Cold heading forming process for seamless chain roller and punch pin head for cold heading forming bottom punching

Abstract

The invention discloses a cold heading forming process for a seamless chain roller and a punch pin head for cold heading forming bottom punching. The cold heading forming process for the seamless chain roller comprises the steps of feeding, cutting, flat heading, blank heading, inversion, head punching, inversion, secondary punching and bottom punching; the depth of the head punching after the blank heading and the inversion is controlled in a range of 2 to 5 millimeters; and the reserved bottom thickness of the secondary punching after the inversion is controlled in a range of 0.5 to 2 millimeters. The punch pin head for the cold heading forming bottom punching comprises a front head of a cylindrical surface, and the rear part of the front head (10) of the cylindrical surface of the punch pin head is a raised spherical surface (20). By combining the cold heading forming process and the punch pin head, one-time precise cold extrusion forming of workpieces can be finished, staggered metallographic structures in the metal and defective metallic plastic formed metal streamlines are repaired, and the mechanical property of a product is further improved.

Description

technical field [0001] The invention relates to a seamless chain roller cold heading forming process and a punching needle used for cold heading bottom punching, belonging to the technical field of mechanical manufacturing. Background technique [0002] It is used as a cold heading forming machine for metal upsetting at room temperature, and is widely used in manufacturing. At present, the forming process of the cylindrical seamless chain roller (bush) in the multi-station cold heading forming machine is: feeding and cutting material, upsetting, upsetting embryo 1, reverse, head punching, 2, reverse, two punching, 3 Bottom 4 (see figure 1 ). Since the depth of the head punch is usually controlled at 1 / 2 of the workpiece, when the head punch is reversed and the second punch is performed, the thickness of the bottom is controlled within the range of 2-4mm, and because the head punch and the second punch are Two equal extrusions in different directions lead to the opposite f...

AI Technical Summary

Problems solved by technology

Since the depth of the head punch is usually controlled at 1 / 2 of the workpiece, when the head punch is reversed and the second punch is performed, the thickness of the bottom is controlled within the range of 2-4mm, and because the head punch and the second punch are Two equal extrusions in different directions lead to the opposite flow direction of the plastic forming of the metal workpiece and the imbalance of the force point, which is easy to form concave and convex lines on the outer surface of the workpiece, which affects the quality of the outer surface of the workpiece; at the same time, due to the final bottom punching The position is in the middle of the inner hole of the upsetting blank, so the punched negative film and the debris brought out have a longer stroke in the inner hole of the upsetting blank, which is easy to cause damage to the inner wall of the inner hole of the upsetting blank and affect the glossiness of the inner surface of the product ; In addition, since the punching needle head used by the cold heading forming machine in the final punching bottom is a cylindrical surface (see figure 2 ), its diameter is the same as the inner diameter of the inner hole of the punched and upset blank, so when the inner hole wall of the punched and upset blank is in contact with it, it will often be slightly worn, causing scratches on the surface of the inner hole wall, and the inner hole of the upset blank It is not one-time molding, and the "step mark" caused by deviation will be left when the needle passes through the inner hole successively. Different models have different heights of the step marks in the inner hole of the product. Some products have steps with a height of 0.3mm, which seriously affects the quality of the product.

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