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Oil Absorbent Papers: Selection Guide for Spills

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Industrial oil absorbent papers are essential cleaning consumables widely used in manufacturing and maintenance. They mainly fall into three categories based on material and performance: heavy-duty oil absorbent wipes, cleanroom-compatible oil absorbent wipes, and oil absorbent pads. Different application scenarios demand different types of oil absorbents. Choosing the right product not only improves cleaning efficiency but also reduces costs and contamination risks. Here’s a detailed guide on selecting industrial oil absorbent papers for various scenarios.

1. Wiping Oil from Mechanical Equipment

Oil stains on machinery are typically small amounts caused by routine production leakage. For such cases, heavy-duty oil absorbent wipes are recommended.

  • Product Features:
    Made from advanced MELTBLOWN polypropylene material, these wipes offer exceptional oil absorption, capable of absorbing several times their own weight.

  • Packaging:
    Available in folded sheets or roll formats. Rolls have a perforated design for easy tear-off of single sheets, often paired with a dedicated dispenser for convenience.

  • Typical Industries:
    Widely used in metal processing, energy, power generation, and machinery manufacturing for routine oil stain cleaning.

2. Wiping Oil in Cleanroom Environments

Cleanrooms require extremely low particulate levels, so oil wiping must meet strict low-dust and high-absorption standards. Thus, cleanroom-compatible oil absorbent wipes are necessary.

  • Advantages:
    Low particle shedding meets cleanroom standards, preventing secondary contamination, while maintaining strong oil absorption.

  • Applications:
    Ideal for semiconductor, electronics manufacturing, pharmaceutical cleanrooms, and other high-purity environments.

3. Emergency Response for Oil Spills

In cases of large oil spills, standard oil absorbent wipes are insufficient. Heavy-duty oil absorbent pads are recommended.

  • Shapes and Uses:
    Available in sheets, rolls, and pillow shapes to suit different needs. For example, roll pads can be used to surround and contain spills, effectively preventing spread; sheets are suitable for large-scale absorption such as offshore oil spill cleanup.

  • Material and Performance:
    Made of superfine polypropylene fibers, these pads absorb up to ten times their own weight in oil. They absorb oil but repel water, making them perfect for cleaning oil spills on water surfaces.

Summary:

Choosing the right industrial oil absorbent paper depends on the specific application and type of oil contamination. Heavy-duty oil absorbent wipes suit routine mechanical equipment cleaning, cleanroom oil wiping requires low-lint oil absorbent wipes, and large oil spill emergencies demand heavy-duty absorbent pads. Proper selection ensures a cleaner production environment, enhances oil spill management efficiency, and supports safer, environmentally friendly operations.

Industrial Wipes: Types & Selection Guide

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Industrial wipes are essential cleaning consumables widely used in manufacturing, equipment maintenance, and precision processing. Based on material and performance differences, industrial wipes can be categorized into three main types: Wood pulp + polyester composite, Wood pulp + polypropylene (PP) composite, and 100% polypropylene (PP). This article provides an in-depth analysis of the characteristics, core advantages, and typical applications of each type to help users make informed selections.

1. Classification Analysis: Material and Performance Comparison

  • Wood Pulp + Polyester Composite Wipes

    • Representative Products: Cleanroom wipes, multi-purpose wipes, SMT stencil wipes

    • Material Features: Wood pulp offers excellent liquid absorption, while polyester (PET) enhances abrasion resistance and tear strength.

    • Core Advantages: Suitable for both wet and dry use with low linting, ideal for environments with high cleanliness requirements, and leaves no fiber or particle residues after wiping.

  • Wood Pulp + Polypropylene (PP) Composite Wipes

    • Representative Products: Multi-purpose wipes

    • Material Features: Wood pulp improves water absorption; PP fibers provide softness, chemical resistance, and oil absorption.

    • Core Advantages: Economical and functional, reusable after washing, suitable for routine cleaning of oils and water stains, and gentle on surfaces.

  • 100% Polypropylene (PP) Wipes

    • Representative Products: Heavy-duty oil-absorbing wipes

    • Material Features: Made entirely of PP fibers through special processing, hydrophobic and oleophilic, capable of absorbing several times their own weight in oil.

    • Core Advantages: Designed specifically for oily contaminants, acid and alkali resistant, suitable for heavy oil pollution environments.

2. Typical Application Scenarios

  • Precision Electronics Manufacturing

    • Suitable Types: Wood pulp + polyester composite wipes (e.g., SMT stencil wipes, cleanroom wipes)

    • Applications: Cleaning solder paste residues from SMT stencil holes, wiping PCBs and other precision components to prevent static and particulate contamination, reducing equipment clogging risk.

