A 150 ton machine set up for PET can mould multi-cavity preforms for water, soft drink, edible oil, household and pharmaceutical bottles, wide-mouth jar preforms for food and dry goods, and thick-wall PETG jars for cosmetics. Which PET products on a 150 ton machine you can run, and in how many cavities, comes down to three limits: the total neck area the clamp can hold shut, the good shot window of the barrel, and the injection rate the mould needs. On light preforms the barrel can run out well before the clamp does, as the worked example shows.
Key Takeaways
- With a 10% reserve, a 150 t clamp holds roughly 194 to 334 cm² of total ledge area, depending on the pressure basis you use.
- Shot weight often caps the cavity count first, so check cavities × preform weight against the barrel's good PET shot window.
- Plan an injection rate of about 10 to 12 g/s per cavity for preforms.
- Water and food containers must use food-contact PET meeting IS 12252 under the FSSAI packaging regulations.
Which PET products on a 150 ton machine make sense?
Medium preforms in moderate cavity counts suit this size best: water, soft drink, edible oil, household chemical and pharmaceutical bottle preforms, plus wide-mouth jar preforms in a few cavities. Heavy, thick-wall PETG cosmetic jars also fit, where cooling time rather than clamp or shot sets the output.
The table gives a first sort by product. Resin grade follows the end use, and Reliance's Relpet listing gives a useful map: G5761 for still water, G5841 for aerated drinks and agrochemicals, G5801 for foods, water and FMCG containers such as cosmetics, hair oil and disinfectants, and H7761 for hot-fill juices and isotonic drinks.
PET products and what tends to limit them on a 150 t machine
| Product | Example ledge (assumed) | Main limit | Grade type |
|---|---|---|---|
| Still water bottle preform | 30 mm | Shot weight and injection rate | Still water grade |
| Soft drink preform | 33 mm | Shot weight; neck finish standard | Aerated drinks grade |
| Edible oil or household preform | 38 mm | Shot weight, then clamp | General purpose grade |
| Wide-mouth jar preform | 63 to 80 mm | Clamp area per cavity | Food grade |
| Thick-wall PETG cosmetic jar | Not a preform | Cooling time | PETG copolyester |
How many preform cavities can a 150 t clamp hold shut?
Divide the usable clamp force by a pressure factor to get the largest total ledge area, then divide by the area of one ledge. With a 10% reserve, 150 t allows about 334 cm² on a 400 bar guide and about 194 cm² on a cautious 5 US t/in² basis.
The 10% reserve is a starting margin, not a rule. The 400 bar figure is the guide cavity pressure SPE Plastics Engineering suggests when no better data exists; it converts to 0.408 t/cm². The 5 US t/in² basis, 0.703 t/cm², is a deliberately cautious assumption for thin preform walls. On that range, a 33 mm ledge allows 22 to 39 cavities by clamp, a 38 mm ledge 17 to 29, and a 48 mm ledge 10 to 18.
Use the clamp force printed on the spec sheet, not the size in the machine's name. The two can differ, and the sums should be rerun at the rated figure. Tie-bar spacing and cavity pitch then set a physical limit on top of the clamp limit. A wide ledge also loads the clamp far faster than a narrow one, which is why jar preforms run in so few cavities by comparison.
Why does shot weight often limit cavities before clamp force?
Clamp force grows with ledge area, but shot weight grows with every gram of every preform. On a 150 t machine with a modest barrel, a mould of light preforms can need far more melt than the barrel can deliver, while the clamp still has room to spare.
Machine shot ratings are given in grams of PS. PET melt is denser, about 1.15 g/cm³ against 0.945 for PS, so a barrel rated R g of PS holds about 1.22 × R g of PET melt at full stroke. Keeping the shot between 20% and 65% of barrel capacity, with 10% extra for check-valve leakage, the good PET shot runs from about 0.221 × R to 0.719 × R.
Injection rate is the third check. Preform guidance from PETplanet Insider puts it at about 10 to 12 g/s per cavity, so more cavities need a faster injection unit as well as a bigger barrel. Which screw size to pick within one machine is covered in the PET screw options article in this series.
A blunt view: buy a 150 t PET machine for its barrel and injection rate, not for its clamp. On preform work the clamp is rarely the limit you hit first.
What rules apply to PET water and food containers in India?
Under the FSSAI Packaging Regulations, 2018, PET for food containers must meet IS 12252, with an overall migration limit of 60 mg/kg. Packaged drinking water bottles need at least 85% transparency, and food businesses need an NABL lab certificate for packaging in direct food contact.
For a preform moulder this means the resin grade and its paperwork matter as much as the machine. Ask the resin supplier for the grade's food-contact statement, keep lot records, and make sure your customer's migration test covers the grade and colourant you actually run.
What should you send to size a 150 t machine for PET?
Send the preform or jar drawing with weight and ledge or neck diameter, the number of cavities you want, the target cycle, and the hot runner and post-mould cooling you plan to use. With those, a supplier can check clamp area, shot window and injection rate together. Compare your figures with the 150 ton PET injection moulding machine page.
Frequently Asked Questions About PET Products on a 150 Ton Machine
Can a 150 ton PET machine make bottles directly?
No. The injection machine makes preforms, which are reheated and stretch blow moulded into bottles on a separate blow moulding machine. Jars can be moulded either way: as wide-mouth preforms for blowing, or as finished thick-wall jars moulded directly, as covered in the PETG cosmetic jar article in this series.
Do I need a dryer to mould PET preforms?
Yes. PET must be dried below 50 ppm water before moulding, or it loses IV through hydrolysis. Preform guidance gives about 4 h at 175 °C, or up to 6 h at 160 °C, with dryer dew point at -40 °C or better. Size the dryer hopper for your kg/h, not the machine tonnage.
How many preforms per hour can a 150 ton machine make?
Output per hour equals 3,600 divided by cycle seconds, times cavities, times the good-shot share. Seven cavities on a 14 s cycle at 98% good shots gives about 1,764 preforms an hour. Cycle time follows wall thickness more than weight, so treat any figure as conditional on the preform design.
What is IV loss and why does it matter?
IV, or intrinsic viscosity, tracks the PET chain length. A drop of more than 0.04 dl/g between resin and preform is treated as a fault and weakens the bottle. You cannot see it in the preform, so test with an IV tester or melt viscometer. The usual causes are wet resin or severe thermal degradation.
Can the same machine run PET and other plastics?
It can, but PET work needs a dryer, a screw and barrel suited to PET, and careful purging between materials. Changeovers take time and risk contamination that shows as haze or black specks. A machine running mostly PET is easier to keep clean and consistent than one switching resins every week.
Related Articles
- Three Screw Options for PET on a 150 Ton Machine: Which One Fits Your Preform?
- Wide-Mouth Jar Preforms on a 150 Ton Machine
- Thick-Wall PETG Cosmetic Jars: Cooling Time and Sink Control
Sources & References
- SPE Plastics Engineering, A. Urbina: Mastering Clamping Force Calculation (Mar 2024)
- PETplanet Insider, R. Unterlander and O. Brandau: The Rapid Guide to Perfect Preforms, part 34: Wavy Body (Vol. 13, 11/2012)
- FSSAI: Food Safety and Standards (Packaging) Regulations, 2018, compendium
- UL Prospector: Polyester: Relpet grade listing
Technical Disclaimer
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