A wire drawing machine is also known as a drawing machine or wire drawer. It is a piece of common mechanical equipment in industrial applications, which is widely used in machinery manufacturing, hardware processing, the petrochemical industry, plastics, bamboo and wood products, the wire and cable industry, and other industries.
Working Principle of The Wire Drawing Machine
Wire Drawing Process
Wire is prepared by shrinking it to fit into the die by hammering, filing, rolling, or hammering, and then the wire is pulled through the die. The volume of the wire remains the same as it is drawn through a die, so the length increases as the diameter decreases. It is usually necessary to draw the wire through successive smaller dies to reach the desired size. The American wire gauge is based on this. This can be done on a small scale with a wire drawing plate or on a large commercial scale using automatic machines. The wire drawing process changes the material properties due to cold working.
The area reduction is usually around 15–25% for small wires and 20–45% for larger wires. The exact die sequence for a particular job is a function of the area reduction, the inlet wire size, and the outlet wire size. The die sequence changes as the area reduction changes.
Very fine wires are usually drawn in bundles. In a bundle, the wires are separated by a metal of similar properties but less chemical resistance, so that they can be removed after drawing. If the area reduction is greater than 50%, an intermediate annealing step may be required before redrawing.
Commercial wire drawing usually begins with a 9 mm diameter hot rolled coil. The surface is first descaled. It is then fed into a wire drawing machine, which may have one or more blocks in series.
Single block wire drawing machines include means for holding the dies in position correctly and for drawing the wire smoothly through the holes. The usual design consists of a cast iron bench or table with a standing bracket to hold the die, and a vertical drum which rotates and draws the wire through the die by winding it around its surface, the coil of wire being stored on another drum or “fast” located behind the die, which winds the wire as fast as required. The wire drum or “block” is provided with means for quickly connecting or disconnecting it from its vertical spindle, so that the movement of the wire can be stopped or started instantly. The block is also tapered, so that the coil of wire can be easily slid up when finished. Before the wire can be connected to the block, it must be drawn through the die to a sufficient length; this is accomplished by a pair of grippers at the end of a chain wound around a rotating drum, so that the wire is drawn enough to wrap two or three times over the block, to which the end is secured by a small screw or vice. The wire is set in motion while on the block, and the wire is drawn steadily through the die; it is very important that the block rotates evenly and operates accurately and draws the wire at a constant speed, otherwise “grabbing” will occur which will weaken or even break the wire. The speeds at which the wire is drawn vary greatly with the material and the amount of reduction.
Continuous drawing machines differ from single drawing machines in that they have a series of dies through which the wire is drawn continuously. Due to elongation and slippage, the speed of the wire changes with each successive redraw. This increased speed is achieved by having a different rotation speed for each draw. These machines may contain from 3 to 12 dies.[2]
Intermediate anneals are often required to counteract the effects of cold working and to allow for further drawing operations. A final anneal may also be performed on the finished product to maximize ductility and electrical conductivity.
An example of a product produced on a continuous wire drawing machine is telephone wire. It is drawn 20 to 30 times from hot-rolled bar stock.
Although round sections dominate most drawing operations, noncircular sections are also drawn. They are usually drawn when the cross-section is small and quantities are too low to justify rolling. A single-draw or square-lay machine (Turk’s-head machine) is used in these operations.
Lubrication
Lubrication is essential in the drawing process to ensure a good surface finish and long die life. The following are different methods of lubrication:
Wet wire drawing: The dies and wire or rod are completely immersed in lubricants.
Dry drawing: The wire or rod is passed through a container of lubricant that coats the surface of the wire or rod.
Metal coating: The wire or rod is coated with a soft metal that acts as a solid lubricant.
Ultrasonic vibration: The dies and mandrels are vibrated, which helps reduce forces and allow greater reductions per pass.
Various lubricants, such as oil, are used. Another method of lubrication is to dip the wire in a copper(II) sulfate solution, which deposits a copper film on the surface after immersion, acting as a type of lubricant. In some wire grades, the copper is left on after the final drawing to prevent rusting or to facilitate easy soldering. The best example of copper-coated wire is gas metal arc welding (GMAW, MIG) wire used in welding.
Mechanical Properties
The strength-enhancing effect of wire drawing can be significant. The highest strengths available in steels are recorded on small diameter cold drawn austenitic stainless wire.
Wire Drawing Dies
Wire drawing dies (rolls) are usually made of tool steel, tungsten carbide or diamond; tungsten carbide and synthetic diamond are the most common. A single-grain diamond die is used for drawing very fine wire. Cast steel dies are used for hot drawing. A tungsten carbide dies are used for drawing steel wire. The dies are placed in a steel housing that supports the die and allows for easy die change. Each die has at least 2 different angles: the entrance angle and the approach angle. Die angles usually vary between 6-15°.
