(b) Components with box sections, corners, crevices etc where normal paint spray cannot reach would be prone to corrosion. With the process explained in item no. 1 it is difficult to achieve salt spray hours of more than 300 hours even on simple components (which have easy access to reach paint spray). Hence, if you need corrosion protection for more than 300 hours on normal components or one needs to access the difficult areas of certain parts, then the solution seems to be electro-phorotech technology for depositing the primer paint using electrolysis method. This is followed by top coat of paint.

Typical components requiring electro-phorotech painting are automotive components, motorcycles, scooters, mopeds etc.

(d) Plastic Coating Lines -Several automotive parts like bumpers, mirror housing, car light housings, etc are coated in different colors to match the shade of the original car. Also cell phones, laptops, computer peripherals etc., are very popular to use special coating technology on plastic parts. There are different types of plastics and the choice of the painting process depends on end use requirements and the type of plastics.

Normally the processes followed are:

Manual wiping with a suitable chemical, or spray pre-treatment, de-static (de-ionising) process to remove the electrical charges on the part to control the dust levels, flaming with gas flame using a robot (with tracking facility in the conveyors) to increase the surface energy to facilitate paint adhesion, stabilizing zone before entering painting application booth. The painting process includes conductive primer, flash-off, base coat, flash-off, clear coat, flash-off, oven for paint drying, cooling etc. The most important aspect of the painting process is to maintain temperature and humidity level within the tolerance limit acceptable to the paint being used. Dust level control is another important aspect, as least amount of contamination is permitted.

In case of housings of the car lights, these are first applied with base coat, followed by aluminization and subsequent top coat/lacquer.

The paint circulation system is very critical to maintain the consistency of the paint finish quality. The design of the conveyor is normally ground mounted design with either skids on wheels with masts or skids mounted on triplex type of conveyor to ensure the parts swaying in front of the robotic paint applicator is well within close tolerance.

(f) Dip Varnishing Plant - The armature of the motors are generally pre-heated to 140 C before dipping into the varnish bath. After draining the varnish, the armatures are cured in an oven at 160 C, cooled and unloaded. The varnish bath is maintained at a specific temperature and continuous circulation is required for good quality coating deposition.

(g) Wood Coating Lines – typical wood coating lines use ground conveyor system, dust free clean room, dust free paint booths for applying poly-urethane paint, forced drying ovens, accurate paint mixing and circulating systems etc. Powder Coating or UV cured coating on MDF - is increasingly getting popular. But designing and controlling required complex process parameters making the project unviable in many cases.

(h) PVDF Painting - Architectural Aluminum profiles are generally powder coated for both indoor and outdoor applications. However to achieve longer life, 2 or 3 coats of PVDF painting can be done instead of powder coating on the passivated Aluminum surface. After the coating, it is baked once at a temperature of 250-260 C and this coating is getting popular despite the disadvantage of solvent borne pollutants.

(i) Shower Coating - Large size radiators and transformers with fins having longer depth will prevent the paint spray from entering between the fins. For this application, the shower coating with good paint circulation system followed by paint curing in an oven is an ideal process. This process is also followed for wood furniture coating as a primer coat.

(j) Applications of weldable primer - The standard steel plates are moved on a conveyor and shot blasted. Subsequently paint is applied automatically on both sides of the plates and force dried. These plates are then used for fabricating (parts of ships, rail engine etc) and subsequently for welding operation. The primer paint applied is weldable primer. Top coat is applied subsequently after fabrication and assembly.