How We Solved Foaming Issues in Automotive Industry Washing Lines: A Step-by-Step Practical Solution

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In the automotive industry, washing lines receive exceptional attention – the cleanliness of components directly impacts the quality of subsequent painting and assembly. However, excessive foaming can disrupt the entire process: foam reduces washing efficiency, clogs filters, and in extreme cases, causes bath overflow. In one of our cases, a customer faced repeated production downtimes due to foaming that could not be eliminated with conventional methods. Analysis revealed that the cause lay in a combination of unsuitable surfactants, temperature conditions, and mechanical stress. The solution required not only a change of raw materials but also adjustments to technological parameters.

Foaming in washing lines: How it occurs and why it is dangerous

Foaming in automotive industry washing lines is a frequent but underestimated problem that can significantly disrupt the production process. It primarily occurs when unsuitable surfactants are used or their concentration is excessive, leading to the formation of a stable foam layer on the surface of washing baths. This foam hinders the effective removal of dirt, reduces rinsing efficiency, and can result in insufficient degreasing of metal parts. In extreme cases, foam overflow from washing tanks occurs, increasing the risk of accidents and workplace contamination.

Additional factors contributing to foaming include the high temperature of washing solutions (usually above 60 °C), mechanical agitation, or the presence of organic contaminants such as oils and greases. Foam also impairs heat transfer and increases energy consumption, which directly impacts operating costs. For manufacturers, it is crucial to identify the cause of foaming as soon as possible to avoid downtime and unnecessary costs for repairs or replacement of chemicals.

Root Cause Analysis: How We Identified the Source of the Problem

The first step toward a solution was a detailed mapping of the washing process and an analysis of the chemical mixtures used. In this case, we found that the client was using a combination of anionic and nonionic surfactants, which are effective for degreasing but, when mixed in incorrect ratios or concentrations, exhibit a strong tendency to foam. Laboratory tests showed that foam formation occurred particularly at elevated temperatures and under mechanical stress, which corresponded to the conditions in the washing lines.

We also conducted a water quality analysis, which revealed a high content of dissolved minerals, particularly calcium and magnesium. These ions react with surfactants to form insoluble complexes that stabilize foam and hinder its breakdown. Based on these findings, we recommended adjusting the detergent formulation and optimizing process parameters such as temperature and washing time to minimize the risk of foaming.

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Practical solution: Adjusting the formulation and process parameters

Based on the analysis, we proposed several specific measures. The first step was adjusting the surfactant ratio in favor of low-foaming nonionic types, which are less sensitive to water hardness and mechanical stress. We also recommended reducing the concentration of anionic surfactants by 20–30 %, which significantly limited foam formation without losing cleaning efficiency. To stabilize the foam, we added small amounts of silicone- or mineral oil-based defoaming additives, which act preventively.

In addition to modifying the chemical composition, we also optimized the operational parameters of the washing lines. Reducing the temperature of the washing baths from 70 °C to 55–60 °C reduced foam formation by over 40 %, while cleaning efficiency remained unchanged. We also adjusted the airflow in the washing chambers to minimize mechanical mixing of the solution. These changes were implemented gradually, and their effectiveness was continuously monitored using standard test methods.

Results and Long-Term Benefits for the Customer

After implementing the proposed measures, there was an immediate improvement in operating conditions. Foam formation was reduced to a minimum, enabling smoother operation of the washing lines and eliminating the risk of overflow. The client recorded a 15–20 % reduction in detergent consumption, as the new formulation required a lower concentration of active substances. At the same time, the washing time was shortened, leading to energy savings and increased productivity.

Long-term benefits also became apparent, such as reduced equipment wear due to lower mechanical stress and improved quality of surface treatment of parts. The client also appreciated the reduced environmental impact, as the new formulation meets biodegradability requirements under REACH and CLP regulations. This case demonstrates how important collaboration between a chemical raw material supplier and a manufacturing company is in solving operational problems to achieve optimal results.

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Selecting Suitable Low-Foaming Surfactants: The Key to Effective Solutions

When addressing excessive foaming in automotive industry washing lines, selecting the right surfactants is crucial. Standard anionic surfactants, often used for their high cleaning efficiency, tend to create stable foam, especially during mechanical agitation or at high temperatures. For industrial applications where foaming is undesirable, low-foaming alternatives such as nonionic surfactants based on alkoxylated alcohols or special block copolymers have proven effective.

These substances reduce the surface tension of water similarly to conventional surfactants, but their molecular structure prevents the formation of stable foam. When selecting them, it is important to consider not only foaming properties but also compatibility with other components of cleaning agents, such as corrosion inhibitors or chelating agents. Testing under laboratory conditions according to standard methods helps verify whether the new formulation achieves the desired cleaning efficiency without unwanted foaming.

Optimising Process Parameters: Temperature, Concentration, and Mechanical Influences

In addition to adjusting the chemical composition, it is essential to optimise the operating conditions of washing lines. The temperature of the working solution has a significant impact on foaming – higher temperatures generally reduce the viscosity of the liquid and accelerate foam breakdown, but for some surfactants, the opposite effect may occur. In practice, maintaining a temperature range of 40–60 °C has proven effective, where most low-foaming systems perform optimally.

Another critical factor is the concentration of cleaning agents. An excessively high dose increases the risk of foaming, while insufficient concentration may reduce cleaning efficiency. Regular conductivity measurements or refractometric checks are recommended to maintain a constant concentration. Mechanical factors, such as nozzle pressure or conveyor speed, should be set to minimize turbulence, which promotes foaming. Automated dosing systems and solution quality sensors can help keep the process stable.

Monitoring and Preventive Maintenance: How to Prevent Problem Recurrence

A long-term solution to the foaming problem requires systematic monitoring and preventive maintenance of washing lines. Regular checks of the working solution's quality, including pH measurement, water hardness, and residual surfactant content, allow for early detection of deviations from optimal conditions. The water used in washing lines should be analyzed for mineral content that may affect foaming, such as calcium and magnesium.

Preventive maintenance also includes cleaning nozzles, filters, and tanks, where residues or biological deposits may accumulate, impairing the effectiveness of cleaning agents. Training operators on proper dosing and maintenance procedures is as important as the technical solution. Implementing standardized operating procedures and maintenance records helps keep the process under control and minimizes the risk of foaming recurrence.

Need to Optimize Your Cleaning Processes?

Every application requires an individual approach – from selecting the right surfactants to adhering to technological parameters. GCG Group provides detailed technical data sheets and safety data sheets (SDS) for supplied raw materials, including recommendations for specific applications. Our experts will help you with the selection and process setup to ensure it is stable and efficient. Contact us – or browse our catalog of over 1,300 products right away.