New hybrid thickness measurement systems combine confocal differential metrology and spectral interferometry micro-head sensors to deliver unmatched precision in multilayer film and laminate inspection—inline and in real time.
Together, these systems offer a breakthrough metrology platform for high-value packaging applications.
Confocal Differential Measurement: Trusted Accuracy for Total Film Control
Confocal laser sensors focus light through a pinhole to measure the distance to a surface with extreme precision. When used in opposing-pair configurations, they create a differential measurement system capable of resolving the total thickness of transparent, translucent, or opaque films with sub-micron accuracy—in real time and without contact.
Applications Include:
- Real-time thickness control during coextrusion or lamination
- Closed-loop feedback to process controllers for automatic adjustment
- Process feedback for gauge reduction in barrier films and multi-layer structures
- Detecting curl, voids, and seal non-uniformity in multilayer constructions
Confocal sensors are especially effective in high-speed, roll-to-roll systems where wear-free, inline operation is critical. However, while they excel at total thickness measurement, they do not inherently resolve individual internal layers—a growing need in modern multi-material packaging designs.
Bold’s 3DS1430 Confocal Thickness Measurement System
___________________________________________________________________
Spectral Interferometry Micro-Heads: Layer-Resolved Precision
Graphic by Keyence Corporation
Now emerging in the marketplace is a revolutionary sensor: a spectral interferometry-based micro-head, engineered to measure individual layer thicknesses, internal gaps, and material transitions within multilayer films.
This technology uses a broadband light source to generate interference fringes from internal reflections. These fringes are analyzed to determine optical path differences, translating into physical thickness measurements at nanometer scale.
What sets this system apart is its micro-head architecture, making it:
- Easy to integrate into tight machine envelopes
- Ideal for multi-sensor arrays across wide webs
- Capable of resolving sub-surface and surface thickness simultaneously
Use Cases Include:
- Monitoring barrier coatings (EVOH, SiOx, AlOx) in food packaging
- Detecting adhesive uniformity in medical laminates
- Mapping warpage and flatness in thin foils and flexible electronics
- Identifying delamination risks or voids in aerospace insulation films
Bold Laser Automation: Modular Integration for Real-World Production
Recognizing the need to bring these cutting-edge sensor technologies into real manufacturing environments, Bold Laser Automation of Bedford, New Hampshire has developed a suite of modular tooling systems and calibration methods. Bold’s expertise lies in enabling the seamless integration of confocal and spectral interferometry sensors into both existing production lines and standalone offline QA/QC inspection platforms. Their solutions are designed for the demands of real-world production, ensuring reliability and ease of use.
Bold’s solutions include:
- Custom sensor mounting frames with precision XYZ adjustment
- Roll-to-roll and sheet-fed sensor bridges for retrofitting into extrusion, lamination, and coating systems
- Offline inspection stations for lab-based quality control with full profile mapping
- Advanced calibration routines, including traceable optical standards
- Software integration with MES, SCADA, and SPC platforms for real-time statistical process control (SPC)
Bold’s platforms can deliver closed-loop feedback for real-time thickness control during coextrusion and lamination, automatically optimizing processes. This capability supports gauge reduction strategies in barrier films and laminates, enabling customers to lower material consumption while maintaining or enhancing package performance.
A Lab-Based Dual-Opposing Confocal Laser Thickness Measurement System (200 mm substrate)
Industry Applications: Smart Sensing for Smarter Packaging
Medical Device Packaging
Inline verification of adhesive, film, and coating thickness ensures sterile barrier integrity and process compliance. Combined systems prevent weak seals and contamination and confirm pouch consistency where even minor variations can impact performance and patient safety.
Food & Consumer Packaging
Manufacturers can optimize high-barrier films by monitoring internal layers for thickness drift—enabling material savings and improving seal quality while reducing scrap rates. Detecting subtle variations that can lead to oxygen or moisture ingress, such as in EVOH or SiOx barrier layers in flexible food packaging, extends shelf life and reduces food waste.
Aerospace & Thermal Insulation
Multi-ply laminates used in thermal shielding and EMI protection benefit from warpage and ply uniformity mapping, ensuring performance in extreme conditions. Mapping warpage and delamination in multi-ply thermal insulation blankets used in aircraft or spacecraft ensures consistent performance under extreme temperature variations. Verifying the precise layer thickness of materials used for EMI shielding in avionics, ensures proper function and prevents electronic interference.
Microelectronics & Flexible Circuits
Sub-micron dielectric, adhesive, or encapsulant layer thicknesses can be measured without contact or risk of damage, enhancing process control for printed electronics and hybrid circuits. For example, measuring the thickness and uniformity of dielectric layers in flexible printed circuit boards (PCBs) ensures proper insulation and can prevent shorts.
Also, monitoring the thickness and consistency of encapsulant layers used to protect sensitive electronic components in flexible displays or wearable devices enhances device performance and reliability and means non-destructive inspection of delicate structures.
Inline Control, Sustainability, and Smart Manufacturing
These precision measurement tools directly support next-generation packaging objectives:
- Material reduction through minimum viable thickness control. Material waste due to poor thickness control leads to excessive material use (going above minimum viable thickness “just to be safe”) or significant scrap due to defects like delamination or voids.
- Elimination of Product Failures and Returns because consistent layer thickness can prevent barrier defects (resulting in food spoilage or medical device contamination) which in turn can lead to product recalls, warranty claims, and harm to brand name.
- Waste minimization by detecting defects early in production and reducing bottlenecks and downtime. Manual inspection methods can lead to a slowdown in production, require stopping lines, or not receiving real-time feedback to prevent issues before they become widespread.
- Energy savings through improved first-pass yields and process stability.
- Digital manufacturing compliance for traceability and Industry 4.0 readiness. For industries like medical or aerospace, failing to meet strict thickness specifications can lead to production halts and even costly fines.
- Staying Competitive through technology results in higher yields, lower costs, and superior product quality, putting the competition at a significant disadvantage while struggling to keep pace.
Through Bold Laser Automation’s modular integration approach, manufacturers can seamlessly deploy this high-precision technology—whether upgrading active production lines or establishing new quality assurance protocols.
Conclusion: Packaging Metrology Enters the Micron Era
The packaging industry is entering a new phase of precision—where sub-micron thickness control, internal layer mapping, and real-time process feedback are critical competitive advantages.
By combining confocal laser differential thickness systems with spectral interferometry-based micro-head sensors—and enabling deployment through Bold Laser Automation’s advanced modular platforms—converters, film producers, and packaging companies can achieve new levels of quality, efficiency, and material savings.
Importantly, Bold Laser Automation has active installations across the United States, serving leading manufacturers in packaging, medical, aerospace, and microelectronics sectors.
To explore how these advanced metrology solutions can transform your packaging operations, fill out our Contact form on the website or call us at (603) 413-5601.
This integrated metrology approach redefines what’s possible in thin-film and multilayer packaging—inline, offline, and everywhere precision matters most.
Recent Comments