The selection of the type of gantry punch is based on the technological properties of stamping, the size of production batch, the geometric dimensions and accuracy requirements of stamping parts, etc. the general principles of the selection of the type of punch are summarized as follows:

Punch equipment type and specification selection method

(1) In the production of small and medium-sized stamping parts, open punch is mainly used. The single column punch has the advantages of convenient operation conditions, easy installation of mechanized accessories and low cost; Open punch has the advantages of feeding and discharging in left and right directions. However, the stiffness of this kind of punch is poor, and the deformation of the bed can destroy the distribution of die gap under the effect of stamping deformation force. Reduce the life of the die or the surface quality of the blanking parts. In the production of large and medium-sized blanking parts, the closed punch is often used. Among them, there are general-purpose press, but also a small table and stiffness of the special extrusion press, precision press, etc. In the production of large drawing parts, double acting press can be used, the die structure is simple and easy to adjust.

(2) In mass production or mass production of complex shape parts, high-speed press or multi station automatic pressure grilling should be selected; In the small batch production, especially in the bending forming production of large thick plate stamping parts, high-speed press or friction press are often used. The hydraulic press has no I.Q fixed stroke, and will not overload because of the change of sheet thickness. When it needs a large force stroke, it has obvious advantages compared with the punch press. However, the production efficiency of hydraulic press is low, and the dimensional accuracy of stamping parts is sometimes unstable due to the influence of operation factors. Friction press has simple structure, low cost and is not easy to be damaged by overload. It is often used to complete bending and other stamping work. Because the stroke of the friction press is not fixed, it is not affected by the fluctuation of sheet thickness in the leveling or shape correction of stamping parts, and can maintain a relatively stable shape correction accuracy. However, the friction press has less stroke times, low production efficiency and inconvenient operation.

(3) Pay full attention to the rigidity and accuracy of the press. The rigidity of punch press is composed of bed rigidity, transmission rigidity and guide rigidity. Only when the stiffness of the press is enough, its static accuracy (the accuracy measured at no load) can be maintained under the condition of load, otherwise, its static accuracy will lose its significance. The stiffness of the press directly affects the life of the die and the quality of the blanking parts. The punching machine with high precision and high rigidity should be selected as far as possible. The punch used for correcting bending, flattening and shape should have greater rigidity to obtain higher dimensional accuracy of stamping parts.