Wire Forming

Chapter One – What is Wire Forming?

Wire forming is a process that involves applying force to alter the shape of wire through techniques such as bending, swaging, piercing, chamfering, and shearing. These methods can produce a wide range of shapes, forms, or configurations. The process begins with coiled wire, which is first straightened before being shaped.

Common metals used in wire forming include steel, brass, stainless steel, copper, aluminum, and various alloys. Wire diameters range from 0.5 mm to 6.5 mm (1/64 inch to a quarter inch) and can be shaped into both two-dimensional and three-dimensional forms.

Wire forming equipment ranges from manual crafting tools to advanced CNC programmable machines. The process also includes options for coating and protecting the final products to ensure their durability in harsh conditions.

Chapter Two - Methods Used for Wire Forming

There are various types of equipment used for wire forming, generally falling into manual or automatic categories. Manual machines include those operated by hand and those that, while electronic, require manual loading. Automatic machines feature advanced computer numerically controlled (CNC) programming and perform the entire production process without manual intervention.

Drawing Method

Before wire forming can begin, the wire is drawn through a die to achieve the desired dimensions. The drawing tool is funnel-shaped, gradually pulling the wire through. As the wire passes through the die or multiple dies, the pressure exerted by the die sides reduces the wire's diameter while increasing its hardness and length.

The Drawing Process

1. Install the Drawplate: The drawplate has to be securely installed to offer the necessary leverage. Drawbenches specially drawbenches designed for the process are normally used.
2. Tapering: One to two inches (2.5-5 cm) of the wire has to be tapered before it can be inserted into the die.
3. Annealing: Annealing wire before putting it through the drawing process will prevent the wire from breaking during drawing. In most cases, after annealing, the wire is pickled to remove any oxidation.
4. Lubrication: There are several possible types of lubricants available that make the movement of the wire through the die smoother.
5. Pull Through: The tapered end of the wire is inserted into the unmarked side of the drawplate and slowly pulled through.

Methods Used to Form Wire

Wire forming employs various processes, each tailored to produce specific shapes, patterns, or configurations. While these methods are also used in other part production, they have been adapted specifically for wire forming.

Manual Wire Forming

The oldest method of wire forming involves manually operated machines, which use a hand lever and spindle. These manual machines can feature either draw or rotary dies and are equipped with gears that enhance the applied bending force.

Coil Wire Forming

Coil or spring wire forming involves winding wire around a metal blank. This method is also used to produce electrical coils, where conductive wire is evenly wound around a ferromagnetic core. The winding process varies depending on the final product. Electrical coils require more precise winding than springs and may involve multiple layers of winding.

Roll Wire Forming

Roll forming is a cost-effective method for producing flat, round, and various other shapes of wire parts. This process can create undercuts, knurls, points, chamfers, grooves, surface finishes, collars, and threads. Roll-formed wire parts gain additional strength after hardening and feature rounded edges and prefinished surfaces.

Bending Wire Forming

In the wire bending process, wire can be shaped into a wide variety of configurations to suit any application. Wire diameters ranging from 0.016 inches to 0.635 inches (0.4 mm to 16 mm) can be easily formed. Since the bends are made before the wire is cut, this process generates no scrap or waste and eliminates the need for secondary finishing.

Fourslide Wire Forming

Fourslide forming, or stamping, utilizes a horizontal stamping press equipped with additional cams. The machine includes shafts, an electric motor, a die, a press, and sliding tools. This process features four sliding tools that shape the wire from all sides. The cams control the movement of these tools, enabling both vertical actions, such as punching, and horizontal movements in multiple directions.

The fourslide process offers an alternative to traditional stamping by rapidly producing complex, smaller forms. Unlike conventional unidirectional stamping, it can shape metal strips from four directions simultaneously and efficiently.

Hydraulic Wire Forming

In a hydraulic wire forming machine, a hydraulic motor drives the shaping rollers. The machine is programmed with a servo motor and CNC technology to achieve the desired configuration. Once the operation is complete, the wire shapes are automatically ejected from the machine.

Pneumatic Wire Forming

In the pneumatic process, wire is fed into a straightening machine, shaped to the desired form, and then cut to the correct length using pneumatic mechanisms.

CNC Wire Bending

CNC wire bending machines can be pneumatic or hydraulic for efficient and rapid production. They can bend and shape rebar to 180o using single or double wire. The machine straightens the bar prior to the bending process.

