Hot and Cold Forming Machines

Hot forming machines form metal that has been preheated. Cold forming machines form metal that has not been preheated. There are many types of hot forming machines according to the type of wok they do. Examples include a hot stamp machine or hot stamping machine, hot wire machine, hot foil stamping machine and a hot press machine. In a hot stamp machine or hot stamping machine, the metal is hot worked by localized compressive forces exerted by manual or power hammers, or presses. A hot wire machine is used to draw out sections of a bar stock, reducing diameter and increasing the length. A hot wire machine can also perform the opposite action. A hot foil stamping machine is used to squeeze the metal into very thin foils. A hot press machine employs a slow squeezing action to deform the metal to be formed. Like hot forming machines, there are also several types of cold forming machines. Examples include a cold roll forming machine and a cold heading machine. Sheets, strip, bars, and rods are cold-rolled by a cold roll forming machine to produce products which have smooth surfaces and accurate dimensions. A cold heading machine combines upsetting and extruding operations to form large-head, small-shank parts. Hot forming machines are extensively used for hot working processes as they drastically alter the shape of the metals without causing them to rupture. Cold forming machines are used for cold working processes that are carried out at room temperature.

There are several ways in which cold forming machines and hot forming machines function. In a cold roll forming machine, by changing the rolls a single machine may be adapted to roll many different shapes. Cold-rolled sheets are classified as skin-rolled, ¼ hard, ½ hard, or full hard. A cold roll forming machine is usually not economical for less than 10,000 feet of product per day. A cold heading machine is used to form large heads and small-shank parts because upsets can involve 6 to 10 diameters head rather than the 4½ diameters maximum. Upsetting and extruding, however, are separate operations, so maximum deformation of a blank must be figured separately for upsetting and extruding limits even with multi-station headers. A cold forming machine can be used for squeezing, bending, shearing, and drawing of cold-worked metal. A hot forming machine can be used for forming relatively thick-walled parts, having a cylindrical shape, by causing heated metal to be drawn through the opening between a die and a punch. A hot forming machine can also be used for hot spinning. Spinning is the forming of metal parts from a flat, rotating disk by applying controlled pressure to one side and causing the metal to flow against a rotating male form, which is held against the opposite side. A hot forming machine can be used for rolling, forging, pipe welding, piercing, drawing, extrusion, and spinning of hot-worked metals. Cold forming machines have better reproducibility and interchangeability of parts than hot forming machines.

Cold forming machines and hot forming machines are used in many applications. Examples include their use in rolling, swaging, bar and tube drawing, wire drawing, and bending. Cold forming machines and hot forming machines should adhere to various standards specified by the American Society of Mechanical Engineers (ASME).

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