Diversified Application Scenarios of Wire Drawing Machines
Metal Processing Field
In the metal processing industry, wire drawing machine is one of the important equipment. It can draw metal wires such as copper, aluminum, and stainless steel to reduce their diameter and increase their length, while improving the mechanical properties of the metal. For example, in the production of wires and cables, raw materials such as copper and aluminum are processed into wires of different specifications by wire drawing machines for the manufacture of wire cores, cable conductors, etc.; in the production of hardware products, metal wires can be drawn into steel wires of various specifications for the manufacture of springs, nails, screws, etc. In addition, wire drawing machines can also be used for the drawing of metal pipes to produce high-precision metal pipes, which are used in aerospace, automobile manufacturing, and other fields with high requirements for pipe precision.
Electronic Information Industry
In the electronic information industry, wire drawing machines have unique application scenarios. With the miniaturization and precision development of electronic components, the requirements for the precision and quality of metal wires are getting higher and higher. Wire drawing machines can draw metal materials into extremely fine wires, such as gold wires, silver wires, etc., which play a key role in electronic packaging, integrated circuits, semiconductor manufacturing and other fields. For example, in the chip packaging process, extremely fine gold wire is needed to connect the chip to the package shell to achieve electrical connection; in the manufacture of printed circuit boards (PCBs), high-precision copper foil wires produced by wire drawing machines are used to make the conductors of circuit boards. In addition, wire drawing machines can also be used to produce connecting wires inside electronic devices, radio frequency coaxial cables, etc.
Building Decoration Industry
In the building decoration industry, the application of wire drawing machines adds more possibilities to building decoration. Through the wire drawing process, metal sheets, pipes, etc. can be surface treated to give them a unique wire drawing texture and increase the decorative effect. For example, in interior decoration, stainless steel wire drawing plates are often used for the decoration of walls, floors, and ceilings to create a modern and simple style; aluminum alloy wire drawing profiles can be used to make doors and windows, stair handrails, railings, etc., which not only have good corrosion resistance, but also enhance the beauty of the building. In addition, in outdoor building decoration, wire drawing metal sheets can be used for curtain wall decoration to make the appearance of the building more fashionable and atmospheric.
Aerospace Field
The aerospace field has extremely strict requirements on the performance of materials. The application of wire drawing machines in this field is mainly reflected in the processing of special metal wires. The metal wires used in aerospace equipment need to have high strength, high temperature resistance, corrosion resistance, and other characteristics. The wire drawing machine can draw special metal materials such as titanium alloys and nickel-based alloys to produce wires that meet the requirements. These wires are widely used in aircraft structural components, engine parts, and spacecraft connection devices. For example, steel wires for aircraft landing gear and high-temperature alloy wires in engines all need to be precisely processed by wire drawing machines to ensure that their performance meets the strict requirements of the aerospace field.
Jewelry Making
In the jewelry making industry, wire drawing machines are one of the indispensable tools. It can draw precious metal materials such as gold, silver, and platinum into wires of different thicknesses for making various exquisite jewelry. Through the wire drawing process, delicate chains, exquisite patterns, and complex structures can be produced. For example, common gold necklaces, silver bracelets, etc. are usually woven or welded from precious metal wires that have been wire drawn; in jewelry inlays, fine gold wires can be used to fix gemstones to increase the firmness and beauty of jewelry. In addition, wire drawing machines can also be used to make jewelry accessories with unique textures, such as wire-drawn pendants and earrings, to meet the aesthetic needs of different consumers.
Medical Device Manufacturing
Medical device manufacturing has extremely high requirements for the safety and precision of materials. Wire drawing machines are mainly used in this field to process medical metal wires. Medical stainless steel, titanium alloy and other materials have good biocompatibility and corrosion resistance. Through the processing of wire drawing machines, medical wires of various specifications can be made, such as sutures, guide wires, stent wires, etc. For example, medical sutures are usually made of extremely fine stainless steel wires or nylon wires. Wire drawing machines can ensure that the wires have uniform diameters and smooth surfaces, reducing damage to human tissues; guide wires and stents used in vascular interventional surgery need to have good flexibility and support. The high-precision wires processed by wire drawing machines provide guarantees for their performance. In addition, wire drawing machines can also be used to make springs, buckles, and other parts in medical devices.
Practical Tips for Efficient Maintenance of Wire Drawing Machines
Daily Cleaning and Maintenance
Regularly remove metal debris, oil and dust from the surface and inside of the wire drawing machine to prevent impurities from entering the transmission system or affecting the heat dissipation of the equipment. Focus on cleaning the parts that directly contact the wire, such as the wire drawing die and reel, which can be purged with compressed air or wiped with a special cleaning agent. After cleaning, check whether the moving parts are flexible to ensure that there is no foreign matter blocking them.
