液压式万能材料试验机是力学计量检定中经常遇到的仪器 ,ＪＪＧ１３９ -１９９９检定规程中要求其示值允许误差通常不超过±１% ,计量部门对其进行计量检定时 ,其示值误差主要通过以下几种方式体现 :一、示值正偏差超差。二、示值负偏差超差。三、示值误差在度盘上呈现“前正后 Hydraulic universal testing machine mechanical metrology is often encountered in the test equipment, test procedures JJG139 -1999 requirements show its allowable error is usually not more than ± 1%, the metrological department of the metrological verification, the indication error of the main Through the following ways: First, the positive deviation is poor tolerance. Second, showing negative deviation tolerance. Third, showing the error on the dial showed "after the front