There are currently about 12,600 die-casting enterprises and those related to die-casting in China, among which over 70% are engaged in the production of die-cast parts. Alloy, die-casting machine, mold, smelting equipment, coating, testing equipment, various raw materials, peripheral equipment, die-casting machine parts and other enterprises account for about 30%. The output of domestic die-castings has long ranked first in the world, and the gross domestic product has reached 50 trillion yuan.

Among enterprises of all forms of ownership, large-scale ones have an annual production capacity of 10,000 tons of die-castings, with the largest reaching 60,000 tons. Medium-sized ones can produce around 5,000 tons of die-castings annually, and small-scale ones also have an annual production capacity of several hundred tons. The proportion of various die-castings in the total volume of die-castings is approximately 83% for aluminum alloy, 15% for zinc alloy, and 2% for zinc alloy. Among them, about 5.6 million tons of die-castings such as aluminum alloy were produced in 2014.

The main output of die-cast parts products is mainly for automotive and motorcycle parts. The die-cast parts used in each car include transmission housing, cylinder block, and crankcase quasi-die-cast parts. On average, each car uses 75 kilograms of die-cast parts, and the total weight accounts for more than 50% of the overall domestic die-cast parts production.

The manufacturing precision requirements for die-castings are extremely high, mainly including multiple processes such as grinding, cutting and welding.

In CNC centers, five-axis and three-axis CNC machine tools are mostly used for processing and production. The design of such high-precision machine tools mostly adopts a series of high-precision pneumatic actuating components such as cylinders. Influenced by traditional craftsmanship, the finished products produced by most casting manufacturers often have a high defect rate, and the processing accuracy is difficult to meet the requirements. Moreover, such problems have never been effectively solved. Many enterprises are puzzled: Why is it that the processing accuracy of the same imported machine tools produced domestically is so far behind that of those from abroad?

After searching for the reasons from multiple sources, it was finally discovered that the timeliness and accuracy of the actions of a series of pneumatic components such as cylinders in CNC machine tools are crucial to the precision of processing, and the actions of pneumatic components are closely related to the quality of the air source. However, in the configuration of the air compression system in most existing die-casting factories, the most traditional drying method, that is, the post-cooling dryer for cooling and drying treatment, is still adopted. The pressure dew point of the compressed air after cooling and drying is generally between +10℃ and +15℃(higher than the requirements of Grade 6 in the mechanical industry standard JB/T5967-2007).

The pneumatic components used on high-precision CNC machine tools are clearly required to have a pressure dew point below +3℃(meeting the requirements of Grade 4 in the mechanical industry standard JB/T5967-2007), and the moisture content in the compressed air seriously exceeds the equipment requirements.

After identifying the cause, the post-treatment equipment was immediately rectified. The original refrigerated dryer was replaced with a mold core adsorption dryer. The pressure dew point after the replacement can reach -20℃, fully meeting the production requirements. One month later, statistics and analysis were conducted on the precision of defective products and processed finished products. It was found that the number of defective products had decreased by 5%, and the precision had also greatly improved.