Plastic Packaging Manufacturing: From Resin Pellet to Export Carton
Eleven production stages run inside two plants in Guangdong — 10+ injection-molding machines, 30+ automatic blow-molding lines, 15,000 ㎡ of floor area and 200,000 pieces a day.
Every bottle we ship follows the same eleven stages, and all of them happen on our own floor
Raw material → preform or parison → injection → ISBM or EBM → trimming → inspection → decoration → closure matching → final QC → packing → export.
Nothing in that chain is subcontracted to a third-party molder. That is the whole point of running two plants, an in-house mold shop and a decoration department next to each other: when a print position drifts or a neck measures out of tolerance, the fix happens in the same building the same day rather than becoming a conversation between two suppliers.
This page explains how the packaging is made — the eleven stages, the machines and the process controls. For the commercial view — what we take on for you under one contract, from material selection to export paperwork — see one-stop packaging capability. For the inspection and documentation system behind each stage, see quality & compliance.
The eleven stages of a production run
Each stage below is a real handover point with its own record. The number identifies where in the run it sits, not how long it takes — a stage that takes minutes still gets its own check.
Resin grade and supplier batch logged at IQC; moisture checked before drying.
PET route: an injection-molded preform. PE / PP route: an extruded parison tube.
10+ injection-molding machines run preforms, caps, pumps, sprayers and closures.
Stretch blow for PET, extrusion blow for PE and HDPE, on 30+ automatic blow-molding lines.
Tail, flash and gate removal, then the first dimensional check on the finished body.
First-article sign-off, then in-process checks on weight, wall thickness and neck.
Silk screen, hot stamping, labelling and spray coating, run in the same building.
Your cap, pump, sprayer or dropper fitted, then torque and leak tested.
AQL 2.5, 1.2 m drop test, air-pressure leak test and a QC report per lot.
Carton count, labelling and shipping marks checked against the packing list.
Turnkey export paperwork and 23 years of shipping cosmetics, personal care and household packaging.
The five stages that decide whether a bottle is right or wrong — injection, ISBM, EBM, tooling and decoration — each have a dedicated page below, because each one carries a different set of buyer decisions and a different set of defects.
What actually runs on our floor
Five processes, each explained by what the process is, what packaging it produces, which quality issues a buyer should watch, and what information we need from you before it can start.
Injection Molding
10+ machines producing PET preforms, caps, lotion pumps, mist sprayers, droppers, trigger sprayers and foamers, with tight neck tolerances.
Read more →ISBM — Injection Stretch Blow
The route for PET: a preform is reheated, stretched axially and blown radially so the polymer orients biaxially. Clarity and strength per gram.
Read more →EBM — Extrusion Blow
The route for HDPE, PE and PP: a parison is extruded, the mold closes around it and air inflates it in one continuous step.
Read more →Tooling and Molds
Stock mold or custom mold, private tooling built and held in-house, the development sequence, sampling and what decides tooling lead time.
Read more →Decoration Line
Silk screen, hot stamping, labelling and spray coating run in the same building as molding, with print-adhesion testing before the run is released.
Read more →Which route your bottle takes is decided by its material
There is no single line that makes every bottle. PET and the polyolefins run on different routes, with different tooling, different machine families and different mold numbering — PET tools are numbered SJT, PE tools SJE.
| Route | Material | Sequence | What it is good at |
|---|---|---|---|
| SJT — injection stretch blow | PET, PCR PET (rPET) | Resin sourcing → injection preform → stretch blow → silk screen or label → QC → warehouse → ship | Clarity, gloss, precise injection-molded necks and a high strength-to-weight ratio. The default for cosmetic, serum and spray bottles. |
| SJE — extrusion blow (one-step) | HDPE, PE, PP | Resin sourcing → extrusion blow (one step) → silk screen → QC → warehouse → ship | Opaque and coloured bodies, handles, non-round profiles and high-volume household shapes at a low piece cost. |
| Injection (both routes) | PET, HDPE, PE, PP, PETG | Resin sourcing → drying → injection → ejection → inspection → matching or blow | Preforms for the PET route, and every closure and dispenser: caps, pumps, sprayers, droppers, triggers and foamers. |
Resin preparation is shared by both routes and is the least visible part of the process. PET and PE resin dried at 170–180 °C for 3–4 h; masterbatch at 100–120 °C for 2 h. Moisture left in PET hydrolyses the polymer during processing, and a hydrolysed preform shows up as haze or brittleness that no amount of blow-tuning can recover.
The equipment and the buildings behind the numbers
Capacity claims are only useful if you can name the machines and the buildings they sit in. Here are ours, and what each one is for.
Manufacturing footprint
Equipment counts are current at the time of writing. If your project depends on a specific machine group or a reserved slot, say so at quotation stage and we will confirm availability in writing rather than assume it.
