How to ensure the accuracy of the thermal fuse tensile test results

How to ensure the accuracy of the thermal fuse tensile test results
Introduction
As a material widely used in many fields, the performance of thermal fuse directly affects the quality and use effect of the product. The tensile test is one of the key means to evaluate the performance of thermal fuse. Through the tensile test, the tensile strength, elongation at break and other important mechanical performance indicators of the thermal fuse can be obtained, which is of great significance for ensuring product quality, guiding production and research and development. So, how to ensure the accuracy of the thermal fuse tensile test results? This article will discuss in depth from multiple aspects.

1. Selection and calibration of test equipment
Choose a suitable tensile testing machine: The tensile testing machine is the core equipment for the thermal fuse tensile test, and its accuracy and performance directly affect the accuracy of the test results. The test machine with a suitable range should be selected according to the expected tensile force range of the thermal fuse to ensure the measurement accuracy during the test. For example, for thermal fuses with small tensile force, an electronic universal testing machine can be selected, which has high control accuracy and measurement accuracy and is suitable for small load and high precision tests.
Calibrate equipment regularly: Even if a high-quality testing machine is selected, if it is not calibrated regularly, it will lead to deviations in the measurement results. Therefore, the testing machine must be calibrated regularly in accordance with the equipment manufacturer’s recommendations and relevant standards to ensure that its measurement accuracy is within the allowable error range. At the same time, the fixture, extensometer and other auxiliary equipment must be calibrated and checked to ensure the accuracy of the entire test system.

2. Preparation and processing of specimens
Standardization of specimen size and shape: The size and shape of the specimen must be prepared strictly in accordance with relevant standards, such as ASTM D638 “Plastic Tensile Test Standard” and ISO 527 “Plastic Tensile Performance Standard”. The common shape of hot melt tensile specimens is dumbbell-shaped, and its dimensions should meet the standard requirements, including length, width, thickness, etc. Only by preparing specimens that meet the standards can the comparability and accuracy of the test results be guaranteed.
Cleaning and processing of the specimen surface: During the preparation of the specimen, ensure that the specimen surface is clean and free of dirt, scratches and other defects. Dirt or defects on the specimen surface may introduce errors during the test and affect the accuracy of the test results. The specimen surface can be cleaned with an appropriate solvent or detergent, and be careful not to damage the specimen surface.
Conditioning of the specimen: The performance of the thermal fuse may be affected by factors such as ambient temperature and humidity, so the specimen needs to be conditioned before testing. Place the specimen in a specific environment, such as a constant temperature and humidity chamber, so that it reaches a balanced state under the specified temperature and humidity conditions to reduce the impact of environmental factors on the test results.

3. Control of the test environment
Temperature control: Temperature has a significant effect on the tensile properties of the thermal fuse. Generally speaking, an increase in temperature will lead to a decrease in the tensile strength of the thermal fuse and an increase in the elongation at break. Therefore, when conducting a tensile test, the temperature of the test environment must be strictly controlled to meet the relevant standards or test requirements. A temperature control system, such as an environmental test chamber, can be used to control the temperature fluctuation of the test environment within the allowable range.
Humidity control: Humidity will also affect the performance of the thermal fuse, especially for some thermal fuse materials with strong hygroscopicity. In a high humidity environment, the thermal fuse may absorb moisture, thereby changing its mechanical properties. Therefore, it is also necessary to control the humidity of the test environment to avoid the impact of humidity changes on the test results.

4. Operational specifications during the test
Correctly install the specimen: When installing the specimen on the fixture of the test machine, ensure that the specimen is installed correctly and clamped firmly. The position of the specimen in the fixture should be correct, avoiding eccentric clamping or loose clamping, otherwise it will cause uneven force on the specimen during the test and affect the accuracy of the test results. At the same time, pay attention to the selection and use of the fixture to ensure that the surface of the fixture is smooth and burr-free to avoid damaging the specimen.
Set a suitable stretching speed: The stretching speed is one of the important factors affecting the test results of the hot melt wire stretching. Different stretching speeds may lead to different stress-strain curves and test results. Therefore, it is necessary to set a suitable stretching speed according to relevant standards or test requirements. For example, when testing the tensile strength and elongation at break of hot melt adhesive, a stretching speed of 5mm/min is usually used.
Avoid external interference: During the test, try to avoid external interference, such as vibration, airflow, etc. External interference may cause measurement errors of the test machine or the specimen is subjected to additional stress during the test, thereby affecting the accuracy of the test results. Therefore, the test environment should be kept quiet and stable to avoid interference from external factors.