  • Machining and Automotive Maintenance

    • Suitable Types: 100% PP heavy-duty oil wipes

    • Applications: Cleaning cutting fluids and lubricants from machine tools, absorbing oil leaks and hydraulic fluids in automotive repair, improving operational safety and efficiency.

  • Food and Pharmaceutical Industry

    • Suitable Types: Wood pulp + PP multi-purpose wipes

    • Applications: Cleaning equipment surfaces and water spills on production lines, used with food-grade disinfectants to meet hygiene standards.

  • Laboratories and Cleanrooms

    • Suitable Types: Wood pulp + polyester cleanroom wipes

    • Applications: Wiping laboratory instruments and cleanroom surfaces, used with solvents like alcohol or acetone to prevent cross-contamination.

3. Selection Recommendations

  • By contaminant type:

    • Oil-based contaminants → 100% PP oil-absorbing wipes

    • Water-based or mixed contaminants → Wood pulp composite wipes

  • By environmental cleanliness requirements:

    • Higher cleanliness → Cleanroom wipes or SMT-specific wipes

    • Regular workshops → Multi-purpose wipes

  • By cost control:

    • High-frequency use → Economical wood pulp + PP wipes, reusable

    • High-value scenarios → Wood pulp + polyester wipes with low lint and dust

4. Summary

Selecting the right industrial wipe can effectively improve cleaning efficiency and reduce maintenance costs. Wood pulp + polyester wipes excel in high-cleanliness applications, wood pulp + PP wipes offer cost-effective versatility, and 100% PP wipes specialize in oily contaminant cleanup. Enterprises should combine their industry characteristics, contaminant nature, and budget to scientifically select wipes and maximize their value.

Auto Glass Wipes: Selection & Use Guide

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In automotive paint shops, cleaning glass residue is a crucial step to ensure the vehicle surface is smooth and free of particulate contamination. Choosing professional residue-removal mesh wipes and mastering proper usage techniques can not only improve cleaning efficiency but also reduce operational costs. This guide provides detailed selection criteria and standardized operating procedures.

1. Selection Guide for Residue-Removal Mesh Wipes

Material Requirements:

  • Polyester + Viscose Composite:

    • Polyester offers high strength and abrasion resistance, suitable for repeated wiping without fiber shedding.

    • Viscose fibers enhance adhesion to residue, enabling thorough removal and minimizing secondary residue.

  • Environmental Safety:

    • Select materials with non-irritating chemical coatings that meet industrial safety standards, avoiding contamination of the workshop environment.

Mesh Design:

  • Unique Mesh Structure:

    • Mesh density should be uniform to trap residue particles while preventing fiber debris.

    • Surface micro-texture increases friction and improves residue removal efficiency.

  • Anti-Static Treatment:

    • Some premium products include anti-static properties to reduce dust attraction and lower particulate contamination risk.

Functionality Verification:

  • Residue Absorption Test:

    • Samples should be tested before purchase to confirm no glue marks or scratches remain on glass after wiping.

  • Durability:

    • After repeated folding, the wipe should maintain structural integrity without tearing or fiber loosening.

Specifications and Cost:

  • Size Adaptation:

    • Choose dimensions (e.g., 30cm×60cm) appropriate for glass area to avoid waste.

  • Cost Performance:

    • Prefer wipes that support multiple folds to maximize cleaning area per piece.

Brand and Certification:

  • Choose large industrial wipe manufacturers for product consistency and reliability, such as Shenzhen Youste Technology Co., Ltd., known for high quality and cost-effectiveness.

  • Reference collaboration with leading automotive manufacturers as proof of credibility.

2. Standard Operating Procedures for Residue-Removal Mesh Wipes

Operation Steps:

  • Pre-treatment:

    • Wear dust-proof gloves to avoid transferring hand oils to glass.

    • Unfold wipe and inspect for foreign matter.

  • Initial Wiping:

    • Wipe in a single direction across the glass surface at a uniform speed to leverage mesh structure for residue capture, avoiding back-and-forth friction that causes scratches.

  • Reuse by Folding:

    • After using one side, fold along the center line with the clean side facing out, and continue wiping.

    • Repeat folding multiple times until all clean surfaces are used.

  • Residue Disposal:

    • After wiping, fold used sides inward to prevent residue spreading.

    • Dispose of wipes in designated waste bins for centralized treatment.

