Cold Forging: The Process in Detail

The process of cold forging economically shapes metal components. Instead of removing material, the metal is shaped into its final geometry at room temperature using high pressure – often without the need for machining. Walter Schneider develops, designs, and manufactures the tools – and realizes high-precision series components made of stainless steel, nickel, copper, or aluminum.

What exactly happens in Cold Forging – and when is it worthwhile?

In cold forging, a metallic blank is pressed into a closed tool at ambient temperature under high pressure – without additional heating. The material flows in a controlled manner into the desired geometry while preserving the grain structure, which significantly increases the strength of the component.

This process is particularly suitable for medium to large series with strict requirements for dimensional accuracy and repeatability – such as in the automotive sector, electrical engineering, or machinery & plant engineering. Cold forging can offer both economic and technological benefits from quantities of 50,000 per year.

Cold Forging Process Flow – Step by Step

Cold forging is a non-cutting bulk forming process where metallic materials are plastically deformed at room temperature under very high pressure. The goal is to economically produce complex component geometries with high dimensional accuracy, strength, and repeatability. The process unfolds in several defined steps, with material flow and tool design playing a central role.

Preparing the Blank: At the beginning, a suitable blank is prepared – usually a cylindrical section from wire, bar stock, or a pre-machined metal part. It is crucial that the material has good forming properties, being ductile enough to deform under high pressure without tearing. Depending on the material, the blank is cleaned, lightly oiled, or minimally pre-heated before forming – however, the temperature always remains below the recrystallization point to deliberately exploit cold work hardening.
Inserting into the Tool: Subsequently, the blank is precisely placed into the tooling system mounted in a mechanical or hydraulic press. This essentially consists of a die (outer shape), a punch (power transmission), and, if necessary, a mandrel (for hollow shapes). The exact tool design decides the direction in which the material will later flow and which geometry will result. The system must operate with high precision to maintain tolerances within the sub-tenth millimeter range.
Forming under High Pressure: In the actual forming phase, the blank is pressed into the tool by the punch with high force – typically between 250 and 2,000 kN. The material flows into the free spaces of the die and takes the desired shape. Depending on tool design and process strategy,the material can be deformed in the direction of punch movement (forward forging), against the punch movement (backward forging), or laterally to the punch movement (lateral forging). Cold forming results in significant work hardening of the material – the structure is compacted, the grain flow is retained, and the strength is significantly increased.
Removal and Post-Processing: After the pressing process, the component is either automatically or manually removed from the tool. Subsequently, optional steps follow – depending on geometry and requirements – such as trimming flash, punching or stamping inner areas, calibrating for fine-tuning dimensions and roundness, or even heat treatments for strength enhancement. Clean process management can often eliminate or significantly reduce additional machining steps.
Quality Assurance: Finally, quality control is carried out, employing various testing methods depending on the application and industry. These include dimensional checks using a measuring machine or optical scanner, strength tests, surface analyses, and – for safety-critical parts – metallographic inspections to monitor grain flow and microstructure.

When Cold Forging Is the Right Choice

Cold forging is not necessarily a substitute for other methods but a targeted alternative when certain requirements are met. The process is particularly advantageous in the following applications:

When high dimensional accuracy and repeatability are required – such as in press-fit, plug, or guide parts.
When material saving is crucial – for example, with expensive materials like stainless steel or lead-free copper.
When a high level of production automation is required – for instance, in series for medical technology or automation technology.
When high component strength is needed – such as for safety-relevant components or mechanically stressed parts.

The cold forging process is therefore always useful when function, dimension, and quantity impose the highest demands – and economical production is required.

Which methods are used in the Cold Forging Process?

The cold forging process consists of various forming principles, which are combined depending on component geometry, function, and forming direction. The three central methods are forward forging, backward forging, and lateral forging.

Forward Extrusion

In forward forging, the material is deformed in the direction of the punch movement. The metal flows through the tool, extending axially. This method is particularly suitable for elongated, rotationally symmetrical components such as bolts, sleeves, or axles, where the outer contour is in the foreground.

Backward Extrusion

Backward forging utilizes an opposite material flow direction: the blank is deformed against the punch movement, causing the material to flow back past the punch surface. This technique is ideal for producing hollow bodies with closed bottoms – for example, for cup shapes or closed housings.

Lateral Extrusion

In lateral forging, the forming occurs transversely to the main pressing direction. Here, the material is specifically displaced laterally to create transverse ribs, flange areas, or complex cross-sectional profiles. This process is particularly suitable when the final geometry has lateral extensions or irregular shapes.

By combining these methods, demanding component geometries can also be realized – precisely, dimensionally stable, and process-safe.

For which components is the Cold Forging Process suitable?

The process is particularly suitable for components that meet these requirements:

Series requirement: Annual production volumes starting at approximately 50,000 components
Functional precision: Dimensional accuracy, reproducibility, and strength are crucial
Geometry: Rotationally symmetrical or hollow, possibly with transverse shapes or flanges
Materials: Stainless steels, copper (also lead-free), aluminum, or special alloys

Typical examples:

Mechanical engineering: Housings, hollow bodies, guide bushes with defined fits
Electrical engineering: Precision sleeves, conductive contacts, shielding housings
Medical technology: Robust miniature components with defined inner and outer geometries
Bicycle and sports equipment manufacturing: Lightweight yet durable connectors with complex shape requirements

By combining multiple forming directions (forward, backward, lateral), even complex components can be economically and precisely realized.

Contact

Do you want to know if your component is suitable for the cold forging process?
Then let us assess together how your component can be implemented reliably, economically, and with precision using the cold forging process.