A while ago, there was an international parcel from Brazil on my desk. I thought it was from an old Brazilian client, Machado, who sends AAK hydraulic cartridge valves that need to be developed every month. That day, I was a bit busy and forgot to unpack the package. It wasn't until the next day that I received an email from Brazil that I learned it was a hydraulic cartridge pressure control valve sample sent by a new customer, Faba, as well as a specially designed valve spool.
Faba mentioned in the email that he found hydraulic cartridge valve manufacturer AAK in China on Google and asked if AAK could customize the special valve spool of this hydraulic cartridge pressure control valve. After communication, we learned that he encountered a problem with the valve spool accuracy not meeting the standard when purchasing this hydraulic cartridge pressure control valve from the original manufacturer. Due to its unique shape and accuracy of within 2μm, the original manufacturer failed 3 times.
I was curious why it is necessary to have a specially designed valve spool to match this hydraulic cartridge pressure control valve. Faba did not discuss it much, perhaps there are trade secrets or patents. He only asked, can AAK try a sample? Although we were not 100% certain, Faba's contempt has ignited our engineer's desire for challenge.
We first thought about the materials and chose alloy steel with the same hardness but easy to machine. On the premise of ensuring the overall size of the valve spool, a rotary material reduction processing method is adopted to lay a solid foundation for the next step of grinding. The key lies in the presence of Japan's Mitutoyo contour measuring instrument to constantly check whether the accuracy under special shapes meets the standards After 50 days, 6 hydraulic cartridge pressure control valve samples were sent out.
6 weeks later, Faba informed us via email that although AAK changed the spool material of the hydraulic cartridge pressure control valve, the accuracy was within 2μm. The valves have been working for 4 weeks and no leakage was found yet. As long as the service life of the hydraulic cartridge pressure control valve reaches 12 months, they can fully promote their equipment. Meanwhile, Faba emphasized that the spool of this hydraulic cartridge pressure control valve cannot be revealed to any third party.
For this hydraulic cartridge pressure control valve, I would like to summarize the AAK inspection and the customized fixture combined with the special shape of the valve spool to ensure that there is no deviation in the rotation of the valve spool. After installing the valve spool into a customized fixture, set a speed of 50mm/s, start the measuring instrument, and the built-in contact needle starts 360 degrees, and detects the surface geometry of the valve spool through multiple cycles. Due to the special shape of the valve spool, changes in its geometric shape cause displacement of the contact needle. The generated analog signal of the surface contour ratio is automatically converted into a digital signal, which is then collected and integrated into the program for automatic comparison. The core of testing is not only the customization of fixtures, but also the setting of rotational speed, which needs to be explored based on the surface geometry of the valve spool. The hard power of AAK is reflected in these soft actions. Most hydraulic cartridge pressure control valve manufacturers mechanically refer to the user manual of the measuring instrument during the testing process.
AAK hydraulic cartridge pressure control valve, hard power, soft action, you can also give it a try!
AAK HYDRAULIC CARTRIDGE VALVES (666) 2023-09-07