Plastic Injection Moulding Specialists. Est 1948.

At S.B.Weston we will always encourage prototyping of your product in order to realise design aspects which can not be fully appreciated through computer rendered models. Prototypes are valuable for gaining an insight into how the product will perform and what its limitations and weaknesses may be. Understanding problems from a prototype allows the design to be easily be amended well in advance of tool production.

There are many available prototyping methods. We can machine plastics, wood or metal and where possible we will always work in the same materials as the intended final production version. Ensuring that the functional and stylistic aspects of the prototype are acurate to the production version is of optimum importance.

We transmit CAD information from files supplied by our designers, directly into our HERCO CNC milling machine allowing us to work on prototypes very quickly and accurately.

There are certain types of product where we will use Vacuum Forming instead of the traditional milling from a solid process. The process is most commonly used to produce product packaging using a material such as HIPS High Impact Polystyrene but is also very effective for many types of prototypes.

In the past we have manufactured prototypes using methods such as  Stereo Lithography.

Let us visualise your idea!

S.B.Weston’s design team can provide you with a technical drawing service using the latest CAD software.

Our designers will work with you to evolve and improve your product idea aesthetically and functionally creating 3D models and detailed drawings to visualise your idea on screen.

To ensure your product can be successfully transferred to a mould tool which moulds, ejects and generally performs correctly and consistently at the manufacturing stage, the following design considerations will be applied:

• consistent wall thicknesses throughout the design.
• thin walls to allow consistent cooling and reduce uneven material
• shrinkage.structures such as ribs utilised to strengthen walls.
• ribs – half the wall thickness to avoid sinking.
• corner and edge radii.
• draft angles added to sides (typically up to 2 deg) – especially textured /spark eroded walls and walls higher than 1.5cm.
• no undercuts that are impossible to remove from the mould unless absolutely necessary – undercut features nescessitate side core actions which significantly increase the complexity and cost of the mould.
• light colours and spark eroded finishes to hide flow patterns.
• keeping holes at least .0.75cm from edges.

Once these criteria are met we will look for a design approval from you, at which point the CAD files will be supplied to our toolmaking staff for prototyping or CAD/CAM tooling purposes.

Remember… Design will make or break a product… come to the professionals!

Process
The basic principal of injection moulding is to fill a metal mould or ‘tool’ with molten plastic. The molten plastic, when injected into the mould tool under pressure, will take the shape of the mould cavity. The plastic cools, becomes solid and remains in the shape of the mould cavity. It is then ejected from the mould ready for packaging.