Selection and purchase of tensile testing machine

1. The tensile range of materials to be tested should be considered first
The different range of pulling force determines the different sensors used, and also determines the structure of the pulling machine, but this item has little impact on the price (except the door type). For general flexible packaging manufacturers, the tension range of 100 newtons is sufficient. Therefore, it is decided to use the single-arm type. The structure corresponding to the single-arm structure is the portal structure, which is suitable for relatively large pulling force, such as one ton or more. So it is basically unnecessary for flexible packaging manufacturers.
2. Problems with test travel
According to the performance and requirements of the flexible packaging film to be tested, the stroke is 600-1500mm. If the material elongation exceeds 1000%, the stroke can be 1000 or 1200 mm.
3. Standard configuration problem
There are three basic configurations of intelligence: mainframe, microcomputer, and printer. If the microcomputer is powerful, it can print directly. It can also be equipped with ordinary computers. With computers, complex data analysis can be carried out, such as data editing, local amplification, adjustable report form, and statistical analysis in group style. If computer is used, the manufacturer shall add corresponding control system.
4. Output results
The output results of test results can be set arbitrarily: maximum force value, elongation, tensile strength, constant force elongation, constant elongation force value, yield strength, elastic modulus, and maximum test force. This can be said to be the most comprehensive result of microcomputer operation. The products of some foreign manufacturers can generally export these 8 items. Some domestic manufacturers can output 5-6 items, while others can only output the maximum force value, average value and minimum value.
5. On the experimental items that can be done
Flexible packaging requires a tensile machine with multiple functions, that is, on the basis of different fixtures, tensile, compression, bending, tearing, shearing, 180-degree peel and 90-degree peel tests can be performed. In addition to the above items, some high-end tensile machines on the market can also test the friction coefficient because of their high sensor accuracy (some reach one in 350000).
6. Main configuration of product machinery
Drive, including lead screw drive and rack drive, the former is expensive, used for high precision and high test repeatability; The latter is cheap, used for low precision and low test repeatability. The lead screw plays a decisive role in the measurement of tension accuracy. Generally, there are ball screw, trapezoidal screw and general screw. Among them, the ball screw has the highest accuracy, but its performance depends on the operation of the computer servo system, and the price of the whole set is also relatively expensive. The precision required by the flexible packaging can be achieved by using the general lead screw and trapezoidal lead screw, that is, 0.1-1% precision. Transmission includes gear transmission and chain transmission. The former is expensive and used for high precision; The latter is cheap and used for low accuracy. The main cost of the sensor is its service life. Photoelectric induction is a relatively advanced technology, which can be used more than 100000 times.
7. Test speed
Some of the equipment on the market are 10~500mm/min, and some are 0.001~500mm/min. The former generally uses ordinary speed control system, which is low in cost and rough affects the accuracy; The latter uses servo system, which is expensive and high in accuracy. For flexible packaging enterprises, it is sufficient to select servo system with speed range of 1~500mm/min, which will not affect the accuracy and the price is within a reasonable range.
8. Measurement accuracy
Accuracy problems include force measurement accuracy, velocity accuracy, deformation accuracy and displacement accuracy. These precision values can reach up to plus or minus 0.5. However, for general manufacturers, 1% accuracy is sufficient.