As you may recall from our previous article, we conducted a detailed analysis of the painting process in automotive production facilities, covering every aspect of this process from the initial step of cathodic dip coating to the final quality control stage. In this article, we will delve into the painting processes in automotive production, particularly those involving overspray paint, where excess paint mixes with water to form paint sludge, and the filtration systems used in traditional paint booths.
First, let’s examine a traditional paint booth and how it operates. In traditional paint booths, the air used is typically 100% fresh air drawn from the atmosphere. Although systems have been modified recently to save energy, with recirculated overspray paint being filtered and returned to the paint booth, traditional paint booths are still widely used in the industry. In these booths, the air taken from the atmosphere is first passed through a coarse filter stage. Then, depending on the need, the air is conditioned using a dehumidification or heating/cooling unit to meet the desired operating conditions based on the location of the facility, the humidity, or the temperature of the air taken from the atmosphere. The conditioned air is then typically passed through a fine-grade filter before being sent to the paint booth. The air entering the paint booth passes through the final filter stage, known as the ceiling fiber filter, before reaching the painting environment. At the exit of the booth where the painting process takes place, a fan draws the air, along with excess sprayed paint, into the exhaust air ducts. During this process, the excess sprayed paint carried by the air is typically retained in a structure designed to capture a portion of the excess sprayed paint, known as a waterfall. The air releases the excess sprayed paint it carries into the water and is then discharged into the atmosphere through air ducts. This process continues as long as the painting process is ongoing.
In summary, air taken from the atmosphere is typically passed through three stages of filtration before being delivered to the paint booth, where it is used and subsequently released back into the atmosphere.
The three-stage filter levels are typically selected by paint facility manufacturers as G4-F7, followed by M5-level filters as ceiling fiber. These filter levels are widely accepted in the industry and are frequently chosen for production facilities.
Is the G4-F7 and M5 combination the correct combination for every paint booth?
The answer to this question cannot be given as a simple yes or no. To answer this question, we need to evaluate various parameters such as the location of the facility, the structure of the facility, the location of the facility, the particle density of the air taken from the atmosphere, the user’s quality standards, and the capacity of the fans used in the facility, and then select the optimal filter stage. At Mikropor, we assist our customers in determining the appropriate filter stages and filter types for their facilities.
How are the appropriate filter stages and types determined for a company?
First of all, when talking about filters, the most basic point for us is to filter particles. Here, we can define particles as contaminants that the user does not want. Although the values accepted by each company are similar, the values determined by the manufacturers according to their own standards are our starting point. For example, selecting the same filters for an environment where particles of 3 microns or larger are not desired and another environment where particles of 10 microns or larger are not desired typically results in unnecessary costs and energy consumption. Therefore, determining the size of unwanted particles is our starting point.
In the next step, the airflow rate that needs to be filtered, the capacities and characteristics of the fans used guide us in determining the details we need to consider when selecting filters.
After obtaining the data from the company, we begin field work and perform particle measurements. It is more accurate to perform particle measurements separately for each cabin. This is because even under the same roof, we may observe different particle types and loads in cabins facing different sides due to the air intake units. To provide a real-world example, we cannot expect the filter stages of a unit that draws air from a busy main road to be the same as those of a unit that draws air from a garden with trees and no traffic flow. For this reason, the particle load at each air intake point must be measured separately, and a particle map must be created. After measuring the particulate concentrations at the air inlets, alternative scenarios are simulated using the Life Cycle Cost analysis program developed by Mikropor to determine the optimal filter stages and the particulate concentration that will pass to the back side.
The Mikropor Life Cycle Cost (LCC) analysis is a filter selection program that compares filters used by businesses with filters that have a higher efficiency class, greater dust holding capacity, and lower energy consumption, calculates the filter costs incurred over the lifespan, and provides businesses with the optimal option for filter costs.
The data obtained from the analysis guides us in determining which filter stages should be selected. If the particle measurement and analysis program indicates a filter stage outside the G4-F7 classes, we compare this with technical data and share our recommendation with the users. At this point, businesses are somewhat hesitant to try a different combination from the ones they have used before. The reason for this is that even the smallest change in a system producing 1,200 vehicles per day could result in significant losses. At this point, our 38 years of experience and the fact that we supply products to the most important automotive manufacturers in Turkey and around the world, as well as testing our filters under real-world conditions in various facilities with different operating conditions, provide a significant advantage in anticipating the potential negative outcomes of changes to the system and guiding companies toward the correct selection based on experience.
Filter efficiency classes are typically determined by particle measurement and the company’s production standards. It is more accurate to say “typically” because some companies prefer to proceed with the filter efficiency classes provided by the facility designer to avoid taking risks. In such cases, even if we do not change the efficiency class, we work to provide the optimal solution by changing the filter types to achieve the desired efficiency class.
When making new filter recommendations, the distances between the units where the filters will be installed are another selection criterion that limits our filter selection. With Micropor, we are able to overcome these limitations with our different products. For example, in a facility where G4 panel filters were initially used, if we need to proceed with G4 filters at the same stage, we can offer an alternative solution using our G4 bag filters to extend the service life and reduce the replacement interval. In this case, our choice could be the MPR Series G4 bag filter. With this filter, we can offer a solution with a pocket depth suitable for the filter’s location. Additionally, for units where there is no space at the back, we can provide an alternative with our MPR Reverse Series G4 bag filter, which is designed with the pockets at the front and operates under reverse airflow. All these solutions depend on the company’s conditions and may vary for each stage. For example, even if the company is using a V filter, or even our MV Series filter, we can suggest improvements with our MVEE Series products, which offer a larger surface area, lower initial pressure drop, and longer service life under the same conditions.
In another scenario, we encounter situations where an additional filter stage is required due to the existing G4-F7 combination failing to reduce the particle load to the desired level. In such cases, Mikropor offers a wide range of alternatives. We can produce alternatives by combining our clip-to-clip filters, MVC Series products, or MPR Reverse Series with a second filter to be used in combination with the filter housing where the filter will be installed. With these methods, we offer alternative solutions by replacing an existing filter with two different filters of varying efficiency that can be installed in the same housing.
Although filters are generally considered consumables, they are among the primary elements that can prevent or reduce quality issues encountered in automotive production. While many companies accept an average dust level of 8-12 per vehicle, reducing higher average dust levels to these levels can be achieved by simply reviewing filter selections and properly implementing filter usage processes, potentially without incurring additional costs. In a facility producing 1,200 vehicles daily, even a one-unit reduction in dust per vehicle would represent a significant improvement.
Small changes can sometimes lead to big problems. However, if you know what you are doing and how to do it, small changes can often result in significant gains rather than causing issues. With over 38 years of experience in filtration, Mikropor (+ ) has always been a company that produces alternative solutions and leads innovation in the industry. With the experience we have gained in paint plants, we can offer you benefits in terms of quality, cost, and energy savings through small changes we can make in your operations. Feel free to contact us to see our alternative solutions.
