Metal Finishing: How It Works and Why It’s Important

Industrial Metal Finishing

Every day, we’re surrounded by various metals that play a crucial role in our lives, from computers and phones to jewelry, tools, and cars. These metals, such as copper, tin, zinc, lead, and nickel, are some of the most common materials we encounter daily. While less common in everyday items, precious metals like gold, silver, and platinum still have a significant presence in our lives, adding value and functionality to the objects we use.

Each one of these metals is naturally occurring in our Earth’s crust and is therefore beneficial in its own way. But each metal also has its weakness that can be improved to increase its utilization. This is why metal finishing is necessary.

Metal finishing is the process of applying a certain type of metal coating to the surface of a metallic part, typically called a substrate. Metal finishing can also be the process of cleaning, polishing, or generally improving a metal surface. Metal finishing sometimes involves electroplating, which is the process of depositing metal ions onto a substrate through an electric current. Metal finishing and the term “plating” are often used interchangeably. Overall, the metal finishing industry includes a variety of processes, each with its own benefits. 

Purposes of Metal Finishing

• Clean, polish, and remove surface defects
• Limit the effects of corrosion
• Serve as a primer coat for paint adhesion 
• Reduce the effects of friction
• Enhance chemical resistance
• Make a surface electrically conductive
• Increase solderability
• Improve the appearance of the part

Commonly Used Industrial Metal Finishing Processes

Electroplating

Electroplating, also known as electrodeposition, is the process of depositing a metal or metal alloy onto the surface of a substrate. An electric current is passed through a liquid called a bath that holds dissolved ions of the metal and the substrate. The metal object acts as a cathode and attracts metal ions found in the plating bath.

Before electroplating can be complete, a pretreatment process must be applied that consists of cleaning, rinsing, and stripping the substrate. There are two common bulk methods of electroplating: rack plating and barrel plating. In rack plating, the metal parts are fixed to a jig. In barrel plating, smaller metal parts are tumbled inside a barrel-shaped cage.

Passivation

Passivation is used as a post-treatment plating process to provide additional protection against corrosion damage. The passivation process includes applying a metal oxide coating that can deter rusting for a longer period of time. Most passivation applications are available in a variety of colors, which also enhances the appearance of the finished metal or part.

Shot peening is a successful method to reduce metal fatigue and stress. This method prevents failure caused by corrosion and increases the durability and lifespan of the metal. Shot peening is the process of using specially designed equipment to blast small projectiles known as shots. These projectiles can be made of ceramic, metal, glass, or other materials. The compressions cause plasticity to occur.

Choosing A Metal Finishing Process | Metal Finishing Near Me

There’s a lot to consider when choosing an industrial metal finishing process. You should consider turnaround time, the hardness of the metal, and cost. Each of these factors will determine which metal finishing process is best for you. If your next project requires parts with metal finishing, consider contacting your local manufacturer for metal finishing near me.