The quality of the valve spool can only be measured and compared from the 4 main aspects: the movement sensitivity, stability, no leakage and long service life of the spool in the valve body. The 6 processing procedures and 6 parameters of AAK valve spool also impressed Russian customers.
 
At present, some of the valve spools used by the hydraulic valve manufacturers are purchased outside from the valve spool factory, which is the common market goods well known in the hydraulic valve industry, with high output and low price. There are also hydraulic valve manufacturers that produce valve spools themselves, but the workshop only produces and tests according to the process sheet of the production department, and basically does not consider the type of hydraulic valve, hydraulic force on the valve spool, flow coefficient of the valve spool, pressure and flow characteristics, service scenarios of the hydraulic valve, and media. That is to use the same production standard to produce all different types of valve spools.
 
Boris from Russia is mainly responsible for purchasing high-end hydraulic valves, and some requirements are jokingly called curiosity by peers. Due to restriction of production process or lack of awareness of quality control, many hydraulic valve manufacturers dare not accept his orders. Just last month, our old customer, Erin, brought Boris to our company. I was surprised at the moment we met. Maybe he was really worried and went straight to the subject, there was an order for hydraulic flow valve that couldn't pass the inspection, and then took out 5 samples of hydraulic flow valve.
 
We conducted simulation tests according to the service scenarios, media and parameter requirements of the flow valve provided by him. The test results of the flow valve are not optimistic, the valve spool is stuck, slightly leak and unstable. Boris spread his hands, what's the solution? I joked and asked him why you came to us all of a sudden. He pointed to Erin. She told me that if multiple factories failed to make qualified samples continuously, you could only try AAK Hydraulic Valve. I told him directly that Erin was right and you were right to come here. The valve spools of these flow valves are not accurate enough. Give me 10 days and we will give you 5 high-precision flow valves.
 
10 days later, his Shanghai Office received 5 samples of our high-precision flow valves. 2 days later, Boris asked us how long it would take to produce 10,000 flow valves. It seems that the sample quality of AAK flow valve has convinced him.
 
Why can AAK Hydraulic Valve produce the flow valve that the peers can't or don't want to produce? AAK Hydraulic Valve not only has 6 processes, but also 6 parameter indexes as quality assurance:
 
1. Rough machining of valve spool, select appropriate bar material, cut the size, normalize and quench and temper. Parameter requirements: hardness above 32HRC.
 
2. Finish machining for the first time, flat end face, drill the center hole, the core is in the hole row, and the hole accuracy. Parameter requirements: the accuracy shall not be higher than 0.005mm, and the surface roughness Ra value shall not be higher than 0.16 μ m.
 
3. Step 3: the semi-finished work piece is subject to vacuum quenching unique to AAK and then stabilized. It is required to be cold treated at - 80 ℃ for 2h, aging temperature of 420 ℃ and heat preservation of more than 10h. Parameter requirements: hardness above 66HRC.
 
4. Finish machining again. First rough grind the outer circle and each end face of the shoulder. The core is the size matching between the outer circle and shoulder of the valve spool and the valve sleeve. Different clearance dimensions are implemented according to different hydraulic valves. Parameter requirements: no more than 0.005--0.035mm
 
5. Grind the outer circle carefully, after stabilizing the work piece, then grind the center hole of valve spool. Parameter: surface roughness Ra value is not higher than 0.1 μ m.
 
6. Finishing. For the high precision hydraulic valve, we adopt mirror grinding and finishing, double wheel honing, and our peers basically adopts fine grinding. Parameter requirements: surface roughness Ra value is not higher than 0.01 μ m.
 
After all valve spool processes are completed, our valve spool Ra value is 0.01 μ m. Ra value of valve spool of most peers is 0.08 μ m. Ra value of valve spool of a few peers is 0.02 μ m. The comparison of these values is the embodiment of our valve spool process strength.
 
AAK Hydraulic Valve spool has 6 processes and 6 parameters, which has taken 6 steps ahead of its peers. AAK Hydraulic Valve precision parameters, peers may be able to think of, but in most cases cannot achieve it, you are encouraged to have a small try with AAK Hydraulic Valve.