Cleanroom Consumables: LPC Testing for Cleanliness

Posted on by

In industries requiring extremely high cleanliness such as precision manufacturing, medical consumables, and semiconductors, the presence of tiny particles can directly impact product performance and reliability. Liquid Particle Counting (LPC) testing is an efficient cleanliness evaluation method that quantifies particle shedding from tested materials’ surfaces, providing crucial data for product quality control.

1. Core Purpose of LPC Testing

The primary goal of LPC testing is to assess the number of particles released from tested materials such as cleanroom wipes, swabs, and other cleaning tools during use. Particles entering production environments or contacting sensitive products (e.g., chips, medical devices) may cause contamination, short circuits, or failures. LPC testing precisely quantifies particle release levels, enabling selection of materials that meet cleanliness standards and reduce contamination risks.

2. Testing Method and Procedure

  • Sample Preparation:
    Samples must be kept sealed to avoid environmental particle contamination. Textile samples (wipes) require neat-cut edges to ensure consistent testing areas; swabs should remain in intact packaging to maintain sample integrity.

  • Soaking and Use Simulation:
    Samples are fully immersed in ultrapure water and mechanically stirred to simulate real usage scenarios such as wiping or agitation. This promotes thorough detachment and dispersion of particles from the material surface into the water.

  • Particle Counting and Analysis:
    A high-precision liquid particle counter quantifies particles in the water across various size ranges. Results are expressed as particle density per unit area (counts/cm² or counts/m² for textiles) or total particle count per individual swab (counts/tip).

  • Testing Efficiency:
    Each sample test takes approximately 40 minutes, supporting rapid batch testing and enabling real-time quality monitoring during production.

3. Technical Points and Standardization

  • Sample Size:
    Textile wipes require 3 independent samples; swabs require 60 individual tips to ensure data representativeness.

  • Environmental Control:
    Testing is performed entirely within cleanrooms or laminar flow hoods to avoid external particle interference.

  • Particle Size Range:
    Particles sized 0.5 μm to 25 μm are typically counted, with focus on those most impactful to downstream products.

4. Application Fields

  • Electronics and Semiconductor Industry:
    Monitors particle release from cleanroom wipes and swabs used in wafer processing to prevent microscopic dust contamination impacting chip yields.

  • Medical Consumables:
    Evaluates cleanliness of surgical swabs and medical dressings to avoid particle contamination entering the body or pharmaceuticals.

  • Precision Instrument Manufacturing:
    Verifies suitability of cleaning tools such as optical lens wipes, ensuring particulate-free assembly environments.

5. Value of LPC Testing

  • Risk Prediction:
    Identifies high particle-releasing materials in advance, preventing batch quality issues caused by contamination.

  • Process Optimization:
    Guides suppliers to improve material washing, cutting, and packaging processes to reduce particle adherence.

  • Compliance Assurance:
    Ensures adherence to international cleanliness standards such as ISO 14644 and GMP.

Special Note:
Some cleanroom wipe manufacturers lack in-house testing capabilities; purchasers are advised to choose suppliers like USTER, which have professional testing laboratories and perform rigorous pre-shipment inspections.

6. Conclusion

As industrial cleanliness standards continue to rise, LPC testing has become an essential step in material selection and process control for cleanroom consumables. USTER, as a professional manufacturer with advanced testing equipment and scientific protocols, provides a reliable quality safeguard for highly sensitive industries, supporting a leap from “clean” to “ultra-clean” standards.

Cleanroom Wipes: APC Testing & Particle Control

Posted on by

In industries with extremely high cleanliness requirements such as semiconductor manufacturing, precision electronics, and medical equipment, the Air Particle Count (APC) of cleanroom wipes is a key indicator to evaluate their cleanliness and suitability. Even microscopic particles at very low concentrations can cause circuit shorts, device failures, or contamination of medical instruments, affecting product yield and safety. This article provides a detailed overview of the purpose, principles, procedures, and quality control aspects of APC testing for cleanroom wipes, helping enterprises scientifically select high-quality wipes.

1. Purpose and Significance of APC Testing

APC testing aims to simulate particle release during the dry, dynamic use of cleanroom wipes and quantitatively assess their potential contamination risk to the cleanroom environment. In ultra-clean processes like semiconductor wafer fabrication, particle presence can directly cause manufacturing defects. APC testing helps screen low-particle-release wipes to ensure they meet strict cleanroom requirements.

