This article mainly describes in detail the various aspects of tensile test machine knowledge.
Tensile testing machine, also known as universal testing machine,tensile tester,tensile test equipment. tensile testing machine is used for a variety of materials for equipment, static load, stretching, compression, bending, cutting, tearing, stripping and other mechanical properties of the test with the mechanical afterburner testing machine for plastic sheet, pipe, All kinds of physical and mechanical properties of materials such as rubber, wire and cable, steel wire, glass fiber and other materials for the development of materials for physical testing, teaching research, quality control and other indispensable testing equipment, tensile fixture as the instrument Important components, different materials require different fixtures, but also the test can be carried out smoothly and the accuracy of the test results of an important factor in the level.
Tensile testing machine test object
Servo tensile testing machines is mainly used for metal and non-metallic materials testing, such as rubber, plastic, wire and cable, fiber optic cable, seat belts, insurance belts, leather belt composite materials, plastic profiles, waterproofing membrane, Spring steel, bearing steel, stainless steel (and other high hardness steel), castings, steel, steel, non-ferrous metal wire drawing, compression, bending, cutting, stripping, tearing, two extension Count) and other tests.
The main features of the tensile testing machine
The use of imported electronic encoder for tension displacement measurement, the controller uses embedded single-chip microcomputer structure, built-in powerful control software, set measurement, control, computing, storage functions in one. Automatic calculation of stress, elongation (with extension), tensile strength, elastic modulus of the function, automatic statistical results; automatically record the maximum point, breaking point, the specified point of the force or elongation; the use of computer test Process and test curve of the dynamic display, and data processing, after the end of the test can be through the graphics processing module to re-analyze the data re-editing, and print statements.
Tensile testing machine application industry
tensile test machine widely used in metering quality inspection;such as rubber and plastics; metallurgical steel; machinery manufacturing; electronic appliances; automobile production; textile chemical fiber; wire and cable; packaging materials and food; instrumentation; medical equipment; civilian nuclear energy; civil aviation; Laboratory; commodity inspection arbitration, technical supervision departments; building materials ceramics; petrochemical; other industries.
Tensile testing machine classification
First, according to the level of automation can be divided into
1. Index-type tensile testing machine: This traditional tensile testing machine due to low test accuracy, low cost, has been basically a few digital tensile testing machine eliminated. But in the small power range, is our common rally, often used by small factories for the simple strength of the test, because of its low price, or popular.
2. Digital tensile testing machine, also known as microcomputer-based tensile testing machine: test data directly on the LCD screen, the test items are relatively fixed, commonly used in factory quality control.
3. Computer system Tensile testing machine is the most common tensile testing machine, the test data collected through the computer, and then through the software program to calculate the user to get the final data, and can be printed out by way of the report. Commonly used in scientific research units, testing agencies, new product development.
Second, according to the control system can be divided into
1. Frequency conversion system tension testing machine: the use of variable frequency motor control system, stretching, compression speed control by the frequency converter.
2. Servo system tension testing machine: the use of servo motor control system, stretching, compression speed and displacement control more accurate. Servo motor system for the servo control system, the use of intelligent feedback type operation, you can speed test, cycle testing, programming and testing.
3. Other drive method Rally testing machine: through the DC motor control, the drive method of tensile testing machine due to low cost, has been gradually eliminated.
Third, according to industry and functional characteristics can be divided into 1. Metal tensile testing machine: metal material tensile strength, elongation is small, need to configure the metal punctuation meter.
2. Rubber tensile testing machine: rubber or elastomer elongation is relatively large, with a large punctuation extension device, while the fixture design to consider the characteristics of rubber, can not slip. Can be equipped with O-ring fixture, tire industry, such as fixtures.
3. Plastic tensile testing machine: plastic tensile strength than rubber, elongation is very small, and often to test three-point bending test.
4. Textile tensile testing machine: the textile industry needs to test fabric fabric stripping, puncture, tearing, single yarn stretch test, fixture and software is special.
5. Paper tension testing machine: paper needs to test the tensile strength, ring pressure, vertical pressure, flat pressure, edge pressure, peel strength, fixture more.
6. Leather tensile testing machine: leather need to test the tensile strength, tear strength, test items is relatively simple.
Fourth, according to the test material points: metal fixture and non-metallic materials fixture;
5, according to the test temperature points: temperature fixture, high temperature fixture, low temperature fixture, high and low temperature fixture;
Six, according to the use of points: stretch fixture, compression fixture, bending fixture, shear fixture, stripping fixture, tearing fixture, sealing fixture, bending bending fixture;
Seven, according to the degree of automation points: manual fixture, pneumatic fixture, electric fixture, hydraulic fixture;
Tensile testing machine measurement principle
1, the tensile force test is measured by the force sensor, amplifier and data processing system to complete the measurement. It is known from the information mechanics that under the premise of small deformation, the strain ε of a certain elastic element is proportional to the force of the elastic element and is proportional to the elasticity of the elastic element. In the S-type testing machine sensor, for example, when the sensor is subjected to the effect of pulling force P, since the strain gauges are attached to the outer surface of the elastic member, the strain gauges are connected to the measuring circuit because the strain of the elastic member is proportional to the magnitude of the external force P , Can be measured by its output voltage, and then measure the size of the force.
