Modern die industry enjoys the reputation of “evergreen industry” and is the criterion to judge industrial level of modern cities. The cities with advanced die industry in China are as follows: Shanghai “Yangtze River Delta” area, Huangyan and Ningbo in Zhejiang, and Shenzhen, Dongguan and Zhonshan, etc in Guangdong. All die plants invest to purchasing various processing centers, numerical-control milling machines and precision EDM, etc for better and more efficient production, which enhances die manufacturing precision and efficiency to a large extent. However, most manufacturers neglect the most fundamental link during the die manufacturing, i.e. fitting. As a result, the current fitting technique is still the same as that in the 20th century, i.e. manual rollover and knocking for medium- and small-sized dies, while forcible rollover and knocking in the mode of free falling body with various hanging machines for large-sized dies. Fitting of this kind will cause non-repairable damage and hidden hazards to finished dies.

I. Large noise that pollutes the working environment;

II. Tremendous consumption of physical strengths of laborers, which may cause various industrial accidents;

III. Die bases are always made from medium steel. The medium steel is comparatively soft, while the area of die is comparatively large. Therefore, knocking of bar copper with large forces will cause deep drop pits in surfaces of die bases, and seriously affects appearance quality of dies. Besides, the stamping effects of lead red in parting surfaces of dies also differ with different dropping points of the bar copper. Correct judgment of stamping effects of lead red during fitting can only depend on experience and basic skills of laborers. Different die laborers have different experience and judgment levels, and it will cause flask, faulty dieing or immoderate dieing of products after injection dieing, which increases times of die setting and delays construction period.

As for large-sized dies, fitting effects cannot be obtained only through human power, so fitting of large-sized dies are more complex and dangerous. First, dies shall be rolled over forcibly with lifting appliance, and then be lifted away for fitting in the mode of free falling body. Large inertia and impacting force produced during fitting cause tremendous damages to lifting appliances and potential damages and threats to operators.

In countries with advanced industry, such as America, Japan and Germany, etc, people have realized the above problems early in the end of the 20th century and developed the fitting products of the first generation, i.e. traditional pressure-plate-type die-locking clamping machine. The fitting machines were utilized in die production and manufacturing soon, which greatly enhance manufacturing precision and efficiency, and brought a revolution in die manufacturing technology. At present, some large- and medium-sized enterprises in China also realize the importance and necessity to replace manual knocking and forcible rollover with die spotting machine and die rolling machine, and substitute traditional and out-of-date fitting technique with advanced machines and appliances gradually, so as to realize convenience, safety and reliability.