can be developed mainly depends on three basic conditions: (1) The performance of the foil material and temperature resistance; (2) temperature resistance and performance of the strained base adhesive; (3) reasonable production process. .

Contents of the invention

The object of the present invention is to overcome the above-mentioned defects in the prior art, and provide a medium-temperature resistance strain gauge and a preparation method thereof.

In order to achieve the above object, the first aspect of the present invention provides a method for preparing a medium temperature resistance strain gauge, comprising the following steps:

S1. Fix the polyether ether ketone film on the glass plate, and evenly throw the polyimide glue onto the surface of the polyether ether ketone film through a glue spreader to achieve uniform gluing;

S2. Put the glued polyetheretherketone film into an oven and bake for 2 to 2.5 hours at a temperature of 38 to 40°C;

S3. Take out the baked polyetheretherketone film, and align and bond the glue surface of the polyetheretherketone film to the pre-prepared circuit foil to form a semi-finished strain gauge;

S4. Place the semi-finished strain gage in the fixture, preliminarily tighten all the lock nuts in the fixture, then place the fixture under the pressure head of the press, press the fixture with the press, and further tighten all the locks in the fixture with a wrench Fix the nut so that the clamp still maintains the same pressure state after it is removed;

S5. Put the jig with the semi-finished strain gauge into the oven for curing, raise the temperature from room temperature to 200-250°C, stop baking after 3 hours of heat preservation, and cool down to room temperature naturally to take it out;

S6. Unload all the locking nuts in the fixture, and take out the medium-temperature resistance strain gauge obtained after lamination and curing.

As preferably, after step S6, the following steps are also included:

S7. Grind the solder joints of the medium-temperature resistance strain gauge with a cotton ball soaked in glycerin/micropowder solution. After grinding, use a cotton ball soaked in alcohol to scrub the front and back of the medium-temperature resistance strain gauge, and then use acetone soaked Wipe the front and back of the medium temperature resistance strain gauge with a cotton ball, then wipe the front and back of the medium temperature resistance strain gauge with non-woven cloth or cotton, wipe clean and dry;

S8. Perform trimming, appearance inspection, sorting and packaging on the medium-temperature resistance strain gauges in sequence.

Preferably, the speed of the homogenizer is controlled at 1800-2000 rpm, and the time is 20-26 seconds; the pressure of the press is set at 650-700Kg.

As preferably, the preparation method of the circuit foil comprises the following steps:

S101. Photolithography: before photolithography, use gauze impregnated with absolute ethanol/micropowder solvent to polish and deoxidize the surface of the foil raw material to realize cleaning; use an antistatic brush to remove foreign matter on the surface of the cleaned foil raw material, And evenly throw the photoresist onto the surface of the foil material through the glue leveling machine; put the glued foil material into the oven for baking, rise from room temperature to 100°C, keep it warm for 18 to 20 minutes, and then stop baking baked, cooled to room temperature;

S102. Exposure: place the foil material after the photolithography step on the exposure sponge, attach the mask to the foil material, and send it into the exposure machine for exposure;

S103. Developing: Put the exposed foil material into a developing machine and develop it with a developing solution. The developing time is controlled at 18-22 seconds; after developing, it needs to be rinsed with water. Dry the surface with a hair dryer;

S104. Corrosion: put the developed foil material into the etching machine and corrode it with the corrosive solution to obtain the circuit foil material. The corrosion temperature is controlled at 40-50°C; after corrosion, put the circuit foil material into ammonia water for processing And treatment, the neutralization time is 3 to 4 seconds, then soak in clean water, the soaking time is within 3 minutes; put the neutralized circuit foil into the stripping solution and soak for 28 to 35 seconds, wait for photolithography After the glue is completely dissolved, take out the circuit foil and rinse it with a brush in clean water. After rinsing, dry it centrifugally on a water spinner. After drying, clean the front and back of the circuit foil with a cotton ball soaked in acetone.

