Cold Heading (Cold Forging, Cold Forming)

Cold heading

Cold heading (Cold forging, Cold forming), a core technology of FINECS Group, is a metal working method in which a metallic material is shaped through the application of the appropriate force. The "cold" in cold heading means that the working process attains the intended shape at ordinary temperatures only through impacting, stretching, bending and/or other force applications, without heating the material for deformation.
At FINECS, we produce all tooling by ourselves, enabling us to offer higher precision at smaller tolerances compared to ordinary processes. Furthermore, we developed our technology to manufacture with nearly no occurrence of burrs.
The primary advantage of cold heading compared to machining and other shaping methods involving material-removal is high volume production at high speed.
Among various other cold heading processes, we at FINECS specialize in heading from wire or rod materials and we offer a variety of components for consumer products, automotive parts, and medical equipment.

Methods for Cold Heading and other processing

Comparison to Stamping

• ・No stamping out of material = no loss of material.
• ・Tooling costs are cheaper.

Comparison to Cutting

• ・Production without cutting = no occurrence of cutting scraps
• ・Quick high volume manufacturing possible

Comparison of press-working / cutting / cold-heading

Pin and terminal processing by cold-heading, which is processed from metal wire, can reduce costs compared to press-working and cutting.
we presented a comparison table of each processing method. It is important to select the processing method for each application.
When considering the procurement of pins and terminals, please consider using cold-heading.

	Press-working	Cold-heading	Cutting
Initial costs	✕ A few million JPY.	〇 A few hundreds of thousands JPY.	None
Mold maintenance costs	✕ Lots of maintenance parts.	〇 Fewer maintenance parts.	None
Material loss	△	〇	✕ Quite a lot.
Mass production unit price	〇	〇	✕ Very expensive.
Productivity	〇	〇 Can produce more than 1 million pieces / month.	✕ Low production utilization rate.
Exposure of base material when using pre-plated material	✕ Eexposed pullout surface.	〇 Only tip.	✕ Unavailable.
Tip shape	2 side R	4 side R Can be changed R angle and dimensions.	2 side R / 4 side R
Other features	For change the terminal pitch and total length is required new mold production. Round pin processing is impossible.	Easy to process round pins. Bandolier→Supports pitch changes Changing the total length of the terminal is only adjustment, Does not require new mold production.	Only can processing Round pin.
Also known as	Stamping	Cold-forging Cold-forming

Heading and Forging

In metal working at ordinary temperatures (cold metal working), the terms "forging" and "heading" have the same basic meaning. When working metal by applying pressure to mold the material to the desired shape, the word "forging" is often used to refer to increasing mechanical strength while also achieving the desired shape through deformation, as the term "forging" is traditionally used. “Heading,” which is a similar metalworking process using high pressure, is called heading (forming) processing, and it is primarily used to create shapes similar to screw heads.
As you can see, both terms are nearly identical in their meaning, but a common way to separate these two is the direction of the pressure added to the material: During Heading pressure is applied horizontally to shape the material, while during Forging this pressure comes in vertically.

Cold Heading/Forging and Hot Heading/Forging

Heading and Forging are classified according to the temperature of the material at the time of processing.
While Cold Heading (Forging) is done at room temperature, there also exist the methods of Warm or Hot Heading where heat is applied to the material before the actual processing.
As all these methods hold advantages and disadvantages over each other, the right choice of method should be made depending on the desired application of the product.

Cold Heading (Cold Forging)

• ・Advantages: high precision, high speed, smooth surface
• ・Disadvantage: Complex shapes are difficult

Hot Heading (Hot Forging)

• ・Advantage: Complex shapes are possible
• ・Disadvantages: Less precise, slow processing, rough surface

Warm Heading (Warm Forging)

As the temperature lies in between the other two methods, so do its advantages and disadvantages

At FINECS, we make only Cold heading product.

Heading and Rolling

The rolling process is also referred to as rotary forging. During this process the material gets deformed by applying pressure while rotating the material. Normally, the head part of a bolt is made by Heading and the thread part by rolling.

At FINECS, we make only Cold heading product.

Materials for headed parts

This section describes the major classes of metals used in cold heading.

Copper (Cu)-based metal alloys

Copper (Cu) ranks second among pure metals in electrical conductivity at room temperature (silver (Ag) is first, followed by Cu and gold (Au)). It is available at relatively low prices compared to other electrically conductive metals and so it sees widespread use in heading processes for the manufacturing of electrical contact terminals.
In order to enhance the basic properties of Cu mentioned above for specific application uses, a variety of Cu-based alloys are used in the heading process.

Pure copper

Pure copper does not contain any additional alloying element, thus demonstrating the high electrical conductivity specific to Cu, although it is inferior to other copper alloys in strength.
The pure copper varieties used in heading processes includes electrolytic tough-pitch copper (C1100), which retains 0.02-0.05% oxygen content to detoxify any impurities which could interfere with conductivity, and oxygen-free copper (C1020), refined to remove as much oxygen contamination as possible to avoid hydrogen embrittlement, a disadvantage of electrolytic tough-pitch copper.

Brass

Brass is an alloy of copper (Cu) and zinc (Zn). As the Zn content increases, it becomes harder but also more brittle. It offers good processability for a variety of heading process needs with adjustment to the alloying agent ratios. Consequently, brass is used not only for electrical parts but also large-sized auto parts and headed parts for building construction.
Primarily C2600 (70% Cu and 30% Zn) and C2700 (65% Cu and 35% Zn) are put into wide use.

Phosphor bronze

This alloy of copper (Cu), tin (Sn) and small amounts of phosphorus (P) constitutes a type of bronze. It features high mechanical strength and spring characteristics. It is also excellent in wear resistance and is non-magnetic, thus finding wide application in springs, switches, gears and other headed parts for various types of electronic equipment.

Other Cu alloys

Other alloys like Corson are also attracting attention due to their springiness and higher electrical conductivity.

Ferrous metals

Stainless steel

Stainless steel is a steel alloy with a minimum of 10.5% chromium content by mass added to the principal component Fe to ensure that it does not readily corrode. The chromium content binds with oxygen in the air, creating a protective passivation layer on the surface and thus ensuring higher corrosion resistance.

Other metals

Aluminum

Aluminum is lightweight, approximately 35% less relative density than iron, and excellent in thermal conductivity, electrical conductivity, and ease of processing. It creates a protective film of oxide in the air and as a result provides higher resistance to corrosion. Pure aluminum offers low strength and so aluminum is often used in the form of aluminum alloys. Aluminum sees widespread use in rivets and other headed parts.

Precious metals

Precious metals like gold (Au) or silver (Ag) are often used as brazing material.

Methods for processing headed parts

In the cold heading process, headed parts are manufactured with a combination of "punches" to cause deformation by applying force directly to the material in question and "dies" to hold the material.
Punches and dies are available in various designs for different forms of materials and final intended shapes. They are combined to accommodate a wide variety of heading work, as listed below.

Upsetting

Upsetting refers to a heading process of hitting a material held in dies with a punch in the longitudinal direction to reduce the length of the material while increasing the diameter correspondingly.
It is used in processing the head section of rivets, bolts and other headed parts.

Forward extrusion

Material is placed on a die that is narrower than the material’s original diameter, and is then hit with a punch to drive it through the die and reduce its diameter while correspondingly increasing the material’s length.

Backward extrusion

A material held in dies is hit with a punch having a smaller diameter than the dies and material. The material flows into the space between the dies and punch, forming a cup-like shape.
This is used in the making of blind-rivet shanks, for example.