Vacuum Metalizing

To make chrome coating on plastic is not a simple process, this coating process in industry is not use a chromium plating as usual done on metal or steel. They use vacuum metalizing process on chamber with vacuum pressure. Metal evaporate inside vacuum chamber which then bonds to the desired parts to achieve a uniform metalized layer, like plastic.

Thermal evaporation, known as vacuum metalizing, is the most common process used to apply metal alloys under vacuum pressure. This process have many applied to decorative bright chrome and metalllic finished, highly reflective coatings for light reflectors, heat shielding, vapor barriers and many others.

To do this process, many industrie build a custom tooling fixtures to hold mask parts during the vacuum metalizing and painting process done. For most decorative and reflective application it is necessary to apply a special formulated primer or basecoat to promote adhesion and to provide a smooth surface, assuring a high quality surface for the metalizing or finish paint steps.

All coating is applied by high volume low pressure spray guns by three different methods including, six axis robotic paint cells, automatic reciprocating paint cells, or by hand for low volume and prototypes.

Cylinder Coating

Cylinder can be coated by special electroplating tools. The current needed for this coating should be high enough in order can work coat to all the surface of cylinder block. Variety cylinder car engine block usually coated separately with other separate part that need of precise size like bore dimensions. To handle this special job, it should be experience in engineering and plating a wide range of surface and products.

Electroplating require apply in repair and maintenance of cylinder block and cylinder heads for variety of engines including motorcycles, dirt bikes, watercraft and race cars. Other part repair and maintenance that need electroplating finished work like in aerospace protection barriers, harness, corrosion prevention and decorative application. For cylinder block and cylinder head usually use chromium plating applied.

Electroplating Industry

The main problem on electroplating industries are how to control and prevent their waste that produce together with their product. Several components are dissolved on the solution and should be discharge because can’t use anymore as plating materials. The soluble material mostly include on hazardous waste and should be control in proper manner, or must use right waste treatment. Beside liquid waste this industries also produce solid waste and gas waste during the process running. All those kind of waste usually dangerous to human health. People who work on this industries should be protected by right and fulfill of health requirement. If there is deviation to this requirement it can lead of health disorder.

Pollution Control and Prevention
Plating industry may have different combinations of wide variety of processes and there are many ways to improve their prevention or pollution control. Some way that may apply to plating industry as follows:

Changes the Process

• Replace of cadmium substance with high quality corrosion resistant on zinc plating. Use cyanide free systems on zinc plating where appropriate. On cadmium plating can use bright chloride, high alkaline baths or other alternatives, but use complex agent of cyanides may cause problems in waste water treatment for they may result in the release of heavy metals.
• Use trivalent chrome instead of hexavalent chrome for chromium plating.
• Give preference to water based surface cleaning agent, where feasible, instead of organic cleaning agents, because of of those materials are considered toxic.

Reduction in Drag out and Wastage

• Minimize drag-out by affective draining of bath solutions from plated part by measures such as drain holes in bucket type.
• Allow dripping time of at least 10 to 20 seconds before rinsing
• Use fog spraying of parts while dripping
• Maintain the density, viscosity and temperature of the baths to minimize dragouts.

Many other ways can apply for environmental consideration, because plating industry have a big contribute to the pollution if not control in a proper ways.

Electroplating Equipments

One the most important on electroplating practice should use perfect electroplating equipments. If just use a conventional equipment, it very hard to get good plating result. Electroplating equipment should designed adapted prototype facilities to the parts size, result condition and chemical condition will be used on electroplating process.

There are some electroplating equipment for certain aim of products:

1. Mobile Coating Equipment
This tools are used to process or repair parts on site that need electroplating service. Electroplating equipment can be build on site and should be simple assembling.

2. Tools and Plant for Precision Plating
This equipment should able to serve an equipment with precision result, the product that need of precision plating such as shaft of hydraulic and other small part that will construct in other precision equipment. Highly product specific plating cells are needed for this service.

3. High Speed Plating
In order can produce electroplating product with high speed deposition, it is need an increase of current density. This equipment need a shifting point to move the product from plating bath and change with other new materials. High relative movement needed for this between electrode and cathode.

4. Selective Plating by Brush and Spot Plating
Selective plating outside the electrolyte is carried out by hand using the tampon process. To moving the material can use by automatic robot or by peoples.

Zinc Electroplating

Zinc electroplating is another process to make metal coated by zinc, this process is not made in big scale because more complex compared with other usual process done in industry like Zinc Immersion. For certain process that need special specification may use other kind process beside use zinc immersion. In industrial application this process more simple compare by zinc electroplating because can do in fast way and can apply to big steel depend on the bath available.

Zinc electroplating is a modified of zinc immersion to have zinc coated if that need more smooth on the surface and may need the result have evenly coating thickness. Zinc electroplating relatively low cost, protective nature and attractive appearance. The coating zinc done through this process gives corrosion protection to ferrous components and it can give color like gold, black or olive drab finish by post treatment.

Using zinc electroplating, we can coat nuts, bolts, washers and other kind parts for interior components and gas filters. Zinc electroplating solution use acid chloride, alkaline non cyanide and cyanide, and the most widely used zinc alloys for electroplating are zinc nickel cobalt and zinc iron. Even many metals can be plated by zinc but the common metal are steel or iron, on which the process offers sacrificial protection.

The process of zinc electroplating starting by alkaline detergent cleaning, and then treated with acid to remove rust or surface scales. The cleanliness is very important to prevent adhesion effect. The next process the zinc deposited on the metal by immersing it in chemical bath containing dissolved zinc. When a DC is applied, which result in zinc being deposited on the cathode, as like other kind of electroplating process use.