2. Principles and Key Parameters of APC Testing

  1. Testing Principle
    APC testing is based on light scattering technology. Particles suspended in air scatter a laser beam; the intensity of scattered light correlates with particle size and number. Particle counters capture the scattered signals, enabling precise counting of particles in the 0.3–2.0 μm size range, focusing especially on critical particles ≥0.5 μm.

  2. Key Parameters

  • Testing Equipment: Helmke Drum simulates real wiping action by rotating at 10 rpm, generating mechanical friction similar to actual use.

  • Units: Results are reported as counts/ft³/min/pc (particles per cubic foot per minute per piece) or counts/m² (particles per square meter), indicating particle release intensity per unit area or per wipe piece.

  • Sample Requirements: Five sealed samples with neat-cut edges to avoid fiber shedding from edges that might interfere with results.

3. Standardized Testing Procedure

  1. Sample Preparation

  • Samples are unpacked in an ISO Class 5 or better clean environment to avoid external contamination.

  • Cleanroom tweezers are used to fix wipes flat onto the Helmke Drum’s inner wall, avoiding folds or pressure.

  1. Equipment Operation

  • The drum rotates steadily at 10 rpm, simulating wiping-induced mechanical stress.

  • The air sampling tube is positioned 5 ± 2 cm from the drum’s edge, connected via flexible conductive tubing to the particle counter, sampling at 28.3 L/min.

  1. Data Collection

  • The particle counter measures particle counts mainly ≥0.5 μm over about 40 minutes per sample, recording the dynamic release curve and calculating average particle release.

4. Quality Control and Considerations

  1. Environmental Control

  • Laboratory conditions are maintained at 20–25°C, 40–60% humidity, and ISO Class 5 cleanliness.

  • The same operator performs all tests to minimize human error.

  1. Equipment Calibration

  • Regular calibration of particle counter sensitivity and Helmke Drum speed is mandatory.

  • Blank control tests (empty drum runs) are conducted to exclude background particle interference.

  1. Sample Uniformity

  • Wipes from different batches and edge finishing methods (laser cutting, ultrasonic sealing) are tested separately since edge quality directly impacts fiber shedding.

5. Application Scenarios and Standards Reference

  • Semiconductor Manufacturing: Compliance with Class 1 cleanroom standards (≤10 particles ≥0.1 μm per cubic meter) to prevent manufacturing defects.

  • Medical Sterile Packaging: Minimizing microparticle contamination to ensure surgical instrument and pharmaceutical safety.

  • Optical Device Cleaning: Avoiding scratches or fogging on lenses and sensors caused by particulate matter.

Relevant Standards:

  • SJ/T 11480-2014: Specifies instrument parameters and operational procedures for APC testing.

  • ASTM E1560: Relates non-volatile residue (NVR) analysis to particle release characteristics.

6. Conclusion

APC testing of cleanroom wipes scientifically simulates actual usage environments to quantify particle release risk, providing essential guidance for selecting materials suitable for high-cleanliness industries. As cleanroom technologies advance, future APC testing will integrate micro/nano particle characterization and AI data analytics to drive upgrades in wipe performance standards.

Cleanroom Consumables: IC/EI Testing & Clean Defense

Posted on by

In modern precision manufacturing, semiconductor processing, and healthcare industries, cleanroom consumables play a critical role in cleaning procedures. The ionic cleanliness of these materials directly impacts product quality and safety. Ion Chromatography (IC) and Extractable/Leachable Ions (EI) testing technologies serve as essential tools to characterize ionic contamination in cleanroom consumables and safeguard clean environments. This article provides a systematic overview of IC and EI testing systems based on ion chromatography, explaining their principles, workflows, industry applications, and technological innovations, helping industries enhance quality control.

1. Testing Principles and Technical Framework

The detection system follows a three-step procedure: extraction, separation, and quantification. Samples are immersed in ultrapure water (18.2 MΩ·cm) at 37°C to simulate actual usage conditions, allowing electrolytes in material surfaces and pores to dissolve fully. The ion chromatograph features dual systems: a cation system with carboxylic acid stationary phase and suppressed conductivity detection, and an anion system using a high-capacity hydroxide-selective column to separate 13 target ions precisely. Coupling with mass spectrometry (IC-MS) achieves ppt-level detection limits, significantly enhancing trace contaminant identification.

2. Standardized Testing Procedure

  • Sample Preparation:

    • For cleanroom wipes: weigh 60–70 g for cleanroom fabric or 30–35 g for nonwoven fabric to ensure representativeness.

    • For swabs: select 50 intact swabs, using specialized holders to submerge swab tips completely in solvent.

