Are you exploring metal finishing options for your enclosure? This month’s metal enclosure design tips post focuses on all aspects of metal finishing. If you missed September’s tips on metal joining techniques and the differences between welding, mechanical joining and adhesive bonding, check it out here.
Metal finishing generally refers to an operation that alters a metal's surface to achieve the desired property, whether it’s for a shiny look or to harden the metal for strength. Contrary to its name, metal finishing processes aren’t always the last step in metal fabrication, and should be considered early on in the design process
In this blog, we will answer:
Whether you’re in the pre-planning or design phase of your project, now is the time to start thinking about metal finishing.
Metal finishing should be an early consideration in the manufacturing process to improve the qualities of the metal you’re working with. Without metal finishing, your end product can have visible flaws, be more prone to rust and other environmental stressors and lack durability.
Metal finishing can improve:
Aesthetics: Aesthetics can be essential if your enclosure is in a consumer environment, such as self-checkout kiosks or other point of sale kiosks. Finishing techniques such as painting and polishing, improve the final product look and feel.
Durability: Deburring and removing sharp edges can improve product quality and remove potential safety hazards. Heat treating and properly curing metals protects enclosure quality and allows it to withstand time and use.
Environmental Protection: Unfinished metals can be more prone to environmental stressors such as temperature changes and rain, snow, ice and dust. These stressors can corrode metals, causing them to rust. Finishing solutions alter the surface of metals to make them more resistant to these conditions.
Now that we know the benefits of metal finishing, let’s look at metal finishing techniques.
Metal finishing solutions cover everything from deburring to painting and plating. There are a wide variety of techniques to fit unique metal requirements. Here are a few common finishing solutions and their main uses: Grinding: Grinding is a popular method that uses wheels to polish away roughness from welding, machining or other processes. There are different types of grinding machines, including surface grinders and die grinders, but they all operate in similar ways, using an abrasive moving substrate to smooth out imperfections.
[Example of a hand grinder]
Blasting: Bead blasting and sand blasting are two common methods that polish metal by blowing dry sand or beads against it. This finishing method can cut costs by adding cleaning and finishing into one process. Wet blasting is another method, which uses hot water and an abrasive slurry to clean and polish metals.
Polishing/Buffing: - Polishing smooths out the surface of a metal and enhances its natural shine. Similar to grinding, polishing uses an abrasive to buff away imperfections. The metal type will determine what kind of abrasive and method to use, either robotically or by hand.
Heat Treating: Heat treating covers a variety of processes. It can either harden metal for durability and remove brittleness or soften the metal to make it more malleable and easier to bend. Annealing, tempering, case hardening and normalizing are examples of processes that fall under the “heat treating” category. While there are many types, the primary function is always the same: to change the metal’s physical properties and improve its structure.
Coating: Wet or powder coat paint protects enclosures from corrosion and other environmental stressors. Powder coat paint is considered to be more durable and cost-effective than wet paint for metal enclosures, as well as more environmentally-friendly. Powder coat paint is also cured with heat or UV light to provide an extra layer of protection against the elements.
[Maysteel powder coat capabilities]
Plating: There are three main kinds of plating: electroplating, electroless plating and immersion plating. Thomasnet describes the plating process as, “Metal plating uses chemical baths to coat or alter the surface of substrates with thin layers of metal such as zinc, nickel, cadmium, or chromium. The electroplating method generates an electric current to coat the substrate, while electroless plating employs an autocatalytic process in which the substrate catalyzes the reaction.” Immersion plating is different because the reaction is from the metal substrate rather than the mixture of two chemicals in the bath. Immersion plating creates a thin metal deposit, usually zinc or silver. Because plating is a chemical process, it is usually found in specialized fabrication shops.
Anodizing: This is a passivation process most commonly used on aluminum, which increases the natural oxide layer's thickness to provide protection and aesthetics to metal’s surface. The metal is submerged in an acid bath and an electric current passes through it.
How do you choose the right finishing solution for your metal enclosure? Use the considerations below to guide you through the process.
Project Cost: Metal finishing can affect the total product cost of an enclosure. Some processes are more manual than others, resulting in higher labor costs. For example, bead blasting, a manual process, has a higher labor cost than polishing, an automated process.
Metal Type: All metals have unique chemical makeups and characteristics. We already discussed anodizing for aluminum. Titanium, a non-ferrous metal, can also benefit greatly from anodizing. Stainless steel is also commonly polished to a shinier finish than other metals for aesthetic and cleanliness purposes.
Project Timeline: As we mentioned prior, some finishing methods have longer timeframes. Automated processes will almost always be quicker than manual processes. Planning your finishing solution ahead of time can also make or break your project. Make sure you discuss your options with your manufacturing partner so they can ensure your enclosure gets the finishing solutions it needs.
Project Complexity: As mentioned above, some finishing methods can’t be performed on already bent panels, so if you have a project that requires more complicated manufacturing processes, make sure you begin that conversation early with your fabricator to make sure they can meet your needs.
We discussed the benefits of metal finishing, different metal finishing processes and how to choose the ideal one for your metal enclosure. Choosing the most effective finishing solution for your enclosure is only one step in the design process. Are you working on a current project? Get answers from our previous blogs in the Metal Enclosure Design Tips series:
Maysteel offers finishing solutions throughout our five manufacturing locations, including grinding, polishing, bead blasting, and wet & powder coat paint. If you’re looking for a fabrication partner for your metal enclosures, talk to our team today: https://www.maysteel.com/contact/
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