Case-study | Glove Former Surface Area Blue Light Scan

Surface area measurement is used in the calculation of cleaning validation protocols for medical devices. Knowing the device's surface area allows manufacturers to calculate sterilization or disinfection doses and model irradiation appropriately. Metrics like residual soil per cm², sterilant contact modeling, and exposure dose modeling rely on accurate knowledge of surface geometry. Surface area data can also help manufacturers comply with ISO and FDA standards, including ISO 17664-1, which specifies requirements for the processing of critical or semi-critical medical devices intended for sterilization. 3D scanning is embedded in the surface area calculation process. Nel Pretech industrial CT scanning has long been a value-added service for internal and external sterilization validation. However, blue-light structured-light scanning is an accurate, cost-efficient alternative when only external surface measurements are needed. Blue-light scanning can capture millions of points per scan for precise, reliable surface measurements to enhance cleaning and regulatory validation processes.

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Why Surface Area Matters in Medical Device Cleaning and Sterilization

Residual soil is the amount of organic, biological, or simulated matter, visible or non-visible, left on a device after the sterilization process or simulation. Post-processing calculation is expressed in terms of the total soil mass divided by the total surface area of the device. The medical device sterilization process is used for safety purposes at the point of use and to eliminate contamination during the manufacturing process. Having current surface area data can help demonstrate the efficacy of your validation process. If the processing of your medical devices requires ISO or FDA compliance, developing proper cleaning protocols requires surface area data to report residual soil on test devices.   

How Surface-Area Data Supports Sterilization and Cleaning Validation

• Prevent over-dilution: determine detergent, disinfectant, or solvent volume
• Eliminate guesswork in soil application and recovery: use measurable and traceable geometric data during cleaning validation or worst-case testing
• Create a digital baseline: repeatable datasets for process changes and mold revisions
• Strengthen compliance and regulatory documentation: accurate surface area data improves simulations and strengthens your technical justification 

Accurate Surface-Area Measurement of Glove Formers Using Blue-Light Scanning

A glove former is typically a ceramic mold in the shape of a hand used in high-volume medical glove manufacturing. Ceramic is used because of its durability in repeated exposure to chemicals and heat. The former determines the glove size, shape, thickness, and texture as it is dipped in latex or nitrile.

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Blue-light scanning is a modernized version of white-light scanning. The blue light offers a narrower wavelength because it only represents one color. White light encompasses all colors and thus has a wider wavelength. The narrow blue light wavelength means better filtering of interference from the surrounding ambient light. Blue light scanners are not as easily influenced by temperature fluctuations, either.

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Blue-light scanning is used for line-of-sight and is ideal for external geometries on most medical devices. At Nel PreTech Corporation, we use an ATOS Q 3D scanner with submillimeter accuracy.

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ATOS Q Specs:

• It takes 8 million points per scan
• LED light source 
• Measuring area is 100x70-500x370 [mm²] 
• Point distance is 0.04-0.15 [mm]

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Limitations of blue-light scanning: 

• Difficulty with clear or reflective surfaces (may require additional preparation with specialized scanning sprays)
• Cannot capture internal geometries (holes can be measured up to 4x the diameter) 

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The Client’s Challenge

• The manufacturer needed accurate surface-area data to support cleaning and sterilization validation of their glove former.
• Lack of CAD models or legacy engineering files made manual calculations impossible or unreliable.

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Nel Pretech’s Approach

Blue-light structured-light scanning was used to determine the surface area of a ceramic glove former (or mold) used in the manufacturing process of medical gloves. The blue-light method incorporated a calibrated pattern of blue light projected onto the object. When the light washed over the surface of the glove former, it was distorted by the shape, curves, and edges. The distorted light was reflected to the scanner and was picked up by stereographic camera lenses. It took approximately 36 captures per part to build a complete 3D image. Nel PreTech used ATOS Professional scanning software to gather the data. The scans or frames were aligned and processed to form the seamless 3D model. The uncertainty of the 350 measurement volume was 30 microns (0.03mm). 

Why Blue-Light Structured-Light Scanning Is Ideal for External Surfaces

1. High-resolution measurement of curves, contours, and textures on ceramic, aluminum, or composite formers.
2. No need for internal geometry capture using CT scanning when calculating external surface area for sterilization or cleaning protocols on formers.
3. Fast scanning & repeatability = reliable results.
4. Non-contact and non-destructive scanning is ideal for production tooling that cannot be cut.

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Problems Nel PreTech Helps Manufacturers Solve

If a manufacturer is missing legacy CAD files or has outdated manufacturing drawings, Nel PreTech uses 3D scanning to reconstruct tooling. We provide precise surface area values to ensure accurate dosage and soil applications. The speed of blue-light scanning and non-essential fixturing saves time and helps medical manufacturers get back to producing. 3D models and data comparison allow for the monitoring of tool wear or changes over time. With accurate measurements, medical device companies can make data-driven decisions and keep up with regulatory compliance.

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Data-Driven Sterilization Confidence for Medical Device Manufacturers

3D data, such as the surface measurements blue-light scanning can provide, is modernizing medical manufacturing operations. Verifiable surface area measurements support cleaning, sterilization, maintenance, and regulatory compliance, and companies cannot risk anything less. Our customers trust our ISO/IEC 17025 A2LA-accredited methods. We encourage you to find out why. 

Reach out to our expert engineers for a free consultation or to submit a request for quote. 

Read our article on surface area calculation for medical devices using industrial CT scanning if you’d like to learn more about how we determine internal surface areas on complex parts. 

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FAQ

Q: Why does surface area matter for cleaning validation? 

A: All residual soil in the extractant from a test device is divided across the total device surface area tested to evaluate the soil per surface area (ex. μg of soil per cm² of surface area). STERIS AST

Q: Can blue-light scanning replace CT for formers/molds? 

A: Yes, if only seeking external geometry. CT is still needed for internal geometries.

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Q: How accurate are blue-light scans for surface area? 

A: Accuracy varies widely between scanners. The ATOS Q that NPC uses quotes accuracy between a tenth of a thou and 2 thou. Blue light and triple scan technologies, along with advanced software, contribute to the high accuracy of these machines.

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References

1. Steris - Reusable Medical Device Cleaning Validation: Soiling Considerations
2. ISO 17664-1:2021 - Processing of health care products — Information to be provided by the medical device manufacturer for the processing of medical devices

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