The Crucial Pre-treatment Process

The pretreatment process in essential in every paint finishing system. The final coating quality depends to a great extent on the quality and design of the pretreatment.

After having design painting lines for a wide variety of products everything from large metal and plastic parts to small covers seals we know which pretreatment process is necessary to obtain the product finish that you require.

Spray Pretreatment:

For metal and plastic parts that cannot be dip-coated and have repetitive components and large volumes, pass-through spray pre-treatment systems or chamber pretreatments are built. 

This system for online cleaning of consists of a tunnel mounted on tanks, components piping pump and nozzles etc. Pre-treatment in spray lines are done by spraying chemicals on to products with the help of spray nozzles.. Pressurized spraying of chemicals ensures that the parts are coated and washed.  

Particular attention is paid to optimizing water and power consumption. This significantly reduces the costs for fresh water, waste water treatment and production. 

Dip Pretreatment

The dip pretreatment systems have been designed to keep the cost low. The heating systems and the oil skimmer help further this objective. In conveyorized dip pretreatment plants, articles/components are hanged on a conveyor and are dipped into the tanks. In this operation, the articles / components travel through a  tanks.

Transporter type Pretreatment

This type of plant is being offered typically for the customers who have variety of components being handled or geometry of the components does not allow them to go with spray Pre-treatment plant.

This type of plant is very simple in nature. It uses PLC controlled transporters for automatic  process control. The movement of component is vertical for every dip type process stage and horizontal between two process stages. Multiple wagons are used to meet the required process and cycle times. The system is fully automatic removing manual intervention and increasing the productivity and efficiency.

Depending on the chemical supplier, the numbers of process/tanks are decided. 

Everyone component has different needs and expectations when it comes to aesthetics and coating life, and bare metal isn’t quite right for the intended purpose. When left unprotected, the iron in metals reacts with oxygen to form rust. This means that colorful exteriors aren’t just decorative—they are functional barriers that prevent corrosion. 

Metal parts can be finished with either wet painting or powder coating. 

Pretreatment is identical in both processes. Before any coating can be applied, the surface needs a thorough cleaning. Any oil, dirt, moisture, or other contamination will interfere with surface adhesion.

Both coatings contain resins, additives, and pigments. The major distinction is solvent: wet paint contains solvent, but powder coating doesn’t.

The design of a painting line can range from being fully manual with both the transportation from one process to another and the paint application being handled manually to a semiautomatic or full automatic painting line, where the transportation and/or application is automated.

Cathodic Electro-Deposition

A perfect primer is the basis for a consistent paint structure. For metal components in particular, cathodic dip painting is a particularly economical option. Mass-produced goods with high quantities, heavy welded constructions for construction machinery or entire bus bodies – depending on the throughput and weight or size of the components, the dipping can be carried out continuously in a pass or discontinuously in a cycle

Conventional Painting

Conventional wet painting involves spraying paint that requires a solvent to keep it in its liquid form. Once applied, most surfaces need anywhere from a few minutes with curing ovens to cure depending on the paint and drying/curing temperature.

Powder Coating 

Powder coating uses an electrostatic gun to apply a positive charge to the powder sprayed on a negatively charged part surface. A unique benefit of the charged powder application is that the positive charge will repel excess powder, preventing it from being applied too thick followed by baking/curing based on powder chemistry.

Paint Application

A manual painting line is suitable when flexibility is crucial, e.g. when painting large, complex items or items of varying sizes and shapes. With many color changes, a manual paint application can also be the best solution.

If there is a need for a painting line with large capacity, a full-automatic painting line is the best way to ensure an efficient and reliable painting process. In a fully automatic painting plant, the items are transported automatically from one process zone to another either on overhead conveyor, floor-mounted conveyor, power and free-conveyor or roller conveyor, and the paint application is performed by use of robots.

In other situations, a semi-automatic line with manual handling of some of the processes can be the best solution.

Dry and cure ovens are used at different stages in the painting process to dry the items and cure the painting. Ovens are generally the last stage of any coating process. Convection ovens or infrared (IR) radiation ovens can be used for the drying or curing process. The design of the ovens are adapted to the material-specific curing characteristics. 

Convection Oven 

DAS dryers are able to achieve optimum efficiency through targeted airflow. In addition, they can be divided into several heating and holding zones. Combination of effective insulation and advanced technique ensures energy efficient, cost-effective drying, hardening and curing solutions.

Infrared Oven

An infrared oven uses infrared radiation rather than convection heating to cure or bake part. Rapid heating and uniform temperature distribution can be individually adapted to suit the workpiece geometry. The focus is on short process times and high throughput rates with consistently high quality.

The conveyor system in the painting factory is an automatic transportation system that is involved in the entire process from receiving the part from the welding factory, passing through the painting process, and handing over the car body to the assembly factory.

Overhead Conveyors

An overhead conveyor is a conveyor system that uses roof space instead of floor, above or over the head of working area for the transportation of materials from one place to another. Flexibility of changing direction both horizontally and vertically. Overhead Conveyors are easy to install and consumes less amount of power as compared to other material conveying system in use. Industrial overhead conveyor systems are very helpful for painting parts and powder coating automotive industries.

Floor Conveyors

The part is mounted directly on the skid and can be stacked or disassembled in an empty state. We can also provide lifting equipment and transfer equipment required for the system. It is also possible to improve space efficiency by stacking empty skids. Floor conveyor is generally used in the top coating.