In the technical parameters of testing machine precision grades classification, we often see the accuracy of 0.5 or 1 and other parameters. What do these levels represent? Tensile testing machine 0.5 or 1 is to classify the accuracy level of the instrument. In ISO7500-1 Static Uniaxial Testing Machine Inspection Part 1_ Tensile and (or) Compression Testing Machines, the tensile testing machine is divided into 0.5 Grade 1, Grade 1, Grade 2 and Grade 3, among which grade 0.5 represents the highest grade, and the accuracy decreases in turn. In addition, if we send the instrument to a third-party measurement agency, they will verify the instrument in one fell swoop with the verification procedure JJG 139-2014 Tension, Pressure and Universal Testing Machine Verification Procedure, and give the accuracy level.
In this standard, the testing machine is divided into 3 levels. Different levels correspond to the measured force error range, zero point drift, displacement error, noise, coaxiality, etc. There are clear regulations, and all the corresponding technical parameters of level 0.5 can be determined. The testing machine is 0.5 grade accuracy. In other words, a tensile testing machine is rated as 0.5 or 1 is reflected by multiple indicators, not to say that the force measurement unit (sensor) of the testing instrument is only used, and the accuracy level can be determined when the error range is reached. The specific parameters are as follows:
| Test machine level | Level 0.5 | Level 1 | Level 2 |
| Zero drift z% | ±0.5 | ±1 | ±2 |
| Displacement indication error qD% | ±0.5 | ±1 | ±2 |
| Noise | ≤75dB | ≤75dB | ≤75dB |
| Maximum allowable coaxiality % | 15 | 20 | 25 |
| Standard dynamometer accuracy | 0.1级 | 0.3级 | 0.3级 |
For users, they should first understand the classification of the testing machine before choosing a tensile testing machine. Some manufacturers often do not clearly mark the specific testing machine level in order to confuse customers. Instead, they use a method with a resolution of tens of thousands of times the range. It seems that the accuracy is Very high, but it is not. Some manufacturers do not have a measuring instrument production license (CMC), but they arbitrarily claim that the precision of the tensile machine is 0.5 grade or 1 precision tensile machine, which is not standardized. Remind users to make a distinction and confirmation, otherwise buying products that do not meet the requirements will bring unnecessary trouble to their quality control work