Precautions:

  • Replacement Frequency:

    • Recommend replacing wipe after cleaning 1–2 glass panels to prevent residue buildup affecting effectiveness.

  • Prohibited Actions:

    • Avoid pressing hard to prevent residue penetrating deep into fibers.

  • Storage Requirements:

    • Store in a dry, dust-free environment to avoid moisture or oil contamination.

Safety and Efficiency Optimization:

  • Train operators regularly on correct usage and folding techniques to minimize waste.

  • Use low-volatile cleaners (e.g., neutral glue removers) to enhance removal of stubborn residues.

3. Why Choose Professional Residue-Removal Mesh Wipes?

  • Reduced Contamination Risk:

    • Mesh structure traps particulates, reducing dust pollution and meeting cleanliness standards of paint shops.

  • Cost Savings:

    • Multiple folds extend usage area, reducing the quantity of wipes needed compared to regular nonwoven fabrics.

  • Efficiency Improvement:

    • High absorption and durability shorten cleaning time, supporting high-speed assembly lines.

4. Conclusion

Proper selection and use of residue-removal mesh wipes are essential for ensuring glass surface quality and controlling costs in automotive manufacturing. Enterprises should evaluate materials, functions, and operating procedures comprehensively to choose efficient cleaning solutions tailored to their production needs.

PCB Cleanroom Wipes: Selection & Use Guide

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In the precision-demanding fields of PCB manufacturing and electronics, the choice of cleanroom wipes directly influences product quality and production environment cleanliness. This guide provides an in-depth overview of how to select and properly use cleanroom wipes specifically for PCB circuit board cleaning, covering material selection, edge finishing, size, cleanliness level, and practical usage tips.

1. Cleanroom Wipe Selection Guide

Material Selection:

  • Polyester Fiber: Most standard cleanroom wipes use 100% polyester double-knit fabric. This material offers a soft surface with low fiber shedding due to friction, suitable for general PCB cleaning tasks.

  • Ultrafine Fiber: Made from 80% polyester and 20% nylon blend, ultrafine wipes provide superior liquid absorption and are ideal for precision cleaning tasks such as chips and microprocessors, effectively removing fine particles.

Edge Finishing:

  • Laser Edge Sealing: Uses high-temperature fusion to melt fibers, reducing lint generation. Edges are relatively rigid but ensure high cleanliness, fitting most PCB cleaning scenarios.

  • Ultrasonic Edge Sealing: Offers softer edges, better for highly sensitive surfaces like optical components, though at a higher cost.

  • Avoid Raw Cut Edges: Unsealed wipes tend to shed lint, posing risk of secondary contamination.

Basis Weight and Size:

  • Basis Weight: Polyester wipes with ≥120g/m² balance absorption and durability. Ultrafine wipes with ≥120g/m² are also recommended for enhanced performance.

  • Size: Common sizes include 4″×4″, 6″×6″, and 9″×9″. Larger wipes (9″) suit broad surface cleaning, while smaller sizes are better for delicate or confined areas. The 9″ size is widely used.

Cleanliness Grade:

  • Choose wipes based on the production environment’s cleanroom class. For example, Class 100 cleanrooms require Class 100 cleanroom wipes.

Additional Features:

  • Anti-Static: Wipes with anti-static properties (often achieved via conductive fibers) prevent static buildup and dust attraction, safeguarding PCB performance. For less stringent needs, solvent-wetting can reduce static.

  • Pre-Wetted Options: Some wipes come pre-impregnated with alcohol (e.g., IPA), reducing on-site spraying. More common internationally than domestically.

2. Proper Usage of Cleanroom Wipes

Pre-Wetting:

  • Use high-purity solvents such as ≥99% isopropyl alcohol (IPA) or ethanol.

  • Ensure uniform wetting via controlled soaking devices to avoid overly wet or dry spots.

Unpacking Procedures:

  • Perform unpacking in Class 1000 or higher cleanroom environments, wearing cleanroom garments, gloves, and masks.

  • Wipe the outer packaging opening with a cleanroom wipe moistened with solvent to prevent external contamination.

Wiping Techniques:

  • Fold wipes to enclose edges internally, preventing lint from edges contacting PCB surfaces—especially important for ultrasonic sealed wipes which can be abrasive.

  • Use unidirectional wiping with light, consistent pressure to avoid redeposition of particles or surface scratching.

  • Adjust wiping force according to PCB surface sensitivity, with extra care on pads or sensitive areas.

