Neck finishes, container standards, mould materials and drawings - the knowledge that makes a mould order fit every machine around it.
Every mould order has one line that matters more than the rest: the neck finish. It is the moulded top of the container - threads, sealing face, dimensions - and it silently locks together four machines that never speak to each other: the mould that forms it, the cap that matches it, the filler that grips it, and the wash line that handles it. Change the finish later and you are re-buying moulds, caps and tooling.
This guide explains neck finishes by container type, the mould materials that suit each process, and the drawings a moulder needs to build it right the first time. It completes the mould story started in our mould care guide - and its decisions feed straight into the machines on our blow and injection pages.
The FoundationThink of the neck finish as a contract between four parties. The mould promises the shape. The cap promises to seal it. The filler promises to handle it. The wash line promises to grip it. Break the contract anywhere - a thread standard that your cap supplier does not stock, a neck height your grippers miss - and the plant discovers it on day one of production, when it is most expensive.
PCO 1810 (older, taller), PCO 1881 (shorter, lighter caps) and 30/25 for hot-fill. The finish lives on the preform - buy preforms and caps that match your market's standards.
Screw necks (55-61mm) for tamper-evident caps, or snap-on crowns for speed on the wash line. Not interchangeable - and wash-line grippers follow the choice.
Open-head drums with locking ring lids, or narrow-mouth with buttress threads for chemicals. UN-rated drums lock the finish design to the certification.
Common standards in 18mm to 63mm by region and industry. Match to locally available caps and your filler's capping heads.
The global rule: standard finishes have cap ecosystems behind them. Custom finishes mean custom caps - a cost and supply-chain decision, not just a design one.
Light, fast-machining, excellent heat transfer for short cycles. The default for water-contact blow moulds, from 5L bottles to 20L jars.
Pre-hardened steel for mid-volume injection moulds - caps, crates, household parts. Balanced wear resistance and machinability.
Hardened steel for millions of cycles and abrasive or glass-filled materials. Costs more, lasts proportionally longer.
Channel layout, not just cavity shape, decides cycle time. Well-designed cooling channels are the difference between a 10-second and a 14-second cycle - forever.
A section drawing with the neck finish specified by standard and dimension, wall thicknesses and capacity at fill line. No drawing? Send a physical sample - we reverse-engineer it.
Mould mounting dimensions, platen daylight and clamp tonnage - so the mould fits your machine, not just your product.
What it will process and expected annual volume - they decide the steel grade and cooling design.
Trial shots with your material before the mould ships - the same philosophy as the 72-hour machine test, applied to the tool.
The finish should be decided before the body shape, because caps, fillers and wash lines all hang off it. Designing backwards re-buys everything.
A custom finish means custom caps forever - a supply-chain tax on every unit. Standard finishes carry ecosystems; use them.
Ordering production tooling without a trial run gambles the whole lead time on the first shot. Sampling costs days; re-cutting costs months.
Returnable jars meet grippers daily. A neck the grippers mishandle turns your hygiene process into your damage process - check the interface per the jar guide.
The neck finish is the moulded top of a container - the threads, sealing surface and dimensions that the cap matches. It is formed by the mould (blow) or the preform (PET) and it locks the container to a cap, a filling machine and a wash line.
28mm threads dominate water and CSD - PCO 1810 (older), PCO 1881 (shorter, lighter caps) and 30/25 for hot-fill. The finish is decided by the preform, so choose preforms and caps from your local supply before choosing moulds.
Two families dominate: screw necks (around 55-61mm) and snap-on crowns. They are not interchangeable - the jar, cap, wash-line grippers and filler must all match the same standard, so decide before ordering moulds.
Blow moulds: aluminium - lighter, faster to cool, machined quickly, ideal for water-contact containers. Injection moulds: steel (P20, H13 by volume) - wear resistance matters at millions of cycles. The material follows the process.
At minimum: a section drawing of the container with the neck finish specified by standard and dimension, wall thicknesses, capacity at fill line, and the machine's mounting interface. Send a physical sample and we reverse-engineer the rest.
Send the sample or the drawing - get the neck finish specified, the mould quoted and the sampling plan within 24 hours.