Prior to the beginning of an actual process of plating, firstly, it’s important to mold the part of the plastic. If you’ll do the proper molding, the part will be stressed and eliminate the imperfections of the surface. This will reduce the quality of the part. It’s important to learn that the part should meet certain specifications of polishing, melting at an appropriate temperature, and resin dryness.
It’s true that plastic is composed of the non-metallic property, so it’s important to metallize it before applying the chrome plating on it. This will improve the adhesive property of material. To achieve this, you’ve to opt out the process called electroless plating.
In this process, the metal is deposited on the substrate’s surface that introduces the electric current inside the bath used for plating.
Steps of electroless plating
The process of electroless plating involves certain steps that include:
Cleaning – Firstly the substrate’s surface should be cleaned that usually removes the dirt, finger prints, and other marks. It can be done with mild alkaline cleaner. You can also use the chromic acid solution for thorough wetting.
Pre-dipping – Dipping the parts made of plastic in a solvent prior to etching improves the surface of plastic that has been poorly molded and are highly stressed.
Etching – Etchants are mainly composed of chromium trioxide or an acidic solution of sulfuric that usually increases the substrate’s surface. This enables it to easily absorb the liquids. It also produces tiny holes that bound the part with the metal deposited on it.
Conditioning – It’s an extra step, which is optional that usually occur after etching that includes the process of applying conditioner to the substrate.
Neutralizing – Next step is of neutralizing that removes excess of acid or any other material left on the part. You’ve to apply the neutralizer that ensures that the excess of the etchant is removed from the surface.
Pre-activating – A pre-activator is one of the products that basically facilitate the absorption during the subsequent activation step. These products work in a good way with resins like polyphenylene and polypropylene oxide.
Activating – This step involves the introduction of a precious metal liquid activator having the low concentration that’s usually served as a catalyst during the process of plating. Typical metals found in the activators include platinum, palladium, and gold.
The Accelerating step – To remove the stannous hydroxide from the surface of the part, accelerators are used that enables the activator to effectively work as a catalyst and prevent the occurrence of skip plating.
Bath Immersion – The next and the last step is to place the part in the electroless bath in which a thin coating of metal will be deposited.
After all the above steps of metallizing the part, you can start with the chrome plating of the metal for giving a finished look to it. You can use nickel or copper because nickel makes the plastic surface conductive and copper is used as the automotive part being least resistant to blister.