Programmed CNC machines offer exceptional accuracy, cutting wire to precise dimensions. Although they are slower compared to other processes and do not require tooling, they are ideal for low-volume production or prototyping. CNC machines can be programmed to shape various types of wire, including music wire, hard-drawn, basic or coated metals, 300 series stainless steel, brass, and beryllium copper. The wire diameters range from 0.008 inches to 0.250 inches (0.0203 mm to 6.35 mm).

Wire Ends and Interior Geometries

Machine Cut End

Wire ends can be cut straight with minimal burrs or finished with a clean cut free of burrs. The wire can also be quill or angle cut, with a single angle or angles on both sides of the end.

Chamfered End

Chamfered ends have a smooth flat slope around the end to remove sharp edges.

Winging

Winging or swaging cut is accomplished by placing the end of the wire in a die that creates a wing shape on the end of the wire.

Pierced Swaging

In pierced swaging, the wire is first cut to create a swaged shape, and then a hole is punched in the center of the swaged area.

Custom Shaped Hole

For custom-shaped holes, the end of the wire is trimmed by a die, which then punctures the wire to create the desired hole shape.

Chisel Point and Turned End

In this process, dies form a jagged end by cutting the wire on a diagonal.

Ball End

A lathe shapes the end of the wire into the form of a ball.

Groove

As with the process of forming a ball end, in the groove end process, a groove is cut into the end of the wire.

Cold Heading

In cold heading, the wire is subjected to multiple blows to flatten or round the end, which can result in button, carriage, or collar headings.

Wire Forming Tolerances

Adhering to precise tolerances is crucial in all manufacturing processes, particularly in wire forming due to its critical applications. Wire forming tolerances typically are ±0.01 per bend or ±0.06 on an assembly. Achieving other tolerances may require specialized machining, tooling, alternative processes, and meticulous engineering, as illustrated in the chart below.

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Chapter Three - Types of Wire Forms

The range of wire shapes, configurations, and forms is virtually limitless, with new ones continually being developed. Wire forming can create anything from complex, intricate three-dimensional designs to simple hooks and springs. Many of the items we use daily incorporate some form of wire forming.

Types of Wire Forms

Hose Clamps

Wire hose clamps are made from heavy wire bent into a U shape and then formed into a ring with one end overlapping the other. The ends are bent upward to allow for opening. When the ends are pushed apart, the clamp tightens around the hose, applying even pressure to prevent leaks. To loosen the clamp, the ends are pushed together.

J Hook

There are many types of J hooks, with the fishhook being one of the most common. They can be coated to protect the materials they hold and often feature notches for hanging. Double J hooks, when attached to a strap, are capable of supporting substantial loads.

Linchpins

Linchpins are inserted into the end of an axle to prevent wheels from coming off. They are made from aluminum, zinc, brass, and stainless steel.

R Clips

R-clips, also known by various names, are metal wire fasteners shaped like the letter R. They function similarly to linchpins, securing the end of an axle or rod with a wheel. The long, straight portion of the clip fits through a hole at the end of the shaft, while the springy part loops over the shaft at the top or bottom. The semi-circular, bent section of the clip fits snugly around the shaft. To facilitate insertion into the shaft's hole, the end of the semi-circular part is bent upward, as shown in the image below.

S Hook

Both ends of an S hook are bent to form the S shape. They are normally used for hanging storage or for organizing cables, hoses, and cords as a safety measure.

Springs

Among the various wire forms, springs are the most common and widely utilized. They consist of a coil wound into a tightly wrapped spiral to achieve specific tension requirements. The type of spring chosen depends on its intended use and application.

Threaded Wire Forms

In the wire form threading process, a metal rod is passed through a set of threading dies that shape the threads with peaks and valleys. This method produces high-strength threads quickly. Unlike rolled threading, which forms threads by rolling the metal, cut threading removes metal from the workpiece to create the threads. This method allows for a wider range of diameters, thread lengths, and pitch combinations.

Utility Hook

Utility hooks feature a threaded end and a hook, making installation straightforward. The manufacturing process involves several bends, including offset bends on both sides of the loop and a final bend at the end of the loop that touches the opposite side.

Wire Baskets

Wire Baskets are used for bulk storage of parts, equipment, and components. They are made of a welded wire mesh. Some forms have a rust-resistant electrogalvanized finish to prevent wear and rusting. The open mesh design provides excellent strength, inventory control, visibility, and forklift access. In production facilities, they can be used to strategically place parts for easy access.

Wire Displays

Wire displays are a durable and cost-effective solution for showcasing products. They are manufactured by bending, shaping, and forming wire made from low, medium, or high carbon steel, as well as from stainless steel, copper, and aluminum brass. After the wire is formed, it can be coated, plated, or painted to enhance its appearance and durability.

