Patterns and Moulds

Composites are lightweight and strong, making them perfect for a variety of needs.

What is a pattern?

A pattern is a term used to describe the negative of the final product – or in simpler terms, a mould without any plastic. To make this initial pattern requires specialist equipment and years of industry knowledge.

Once you have decided which style, colour and size is required for your product, it will be necessary to create a 3D CAD (computer-aided design) image, which will allow the pattern to be created.

You may decide to outsource your initial patterns, and some companies do indeed benefit from this. However, if you wish to manufacture and produce the highest quality products, you should design and manufacture your own patterns.

This is one of the stages within mould manufacture where Swift Composites excels, due to the fact that we design and make our own patterns in-house. This ensures that the best materials are used and that they are designed by an expert who has vast experience in creating products for high-volume manufacturing. If you require more information on this stage of the process, don’t hesitate to get in touch with us.

Moulds are only as good as their patterns, so if you are considering outsourcing your initial patterns, make sure that experts make them with the required skills and experience of pattern design. Otherwise, you can end up with faulty products or longer lead times.

Pattern/plug making

A pattern maker will create a “positive” model from which a metal, wood or plastic-based tool can be produced. This ‘pattern’ is used to create the cavities in the mould tool. As each cavity is unique, they are all made separately and then brought together (known as clustering) on the final mould.
It is important that the original pattern is retained throughout this process; otherwise, it will be challenging to ensure that all cavities within the mould are identical.
The process of pattern making is made up of the following stages:
1) Carving – This is where a block of wood, metal or plastic is carved to shape using specialist tools such as chisels, cutting knives and files. These can be either handheld or power-driven. Depending on the material used, various tooling may be required, such as a hand-operated coping saw for wood.
2) Assembly – Once the pattern has been carved to shape, it is essential that it can be held in one piece. This requires a great deal of skill and knowledge on behalf of the pattern maker, who must have a thorough understanding of strengths and weaknesses in different materials. For example, a wooden pattern will be held together with a wooden ‘core’. The core can either be glued or nailed.
3) Preparing for moulding – Whether the pattern maker is carving manually or using a machine, they must also ensure that all of the necessary holes and sleeves are in place before moulding can take place. These include the sprue (where the resin will be injected into the mould), vents (used to allow air to escape during the moulding process) and runners (used for metal moulds). These must all be in place before moulding can take place; otherwise, the final product may fail.
4) Finishing – The edges of a pattern are usually sanded to remove roughness and give the part a finished look. The pattern will then need to be checked for accuracy with gauges; otherwise, this may lead to imperfections in the final tool.
When purchasing a new product, it is important to incorporate an element of customer service into your decision-making process. When buying moulds, it is worth checking whether your supplier offers a repair service. This can be useful as moulds are almost certainly going to need repairing at some point during the life of the tool, and if not offered by one supplier, then look for another who does offer this service.
Where a product fails, it is essential that you have a good manufacturer who can turn it around quickly. It is worth checking the mould manufacturer’s timescale for this process and looking at what support they offer throughout different stages of the tool’s life.

What is the process for manufacturing a mould?

Before designing the mould certain measurements must be taken that include; wall thickness, gate location, draft angle and shape. The design process then involves creating all the surfaces required to form the desired shape. Once this has been completed calculations will need to be performed on those surfaces to ensure that they are structurally sound, before finally creating the parting line.

Once the pattern has been completed it will need to be tested for functionality by running trials in order to ensure that everything functions correctly.

What are tooling/moulds and why is it important?

Composite parts are made in moulds, also known as tools. Composite materials can be used to make robust tools for low or high production of parts and the cost of the tool will depend on these factors. For lower volume applications such as prototype parts, less expensive soft tools can be used which do not need to be made from the same materials as hard tools.

We will examine what composite moulds are and why they are important for composite production companies, including the benefits of using composite moulding over other material types such as aluminium or steel.

What is Composite Tooling / Moulds?

A tool, also known as a mould, is a block of material such as aluminium or steel which is used to produce composite parts. Depending on the application and production volumes, tools can be made from many different materials to match the strength requirements for each component.

Why are Tooling / Moulds important?

There are several reasons why tooling (moulds) is important for the production of composite parts. Firstly, it is used to shape composites into the required shapes and allows mass production of components rather than individual ones or small batches which are cost-prohibitive due to the time it takes to make them by hand. Tools also allow for different materials (types) of composites to be combined in one tool allowing for a combination of properties required in the final part which is not possible with just one material type.

How are Tooling / Moulds made?

There are several ways that tools can be produced depending on the end goal and application of the tool. For soft tools, a process called transfer moulding is used to produce a finished tool which is then used to produce parts. The mould can be made from a variety of materials but soft, low-cost foams are often used due to their quick production time and ease of use. Hard tools can also be custom machined from raw materials to produce the desired shape of the part. After the tool (mould) is made, it is filled with a material such as resin or metal and allowed to cure. This results in a finished component that can be used for production.

Benefits of Composite Moulding over Metal or Steel Moulds

One of the main benefits of using a composite tool over a metal or steel mould is the overall cost. Oftentimes, composites tools can be more than 50% cheaper to produce due to the quick production time which allows for more efficient use of materials and lower labour costs on non-skilled jobs such as cutting materials.

In addition to being cost-effective, lightweight, corrosion-resistant and low-maintenance, composites tools can be used to produce lightweight parts with high stiffness (strength to weight ratio).

Tooling (moulds) that are produced using composite material can also accommodate integrated components within the tool. For example, inserts which are placed inside the tool to provide specific functions such as an area where the adhesive can cure.

Tooling (moulds) for composite production can also be tailored to the end goal of the part. For example, different materials (types) of composites (i.e. glass, carbon etc.) can be used on each side of a traditional metal or steel tool to produce parts with specialized properties which are difficult with only one material type.

For low volume applications where soft tools are used, they can be produced cheaper than CNC machining of aluminium.

Tooling (moulds) made out of composite materials also do not need the same level of post-treatment after production is complete. This means that they can be installed and used quickly in the production process, whereas metal or steel tooling (moulds) which need to be post-treated such as heat treatment, surface treatments and paint.

Check out our other pages: Custom composite mouldings, precast composite moulds and why use composites.

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