Chapter One – What is Wire Forming?
Wire forming is a method for applying force to change the contour of wire by bending, swaging, piercing, chamfering, shearing, or other techniques. The various techniques for wire forming can produce any type of shape, form, or configuration. The process starts with coiled wire that is straightened before being formed.
Common metals used for wire forming include steel, brass, stainless steel, copper, aluminum, and a variety of different alloys. The diameters of wires vary from 0.5 mm to 6.5 mm, or 1/64th of an inch to a quarter inch and can produce 2 and 3 dimensional wire forms.
The types of equipment to complete wire forming vary between manual crafting to advanced CNC programmable machines. The process includes options for coating and protecting final products for use in harsh conditions.
Chapter Two - Methods Used for Wire Forming
Though there are several types of equipment used to perform wire forming, in most cases, wire forming machines are manually or automatically operated. Manual machines include ones that are operated by manual force and ones that are electronic but manually loaded. Automatic machines have advanced computer numerically controlled (CNC) programming and complete production without manual involvement.
Methods For Wire Forming
Wire forming is performed using several different processes each designed to achieve a different shape, pattern, or configuration. The methods of wire forming are used for other part production but have been adjusted for wire forming.
Manual Wire Forming:
The oldest method for wire forming is manually operated machines, which involves a hand lever and spindle. Manual machines can be drawn or rotary die and have gears that increase the applied bending force.
Coil Wire Forming:
Coil, or spring wire forming, involves winding wire around a metal blank. It is also used for the manufacture of electrical coils where a conductive wire is evenly wound around a ferromagnetic core. Coil winding takes different forms depending on the final product. Electrical coils have to be more precisely wound than springs and can require more than one winding.
Roll Wire Forming:
Roll forming is a cost efficient method for the production of flat, round, and other shapes of wire parts. The process can manufacture undercuts, knurls, pointing, chamfers, grooves, surface finishes, collars, and threads. Roll formed wire parts have extra strength after being hardened, having rounded edges, and being prefinishing.
Bend Wire Forming:
In the wire bending process, wire can be shaped into unlimited configurations to fit any application. Diameters of 0.4 mm to 16 mm, or 0.016 in to 0.625 in, can be easily formed. Since the bend in the wire is made prior to the wire being cut, the process has no scrap or waste and does not need secondary finishing.
Fourslide Wire Forming:
Fourslide forming or stamping uses the same process as a horizontal stamping press with the addition of cams. Along with the cams, the machine has shafts, an electric motor, a die, a press, and sliding tools. The process has four sliding tools that form the wire from four sides. The cam regulates the movement of the four tools, which allows the process to have vertical movement, such as punching, with horizontal movement in several directions.
Hydraulic Wire Forming:
In a hydraulic wire forming machine, a hydraulic motor is used to drive the shaping rollers. A servo motor and CNC programming program the machine to the required configuration. Wire shapes are automatically discharged from the machine after the completion of the operation.
Pneumatic Wire Forming:
In the pneumatic process, wire is fed into the straightening machine, formed to the required shape, and pneumatically cut to the proper length. The process is explained in the video below from NOVO Precision.
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. CNC machines have exceptional accuracy and cut wire to the exact required dimensions. The types of wire a CNC machine can be programmed to shape includes music, hard drawn, basic or coated metals, 300 series stainless steel, brass, and beryllium copper. Wire diameters vary between 0.008 in to 0.250 in or 0.0203 mm to 6.35 mm.
Wire Ends and Interior Geometries
Machine Cut End:
Wire ends can be cut straight with miniscule burrs or be clean cut without burrs. The finished wire can be quill or angle cut with a single angle or an angle 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:
With pierced swaging, the wire is cut to give it a swaging shape and a hole is cut in the center of the swaging.
Custom Shaped Hole:
With custom shaped holes, a hole is cut in the end of the wire after the wire has been trimmed by a die that punctures the wire to form the hole.
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 in 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.
Chapter Three - Types of Wire Forms
The number of wire shapes, configurations, and forms is endless since new ones are constantly being developed. Wire forming can produce any shape imaginable from complex intricate 3 dimensional designs to simple hooks and springs. Many of the things we use have involved some form of wire forming.