Where quality control actually happens in the flow
Three inspection gates sit inside the eleven stages. They are not a final checkpoint bolted onto the end — the earlier a defect is caught, the cheaper it is to fix.
| Gate | Stages covered | What is checked | What it prevents |
|---|---|---|---|
| IQC — incoming material | Stage 01, before anything is melted | Resin grade and supplier batch number logged, moisture content checked before drying, masterbatch colour matched against the approved chip, recycled content confirmed against supply-chain records | Bad or substituted resin reaching a machine, and colour that cannot be corrected downstream |
| IPQC — in process | Stages 03 to 07, on the line | First-article sign-off before mass production, weight within ±2%, wall thickness at four points per cavity, visual defect inspection every 30 minutes, neck finish and thread fit against your closure | A drifting parameter running for a full shift before anyone notices |
| OQC — pre-shipment | Stages 08 to 10, on the finished lot | AQL 2.5 sampling, air-pressure leak testing on the assembled bottle and closure, 1.2 m drop test where the route justifies it, carton count and shipping marks, QC report issued per lot | A sealed carton arriving with a leak, a wrong count or the wrong shipping mark |
The full inspection plan, the testing methods and the documentation that comes with each lot are on the quality & compliance page, including the strict difference between a certification, a test report, a material document, a recycled-content record and a compliance statement.
Start from the material, then the engineering, then the product
Manufacturing is the third step of four. If you have arrived here first, the useful order is: pick the material, check the engineering constraint, then look at a real product.
Material
What the fill chemistry and the storage conditions rule in or out. Start at the materials hub, or compare all six side by side.
Read the guide →Engineering
Geometry, neck and closure, decoration, colour and the tests that prove the pack holds.
Read the guide →Manufacturing
How the chosen material and geometry actually get made, on which route, with which controls. This page.
Product
A real part from the library, with its material, capacity, neck finish and mold number stated.
Read the guide →Manufacturing questions, answered
How many production stages does one of your bottles go through?+
Eleven: raw material, preform or parison, injection, ISBM or EBM, trimming, inspection, decoration, closure matching, final QC, packing and export. Each stage is a handover point with its own record, so a problem can be traced back to the stage that produced it.
Which processes do you run in-house?+
Injection molding, injection stretch blow (ISBM), extrusion blow (EBM), trimming, decoration (silk screen, hot stamping, labelling, pad printing, shrink sleeve and spray coating), closure matching, final QC, packing and export paperwork. Tooling is designed, cut and maintained in our own mold shop.
Where are your factories?+
Two plants in Guangdong, China — Shenzhen Pingshan and Huizhou Huiyang — plus a Guangzhou office. Injection, stretch blow, extrusion blow, decoration and QC all run inside those two sites.
How much can you produce?+
200,000 pieces per day across both plants, from 10+ injection-molding machines and 30+ automatic blow-molding lines on 15,000 ㎡ of manufacturing floor. Volume for a specific project is quoted against its product, mold and material rather than from the factory-wide figure.
Do you subcontract any molding?+
No. Molding, decoration, assembly and quality control all happen under our own roofs. That is deliberate: it keeps one accountable owner when something needs to change, instead of an argument between suppliers.
How do I know which route my bottle will take?+
The material decides it. PET and PCR PET go the injection stretch blow route (SJT mold numbering); HDPE, PE and PP go the extrusion blow route (SJE numbering). Closures and dispensers are injection molded either way. See the material comparison if you have not settled the material yet.
Can I visit the factory or send an inspector?+
Yes. Tell us the date and we will make the line, the QC records and the warehouse available. Third-party factory audits are a normal part of onboarding for overseas brands, and audit records are available on request — see quality & compliance.
Manufacturing, quality and materials
Have a bottle in mind? Let’s work out how it gets made.
Send us the material, the capacity and the closure you have in mind. We will come back with the route, the tooling position and the sampling window.
Keep reading
Material, engineering and buying pages that this one sits next to.
Products behind this page
Real items from the Shijin stock-mold library. Shown specifications are the published ones; a quotation is built from your own drawing and fill volume.
1000ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →500ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →750ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →320ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →250ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →1000ml PET Bottle
Published specification, stock mold, MOQ 5,000 pcs.
View product →Projects this topic appears in
Programmes we ran with brand and importer teams, with material, sampling and volume recorded.
USA Skincare Brand: 15-50 ml PETG Serum Dropper | Shijin
PETG serum dropper, 15-50 ml, United States
Read the project record →Germany Personal Care: HDPE Body Wash, Four Reorders | Shijin
HDPE body wash, four closure options, Germany
Read the project record →Netherlands Cleaning: PCR PET Trigger Spray at 30% Recycled | Shijin
PCR PET trigger spray, Netherlands
Read the project record →