Difference Between Coining And Embossing Sheet Metal Operations

What Is Coining?

Metal coining is a forging process by which very fine and intricate details can be created on the surface of a workpiece. Coining may be used to control surface quality and detail on parts. Metal coining is often a finishing process for manufactured products. This is a flashless, precision forging operation that due to the required accuracy of the process, it is performed cold.

In this process, lubrication is not used, since any substance between the die and work would hinder the reproduction of the most accurate details that are to be formed on the work’s surface. In the coining process, a large amount of force is exerted to a portion or the entire surface of a forging. The surface of the metal workpiece is positioned parallel to the dividing line of the forging. This process is considered a method of precision stamping, in which the metal workpiece is subjected to high stress to induce plastic deformation in the shape of the die.

Coining is not a process that removes materials as in traditional stamping operations that use a punch and die to cut. Instead, the coining tool applies tremendous force to the workpiece and creates the desired shape by displacing material.

Coining is used to manufacture parts for all industries and is commonly used when high relief or very fine features are required. Some of the typical applications of coining include:

• Minting coins and medallions and other similar products on flat stock with relief features.
• Making badges, buttons, precision-energy springs and precision parts with small or polished surface features.
• Making complex electronic parts
• Making of jewelry

What You Need To Know About Coining

• Coining is a metalworking operation used to create raised surfaces and imprints in metal. Coining is relatively severe operation that creates variations in metal thickness.
• This is used for making works on metal like coins, medals etc due to the fact that it produces finer and detailed surface finish.
• Coining operation under cold working requires more force.
• Pressure required at work is more than the embossing.
• Coining eliminates the need for complex finishing processes.
• In this operation, at the time of work, deformation occurs only at the metal or just surrounded by it.
• When the force is applied to it, the flow direction of metal is perpendicular to the applied force.
• The work hardened surface can resist impact and abrasion.

What Is Embossing?

Embossing is a metal forming process for producing raised or sunken designs or relief in sheet materials by means of matched male and female roller dies, theoretically with no change in metal thickness or by passing sheet or a strip of metal between rolls of the desired pattern.

Metal sheet is drawn through the male and female roller dies producing a pattern or design on the metal sheet. Depending on the roller dies used, different patterns can be produced on the metal sheet. Some of the most common pattern include: stucco, leather grain, wood grain, weather grain and rough sawn cedar. Most embossers will tool to form any needed pattern, depending on the cost parameter involved.

Materials commonly used in the metal embossing process include:

• Aluminum alloys
• Steel alloys
• Zinc
• Copper
• Galvanized steel
• Brass
• Cold rolled steel

What You Need To Know About Embossing

• Embossing is a metalworking operation used to create raised surfaces or lettering in sheet metal. There is theoretically no change in metal thickness during embossing.  
• The process has ability to form ductile metals and produce unlimited patterns, depending on the roll dies.
• Embossing operation is used in drawing on metals, jewelry shapes etc due to its ability to produce products with no variation.
• This type of operation uses less force at working than coining operation.
• It uses less pressure when compared to coining operation.
• In this operation, the effect shows on complete body thickness.
• When the force is applied, the flow direction of metal is along the applied force.
• The process has ability to maintain the same metal thickness before and after embossing.
• Embossing is used in medium to high production runs.

Also Read: Difference Between Hot Working And Cold Working Process

Difference Between Coining And Embossing In Tabular Form

Also Read:

• Difference Between Forging And Casting
• Difference Between Open-Die Forging And Closed-Die Forging