Cold drawing machine is a special machine that takes raw steel wire rod in its primary state and reduces its diameter for various applications. It can be used for metal mesh, welded constructions, industrial machinery, etc. The machine works on the principle of pulling from left (tension) rather than pushing from right (compression). The rod is pushed in front by a mandrel and lubricated with technological lubricant, which then goes through the drawing dies to achieve its final cross sectional area. The end product is a coil of the desired diameter.
The cold drawing process starts with the pointing of the lead ends of the bar or coil. This is done to make the section of the metal smaller so that it can pass freely through the drawing die. The lead ends are pointed using swaging or extrusion to reduce the section size to the size of the die opening. Usually, multiple passes through the drawing dies are required to get the desired shape. This is because the original material has a larger cross section than the die opening.
During the drawing process, the metal hardens and its strength properties increase. At the same time, plastic properties decrease. This is why it is necessary to build an accurate energy-power mathematical model of the drawing process, based on the hardening curves for each particular alloy. The calculation of these curves is a laborious task, but it is essential for the construction of an effective drawing machine.
For this purpose, experimental studies on a laboratory drawing machine are recommended. These studies should include the measurement of the force required for a given set of technological parameters such as the die half-angle, the friction coefficient, the drawing speed and the back tension. This will improve the accuracy of the energy-power model and enable it to predict the limiting values for the drawing process.
Moreover, the experiment should also include an analysis of the effect on the drawing process of technological parameters such as the mandrels front and back adjusting device, the core rod seat and the drawing die holder. It should also examine the influence of the various types of lubricants on these parameters. This will help the designers of a new drawing machine to choose the appropriate lubrication system.
In addition to these experiments, it is also recommended that the experimental study of the drawing machine should include the use of well-proven computer software packages such as QForm and ABAQUS. This will allow the engineers to optimize the design of the machine and increase its efficiency. Moreover, it will allow the operators to save money by eliminating unnecessary steps in the production cycle. This is especially important because non-value-added steps in the production process will increase operating costs and result in a lower quality finished product. This can be particularly damaging for manufacturers in the competitive market where the margins are very thin. Therefore, the optimal design of a drawing machine is crucial for maximizing the company’s profits.