Preferably, after the step S104, the following steps are also included:

S105. Semi-inspection: put the circuit foil material under a microscope for microscopic inspection. After the microscopic inspection, use a resistance meter to detect the resistance value of the qualified circuit foil material;

S106. Resistance adjustment: Use cotton balls soaked with glycerol/micropowder solution to adjust the resistance of the circuit foil whose resistance value does not meet the requirements.

As a preference, in step S101, the component distribution ratio in the absolute ethanol/fine powder solvent is 50ml absolute ethanol:10g fine powder.

As preferably, in step S4, the fixture includes a fixture bottom plate, a polytetrafluoro film, silicon rubber, a fixture glass plate, a fixture top plate, bolts and nuts for locking the fixture bottom plate and the fixture top plate, and the fixture assembly method It is: put two layers of PTFE film on the bottom plate of the fixture, then put a piece of silicon rubber, then put two layers of PTFE film, then put a semi-finished strain gauge, then put a fixture glass plate with aluminum foil on both sides, and then put Another semi-finished strain gauge, put two layers of PTFE film, then put a piece of silicon rubber, then put two layers of PTFE film, and so on in this order, the last version needs to place two pieces of silicon rubber, and then install the top plate of the fixture , Lock the bottom plate of the fixture and the top plate of the fixture through bolts and nuts.

As a preference, the component distribution ratio in the glycerol/micropowder solution is 10ml glycerol: 11g micropowder.

The second aspect of the present invention provides a medium temperature resistance strain gauge, including a polyether ether ketone film, a polyimide adhesive and a circuit foil, and the polyimide adhesive is located between the polyether ether ketone film and the circuit foil between.

Preferably, the polyether ether ketone film has a thickness of 18-20 μm, the polyimide adhesive has a thickness of 6-10 μm, and the circuit foil has a thickness of 3.8-5 μm.

Compared with prior art, the beneficial effect of the present invention is:

The preparation of the present invention is reasonable, and each link can guarantee the performance of the strain gauge. When the polyetheretherketone film is put into the oven after the polyimide glue is thrown, the baking time is strictly controlled at 2 to 2.5 hours. The temperature is 38-40°C, which can prevent the polyether ether ketone film from bending and deformation due to excessive temperature, and the semi-finished strain gauge is placed in the fixture during lamination, and the fixture is pressed by the press and locked by the lock nut. Tight fixture, when the whole fixture is put into the oven for heating and curing, it still maintains the same pressure state, which can make the strain gauge semi-finished product evenly stressed, avoiding the strain gauge placed in the laminator and laminating together in the traditional process. Due to the bad problem caused by uneven force, the medium temperature resistance strain gauge of the present invention has stable performance, high quality and good temperature resistance.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are For some embodiments of the present invention, those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a structural schematic diagram of a medium-temperature resistance strain gauge provided by the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Please refer to Fig. 1, an embodiment of the present invention provides a medium temperature resistance strain gauge, including a polyether ether ketone film 1, a polyimide glue 2 and a circuit foil 3, the polyimide glue 2 is located on the polyether Between the ether ketone film 1 and the circuit foil 2 .

In this embodiment, the thickness of the polyether ether ketone film can preferably be set to 18-20 μm, the thickness of the polyimide adhesive can be preferably set to 6-10 μm, and the thickness of the circuit foil can be preferably set to 3.8 to 5 μm.

In this embodiment, the preparation method of the medium temperature resistance strain gauge comprises the following steps:

S1. Fix the polyether ether ketone film (PEEK) on a clean glass plate, and evenly throw the polyimide glue onto the surface of the polyether ether ketone film through a glue spreader to achieve uniform gluing;

In step S1, the speed of the homogenizer is controlled at 1800-2000 rpm, and the time is 20-26 seconds. The polyether ether ketone film should be placed in the center of the turntable of the glue equalizer. After gluing, the glue layer should be even, without bubbles and lack of glue.