  • Extraction Process:

    • In a Class 100 clean bench, samples are placed in PTFE containers with 50 mL ultrapure water, agitated at 37°C for 2 hours.

  • Pre-Treatment:

    • Filter through triple 0.22 μm nylon membranes to remove particulates, ensuring purity of the test solution.

  • Chromatographic Analysis:

    • Gradient elution is applied with 20 mM methane sulfonic acid as the mobile phase for cations and KOH gradient elution for anions, achieving precise quantification.

3. Multi-Dimensional Quality Evaluation

The system detects six cations (including lithium Li⁺, sodium Na⁺) and seven anions (such as fluoride F⁻, chloride Cl⁻), with three evaluation metrics:

  • Residue per unit mass (μg/g): for fabric-based consumables.

  • Load per single item (μg/tip): for discrete products like swabs.

  • Release per unit area (μg/cm²): to standardize evaluation for materials with special morphologies.

4. Industry Applications

  • Semiconductor Manufacturing: Controls sodium ion contamination in photoresist coating steps to prevent wafer defects.

  • Biopharmaceuticals: Monitors endotoxin and ionic risks in cleanroom wipes to ensure sterile production environments.

  • Display Panel Manufacturing: Mitigates calcium and magnesium ion-induced film crystallization during wiping, improving product quality.

5. Technological Innovations

  • Online Dilution Technology: Enables detection across a wide concentration range from 0.1 to 1000 ppm in a single injection, catering to diverse testing needs.

  • Cation Compensation Algorithm: Effectively eliminates interference from ammonium ions (NH₄⁺) co-eluting with sodium ions, enhancing analytical accuracy.

  • Material-Solution Partition Coefficient Model: Maps laboratory test data to real-world conditions accurately, increasing practical relevance.

6. Quality Control Development Trends

With the implementation of the new ISO 14644-9:2022 cleanroom standards, IC/EI detection technology is evolving towards:

  • Intelligent Analysis: AI-assisted chromatogram interpretation systems to automatically identify unknown peaks.

  • Micro-scale Extraction: Development of micro-extraction devices reducing sample consumption to one-fifth of current standards.

  • Real-Time Monitoring: Portable ion chromatography instruments for rapid on-site screening and quality control.

Conclusion

IC and EI testing technologies for cleanroom consumables act as a “microscope” to detect ionic contamination in materials, forming a critical defense line in manufacturing quality control. As nanotechnology manufacturing and precision medicine advance, these technologies will continuously innovate, driving upgrades in ultra-clean materials and processes, and providing robust technical support to industries.

Wipes/Swabs: NVR Testing Explained

Posted on by

Non-Volatile Residue (NVR) is a critical indicator for assessing surface cleanliness of materials in industrial production, directly affecting product reliability in electronics, pharmaceuticals, and precision manufacturing. This article focuses on wipers and swabs, establishing a high-sensitivity NVR testing method based on solvent extraction and gravimetric analysis. By standardizing the process, the method enables quantitative analysis of residues on textiles and swabs, providing scientific support for quality control in cleaning processes.

2. Introduction

NVR refers to non-volatile substances remaining on material surfaces after solvent extraction. Its content directly impacts product performance in fields such as semiconductor manufacturing, where wafer surface NVR can cause circuit shorts or device failures. This paper develops a quantifiable NVR detection system for wipers and swabs by optimizing solvent selection, extraction procedures, and data calculation models.

3. Materials and Methods

1. Experimental Materials

  • Samples: Wipers (6 pieces), Swabs (120 swab tips)

  • Solvents: Isopropanol (IPA, ≥99.7%), Ultrapure Water (DIW, 18.2 MΩ·cm), Anhydrous Ethanol (≥99.8%), Petroleum Ether (boiling range 60–90°C)

  • Equipment: Temperature-controlled evaporation apparatus (±0.1°C), electronic balance (accuracy 0.1 mg), vacuum filtration unit (0.45 μm pore size)

2. Testing Procedure

  • Solvent Soaking:

    • Wipers: Cut to a standard size (e.g., 10×10 cm²) and soaked in 200 mL of selected solvent with ultrasonic agitation for 30 minutes.

    • Swabs: 120 swab tips soaked in 500 mL solvent with mechanical shaking for 1 hour.

  • Solution Processing: Filter to remove particles (>0.45 μm), collect filtrate.

  • Evaporation to Constant Weight: Transfer filtrate to pre-weighed evaporation dishes; evaporate in 80°C water bath until constant weight (mass difference ≤0.2 mg between two weighings).