5. Data processing and analysis
Accurately record data: During the test, carefully observe the display data of the testing machine, and accurately record the load and displacement of the sample during the stretching process. At the same time, the fracture phenomenon and fracture position of the sample should also be recorded. This information is of great significance for analyzing the test results and evaluating the performance of the thermal fuse.
Reasonable data processing method: Use reasonable data processing methods to analyze and process the test data to obtain accurate test results. For example, by drawing the stress-strain curve, you can intuitively understand the mechanical behavior of the thermal fuse during the stretching process; calculate the tensile strength, elongation at break and other performance indicators of the thermal fuse according to the test data, and perform statistical analysis on the test results of multiple samples to evaluate the reliability and repeatability of the test results.
Uncertainty analysis of results: Perform uncertainty analysis on the test results, evaluate the degree of influence of various factors on the results during the test process, and determine the confidence interval of the test results. This can not only help us understand the accuracy of the test results, but also provide a basis for the improvement and optimization of the test methods.

6. Personnel quality and training
Professional training: The professional quality of the operator has an important impact on the accuracy of the hot melt wire tensile test results. Therefore, the operator should be professionally trained to familiarize himself with the operating methods, test procedures and standard requirements of the test equipment, master the correct specimen preparation and installation skills, and the methods of data processing and analysis.
Continuous learning and experience accumulation: The field of hot melt wire tensile testing is constantly developing and updating, and new testing technologies and methods are constantly emerging. Operators should continue to learn and pay attention to industry trends, participate in relevant training courses and academic exchange activities, and continuously accumulate experience to improve their professional level and testing capabilities.

7. Selection of test standards and methods
Follow authoritative standards: When conducting hot melt wire tensile tests, it is preferred to follow authoritative test standards, such as international standards or national standards such as ASTM and ISO. These standards have been extensively studied and verified in practice, are scientific and reliable, and can ensure the accuracy and comparability of test results. For example, when testing the tensile properties of hot melt adhesives, you can refer to ASTM D638 or ISO 527 standards.
Choose the appropriate test method: Choose the appropriate test method according to the characteristics of the thermal fuse and the purpose of the test. Different test methods may have different effects on the test results. For example, for some special types of thermal fuses, special fixtures or test devices may be required to ensure the accuracy of the test results.

8. Comparison and verification
Regular comparative tests: In order to ensure the accuracy of the test results, comparative tests can be performed regularly with other authoritative testing agencies or laboratories. By comparing the test results, problems in the test process can be found, and the test methods and operating procedures can be adjusted and improved in time to improve the accuracy of the test results.
Verification using standard specimens: Verification tests are performed using standard specimens with known performance, and the test results are compared with the standard values ​​of the standard specimens to evaluate the accuracy of the test equipment and test methods. If there is a large deviation between the test results and the standard values, the test equipment needs to be calibrated or the test methods need to be improved.

9. Actual case analysis
Case background: A thermal fuse manufacturer found during the production process that there were large differences in the results of different batches of thermal fuses in the tensile test, resulting in unstable product quality, affecting the customer’s experience and the company’s reputation.
Problem analysis: Through a comprehensive inspection of the test process, the following problems were found: the test equipment was not calibrated regularly, resulting in a decrease in measurement accuracy; the size deviation was large during the sample preparation process, and there was dirt on the sample surface; the temperature and humidity of the test environment were not effectively controlled; the operator did not strictly follow the standard operation, and the stretching speed was inconsistent.
Improvement measures: In response to the problems found, the company has taken a series of improvement measures: fully calibrate and maintain the test equipment; strengthen the quality control of the sample preparation process to ensure that the sample size and surface quality meet the standard requirements; install a temperature and humidity control system to stabilize the temperature and humidity of the test environment within the specified range; provide professional training for operators to improve their operating level and quality awareness.
Improvement effect: After a period of improvement, the stability and accuracy of the hot melt wire stretching test results have been significantly improved, the quality differences between different batches of products have been significantly reduced, customer satisfaction has been greatly improved, and the company’s market competitiveness has also been enhanced.

Conclusion
Ensuring the accuracy of the thermal fuse tensile test results is a systematic project, which requires strict control of every link from the selection and calibration of test equipment, preparation and processing of specimens, control of the test environment, operating specifications during the test, data processing and analysis, personnel quality and training, selection of test standards and methods, comparison and verification, etc. Only in this way can accurate and reliable test results be obtained, providing strong guarantees for the production, research and development, and quality control of thermal fuses. In actual operation, we should constantly sum up experience, continuously improve test methods and processes, and improve the level of test technology to meet the market’s strict requirements for the quality of thermal fuse products.