George comes from a hydraulic valve company in Germany. He likes to choose old suppliers to place orders. Some time ago, he placed an order of hydraulic pressure control valve with machining allowance of 0.3mm with an old supplier. After 3 proofing, his customer still did not approve the samples of the hydraulic pressure control valve. George was very angry. Before ordering this hydraulic pressure control valve, he confirmed the parameters with the manufacturer several times, especially the machining allowance of 0.3mm. The manufacturer guaranteed no problem. Unexpectedly, the accuracy error of the hydraulic pressure control valve sample was 10% higher, and even after revising samples for 3 times, it still can not meet the machining allowance of 0.3mm. George has to face the technical shortcomings of the old manufacturer, the sample pushing of the customer, and the situation of no suitable hydraulic pressure control valve manufacturer to make samples. He contacted the all the hydraulic valve manufacturers cooperated in the past, but none of them was able to make a hydraulic pressure control valve with a machining allowance of 0.3mm. He kept looking for a new hydraulic pressure control valve manufacturer online and came across AAK hydraulic valve on B2B. George left a message on our website www.aakindustry.com: I saw AAK article introducing the hydraulic valve with machining allowance of 0.3mm. We have a hydraulic pressure control valve requiring machining allowance of 0.3mm. Can you sample it? For those customers who directly require to make samples like this, basically, they encountered the sample failure from other hydraulic pressure control valve manufacturers. After communication, we know that his old supplier has failed to deal with the 0.3mm finishing hydraulic pressure control valve samples for 3 times. After checking George's hydraulic pressure control valve drawings and various parameter descriptions, AAK engineers confidently informed that the sample could be successful at one time. George may think that only AAK can help him solve the problem. He directly paid a proofing fee of $1,200.00 and asked us to send the hydraulic pressure control valve samples within 3 weeks. We appreciated George's frankness and asked the workshop to cooperate fully. After 15 days, we successfully sent the samples of hydraulic pressure control valves. On the third day after George received the samples, he told us that the machining accuracy of AAK hydraulic pressure control valve not only met the requirement of machining allowance of 0.3mm, but also increased by 5%, which made him admire very much. In order to ensure the accuracy of finish machining size allowance, the heat treatment process is the most critical step. At present, most hydraulic pressure control valve manufacturers adopt local quenching, the workpiece heat treatment process is not easy to control, and most of them are easy to deform.