Top-Load (Column Crush)

Top-load testing, also known as column crush testing, is a method used to evaluate the ability of a packaging component to withstand a vertical compressive force without deforming or failing. In its most common form, the test involves applying a controlled load from the top of the specimen, often a bottle, jar, rigid tray or similar container, until it either reaches a specified deformation or fails structurally.

A typical test setup consists of a motorised vertical test stand, a compression platen, a calibrated load cell to measure force, and alignment fixtures to ensure the load is applied evenly along the container’s vertical axis. The objective is to replicate the compressive forces that packaging might encounter during capping, stacking, transportation or storage.

While related to other compression tests such as box crush testing, top-load testing is specifically concerned with columnar strength rather than surface or edge crush. This makes it particularly relevant for rigid or semi-rigid containers where axial load performance is critical to maintaining product integrity and safety.

Standards such as ASTM D2659, EN 22872 and ISBT PTC-0002 define procedures and performance benchmarks for conducting these tests on packaging materials, ensuring results are repeatable and comparable across testing environments.

Top-load testing plays a critical role in packaging design, quality assurance and compliance. It helps to:

• Verify that containers can withstand compressive forces during capping, where closure torque may generate significant axial pressure. For example, PET beverage bottles may need to resist 200 to 400 N during the capping process.
• Ensure packaging maintains integrity during stacking in storage or transit, preventing deformation or collapse.
• Support lightweighting initiatives by enabling manufacturers to reduce material use without compromising performance.
• Prevent costly product damage or safety hazards caused by packaging failure under load.
• Reduce waste by identifying design or manufacturing issues early in the production cycle.

Industries such as food and beverage, household goods, medical packaging and sustainable packaging all rely on top-load testing to validate product safety, enhance consumer satisfaction and comply with sector-specific standards.

Equipment and setup

The essential equipment for a top-load test includes:

• Vertical motorised test stand to apply a compressive force at a controlled rate.
• Compression platen or fixtures to distribute force evenly across the specimen’s top surface.
• Load cell to measure the applied force accurately.
• Alignment guides and container supports to ensure the sample remains centred and stable.

Speed control is crucial. Test standards specify the rate at which the load should be applied to simulate real-world conditions. For example, bottle testing often requires a slow, steady force application to mimic capping or stacking pressures.

Step-by-step method

• Condition the specimens to standard temperature and humidity to ensure consistent results.
• Place the specimen on the test platform or support fixture, ensuring it is aligned correctly under the compression platen.
• Set the test parameters in the control software, including load application speed and endpoint criteria.
• Apply the load vertically at the specified rate until failure or a predetermined deformation limit is reached.
• Record the peak load and deformation values via the software for analysis.
• Repeat the test across multiple specimens to assess repeatability and statistical reliability.

Modern systems often integrate with advanced control software, allowing for automated data capture, live plotting of force-deformation curves and immediate pass or fail determination against set criteria.

Vertical load and axial resistance expertise

Mecmesin offers dedicated axial load test systems widely used for PET bottles, rigid trays and bio-based packaging materials such as PLA and rPET. Systems such as the OmniTest and MultiTest-dV are designed to deliver precise, repeatable results for quality control, research and production monitoring.

Standards-compliant and configurable

Mecmesin’s equipment supports key industry standards including ASTM D2659, EN 22872 and ISBT PTC-0002. Test frames and fixtures can be configured to suit a wide range of packaging types and geometries, from small pharmaceutical vials to large beverage bottles.

Precision equipment and smart software

Mecmesin’s test stands, combined with high-accuracy load cells, can measure forces from a few newtons to several kilonewtons. The VectorPro software platform enables programmable routines, real-time graphing, automated pass or fail analysis and secure data export to meet compliance and auditing requirements.

Global technical support

Beyond the equipment, Mecmesin provides pre-sales consultancy, custom fixture design, calibration services, operator training and worldwide technical support. This ensures that test systems are not only installed correctly but continue to operate at optimal performance over their service life.

ASTM D2659

Specifies the method for determining the column crush resistance of blown thermoplastic containers. It defines conditioning, alignment and load application parameters to ensure reproducible results.

EN 22872

Outlines the procedure for vertical compression testing of packaging and closures. Applicable to a wide range of container types and supports international quality compliance.

ISBT PTC-0002

A voluntary method established by the International Society of Beverage Technologists. Provides guidelines for PET bottle axial resistance benchmarking, particularly within the beverage industry.

Plastic bottles and closures

In beverage and household product manufacturing, top-load testing is essential to confirm that bottles can endure the capping process without deforming. It also verifies stacking strength for palletised transport. Torque retention testing is often conducted alongside top-load testing to ensure closures remain secure over time.

PLA and recyclable materials

Sustainable packaging materials such as PLA and recycled PET have different mechanical properties compared to traditional plastics. Top-load testing ensures these alternatives meet performance requirements while supporting environmental goals.

Medical packaging systems

Rigid medical trays, blister packs and sterile containers must resist deformation to prevent contamination and maintain safety. Top-load testing helps verify that such packaging can withstand the vertical forces encountered in storage, transport and handling.

Top-load testing provides a vital measure of packaging performance, helping engineers and quality teams optimise designs, comply with regulations and ensure product safety. Mecmesin offers tailored solutions, from standard test frames to custom fixtures and software configurations, backed by global technical support. For expert guidance in selecting the right system for your application, speak to an expert at Mecmesin.