Solvent Use:

  • Apply enough solvent to moisten the wipe without dripping to avoid residue from evaporation.

  • Test new solvents on small PCB areas first to confirm compatibility and avoid corrosion.

Storage and Reuse:

  • Seal unused wipes immediately to prevent dust absorption.

  • High-end wipes may be reused after cleaning with ultrapure water (18 MΩ·cm) and drying in a cleanroom; ordinary wipes are generally single-use.

3. Important Precautions

  • Wear anti-static wristbands and ensure grounded workstations to prevent ESD damage to components.

  • Avoid wiping multiple areas with the same wipe to reduce cross-contamination risks.

  • Regularly monitor cleanroom temperature and humidity.

4. Recommended Brands and Models

  • Brands: Preferably YUSTER (domestic) or TEXWIPE (international).

  • Models:

    • K122 Series: 120g basis weight, laser or ultrasonic sealed edges, suitable for PCB boards and applications involving liquids. Available in four sizes.

    • K610 Series: 180g basis weight ultrafine fiber with laser or ultrasonic sealing, excellent absorption for high-precision cleaning.

Summary

For budget-conscious scenarios, 120g laser-cut polyester wipes provide reliable cleaning. For higher requirements and budgets, 180g laser-cut ultrafine fiber wipes offer enhanced absorption and gentler cleaning for delicate PCB surfaces.

Semiconductor Contaminants: Molecular Cleanliness

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As the crown jewel of modern industry, semiconductor manufacturing demands an extraordinarily clean production environment, reaching molecular-level cleanliness standards. With the advancement to 3-nanometer node technology, controlling contaminants during production has become a core factor determining industry competitiveness. This article provides an in-depth analysis of the four major contamination threats faced by the semiconductor industry: particulate contamination, organic contamination, chemical residue contamination, and electrostatic hazards, along with their specific impacts and control measures.

1. Particulate Contamination

Even in a Class 100 cleanroom environment, particles sized 0.5 microns can still cause critical defects. The risks from particulate contamination mainly include:

  • Physical Hazards:

    • Electrostatic carriers: Moving dust particles carry static charges that cause contamination. Static electricity leads to equipment damage and performance degradation, increasing rework and scrap rates, thereby reducing production efficiency and increasing costs.

    • Circuit damage: Particles larger than the circuit spacing can cause shorts. For example, metal microparticles on a 300mm wafer surface can cause line bridging during photolithography, potentially scrapping the entire wafer.

    • Mechanical damage: Hard particles such as residual 0.03 μm aluminum oxide abrasives can scratch wafer surfaces during CMP processes, altering surface roughness and causing lattice defects in subsequent film deposition.

  • Impact on Equipment Reliability:

    • Particulates can cause seal failures in precision equipment joints.

    • Accelerated wear of moving parts due to particulate abrasion.

2. Organic Contamination

Organic silicon contamination is a major issue for process nodes below 28nm, with the following impacts:

  • Organic Silicon Hazards:

    • Oxidative reactions form hard silicate deposits that damage surfaces. Studies show that 1 ppb organic silicon vapor on a 300mm wafer surface can cause transistor threshold voltage shifts of up to 15%.

    • Reduces reliability of rotating machinery.

  • Process Effects:

    • Deteriorates the density of gate oxide layers, impacting device performance.

    • Generates by-products during high-temperature processing that affect product consistency.

3. Chemical Residue Contamination

Metal ion contamination exhibits a cascading amplification effect, especially copper ions with a migration rate up to 1×10^6 cm²/(V·s):

  • Ionic Contamination (Mobility Hazards):

    • Metal ion migration causes device failures.

    • Active ions trigger electrochemical corrosion on metal surfaces.

  • Non-Volatile Residues:

    • Electrolyte residues induce abnormal etching reactions.

    • Compound formation creates hard-to-remove by-products that degrade product quality.

4. Electrostatic Hazards

  • Generation Mechanisms:

    • Charge generation through contact-separation (triboelectric effect).

    • Electrostatic induction from external electric fields.

  • Destructive Mechanisms:

    • Electrostatic attraction or repulsion interferes with precise component placement.

    • Dielectric breakdown occurs when static voltage exceeds IC tolerance limits.

    • Device miniaturization amplifies sensitivity to electrostatic damage.

Conclusion

In semiconductor manufacturing, contamination types often interact synergistically—for example, particles carrying static charges or organic compounds decomposing into chemical residues—forming complex contamination systems. Modern fabs must implement multi-layered contamination control strategies including environmental controls, material purification, process optimization, and electrostatic discharge prevention to ensure stable production and high yield.

