A Guide to Understanding the Cold Heading Process

Cold heading is a high-speed metal forming process that shapes parts at room temperature without the need for heat. This innovative method is used to create stronger, more precise components, reducing waste and costs. 

Let’s take a closer look at the process itself and explore what makes it unique. 

What is Cold Heading?

Cold heading manufacturing is a multi-step cold forming process (also known as cold forging) used to form metal parts at room temperature. Unlike other metal fabrication processes, hammers and dies are used at a high speed to form the metal without heating the material.

Just as the name implies, cold heading is primarily used for forming the heads on fasteners like bolts, screws, rivets, and nails. 

Its true value lies in the many advantages it brings to manufacturing. Let’s dive into the key benefits that make cold heading a preferred choice for industries worldwide.

Advantages of Cold heading

Since the volume of the blank is hammered into a die without any cutting, cold heading produces minimal to no scrap material, reducing raw material waste compared to other processes, such as screw machining. In fact, screw machining can result in material scrap rates exceeding 70 percent. 

In addition, because no heat is required, there is less environmental impact, and workers are provided with a safer environment. The production is fast with no cooling down process required and creates pieces with closer tolerances without secondary operations like machining. Additional advantages of cold heading include:

• Less Waste: Cold heading maximizes material usage by reshaping the metal rather than cutting it, resulting in minimal scrap. This makes the process highly efficient in conserving raw materials.
• Faster Production: The cold heading process eliminates the need for heat and cooling times, allowing components to be produced rapidly and at high volumes, which accelerates overall production timelines.
• Stronger Parts: Cold heading strengthens parts by aligning the grain structure of the metal during forming, enhancing durability and resistance to wear and tear. In cold forming, metal is “work hardened”, increasing its tensile strength compared to pieces that have been cut, welded, or heat treated.
• Reduced Costs: By minimizing material waste and speeding up production, cold heading helps reduce overall production costs, making it a financially appealing manufacturing method.
• Cost-Effective: With its efficient use of materials, faster production, and reduced need for secondary processes, cold heading proves to be a cost-effective solution for high-volume manufacturing.

Simplifies Multi-Piece Assemblies

Cold heading offers incredible flexibility in part design so that a single cold headed part can take the place of multi-piece assemblies by reducing  the need for welding and assembly, dramatically cutting production time and costs.

Improves Precision and Reducing Secondary Operations

Many metal manufacturing methods require secondary operations, such as machining or grinding, to achieve dimensional accuracy and specifications. With cold heading, the result is near net-shape parts that deliver a high rate of precision.

In large volume production, the cost savings from eliminating these extra steps can be significant. Overall, cold headed manufacturing offers faster turnaround times, reduced costs, and produces more precise components. 

Maximizes Cost Savings and Efficiency Gains

In addition to reducing labor costs by eliminating extra steps, cold heading uses less material and reduces waste to achieve even greater efficiency. Since parts are formed into near net-shape, there is almost no scrap. With fewer finishing steps, rapid output can be achieved and the combination of reduced material waste, faster production cycles, and reduced labor costs leads to a streamlined manufacturing process and maximum cost savings.

Supports Sustainable Manufacturing

Compared to traditional metalworking processes, cold heading increases production with less environmental impact. Because cold heading is more efficient, less energy is consumed, and since near net-shape components are manufactured using this method, fewer raw materials are used. With lowered emissions and a reduced carbon footprint, cold heading is more eco-friendly, making it a top choice for manufacturers with sustainability goals. 

Disadvantages of Cold Heading

While cold heading offers numerous benefits, it’s not without its limitations. Here are some challenges manufacturers face when using this process.

Without heat, the pieces must be created with more force. While dies may be cheaper, the machinery required is bigger and more expensive. The pieces cannot be as thick as they may in machining because hammers can only force so much metal into a given space.

Harder metals can require multiple blows to fill a die and certain materials cannot be used in a cold heading machine at all. More complex pieces will require secondary operations as cold heading machines cannot perform operations like rolling, stamping, or bending.

Now that we’ve discussed the advantages and limitations of cold heading, let’s break down the detailed steps involved in the process, from material selection to final quality checks.

