发布时间：2020.06.11 分类：新闻中心 来源： 点击：0次
【Tensile testing machine】Teach you how to choose tensile testing machine
1. Tensile properties of high molecular polymers...
拉伸测试（应力-应变测试）通常将材料样品的两端以一定距离夹在两个固定装置上。 这两个夹具分开并以一定速度拉伸样品，以测量样品上的应力变化。 直到样品被破坏。
According to the different load measurement methods, the tensile testing machine can be roughly divided into two types of pendulum tensile testing machine and electronic tensile testing machine. At present, the electronic tensile testing machine is mostly used.
3. Electronic tensile testing machine
Since the flexible packaging material is mainly a polymer or its related materials, as mentioned above, the elongation of the polymer material is much better than that of metals, fibers, wood, plates, etc., so the tensile machine for detecting polymer There is a certain difference from the conventional tensile testing machine for tensile properties of materials. In particular, it is necessary to pay attention to the effective stroke of the electronic tensile machine and the sample fixture.
In the tensile test, although the size of the sample used is small, the elongation of the material is generally relatively high, so the tensile performance of the flexible packaging material needs to be equipped with a tensile machine with a large stroke, otherwise the fixture operation may exceed The service limit of the stroke causes damage to the equipment.
The calculation formula for the elongation at break or yield elongation (εt, unit is %) given in GB13022-91 "Test Methods for Tensile Properties of Plastic Films" is as follows: where: εt is the elongation at break or yield extension Elongation; L is the distance between the marking lines when the specimen breaks or yields; L0 is the distance between the marking lines.
It should be noted that in the calculation of elongation, we only collect the elongation between the two markings on the sample.
The marking lines are drawn on the finished sample by printing or manually (the addition of the marking line should have no effect on the sample), and what is the distance between the marking lines? Most of the distances given by different standards are different, and in the same standard, different sample sizes are often given for different materials, so the distance between the marking lines is also different, but this is conducive to the detection of extension Very long or very small material and get the best test results.
在标准中，与标记线之间的距离相对应的夹具之间的初始距离在80至115 mm之内。 如果两个夹具之间的样品可以保持相同的伸长率并假定为500％，则拉伸机的有效行程需要为480690mm，如果样品的伸长率为1000％，则拉伸机的有效行程为 至少应确保880mm以确保正常测试。
"Due to the particularity of the mechanical properties of polymer materials and the special use of flexible packaging materials, the thickness of the samples tested by the flexible packaging materials is very thin, and the general fixtures cannot meet the requirements. Improper use will cause the specimens to break at the fixture and cause the test to fail. .
TF-213 intelligent electronic tensile testing machine.
Shanghai Instrument is an enterprise specializing in the production of flexible packaging materials testing equipment. Especially for the characteristics of large elongation of flexible packaging materials, the TF-213 intelligent electronic tensile testing machine has been made with a stroke of up to 1000mm, which can be stretched, peeled, torn, and heated. Sealing and other seven kinds of tests, and professionally designed various types of test fixtures dedicated to flexible packaging materials. It is a mechanical property tensile testing machine tailored for flexible packaging materials.