PET products on a 100 ton machine: what to check first for each (grades are examples from Reliance's Relpet bottle-grade listing)
| PET product | Example Indian grade | What to check first at 100 t |
|---|---|---|
| Still water bottle preforms | Relpet G5761, listed for still water | Shot weight per cavity and cycle time |
| Carbonated drink preforms | Relpet G5841 or QH5821, listed for aerated drinks | Neck finish and wall thickness |
| Hot-fill juice and isotonic drink preforms | Relpet H7761, listed for hot filling | Grade and neck design, agreed with the bottler |
| Edible oil, hair oil and disinfectant bottle preforms | Relpet G5801, listed for FMCG containers | Colour, neck size and cavity count |
| Pharma and small cosmetic bottle preforms | Relpet G5801, listed for pharmaceuticals | Small shots and time in the barrel |
| Wide-mouth jar preforms | Grade to suit the filled product | Clamp per cavity and mould width |
A 100 t clamp can hold multi-cavity moulds for narrow-neck preforms used in water, soft drink, edible oil, hair oil, disinfectant and pharma bottles, and a few cavities of wide-mouth jar preforms. For narrow necks the clamp leaves room to spare, as the worked example shows. Shot volume, cycle time and dry resin supply then decide how many cavities you can run.
Wide-mouth jars are different. Their larger diameter uses up the clamp after only a few cavities, so the jar mould is where a 100 t machine reaches its limit first.
Key Takeaways
- With a 10% reserve and an assumed PET factor of 5 US t/in², a 100 t clamp holds about 129 cm² of projected area.
- A narrow-neck preform with a 33 mm support ring projects about 8.6 cm², so the clamp alone would allow up to 15 cavities.
- A 70 mm wide-mouth jar preform projects about 38 cm², which stops a 100 t mould at three cavities.
- Food and drink PET in India falls under the FSSAI packaging rules, which list IS 12252 for PET.
How Do You Check Whether a PET Product Fits 100 t?
Take the area of each preform seen from the mould-opening direction, which is the circle at its widest diameter, multiply by the cavity count and a tonnage factor, and add a reserve. If the total stays under 100 t, the clamp can hold the mould shut.
Jeremy Williams of RJG sets out this method in Plastics Technology: projected area of one part, times cavities, plus any cold runner, times a tonnage factor. He suggests 3 US tons per square inch as a starting point when no better data exists. With a hot runner, only the cavities count, because melt in the manifold does not push on the parting line.
This article uses 5 US t/in² for PET preforms, an assumption taken from the top of the 3 to 5 range that Glenn Tremblay of Sabic gives for conventional moulding in PlasticsToday. It also holds back 10% of the clamp as a starting margin, not a rule. That leaves about 90.9 t, which at 0.703 t/cm² covers about 129 cm².
Trial data on your own mould replaces the assumed factor. A long, thin preform filled fast sits higher in the range than a short, thick one, and the limit then shrinks with it.
Which PET Products on a 100 Ton Machine Make Sense?
Narrow-neck preforms for water, soft drinks, edible oil, FMCG and pharma bottles fit with clamp to spare for many cavities. Wide-mouth jar preforms fit in small numbers. The cavity count you can run then comes from shot volume, cycle time and how much dry resin you can feed.
Reliance's Relpet listing on UL Prospector shows how grades follow the end use. G5761 is listed for still water; G5841 and the fast-reheat QH5821 for aerated drinks; H7761 for hot-fill juices, ice tea and isotonic drinks; and G5801 for foods, FMCG containers such as cosmetics, hair oil and disinfectants, and pharmaceuticals.
Agree the grade with your bottler before the mould is designed. A preform is only half the product: it is blown into a bottle later, so the bottle size, neck finish and blowing conditions all feed back into the preform you mould.
Our view: on a 100 t machine, start with narrow-neck preforms and treat wide-mouth jars as a second job, not the reason to buy. A jar mould capped at three cavities by clamp gives up the output a narrow-neck mould on the same machine can deliver.