The Cold Heading Process

Here is an overview of the manufacturing process:

1. Material Selection: Choose the appropriate material for the cold heading process. Common materials include steel, stainless steel, aluminum, brass, and copper.
2. Die Design: Design dies that represent the final shape of the cold-headed part. Dies are typically made from tool steel and must withstand high pressure and repetitive impacts.
3. Die Making: Manufacture the dies based on the designed specifications. Precision CNC machining is crucial to ensure the accuracy of the final die .
4. Billet Preparation: Cut metal blanks, known as billets, from a larger piece of material. The billet size is determined based on the final part specifications.
5. Feeding Mechanism: Implement a feeding mechanism to accurately position the billet in the heading machine. This ensures proper alignment before the cold heading process begins.
6. Heading Machine Setup: Set up the cold heading machine with the required dies and tooling. Adjust the machine settings for factors such as pressure, feed rate, and stroke length.
7. Cold Heading Process: The machine applies pressure to the billet, forcing it into the dies. The metal is deformed and takes the shape of the dies. This is a cold forming process, meaning it occurs at room temperature without the need for additional heat.
8. Trimming and Piercing: Afterwards, excess material (flash) may be present. Trimming and piercing operations remove this excess material, resulting in the final shape of the part.
9. Quality Control: Inspect the cold-headed parts for dimensional accuracy and quality. Use measuring tools and visual inspection to ensure that the parts meet specifications. There are also sensors, cameras, and AI software that is specifically designed to inspect parts as they are being produced.
10. Finishing Operations: Additional operations such as thread rolling, surface coating, heat treating, or secondary CNC machining may be performed depending on the specific requirements of the part.
11. Tool Maintenance: Regularly inspect and maintain the dies and other tooling components to ensure continued accuracy and performance.

With a clear understanding of the cold heading process, let’s now explore the specific techniques used to shape metal in this method. Cold heading includes two main categories: upsetting and extrusion.

Cold Heading Techniques

There are 2 main categories of the cold heading process which are essentially 2 different techniques for forcing the material into the die. These 2 categories are cold heading upsetting and cold heading extrusion. With the upset method, the punch block forces the metal out of the die to produce a head larger than the initial blank.

Cold heading extrusion has 2 subprocesses which are forward extrusion and reverse extrusion. In addition, there are two types of forward extrusion which are open extrusion and trapped extrusion. We will outline the process of each of these below.

Cold Heading Upsetting

A large coil of metal wire is fed into and pulled through a drawing machine. The drawing machine compresses the metal wire material to the desired diameter and cuts it to the desired length. The resulting piece of cut metal is referred to as a metal blank or metal slug. The metal blank then passes into the cold heading machine.

Inside the cold heading machine, the blank is hit between a die and a punch block, pushing the material into the die to create the desired shape.

Cold Heading Extrusion

The cold heading extrusion technique includes two methods, forward extrusions and backward extrusion, also referred to as reverse extrusion. With forward extrusion, the cavity of the two dies is smaller compared to the diameter of the wire, which creates compression. With backward extrusion, the metal is forced backward through a punch to create a hole or cavity.

Forward Extrusions

This type of cold heading process involves feeding a metal slug into a cold heading machine. The machine’s dies and punches shape the slug by applying compressive force at room temperature, resulting in the formation of complex metal parts, such as fasteners. The 2 types of cold heading forward extrusions are:

• Open Extrusion: The cold heading open extrusion process involves deforming a metal slug at room temperature by forcing it through a die with an open end, typically used for producing parts with a consistent cross-sectional shape, such as pins or small rods.
• Trapped Extrusion: Cold heading trapped extrusion is a metalworking process that forms metal components by forcing a metal slug into a confined space within a die using a punch, allowing for the creation of intricate and precise shapes.

Backward Extrusion

Cold heading reverse extrusion or sometimes called backward extrusions is a metalworking process where a metal slug is placed on a die, and a punch is used to force the material to flow in the opposite direction of the punch movement. This process is often used to form the heads of bolts and other fasteners, creating features like flanges or large heads.

As industries demand more durable and high-performance parts, advancements in material science are pushing cold heading technology to new levels. Here’s how innovations in alloys and smart materials are shaping the future of cold heading.

Advancements in Material Science Driving Cold Heading Innovation

To meet the demand of industries that require exceptional strength and temperature resistance, metallurgists continue to develop new alloys. Recent developments in metallurgy have enhanced the capabilities of cold heading, allowing manufacturers to work with harder metal alloys made with titanium and nickel. 

Groundbreaking technology like smart metals, superalloys, and nanotechnology continue to push the boundaries of cold heading innovation, increasing the strength and durability of components manufactured using cold heading technology. 

Given the many benefits and recent advancements in cold heading, how do you know if this process is the right fit for your production needs? Let’s explore the best scenarios for choosing cold heading over other methods.

When should you choose cold heading for your parts?

Cold forming comes with advantages and disadvantages compared to other machining processes, such as screw machining. While using a screw machine may eliminate the need for dies, cold forming requires dies to set the head shapes, which increases the lead time and initial cost. A swiss screw machine also produces more material scrap.

The cold heading process is ideal for projects that require large quantities or if you are looking to reduce the need for secondary operations of a component in your current product lineup. Some of our clients had previously been machining parts which we were able to easily transfer to the cold heading process.

