Cold forging machines, or cold forging press machines, are the forming press that can cut and shape the wire through a series of dies. Forming presses are also called machine presses, which are tools that are designed to deform the workpiece under high pressure.
After positioning the workpiece, machine presses will push shaping dies or plates onto or against the targets with high pressure. The cold forging presses are usually horizontal presses which perform the forming production at room temperature. The wires or plates are fed into the cold forging press machine and subsequently cut to proper lengths, and eventually pass through the tools to form the desired shapes. While shaping, the materials are pressed and squeezed between dies to create primary shape. After going through the rolling, drawing, pressing, rotating, extruding and heading process, the cold forging extrusion can produce a high quality finished piece.
Cold forging press machines typically have a cutoff capability of material diameter ranges from 0.2cm to 5cm and a feed length capability ranges from 0.2 cm to 30cm and more. There are also various types of feeder and conveyor depending on the application and the materials. Cold forging press machines are popular equipment in common industrial manufacturing. For example, they are commonly used in automobile components production lines.
Cold forging process in the press machine is one of the most commonly used forming methods because no chip is created in the process. The definition of cold forging is the forming of the bulk materials without consistently heating and processing at high temperature and heating of the initial slug. Forming at room temperature, the term “cold” and “without heating” do not include the annealing process. Annealing treatment can increase the ductility and relieve the hardness of metals at intermediate stages in cold forging press machines.
Compared to hot forming or warm forming, cold forging process features better dimensional accuracy, and the fact that scale is not created during cold forging. However, the cold forging process is less suitable for plastic parts forming application and the characteristics of the plastic flows. In this case, higher forging pressures are required. The size of the materials is generally limited to 22 kg or less. Typically, the cold forgings weigh less than 5 kg. Materials that are suitable for cold forging include, but are not limited to, alloy steels, carbon steels, nickel steels, brass, copper, lead, bronze, aluminum, and also precious metals.
For starters, hot forging processes perform at high temperature up to 1150 °C for steels and approximately 500 °C for al-alloy steels and 700 °C for cu-alloy steels. The extreme high temperature is the key to avoid the metal from strain hardening during the forming process. The most common application of this type of deformation is stamping, which uses a tool and a die surface to squeeze the materials in press machines.
Cold forging process may be preferred over hot forging because cold forged pieces require little or even no finishing work. All the parts are annealed before forging, so the need for secondary heating before machining is eliminated. Another advantage of cold forging press machines lies in materials saving. Through near net shapes, the original weight equals the final weight of the cold forged parts. In addition, cold forging provides ideal level of dimensional accuracy and ideal surface quality. Moreover, the high efficiency with high production rate and clean environment during cold forging and the tool longevity can all effectively cut the cost.
Although many manufacturers preferred cold forging, some features of cold forging pressing might turn out disadvantages. For example, if the manufacturers are looking for specific customized parts forging, the achievable shaping levels are limited compared to stamping. Cold forging is much more suitable for mass production of simple shapes. Also, metal parts deformed by cold forging are less ductile and might be less suitable for certain configurations. Since the grain structure provides the strengths to the materials, it is possible that the residual stress will occur. As a result, cold forging press machines cannot be utilized on every steel grade. Materials with low ductility and sensitivity to strain hardening are less suitable in this type of deforming methods.
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