Posted on May 20th, 2019 | By Hazel, WayKen Project Manager
Aluminum Anodizing is an electrochemical process which converts the aluminum surface into a decorative, durable, corrosion-resistant, and wear-resistant oxide layer. This aluminum oxide is not applied to the surface like coating or plating, but is fully integrated with the underlying aluminum substrate.
The anodized aluminum sheet cannot chip or peel easily, and it has a highly ordered, porous structure which allows secondary processes such as coloring. The anodized aluminum colors can meet customers’ various color needs, and can be customized according to Pantone Color number. Also anodized gold is a common case for anodized aluminum colors.
Here are two main types of aluminum oxidation: one is electrochemical oxidation, also called anodization; the other one is chemical oxidation, also known as chemical conversion. Electrochemical oxidation is further divided into: 1 sulfuric acid anodizing; 2 chromic acid anodizing; 3 oxalic acid anodizing. The sulfuric acid anode is also classified into ordinary anodizing, hard anodizing, and porcelain anodizing. Chemical oxidation mainly include: chromate oxidation (also divided into conductive film or non-conductive film), phosphate oxidation and phosphate-chromate oxidation.
Among them, hard anodized aluminum is a preferable choice for most customers who need aluminum anodizing service. Aluminum hard anodizing, also known as MIL-A-8625Type III or engineered anodizing, is similar to standard anodizing in that both are controlled electrochemical processes. The key difference is that hard coat aluminum anodizing provides a surface that is more wear resistant and has a smoother and harder finish than standard anodizing. Hard anodizing is commonly performed clear or with a black dyed finish, though some prefer the aluminum dyed different colors for aesthetic appearances.
Three Key Factors Affecting the Anodizing Aluminum Cost
Regarding to the cost of anodized aluminum sheet, although it depends on different requirements, there are three key factors that affect anodizing aluminum cost. The anodizing aluminum cost mainly depends on the thickness of the coating, the size and shape of the part, and extra services desired.
Coating Thickness
If no specific thickness is require for the coating type it is considered “basic” and is the least expensive.
Controlling precise coating thickness affects cost. If coating thickness specifications include upper and lower limits, the narrower the range, the higher cost. As an example, +/- .001” is less expensive than the tighter range of +/- .0001”. Maximum coating thicknesses may also cost more because they take longer to produce.
Racking
Racking is critical to quality. Aluminum or commercially pure titanium racks will be used to make electrical contact. If the job does not specify racking requirements, the manufacturer will utilize the most cost-effective method to gain the highest yield. Particular racking requirements may limit the number of parts processed at one time and the cost per part may go up.
The number of parts anodized at one time is affected by power supply limitations. Anodizing is performed at 15 or 30 amps per square foot (ASF). Therefore, there is a maximum surface area able to be processed in each run.
Extras
Customers often require additional processes to augment the anodizing process. When parts need simple or complex masking or if holes need to be plugged, those services add labor and time. While those services add value, they also increase the total anodzining aluminum cost.
Above these anodizing alumium methods, you can decide which process is more suitable or right for your metal and other prototype parts. If you need some solutions to deal with the surface fish of functional aluminum parts that will face corression or wear, such as aircraft parts or consumer goods, this post-processing can be more affordable compared to painting and powder coating.
How to Make High Quality Anodizing Aluminum Parts
- Professional aluminum anodizing service.
- Quality anodized aluminum process. The intended colors and glosses of final aluminum anodized parts somewhat will be affected by anodizing technology.
- Select quality aluminum materials to surface preparation before anodizing parts. When anodizing small aluminum parts, the anodizing result will be affected by the aluminum material composition.
- Advanced CNC milling. The strong CNC milling service can get the tight machining tolerance so that further improve the surface finish for finishing aluminum parts.
Conclusion
The anodized aluminum strengthens its performance in corrosion resistance, and provides better adhesion for paint primers and glues than bare metal dose. Anodizing film can also be used for aesthetic purpose, either with thick porous coatings that can absorb dyes or with thin transparent coatings that add interference effects to light reflection. And regarding to concerns of anodzining aluminum cost, customers and manufacturers need to focus on the needed thickness, numbers of racking and extra need so as to make reasonable production decision.
If you want to learn more about how anodizing aluminum can help enhance your prototypes and parts, please feel free contact us to discover how our engineers can enhance your own production plans. Also, here are more CNC aluminum services you may want to know.