2, deformation measurement measured by deformation measurement to measure, it is used to measure the sample in the experimental process occurred in the deformation. There are two chucks on the installation, which are connected with the photoelectric encoder mounted on the top of the measurement installation. When the interval between the two chucks changes, the axis of the photoelectric encoder is twisted, and the photoelectric coding There will be pulse signal output. And then by the processor to deal with this signal, you can get the deformation of the sample.
3, the beam displacement measurement of the same reason with the deformation of the same measurement, are measured by the number of optical encoder output pulse to obtain the amount of displacement of the beam.
First, the tensile test machine when the load, the pointer to stop or stop when walking
1, clutch gear wear: need to repair or replace.
2, friction plate leather washer or spring wear: need to replace the leather washer or spring.
3, the handle handle shift: adjust the joystick, so that with the alveolar with good.
Second, replace the pendulum when the pointer does not return to zero
1, tensile testing machine is not installed: the level of the test machine to adjust the level.
2, pendulum is not vertical: only hanging A mound. Adjust the balance mound to make it vertical.
Third, the tensile test machine pendulum back too fast or too slow
1, the buffer valve position placed improperly: adjust the buffer valve to the appropriate location.
2, the hydraulic oil viscosity is too low or too high: hydraulic oil viscosity is too low when the pendulum down fast, slow down when the slow slow. Replace the appropriate viscosity of the hydraulic oil.
3, the buffer valve, tubing or hydraulic oil is dirty: cleaning buffer valve, tubing. Replace the hydraulic oil.
Fourth, the tensile test machine back to zero or instability
1, the needle bearing, spindle bearing corrosion or oil: cleaning or replacement of bearings.
2, tooth rod deformation or gear and gear does not engage: straightening gear or cleaning, repair gear, sheave and other transmission parts.
3, the buffer valve is dirty: cleaning buffer valve.
Fifth, the tensile test machine shows positive deviation
1, short arm blade is loose: the blade firmly.
2, swing mound partial light: to the mound weight (to take into account the weight of A, B, C mound).
Six, showing the negative deviation of the main reason is the friction between the components of the excessive resistance
1, the needle bearings, pendulum shaft bearings and force transmission parts frictional resistance is too large: the main adjustment, cleaning bearings and force transmission components. Eliminate abnormal frictional resistance.
2, the upper chuck, driven spring spring tension and depiction of the frictional resistance of the device: adjust the upper chuck, driven spring spring tension and depiction device components. Eliminate abnormal frictional resistance.
3, the piston rod and pendulum parts are not flexible: adjust the two parts connected. Make it flexible.
Seven, driven by the hindrance or displacement
1, the effect of the elastic force of the driven spring or the magnitude of the frictional resistance of the driven needle and the indicating plate: adjust the elastic force of the driven spring spring or the gap of the driven needle and the indicating plate.
2, from the needle at both ends of the weight of a deviation: adjust the weight at both ends, to balance.
Eight, showing an irregular deviation
1, tooth rod, gear oil, wear or burr: eliminate the gear, gear oil, burr, find out when the tooth contact angle, and then correct the gear, gear; if you can not eliminate the error. Replace the gear bar, gear.
2, tensile testing machine installation is not level: adjust the level.
3, tooth rod bending: straighten or replace the gear, adjust the gap of the rolling wheel.
Nine, the computer software appears after the message box appears to display overload.
The solution is to check if the communication line between the computer and the test machine is off; check whether the online selection sensor is selected correctly; check the nearest test or operation key
Check whether the software has been calibrated or calibrated before the problem occurs; check whether the calibration value, calibration value, or other information in the hardware parameters have been changed manually.
Ten, test machine host power does not shine, can not move up and down.
The solution is to check whether the power supply circuit of the access test machine is connected normally; check whether the emergency stop switch is in the screwed state; check whether the power supply voltage of the access test machine is normal; check whether the insurance on the machine socket is blown, Can be installed.
11, test machine host power supply but the device can not move up and down.
The solution is to check whether it is 15S (time) after the device can not move, because the host boot needs self-test, probably need 15S time; check the upper and lower limit is appropriate location, there is a certain operating space; check the access test machine Power supply voltage is normal.
Tension testing machine maintenance
1. Regularly check the jaw parts of the screw, such as found loose, timely tightening;
The sliding surface of the steel plate in contact with the backing plate shall be kept clean and regularly coated with a thin layer of MoS2 (molybdenum disulfide) grease on the backing plate.