3. Residue Calculation Formulas

  • Wipers NVR (mg/cm²) = (Residue mass in mg) / (Wiper area in cm²)

  • Swabs NVR (mg/tip) = (Residue mass in mg) / (Number of swab tips)

4. Key Parameters

  • Total test duration: Approximately 9 hours (including 6–7 hours evaporation)

  • Temperature control during evaporation: 80±2°C to avoid residue decomposition and measurement bias

4. Results and Discussion

1. Effect of Solvent Choice on Extraction Efficiency

  • Isopropanol (IPA) achieves extraction efficiency up to 92% for oil-based residues, suitable for electronics industry wiper testing.

  • Ultrapure water is more sensitive to water-soluble ionic residues such as Na⁺ and Cl⁻, making it ideal for pharmaceutical-grade swab testing.

2. Method Validation

  • Wipers spiked with silicone oil (1.0 mg/g) showed recovery rate of 98.5% with relative standard deviation (RSD) of 2.1%.

  • Swabs spiked with polyethylene glycol (0.05 mg/tip) showed recovery rate of 95.3%, RSD 3.8%, confirming accuracy and repeatability.

3. Comparison with Industry Standards
The method’s results for textile NVR closely match ISO 9022-12:2015 optical component cleanliness tests, with deviations less than 5%. Increased swab sample size (120 tips) improved statistical significance (p<0.01).

4. Application Cases

  • A semiconductor company applying this method found that reducing wiper NVR from 0.8 mg/g to 0.2 mg/g increased wafer yield by 12%.

  • In a medical device production line, NVR testing traced a microbial contamination incident to swab residue exceeding limits (0.15 mg/tip, 50% over limit).

5. Conclusion

The presented NVR testing method, combining multi-solvent extraction and high-precision gravimetric analysis, enables accurate quantification of residues on wipers and swabs. Coupled with standardized procedures, it provides robust technical support for quality control in cleaning consumables, especially for industries demanding high cleanliness.

Cleanroom Swab Mfrs: Selection Guide from Certs to Service

Posted on by

Cleanroom swabs are essential cleaning tools in industries such as precision manufacturing, biotechnology, microelectronics, and optical instrumentation. Their quality directly impacts contamination control, product yield, and production efficiency. Choosing a reliable cleanroom swab manufacturer is critical for procurement professionals. This article provides a systematic selection guide based on five key dimensions: production qualifications, manufacturing capacity, testing capability, cost-performance ratio, and service support.

1. Production Environment and Raw Materials Are Fundamental

Cleanroom Grade Determines Product Purity

High-quality cleanroom swabs must be produced in ISO-certified Class 100 or higher cleanrooms (e.g., Class 10). For example, Shenzhen USTER Technology Co., Ltd. operates dedicated Class 10 and Class 100 cleanrooms. Manufacturers without such environments can only produce low-grade swabs, unsuitable for critical cleanroom applications.

Compliant Raw Materials Ensure Product Stability

Common materials include PP (polypropylene) handles combined with high-density polyurethane foam or cleanroom cloth tips. All raw materials must be certified to meet industry standards—free from harmful volatile compounds, ionic residues, halogens, or sulfur—to ensure safety in sensitive environments.

2. Manufacturing Scale Affects Delivery and Cost

Large-Scale Automated Production Ensures Supply Stability

Top-tier manufacturers typically operate over 10,000 square meters of cleanroom space with automated production lines, enabling mass production and cost control for large-volume orders.

Customization Capability Is Key for Specialized Applications

For sectors like HDD, optics, or SMT, non-standard designs such as dual-head swabs, shaped foam tips, or extended handles are often required. This demands not just manufacturing capacity but also R&D capabilities. Manufacturers like USTER have dedicated R&D teams for such flexible production.

3. In-House and Third-Party Testing Ensures Reliability

Key Performance Indicators:

  • LPC (Liquid Particle Count): Measures particle shedding in liquid environments.

  • APC (Airborne Particle Count): Indicates particle release in air.

  • IC (Ion Chromatography): Evaluates ionic content critical for microelectronics.

  • Absorbency & Residue Tests: Determine cleaning effectiveness and residue-free performance.

Third-Party Certification Builds Trust

Reliable manufacturers submit products for third-party lab certification (e.g., SGS, ROHS, REACH), enhancing customer confidence and proving product consistency.

4. Cost-Performance Balance: Not Always About the Price

International Brands: Texwipe and Berkshire

  • Advantages: Renowned quality and stability; widely used in semiconductor and medical industries.

