The Indian Electronics Industry today stands at US$ 25 billion (र125,000 crores approximately). According to a study by the Export-Import Bank of India (Exim Bank), it is estimated to exceed $150 billion (र750,000 crores approximately) by 2015 and is growing at a Compounded Annual Growth Rate (CAGR) of over 25%. Exports of electronic goods are expected to touch $15 billion (र75,000 crores approximately) by 2013-14, an estimate by the Ministry of Commerce and Industry. It is growing in sectors like commercial software, telecommunications, electronics, instrumentation, positioning & networking systems, Consumer Electronics and Industrial Electronics.
The industrial cleaning requirement is therefore projected to grow complemented with advancements in cleaning technologies like Ultrasonic Cleaning, High Pressure Cleaning, Aquastorm, Plasma and Water based Surfactant Technology.
The purpose of cleaning, specifically within the rapidly expanding electronics industry, is to essentially improve product lifetime, increase the reliability of assemblies and allow coating and encapsulating operations to be carried out efficiently. More so as cleaning is still an essential multistage process within the electronics industry. Says Nanjunda Swami, Production Manager, Easun Reyrolle Ltd, Bangalore, a company into electronic fault finding, conformal coating removal and diagnostic testing for complex electronic systems, “All our electronics components and Printed Circuit Boards (PCBs) cleaning are done through Ultrasonic Cleaning at the sub contractor’s end before soldering and after soldering. Another stage of ant- static or anti-tarnish cleaning by liquids is done inside the manufacturing unit for PCBs.”
He further explains that Ultrasonic cleaning is used for cleaning of PCBs after the soldering process in the Electronics industry. Although many chemicals are available, no-clean flux is used for better results. The cleaning process depends on the quantity which is why manual brushing is used if the quantity is small but the cleaning solution remains the same. These are tailor-made solutions and no detergents are used. High pressure cleaning is used in the assembly area, while vacuum cleaner is used to avoid dust in the room.
Besides, Easun Reyrolle Ltd is also using automatic compressor systems for varnishing. Nanjunda explains, “The electronic components are varnished so that components does not get tarnished by humidity and other environmental conditions.
“Chemicals are available in the market as anti-tarnish PCBs conformal coatings with acrylic or silicon base. Kaiser Fluids Inc. is the manufacturer and exporter of anti-static cleaning in Electronics industry.”
Water based Surfactant Technology is also in use in the industry for heavy contaminants, which are removed by detergents and water with the help of this technology.
Cleaning – a multi-stage process
There are many stages where cleaning is required; prior to stencilling and soldering in order to remove contaminants from the many previous production stages; after stencilling to remove excess adhesive, and after soldering to remove corrosive flux residues and any excess solder paste.
Such residues, along with any other unwanted elements collected due to the missing cleaning stage, could cause issues with adhesion and possibly affect the performance of the protecting media applied.
Trends in cleaning
There are many applications for cleaning, all of which depend on the type of equipment available. Whether it be ultrasonic, spray under immersion or dishwasher type application, identifying the correct water-based cleaner for a specific job is essential. Says Laxmikant, Production Manager, Innovlite India Pvt Ltd, Bangalore, “Ultrasonic cleaning is applicable in most large scale units of the electronics industry.”
There are, however, technologies which do not complement Ultrasonic Cleaning. Hemanth Bapat, DGM, Manufacturing, BPL Techno Vision Pvt Ltd, “Surface Mount Technology is used in our manufacturing facility, in which the components are mounted directly onto the surface of PCBs through Reflow Soldering. Electronic components get soldered without leaving any trace of flux. There is, therefore, no requirement left for Ultrasonic Cleaning or any cleaning after the soldering.”
Raghu, Production Manager, Avalon Technologies Pvt Ltd (Sienna Corporation), Chennai, said Aquastorm is a versatile, high-performance cleaning system designed to optimize the PCB cleaning process while minimizing overall cost. This cleaning is used for the water soluble process. It looks like a lengthy oven and has three or two wash chambers depending on the requirement.
Ultrasonic Cleaning is the other type of cleaning applicable for the PCBAs to remove the residues. These are available in different frequency ranges and the normal cleaning agent for this is the Isoproponal Alcohol (electronic grade).
Cleaning Audit
PCBs are subjected to thorough inspection by Automated Optical Inspection (AOI). This is to check excess Lead in the soldering area or dry soldering. Floor mats are checked to ensure anti-static properties through the meters.
There are two main categories of cleaner currently available, solvent based and water based. Traditionally, solvent based cleaners such as 1,1,1-trichloroethane and 1,1,3- trichlorotrifluoroethane dominated the market; however, due to their ozone depleting potential, they have been replaced by a more diverse range of solvent cleaners. This category is now typically divided into three sub-sections; flammable solvent cleaners, non-flammable solvent cleaners and non-flammable halogenated solvent cleaners such as HFCs and HFEs. All three types have their advantages and disadvantages but overall solvent cleaners can be described as fast evaporating, single stage cleaners. However, they require specialist equipment and extraction to protect against toxicity and other possible hazards.
Laxmikant said, “Cleaning of the PCBs is done manually by alcohol IPA in our units. Flux contaminants and regular rosin flux is removed using Industrial Grade IPA. Hygiene and cleanliness of the factory is maintained through regular mopping.”
Founded in 2005, Innovlite is one of India’s Green Business pioneers with a track record in technology-based innovation that contributes to a clean and healthy environment.