Wire Guards

Wire guards come in various forms, all designed to prevent access to equipment, passageways, instruments, and sensitive materials. Hinged wire guards, or wire cages, are used to protect sensitive equipment in high-traffic areas, such as manufacturing locations and athletic fields, from potential damage. Open-face wire guards prevent accidental activation of fire alarms or emergency stop switches. Additionally, they are used to enclose automated and robotic machinery, tanks, heavy equipment, motors, and spiral HVAC fans, ensuring safety and security.

Wire Screens

Wire screens Thin metal wires are woven horizontally and vertically to create an open protective barrier that limits access and material flow. These intersecting wires are either welded or woven. The wire is shaped to the appropriate diameter using various wire-forming processes. In the welding process, a preprogrammed machine welds the rows and columns together at their intersections. In the woven wire screen process, the wires are woven in a manner similar to cloth, passing over and under each other at perpendicular intersections.

Z Clip

Z clips are utilized to securely lock components in place. The extended portion of the Z clip slips over the item to be secured and is anchored at both ends to ensure a firm hold. They are available in various thicknesses and diameters to suit different applications. Very small Z clips are used to hold electronic computer components. The advantages of Z clips include their strength, versatility, and resistance to corrosion.

Chapter Four – What Are The Wire Forming Materials

Wire forms can be fabricated from a wide variety of metals, including aluminum, copper, steel, brass, stainless steel grades 304, 316, and 434, as well as various types of alloys.

Bright Basic Wire

Bright basic wire (BBW) is a low carbon steel wire with a bright polished finish. It is cold drawn to enhance its tensile strength and mechanical properties. BBW possesses the essential physical properties for bending, straightening, welding, and finishing with epoxy, plastic, galvanization, or powder coating. The common grades of BBW used for wire forming are 1008C and 1018C.

Galvanized Wire

Galvanized wire is carbon steel wire coated with zinc through electroplating or hot-dipping. This process makes it rust-resistant and exceptionally strong, and it is available in various gauges. In the hot-dipping process, the carbon steel wire is submerged in a zinc bath. Upon removal, the wire cools and reacts with the surrounding oxygen, binding the zinc to the carbon steel.

Stainless Steel 304

Stainless steel grade 304 has high resistance to corrosion with a tensile strength of 621 MPa and can be used in conditions with mild corrosive elements or where handling of heavy loads is required. The quality of grade 304 makes it durable and long-lasting. It can be used in conditions that have temperatures that exceed 1500° F (815.5° C) less than 2500° F (1371 ° C). It may be important for some applications that none of the 300 grade stainless steels are magnetic.

Stainless Steel 316

Grade 316 stainless steel is more resistant to corrosion and can withstand the effects of chlorides. It has a tensile strength of 579 MPa and can handle extremely heavy loads. Grade 316 can be used in environments with temperatures that do not exceed 1400° F (760 ° C). Its ability to withstand caustic or highly corrosive environments has made it extremely useful.

Stainless Steel 434

Stainless steel grade 434 is a ferritic alloy that is resistant to pitting and does not have any nickel content, which makes it less expensive. A restriction on stainless steel grade 434 is the temperatures at which it can be used, less than 1500° F (815.5° C), limiting its use for heat treatment applications. It is highly resistant to oxidation, corrosion, and pitting and is very useful in the production of industrial baskets.

Brass Wire

Brass is an alloy consisting of 67% copper and 33% zinc, retaining the electrical and heat conductivity and malleability of copper. It is stronger than copper, making it suitable for a wider range of applications, including wire forming. Certain brass alloys include elements like antimony, arsenic, iron, and tin to enhance mechanical and physical properties such as hardness, formability, strength, and appearance.

Copper Wire

Copper (Cu) is a soft, malleable, and ductile metal with high electrical and thermal conductivity and a reddish-orange hue. Its excellent conductivity and ease of shaping make it ideal for wire forming. Copper is resistant to rust and corrosion, and over time, it develops a green patina when exposed to the atmosphere.

Aluminum Wire

Aluminum (Al) is a soft, non-magnetic, and ductile metal, making it the third most abundant metal on Earth. It is derived from bauxite and often occurs in combination with over 270 other minerals. Aluminum is known for its low density and resistance to corrosion. For wire forming applications, aluminum is alloyed with other metals because it is prone to deformation in its pure form. Key alloying metals include copper, zinc, magnesium, manganese, and silicon.

Steel Wire

Steel is an alloy of iron with added carbon to enhance its strength and resistance to fracturing. Its primary appeal in manufacturing lies in its high tensile strength combined with affordability. The base metal of steel is iron, and the interaction between iron's allotropes and its alloying elements, primarily carbon, imparts the steel's properties. Since pure iron is soft and ductile, the addition of carbon and other alloys increases its hardness, strength, and durability.

