X-ray Inspection System for Bottles, Jars and Cans: Contaminant and Fill-Level Detection

Food packed in bottles, jars and cans presents some of the most demanding inspection challenges in the food industry. Foreign materials may be hidden by metal packaging, thick glass, container bottoms, screw threads, closures or densely packed products. Liquid and semi-liquid foods can create additional variations in X-ray images, while modern production lines require inspection and rejection to take place at high speed.

Techik's X-ray inspection system for bottles, jars and cans is designed for the non-destructive inspection of sealed food products. Depending on the selected configuration, it can inspect products for foreign contaminants and filling-level deviations while supporting automated rejection of suspected packages.

Available inspection configurations include inclined downward, dual-beam, triple-beam and split triple-beam X-ray systems. These options allow manufacturers to select an imaging arrangement based on the container, product, target contaminants and production requirements.

Why Are Bottles, Jars and Cans Difficult to Inspect?

Metal cans, glass jars and bottles protect food during processing, transportation and storage. However, the same packaging structures that protect the product can interfere with contaminant detection.

A metal can creates a strong X-ray background. Pull tabs, seams, sidewalls, lids and curved bottoms may overlap with metal fragments inside the product. Detecting metal inside metal packaging therefore requires an inspection system capable of distinguishing foreign objects from normal package features.

Glass containers present a different challenge. A glass fragment inside a glass bottle may have characteristics similar to those of the container itself. If the fragment is positioned close to the bottle wall, neck, bottom or screw mouth, it can overlap with the glass structure in an inspection image.

Other factors also affect inspection performance:

- Irregular container shapes

- Thick or curved container bottoms

- Metal caps and closures

- Dense or viscous food products

- Mixed liquid and solid ingredients

- Natural variations in product distribution

- Small or irregularly shaped contaminants

- High production speeds

An effective bottle, jar and can inspection solution must consider the package, the product and the likely contaminant at the same time.

How Does a Food X-ray Inspection System Work?

As a sealed container travels through the inspection machine, an X-ray beam passes through the package and product. Materials absorb different amounts of X-ray energy according to factors such as density, thickness and composition.

A detector receives the remaining energy and converts it into an inspection image. Image-processing software analyzes the image for unusual high-density features or other predefined quality deviations.

When the system identifies a suspected contaminant or nonconforming package, it can send a signal to the production line's rejection mechanism. A high-speed pusher or multi-segment rejection system can then remove the affected container from the accepted product flow.

This process takes place without opening or damaging the package, making X-ray inspection suitable for continuous production lines.

Glass-in-Glass Detection for Bottled and Jarred Foods

Broken glass can enter a product if a bottle or jar is damaged during manufacturing, washing, transportation, filling or sealing. Glass-in-glass detection is difficult because the contaminant and the package are made from similar material.

The most challenging areas often include:

- The bottom of the bottle or jar

- Bottom corners

- The container wall

- The neck and shoulder

- Screw-mouth areas

- Embossed or irregular glass structures

A fragment may also be flat or irregular, making it more visible from one direction than another. For this reason, the angle of the X-ray beam can have a significant effect on inspection performance.

Techik offers different optical-path and imaging configurations for bottled and jarred food applications. Multi-angle systems provide more than one view of the container, helping reduce blind areas caused by contaminant orientation or overlap with the package.

Potential applications include bottled vegetables, pickles, sauces, baby food, coffee, fruit products, beverages, cooking wine and other foods packed in glass containers.

Actual detection performance depends on the glass fragment's size, thickness, shape, position and orientation, as well as the bottle design and product density. Representative sample testing should therefore be completed before the final system configuration is selected.

Metal-in-Metal Detection for Canned Products

Metal contamination may originate from worn production equipment, damaged processing tools, broken screens, maintenance activities or incoming raw materials. Once a metal fragment enters a metal can, conventional metal detection may be restricted by the conductive package.

X-ray inspection offers a way to examine the contents of a sealed metal can. However, difficult areas remain around the pull tab, lid, seam, sidewall, edge press and bottom.

Techik's system combines specialized imaging arrangements with customized intelligent algorithms. The objective is to distinguish suspicious foreign materials from normal can structures while maintaining stable inspection on a production line.

The solution can be considered for products such as:

- Canned meat

- Canned fish and seafood

- Canned vegetables

- Canned fruit

- Canned sauces

- Canned pet food

- Canned milk powder

- Ready-to-eat canned meals

Testing should use real products and relevant contaminants because the result can be influenced by the can dimensions, product density, contaminant position and conveyor speed.

Inclined Downward X-ray Inspection

An inclined downward X-ray system directs the beam through the container at a downward angle. This arrangement is intended to improve inspection coverage in areas that may be difficult for a conventional vertical beam.

The inspection range can be adjusted to suit different container heights and dimensions. This makes the configuration useful for production environments that handle several bottle, jar or can formats.

The inclined downward system is particularly relevant when contaminants may sink to the bottom of the container. Examples include glass fragments, stones, metal pieces or other relatively dense materials in liquid and semi-liquid products.

Depending on the application, the system can also inspect the filling level while checking for foreign contaminants.

Dual-Beam and Multi-Beam X-ray Inspection

A contaminant may be difficult to identify from a single angle. Flat glass fragments, wires and irregular foreign objects can produce different image characteristics when viewed from different directions.

Dual-beam and multi-beam X-ray configurations address this challenge by creating multiple views of the same container.