S2. Put the polyetheretherketone film after applying the polyimide glue into an oven, and bake for 2 to 2.5 hours at a temperature of 38 to 40°C;

When baking, the baking temperature should not be higher than 40°C, otherwise the polyether ether ketone film after gluing will bend and shrink, and the polyether ether ketone film will be scrapped directly.

S3. Take out the baked polyetheretherketone film, and align and bond the glue surface of the polyetheretherketone film to the pre-prepared circuit foil to form a semi-finished strain gauge;

S4. Put the semi-finished strain gage into the fixture, preliminarily tighten all the lock nuts in the fixture, then place the fixture under the pressure head of the press, set the pressure of the press to 650-700Kg, and press the fixture through the press , and further tighten all the lock nuts in the clamp with a wrench, so that the clamp still maintains the same pressure state after it is removed;

In step S4, the fixture includes a fixture bottom plate, a polytetrafluoro film, a silicon rubber, a fixture glass plate, a fixture top plate, bolts and nuts for locking the fixture bottom plate and the fixture top plate.

The fixture assembly method is as follows: put two layers of PTFE films on the bottom plate of the fixture, then put a piece of silicon rubber, then put two layers of PTFE films, then put a strain gauge semi-finished product (the base faces the aluminum foil), and then put a piece with two sides Fixture glass plate with aluminum foil, then put another semi-finished strain gauge (the base faces the aluminum foil), then put two layers of PTFE film, then put a piece of silicon rubber, then put two layers of PTFE film, and so on in this order , the last version needs to place two pieces of silicon rubber, and then install the top plate of the fixture. After the bottom layer is installed, the spring is loaded at the same time, and the bottom plate of the fixture and the top plate of the fixture are locked by bolts and nuts. Among them, the PTFE film, silicon rubber, and the glass plate of the fixture should be cleaned with alcohol non-woven cloth, and the surface should be free of particles, fiber hair, etc., and the aluminum foil should be flat and close to the glass plate of the fixture, without bumps, dust, etc.

S5. Put the jig with the semi-finished strain gauge into the oven for curing, raise the temperature from room temperature to 200-250°C, stop baking after 3 hours of heat preservation, and cool down to room temperature naturally to take it out;

S6. Unload all the locking nuts in the fixture, and take out the medium temperature resistance strain gauge made after lamination and curing;

When unloading the fixture, all lock nuts are required to be unloaded at the same time, and the strain gauges are removed in sequence. When removing the strain gauges, it should be ensured that there are no wrinkles and no mixed pieces.

S7. Grind the solder joints of the medium-temperature resistance strain gauge with a cotton ball soaked in glycerin/micropowder solution. After grinding, use a cotton ball soaked in alcohol to scrub the front and back of the medium-temperature resistance strain gauge, and then use acetone soaked Wipe the front and back of the medium temperature resistance strain gauge with a cotton ball, then wipe the front and back of the medium temperature resistance strain gauge with non-woven cloth or cotton, wipe clean and dry;

S8. Perform trimming, appearance inspection, sorting and packaging on the medium-temperature resistance strain gauges in sequence.

Wherein, the preparation method of the circuit foil comprises the following steps:

S101. Photolithography: Clean the foil raw material before photolithography, polish and deoxidize the surface of the foil raw material with gauze impregnated with absolute ethanol/fine powder solvent; clean the surface of the cleaned foil raw material with an antistatic brush Foreign matter, and evenly throw the photoresist onto the surface of the foil raw material through the glue leveler; put the glued foil raw material into the oven for baking, rise from room temperature to 100°C, and keep it warm for 18-20 minutes Then stop baking and cool to room temperature;

S102. Exposure: place the foil material after the photolithography step on the exposure sponge, attach the mask to the foil material, and send it into the exposure machine for exposure;

S103. Developing: Put the exposed foil material into a developing machine and develop it with a developing solution. The developing time is controlled at 18-22 seconds; after developing, it needs to be rinsed with water. Dry the surface with a hair dryer;

