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How to Clean PCB?

When diagnosing issues related to the inoperability or suboptimal performance of a circuit, engineers frequently employ simulations and other analytical tools to assess the circuit’s schematic intricacies. However, in instances where these techniques fail to rectify the problem, proficient engineers may encounter a state of perplexity, frustration, or impasse. To preempt analogous conundrums, FS Technology presents a fundamental yet highly significant recommendation: the implementation of PCB cleaning. This practice serves to mitigate potential problems arising from contamination, impurities, or accretion, thus contributing to the systematic troubleshooting process.

Significance of PCB Cleaning Process

The undeniable importance of cleanliness is not merely a reflection of maternal emphasis, but rather a critical consideration in its own right. Evidently, a printed circuit board can be susceptible to various forms of impurities, including greases, oxidation of exposed metal surfaces, and residues stemming from the manufacturing process. These cumulative factors collectively contribute to potential common PCB problems. Before we begin soldering, let’s take a closer look at the effects that contamination can have on the PCB board.

Oxidized PBC Board
Figure 1: Example of a contaminated PCB before soldering process.

Electrical Reliability

Notably, the presence of fingerprints on the PCB substrate introduces the inclusion of salts, which can potentially exert an adverse influence on the soldering process, especially when prolonged contact with metallized areas coincides with a humid environment. Contamination, if present, has the potential to disseminate to regions hitherto untouched by the flux or its accompanying solvent. These blemishes possess the capacity to engender subsequent concerns pertaining to the electrical reliability of the operational PCB or to undermine the adherence and overall efficacy of any ensuing post-soldering protective coatings.

Consequently, FS Technology underscores the recommendation to incorporate a systematic circuit board cleaning procedure within the PCB assembly processes. This proactive measure serves to preempt the emergence of latent failure-related predicaments.

Circuit Board Aesthetics

For esteemed brand entities such as FS Technology, the pursuit of excellence encompasses not only the provision of superior-grade circuit boards, punctual order fulfillment, and unwavering professionalism but also extends to the realm of meticulous PCB cleaning systems aimed at preserving the aesthetic refinement of boards. This endeavor serves to bestow upon customers a gratifying visual encounter, thereby enriching their overall engagement. Upon receipt of the merchandise, the inadvertent presence of oil blemishes or residual matter on the board surface can potentially cast doubts upon our organizational prowess. Additionally, the occurrence of pale regions surrounding solder joints has the propensity to inadvertently evoke unwarranted perceptions of imperfections, leading to avoidable misconceptions and heightened scrutiny during the inspection process.

PCB Cleaning Kit Required for Procedure

Here are some kits that need to be used for cleaning, some are necessary and some are optional. While it is acknowledged that certain budget-conscious small-scale workshops might forgo this procedural facet in an effort to curtail expenses, the attainment of customer endorsement necessitates a comprehensive array of circuit board cleaning implements. In catering to novices, the judicious selection of an appropriate tool is contingent upon a thorough assimilation of the product specifications and prevailing circuitry conditions.

PCB Cleaning Brush

Brushes for cleaning PCBs
Figure 2: Brush being used to clean PCB before soldering

For expedited cleaning of expansive surfaces, a banister brush proves to be a commendable option. However, in scenarios demanding meticulous precision, the utilization of cost-effective tin brushes procured from hardware establishments offers a viable solution. It is imperative to exercise discretion in favor of a fiberglass bristle PCB cleaning brush, eschewing its hard-bristle counterparts to safeguard circuit integrity during the cleaning process. While attending to PCB cleaning, adept maneuvering of the brush bristles at an angle facilitates access to diminutive spaces, enabling judicious application of the cleansing solvent within the more inaccessible recesses of the board. These compact brushes exhibit exceptional efficacy in navigating confined areas inherent to circuit boards.

Lint-Free Towels or Microfiber Cloths

Towels for cleaning PCBs
Figure 3: Microfiber cloth being used to clean pre-soldering area of PCB

After the PCB washing process is completed, it is imperative to employ a lint-free towel or microfiber cloth for the purpose of meticulously eliminating residual detergent solution from the circuit board’s surface. This precautionary measure serves to mitigate the potential onset of chemical corrosion stemming from prolonged exposure. The chosen materials, whether lint-free towels or microfiber cloths, are expressly selected to curtail the propensity for introducing extraneous particulate matter, such as dust or other minuscule particles, into the apparatus.

Alcoholic Solvents

clean pcb with alcohol
Figure 4: Different alcoholic solvents used for removing moisture from PCBs

Uncontrolled ambient conditions can potentially result in the accumulation of moisture within PCB, instigating the commencement of the corrosion cascade. In numerous instances, this corrosion phenomenon stands as the primary instigator of circuit board shorts. To address this inherent moisture concern, the employment of clean PCB with alcohol emerges as a viable solution. The alcohol-based solvent interacts with water, engendering a solution that subsequently undergoes evaporation, concomitantly expelling the water content. This method’s efficacy is underpinned by its profound capacity to rectify corrosion-related impairment induced by moisture, thereby forestalling the propagation of further deleterious effects.