Lubrication System Maintenance
Regularly add lubricating oil: According to the requirements of the equipment manual, regularly add lubricating oil or grease to the lubrication points such as gear boxes, bearings, and guide rails to ensure that the lubrication system is unobstructed. Pay attention to the lubrication cycle and oil model of different components to avoid mixing.
Check the oil status: Check the oil level, color, and viscosity of the lubricating oil every week. If the oil is found to be deteriorated, emulsified or has too many impurities, it needs to be replaced in time. At the same time, clean the impurities deposited at the bottom of the oil tank to prevent blockage of the oil circuit.
Wire Drawing Die and Reel Maintenance
Wire drawing die inspection: Check the wear of the die hole before each start-up. If the hole diameter is found to be larger, the surface is scratched or the roughness is reduced, it needs to be replaced or polished and repaired in time. Wipe the mold with a soft cloth after use and apply anti-rust oil to prevent rust.
Reel maintenance: Regularly check whether there are grooves, wear or cracks on the surface of the reel, and polish the worn parts in time. Clean the wire lubricant remaining on the reel to avoid affecting the surface quality of the wire after hardening.
Electrical System Inspection
Line inspection: Check whether the electrical circuit connection is firm every month, whether there is looseness, aging or damage, replace aging cables in time, and tighten the terminal blocks to prevent short circuit or poor contact from causing failure.
Control system maintenance: Clean the dust in the control cabinet, check whether the contacts of each relay and contactor are normal, and whether the cooling fan is running well. Regularly test the reliability of safety devices such as emergency stop buttons and limit switches.
Transmission System Maintenance
Gear and belt maintenance: Check whether the gear meshing is normal, whether there is abnormal noise or abnormal wear, regularly clean the iron filings in the gear box and replace the lubricating oil. For belt transmission devices, the belt tension needs to be adjusted. If the belt is found to be aging or cracked, it needs to be replaced in time.
Bearing status monitoring: Determine the operating status of the bearing by listening to the sound, measuring the temperature, etc. If abnormal noise, overheating, or increased vibration is found, it is necessary to disassemble and inspect and replace the worn bearing, and add an appropriate amount of grease.
Replacement and Adjustment of Wearing Parts
Replace wearing parts in time: Regularly check the wear of wearing parts such as guide wheels, wire guide nozzles, tension sensors, etc., and replace them in time according to the use cycle to avoid wire quality problems or equipment failures due to component failure.
Adjustment of tension system: Calibrate the tension control system according to the wire specifications and process requirements to ensure stable tension during the wire drawing process. Regularly check the sensitivity and accuracy of the tension sensor, and calibrate or replace it if necessary.
Machine Operation Test
Perform a machine operation test once a week to observe the operating status of the equipment at different speeds and loads, and check whether the parameters of each system (such as temperature, pressure, and speed) are normal. Pay attention to whether there is abnormal vibration, noise, or odor during the test, and stop the machine in time to check if problems are found to avoid the expansion of faults.
Establish Maintenance Files
Record the time, content, replaced parts and equipment operating status of each maintenance to form a complete maintenance file. By analyzing historical data, summarizing equipment wear patterns and failure trends, and formulating preventive maintenance plans in advance, the service life of equipment can be extended, and production efficiency can be improved.
How to Choose a Wire Drawing Machine
Production Demand Analysis
Before choosing a steel wire drawing machine, you first need to clarify your production needs. This includes:
Wire diameter: Different machines are suitable for different ranges of wire diameters. Make sure the selected machine can meet your specific needs.
Wire strength: Understand the strength of the wire you need to produce and ensure that the machine can provide the required drawing force.
Output: Consider your daily and monthly production goals and choose a machine that suits your output needs.
Machine Type
Wire drawing machines are mainly of two types: single-hole and multi-hole:
Single-hole machine: suitable for small batch production, high flexibility, but relatively low efficiency.
Multi-hole machine: suitable for large batch production, high efficiency, but low flexibility. When choosing, you should make a reasonable judgment based on your production scale and plan.
Automation
Modern wire drawing machines are becoming more and more automated, with the following advantages:
Reduced human intervention: Highly automated machines can reduce human errors and improve production efficiency.
Real-time monitoring: Some machines are equipped with data monitoring systems that can track production indicators in real time, make timely adjustments, and improve production stability.
Maintenance and Support
Choosing a reliable supplier is crucial. You need to consider:
After-sales service: Understand the technical support and maintenance services provided by the supplier to ensure that you can get timely help when there is a problem with the equipment.
Spare parts supply: Choose a supplier that can quickly provide spare parts to reduce equipment downtime.
Energy Efficiency
Energy-saving machines can not only reduce operating costs but also enhance the company’s sustainable development image. When choosing, you can pay attention to the following aspects:
Energy consumption standards: Choose machines that meet national or regional energy consumption standards.
Energy-saving technology: Some new machines use advanced energy-saving technologies to significantly reduce energy consumption.