Chapter Five – How Are Wire Forms Used?

Wire forming is a key process in industries that utilize wire to create components and parts. This technique encompasses both standard shapes and custom-designed forms, making it highly adaptable to various conditions, materials, and engineering requirements.

Uses for Wire Formed Parts

Medical Uses

Parts for the medical industry must be durable, smooth, and exceptionally clean. Stainless steel is the primary metal used for manufacturing medical components because it can endure high temperatures, repeated cleanings, and sterilization. Its smooth surface helps prevent nicks, cuts, and punctures to medical workers' gloves and garments.

Industrial Uses

Industrial operations demand fast and precise methods for assembly and manufacturing. Wire-formed baskets play a crucial role in the efficient and organized delivery of parts to production areas, ensuring convenience and speed in handling.

Automotive Uses

In the automotive industry, wire forming encompasses a range of components including wire springs, compression coils, and volute springs for suspension systems. Delicate springs, such as torsion and tension springs, serve various functions, including supporting swing-down tailgates. Additionally, conical springs are used in manufacturing battery contacts.

Athletic Uses

Masks used in contact sports are wire-formed for protection and are designed to meet the standards set by the National Operating Committee on Standards for Athletic Equipment (NOCSAE).

Telecommunications Uses

Steel wire is utilized for guides and trays due to its smooth surface. The open design facilitates easy access for cable installation, inspection, and upgrades. Routing rings can be attached to frames to manage various types of wire, thanks to the strength of the wire frame. Trays, troughs, and support hardware are designed for efficient cable management, incorporating routing rings and tie bars for optimal organization.

Retail Uses

A common use of wire forming in retail is product display racks that are lightweight but sturdy enough to hold products for customer inspection. They can be placed at cash registers as point of purchase displays or in multiple locations throughout the store. Their light weight makes it easy to relocate them to high-traffic aisles. Wire racks are also a convenient way for storing merchandise for future sales and conducting inventory.

Food Uses

The food industry must adhere to numerous regulations to comply with FDA requirements and specifications. Wire storage and processing racks must meet stringent standards for sanitation and cleanliness. They are constructed from high-grade stainless steel, which is corrosion- and rust-resistant, and capable of being continuously sanitized and washed.

Construction Uses

Wire forms play a crucial role in building construction, serving various functions such as holding wires, supporting hooks, springs, pins, wire guards, equipment frames, and wire screens. They are used not only as essential construction materials but also in decorative applications, including guardrails and accent pieces.

Chapter Six – What Are The Wire Forming Process Details

The wire forming process involves four key steps that should be considered when deciding to wire-form a part or component. These steps include selecting the appropriate type of wire for the application, straightening the wire before processing, applying force to shape the design, and determining if secondary processing is required.

Wire Form Process

Wire Selection

The gauge, diameter, and type of wire used in the wire forming process are determined by the initial CAD design. Steel and stainless steel are commonly used for applications requiring durable and long-lasting components, while lightweight wires like aluminum and copper are suitable for less demanding conditions. Wire can be made from low, medium, and high carbon steel, as well as stainless steel, aluminum, copper, brass, and various alloys.

Wire Straightening

Wire is stored in coils and must be straightened before processing. This step removes stress deformities that may have developed during storage. Machine rolling is used for straightening the wire. Uncontrolled irregularities in this process can result in poor wire form.

Applying Force

Wire forming involves applying force to alter the contour and shape of the wire into the desired form. This shaping process is designed to create a diverse range of shapes and configurations. Force can be applied manually or using various automated equipment, including dies and cutting tools. For high-volume production, CNC machines and four-slide machines are commonly used.

Finishing Wire Exterior

The need for finishing in wire forming depends on the type of product and its design. While some wire-formed products may not require additional finishing, others might need post-production adjustments such as cuts, grooves, heading, coining, or swaging. The primary focus of finishing is to ensure that burrs and sharp edges are smoothed out and removed.

Conclusion

• Wire forming is a process for adjusting the contour of straightened wire to achieve a unique shape or design.
• The wire forming process uses several different metals including stainless steel, steel, aluminum, copper, brass, and alloyed metals.
• Wire forming is used by several manufacturing operations that include automobile production, medical equipment, food production, and shipping and handling.
• The types of equipment to complete wire forming vary between manual crafting to advanced CNC programmable machines.
• There is an endless variety of wire forms, which increases regularly as new uses and applications are developed.

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