When you need a high-quality part or assembly, every last detail matters—including, of course, the color. But did you know that a finishing process like anodization doesn’t always produce a consistent color every time?
If you select black or clear anodize, you probably won’t run into this problem. But once you introduce other colors to a part, the risk of variation increases. Take blue anodized parts, for example. Depending on different factors, the hues could range from nearly navy to a sunny sky blue.
It’s important to set the right expectations about color consistency for anodized parts. But we also have some tips for ensuring better, brighter colors.
Factors That Cause Color Variation During Anodizing
First, let’s look at the main factors that cause color variation during anodizing:
1. Differences among components
If you have an assembly with multiple components, you may be dealing with various materials. Furthermore, each component may undergo a different machining process. Both of these factors can impact color variation.
If, for instance, we remove material from deep into the grain of one component versus another, the extrusion surface may break and expose raw material, resulting in a different color hue after anodizing.
2. Inconsistency between batches
Not all components in an assembly are anodized in the same batch.
Suppose you place an order for 20 assemblies, with each assembly containing 5 different components. All the parts need to be blue, but the anodizer is unlikely to dip each assembly one at a time. Instead, they’ll typically batch anodizing by each part type. Once the assembly is complete, you may notice color variations among the 5 components.
3. Sequence of parts.
Parts are anodized in sequential order, and those that are dipped last tend to have lighter hues. This concept applies even in the same anodizing tub.
If you’ve ever dyed Easter eggs with your kids, you’ve likely seen this phenomenon firsthand.
Strategies for Achieving Color Consistency in Anodized Parts
Fortunately, there are ways to take control of the anodizing process and achieve better color consistency:
1. Place uniform orders.
If your components will be assembled side by side and you need the colors to match, order those parts at the same time and be sure to communicate the reasoning to your supplier. They can help ensure that the components are part of the same batch.
2. Provide an approved sample.
Believe it or not, images aren’t very accurate for color matching. A better alternative is to provide an approved sample and an approved range of hue variations for your part color.
3. Consolidate your supply chain.
One of the best ways to ensure color consistency is to send parts to the same anodizer. At Reata Engineering, we specialize in managing supply chains for our customers and will do our best to make this happen. We’ll even consolidate machined parts that come in from various contract manufacturing companies before sending them for anodizing.
Remember that color variation is still possible even with these strategies in place. If consistency is your primary concern, your best bet is to select black or clear anodize.
Need a contract manufacturing partner that will work with you to help you make the right decisions and get the highest quality parts and assemblies? Request a quote from Reata Engineering, and we’ll respond within 24 hours.