Finish options for metal stamping

FINISHING OPTIONS FOR METAL STAMPING

When designing and producing precision metal stamping parts, engineers and project managers representing manufacturers, their suppliers and metal stamping machines should discuss options for finishing parts to ensure optimum performance. Whether you need to inhibit corrosion, improve appearance or smooth out sharp edges, metal finishing is an important step in the manufacturing process and should be considered from the start.

Finishing options include:

• Powder Coating and E-Coating

• Plating

• Electropolishing

• Deburring

• Heat Treating

• Cleaning

Powder Coating and E-Coating

Coatings are applied to the surface of the part, the most common being paint, powder and metal coatings. Electroplating or electrocoating is often used as an anti-corrosion primer, while powder coatings are added for aesthetic reasons. Some applications, especially in the automotive industry, require both types of coatings.

Coating technology can be used for many valuable purposes:

• Increase      corrosion resistance

• Improve      the appearance of a part

• Serve as a primer coat to promote paint      adhesion

• Increase wear resistance

• Enhance chemical resistance

• Increase wear resistance

• Increase chemical resistance

• Reduce or increase the effects of friction

Plating

Metal plating is required for many custom metal stampings, from large automotive parts to tiny electronic components. Plating is primarily used to improve the appearance of parts, inhibit corrosion, increase electrical conductivity, and/or extend product life.

Plating can be specified in varying thicknesses. Plating materials include precious metals such as gold and silver, and non-precious metals like zinc and cooper. The cost of the plating material can be a significant factor in the overall cost of the part. The stamping itself should be designed to minimize material waste and maximize performance, taking into consideration the type of plating required.

Electroplating can be performed at different stages of metal stamping production, depending on the part and its function.

• Pre-plating of metal raw materials prior to      stamping may be less costly.

• Post-plating is done after fabrication and      is typically used for parts that operate in harsh environments or for      visual appeal.

• Spot plating is mainly used for precious      metals when only a small part of the stamped part needs to be plated.

Types of metal plating processes include:

·        Reel-to-reel plating

·        Barrel plating

·        Rack plating

·        Zinc or zinc nickel electroplating

·        Aluminum chromating

Electropolishing

Electropolishing removes the outer layer of metal and any contaminants by dipping the part in a bath filled with a mixed chemical electrolyte, then applying an electric current to the bath. Frame electropolishing is used for complex metal stampings with close tolerances, in contact with every part. More economical batch electropolishing is used for small parts such as fasteners and springs that do not require the same consistency in material removal.

Electropolishing is used to:

• Enhance the part’s appearance

• Prevent corrosion

• Debur minor flaws

• Improve fatigue life

• Perform ultra-cleaning

Deburring

Burrs are edges or small pieces of metal left on a part after stamping. Deburring is the process of removing excess material. Although secondary operations are relatively easy, deburring is often a suitable critical procedure.

Common methods of deburring metal stamped parts:

• Batch deburring processes are barrel and      vibratory finishing, tumbling or vibrating parts in abrasive media and      cleaning solutions. Both barrel and vibration finishing remove oil and      other foreign contaminants, as well as sharp edges and burrs.

• Electropolishing is a more expensive option      for microdeburring complex parts, removing surface metal to provide a      mirror-like finish.

Heat Treating

The heat treatment process involves heating and cooling metals, which alters their microstructure, resulting in physical and mechanical properties that make them more desirable.

Heat treatment allows metal stamping presses to use softer steel alloys to create more complex parts while still achieving the metal strength required for unique applications. The temperature to which the metal is heated and the rate of cooling after heat treatment can affect the properties of metal stampings. The most common reasons for heat treating metals are to improve part strength, hardness, toughness and corrosion resistance.

Two main types of heat treatment:

• The quenching or hardening process takes      place in a furnace and uses different media such as oil, salt or gas to      make the part harder, more wear-resistant, stronger, and then possibly      tempering.

• The annealing or softening process heats and      cools the part, making it more ductile and reducing internal stress and      brittleness.

Evaluating Metal Finishing Options During DFM

Using a metal press to discuss stamped part specifications and requirements early in the Design for Manufacturability (DFM) process can avoid unnecessary costs and schedule delays in metal finishing. Quality Precision Metal Stamping provides professional metal finishing operations utilizing in-house resources and verified suppliers. Working with an experienced metal stamping engineer familiar with a variety of finishing techniques can provide valuable insight and help you determine which finishing method is best for your final product.

For further assistance, please contact info@zec-industrygroup.com , +86 15858102851