Closure Torque

Closure torque testing measures the rotational force required to apply or remove a closure, such as a bottle cap, jar lid, or other sealing component, from its container. This process is essential for ensuring packaging integrity, preventing leaks or contamination, and maintaining ease of opening for the end user.

The correct application torque is vital for achieving a secure seal, while removal torque must balance consumer convenience with safety. In industries such as pharmaceuticals, food and beverage, and personal care, closure torque testing safeguards product quality, extends shelf life, and ensures compliance with regulatory requirements. Without consistent torque control, manufacturers risk leakage during transport, spoilage, or safety concerns, all of which can damage brand reputation and increase operational costs.

Application torque

Application torque is the force used to secure a closure onto a container during the capping process. It directly affects seal integrity, freshness, leakage prevention, and tamper resistance. Insufficient torque may lead to weak sealing, while excessive torque can damage closures or container threads. In high-speed production, consistent application torque is crucial for both quality control and operational efficiency.

Removal torque

Removal torque is the force required to open a closure once applied. It must ensure the packaging remains sealed during distribution but can still be opened by the intended user. For example, pharmaceutical packaging must comply with child-resistant requirements while remaining accessible for adults. Removal torque can be affected by storage conditions, material relaxation, or tamper-evident features.

Bridge torque and slip torque

Bridge torque is the force needed to break bridges on tamper-evident closures before the cap can be removed. Slip torque is the point at which a closure rotates without unscrewing due to internal slippage. Both are critical indicators of tamper evidence and closure performance, especially in safety-sensitive products such as over-the-counter medicines, beverages with safety seals, and hazardous chemical packaging.

Manual vs motorised torque testers

Manual torque testers are suited to spot checks or lower-volume testing. They are portable, easy to use, and cost-effective but rely heavily on operator consistency, making results more variable.

Motorised torque testers automate application and removal, providing higher accuracy, repeatability, and control over speed. They are ideal for high-volume production and testing to tight tolerances.

Best practices for accurate measurement

• Calibrate equipment regularly to maintain accuracy.
• Secure fixtures and samples to prevent slippage or misalignment.
• Simulate real-use conditions where possible, including temperature and humidity.
• Standardise test speeds to avoid inconsistent results.

Following these practices minimises variability and ensures reliable quality control and compliance data.

ASTM D2063 defines methods for determining application and removal torque for closures. It specifies equipment requirements, sample preparation, and testing procedures for repeatable, accurate results.

Other relevant standards include:

• ISO 13379 - guidance on testing plastic closures.
• ISO 17480 - accessibility criteria for consumer packaging.

Many regulations for child-resistant or tamper-evident packaging also require torque testing to demonstrate compliance. Meeting these standards ensures safety, usability, and consistent performance.

Precision torque measurement systems

Mecmesin offers high-resolution torque testers such as the OmniTest and MultiTest-dV, combined with VectorPro software for data capture, analysis, and compliance reporting. These systems deliver accurate, repeatable measurements across a wide variety of closure types.

Versatile testing capability

Mecmesin torque testers can assess:

• Tamper-evident closures for bridge torque performance.
• Child-resistant designs for compliance with opening force requirements.
• Slip torque in closures to assess sealing and usability.
• Caps made from plastic, metal, or composite materials across industries from food and beverage to cosmetics and pharmaceuticals.

Compliance-ready and custom solutions

All Mecmesin systems are designed to meet or exceed ASTM, ISO, and industry-specific requirements. Modular fixtures allow for testing of closures with varying geometries and sizes, ensuring accurate, secure testing.

Global service and support

Mecmesin provides accredited calibration, technical support, and training worldwide. Bespoke fixture design is available for unique packaging formats, ensuring consistent and standards-compliant testing.

Closure torque testing is vital for ensuring that packaging remains secure, protects contents, and is user-friendly. By selecting the correct testing equipment and applying industry best practice, manufacturers can reduce failures, improve customer satisfaction, and maintain compliance.

If you need expert advice on closure torque testing or want a tailored demonstration for your packaging, contact Mecmesin for guidance on selecting the most accurate and standards-compliant solution for your needs.