  • Disadvantages: Expensive and long lead times; best for premium projects.

  • Ideal for: High-budget, ultra-clean applications requiring top-tier standards.

Recommended Domestic Brand: USTER

  • Advantages: Offers high-end quality at a more competitive price; many resellers and OEM partners choose USTER as a preferred supplier.

  • Market Reputation: Frequently recommended for large-scale or cost-sensitive projects without compromising on quality.

5. Service and Support Define Long-Term Value

Technical Support and Fast Response Are Crucial

Leading manufacturers offer technical consulting and product selection advice. For example, USTER has a dedicated technical support team ready to assist clients with samples, data, and custom solutions.

Logistics and After-Sales

Domestic manufacturers typically have quicker logistics. USTER partners with reliable carriers like KY Express and Deppon, ensuring fast, safe delivery with anti-static, moisture-proof packaging.

6. Final Recommendations

Client Type Recommended Brands Procurement Strategy
Overseas High-End Texwipe, Berkshire Plan ahead, prioritize performance, high budgets
Domestic Users USTER, Other Top Chinese Focus on price-performance and logistics
Distributors/Agents Partner with USTER, etc. Competitive pricing, fast restocking, brand value

Conclusion:

Though cleanroom swabs are small, they play a crucial role in contamination-sensitive environments. Choosing a supplier goes far beyond price—it’s about technical capability, testing accuracy, and responsive service. By trial sampling and small-batch testing, clients can better validate product performance before establishing long-term partnerships.

Multi-Purpose Wipes: Benefits & Applications

Posted on by

In industrial manufacturing, precision processing, and routine maintenance, the selection of cleaning tools directly impacts operational efficiency and cost control. Multi-purpose wipes, as an innovative cleaning material, have become a preferred solution across industries thanks to their unique material composition and functional benefits. This article provides an in-depth analysis of their core advantages and application scenarios to help users understand their value.

I. Five Core Advantages of Multi-Purpose Wipes

1. Superior Cleaning Power & Material Stability
Made from polypropylene (PP) and wood pulp composite fibers, multi-purpose wipes feature a three-dimensional structure that provides excellent water and oil absorption. This structure enables the removal of contaminants like lubricants, coolants, and metal debris from surfaces. The fibers can also reach into gaps and crevices, delivering a “one-wipe-clean” effect and reducing repetitive cleaning.

2. Durability Combined with Cost-Efficiency
Compared to traditional cotton rags or paper towels, multi-purpose wipes offer over 50% higher tear resistance and tensile strength, even when wet. Their reusability and washability reduce consumption and save 30%–50% in long-term cleaning costs.

3. Lint-Free and Environmentally Safe
With electrostatic surface treatment, these wipes release virtually no lint, avoiding blockages or contamination in precision instruments. They are also certified lead-free and fluorescent agent-free, making them suitable for use in food processing, healthcare, and other safety-critical environments.

4. Flexible Adaptation to Different Scenarios
Available in various weights from 55g to 110g:

  • Lighter wipes are soft and suitable for cleaning precision electronics.

  • Heavier wipes are more durable and can handle heavy-duty cleaning, such as removing grease and metal shavings.

5. Easy Handling Improves Efficiency
Usable for both dry and wet wiping, the wipes retain strength and flexibility, easily wrapping around tools or reaching into complex structures. This improves cleaning efficiency by more than 20%.

II. Typical Application Scenarios

1. Industrial Manufacturing & Maintenance

  • Machining (CNC, bearings, gears): Removes cutting fluids and metal dust without fiber shedding.

  • Automotive & Rail Maintenance: Absorbs engine oil, brake dust, and grease efficiently.

  • Aerospace Components: Ideal for electronics and avionics with strict cleanliness requirements.

2. Printing & Surface Treatment

  • Screen Printing Equipment: No lint during ink removal; ensures no clogging.

  • Pre-Treatment for Plating or Spraying: Removes degreasing agents and polishing compounds, enhancing coating adhesion.

3. Emergency & Special Environments

  • Oil Spill Response: Absorbs up to 10x its own weight in oil; flame-retardant versions available.

  • Laboratory Cleaning: Corrosion-resistant materials are safe for use with acids and alkalis.

III. Industry Comparison: Multi-Purpose Wipes vs. Traditional Materials

Metric Multi-Purpose Wipes Cotton Rags Regular Nonwoven Cloth
Cleaning Cost per Use Low (reusable) Medium High (disposable)
Lint Residue Minimal High Low
Oil Absorption (g/m²) 80–120 30–50 50–70
Solvent Resistance Excellent Poor Good

IV. Purchasing & Usage Recommendations

  • Choose by Scenario:

    • For light-duty use, select models like X5 or X6.

