In this year, , an customer, visited 5 hydraulic valve factories before and after, and made samples of hydraulic relief valve with 1m inner hole for 3 times, but none of them reached the accuracy requirements. sent samples and met the standard for the 1st time, finally chose to cooperate with . The inner hole accuracy is not enough, which is mainly caused by the different built in equipment of honing machines equipped by many hydraulic valve manufacturers. Conventional honing machines use diamond reamers., Because the main cutting part of the diamond reamer is at the tool head, the tool head wears quickly. After the head is worn, it is very easy to cause the size of the hole bottom to be small, resulting in the poor cylindricity of the whole hole and affecting the accuracy. This is the key to the 5% accuracy error. Many hydraulic valve manufacturers are not aware of this key point. , a purchaser from a hydraulic valve in , has an inquiry for a special hydraulic relief valve, and the inner hole accuracy must be controlled within 1m. checked with the original hydraulic valve supplier, and got reply that only the hydraulic valve manufacturer equipped with high precision honing machine is able to make the hydraulic relief valve with 1m inner hole accuracy. According to the equipment configuration, has contacted with more than 10 hydraulic valve manufacturers, determined to visit 5 hydraulic valve manufacturers, and asked 3 powerful factories to sample the hydraulic relief valve. After testing and comparing the samples received from these 3 hydraulic valve factories, all failed to meet the standard. asked the manufacturer with the highest accuracy to continue to improve the proofing, and there is still 0.1m gap. The factory gave up and introduced HYDRAULIC VALVE to him, maybe can do the hydraulic relief valve with 0.1m inner hole accuracy. According to his hydraulic relief valve drawing, we advised that we can send 1pc hydraulic relief valve quality sample after 10 days. 5 days after successfully sent the hydraulic relief valve sample, Bowen informed that the accuracy met the standard. He wanted to know why so many hydraulic valve manufacturers could not achieve 1m inner hole hydraulic relief valve, even if the hydraulic valve manufacturers promised to do so and they also have high precision honing machines, but several proofing did not meet the standard. How did hydraulic valve achieve it Honing machine is really helpful for the machining of high precision inner hole. Due to different equipment configuration, not every hydraulic valve manufacturer can produce the hydraulic relief valve with 1m inner hole accuracy.