10 Types of Sheet Metal Finishes

Many industries, such as automotive and aerospace, rely on sheet metal fabrication to produce parts and components. And when it comes to the manufacturing process, sheet metal finishing is one of the most important steps to consider.

Sheet metal finishes come in a variety of options and each has advantages and properties that set it apart from the others. Learning more about them enables you to choose which is appropriate for your next project.

Raw or Rough Finish

This type of sheet metal surface finish occurs when no finishing is applied to the completed product. A raw finish (sometimes referred to as a rough finish) is frequently used if the base material is already suited for the environment in which it will be used. 

For example, in some cases, stainless steel sheet metals are used outside because they are corrosion-resistant and do not require further polishing.

Some examples of raw finishing include equipment in pharmaceutical and chemical plants, jewelry, air conditioners, and automotive designs.

Electroplating

Electroplating is a sheet metal finishing technique that’s also known as electrodeposition. It involves applying another layer of metal (substrate metal) to the surface of the sheet metal. The substrate metal is usually lighter or less expensive  and is encapsulated in a thin shell of metal. This type of finishing is prevalent in gold-plated watches, silver-plated teapots, or chrome-electroplated faucets.

Bead Blasting

Bead blasting is less aggressive than sandblasting sheet metal finishes. Bead blasting uses sand or glass beads to achieve a matte finish. It’s primarily used to remove any tooling marks and blemishes. Therefore, achieving a more uniform and aesthetically pleasing surface. This is common for finishes in automobiles, floorings, and cabinets.

Anodizing

Aluminum anodizing is a sheet metal surface finish process that makes the surface corrosion-resistant through an electrochemical process. It converts the surface of the sheet metal into oxide, which is very thin but highly durable. Anodizing is a common sheet metal finishing process for automotive finishes and mechanical parts. It can also be classified into three types:

•   Type I: This type creates a thin but highly corrosion-resistant coating using chromic acid.
•   Type II: Instead of chromic acid, sulfuric acid creates a durable and highly corrosion-resistant finish.
•   Type III: It produces a thick metallic finish, which is wear and corrosion-resistant.

Anodized parts are evident in interior and exterior building finishes, bathrooms, doors, windows, and roofs.

Electroless Plating

Electroless plating is a process also known as auto-catalytic or chemical plating. Instead of electrical means, it plates metal chemically. It involves the process of deposition of metals on a surface of sheet metal through a reducing chemical bath. It creates a catalytic reduction of metal ions that plates the part. Some of its advantages include the following:

•   Creates an even layer
•   Offers flexibility in thickness and volume
•   Provides bright, semi-bright, and matte finishes

Electroless plating can be used for brake pistons, pump housings, pipe fittings, injection molds, dies, food molds, and many more.

Powder Coating

Powder coating is another aesthetic process where a dry powder is sprayed on the surface of the sheet metal. It uses a combination of modifiers, pigments, and other additives to create the powder coating. After that, the sheet metal is baked to produce long molecular chains, resulting in cross-link density. This type of finishing is commonly used in industrial equipment and household items.

Phosphate Coating

Phosphate coating is also known as phosphatization. It’s mainly applied to steel parts through a chemical treatment, where a thin adhering layer produces strong adhesion and corrosion resistance. 

The coating is composed of zinc, iron, or manganese phosphates. The finished product is a gray or black appearance and is typically used in the automotive industry.

Electropolishing

This method uses an electrical current to remove the metal ions from a metal part. It creates a smooth and shiny surface texture that decreases cleaning time, improves corrosion resistance, removes peaks and valleys, and eliminates debris. Electropolishing is useful in the food and beverage, medical, automotive, appliances, and furniture industries.

Buff Polishing

Buff polishing is a finishing process used to clean and smoothen the sheet metal surface. It uses a machine that has a cloth wheel. 

Many manufacturers also use it to create a polished and decorative look that’s visually appealing. Pharmaceutical and food industries commonly use this type of finishing.

Abrasive Blasting

Abrasive blasting uses high-propulsion equipment to stream an abrasive material on the surface of sheet metal. It saves time and money by combining surface finishing and cleaning. 

Furthermore, it can be used as a surface preparation treatment before coating, plating, or painting. Some industries that use this finishing include automotive, engraving, construction, and many more.

Choose the Right Process to Achieve the Best Sheet Metal Finish

Each type of sheet metal finish has unique benefits that make it ideal for different applications. When choosing sheet metal fabrication services, the Federal Group USA has capabilities that can meet your needs. Contact us today, and we’ll guide you through our process.