To bring any new plastic injection moulded component to market you must first invest in a mould tool. The mould tool will become the very heart of your on-going volume production which is why it is so importance to source a supplier that is reputable, quality assured and pro-active.
Investing in bespoke mould tooling is expensive and making such investment at the start of a project you want to know that your tool is being created by specialists that you can trust.
Mould tool manufacture is a technical and complex process and includes several stages.
Product and mould design
Review the component CAD model and specifications.
Decide mould type: single/multi-cavity, family mould, hot runner/cold runner, etc.
Design the mould around parting lines, draft angles, cooling, ejection and material flow.
Utilising CAD/CAM software produce detailed mould and component drawings.
DFM (Design for Manufacture)
Check whether the component can be moulded reliably.
Identify issues such as thin sections, undercuts, sink marks, weld lines and difficult ejection.
The tool designer may recommend changes to your component design before manufacturing begins.
Steel and component selection
Select the appropriate tool steels for mould plates, cavities and cores.
Common choices depend on required tool life, plastic material, surface finish and production volume.
Sourcing or manufacture of standard mould components including ejector pins, guide pillars, bushes, slides, lifters, etc.
CAM programming and machining
Steel blocks are cut to size and machined using CNC milling.
Complex cavity/core surfaces are produced through roughing and finishing operations.
EDM (electrical discharge machining) is often used for deep, narrow or intricate features that are difficult to mill.
Wire EDM can produce precise profiles and slots.
Heat treatment
Certain tool steels are hardened or otherwise heat treated to achieve the required hardness and durability.
Subsequent grinding may be required to restore precise dimensions.
Grinding and precision finishing
Surface and cylindrical grinding brings critical dimensions and flatness within tolerance.
Fine polishing may be required for cosmetic mould surfaces.
Texturing or specialist surface treatments can also be applied.
Mould assembly
The individual plates, cores, cavities, slides, lifters, ejector system, cooling system and other components are assembled.
Critical clearances and alignment are checked manually and using inspection equipment.
Inspection and measurement
Components are inspected using equipment such as CMMs, height gauges and optical measurement systems.
Dimensions are checked against the CAD model and drawings.
The assembled tool is checked for movement, alignment and mechanical operation.
Tool Trial_T0
The completed mould is installed in an injection moulding machine.
An initial trial, often called ‘T0’ is performed to establish whether the mould produces acceptable parts.
Process parameters such as injection pressure, temperature, cooling and cycle time are adjusted for optimisation.
Tool correction and optimisation
Trial parts are inspected.
If there are dimensional, cosmetic or moulding problems, the toolmaker will modify the mould.
Further trials (T1, T2, etc.) may be carried out until the tool meets the agreed requirements.
Final approval and delivery
Final samples and inspection reports are provided to the customer.
The mould is cleaned, preserved and should be serviced between runs for ease of on-going production.
Due to the extensive complexities involved and the level of financial investment required working with a trusted supplier is imperative to ensure return on investment. UK mould tool manufacture can be expensive compared to costing from overseas suppliers due to several reasons including lower overhead costs, lower labour rates, economies of scale in the tooling industry among other contributing factors. However working with a UK supplier delivers ease of communication, no shipping and import costs, ease of supply chain and confidence in tool life and steel specifications ensuring longevity of your tooling solution.
