2024

What is Anodizing Dye?

Dyes used in the metal anodizing process are used to imbue the substrate of the parts with a range of available colors. Different hues can be created by altering the concentration of the dye, based on the specific needs of the part being anodized. The eventual application of the part will influence the ideal type of dyes and anodized colors available.

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Types of Anodizing Dyes

There are both organic and inorganic dye options available for anodizing. Organic dyes are generally made from acids or mordents, while inorganic dyes are derived from inorganic salts from various metals like tin, nickel or cobalt sulfide. Both are widely used, the choice between the two options usually comes down to the anodized part’s eventual function.

Applications of Anodizing Dyes

Parts that are anodized and dyed are used in a wide range of industries and applications such as:

• Aerospace
• Firearms
• Marine
• Medical
• Military & Defense

Choosing the Right Dye

Factors to Consider

The ideal anodizing dye choice is determined by a number of factors, such as the environment that the parts will be used in, desired color, lightfastness and overall compatibility. For instance, it is recommended that parts that are exposed to regular UV light or harsh environments should be colored with inorganic dyes since they offer better resistance, lightfastness and stability in these conditions. On the other hand, if the brightness or a wider range of color options are more of a concern, organic dyes are more suitable.

INCERTEC offers a variety of anodizing dye colors, including:

• Black
• Blue
• Gold/Yellow
• Gray
• Green
• Olive Drab Green
• Orange
• Red
• Violet

Environmental Considerations

The anodized dyeing process is growing in popularity in part because it is an eco-friendly option for coloring parts while also improving their core characteristics. Anodizing dyes are low-toxicity and comply with environmental regulations, producing no hazardous waste throughout the process.

Preparation for Anodizing Dye

Cleaning and Pre-treatment

Before parts can be anodized and dyed, they must first be cleaned thoroughly. Degreasing removes any dirt or particulate on the surface, acid etching then creates a surface that is more conducive to the anodizing process and then a thorough rinse ensures that the surface of the metal is as clean as possible going into the next steps.

Masking and Racking

If the entire surface of the part is not going to be anodized, the masking step is used to cover and protect those areas. Masking allows for aesthetic flexibility and customization during the anodizing process, while also allowing specific areas to retain properties like conductivity after the anodizing is complete.

Racking serves a vital function in both the anodizing and dyeing steps. Racks hold the part or parts securely in place throughout the entire process, while also being the electrical current pathway during anodizing. There are a number of racking techniques that can be used depending on the material and overall requirements of the parts being anodized.

What Materials Can Be Anodized and Dyed?

Nonferrous metals — and their alloys — can be anodized. Aluminum is the most commonly anodized material, but titanium and magnesium are also viable options.

Since its initial development in the 1980s, 3D printing has been gaining momentum in the manufacturing industry. Instead of subtracting from a block of raw material or injecting into a mold, a part is created by building the structure layer by layer using a computer file as the “recipe” and raw material typically in the form of a powder, resin, or synthetic filament.

While 3D printing is praised for its ability to create geometric shapes and accommodate design changes with greater ease than traditional manufacturing, there are material restraints that must be considered. The lightweight plastics and resins used are susceptible to damage or delamination under certain stresses and do not conduct electricity.

Electroplating and Metalizing 3D-Printed Parts

Parts can be 3D printed using metal coatings to avoid some of the above-mentioned pitfalls. However, this option is relatively expensive and not yet considered practical for large scale production. Continuing to 3D print with plastic material keeps the part lighter than the metal equivalents. Maintaining a lightweight product is notably important in the aerospace and automotive industries as they strive to maintain fuel-efficiency in a time when fuel costs and usage are on many minds. How can these 3D-printed parts be utilized on a larger scale unless they maintain a crucial strength and corrosion resistance?

Plating on 3D plastic couples additive manufacturing and metal plating; resulting in a final product that is lightweight and functional. The layer of metal deposited onto the 3D print provides the corrosion resistance, strength, and electrical conductivity necessary to allow the part to be treated like a traditionally manufactured part without the material waste or extra weight.

What 3D-Printed Materials can be Metalized and Electroplated?

With so many options for print material, it wouldn’t be practical to list them. There are a few properties that can improve your ability to metalize the polymer.

• Chemical Resistance: Plating processes use acids and salts that can cause chemical reactions with some materials. This can contaminate the plating solutions requiring costly repairs.
• Porosity:  The more you can fill your 3D print, the better chance you have in plating the material. The part will travel through several plating baths and a variety of chemistry. Each one needs to be effectively cleaned off the part before traveling to the next step. If the material traps solution, it will leach out in a subsequent step while decreasing the integrity of the deposit.
• Heat Resistance: Some chemical plating baths are heated. This requires the material to be able withstand a minimum of 200F without deformation.
• Glass or Mineral Reinforcement: Although not required, a 10% to 40% reinforcement has been proven to increase adhesion.

Learn More about plating on plastics and composites.

Properties Added by Electroplating 3D-Printed Parts

Most subtractive or injection molding parts require a final coating or treatment of some kind to protect the substrate from corrosion and improve longevity within the final application. By applying this necessity to 3D prints, manufacturers have more flexibility in creating large and small batches of a variety of designs without the need to invest in new, expensive equipment and hours of calibration. Applying plating on plastic parts increases the mechanical properties by protecting the substrate, adding conductivity, and strengthening the part overall.

• Strength: Resin used in 3D printers tend to be brittle and break easily. Adding a layer of metal to a 3D printed part will increase the ultimate tensile strength of the part.
• Conductivity: Plastics are insulators and metals are conductors. Adding metal plating to plastic, even selectively, allows the part to become electrically conductive. This added conductivity to plastic is very useful in the electric vehicle market and can be utilized in plating plastic connectors.
• Wear Protection: Depending on the thickness, a metal coating on 3D printed parts can have long-term wearability and corrosion resistance against external elements. Metals like gold and electroless nickel have very good abrasion resistance. Keep in mind that the thicker the plating, the heavier the part will become.
• Cosmetics: This is typically not what we focus on here at INCERTEC, but plating can be used to improve the appearance or be used as an identifier to a printed part.
• Electromagnetic Shielding: Plating is used to reduce or eliminate electromagnetic interference (EMI) or radio frequency interference (RFI) in the electronics industry.

Types of Metal Best Used With 3D Prints

Virtually any finish can be applied to a plastic substrate once it has been metalized.

• Gold – A noble metal when under normal conditions, does not oxidize or react chemically. Gold plating is frequently used in electronic and connector applications due to its oxidation resistance and durability.
• Electroless Copper – Typically used as a base layer on plastic substrates, electroless copper is conductive, ductile and deposits in a uniform layer over the substrate.
• Electroless Nickel – A co-deposit of nickel and phosphorus that mirrors the surface finish of the substrate with a Rockwell C hardness ranging from 41-51 when plated at a high or mid phosphorus co-deposit. Electroless nickel plating for 3D printed parts creates a uniform deposit onto the substrate since it is not dependent on an external DC current.
• Silver – A white luster semi-precious metal that boasts the highest thermal and electrical conductivity of all metals available in matte, bright, and semi-bright. Silver also has excellent solderability and lubricity.

When electroplating 3D prints, tin, cadmium and zinc-nickel are also suitable finishes to add to a plastic substrate. Contact us for a quote or to learn more.

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INCERTEC Plastic Plating Services

INCERTEC handles a wide variety of plating on plastic as well as plating on other unique substrates like composites, magnets, and ceramics. Contact us to discuss your plastic plating needs.