S104. Corrosion: put the developed circuit foil into an etching machine to corrode with the corrosion solution, the corrosion temperature is controlled at 40-50°C, and the circuit foil is obtained after corrosion; put the corroded circuit foil into the Neutralize in ammonia water, the neutralization time is 3-4 seconds, then soak in clean water, the soaking time is within 3 minutes; put the neutralized circuit foil into the stripping solution and soak for 28-35 seconds After the photoresist is completely dissolved, take out the circuit foil and rinse it with a brush in clean water. After rinsing, dry it centrifugally on a water spinner. cleaning;

S105. Semi-inspection: Put the circuit foil material under a microscope for microscopic inspection. After the microscopic inspection, use a resistance meter to perform resistance value detection on qualified circuit foil materials.

S106. Resistance adjustment: Use cotton balls soaked with glycerol/micropowder solution to adjust the resistance of the circuit foil whose resistance value does not meet the requirements.

In step S101, the component distribution ratio of the absolute ethanol/fine powder solvent is 50ml of absolute ethanol:10g of fine powder.

In step S7 and step S106, the component distribution ratio in the glycerol/micropowder solution is 10ml glycerol: 11g micropowder.

The preparation of the present invention is reasonable, and each link can guarantee the performance of the strain gauge. When the polyetheretherketone film is put into the oven after the polyimide glue is thrown, the baking time is strictly controlled at 2 to 2.5 hours. The temperature is 38-40°C, which can prevent the polyether ether ketone film from bending and deformation due to excessive temperature, and the semi-finished strain gauge is placed in the fixture during lamination, and the fixture is pressed by the press and locked by the lock nut. Tight fixture, when the whole fixture is put into the oven for heating and curing, it still maintains the same pressure state, which can make the strain gauge semi-finished product evenly stressed, avoiding the strain gauge placed in the laminator and laminating together in the traditional process. Due to the bad problem caused by uneven force, the medium temperature resistance strain gauge of the present invention has stable performance, high quality and good temperature resistance.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. a preparation method of medium temperature resistance strain gauge, is characterized in that, comprises the following steps: S1. Fix the polyether ether ketone film on the glass plate, and evenly throw the polyimide glue onto the surface of the polyether ether ketone film through a glue spreader to achieve uniform gluing; S2. Put the glued polyetheretherketone film into an oven and bake for 2 to 2.5 hours at a temperature of 38 to 40°C; S3. Take out the baked polyetheretherketone film, and align and bond the glue surface of the polyetheretherketone film to the pre-prepared circuit foil to form a semi-finished strain gauge; S4. Place the semi-finished strain gage in the fixture, preliminarily tighten all the lock nuts in the fixture, then place the fixture under the pressure head of the press, press the fixture with the press, and further tighten all the locks in the fixture with a wrench Fix the nut so that the clamp still maintains the same pressure state after it is removed; S5. Put the jig with the semi-finished strain gauge into the oven for curing, raise the temperature from room temperature to 200-250°C, stop baking after 3 hours of heat preservation, and cool down to room temperature naturally to take it out; S6. Unload all the locking nuts in the fixture, and take out the medium-temperature resistance strain gauge obtained after lamination and curing. 2. the preparation method of medium temperature resistance strain gauge according to claim 1, is characterized in that, also comprises the following steps after step S6: S7. Grind the solder joints of the medium-temperature resistance strain gauge with a cotton ball soaked in glycerin/micropowder solution. After grinding, use a cotton ball soaked in alcohol to scrub the front and back of the medium-temperature resistance strain gauge, and then use acetone soaked Wipe the front and back of the medium temperature resistance strain gauge with a cotton ball, then wipe the front and back of the medium temperature resistance strain gauge with non-woven cloth or cotton, wipe clean and dry; S8. Perform trimming, appearance inspection, sorting and packaging on the medium-temperature resistance strain gauges in sequence. 