What Is a Cold Forging Press?
Cold forging press is one of the plastic working methods for metal materials.
There are three major types of metal processing:
- Cutting Process
It is a method of removing parts that are not needed for a shape from a large block of material by shaving or cutting with a blade or other tool. - Casting Method
The material is heated to melt, poured into a shape that inverts the product shape, and then cooled to solidify. - Forging
This method involves pounding metal into a mold in its solid state and applying pressure to the material to create a shape.
Cold forging presses are a particular type of forging in which the material is not heated, but is instead tapped into the die and formed at room temperature.
Uses of Cold Forging Presses
Cold forging presses are used to manufacture parts that require particularly high mechanical properties. In automotive parts, it is useful for manufacturing shaft parts for power transmission and various other parts, including bolts that require high strength.
In addition to automotive parts, other applications include the manufacture of parts for electrical appliances and office automation equipment, as well as handle shafts for residential door parts.
Principle of Cold Forging Presses
Cold forging presses are broadly divided into vertical and horizontal presses. Vertical press machines are used in cold forging presses.
There are several types of presses: crank presses, knuckle joint presses, screw presses, and hydraulic presses. The most suitable press for cold forging is the knuckle joint press.
1. Crank Press
A crank press is a press machine that converts the rotational energy of a flywheel into the vertical reciprocating motion of a ram via a crank mechanism. It is suitable for sheet metal presses.
Due to its structure, the load capacity is low when the ram is near the upper dead point, and the load cannot be held. For use in cold forging, it should be able to maintain a constant load near the bottom dead center.
2. Knuckle Joint Press
The knuckle-jointed press is a toggle mechanism in which the axis of rotation of the crank is shifted to the side instead of being placed vertically, in order to change the characteristics of the motion near the bottom dead center of the ram. As a result, the press descends near the bottom dead center and rises quickly.
Each manufacturer has developed its own crank-link mechanism, which is offered as a cold forging press. Horizontal presses are generally used for mass production.
An example is FORMA. The former is a highly productive multi-stage press using a piston-crank mechanism, with multiple punch and die pairs arranged side by side.
Most screws are formed in formers and then threaded using a process called thread rolling, followed by surface treatment such as heat treatment and plating.
Features of Cold Forging Press
Products made by cold forging presses have the following characteristics:
1. High Mechanical Properties
Cold forging press is a plastic forming process that applies pressure to deform metal to form a fibrous structure called a forged line or fiber flow line. The continuous fibers provide high strength and wear resistance.
2. No Need to Use Unnecessary Materials
In cutting, the material removed by machining is wasted if it remains intact. In forging, no material is wasted because there is no material to be removed.
3. Suitable for Mass Production
Cold forging enables mass production in a short time by supplying materials one after another. 100 products can be produced in a minute.
4. Low Production Cost
Production costs can be lowered because materials can be used without waste and production efficiency is high. However, since molds are expensive, production costs can be reduced only in the case of mass production.
Other Information on Cold Forging Presses
Difference Between Forging and Heading
A term similar to forging is heading. Forging generally refers to the application of pressure in the vertical direction, while forging generally refers to the application of pressure in the horizontal direction.
In addition to cold forging, there is also warm and hot forging. The higher the temperature of the material, the lower the metal’s resistance to elementary deformation and the more complex the shape can be made. Warm forging is performed by heating the material to between 600°C and 850°C, while hot forging is performed by heating the material to about 1,200°C.