Paint Booth Design
The spray booth provides a safe, clean painting environment for a better quality finish and increased productivity.
The needs of the application — what is being painted, how it is being painted and what coatings are being applied — determine the paint booth design. Objects from small parts to large trucks are painted in spray booths, and the coatings can be applied by both humans and robots. Regardless of the application, careful matching of the equipment to the needs of the coating operation is critical to the successful performance of the spray finishing equipment and the quality of the application.
Knowledge about the facility and production process is important in choosing the right equipment. It is important to understand the application and any future plans that may influence the choice of spray booth design.
Selecting the Spray Booth Design
The first steps in selecting an appropriate paint booth design begin with identifying your budget, production requirements, as well as building accessibility and constraints.
Know Your Budget
Balancing the application requirements and available funds will help identify the most effective exhaust chamber, airflow and paint booth options for the job.
Application Requirements & Configuration
The size and style of the vehicle or part, how it moves into and through the spray booth, and the proximity of the spray gun to the vehicle or part all play a role in determining the direction, velocity and speed of airflow through the spray booth. Airflow is needed to capture paint and coating overspray in the filter assembly.
Production rate is a measure of the number of vehicles and/or parts that can be finished within a certain time frame — usually per hour, shift or day. Production rate includes the entire production process, including any time the vehicle and/or part spends drying or curing.
Material Being Sprayed
The type of paint or coating being sprayed affects the choice of filtration or exhaust method to remove overspray from the paint booth, and determines whether or not heat or other curing methods are required. If more than one type of paint or coating is being sprayed, it is important to ensure the compatibility of the materials. Combinations of incompatible materials in the dry filter can be a cause of spontaneous combustion.
A dry filter or paint arrestor spray booth traps airborne paint particles (overspray) in disposable filters. A dry filter paint booth can be used where material usage does not exceed 2 gallons per hour with minimal overspray. This represents the majority of applications. Depending on the coating, removal efficiency ranges from 95 to 99 percent.
In a water wash booth, air washing action traps paint solids from overspray. Removal efficiency for a water wash booth can be as high as 98 to 99 percent, depending on the type of material being sprayed.
If the coating material requires a period of heat or air movement to dry or cure it, heaters and other curing methods must be part of your finishing process.
The quality of the finish has become more critical as customers’ expectation levels have increased. The total process must now be considered in order to achieve the appropriate quality levels.
Spray booth design is a key element. Airflow direction, filtration, velocity and balance are critical to accomplishing the desired quality level. A pressurized downdraft paint booth typically produces the highest quality paint finishes for automotive applications, whereas a non-pressurized crossflow spray booth has the lowest potential for a high-quality paint job.
It is also important to recognize the spray booth is only one part of the process. Many other elements of the process must be designed and controlled to achieve the desired quality level. Other equally important elements include:
- Preparation and cleanliness of the object going into the paint booth
- Maintenance of the spray booth
- Quality of compressed air to the tools (including the spray gun)
- Proper painter protection, including suit, hood and gloves
- Quality of the paint or coating preparation
The paint finish quality can only be as good as the design and control of the entire finishing process.