Pre-Plating vs. Post-Plating Checklist: Which Makes Sense for Your Metal Stamping Project?

Tag Archive: metal finishing

  1. Pre-Plating vs. Post-Plating Checklist: Which Makes Sense for Your Metal Stamping Project?

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    Plating metal parts improves both performance and appearance, and can ensure your component functions properly in its application. 

    copper metal plated part

    Plating—a metal finishing process which adds layers of additional metal onto existing parts and components—increases conductivity, minimizes corrosion, reduces friction, and gives products a more pleasing and polished look. Plating can also make a product thicker or magnetize its surface.

    Read article: Which Metal Finish Works Best for Your Application?

    Plating may be performed before or after fabrication. With pre-plating, raw materials are plated with metal before they are shaped into specific parts. Post-plating is conducted after fabrication of the finished part.

    Pre-Plating Metal

    The primary benefit of pre-plating, in most cases, is its low cost. Coating raw materials is quicker, easier, and less expensive than coating individual finished products. If large amounts of material are likely to be cut away during production, however, pre-plating may not be worth the extra material waste produced. 

    To determine if pre-plating the right choice for your application, ask yourself the following questions.

    Will your parts be exposed to corrosion?

    Pre-plating means that edges and other cut-away areas won’t be plated after manufacturing, reducing their resistance to corrosion in these areas. Pre-plating is a poor fit for caustic environments.

    Does your design have complicated shapes?

    Post-plating often relies on a technique called barrel plating, where finished parts are tumbled around in the plating solution in order to coat them. Barrel plating is highly economical, but it can damage fragile or more complex parts that might tangle. If the final design will be too complex for barrel plating, pre-plating will be the better option. 

    chrome plated part

    Will your part require significant shaping?

    Extensive cutting, drawing, and other fabrication processes may leave some areas of your final product uncoated.

    brass metal plated partDoes appearance matter?

    If the final finish of the part is important, post-plating is most likely a superior option. While nickel and some other aesthetically pleasing metals are compatible with pre-plating, fabrication may leave the final part with an uneven finish.

    Will your part be hardened with heat?

    Heat treating doesn’t just affect a material’s physical properties, but often also alters chemical properties. Most heat-treated parts need to be post-plated to ensure the integrity of the coating.

    Post-Plating Metal

    Post-plating costs more than pre-plating and poses risks of dimensional issues on the workpiece. However, post-plating is also the only method that guarantees a part will be fully coated. Post-plating is an ideal—and often necessary—choice for parts that will be subject to harsh environmental conditions. It’s also an excellent choice when a visible component needs a more polished appearance.

    Keep in mind that plating won’t fix imperfections in your raw materials, and it can’t smooth rough surfaces. This means that your starting surface shouldn’t be rougher than the final finish you’re hoping for.

    Selecting the Right Plating Process for Your Metal Component

    Whether you ultimately choose pre-plating or post-plating for your products, quality and precision are critical to your results. At Engineering Specialties, Inc. (ESI), we specialize in metal stamping safety-critical components and always maintain superior quality control throughout our processes. We’re IATF-certified, Six Sigma Black Belt trained, and our team members are experts at minimizing defects.

    For your convenience, we’ve compiled a Metal Finishing Selection Guide with a chart detailing finishing solutions that improve corrosion resistance, surface hardness, and other mechanical property enhancements to their metal components.

    metal finishing selection guide


    ESI can source pre-plated materials for your projects or directly handle post-plating them. Our experts will consult with you to help you decide which is the best choice for your applications.

    Contact us today to find out more. We look forward to working with you.

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  2. Which Metal Finish Works Best for Your Application?

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    Manufacturers turn to metal finishing solutions to provide corrosion resistance, surface hardness, or other mechanical property improvements to their metal components.

    barrel paint finish

    Metal finishing may involve different coating techniques including electroplating, where the coating and the metal components are immersed in an electrolytic “bath.” An electric current is then applied to oxidize the metal atoms, depositing the coating onto the component and changing its surface properties.

    Because many of ESI’s metal stamping customers ask questions about the best finishing options for their projects, we’ve teamed up with one of our finishing partners – Northeast Metal Works – to put together a short step-by-step guide on selecting the appropriate metal finishing for your project.

    Step 1: Identify Corrosion Resistance Needs

    Different finishes offer varying degrees of corrosion resistance. It’s essential that materials are matched to both the environment they’ll be operating in, as well as to the length of time they can resist corrosion.

    ESI examined some of the most popular metal finishes, the applications using those finishes, and the hours each finish could withstand damage caused by oxidation or other chemical reactions. These finishes were then categorized by their salt spray test results — a standardized corrosion test method where salt spray is applied to coatings and appearance is evaluated over time. The longer the period of time before corrosion or rust appears, the higher the material’s corrosion resistance.

    corrosion resistance key

    High corrosion resistance indicates that a finishing material can protect a component from salt spray for over 1,000 hours, while some finishes may only provide protection from water alone for up to 50 hours. For example, here are two finishes that feature significantly different results:

    • Imitation chrome tends to be costly because of its aesthetic and corrosion-resistant properties. Offering a bright silver finish, excellent lubricity and corrosion resistance, imitation chrome is also environmentally friendly and is sought by manufacturers in the marine and medical industries.

    imitation chrome metal finish

    • Zinc is not as resistant to corrosion as imitation chrome, making it lower in cost. That being said, it offers other notable properties like ductility and adhesion, making it an ideal finish for automotive and industrial manufacturers.

    zinc metal finish

    Step 2: Analyze Pricing

    Pricing is a significant factor in the finishing selection process. The level of corrosion resistance and aesthetic qualities will impact price, but keep in mind that other factors can influence pricing, as well, including:

    • Market conditions
    • Finish availability
    • Complexity of coating process

    For example, barrel paint is widely considered to be an inexpensive finish. It is frequently utilized by the consumer product and construction industries due to its ready availability in many colors.

    Barrel paint can be cheaper than powder coating options and offers full coverage. However, it is not nearly as durable as a powder coat. It can also only be applied to parts with simple shapes. This influences how pricing actually plays out over the lifetime of an item and what that means for your company’s budget.

    Step 3: Consider Other Needs: Aesthetics, Thermal Conductivity, and More

    Products that will be visible in their end use typically require aesthetic considerations. When selecting finishes by aesthetic appearance, factors include:

    • Color availability
    • Matte vs. gloss choices
    • Smoothness

    Based on the application, electrical or thermal conductivity may come into play as well. The medical industry in particular often requires components that offer electrical or thermal conductivity. Furthermore it is essential that coatings for medical devices – such as pacemakers or artificial hips – do not pose any harm to human tissue. As such, the cytotoxicity potential and medical cleanliness of surfaces must be taken into account, and should play a part in the selection process for finishing materials.

    If you aren’t sure which finishing option is best for you, work with an expert. ESI offers complete services from design to delivery so you can receive a finished metal component without having to worry about moving it between providers. For more information, download our Metal Finishing Selection Guide today.

    Learn how to select the right finish

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