Pentagon Plastics explore the factors impacting on the cost of mould tooling
Investment in mould tooling can be significant, and each project involves several variables that will impact final mould tool costings. Pentagon Plastics is often asked for a ballpark estimate for manufacturing a new product that is still in the early design phase of a project, but this is not as straightforward a request as it may initially seem
The contributing factors in determining and quoting for bespoke tooling costs include:
Impressions
An increased number of impressions will reduce the piece price but will also increase the size and the complexity of the tool. Higher impressions also require more inserts, with their complex details and a larger bolster to house them in, further contributing to increased tool costs.
Hot Feed vs Cold Runner
A hot-fed tool is the ideal option for sustainability due to its ability to reduce piece price by improving cycle time, reducing waste material, and easing moulding processing. It can also increase the options for gating when designing the tool and minimise the need for sprue and runner-related components. It can simplify larger impression tooling, as long cold runners or three-plate cold runners are not required.
However, hot-fed tooling can be more expensive in its construction, requiring hot nozzle feeds, potentially multi-drop systems with manifold temperature control, and additional plates to support the system.
Cold runners are the best choice for low-impression tooling where a gate scar is acceptable. The tooling is cheaper to construct and can be delivered faster. The piece part cost will be higher, as the cold feed, which channels the material from the machine to the detail in the tool, must be accounted for in the component price.
Material choice of mould tools
The choice of tool material depends on:
- Material of the moulded product
- Complexity of the tool
- Life expectancy of the tool
Development tooling or ‘throw away’ tooling can be made from cheaper alloys such as Aluminium or P20 pre-toughened tool steel, and basic tooling and moulding die sets can be made from an unalloyed tool steel with excellent machinability, such as 1.1730. For commodity moulding materials where medium to high volume is needed, a chromium hot-work tool steel, such as 1.2344, that can be hardened, is a viable choice.
Moulding advanced engineering plastics or any with abrasive fillers, such as glass, requires a much harder-wearing tool steel, such as 1.2363 (A2), 1.2379 (D2), and CPM 10V. If lenses or other high-gloss finishes are desired on the part, corrosion-resistant tool steel is required, such as 1.2083, which can be highly polished post-matching.
The better the grade of tool steel, the more expensive the mould tool will be.
Complexity
The greater the complexity, the higher the associated manufacturing costs, including labour hours, machine time, and bought-in elements such as materials and bespoke services.
The simplest tool is often described as a 'straight open and close'; this means that to operate and release the component, the tool only needs to open in one plane. More complex component designs could require additional features and movements in opposing planes.
Levels of complexity can also limit the number of viable impressions in the tool or increase manufacturing costs. The complexity of the part design significantly affects tool cost.
Complexities include:
- Multi-stage ejection
- Side actions
- Inclined ejectors
- Up and aways
- Over-moulded inserts
- Unscrewing
- Collapsing cores
- Actuated cores
- Camming cores
- In mould closing
- Interchangeable inserts
- Sacrificial inserts (in high-wear or damage-susceptible areas)
- Fixed half ejection
- Air blast
- Air-assisted ejection
- Cavity pressure sensors
- Valve gates
- Conformal cooling
- Hand-loaded inserts
There are several contributing elements to the cost of a mould tooling solution, which is why it is essential to obtain 'like-for-like' quotations from chosen suppliers.
To obtain a quotation for a plastic injection moulding project and to optimise ROI, contact Pentagon Plastics' in-house engineering team on 01403 264397 or email [email protected].
All tools are quoted and entirely manufactured on-site in the UK; it is even possible to visit and see the tool as it is being constructed.
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