Five checks before approving a PET preform
Neck finish, IV, color, acetaldehyde and blowing performance should be reviewed as one production system.
A preform is a component of a bottle system. It should not be approved on weight or neck diameter alone: the closure, blowing machine, filling conditions and final package all have to work together. The following five checks turn a sample request into a usable technical approval.
1. Define the finished bottle and neck finish
Share the intended volume, bottle drawing, product, closure and filling line. Confirm the neck standard and dimensional tolerances against the actual cap. A nominal diameter is not enough to establish thread fit, sealing or opening force.
2. Confirm resin and application requirements
Ask for the material grade and batch documentation. Intrinsic viscosity, colour and any acetaldehyde target should be considered against the beverage or other end use, storage conditions and destination-market requirements. Do not infer food-contact approval from a generic PET description; request the relevant declaration for the specific material and market.
3. Evaluate the blowing window
Run representative samples on the intended machine. Record heating profile, cavity behaviour, cycle speed, wall distribution, base formation and scrap. A preform that looks correct in the carton may still create thin spots or uneven bottle strength in the line.
4. Test the bottle and closure together
Check fill volume, top load, leak performance, cap torque and transport behaviour using the final bottle. Carbonated and still products impose different demands, and large bottles may require a handle tested with the cap and neck as a system.
5. Approve the commercial handover
Agree on the approved sample, drawing revision, acceptance ranges, traceability, packaging, monthly volume and documents supplied with each lot. Compare the first commercial batch with the trial results before relying on long-term supply.
Tell Nexis the destination country, neck finish, target bottle and filling process. We can use those details to shortlist a relevant preform family and arrange a technically meaningful quotation.