What Limits a 100 t PET Machine Besides the Clamp?
Shot volume, mould width, cooling time and drying. The barrel must melt the whole shot inside its working range, the mould must fit between the tie bars, thick preform walls stretch the cycle, and the dryer must keep pace with the resin the machine uses each hour.
Mould width catches buyers out. A hot runner preform mould grows wider with every extra row of cavities, and the cavity area should sit fully inside the tie bars. Check the mould drawing against the tie-bar gap before agreeing the cavity count with your mould maker.
Each of the other limits has its own article in this series. Shot volume and barrel use are worked through in the 32 mm and 35 mm screw article, cycle time and output in the water bottle preform article, and dryer sizing in the PET moisture and drying article.
What Rules Apply to PET Packaging in India?
For food and drink, the FSSAI Packaging Regulations, 2018 require plastics in food containers to conform to listed Indian Standards, and they name IS 12252 for PET. Food businesses must also hold a certificate of conformity from an NABL lab for packaging in direct food contact.
In practice your customer builds that file, and you supply the resin documents behind it. Keep the data sheet and compliance letter for every grade you run, and record which lot went into which batch of preforms.
The same regulations allow recycled plastics in food contact only as FSSAI frames standards and guidelines for them. So recycled PET in a drinks preform is a question for your customer's compliance team before it is a question for your hopper. Non-food bottles, such as disinfectant or agro-chemical packs, are where recycled content can arrive first.
What Should You Send Before Choosing a 100 t PET Machine?
Send the preform drawing with weight, neck finish and support-ring diameter, the resin grade, the cavity count you want and your hourly output target. The clamp, shot and mould-width checks all follow from those. See the 100 ton PET injection moulding machine page.
Frequently Asked Questions About PET Products on a 100 Ton Machine
Is a 100 t clamp enough for a carbonated drink preform mould?
For the clamp, yes. A soft drink preform with a similar support ring projects about the same area as a water preform, so cavity limits from clamp are similar. The differences lie in the grade, the neck finish and the wall, which change the shot and the cooling time rather than the clamp.
Do preform moulds on a 100 t machine need a hot runner?
Not always, but it changes both checks. A hot runner keeps the runner out of the projected area and out of the shot, so only the cavities count. With a cold runner, add the runner's area to the clamp check and its weight to the shot, and plan what happens to the runner scrap.
What does 100 t offer over a 75 t machine for PET?
About 33% more clamp. At the same assumed factor and 10% reserve, 75 t covers about 97 cm² against 129 cm² at 100 t. For a 70 mm jar preform that is two cavities instead of three, while an eight-cavity narrow-neck mould, at about 53 t, sits inside both.
Can one 100 t machine run water and edible oil preforms?
Yes, with mould changes and a resin change between jobs. Plan the purge when switching grades or adding colour, and keep the dryer running at the right conditions for each grade. Group jobs by grade and colour where you can, so changeovers stay few and scrap stays low.
Does a heavier preform need more clamp?
Not directly. Clamp follows projected area, the circle at the preform's widest point, not its weight. A heavier preform with the same neck and ring needs about the same clamp but a larger shot and, where the wall is thicker, a longer cooling time, so check the barrel and the cycle before the clamp.
Related Articles
- Water Bottle Preforms on a 100 Ton Machine: What to Check First
- Choosing Between the 32 mm and 35 mm Screw for PET on a 100 Ton Machine
- PET Moisture and Drying: Why It Decides Preform Quality
Sources & References
- Plastics Technology, J. Williams (RJG): Clamp Tonnage: More Is Better...Right?
- PlasticsToday, G. Tremblay (Sabic Innovative Plastics): Never too thin
- UL Prospector: Polyester: Relpet grade listing (Reliance Industries)
- FSSAI: Food Safety and Standards (Packaging) Regulations, 2018, compendium
Technical Disclaimer
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