Compressed Air

Compressed Air Cleans PCB Dust
Figure 5: Compressed Air Jet to remove debris from PCB

This phase constitutes an integral component of the pre-soldering and cleansing regimen. Compressed air offers a discreet and effective mechanism to dislodge any accumulated particulate matter that may have settled upon the surfaces of the PCB or lodged within their intricate via holes. Notably, a common practice among electronics enthusiasts involves employing their breath to displace residual dust from the board’s exterior, a course of action that is not recommended. This caveat arises from the potential amalgamation of water vapor present in the breath with dust particles, resulting in adherent residues that are arduous to expunge. To circumvent this predicament, the utilization of compressed air facilitates the precise release of short, controlled bursts of air through the designated vents, thereby achieving comprehensive cleansing while preserving the PCB’s integrity.

Etching Resistant Chemical

best pcb cleaner: Etching Resistant Chemical
Figure 6:Blue coloured etching resistant chemical

The etching process represents a prevalent technique employed in the fabrication of PCB. This methodology entails the use of potent acidic or alkaline etching solutions, the improper cleansing of which can engender PCB contamination. In order to effectually eliminate these chemical residues from the PCB, a range of anti-etching solvents are judiciously employed, contingent upon the specific etchant utilized within the etching process.

Ultrasonic PCB Cleaner

In large-scale PCB assembly orders, manufacturers often need to handle over 10,000+ boards. Pure manual cleaning is not efficient and can slow down project progress. To address this, ultrasonic PCB cleaner is commonly employed. Many users worry that immersing circuit boards in a water solution could be detrimental, but this concern is largely unnecessary. FS Tech frequently adopts this method in mass production, ensuring it is harmless to the circuit boards and other electronic components. This process helps thoroughly and effectively remove contaminants like flux, solder paste, ink markings, fingerprint oil, and other potential sources of corrosion.

Best Way to Clean PCB Board

Realize the PCB cleaning process step by step

  1. Prior to initiating the cleaning process for the assembled PCBA board, it is imperative to ensure the removal of PCBA connectors and, if deemed necessary, to desolder PCB components.
  2. Thoroughly inspect the components and scrutinize the quality of welds, promptly effecting replacements or repairs to rectify any identified defects.
  3. Commence the cleaning procedure by positioning the PCB within a well-illuminated environment, thereby facilitating the discernment of contaminants and ensuring comprehensive coverage across the PCB surface.
  4. Gradually rinse the PCB surface with water; should alternative cleaning agents be utilized, a secondary cleansing step becomes requisite.
  5. Employ a directed stream of compressed air to dislodge conspicuous macroscopic debris from the PCB surface.
  6. Initiate the cleaning phase utilizing an alcohol-based solution, applying a soft-bristle brush to meticulously address all sections of the PCB, with particular emphasis on areas displaying corrosion. Allow a brief interval for the solution to interact before progressing further.
  7. Subsequent to the application of the cleaning solution, delicately employ a lint-free or microfiber towel for patting, diligently avoiding wiping motions to avert potential abrasion or scratching.
  8. Conclude the process by once again utilizing compressed air to eradicate any residual remnants.
  9. Upon thorough completion of the aforementioned steps, judiciously administer an etching-resistant chemical, paying close attention to the soldering pad domains, thereby culminating the PCB cleaning solution.

Precautions for cleaning PCB board

  • Exercise meticulous caution while utilizing brushes, towels, or microfiber cloths to safeguard sensitive sections of the PCB, including delicate wire tracks, from inadvertent damage.
  • During the application of an ultrasonic cleaner for PCB cleaning, ensure the secure placement of the circuit board within a fixture to avert potential component impairment arising from vibrational forces.
  • When undertaking the cleaning of component footprints on PCB, it is paramount to possess access to the most current datasheets and pertinent component information. This proactive approach aids in the avoidance of deploying chemicals that could compromise the integrity of component placement terminals.
  • In light of the fact that flux residue progressively solidifies over time, giving rise to corrosive byproducts such as halogen salts, immediate post-soldering cleaning of the assembled PCBA board is imperative.
  • PCBA manufacturers are advised to institute standardized cleaning protocols, including the utilization of masks and electrostatic wristbands to mitigate potential contamination risks.
  • Following the cleaning process, conduct a thorough assessment of the board’s cleanliness to ascertain conformity with established PCB cleaning standards, thereby preempting the presence of impurities such as residual flux, tin beads, and tin slag.
  • Subsequent to cleaning, exercise prudence in the drying phase, refraining from subjecting the circuit to excessively elevated temperatures that may engender circuit damage. Generally, oven temperature should be maintained within the range of 30 °C to 40 °C.
  • Distinguish between cleaned and uncleared PCB, refraining from direct manual contact with the board surface to preserve its integrity and cleanliness.

PCB Cleaning FAQ

As a turnkey PCB assembly company, FS Technology does not provide separate cleaning services, but incorporates them into the production process as part of quality control. If you need electronics manufacturing services, we are happy to help.

The solvents that can be used to clean PCB surfaces include water, isopropyl alcohol, ethanol, deionized water, cleaning agents, environmentally friendly solvents, and ultrasonic cleaning solutions, etc. When making a choice, considerations should focus on the type of contaminants and material compatibility, which will be provided with necessary prompts during your purchase.

A multitude of PCBA companies are in operation, with some being of high quality while others are deemed unreliable. Ensuring that your PCB assembly service includes a cleaning process is an effective measure to avoid dealing with unscrupulous vendors.

Most PCBA projects only need to meet the cleanliness requirements and guidelines outlined in IPC-5704 and IPC-6012D. However, if your project involves medical or military applications, additional criteria may be necessary.

This is a potentially misleading issue. Tap water should not be used to rinse circuit boards. It is emphasized here to use distilled water, and contact should be made with materials like cotton swabs rather than direct rinsing.

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