Types of Wire Forms
Springs:
Of all the types of wire forms, springs are the most common and widely used. They are a coil that has been wound into a tightly wrapped spiral to meet preset tension requirements. The type of spring depends on how it will be used and its application.
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.
Utility Hook:
Utility hooks have a threaded end and hook, which allows for easy installation. A utility hook requires multiple bends during the manufacturing process including an offset bend to both sides of the loop with a bend at the end of the loop that touches the other side.
S Hook:
Both ends of a 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.
J Hook:
There are many varieties of J hooks with the most common being the fishhook. They can be coated for protection of materials placed on them and have notches so they can be hung. Double J hooks are capable of holding huge loads when attached to a strap.
Wire Displays:
Wire displays are a durable and inexpensive means for displaying products. They are produced by bending, shaping, and forming wire made of low, medium, or high carbon steel but can also be made of stainless steel, copper, and aluminum brass. Once they are wire formed, they can be coated, plated, or painted.
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 Screens:
Wire screens have thin metal woven wires that are crisscrossed horizontally and vertically to form an open protective barrier to limit access and material flow. The intersecting wires are welded or woven. The wire used in the process is shaped by one of the various wire forming processes to the appropriate diameter. With the welding process, the rows and columns are welded together at their intersection by a preprogrammed machine. With woven wire screen, the process is similar to woven cloth where the wire goes over and under at perpendicular intersections.
Wire Guards:
There are many forms of wire guards that are 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 from the activities associated with manufacturing locations and athletic fields. Open face wire guards prevent activation of fire alarms or emergency stop switches. They are used to enclose automated and robotic machinery, tanks, heavy equipment, motors and spiral HVAC fans.
Z Clip:
Z clips are used to lock components in place. The long portion of the Z clip slips over the item to be held and is anchored at both ends to form a secure hold. They come in a wide range of thicknesses and diameters depending on how they are used. Very small Z clips are used to hold electronic computer components. The benefits of Z clips are their strength, versatility, and resistance to corrosion.
Threaded Wire Forms:
In the wire form threading process, a metal rod is rolled through a set of threading dies that create the peaks and valleys of the threads. The process produces threads with high strength in fast cycle times. Unlike the rolled threading process, cut threading removes metal from the workpiece to create the threads and can be used with a wider range of diameters, thread lengths, and pitch combinations.
Hose Clamps:
Wire hose clamps use heavy wire that is bent into a U shape, which is formed into a ring with one end of the wire overlapping the other end. The two ends are bent upward so they can be opened. When the bent ends are pushed apart, they tighten around the hose and provide equal pressure to seal off the hose from leaks. To loosen the clamp, the bent ends are pushed together.
R Clips:
R-clips, which are known by a wide variety of names, are fasteners made of metal wire and have the shape of the letter R. They have a similar use to that of a linchpin and are used to secure 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 goes over the shaft at the top or bottom. The semi-circular, bent part, fits snuggly on the shaft. To ease insertion of the pin into the hole on the shaft, the end of the semi-circular part is bent upward, as seen in the image below.
Chapter Four – Wire Forming Materials
The fabrication of wire forms can be completed using a wide variety of metals that include aluminum, copper, steel, brass, stainless steel grades 304, 316, and 434, and various types of alloys.
Wire Forming Materials
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 1500o F but less than 2500o F.
Stainless Steel 316:
Grade 316 stainless steel has higher resistance to corrosion and can withstand the effects of chlorides. It has a tensile strength of 579 MPa and can handle extreme heavy loads. Grade 316 can be used in environments with temperatures that do not exceed 1400o F. 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 are the temperatures at which it can be used, less than 1500o F, 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:
Brass is an alloy composed of 67% copper and 33% zinc with the characteristics of copper including its electrical and heat conductivity as well as its malleability. Since it is stronger than copper, it is used in a wider variety of applications, which include wire forming. Some forms of brass have antimony, arsenic, iron, and tin, which are added to improve its mechanical and physical properties, such as hardness, formability, strength or appearance.
Copper:
Copper (Cu) is a soft, malleable, and ductile metal that has high electrical and heat conductivity with a reddish orange tint. Its ability to be easily shaped and formed makes it ideal metal for wire forming. Copper is resistant to rust and corrosion with a surface that forms a green layer when exposed to the atmosphere over a long period of time.
