Watch: preforms off the line
What a preform mould has to get right
A PET bottle starts life as a preform — a thick-walled, test-tube-shaped part with a finished neck, later reheated and blown into the finished bottle on a PET stretch blow molding machine. The preform mould is where the important decisions are locked in: how many cavities run per shot, how the hot runner feeds them, the exact neck finish, the gate and the cooling. Get these right and every preform is identical and blows into a good bottle; get them wrong and you fight short shots, unbalanced walls and neck defects for the life of the tool.
Cavitation — matching output to the machine
Cavity count comes from your target output and the machine tonnage. A 16-cavity mould suits a starter line; 24, 32, 48 and 72 cavities scale up water and beverage output. More cavities need more clamping force and a perfectly balanced hot runner, because one cold or over-packed cavity spoils the whole shot.
Hot runner, gate and neck finish
Production preform moulds use a hot-runner system with valve gates: heated manifolds feed melt to every cavity, balancing fill, removing runner scrap and leaving a clean gate. The neck finish (thread and support ledge — PCO 1810, 1881, 28 mm and so on) is a precision insert that must match your cap and filling line exactly.
Cooling and cycle time
Preforms are thick, so cooling drives the cycle. Conformal cooling in the cavities and cores, plus post-mould cooling on the take-out robot, lets the next shot start sooner without deforming the parts.
FAQ
What is a PET preform mould?
A PET preform mould is the injection mould that shapes molten PET into preforms - the small test-tube-shaped parts with a finished neck and thread that are later reheated and stretch-blown into bottles. The mould defines the preform weight, wall thickness, neck finish and how many cavities run per shot.
How many cavities should a PET preform mould have?
From a single cavity up to 96 or more. Cavity count is chosen from your required output and the machine tonnage: more cavities mean more preforms per shot but need a bigger machine and a balanced hot runner so every cavity fills equally. Common commercial moulds run 16, 24, 32, 48 or 72 cavities.
What is the neck finish and why does it matter?
The neck finish is the standardised thread and support ledge at the top of the preform (for example PCO 1810, 1881, 28 mm, 30/25). It has to match the cap and the filling line exactly, so the neck insert is a precision part of the mould. AMAN cuts the neck to the standard your cap and line use.
Hot runner or cold runner for preform moulds?
High-cavity PET preform moulds use a hot-runner system: heated manifolds and nozzles feed every cavity through valve gates, which balances fill, removes runner scrap and gives a clean gate mark. It is the standard for production preform tooling.
What drives preform mould cooling and cycle time?
Preforms are thick-walled, so cooling dominates the cycle. Good moulds use cooling channels in the cavities, cores and neck inserts, plus post-mould cooling on the take-out plate, so the next shot can start sooner without the preforms deforming.
Does AMAN supply the preform mould and the machine together?
Yes. AMAN builds the PET preform injection moulds in-house and supplies the matching preform injection machine, so cavity count, tonnage, hot runner and neck finish are engineered together for your bottle programme.
Speccing a PET preform mould or machine?
Tell us your bottle, neck finish and output — AMAN builds the preform mould in-house and supplies the matching machine. Send your drawing and get an exact quote within 24–48 hours.
PET preform moulds → PET preform machines →Send us your bottle or cap drawing
One upload is enough to start. You can attach the drawing straight to the enquiry form, with no email back and forth first.
- ✓A drawing, a 3D file, or clear photos of every side of the sample
- ✓Length, width, height and weight of the finished part
- ✓Material, and the neck finish if it is a bottle, jar or closure
- ✓How many cavities, or the machine tonnage, or the parts per hour you need