Cold drawing machine involves a series of steps where steel bars are drawn (pulled) through a die to achieve the desired cross sectional area. The lead ends of the steel bar are submerged in lubricant to reduce friction and make it easier for them to pass through the die.
The draw process can involve several passes through smaller and smaller dies to shape the profile and increase ductility. The finished product exhibits a bright finish, improved mechanical properties and precise and consistent dimensional tolerances.
The cold drawing process pulls the raw material through a series of dies to reduce its size. This produces a bright and polished finish, improved mechanical properties, dimensional tolerances and a uniform shape. The final product is stronger and tougher than the original hot rolled stock.
The first step in the process is to remove abrasive scale from the surface of the raw steel rod or coil. Then the rod is coated with a drawing lubricant to aid in the drawing process.
During the drawing process, the dead block must be held still. A gooseneck arm, hydraulically adjustable die box and a fixed position mandrel are commonly used to hold the block. In addition to holding the block, this arrangement also imparts a twist to each wrap of wire leaving the capstan. This twist must be managed to avoid a snarl that could disrupt the process. Depending on the application, this twist can be eliminated by using an accumulator block or by forced air-cooling of the capstan.
Metalworking companies that use cold drawing often work with a wide variety of materials, including carbon steel, low-alloy steel, stainless steel, copper and aluminum. This type of drawing reduces the cross-section size of these metals and shapes them to fit into pre-determined dies. Several passes through these dies can produce a finished product that meets strict dimensional tolerances and requirements.
To begin the process, the material is submerged in a lubricant. This prevents the material from becoming stuck in the dies. In addition, it helps make it easier for the material to pass through the dies. After the lubricant is applied, the lead ends of the steel bar or coil are reduced in length to allow them to pass more easily through the dies.
In addition to the standard operator interface with a large display screen, these systems have the ability to connect to a plant-wide data network. This allows real-time monitoring of production data with the ability to generate trouble alarms and e-mail alerts.
Drawing is not without its risks. When the angular speed of the capstans doesn’t match the linear speed of the wire, the result is slip between the capstan and the wire (see FigB15). This causes heat and back tension that requires additional draw force, which adds to overall stress on the machine. To reduce this, a machine builder must select materials, hardening methods and capstan designs appropriate for the wire products to be drawn.
Rod payoff is another issue that needs attention to maintain a consistent, controlled and accurate method of paying off the rod from each block on a straight line drawing machine. This method eliminates erratic sheave and dancer roll oscillation that can cause snarls in the wire bundle or wire breaks in succeeding blocks.
Other safety issues include a means of stopping the machine quickly, as well as the need for proper electrical wiring between motor drives and the PLC. Modern machines employ the use of high-speed data buses to transmit control signals over a single pair of wires, rather than using individual wires for each drive motor.
A cold drawing machine needs to operate in an environment that is conducive to its operation. This means that the room in which it is placed should be clean, and the fugitive emissions from the process need to be contained by properly installed air ducts that evacuate burned soap and dust to a central filtration plant. The machine should be fitted with guards that minimize the escape of these emissions, and protective equipment should be worn by all personnel operating the machine.
In order to solve the problems of existing cold-drawing mechanism, which are large investment, certain limit on the length of wires and incapability to make effective use of raw materials, the utility model provides a kind of simple and easy metal wire drawing mechanism that is used on stretching-machine. This mechanism consists of a stretching anchor portion 6, mould fixing end portion and gland; the drawing wire rod passes through charging window, the axially communicated charging hole with wear the nib three and fixes with the gland; under the effect of stretcher tractive force, the wire rod carries out the cold-drawn metal drawing deformation processing through fixed mould.