Two cords with the same nominal diameter can behave differently in the same stopper because their braid structure and density differ. Real-use testing is therefore as important as dimensions.
Measure the actual outer diameter Soft braided cords can compress under pressure, while firmer constructions compress less. Measure at several points and consider normal manufacturing tolerances.
Evaluate holding force for the application A hood, waist adjuster, bag opening and decorative cord do not require the same holding force. The spring or clamping force should allow comfortable adjustment while keeping the selected position securely.
Check friction and surface damage An overly narrow passage or sharp contact surface can cause fuzzing and abrasion on the cord jacket. Test repeated opening and closing, not just a few cycles.
Retest after washing Shrinkage, swelling or a change in surface character can alter the feel of the cord. For washable products, approve the cord-and-stopper system only after testing under the finished product's intended care conditions.
Use a reference sample in mass production Record the approved cord and stopper combination, including lot, color and dimensions. This makes repeat-order consistency easier to maintain.
Note: Technical content is provided for general information. Current testing and compliance requirements should be verified separately according to the final application, target market and customer standard.