What are the taboos for using industrial washing equipment?

As electronic products evolve toward miniaturization and higher density, the cleanliness requirements for PCBs (Printed Circuit Boards) and various precision components have become increasingly stringent. Industrial cleaning equipment plays a critical role in removing solder residues, oils, dust, and other contaminants. However, improper operation can lead to damaged components at best, or complete batch product scrappage at worst. This article systematically outlines the core taboos in using industrial cleaning equipment for PCBs and precision components, serving as a reference for relevant enterprises and operators.

As electronic products evolve toward miniaturization and higher density, the cleanliness requirements for PCBs (Printed Circuit Boards) and various precision components have become increasingly stringent. Industrial cleaning equipment plays a critical role in removing solder residues, oils, dust, and other contaminants. However, improper operation can lead to damaged components at best, or complete batch product scrappage at worst. This article systematically outlines the core taboos in using industrial cleaning equipment for PCBs and precision components, serving as a reference for relevant enterprises and operators.

I. Chemical Cleaning Agent Selection Taboos: Corrosion and Short Circuits Are Two Major Danger Zones
Taboo 1: Do Not Use Ordinary Water-Based or Alkaline Cleaning Agents

Ordinary water-based or alkaline cleaning agents have excessively high pH levels, which can corrode component packaging on PCB boards, cause circuit short circuits, and even damage metal coatings on precision parts. For circuit boards containing sensitive components such as aluminum electrolytic capacitors or silver solder pads, cleaning agents containing sulfur formulations must be strictly avoided to prevent chemical reactions that could lead to component failure.

Taboo 2: Do Not Use Toxic and Hazardous Cleaning Agents Containing Fluorine or Benzene

Cleaning agents containing fluorine or benzene not only pose health risks to operators and harm the environment, but may also react adversely with PCB materials or component packaging, causing irreversible material damage.

Correct Practice: Choose specialized electronic cleaning agents that are phosphorus-free, have low VOCs (Volatile Organic Compounds), and offer high insulation properties. Alternatively, adopt environmentally friendly solutions using deionized water mixed with isopropyl alcohol in appropriate proportions, ensuring compatibility between the cleaning agent and component materials.

II. Ultrasonic Parameter Setting Taboos: Power and Temperature Are Core Control Points
Taboo 3: Do Not Arbitrarily Increase Ultrasonic Power

Ultrasonic cleaning is a mainstream method for cleaning PCBs and precision components. However, excessively high power can have serious consequences. Overly strong cavitation effects can cause deformation of micro-component leads, cracking of packaging, and even solder joint detachment or rupture of ceramic capacitors. Industry recommendations suggest controlling ultrasonic power density at approximately 0.3 W/cm². For precision components such as BGAs (Ball Grid Arrays), a low-power mode is even more essential.

Taboo 4: Do Not Arbitrarily Increase Cleaning Temperature

Precision electronic components are extremely sensitive to temperature. Excessively high cleaning temperatures can cause deformation of plastic-encapsulated components, damage to internal circuits, and even lead to failure of electrolytic capacitors. It is recommended to precisely control the cleaning temperature between 30°C and 45°C, with a closed-loop temperature control system for real-time monitoring.

Taboo 5: Do Not Exceed Recommended Cleaning Time per Batch

Total cleaning time should be kept within a reasonable range. Generally, it is advised that cumulative daily cleaning time does not exceed 15 minutes. Prolonged exposure to the ultrasonic environment may induce metal migration phenomena, affecting the electrical performance of the circuitry.

III. Electrostatic Protection Taboos: Electrostatic Discharge Is an Invisible Killer
Taboo 6: Do Not Operate Equipment Without Proper Grounding

Chips, sensors, and other components on PCB boards are highly sensitive to static electricity. Electrostatic voltages exceeding 100V can cause breakdown damage. Industrial cleaning equipment must be equipped with a reliable electrostatic grounding device, ensuring the equipment's grounding resistance is less than 4Ω.

Taboo 7: Do Not Allow Operators to Work Without Anti-Static Equipment

Operators must wear anti-static wrist straps and anti-static gloves before handling workpieces. Static electricity from the human body is a common cause of damage to precision components; even a slight oversight can cause irreversible harm.

IV. Sensitive Component Taboos: Some PCBs Are Naturally "Water-Sensitive"
Taboo 8: Do Not Clean PCBA Containing Specific Sensitive Components

The following types of PCB boards or components should avoid ultrasonic cleaning or require special protective measures:

V. Operational Procedure Taboos: Details Determine Success or Failure
Taboo 9: Do Not Open the Cleaning Chamber or Protective Door While the Equipment Is Operating

Opening the cleaning chamber during operation can cause cleaning agent splashing, posing safety hazards. It may also introduce dust contamination to the workpieces and interfere with inspection accuracy.

Taboo 10: Do Not Send Workpieces with Residual Moisture Directly to Inspection or Drying Areas

Residual moisture can affect the image quality of visual inspection and may also lead to component short circuits. After cleaning, PCBs should be placed in an oven at 40°C to 50°C for 20 to 30 minutes, or processed using a centrifugal dryer (approximately 1200 rpm) for dehydration, ensuring complete drying before proceeding to the next stage.

Taboo 11: Do Not Operate Equipment with Known Faults or Arbitrarily Modify Parameters

If equipment abnormalities are detected, operations should be halted immediately for maintenance. Operating with known faults is strictly prohibited. Arbitrarily modifying critical parameters such as inspection settings or cleaning time may result in inadequate cleaning or component damage, affecting product quality.

Taboo 12: Do Not Proceed with Batch Cleaning Without Performing Compatibility Testing

Before batch cleaning of new board types or new component models, compatibility testing must be conducted to verify the effects of the cleaning process on component materials, solder joint reliability, and electrical performance. Mass production cleaning should only proceed after confirming no anomalies.

Conclusion
With the solicitation of comments for the mandatory national standard "General Safety Requirements for Industrial Washing Machinery" in 2025 and the updated implementation of safety specifications for high-pressure water jet cleaning operations, safety requirements in the precision industrial cleaning field are becoming increasingly stringent. For the cleaning of PCB boards and precision components, every standardized operation is a guarantee of product quality. By remembering the taboos outlined above, selecting appropriate equipment, employing scientific parameters, and following standardized procedures, we can ensure "zero damage" to precision components during the cleaning process, safeguarding the long-term reliability of electronic products.