A four-cavity mould making 18 g preforms on an 18 s cycle uses about 14.4 kg of PET an hour. At a drying time of about 4 hours, the dryer must hold about 58 kg of resin in process. When starting PET preform production, numbers like these size the dryer, the chiller and your resin stock before the machine itself.
This article covers the equipment a preform cell needs around the machine, how to size the dryer, what to measure from the first day, and the recycled-content rules to plan for.
Key Takeaways
- PET must be dried below 50 ppm of water before moulding, with drying air at a dew point of minus 40 °C or lower.
- Drying takes about 4 h at 175 °C or up to 6 h at 160 °C, so the hopper size follows from resin use per hour.
- Drying can use up to 15% of process energy, so size the dryer to the jobs you will run, not the largest you might.
- The PWM Rules set recycled-content targets for rigid plastic packaging of at least 30% in 2025-26, rising to 60% by 2028-29.
What Equipment Does Starting PET Preform Production Need?
A dehumidifying dryer, a chiller, the preform mould with its hot-runner controller, the machine, and a way to test preforms. You also need access to blow moulding, in house or through a partner, to turn samples into bottles. The dryer matters most, because wet PET cannot make good preforms.
Equipment for starting PET preform production
| Item | Why it is needed | First number to check |
|---|---|---|
| Dehumidifying dryer | Removes moisture that would cut IV in the barrel | Below 50 ppm water; dew point minus 40 °C or lower |
| Crystalliser (for amorphous feed only) | Stops amorphous regrind or flake sticking in the dryer | Needed only if you feed amorphous material |
| Chiller | Cools the mould fast enough to keep preforms clear | Flow and temperature to the mould maker's figures |
| Hot-runner controller | Holds each nozzle and the manifold at temperature | Zones to match the mould |
| IV and acetaldehyde testing | Shows degradation the eye cannot see | In house or through an outside lab |
| Blow moulding access | Proves the preforms make good bottles | Sample bottles for the buyer's tests |
Our view: commission the dryer and check its dew point before the first mould trial, not after the first bad batch. A machine can be set up quickly, but a hopper of wet PET can spoil every shot until the cause is found.
How Do You Size the Dryer for a 75 t Preform Machine?
From throughput and drying time. Multiply resin use per hour by the drying time to get the resin the hopper must hold in process. The PETplanet Rapid Guide gives about 4 hours at 175 °C, or up to 6 hours at 160 °C, for drying PET.
Airflow matters as much as heat. In an extract from his book Bottles, Preforms and Closures, published in PETplanet Insider, Ottmar Brandau gives the required airflow as about 4 m³/h for each kg/h of resin. He also puts 50 ppm as the most water the resin can carry at the feed throat, giving an acceptable IV drop of 0.03 to 0.04.
Brandau suggests finding the real residence time by practical experiment, with a handful of colour pellets placed on top of the resin in the hopper. A hopper that is too small, or kept half full, dries for less time than its rating suggests.
Drying also costs money. The energy saving guide for injection moulders from ExxonMobil, AMI and Tangram Technology says drying can use up to 15% of process energy, so a dryer sized for a job you may never run wastes power on the jobs you do run.
What Should You Measure From the First Day?
Dew point, drying temperature, preform weight per cavity, and IV loss against the resin lot. These four tell you whether the material is dry, whether the process is stable and whether the preforms will blow well. Record them every shift from the start of production.
Dew point is the first alarm to watch. The PETplanet Rapid Guide says a dew point above minus 40 °C must be rectified, because the resin will not dry below 50 ppm, however long it sits in the hopper.
Weight per cavity is the cheapest early warning. A drifting weight can point to a blocked hot-runner tip, a heater fault or a change in the resin, long before a customer sees a problem.
IV loss needs a lab, in house or outside. How much loss is acceptable, and how to check it on trial preforms, is set out in the trial moulds article in this series.
Which Recycled-Content Rules Should You Plan For?
