Plastic Cap Moulds · 10 min read

Published: September 29, 2026

Bottle Cap Mold Cavity Selection Guide: 8 to 96 Cavities

Choose a cap mould cavity count from saleable output, machine compatibility, maintenance capacity and total-cell investment.

Bottle cap mould cavity selection is a capacity, machine and risk decision. A 96-cavity mould is not automatically more economical than a 24- or 48-cavity mould if the injection machine, hot runner, cooling system, maintenance resources or demand profile cannot support it.

This guide compares common 8, 16, 24, 32, 48, 64, 72 and 96 cavity options. It does not prescribe universal cycle times or output figures; those must be confirmed for the actual cap, resin, mould and production cell.

Calculate annual demand from saleable caps, planned operating hours, anticipated scrap, planned maintenance and line availability. Then compare feasible cavity counts against the injection machine’s shot capacity, clamp force, platen dimensions, nozzle arrangement and utilities.

The relevant output equation is simple: saleable parts per hour depend on cavity count, sustained cycle time and yield. The difficult part is proving that all three remain stable after installation. Ask suppliers to state their assumptions instead of comparing an optimistic cycle figure from one short factory trial.

This is a decision framework, not a machine-sizing chart. Actual clamp force, injection volume, plastification, nozzle pitch and cooling load are cap-specific.

Cycle time is affected by cap wall thickness, resin, gate design, cooling, ejection, automation, mould temperature, line discipline and cavity balance. High cavitation can spread fixed time across more parts, but it also makes balance and maintenance more consequential.

Ask for the trial conditions behind any quoted cycle time: resin type, machine model, hot-runner setup, mould temperature, sample count and evidence that samples were taken across the cavity layout. If a result cannot be explained, it cannot be used confidently in a financial model.

Before choosing 48 cavities or above, confirm more than clamp tonnage. The machine should accommodate the mould envelope, platen pattern, injection unit, hot-runner electrical load, cooling connections, ejection requirement and automation space. A cap mould may also need coordination with a cap slitter, vision inspection, conveyor, liner application or packing system.

Installation preparation should document voltage, controller interfaces, water quality and flow, air supply where used, lifting points, safety requirements and start-up responsibilities. These details reduce avoidable delays after shipment.

Higher cavity count raises potential output but also increases the number of cavity, core, gate and cooling components that need traceable maintenance. A buyer should ask for a cavity map, critical-spares list, wear-part references and instructions for isolating or servicing a component where the mould design permits.

For high-cavity programmes, review preventive maintenance before purchase. This includes cooling-circuit checks, gate inspection, heater and thermocouple records, guide and alignment condition, and a documented spare-parts package.

Investment cost includes more than the mould. A higher-cavity solution can require a larger injection machine, stronger cooling, more sophisticated hot runner and controller, handling equipment, inspection capacity, spares and technical support. The right decision compares lifecycle operating practicality with the demand profile rather than focusing only on initial mould price.

For each cavity proposal, define the acceptance evidence before manufacture. A meaningful factory test records mould operation, identified samples, cap weight and appearance, relevant functional checks and any open points. Shipment inspection should cover mould condition, spares, wiring and water labels, export preservation, documents and crate closure.