Aluminum:
Aluminum (Al) is a soft, non-magnetic, ductile metal and is the third most abundant metal on Earth. It is processed from bauxite and is found combined with over 270 other minerals. The main attributes of aluminum are its low density and corrosion resistance. To be used in the manufacture of wire forms, it has to be alloyed with other metals since in its natural processed state it is subject to deformation. The main alloying metals are copper, zinc, magnesium, manganese, and silicon.
Steel:
Steel is an alloy of iron with carbon added to improve its strength and resistance to fracturing. The main reason that steel is used in manufacturing is its tensile strength combined with low cost. The base metal of steel is iron. The interaction of the allotropes of iron with its alloys, mainly carbon, gives steel its properties. Since pure iron is very soft and ductile, the addition of carbon and other alloys improves its hardness, strength, and durability.
Chapter Five – How Are Wire Forms Used
Wire forming is part of industries that use wire to produce their components and parts. Since wire forming includes standard common shapes and special designed forms, it is adaptable to any conditions, materials, or engineering needs.
Uses for Wire Formed Parts
Medical:
Parts for the medical industry have to be durable, smooth, and exceptionally clean. The main metal used for the manufacture of medical components is stainless steel since it can withstand high temperatures and multiple cleanings as well as sterilization. The smooth surface of stainless steel protects against nicks, cuts, and punctures to medical workers gloves and garments.
Industrial:
Industrial operations require quick efficient precision methods for performing assembly and manufacturing procedures. Wire formed baskets are important for the rapid delivery of parts to production in an organized and convenient way.
Automotive:
Wire forming in the automotive industry includes various types of wire springs, as well as compression coils and volute springs for suspension applications. Delicate springs, like torsion and tension springs, have multiple purposes, such as swing down tailgates. Conical springs are used in the production of battery contacts.
Sports:
Masks are wire formed as a protection for contact sports and are made to comply with the National Operating Committee Standards for Athletic Equipment (NOCSAE).
Telecommunications:
Steel wire is used for guides and trays because of its smooth surface. The open design allows for ease of access to cable installation, inspection, and upgrades. Routing rings can be attached to frames to handle any form of wire due to the strength of the wire frame. Trays, troughs, and support hardware are made for easy cable management with routing rings and tie bars.
Retail:
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 sale and conducting inventory.
Food:
The food industry has several regulations it must meet to be in compliance with FDA requirements and specifications. Wire storage and processing racks have to meet the standards for sanitary conditions and cleanliness. They are made from high grade stainless steel that is corrosion and rust resistant as well as being able to be constantly sanitized and washed.
Construction:
Wire forms are an important component in the construction of buildings for holding wires, support hooks, springs and pins, wire guards, equipment wire frames, and wire screens. They serve as construction materials and are part of decorative guardrails and accent pieces.
Chapter Six – Wire Forming Process Details
There are four basic steps to the wire forming process that have to be considered when making the decision for having a part or component wire formed. They include the selection of the proper type of wire for the application, straightening the wire before it is processed, the application of force to create the design configuration, and the need for secondary processing.
Wire Form Process
Wire Selection:
The gauge, diameter, and type of wire for the wire forming process is determined by the initial CAD design. Steel and stainless steel are the most common types of wire for applications that require resilient and long lasting components. Lightweight wires, such as aluminum and copper, are used for less demanding conditions. Wire can be made of low, medium, and high carbon steel, as well as stainless steel, aluminum, copper, brass, and various alloyed metals.
Wire Straightening:
Wire is stored in coils and has to be straightened before processing. During the straightening, stress deformities accumulated in storage have to be removed. Machine rolling is used to straighten wire. Uncontrolled irregularities can lead to a poor wire form. The video below, from Better Wire and Press, is an example of wire straightening and cutting to lengths.
Applying Force:
Wire forming requires the application of force to change the contour and shape of the wire into the desired form. The shaping process is designed to produce a wide array of shapes and configurations. Force is applied by hand or various automated equipment with dies and cutting tools. CNC and four slide machines are used for high volume production.
Finishing:
The need for finishing depends on the type of product. Wire forming may not require finishing depending on the design of the product. There are cases where cuts, grooves, heading, coining, swaging, and other after production adjustments have to be made. The most important function is ensuring that burrs and sharp edges are adjusted 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 that include 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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