With the progress of society and the enhancement of national strength, all kinds of new materials emerge in endlessly, the performance of the original materials has been further improved, and the use of the surface is also expanding, so the inspection of materials also put forward higher requirements. As we all know, before the 1980s, the use of material testing machine was limited to a few fields such as metal. Now, the use of material testing machine is no longer limited to metal and other fields, it has been extended to all industries. Material testing machine from the past manual hydraulic testing machine dominates the world, today, a variety of control modes coexist, different performance characteristics, blooming era. In this dazzling array of testing machines, how to choose a suitable testing machine for their own characteristics is the concern of most users. At present, most of the material tests are static performance tests, so Xiaobian makes a simple comparative analysis of the performance characteristics of the common universal testing machines in the market.

1、 Types of common universal material testing machines

At present, there are mainly two series of universal material testing machines in the market

1. Hydraulic series: manual hydraulic universal material testing machine, electro hydraulic servo hydraulic universal material testing machine

2. Electronic universal series: conventional electronic universal material testing machine, high performance electronic universal material testing machine

Their performance is different, advantages and disadvantages coexist, each has its own user groups.

2、 Performance characteristics

1. Hydraulic series

1) Manual hydraulic universal material testing machine

Manual hydraulic universal material testing machine mainly uses simple high-pressure oil source as power source, manual adjustment valve as control element, and manual loading, so it belongs to open-loop control system. Due to the limitation of oil flow and the structure of the main engine, the piston stroke of the oil cylinder is small, and the common stroke is about 300 mm, and the test speed is generally small. Zhejiang vitiligo hospital is affected by the price factor, the force sensor generally uses the pressure sensor (the large tonnage basically uses the pressure sensor). As a result, the accuracy is low and the range is small. Generally, the accuracy is level 1 or level 2, and the range is 4% - 100% F.S. Influenced by the friction of oil cylinder, the tonnage is difficult to be very small, and the domestic minimum is 5T. However, due to its unique characteristics of low price and large tonnage, it is still widely used in finished product inspection and single material index test.

2) Electro hydraulic servo universal material testing machine

It mainly uses precision high-pressure oil source as power source, and uses servo valve or proportional valve as control element for closed-loop automatic control, so it has high control performance. Generally, it can realize three control modes of load, strain and displacement. Like the manual hydraulic universal material testing machine, its testing speed is low due to the limitation of oil flow. Because of the closed-loop automatic control, the system stiffness becomes the key to the normal operation of the whole system. As we all know, the stiffness of the liquid is relatively low. In order to reduce the impact of the liquid on the stiffness of the whole machine as far as possible, the stroke of the general electro-hydraulic servo testing machine is not big. Also affected by the stiffness of the whole machine, the tonnage of the electro-hydraulic servo testing machine can not be very small, basically more than one ton. But because it has many control modes, it has the characteristics of flexible use and high performance.

2、 Electronic universal series

1) Conventional electronic universal material testing machine

Conventional electronic universal testing machine mainly uses servo motor as power source, lead screw and screw nut as executive parts to realize the speed control of moving beam of testing machine. Its test speed range can be adjusted. Take rgm-200 as an example, its test speed can reach 0.001mm/min-1000mm/min, the speed ratio can reach 1 million times, and the test stroke can be determined according to the needs, up to several meters. This is the kind of hydraulic testing machine in any case can not achieve. With the development of electronic technology and the improvement of the performance of servo motor, the motor used by electronic universal has made a qualitative leap from the early DC servo motor to the current AC servo motor, from the early use of silicon controlled rectifier for phase-shift trigger control to today's use of a variety of power modules for pulse width modulation control, In people's mind, the high failure rate and poor performance of electronic universal no longer exist. Because the conventional electronic universal testing machine adopts speed control, the requirement of system stiffness is not high, which creates favorable conditions for the realization of small tonnage testing machine. From the current international and domestic situation, testing machines under one ton are basically conventional electronic universal testing machines. It is the most widely used and cost-effective.

2) High performance electronic universal testing machine

High performance electronic universal testing machine is the same as the conventional electronic universal testing machine, it also uses servo motor as the power source, screw, screw as the executive parts, it is different from the conventional electronic universal testing machine is that its control mode can be load control, also can be strain control or displacement control. In addition to the wide speed and large stroke of conventional electronic universal testing machine, it also has all the advantages of electro-hydraulic servo testing machine, so it is the best universal material testing machine at present.