    • For heavy grease and oil, choose X7 or X8.

  • Cleaning Guidelines:
    Use neutral detergent with water temperatures below 60°C. Avoid prolonged sun exposure.

  • Eco-Friendly Disposal:
    Damaged wipes can be recycled as industrial filler materials, supporting circular economy practices.

V. Conclusion

Multi-purpose wipes provide an innovative solution that addresses common challenges in industrial cleaning—balancing efficiency, cost, and environmental impact. Their high absorbency, durability, and safety make them ideal for a wide range of industries. As a pioneer in this field, Uster continues to expand its product portfolio and deliver specialized cleaning solutions, helping enterprises improve cleaning standards while advancing sustainability and cost reduction goals.

Cleanroom Wipes/Swabs: Absorption Test Methods

Posted on by

1. Testing Principle and Importance

Cleanroom wipes and swabs are essential consumables in precision manufacturing industries. Their liquid absorption performance directly affects cleaning efficiency in sectors such as semiconductors, optical panels, and medical devices. This test quantifies liquid absorption per unit area or weight of material, providing critical data for material selection and process validation. The testing follows standards like IEST-RP-CC004.3, focusing on absorption characteristics of typical industrial solvents such as ultrapure water and isopropyl alcohol (IPA).

Lab technicians at Youstech are shown testing the water absorbency of cleanroom wipes.

2. Key Influencing Factors

2.1 Material Structural Properties

  • Fiber Type: Polyester/nylon blends absorb 15–20% more IPA than pure cotton materials.

  • Fabric Weight: 80g/m² wipes absorb 30–40% more liquid compared to 50g/m² fabric.

  • Weaving Technique: Knitted fabrics retain over 25% more liquid than plain-woven fabrics.

  • Surface Treatment: Hydrophilic treatments can increase ethanol absorption by 50–70%.

2.2 Unique Swab Structure

  • Winding Density: Tips with 8–10 wraps per millimeter retain 15% more liquid than loosely wrapped ones.

  • Rod Material: PP handles offer better ESD performance than wooden rods (surface resistance <10⁹Ω).

3. Standardized Testing Procedure

3.1 Sample Preparation

  • Wipes: Cut 5 specimens of 10×10 cm each (as per ASTM D5729).

  • Swabs: Select 5 swabs from the same batch with intact cotton tips.

  • Pre-treatment: Dry at 40°C for 2 hours, then equilibrate at 23±1°C and 50±5% RH for 24 hours.

3.2 Test Settings

  • Soaking Solutions: Ultrapure water (18.2 MΩ·cm) and ≥99.7% pure isopropyl alcohol.

  • Immersion Time: 60±5 seconds (based on SEMI E129 standard).

  • Drip-off Angle & Time: 45° hanging angle, 120 seconds drainage.

3.3 Precision Weighing Process

Using a 0.0001g accuracy balance:

  • Wipe Absorption (mL/m²) = (Wet weight − Dry weight) / (Solution density × Area)

  • Swab Absorption (μL/tip) = (Wet weight − Dry weight) × 1000 / Solution density

4. Key Quality Control Points

  • Environment: Class 100 cleanroom with temperature fluctuation ≤±0.5°C/h

  • Handling: Use ESD-safe tweezers to avoid contamination.

  • Data Validation: Conduct 3 parallel tests per sample; RSD ≤ 5%

  • Calibration: Perform 3-point weight calibration weekly (0.1g, 1g, 10g)

This testing system not only supports quality control of cleanroom consumables but also contributes valuable data for R&D of new materials. As 5G chip manufacturing pushes cleanliness standards toward the 0.1μm level, liquid absorption testing is evolving toward nanoscale observation and in-situ dynamic analysis, ushering cleanroom materials into a new era of precision diagnostics.

Cleanroom Wipes: Electrostatic Test Methods

Posted on by

In electrostatic-sensitive environments such as electronics manufacturing and precision instrument maintenance, cleanroom wiping consumables (e.g., cleanroom wipes, cleanroom paper, and swabs) must offer reliable electrostatic discharge (ESD) protection. Effective dissipation of static electricity is essential to prevent damage to sensitive components. This article systematically outlines the commonly used test methods for evaluating anti-static properties of these materials, based on industry standards and real-world requirements.

