» Elizabeth Norwood, Senior Chemist, MicroCare
For decades, benchtop or manual methods have been the go-to solution for PCBA cleaning processes. This approach relies on hands-on techniques such as scrubbing, rinsing, and wiping to remove contaminants from PCBAs using specialized cleaning fluids. While effective for small batches or non-critical applications, manual cleaning introduces notable challenges that modern electronics manufacturers must consider.
Challenges of benchtop cleaning
Contamination risks: If not performed correctly, benchtop cleaning is prone to leaving residual contaminants, such as flux, cleaning agents, or debris, on the PCBA. Despite the operator‘s best efforts, these contaminants can be difficult to remove fully, especially from intricate areas or hard-to-reach components. Contamination can lead to issues like corrosion, poor solderability, or dendrite growth, critical concerns for industries with high reliability demands.
Inconsistency: Benchtop cleaning is heavily reliant on operator skill. Variations in cleaning pressure, cleaning fluid application, or drying time can leave contaminants behind. This inconsistency can cause defects, performance issues, and reliability concerns, particularly in high-precision sectors like aerospace, medical, and automotive.
Labour-intensive: Cleaning each board manually is time-consuming and slows down production throughput, especially in larger-scale or more complex production environments. As manufacturing demands increase, this method becomes inefficient and costly, with longer lead times.
Limited effectiveness: Benchtop cleaning often struggles with intricate designs and small components, leaving contaminants in hard-to-reach areas. As PCBA designs grow more complex, the limitations of manual cleaning become clearer, necessitating a more automated and reliable solution.
Why vapour degreasing is better
Vapour degreasing is an automated cleaning method that uses solvent vapours to clean and remove contaminants from PCBAs, addressing the challenges of benchtop cleaning. It offers a range of benefits that make it a good solution for precision-driven industries:
Cleaning power: Vapour degreasing effectively removes contaminants such as flux, oils, and grease, even from difficult-to-reach areas. The vapours dissolve residues that would otherwise require manual scrubbing, ensuring a higher standard of cleanliness. The process ensures that even stubborn contaminants are removed, providing the level of cleanliness needed for industries with high reliability standards.
Consistency and repeatability: Unlike benchtop cleaning, vapour degreasing is an automated process, cutting the variability that comes with manual methods. The controlled environment of the vapour degreasing system ensures that the cleaning process is repeatable and consistent, with every cycle meeting stringent cleanliness standards. This level of consistency is crucial for cleaning complex and critical components, where even slight variations can compromise performance.
Enhanced efficiency and throughput: Vapour degreasing systems can clean multiple PCBAs simultaneously, greatly improving cleaning efficiency and throughput. This is particularly helpful for high-volume manufacturing environments where meeting tight deadlines is paramount. Manufacturers can manage larger batches faster, reducing lead times and improving production capacity.
Environmental and operator safety: Modern vapour degreasing systems are designed with environmental responsibility at their core. Features like fluid recovery and recycling, along with advanced filtration systems, help minimize waste and reduce the consumption of cleaning materials.
The cleaning fluids used in these systems have outstanding ecological and safety credentials. They are highly effective at thoroughly cleaning components and meet the stringent regulatory requirements of industries governed by international standards. Modern vapour degreasing fluids follow regulations, such as those set by the US EPA (Environmental Protection Agency) and the EU’s REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) framework. With zero Ozone Depleting Potential (ODP), low Volatile Organic Compounds (VOCs), and low Global Warming Potential (GWP), these fluids contribute to a safer and more sustainable cleaning process.
Moreover, these systems enhance operator safety by automating the cleaning process, minimizing direct human intervention and ensuring a safer working environment.
Cost-effectiveness: While the upfront investment in vapour degreasing systems may be higher than benchtop cleaning methods, the long-term benefits outweigh the initial cost. Vapour degreasing reduces labour costs, minimizes the likelihood of defects or rework, and increases throughput, ultimately improving overall operational efficiency. Manufacturers can see a clear return on investment through increased productivity and reduced waste.
Key considerations for adopting vapour degreasing
Before making the transition to vapour degreasing it is important to evaluate certain factors to ensure it meets your operational and financial goals:
Test data analysis: Review cleanliness testing results to assess improvements in residue removal and contamination levels compared to manual cleaning. Significant gains in these areas show vapour degreasing is a more effective solution.
Production requirements: Consider whether your production volume or the complexity of your PCBA cannot be met by manual cleaning capabilities. Vapour degreasing offers higher scalability and more reliable cleaning for high-demand environments.
Cost-efficiency assessment: Weigh the upfront investment in vapour degreasing against long-term savings from reduced defects, rework, and improved throughput. Consider hidden costs of manual cleaning, such as slower lead times and quality issues, to understand the return on investment.
Quality and compliance: Ensure vapour degreasing consistently meets or exceeds cleanliness levels and industry standards. This process helps you stay aligned with regulatory requirements and reduces compliance risks.
The role of cleanliness testing in the transition
Before transitioning from benchtop cleaning to vapour degreasing, it is important to evaluate the effectiveness of your current cleaning method through cleanliness testing. This evaluation ensures that manual cleaning does not leave behind residues or contaminants that could compromise the performance and reliability of PCBAs. Switching to vapour degreasing should be a well-considered decision, ensuring it aligns with your manufacturing needs and improves cleanliness and process efficiency.
Industry standards, such as IPC-TM-650 and J-STD-001, offer guidance for assessing the cleanliness of PCBAs and ensuring that cleaning processes meet specific quality requirements. These standards recommend testing residue levels, ionic contamination, and other critical cleanliness parameters for high-performance applications. By conducting these tests, manufacturers can gather data to verify that vapour degreasing meets or exceeds cleanliness standards, ensuring the transition is justified.
Various testing methods are commonly used to evaluate the effectiveness of cleaning processes:
Ion Chromatography (IC): This technique detects and quantifies ionic contaminants on PCBAs, such as flux residues, salts, or acids that may remain after manual cleaning. Ion chromatography can highlight whether manual cleaning has effectively removed these ionic contaminants or if vapour degreasing is needed to achieve the necessary cleanliness levels, ensuring the reliability and performance of the PCBA.
Surface energy analysis: This method assesses the cleanliness of PCBAs by analyzing the surface tension of the board. A low surface energy reading could show that contaminants are still present, even after cleaning.
Atomic Force Microscopy (AFM): AFM is a high-resolution imaging technique used to analyze the surfaces of PCBAs. It helps detect even the smallest residues or contaminants on a board. This method enables manufacturers to visually inspect and quantify the cleanliness of the surface at a microscopic level. By comparing the surfaces of PCBAs cleaned using manual methods with those processed via vapour degreasing, AFM provides insights into the effectiveness of each cleaning process in removing contaminants.
Taking the step
The transition from benchtop cleaning to vapour degreasing offers manufacturers a practical solution to meet modern PCBA quality requirements. While benchtop methods have served the industry for years, and still do in some cases, vapour degreasing provides the consistency and thoroughness needed for today‘s complex assemblies. The initial investment in vapour degreasing equipment typically pays off through improved reliability, reduced rework, and easier compliance with industry standards. By adopting this technology, manufacturers can enhance their production capabilities while supporting the cleanliness levels demanded by increasingly sensitive electronic components.
