Jewellery testing to tensile strength standards for safety and durability

Case study

Tensile strength testing of a children's bracelet

Raw material specimen tensile test to jewellery manufacture standards

Solution

Software-controlled tensile tester
Selection of hook probes, vice and bollard grips

Benefits

Accurate results to optimise for safety compliance and durability
Repeatable semi-automated testing to international standards
Interchangeable fixtures enable the testing of all jewellery product designs and raw materials with the same system

Requirement

From necklaces and rings to bracelets and earrings, manufacturers and importers of both high-end fashion and costume jewellery need to test for mechanical strength to ensure the safety and quality of their products.

Knowledge of the mechanical properties of alloys, such as gold-copper, platinum-copper and platinum-ruthenium, is essential when determining the ease with which they can be formed into jewellery and their strength and durability when worn.

Stringent safety requirements are imposed, especially for children's jewellery; with Europe, USA, Canada, Japan and China all having established regulations and standards for products sold in their markets.

ASTM F2999 provides specific safety specifications for adult jewellery whilst ASTM F2923 covers children’s jewellery. In Europe EN71-1, although not specifically for children’s jewellery, is widely adopted as a key safety standard. Additionally, many major retailers enforce their own test standards to ensure the items sold meet strict quality and performance requirements.

Solution

A common test amongst all standards is the pull test to check that a pre-determined tension force does not cause attachments and small parts to become detached or broken and potentially become a choking hazard for children. ASTM F2923 even stipulates that jewellery worn around the neck, must break under tension with a force of 15 pounds or more, in order to prevent strangulation.

Testing a necklace or bracelet, to check the breaking strength of the fastener/closing system and the stringing material (metal chain, leather or nylon cord), is a key way to ensure buyers and end-users are happy with its long-term performance.

Major producers of both luxury and costume fashion jewellery use Mecmesin tensile, compression and torque testers as part of their quality-control processes for checking the physical and mechanical strength of their products. A wide range of dedicated tension grips allied with easy-to-use testing software make the Mecmesin bench-top testers a popular choice for operators and QC Managers alike.