Basis Weight Measurement: The Right Technology for Every Application

Beta transmission is one of the most established methods for industrial basis weight measurement. In this process, energetic beta particles pass through the material. As the radiation penetrates the web, its intensity is attenuated in proportion to the amount of material present.

Because the measurement is directly related to mass per unit area, this technology provides extremely accurate and highly reproducible results. Furthermore, the measurement is largely independent of colour, surface characteristics and optical properties, making it particularly suitable for applications requiring maximum precision and long-term stability.

Typical applications include the production of nonwovens, technical textiles, filtration media, battery separators, coated products, composites, as well as paper and board products. Online measurement is often performed immediately after web formation or following coating and finishing processes in order to continuously monitor basis weight across the entire web width. When combined with traversing scanning systems, a detailed basis weight profile can be generated and used for automatic profile control.

Benefits

• Exceptional measurement accuracy
• Direct mass measurement
• Independent of colour and surface characteristics
• Excellent long-term stability
• Ideal for closed-loop control and quality assurance

X-ray-based measurement systems utilise the interaction between X-ray radiation and matter. As the radiation passes through the material, it is attenuated according to the material mass, allowing the basis weight to be determined with high accuracy.

Modern systems use electronically generated X-rays and therefore do not require radioactive isotopes. Depending on the application, they can provide additional information on material composition, layer distribution or filler content alongside the overall basis weight measurement.

This technology is widely used in the production of films, composites, glass fibre materials, building materials, coated products, battery electrodes, nonwovens, as well as paper and board. In addition to conventional grammage measurement, certain systems can also analyse coating weight, material distribution and individual material components.

Typical installation points include extrusion lines, coating stations, calenders and laminating processes, where precise monitoring of basis weight, thickness and material distribution is essential. In modern production environments, X-ray technology frequently forms the basis for closed-loop basis weight control systems.

Benefits

• High accuracy across a wide basis weight range
• Suitable for both lightweight and heavy materials
• No radioactive sources required
• Capability to analyse specific material components
• Well suited for modern data-driven manufacturing

Near-infrared (NIR) technology is based on the ability of specific materials to absorb infrared light at defined wavelengths. By analysing reflected or transmitted light, conclusions can be drawn about basis weight, moisture content and material composition.

This technology is particularly suitable for products with a relatively consistent composition where moisture represents an additional critical quality parameter alongside grammage.

Typical applications include the production of nonwovens, textiles, coatings, films, composite materials, as well as numerous drying and finishing processes. It is also used in the paper and board industry for monitoring basis weight and moisture.

Sensors are commonly installed downstream of dryers, coating units, impregnation systems or immediately before winding. Since moisture content and basis weight are often closely related, NIR technology provides highly effective real-time measurement and process monitoring across the entire web.

Benefits

• Simultaneous measurement of basis weight and moisture
• Non-contact and wear-free operation
• Rapid response times
• Low maintenance requirements
• Highly cost-effective for continuous production lines

NIR spectroscopy extends conventional infrared measurement by analysing a much broader spectral range. This creates a unique material “fingerprint” from which multiple quality parameters can be determined simultaneously.

In addition to basis weight and moisture, the technology can be used to measure coating weights, resin content, additives and material blends, depending on the application. As a result, it provides significantly more process information than traditional single-parameter measurement systems.

Typical applications include extrusion and coating lines, film production, battery coating processes, composite manufacturing, technical textiles and other high-performance materials with complex formulations. The technology is also employed in paper and board production.

NIR spectroscopy is particularly valuable in production stages where coating weight, raw material composition, material homogeneity and moisture content directly influence final product quality. The extensive measurement data supports continuous web quality control and data-driven process optimisation.

Benefits

• Multiple quality parameters measured with a single sensor
• High level of material information
• Analysis of material composition and coatings
• Rapid process optimisation through comprehensive real-time data
• Ideal for Industry 4.0 and advanced manufacturing environments

Optical measurement systems use camera-based or optoelectronic sensors to analyse material structure. Typical parameters include thread density, stitch density, fabric structure and surface characteristics.

Unlike radiation-based technologies, these systems do not directly measure mass. Instead, they evaluate structural parameters that are closely related to basis weight. In addition to grammage measurement, they can simultaneously monitor thread counts, stitch counts, fabric appearance and other important quality characteristics. This enables comprehensive online inspection and quality assessment of textile webs.

The technology is primarily used in the textile industry, particularly for the production of woven fabrics, knitted fabrics, warp-knitted materials, functional textiles and technical textiles, as well as throughout textile finishing operations.

Systems are typically installed downstream of weaving or knitting machines, on stenters, compacting ranges, sanforising lines and other finishing equipment. There they provide continuous real-time quality monitoring and process control.

Benefits

• Simultaneous monitoring of basis weight and fabric structure
• Early detection of weaving, knitting and finishing defects
• No radiation sources required
• Additional quality information through thread and stitch density analysis
• Particularly suitable for textile manufacturing processes