subject: Analysis: How to choose a universal testing machine - testing machine - Education Industry [print this page] Analysis: How to choose a universal testing machine - testing machine - Education Industry
Different test UTM testing machine including one or more vertical load of the column, the column is installed on a fixed base level, at the top level there is a mobile crosshead (cross beams). Now the UTM test machine, the column usually have ball screws to fix the movable crosshead. UTM with the framework of the maximum size of load levels and measurement of load / Tension dynamometer to the common characterization. Dynamometer attached to rely on electric motors, or hydraulic device driven movable cross head. Series with clamp force dynamometer measuring the size, or by digital display PC Machine displays the results. Many UTM dynamometer with interchangeable, so you can test different materials with the match. Static test using a standard Electronic Universal testing machine to carry out, often loading speed range of 0.001 ~ 20in./min1in .= 2.54cm. Dynamic test or tests, such as crack growth and cyclic fatigue tests are usually hydraulic servo system using UTM testing machine to carry out, longer, load lower.
Early testing machine UTM has a similar electronic components and Recorder . Has now been replaced by numerical control equipment and PC software. The new automation equipment can run tests, but also display data, and sometimes even run side edge record. Previous recorder, including PC software, the figures before the age of the user received the test message is load / deformation curve, Y-axis stress, X-axis deformation. These curves also need to be calculated and explained. The latest system is still able to provide these curves, but while computing the data, such as yield strength, tensile strength and modulus data.
Currently using universal testing machine for testing the most common item is the tensile strength and tensile modulus, bending strength and modulus. In accordance with ASTMD638 and ISO527 tensile test, the spline both ends of the clamping fixture, a fixture is stationary and the other fixed cross head, departure from the fixed clamp movement, traction until spline spline break, fracture when the crosshead will stop automatically. Bending test ASTMD790, D6272, and ISO178, spline is fixed on the test machine Machine tool Bearing on the two. This experiment, the direction of crosshead movement and move in the opposite direction tensile test, there is no support to the center of a push instead of pulling spline, spline bending or even breaking up. Because most thermoplastic Plastic Material will not fracture in this test, it is impossible to break bending strength. Thus, the standard test method requires calculating strain of 5% of the bending stress. Compression test is rarely applied
UTM test machine, although this is ASTMD1621 and ISO844 standards in terms of rigid plastic foam is a major test. UTM test machine can also be used for any shape of plastic products such as bottle crush test, to a certain height or to deformation of the sample and break the stress that is required for compression strength values.
UTM vendors, according to statistics, for plastic materials, the shear test is more rare. Shear strength value is placed in the sample punch-type shear device in the measured. Impact velocity is 0.005in./min, until the movable part of the sample completely exposed to the fixed part. Shear strength value of the stress / shear area value. This thin film and sheet products is important because this type of damage easy to occur in this category, but this is not the other extrusion and injection molding products designed with the largest factor. In accordance with ASTMD732 (no equivalent ISO standard) standard test, the sample is commonly used plastic sheet or 0.005 ~ 0.500in. Thick plastic discs.
Electronic mechanical testing machine UTM
Common electronic UTM Testing Machine capacity 100 ~ 135000lb. Size larger, the higher the cost. In general, the vertical device smaller and more easy to operate, and also the help of samples of its own gravity, so difficult samples such as films can heavier plastic parts with the same easy to control. Single Column Testing Machine UTM lower power range, low prices, structural capacity is generally 1000lb. Gate-type structure of UTM testing machine capacity up to 1000 ~ 135000lb. Dynamometer also most suitable for a testing machine UTM force structure and the sample value classification. For example, a 100lb to 1000lb dynamometer installed in the mold box, providing 100lb of test load. Dynamometer should not exceed the capacity of the sample predicted fracture load too much, otherwise it may affect the accuracy of test results.