Regularly check the sprocket transmission, if found to be loose, please re-tension the tension wheel.
2. Maintenance of oil source
Regularly check the host and oil source where there is oil spills, such as the discovery of oil spills, should be replaced by a timely seal or combination pad;
According to the use of the machine and the use of oil, regularly replace the oil filter and filter, replace the hydraulic oil.
3. For a long time do not do the test, pay attention to turn off the host power. If the machine is in standby mode, the changeover switch should be "loaded" because if the switch is in the "rewind" position, the solenoid valve is energized and will affect the service life of the device.
4. Control system maintenance
Regularly check the controller panel connection cable is good, if loose, should be tightened in time;
After the test if there is a long time without the machine, turn off the controller and the computer;
The interface on the controller is one-to-one, and the wrong interface may cause damage to the device;
The interface on the plug-in controller must turn off the power to the controller.
5. According to the use of the machine and the use of oil, regularly replace the oil filter and filter, replace the hydraulic oil, regularly check the host and oil source where there is oil spills, if found to have oil spills, Or combination mats.
Tensile testing machine of choose and buy
1, should first consider the need to test the material tension range.
Rally range, determines the use of different sensors, it also determines the structure of the Rally, but the impact of the price is not (except door). For the general manufacturer of flexible packaging, the rally in the 100 Newton's already enough. So it is also decided to use a single arm on it. And the arm structure is the corresponding structure of the door structure, it is to adapt to a relatively large tension, such as one ton or more. So the basic need for flexible packaging manufacturers.
2, tensile testing machine test stroke
Mainly based on the nature of different materials, such as according to the needs of flexible packaging film testing performance and requirements, stroke can be 600-1500mm. Material elongation of more than 1000% can choose travel 1000 or 1200mm.
3, tensile test machine of the standard configuration.
Intelligent three basic configuration: host, microcomputer, as well as the printer, if the microcomputer function can be printed directly. Also equipped with ordinary computer. With the computer, you can carry out complex data analysis, such as data editing, local amplification, adjustable report form, the group of statistical analysis. Such as with the computer, manufacturers should be added to the corresponding control system.
4, the output results.
The results of the test results can be set arbitrarily: maximum force value, elongation, tensile strength, constant strength elongation, fixed elongation value, yield strength, elastic modulus, the maximum test force 8. It can be said that microcomputer operation when the output of the most comprehensive results.
5, can be done on the experimental project.
The industry requires a multi-purpose machine, equipped with different fixtures on the basis of doing stretching, compression, bending, tearing, cutting, 180 degree peeling, 90 degree peel test. There are some high-end rally on the market In addition to the above items, because of its high precision sensor (some reached one hundred fifty thousandth of a) can also test the friction coefficient.
6, the main product machinery configuration:
Drive, with screw drive and rack drive. The screw drive is characterized by high accuracy, high repeatability of the test; rack drive features are low, low precision, low test repeatability. Screw, the tensile accuracy measurement has a decisive role. General has a ball screw, trapezoidal screw, general screw. Among them, the ball screw the highest accuracy, but its performance depends on the computer servo system operation to play, the whole set of prices are more expensive. Using the general screw and trapezoidal screw can be achieved by the flexibility required for flexible packaging, that is 0.1-1% accuracy. Transmission, gear drive and chain drive, the former expensive, for high precision; the latter cheap, for low precision. Sensors, the main cost is life, photoelectric induction is one of the more advanced technology, generally available more than 100,000 times.
7, test speed
Some of the market equipment in the 10 ~ 500 mm / min, some in the 0.001 ~ 500 mm / min, the former generally use the ordinary speed control system, low cost, rough impact accuracy; the latter use the servo system, expensive, high precision, For the flexible packaging business, the choice of servo system, speed range 1 ~ 500mm / min is enough, so that does not affect the accuracy, the price is within a reasonable range.
8, measurement accuracy
Precision problems, including the accuracy of precision, speed accuracy, deformation accuracy, displacement accuracy. These precision values can be up to and minus 0.5. But for the general manufacturers, to achieve 1% accuracy is enough. In addition, the power of the resolution can almost reach 400,000 Rally
1) the initial correction of the main body
2) Rally testing machine precision correction
After the foot nut is poured, the feet are not fastened and the test machine is started before the cement is dry. (Cement drying time is generally not less than 10-15 days) until the cement is completely dry, fasten the nuts, the installation of the test machine to review the accuracy, whether to match the accuracy is accurate. If not meet should be re-find.
tensile testing machine in the use of the process, due to the vibration during the test prone to loose phenomenon, so the tensile testing machine for some time, the parts should be fastened.
Standard configuration: host, computer, universal fixture, professional software, communication cable
Options: standard press roller, test plate, sampling knife, floating roller fixture, non-standard fixture.
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