A dual-beam system uses two imaging paths to inspect the product from different angles. This can reduce blind areas and improve the stability of inspection for irregular contaminants.

Triple-beam and split triple-beam systems provide additional views. They may be suitable for applications where the container has complex structures or where contaminants can be distributed across the top, middle and bottom areas.

The most appropriate configuration depends on:

- Container material and shape

- Bottom structure

- Product type and density

- Target contaminant

- Required inspection sensitivity

- Production speed

- Available installation space

More imaging angles do not automatically guarantee the same result for every product. Application testing remains necessary to determine whether a single-beam, dual-beam or triple-beam arrangement is the appropriate choice.

Simultaneous Contaminant and Fill-Level Inspection

In addition to foreign-body detection, Techik's bottle, jar and can X-ray inspection system can be configured to inspect filling levels.

Underfilling can create regulatory, commercial and customer satisfaction problems. Overfilling increases product giveaway and may interfere with the sealing process. An incorrect ratio of solid ingredients to liquid may also affect product consistency.

X-ray inspection can evaluate the internal contents of containers that are opaque or difficult to inspect with a conventional camera. Potential checks include:

- Low fill level

- Excessive fill level

- Missing contents

- Significant filling deviations

- Abnormal distribution of ingredients

The system can perform fill-level and contaminant inspection during the same pass, helping manufacturers consolidate quality checks without adding a separate destructive inspection step.

The achievable fill-level accuracy depends on the product, package and normal process variation. Products containing mixed solids and liquids should be tested under realistic production conditions.

High-Resolution Detector and Intelligent Algorithms

Detector resolution influences the amount of image detail available to the inspection software. The Techik product page describes a high-resolution detector designed to provide improved exposure performance compared with a standard 0.4 mm detector.

More detailed images can support the inspection of small contaminants and complex package areas. However, image resolution is only one part of the overall system.

The inspection algorithm must also distinguish contaminants from normal variations such as:

- Product movement

- Ingredient overlap

- Uneven filling

- Container edges

- Caps and closures

- Pull tabs and seams

- Differences between product batches

Techik provides customized intelligent algorithms to support inspection sensitivity and stability for specific applications. Software can be adapted according to the product, container and inspection objective.

High-Speed Automatic Rejection

Detecting an abnormality is only useful if the affected package can be removed reliably. The system can be equipped with a high-speed pusher rejecter or a multi-segment rejection mechanism.

The reject solution should match the container's:

- Weight

- Shape

- Stability

- Material

- Production speed

- Spacing on the conveyor

Stable conveying is particularly important for glass bottles and tall containers. Excessive movement can affect both the X-ray image and the rejection process. Production-line integration should therefore consider guides, conveyor transitions, package spacing and reject confirmation.

Production-Line Integration and Operator Controls

The X-ray inspection system is designed for connection with existing production lines. Integration requirements should be evaluated before installation, including conveyor height, line speed, available floor space, upstream spacing and downstream reject collection.

Operator features described for the system include:

- A large touchscreen

- Multiple language options

- An automatic monitoring interface

- Ethernet connectivity

- USB connectivity

- Updated or customized software

- Remote parameter-setting capability

A user-friendly interface can help operators manage product settings, monitor inspection results and respond to alarms. Access levels and operating procedures should be configured according to the manufacturer's quality management requirements.

Applications in the Canned and Bottled Food Industry

The system can be evaluated for a wide range of packaged food and beverage products, including:

- Canned meat and luncheon meat

- Canned fish and seafood

- Canned vegetables and fruit

- Bottled pickles

- Sauces and condiments

- Baby food

- Milk powder

- Coffee products

- Pet food

- Beverages and liquid foods

Many of these are ready-to-eat products with demanding food safety requirements. Potential contaminants may come from agricultural raw materials, damaged equipment, broken screens, packaging materials, manual handling or the surrounding production environment.

Finished-package X-ray inspection provides an important control after filling and sealing. For a more complete approach, it can be combined with raw-material optical sorting and bulk X-ray inspection before the packaging stage.

How to Select the Right X-ray Configuration

Before choosing an X-ray inspection system for bottles, jars or cans, manufacturers should provide detailed application information.

Important factors include:

1. Container material, dimensions and shape  

2. Product density and consistency  

3. Liquid, solid or mixed-product characteristics  

4. Target contaminants and required sizes  

5. Expected contaminant locations  

6. Production-line speed  

7. Filling-level inspection requirements  

8. Available floor space  

9. Preferred rejection method  

10. Cleaning and environmental requirements  

Representative testing should include normal products, different batches, actual container variations and relevant contaminant samples. This helps determine the suitable imaging configuration, detector, software parameters and reject mechanism.

A Practical Solution for Sealed Food Inspection

Bottles, jars and cans protect food effectively, but their structures can make internal inspection difficult. Glass-in-glass detection, metal-in-metal detection, bottom-area inspection and fill-level verification all require a solution designed around the actual production application.

Techik offers inclined downward, dual-beam, triple-beam and split triple-beam X-ray configurations for different container and product requirements. High-resolution imaging, customized intelligent algorithms and automated rejection support continuous inspection of sealed products.

Food manufacturers planning a new inspection project can submit product details, container dimensions, target contaminants and line-speed requirements to Techik. Application testing can then be used to recommend a suitable X-ray inspection solution for the production line.