Cleanroom Wipe Tests: 7 Key Standards & Insights

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Cleanroom wipes are essential consumables in cleanrooms and high-purity industries such as electronics and pharmaceuticals. Their performance directly affects the cleanliness of production environments and product yield. Currently, multiple testing standards cover aspects such as anti-static properties, particle release, material durability, and sterilization validation. This article systematically summarizes seven mainstream testing standards, explaining their applicable scopes and core requirements, while providing practical interpretation to help enterprises improve product quality and competitiveness.

1. IEST-RP-CC003.4:2011 — Cleanroom Garment System Requirements

Developed by the Institute of Environmental Sciences and Technology (IEST), this standard primarily regulates the production and testing of cleanroom garments and associated fabrics.

  • Material Selection: Woven fabrics preferably use polyester or polyester-carbon composite fibers to reduce particle shedding. Disposable cleanroom garments utilize nonwoven fabrics such as spunbond or meltblown layers.

  • Key Tests:

    • Particle retention rate is evaluated using the Helmke Drum test, focusing on 0.3–0.5 μm particles for cleanliness classification.

    • Sterilization validation must comply with ISO 11137, achieving a sterility assurance level (SAL) of 10⁻⁶.

  • Applications: Suitable for high-cleanliness industries like pharmaceuticals and microelectronics.

2. IEST-RP-CC004.4:2019 — Cleanroom Wiping Materials Evaluation

Focuses on functional testing of wipes, including particle residue and anti-static performance.

  • Particle Residue: Evaluates non-volatile residue (NVR) content via microparticle detection methods such as ASTM E1560 gravimetric analysis.

  • Anti-Static Performance: Requires surface resistivity ≤1×10¹¹ Ω and static decay time ≤2 seconds (per IEC 61340-5-1).

  • Suitability Classification: Recommends wipe types according to cleanroom class (ISO 14644-1), e.g., microfiber wipes for higher-class areas.

3. GB/T 24249-2009 — Anti-Static Cleanroom Fabrics (Chinese National Standard)

Specifies performance requirements for anti-static cleanroom apparel and gloves.

  • Technical Requirements:

    • Surface resistivity range of 1×10⁵ to 1×10⁹ Ω to ensure effective static dissipation.

    • Abrasion resistance tested by Martindale method with mass loss ≤5%.

  • Applications: Electronics, semiconductor, and pharmaceutical cleanroom garments.

4. SJ/T 11480-2014 — Anti-Static Cleanroom Wipes (Electronics Industry Standard)

Targets particle and chemical compatibility requirements for electronics wipes.

  • Tests:

    • Non-volatile residue (NVR) ≤0.1 mg/cm² (ASTM E1560).

    • Extractables must comply with electronics cleaning demands.

  • Edge Sealing: Laser or ultrasonic sealing recommended to minimize fiber shedding.

5. FZ/T 64056-2015 — Cleanroom Wipes (Textile Industry Standard)

Covers woven, knitted, and nonwoven wipes, emphasizing particle release and absorbency.

  • Cleanliness: Suitable for ISO Class 5 (Class 100) cleanrooms with particle release ≤300 particles/m³ (≥0.5 μm).

  • Absorbency: Minimum water absorption of 400 g/m² to ensure cleaning efficiency.

6. Seagate Testing Standard

Seagate’s proprietary testing standards can be referenced by industry participants to meet specific customer requirements.

7. Customer Standards

Customer-specific standards are the most critical quality benchmarks.

  • Regardless of industry norms, meeting customers’ cleanliness class and basis weight requirements is essential for product acceptance.

  • Example: One client shifted from low-cost wipes bought on e-commerce platforms (lacking cleanroom classification) to USTER products with guaranteed cleanroom grades (minimum Class 10,000 for wipes and Class 1,000 for microfiber wipes), resulting in a significant quality improvement.

Summary and Recommendations

  1. Selection Basis: Choose products compliant with relevant cleanroom classes (ISO 14644) and industry needs (electronics, pharmaceuticals).

  2. Quality Control Focus: Monitor particle residue, anti-static properties, durability, and sterilization efficacy regularly.

  3. Future Trends: Standards are evolving towards environmental sustainability (e.g., biodegradable nonwovens) and smart testing (real-time particle monitoring).

USTER is committed to continuously raising cleanroom wipe quality standards to support industries in achieving higher cleanliness levels and improved product yields.

Cleanroom Consumables: LPC Testing for Cleanliness

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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

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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

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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

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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.