Define the product that will touch the bottle
Tell the supplier whether the bottle will hold water, a powdered product, a cosmetic, a food sample, a concentrated liquid, or another formulation. Record fill temperature, storage temperature, expected shelf life, cleaning process, pressure risk, and whether the bottle will be refilled. PET is used broadly, but suitability depends on the exact resin, additives, manufacturing process, and contact conditions. The buyer remains responsible for confirming current destination-market requirements with a qualified laboratory or compliance adviser.
The filled product also influences headspace, oxygen or moisture needs, color protection, and closure choice. A supplier cannot responsibly promise universal compatibility from a photograph. If chemical compatibility, hot filling, carbonation, sterilization, or long shelf life matters, arrange a documented test using the intended formula and final components. Keep retained samples from the approved trial so later production can be compared against a known reference.
Specify capacity, dimensions, weight, and neck finish
State whether 100ml is the nominal fill, brimful capacity, or a marketing size. Ask for a drawing showing overall height, body diameter, opening, thread, neck finish, label panel, overflow capacity, and dimensional tolerances. The target bottle weight affects feel, top-load performance, material use, and cost. Two bottles with the same capacity can behave very differently because their geometry and wall distribution are not the same.
Treat the neck and closure as a matched system. Identify the cap material, thread specification, liner or seal, tamper-evident feature, opening method, and application torque. If the cap comes from a separate source, send physical components for a compatibility trial. Approve the final assembled sample after transport simulation and storage, not only an empty bottle that was hand-tightened at the factory.
Control color, clarity, decoration, and label fit
Clear, translucent, opaque, and custom-color PET each create different approval questions. Define the color reference, acceptable variation, use of recycled content if requested, and whether visual defects will be judged empty or filled. For labels, provide the dieline, material, adhesive, print process, application direction, seam position, and barcode quiet zone. Curved shoulders and narrow label panels can limit the usable artwork area.
Screen printing, labels, sleeves, and other decoration methods need their own adhesion and appearance criteria. A digital proof confirms layout but cannot prove real color, scuff resistance, registration, or how the graphic looks on the filled container. Approve a decorated physical sample under representative lighting and handling. If the bottle is packed tightly, include abrasion protection or a partition design in the packaging review.
Build a quality plan around the filled system
A useful inspection plan covers identity, dimensions, capacity, weight, appearance, neck condition, closure fit, seal integrity, decoration, cleanliness, and packaging. Define the test method and acceptance rule before production. Leak testing should specify fill level, liquid, cap torque, orientation, duration, temperature, movement, and acceptable moisture. Top-load or drop checks should reflect the actual carton and distribution route rather than a generic demonstration.
Request traceability for resin, color masterbatch, closure components, production date, cavity, and lot where practical. Changes to material source, preform, mold, cap, liner, pigment, label adhesive, or packing can affect the approved configuration. A clear change-control rule is more valuable than a broad promise that all bottles are identical. Reports and declarations must be matched to the exact sample and component scope.
Quote the real commercial program
Ask suppliers to separate bottle, cap, decoration, label, unit packing, inner packing, export carton, tooling, sampling, testing, and freight-related costs. State the quantity by color and version, delivery destination, Incoterm, required arrival date, and forecast after the first order. This prevents a low base price from hiding a different closure, lighter bottle, bulk packing, or unsupported compliance assumption.
Plan approvals backward from the launch date. Allow time for drawing review, mold or sample confirmation, filled-product testing, artwork, decoration sample, packaging trial, production, inspection, and transport. For repeat programs, agree how forecasts, safety stock, color batches, spare caps, and obsolete artwork will be managed. The most reliable supplier is the one that controls the approved specification through every reorder.
