Customer reversed internal and external leakage of the hydraulic directional con

Stephen is from Hi-Force hydraulic equipment manufacturing company in the UK. In the second half of last year, he was promoted to the purchasing manager of Kuala Lumpur Branch due to his excellent work. Within a week of taking office, he met with complaints. A batch of their hydraulic cylinders were noisy and vibrated seriously during operation. The after-sales engineer failed to solve the problem within 3 days. The user was not satisfied. Stephen was a little worried.

Stephen browsed an article of AAK on Google: "change the design of the hydraulic directional control valve, the vibration disappeared, and AAK eliminated the Canadian factory at zero cost", and left a message: how to solve the noise and vibration of the hydraulic cylinder? After reading this message, I roughly judged that either the hydraulic directional control valve used had problems or the original design had hidden dangers. We asked Stephen to provide the hydraulic system schematic diagram and design drawings, and AAK engineer judges that the working principle of the hydraulic cylinder is reasonable, only by checking on site can we find out the source of the vibration, and then no news from Stephen. 2 weeks later, Stephen emailed that according to the last case that AAK solved the vibration of the hydraulic cylinder, they also added a triangular throttling groove to the hydraulic direction control valve, but after installation, the hydraulic cylinder still vibrated. Their engineers said that AAK solution was a lie. I was speechless and didn't want to explain anything, so I ignored him.

3 days later, Stephen emailed us again, and sent a video of the hydraulic cylinder working and asked our help to check. AAK engineers found that the hydraulic cylinder will emit rhythmic noise and vibration whenever the load drops in the actual work, and preliminarily judged that there is a problem with the hydraulic direction control valve. AAK technical team discussed again according to the drawings, the working principle diagram of the hydraulic cylinder and the working video of the hydraulic cylinder, and confirmed that the problem lies in the hydraulic direction control valve. I told him that AAK could redesign the hydraulic directional control valve and asked him to send us samples of the original hydraulic directional control valve. Stephen may have no choice but promised.

5 days later, we received the sample of the original hydraulic directional control valve, which confirmed the judgment of our engineers that the internal leakage and external leakage of the original hydraulic directional control valve was reversed. 1 week later, AAK sent the newly designed external leakage type hydraulic directional control valve. Stephen informed by email that the noise and vibration problems of the hydraulic cylinder had been solved after using AAK external leakage hydraulic directional control valve. In the past 4 weeks, their engineers, from suspicion, disdain to admiration, wanted to know how AAK engineers found and solved problems, and sent out new hydraulic directional control valves in only 1 week.