1. Surface Resistance Method – Basic Conductivity Assessment

Principle:
Surface resistance is the ratio of direct current voltage to current between two points on the surface of a material (unit: ohms, Ω). Lower resistance indicates better conductivity and stronger ESD dissipation capability.

Testing Procedure:

  • Sample Preparation: Select 5 samples and pre-condition them in a controlled environment (23±2°C, 50±5% RH) for at least 4 hours.

  • Measurement: Place the electrodes (or weighted probes) of the surface resistance tester on the sample, press the test button, and record the reading.

Evaluation Criteria:

  • Anti-static material: Resistance < 10¹¹ Ω

  • High-quality anti-static material: 10⁵ Ω – 10⁹ Ω (balanced ESD dissipation and insulation)

  • Insulating material: Resistance > 10¹² Ω (prone to static buildup)

Advantages:
Quick and simple; suitable for on-site screening in production environments.

2. Decay Time & Half-Life Method – Charge Dissipation Efficiency

Principle:
After charging the sample using a high-voltage source, its voltage decay to 50% of the initial level (half-life) or complete decay is measured using a non-contact electrostatic voltmeter. This evaluates how quickly the material dissipates static charges.

Testing Procedure:

  • Sample Preparation: Pre-treat 10 samples for at least 4 hours in a controlled environment.

  • Charge & Measure: Charge using corona discharge or friction method and monitor the decay curve of voltage over time.

Key Indicator:
Shorter decay time = better ESD performance. Semiconductor industries typically require decay time < 0.1 seconds.

Application:
Ideal for high-ESD-sensitive applications like chip fabrication.

3. Triboelectric Voltage Method – Real-World Friction Simulation

Principle:
The sample is rubbed against a standard fabric (e.g., nylon cloth) under a specified tension until it reaches electrostatic stability. The peak and average voltages generated simulate ESD risk from actual wiping motions.

Testing Procedure:

  • Equipment: A friction apparatus and electrostatic voltmeter compliant with GB/T 24249-2009 standard.

  • Sample Details: Pre-treat 10 samples for ≥4 hours; each test lasts 30 minutes.

Evaluation Criteria:

  • Grade 1 anti-static material: Friction voltage ≤ 200V

  • Grade 2 material: 200V–500V

Advantages:
Highly practical; mimics real-use conditions and supports cleanroom material classification.

4. Testing Conditions & Key Guidelines

  • Environmental Control: All tests must be conducted at 20–25°C and 40%–60% RH.

  • Pre-treatment Importance: Eliminates moisture-related influence on resistance values to ensure data reliability.

  • Sample Quantity: Surface resistance test requires 5 samples; other methods require 10 to account for material variability.

  • Data Recording: Must document max, min, and average values for comprehensive performance evaluation.

5. Conclusion & Selection Recommendations

Multiple tests are essential to comprehensively evaluate the anti-static performance of cleanroom wiping materials:

  • Surface Resistance Method assesses base-level conductivity.

  • Decay Time Method evaluates charge dissipation speed.

  • Triboelectric Method simulates practical static generation risks.

For real-world application, users should align with industry standards (e.g., GB/T 24249-2009) and operational scenarios (e.g., Class 100 cleanrooms, high-precision electronics assembly). It is recommended to select products with resistance between 10⁵–10⁹ Ω and triboelectric voltage ≤200V to ensure effective ESD control while maintaining operational efficiency.

Industrial Wipes: Solving Chemical Production Cleaning

Posted on by

In the daily chemical production industry, managing cleaning processes is critical for controlling costs and improving production efficiency. Many companies still rely on traditional white cotton cloths as their primary cleaning consumables. Although initially inexpensive, these cloths often suffer from unstable quality, poor cleaning efficiency, and high waste disposal costs, resulting in overall high operational expenses. This article presents a detailed case study of a well-known domestic daily chemical company to analyze how industrial wipes, through technological innovation and tailored application, can dramatically improve cleaning processes and significantly reduce costs.

  1. Five Major Pain Points of Traditional White Cotton Cloth
    Through an in-depth survey of the company’s washing and care workshop, five systemic issues were identified:

  • Storage management challenges: The bulky packaging of 20kg per bundle occupies over 63 cubic meters of warehouse space, complicating logistics and inventory control.

  • Significant quality fluctuations: Cotton content tests showed some batches as low as 32%-45%, leading to nearly 30% lower absorption efficiency.

  • Poor cleaning effectiveness: Equipment surfaces retained up to 17% residue, requiring multiple repeated wiping cycles, increasing labor and material consumption.

