A 160 ton two platen machine suits deep and medium-sized PP and PE parts: buckets and round tubs, storage boxes and containers with lids, baskets and open trays, small dustbins and tall household containers. With a 10% reserve (a starting margin, not a rule), it carries about 345 to 518 cm² of projected area at PP tonnage factors of 3 to 2 US t/in².
That is one round rim of about 210 to 257 mm, or several smaller cavities. The two-platen clamp earns its place on parts that are deep rather than wide, because the long opening stroke lets a tall part clear the core. Clamp sets the width of what you can mould; stroke and mould height set the depth.
Key Takeaways
- With a 10% reserve, 160 t carries about 345 to 518 cm² of PP area, one round rim of roughly 210 to 257 mm.
- Projected area is the outline seen from the parting line, so a deep bucket and a shallow tray with the same rim need the same clamp.
- Through openings in baskets and trays are deducted from the area, which can let a larger footprint fit.
- Food storage boxes must use plastics that meet the Indian Standards listed under the FSSAI Packaging Regulations, such as IS 10910 for PP.
What Can a 160 Ton Two Platen Machine Make?
Buckets, round tubs, storage boxes, food containers with lids, laundry and vegetable baskets, open trays, small dustbins and other tall household parts. The table shows how much projected area each group can use across all cavities at 160 t, once a 10% reserve is held back.
Largest total projected area on a 160 ton two platen machine, with a 10% reserve (sizes are assumed examples)
| Product group | Tonnage factor (US t/in²) | Largest total area at 160 t | What that can mean |
|---|---|---|---|
| Buckets and round tubs (PP) | 2 to 3 | 345 to 518 cm² | One rim of about 210 mm at factor 3, up to about 257 mm at factor 2 |
| Storage boxes and containers (PP) | 2 to 3 | 345 to 518 cm² | One 250 × 180 mm box (450 cm²) needs about 139 t to 209 t, so it fits only toward factor 2 |
| Baskets and open trays (PP) | 2 to 3 | 345 to 518 cm² net | A larger footprint can fit once slots and holes are deducted |
| Small dustbins and tall containers (PP or PE) | 2 to 3 | 345 to 518 cm² | Clamp as for a bucket of the same rim; stroke and mould height decide |
Polyethylene sits at the low end of the factor range, so PE tubs and containers can use the larger figure more often than PP parts with long flow paths. Lids need the same clamp as the containers they close, because the rim outline is the same, but far less opening.
How Do You Work Out the Clamp for Your Part?
Take the projected area of one part from the parting line, subtract through openings, multiply by the cavity count and add any cold-runner area. Multiply by a tonnage factor for the resin and wall, convert to metric tonnes, add a reserve and compare the total with 160 t.
This is the method John Williams of RJG sets out in Plastics Technology. He gives a typical range of 2 to 10 US t/in² and suggests 3 as a starting point where no better data exists. Flow length, wall thickness, gate size, gate location and the number of gates all move the factor.
SPE Plastics Engineering's guide by A. Urbina puts PP at 2 to 3 US t/in², with polyethylene at the low end and polycarbonate toward the high end. One US t/in² equals 0.1406 t/cm², so factors of 2 and 3 become 0.281 and 0.422 t/cm². At 160 t, 145.5 t usable divided by those factors gives 518 and 345 cm².
Spare clamp is not a reason to use it. Williams describes a mould that needed about 100 tons but was clamped at a 400-ton machine's maximum; the cavity block split in two places. Set the clamp from the calculation plus a modest reserve.
Why Choose a Two-Platen Clamp at 160 t?
Because the part is deep, not because the clamp is stronger. A two-platen machine locks the moving platen on the tie bars and builds tonnage with short-stroke cylinders, so it is shorter overall and can offer a long opening. That suits buckets, dustbins and tall containers.
Mikell Knights' Plastics Technology article on hybrid clamps describes this hydromechanical style and notes that it reduces machine length compared with toggles or fully hydraulic machines. It also reports, as builders' claims, that direct hydraulic clamping gives finer pressure control and a greater mould-height range.
How the opening on a two-platen machine changes with mould height, and how that compares with a toggle, is covered in the opening stroke article in this series. Planning the mould itself for a deep part is covered in the mould height article.
Which Food-Contact Rules Apply to Storage Containers in India?
Food storage boxes and tubs in direct food contact fall under the FSSAI Packaging Regulations 2018. The plastic must conform to listed Indian Standards, such as IS 10910 for PP and IS 10146 for PE, and pass an overall migration limit of 60 mg/kg or 10 mg/dm².
Migration is tested to IS 9845, pigments must meet IS 9833, and food businesses need a certificate of conformity from an NABL-accredited lab for packaging in direct food contact. Buckets for water, paint or chemicals sit outside these rules, though packaging rules on recycled content can apply, as the bucket article in this series explains.
Our view: if a 160 t two-platen machine will run food boxes and utility buckets, keep separate resin, masterbatch and regrind for each. Mixing a utility regrind into a food box is a traceability problem that no clamp setting can fix.
What Should You Send Before Choosing a Machine?
Send the rim size, height, wall thickness, part weight, resin grade and target cavity count for each part, plus the closed mould thickness if the mould exists. Clamp, opening, mould height and shot can then be checked together. See the 160 ton two platen injection moulding machine page.
Frequently Asked Questions About Parts for a 160 t Two-Platen Machine
Can a 160 t two-platen machine make crates?
Small crates and baskets, yes, if the net projected area after deducting slots stays within about 345 to 518 cm² at PP factors of 3 to 2. Full-size industrial crates usually have a much larger footprint, which points to a higher tonnage. Check the tie-bar gap as well, because crate moulds are wide.
Does a deeper part need more clamp force?
No. Clamp follows the projected area, the outline seen from the parting line, not the depth. A deep bucket and a shallow tray with the same rim need the same clamp. Depth changes the opening stroke, the mould height, the shot weight and the cooling time instead.
Is a two-platen machine a good choice for small parts?
Usually not on its own. A small mould on a large platen can let the platens bend under clamp and flash in the middle, and the machine's long stroke and size bring little benefit. Keep small, shallow parts on a smaller machine where you can.
Should I use the rated 160 t on every mould?
No. Set the clamp from the projected area calculation plus a modest reserve. Over-clamping can crush vents, roll the parting line, crack mould blocks and stress the machine. A mould that needs 110 t should run near 110 to 120 t, not at the machine's maximum.
Can I run PE and PP parts on the same machine?
Yes, with a purge between them and attention to temperature settings. PE often needs a lower tonnage factor than PP for the same part, so recalculate the clamp when you switch. Keep regrind streams separate, because mixed PE and PP regrind can weaken parts.
Related Articles
- Buckets and Storage Boxes on a 160 Ton Two Platen Machine
- 160 Ton Two Platen vs Toggle Machine: Opening Stroke Compared
- Deep Moulds on a 1000 mm Stroke: Planning Mould Height
Sources & References
- Plastics Technology, J. Williams (RJG): Clamp Tonnage: More Is Better...Right?
- SPE Plastics Engineering, A. Urbina: Mastering Clamping Force Calculation
- Plastics Technology, M. Knights: Hybrid Injection Clamps: The Best of Both Worlds?
- Food Safety and Standards Authority of India (FSSAI): Food Safety and Standards (Packaging) Regulations, 2018, compendium
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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