The Plastic Waste Management (Amendment) Rules notified on 31 March 2026 set recycled-content targets for rigid plastic packaging: at least 30% in 2025-26, rising to 60% by 2028-29. Exemptions apply where FSSAI and similar rules restrict recycled content, so food preforms depend on FSSAI's position.
For non-food bottles such as detergent, agrochemical or some cosmetic packs, rPET can enter your planning sooner. It brings its own handling: flake or pellet may arrive amorphous, need crystallising before drying, and vary in IV from lot to lot, so test each lot.
According to Polymerupdate's report on the amendment, shortfalls for 2025-26 can be carried forward for up to three years, and penalties range from ₹10,000 to ₹15,00,000. Ask your brand-owner customers which targets they must meet, because their targets set the recycled content they will ask you to use.
What Should You Send Before Starting PET Preform Production?
Send the preform weights, neck finishes, target monthly quantities, resin grades including any rPET, and whether the bottles will hold food or drink. With those, machine, dryer, chiller and mould can be sized as one cell. See the 75 ton PET injection moulding machine page.
Frequently Asked Questions About Starting Preform Production
Can I start preform production with one machine and one mould?
Yes, and it keeps risk low while you learn drying, changeovers and quality checks. The weak point is downtime: one dryer, chiller or hot-runner fault stops all output. Keep spare heaters, thermocouples and a hot-runner nozzle tip on site, and agree a service plan before you start.
Do I need a crystalliser as well as a dryer?
Only if you feed amorphous material, such as some regrind or recycled flake. Virgin bottle-grade chips are supplied crystallised. Amorphous material can soften and stick together at drying temperatures, blocking the hopper, so it needs crystallising first. Ask your rPET supplier whether its pellets arrive crystallised.
Can I reuse PET preform regrind?
It can be done with care. Regrind has already lost some IV, can be amorphous and dusty, and must be dried like fresh resin. Keep the share low and constant, test IV on preforms made with it, and check whether the bottle buyer or food rules allow it at all.
How should I size the chiller for a preform machine?
Size it from the heat removed per hour, not from the clamp rating. Ask the mould maker for flow and temperature at the mould, and add machine oil cooling if it uses chilled water. The ExxonMobil, AMI and Tangram guide notes each 1 °C warmer chilled water cuts chiller cost by about 3%.
Should I buy PET resin in bags or in bulk at the start?
Bags suit the first months, while volumes and grades settle. Keep bags sealed until use, because PET picks up moisture from the air, and store them off the floor. Move to bulk once consumption is steady and your storage and hopper loader can keep material dry.
Related Articles
- What PET Products Can You Make on a 75 Ton Machine?
- Small Pharma and Cosmetic Bottle Preforms on a 75 Ton Machine
- Running Trial Preform Moulds Before Scaling Up Production
Sources & References
- PETplanet Insider, R. Unterlander and O. Brandau: The Rapid Guide to Perfect Preforms (Vol. 11, No. 11/10, p. 24)
- PETplanet Insider, O. Brandau: Drying of PET: Bottles, Preforms and Closures, part 13 (Vol. 15, No. 08/14, p. 28)
- ExxonMobil, AMI and Tangram Technology: An Energy Saving Guide for Injection Moulders
- Polymerupdate, D. K. Jha: India eases plastic recycling regulations
Technical Disclaimer
Disclaimer: The information provided in this document is for general informational and educational purposes only. It is based on technical references and industry information available at the time of preparation and may be subject to change. It does not constitute engineering, technical, commercial or professional advice, nor does it constitute a quotation, specification, warranty or contractual commitment by Pratishna Engineers.
Actual injection moulding machine and process requirements vary according to the component design, material, mould, production volume, machine configuration and operating conditions. The information, examples, calculations and recommendations provided should be independently evaluated and verified for the specific application before making any equipment, process or production decision. Information obtained from third-party sources remains subject to the accuracy and limitations of those sources.
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