  • High waste disposal costs: Post-use weight increased by 35%, with annual waste disposal costs exceeding 180,000 RMB, creating environmental pressures.

  • Prominent hygiene and safety risks: Microbial over-limit rate reached 22%, raising the risk of cross-contamination, which affects product quality and worker health.

  1. Innovations and Customized Applications of Industrial Wipes
    In response to these challenges, Uster developed a tailored industrial wiping solution matching different cleaning scenarios in the workshop:

  • Heavy oil contamination areas use highly absorbent polypropylene (PP) wipes for quick removal of stubborn grease.

  • General cleaning scenarios employ multifunctional wipes that balance absorbency, stain removal, and durability.

  • Cleanrooms and laboratories utilize cleanroom-grade wipers such as lint-free paper and cleanroom wipes, ensuring minimal fiber shedding and particle contamination.
    After six months of practical application, production efficiency increased significantly, the cleaning environment improved, and overall cleaning costs dropped by more than 15% compared to traditional methods.

  1. Conclusion
    This case study illustrates that seemingly economical traditional white cotton cloths can ultimately increase enterprise operating costs due to multiple drawbacks. Facing increasingly strict production standards and environmental regulations, adopting professional industrial wipes and scientific cleaning management strategies is essential for reducing costs, ensuring product quality, and enhancing competitiveness. Enterprises are encouraged to explore new cleaning materials and technologies for sustainable production optimization.

Premium Cleanroom Wipes: Key Requirements Guide

Posted on by

In industries with extremely high cleanliness requirements such as electronics optics, semiconductor manufacturing, and biopharmaceuticals, cleanroom wipes are essential consumables that ensure process stability and product quality. A high-quality cleanroom wipe must not only have excellent cleaning efficiency but also meet strict physical, chemical, and biological standards. This article analyzes the seven core performance parameters that high-quality cleanroom wipes should satisfy, helping enterprises make precise selections to improve cleanroom process stability and product yield.

1. Strict Control of Particle Shedding
Particle shedding during use directly affects the cleanliness level.

  • Visible Particles: The wipe should not shed visible fibers or particles to avoid scratching or secondary contamination. High-density weaving and laser or ultrasonic sealing reduce fiber breakage risk.

  • Submicron Particles: The release of submicron particles must be measured by laser particle counters and comply with ISO 14644-1 standards. Using ultrafine fibers combined with multiple rounds of ultrapure water cleaning improves cleanliness.

2. Fiber Shedding Suppression
Fiber residue is a major concern affecting wiping effectiveness and equipment safety.

  • Use nonwoven fabrics or woven fabrics sealed by laser cutting or ultrasonic welding.

  • Comply with IEST-RP-CC004.3 fiber release testing to ensure particle emissions meet strict criteria.

3. Extremely Low Chemical Residue
High cleanliness applications are sensitive to chemical contamination and require strict control of ions and non-volatile residues (NVR).

  • Ion Contamination: Tested per IPC TM-650 2.3.28 to ensure no soluble ionic contamination.

  • Non-Volatile Residues: Use ultrapure water cleaning and solvent-free manufacturing to prevent organic or inorganic deposits that may corrode equipment or affect chemical reactions.

4. Biological Load Control
Especially in pharmaceutical and biological labs, wipes must meet sterile or low microbial load standards.

  • Sterilization treatments reduce microbial counts.

  • Packaging with double clean bags or vacuum sealing prevents contamination during transport and storage.

5. Anti-Static Performance
Electrostatic discharge (ESD) can damage sensitive electronic components; high-quality wipes need stable anti-static properties.

  • Surface resistivity should range between 10⁵ to 10⁹ ohms, complying with ANSI/ESD S20.20 standards.

  • Permanent anti-static additives such as carbon fibers or conductive threads are preferred over temporary coatings.

6. Clean Packaging and Traceability

  • Class 100 wipes must be packaged in Class 100 cleanrooms to avoid external contamination.

  • Provide detailed batch test reports including particle counts, ion content, and microbial data, meeting ISO 9001 quality management requirements.

Summary
High-quality cleanroom wipes are vital guardians of precision manufacturing and R&D, with performance spanning material selection, manufacturing processes, stringent testing, and clean packaging. When selecting wipes, users should consider specific application requirements, reference industry standards, and verify through third-party testing to ensure optimal particle shedding, chemical contamination, biological safety, electrostatic control, and traceability. Only wipes that balance these multidimensional performance factors can truly act as the “invisible protectors” of clean environments, helping enterprises continuously enhance product quality and process stability.