Cold heading process

Cold upsetting is essential for mass production of automotive fasteners, motorcycles, bicycles, appliances profiled automated production method for producing the same cutting workers compared the metal fibers (metal flow lines) along the product the shape continuous grain no break, thus increasing the strength of the product, particularly excellent in mechanical properties, and raw material savings.

Rising as the environmental voice of the fasteners more industry more attention to environmental issues. Therefore, as a non-cutting forming cold heading technology are increasingly seeking high-strength, high-value-added.

This article lists near cold heading and cold extrusion composite technology developments.

1, the binding of stamping parts

The distance between the shape and the edge of the inner hole is smaller than the thickness of the punch and die, an inner diameter greater than the outer diameter of the half, the height is more than 1.5 times the inner diameter of the punching, the better binding stamping. Since the distance between the edge of the shape and bore closer, the the stamping punch needle force will affect the shape, the size of the shape changes. Must make this part of the shape is bound by the state in order to prevent changes Dimensions. Since the role of the binding force, stamping section is in a compressive stress state, in this punched compressive stress state, to take an appropriate gap can be obtained all bright band stamping effect.

2, cut extrusion

Generally, the bolt head of the plastic processing, of forming cold upsetting cut extrusion forming process has more advantages than rose shaped craft. Before the cut extrusion, rough shaping process requirements can be obtained by shaping rough. Rough size must be seriously rough shape before the squeeze is to be determined according to the situation of the part, using the rough shape of the material flow. Rough size is too large, cut squeeze the margin is too large, cut squeeze force to squeeze easily lead cut to reduce die life, and to increase the possibility of mold accidental damage, and consumption of raw materials; cutting squeezed margin is too small parts easy to cut squeeze off angle, the shape is incomplete, not satisfied with the appearance of quality.

Mold structure is focused on the design of the cut squeeze film processing, cutting edge work size best control in the lower limit, the cut extrusion die angle to the right, the edge must go through the grinding, polishing, the roughness Ra0.025 to Ra0.050 μ m, has the highest life expectancy.

3, drawing and forging forming

Bumps thick-walled parts with cold extrusion and deep drawing goblet shaped pieces into one plate material, drawing and compression the composite molding method and forming fasteners, forming characteristics forming and increased wall thickness of the head projection.

4, the local forming

Upsetting pressure molding there are two concepts, one plenary upsetting pressure, i.e. on the whole end face of the product has force; partial upsetting pressure, i.e. only in the necessary part of the applied pressure. Forming all the processing area, forming load, require large tonnage stamping machines, get the necessary thickness variation can be used for partial forming a lower load, holes, slots forming a wide range of applications.

Of ① steps parts

An example to illustrate the points forming applications, engineering design: design lathe - annealing - phosphorus saponification - extrusion (half sealed extrusion forming steps) to the connector.

② fine local forming

The need for locking and chip 1 to 3, for some set screws scraping groove machining, extrusion processes can be used, a representative is a grooved molding automobile combination bolt shavings.