Wire drawing aluminum involve many processes and techniques. This guide will teach you the best wire drawing process, technique, applications, advantages and disadvantages.
So, if you want to learn more on this technique, read this guide.
What Is Wire Drawing Aluminum?
Aluminum wire drawing is a fabrication procedure whose goal is to decrease the wire’s cross-sectional area. You do this via pulling through one or more drawing dies.
You conduct wire drawing of aluminum at room temperature, making it a cold working process. However, it is possible to conduct the process at higher temperatures especially when dealing with large diameters.
Aluminum Wire Drawing Process
The wire drawing process of aluminum allows you to create flexible wires by drawing through multiple and progressively smaller dies. The two most popular materials used to make these dies are diamond and tungsten carbide.
The wire drawing procedure for aluminum encompasses the following steps:
You clean the stock to avoid destruction of the draw die and work piece. Activities such as shot blasting or chemical pickling are necessary to remove impurities on the aluminum surface such as scales.
Lubrication of the aluminum surface is necessary to facilitate cold drawing. Some of the lubricants you employ in drawing are certain oils and phosphates.
When commencing the aluminum wire drawing process, you reduce the stock’s diameter at one end. This is pointing and it allows the stock to fit through the draw die. You can achieve pointing through turning, rolling or swaging.
Here, the drawing machine’s gripping tool receives the aluminum stock’s pointed end through the die. The machine then pulls the bar’s remaining portion through the die in a process we call drawing. Typically, the process extends the stock’s length while decreasing its cross section.
You achieve greater machining capabilities, improved mechanical properties, and accurate and consistent dimensional tolerances through wire drawing aluminum.
Sometimes a single drawing process is not enough given the profile complexity of a work. Consequently, to obtain the appropriate shape and tolerances, it may be necessary to undertake multiple drawing processes.
In this case, you employ successive dies with smaller apertures. In between the drawing processes, annealing aids in cold work removal and enhancing ductility.
Annealing is a heating process useful in reducing aluminum’s internal stresses, softening it, and/or changing the its mechanical and machining properties. The product’s final features determine when to employ annealing i.e. prior to, during, or after the drawing procedure.
Lubrication Methods when Wire Drawing Aluminum
Achieving an extended die service life and impressive surface finish is by undertaking lubrication during the drawing process. Some lubricating techniques include:
- Dry Drawing: Pass the aluminum stock through a lubricant pot containing lubricants that adhere to the surface.
- Metal Coating: Uses a soft metal derived from a solution such as copper sulfate as lubricant to coat the aluminum stock.
- Roll Drawing: Replace fixed dies with roller dies transforming shear friction to rolling friction with a significant decrease in drawing forces.
- Ultrasonic Vibration: Vibrate the mandrels and dies during every passage to help lower applied forces and enable bigger reductions.
- Wet Drawing: Entirely submerge the stock in baths containing lubricants such as oils.
Aluminum Wire Drawing Equipment
Some of the equipment you employ in wire drawing aluminum are:
Continuous Drawing Machines
These have several drawing dies interspaced with accumulating drums that are driven by motors to generate required pulling force. As the machine moves, the drums sustain a tension in the wire as it moves along the dies.
With each die comes a specific wire reduction allowing the series to accomplish the desired overall reduction. In between die sets, at times annealing is necessary to meet the desired reduction.
Diamond, tungsten carbide, or tool steel find common use in the construction of drawing dies as follows:
- Single Crystal Diamond Die: Wire drawing into very small diameters between 2 µm to 1.5 mm.
- Cast-Steel Die: When hot drawing because of their excellent level of wear resistance at high temperatures.
- Tungsten Carbide Die: Use as inserts with steel construction for support due to their extremely low hardness and tensile strength.
- Entry: Bell-shaped and does not interact with the aluminum workpiece. Channels lubricant and prevents scoring.
- Approach Angle: Ranging between 6 and 20 degrees, has a conical shape and is the location of the wire drawing procedure.
- Land: influences final reduction size.
- Back relief: Has a working angle of roughly 30 degrees with the workpiece exiting here.
It is necessary to cut the aluminium wire to a specific length after drawing. A variable frequency drive encompassing a line shaft powered electrically with a primary and follower drive is sufficient.
You can set up a wire barrel packer next to the wire drawer or in another location for coiling. Positioning the barrel on a turn table, a motor pair helps you recoil the wire to the barrel’s bottom.
Spoolers and Coilers
Spoolers are synonymous with terminations of drawing machines for aluminum wire. Their main function is to spool or wind the finished aluminum wire for shipping with reduced power output below 50 hp.
Alternately, coilers operate independently to coil aluminium wires of different mechanical properties and gauge. They can achieve high speed winding of heavy aluminium cables with power outputs reaching 1,000 hp.
Applications for Aluminum Wire Drawing
Some common applications of wire drawn aluminum are:
- The manufacture of electrical cables.
- Use as tension-loaded elements in structural engineering.
- Making paper clips and wheel spokes for motorbikes and vehicles.
- Manufacture of some stringed instruments.
Advantages of Wire Drawing Aluminum
There are several benefits you accrue in employing aluminum wire drawing such as:
- Achieve tighter dimensional control.
- Enhanced mechanical characteristics including rigidity and strength.
- Is cost effective for both small volumes and large volumes.
- Obtain impressive aluminum wire surface finishes.
Drawing Defects in Wire Drawing Aluminum
When wire drawing aluminum, you can encounter defects as seen in extrusion such as center cracking and seams. Others include:
i. Insufficient lubrication, bad die maintenance, and incorrect process parameter selection can result in surface flaws such as die imprints and scuffs.
ii. Residual stress resulting from the uneven deformation of the cold drawing procedure. While minimal in light reductions, heavy reductions encourage tensile stress on the surface ultimately resulting in cracking.
iii. Seams are scuffs or wrinkles along the y-plane of the material which manifest in the wake of secondary forming processes.
iv. Additionally, subsequently removal of surface material through grinding, slitting, or machining can induce warping.
If you consider every technique and advice, aluminum wire drawing will be simple and straight forward process.
For any questions or clarifications on aluminum wire drawing needs, contact us now.
Wire Drawing – Source: Wikipedia
Wire Drawing Process – Source: Britanica
What Is Wire Drawing – Source: About Mechanics