Malcolm is a purchaser from an American hydraulic equipment manufacturer. He has purchased various hydraulic valves from AAK for some years. We know each other very well. At the beginning of the year before last, their company received an urgent order from a customer in South America. The company required that the accessories of the whole hydraulic system must be in place within 20 days. AAK is their long-term supplier of hydraulic valve blocks. Malcolm estimates that if the hydraulic valve blocks are purchased from AAK this time, including the transportation and customs clearance time, it will be over 20 days. AAK is only required to offer the quotation according to the hydraulic valve block drawings for their file and is informed that due to time constraints, they will first purchase the hydraulic valve blocks from the local hydraulic valve manufacturer this time. About 8 months after our quotation, Malcolm asked by email about what is the reason for the leakage of the hydraulic valve blocks. I asked jokingly if leakage happened in the hydraulic valve blocks purchased locally last time. He said that the customer initially complained that about 30% of the hydraulic valve blocks were leaking. The local manufacturer also replaced the bad hydraulic valve blocks with new ones. However, 3-4 months after installation, the customer reported that there was leakage fault of the hydraulic valve blocks again. Now the customer is not satisfied with the stability of the hydraulic valve blocks and needs the leakage problem of the hydraulic valve blocks solved at one time. The trouble is that the local hydraulic valve manufacturer in the United States does not cooperate to replace the hydraulic valve blocks again. We replied that if we simply look at the leakage cause of the hydraulic valve block, the probability is that the surface roughness of the hydraulic valve block is not up to standard, or the roughness Ra value of the hydraulic valve block is unstable. According to the requirements of these working conditions of your hydraulic equipment, if the Ra value is stable at 0.4um, the problem of hydraulic valve block leakage will not occur. 10 days later, AAK sent 12 samples of hydraulic valve blocks for emergency first. After 20 days, the remaining 30% of the hydraulic valve block was sent from AAK. Now, 12 months have passed, and no complaint from customer. Malcolm mentioned 2 days ago that the customer was ready to place an order again. This time, his owner said that no matter how urgent it was, it was necessary to purchase from AAK, because AAK hydraulic valve block was the most trustworthy, and the owner would communicate with the customer about the delivery date. Why can AAK achieve the surface roughness Ra value of hydraulic valve block to 0.4um? First of all, the Ra value of the hydraulic valve is the cornerstone. The coarser the surface, the easier it is to wear. The intermediate gap gradually increases during use