3. the preparation method of medium-temperature resistance strain gauge according to claim 1 is characterized in that, the rotating speed control of described glue homogenizer is 1800～2000 rev/min, and the time is 20～26 seconds; Set to 650 ~ 700Kg. 4. the preparation method of medium temperature resistance strain gauge according to claim 1, is characterized in that, the preparation method of described circuit foil comprises the following steps: S101. Photolithography: before photolithography, use gauze impregnated with absolute ethanol/micropowder solvent to polish and deoxidize the surface of the foil raw material to realize cleaning; use an antistatic brush to remove foreign matter on the surface of the cleaned foil raw material, And evenly throw the photoresist onto the surface of the foil material through the glue leveling machine; put the glued foil material into the oven for baking, rise from room temperature to 100°C, keep it warm for 18 to 20 minutes, and then stop baking baked, cooled to room temperature; S102. Exposure: place the foil material after the photolithography step on the exposure sponge, attach the mask to the foil material, and send it into the exposure machine for exposure; S103. Developing: Put the exposed foil material into a developing machine and develop it with a developing solution. The developing time is controlled at 18-22 seconds; after developing, it needs to be rinsed with water. Dry the surface with a hair dryer; S104. Corrosion: put the developed foil material into the etching machine and corrode it with the corrosive solution to obtain the circuit foil material. The corrosion temperature is controlled at 40-50°C; after corrosion, put the circuit foil material into ammonia water for processing And treatment, the neutralization time is 3 to 4 seconds, then soak in clean water, the soaking time is within 3 minutes; put the neutralized circuit foil into the stripping solution and soak for 28 to 35 seconds, wait for photolithography After the glue is completely dissolved, take out the circuit foil and rinse it with a brush in clean water. After rinsing, dry it centrifugally on a water spinner. After drying, clean the front and back of the circuit foil with a cotton ball soaked in acetone. 5. the preparation method of medium temperature resistance strain gauge according to claim 4, is characterized in that, also comprises the following steps after described step S104: S105. Semi-inspection: put the circuit foil material under a microscope for microscopic inspection. After the microscopic inspection, use a resistance meter to detect the resistance value of the qualified circuit foil material; S106. Resistance adjustment: Use cotton balls soaked with glycerol/micropowder solution to adjust the resistance of the circuit foil whose resistance value does not meet the requirements. 6 . The method for preparing a medium-temperature resistance strain gauge according to claim 4 , characterized in that, in step S101 , the component ratio in the absolute ethanol/micropowder solvent is 50ml of absolute ethanol: 10g of micropowder. 7. The preparation method of medium temperature resistance strain gauge according to claim 1, is characterized in that, in step S4, described fixture comprises fixture bottom plate, polytetrafluoro film, silicon rubber, fixture glass plate, fixture top plate, for Lock the bolts and nuts on the bottom plate of the fixture and the top plate of the fixture. The assembly method of the fixture is as follows: put two layers of PTFE film on the bottom plate of the fixture, then put a piece of silicon rubber, then put two layers of PTFE film, and then put a strain To measure the semi-finished product, put a clamp glass plate with aluminum foil on both sides, then put another semi-finished strain gauge, then put two layers of PTFE film, then put a piece of silicon rubber, and then put two layers of PTFE film, in this order By analogy, the last version needs to place two pieces of silicon rubber, then install the fixture top plate, and lock the fixture bottom plate and fixture top plate through bolts and nuts. 8. The preparation method of the medium temperature resistance strain gauge according to claim 2 or 5, characterized in that, the component distribution ratio in the glycerol/micropowder solution is 10ml glycerol:11g micropowder. 9. A medium temperature resistance strain gauge, characterized in that it comprises a polyether ether ketone film, a polyimide glue and a circuit foil, and the polyimide glue is located between the polyether ether ketone film and the circuit foil. 10. The medium temperature resistance strain gauge according to claim 9, characterized in that, the polyetheretherketone film has a thickness of 18-20 μm, the polyimide glue has a thickness of 6-10 μm, and the circuit foil The thickness of the material is 3.8-5 μm.