Since cold forming processes don’t involve the use of heat, you should consider this process when product strength is a priority. Cold working processes result in work hardening which affects the grain flow of the metal which typically results in a strong final product.

The cold heading process is commonly used for creating custom screws, bolts, and other custom fasteners out of round metal stock.

While cold heading is a type of cold forming, it’s important to understand the differences between these two processes. Let’s compare cold heading to the broader cold forming techniques.

Cold Heading & Cold Forming

Cold heading and cold forming are both manufacturing processes used to shape and create parts or components at near room temperature, but they are distinct techniques with different applications and processes. Cold heading is a type of cold forming process that is typically used to create products with a “head” like screws, bolts, and rivets.

Cold forming is the broader category used to describe an array of manufacturing processes performed without the use of heat. The basic types of cold forming processes include extrusion, forging, rolling, blanking, wire drawing, and more. As long as the manufacturing process is performed at room temperature, it can be considered cold forming.

Cold heading is versatile and can be applied to a wide range of industries. Here are some common applications where cold heading delivers superior results.

Cold Heading Applications

Above: Cold headed wheel studs manufactured by The Federal Group.

Cold headed products include items like simple fasteners, though with cold heading technology always improving, it can be used to create highly specialized fasteners and specialty pieces. This includes cold headed fasteners used in bridges, automotive manufacturing, electronics, specialty bolts, and other components.

Some common cold headed parts include:

• Screws and Bolts: The cold heading process creates various types and sizes of screws, bolts, and studs used in construction, agriculture, industrial, and other industries.
• Nuts: Different types of nuts, including hex nuts, lock nuts, and flange nuts, are often manufactured through cold heading processes.
• Rivets: Cold heading is used to create custom rivets, essential in construction,  machine assemblies, and heavy trucks for joining materials together.
• Pins and Fasteners: Cotter pins, dowel pins, and other fasteners are often produced using cold heading techniques for their precision and strength.
• Electrical Contacts: Small components like electrical contacts in various devices are often manufactured through cold heading due to the precision required.
• Metal Components for Consumer Goods: Items like furniture hardware, appliance components, and various metal parts in consumer goods are often produced via cold heading.

These products are used across industries due to the advantages of cold heading, such as cost-effectiveness, material efficiency, and the ability to create high-strength parts with minimal material waste. The versatility of cold heading means it’s used across numerous industries. From heavy equipment to electronics, here are the key sectors that rely on cold heading for precision and strength.

Industries Leveraging This Method

Cold heading is widely used as a primary metal manufacturing method. A broad range of industries rely on the accuracy and efficiency of cold heading to produce durable and reliable components. From the construction industry to the electronics sector, cold headed parts such as fasteners, connectors, and anchors can be manufactured with unparalleled strength and precision. 

In the medical industry, small parts and surgical instruments are manufactured using cold heading. Machinery parts and fittings are used in manufacturing, agriculture, and marine applications. The versatility and precision of cold heading allows for the production of specialized components in any industry that requires high-quality, reliable parts. 

The choice of material plays a critical role in the cold heading process. Let’s explore the materials best suited for cold heading and how their properties contribute to the final product.

Cold Heading Materials

Cold heading materials possess excellent formability characteristics and can be transformed into intricate shapes and fasteners without the need for heat. Their diverse mechanical properties make them ideal for a wide range of applications.

Softer metals typically form more easily while harder metals may require multiple blows in order to create the final product or specific shape.

The Federal Group utilizes a variety of materials for cold formed parts such as:

• Alloy steel
• Brass
• Bronze
• Carbon steel
• Copper
• Exotic metals
• Inconel
• Nickel alloys
• Specially blended materials
• Stainless steel
• Steel
• 17-4ph

The Future of Cold Heading: Innovations Shaping Tomorrow’s Manufacturing

Like all industries, the future of cold heading is being shaped by advances in automation and artificial intelligence. Automated systems and robotics continue to streamline production and enhance efficiency. With smart technologies, manufacturers can eliminate the risk of human error, leading to more consistent outputs. 

AI is used to predict when cold heading equipment might fail, reducing the risk of downtime. It can also be used to assess cold heading processes, taking factors like temperature, pressure, and speed into account. From supply chain management to energy consumption optimization, AI innovations continue to improve the efficiency of cold heading.

Ready to Unlock the Full Potential of Cold Heading? 

Discover how cold heading can lead to significant cost savings, efficiency, and production quality and transform your cold heading manufacturing processes. By streamlining production and reducing waste, an experienced cold heading manufacturing company can help you achieve greater sustainability and meet the demands of modern industries.

Contact us today to learn more about how cold heading can optimize your production methods and drive innovation for your business.