Toolmaking

We have years of experience in toolmaking. Our bespoke moulds facilitate the production of new and innovative solutions.

Mould design and manufacture can be a complex process with many aspects to consider. Due to the manufacturing process involved it is important to clarify as many key characteristics of the moulded parts as early as possible such as critical dimensions and critical surfaces. Equally, small changes in the design process can provide added value in later production that ensure moulded parts are as effective and successful as possible.

Polytech Mouldings has worked hard to deliver a broad spectrum of options for our customers and encourages an open and detailed conversation with our sales team to ensure the right option is chosen, and in turn meet the requirements of the part’s application, usage and quality requirements.

Polishing & Surface Finish

Once the profile of a particular mould tool has been completed, post polishing can be completed to achieve a more consistent or higher specification of surface finish. For certain parts polishing is also used as a way of improving the moulding process by reducing surface friction while demoulding. In general, most moving sides of a tool require a line of draw finish to aid the ejection of the plastic part off the mould.

The level of polishing on moulds is defined by the SPI scale. There are 12 grades of mould finish ranging from mirror perfect to dull with SPI-A1 being the highest specification.

In general, the higher the surface finish required, the greater the polishing time involved and therefore cost in tool production. Some polishing standards require the moulds to be manufactured from certain grades due to their reaction to polishing materials. Unless requested, Polytech Mouldings tooling quotes are unpolished by default.

As well as varying levels of gloss finish, there are a number of graining preparation options for parts that require a textured finish. This is usually a very specific request linked to the application of the parts or to replicate a more traditional material such as leather.

Due to the variance between materials, some moulded parts will appear slightly different to others even though the surface finish of the mould is polished to the same specification. For example, polypropylene components will appear glossier than TPE parts from the same highly polished mould. Where matching an existing finish or reaching a certain specification is critical, samples can be provided in advance of finalising tooling options.

Identification Marks & Engraving

As part of our bespoke service we can incorporate company branding, identification marks and product/part references into your mould.

The marking and identication of tools and components can be advantageous in stock management and rotation, batch control and traceability.

Date stamps and labelling allows greater batch control as moulded parts can easily be linked to the date of manufacture. Various options include month and year of production, which will link to specific production notes.

Polytech Mouldings also incorporates material or application specific marks which are integral to the part in question. For example: Food Safe, Recyclable, Recyclable/Material Identification, CE Markings. Registered and Trademark markings are also available.

Company branding is increasingly critical in retail and consumer applications. It is also important to protect intellectual property rights and/or research and development investments.

The addition of a company or product logo/name is an important design consideration. Depending on the product itself, these additions can be sunk in to the part or raised on the surface. As such, these considerations need to be incorporated in to the mould design at the earliest stage possible.

For consumable parts, or those used in engineering or manufacturing applications , product reference numbers can often be critical to ensure the correct option is used as a replacement part, maintaining integrity of supply.

If you have specific requirements we are happy to discuss these with you.

Mould Materials

Tool design for injection moulding requires the consideration of many key factors. In material selection it is critical to understand the surface finish and volume requirements of the moulded part.

Steel

An extremely broad material choice for Injection Moulding tools is steel. The variety of grades available give flexibility to select an option more suited to machining (where specific profile details are complex), more suited for polishing (where the surface finish is critical) or more suited for longevity (where production volumes are likely to be very high).

As a general rule, the harder the steel grade the longer it takes to machine the cavity of tool, resulting in higher tooling costs but a higher quantity of components that can be produced without maintenance of the mould.

Where surface finish is more critical, high quality stainless or hardened steel produce the best finish and result in highly polished parts. Lower grades are suitable for spark eroding where a textured or matt finish is required.

Aluminium

Aluminium can be used as a more economical alternative, mainly due to it’s ease of machinability rather than the actual material cost. This ensures faster production of the tool in comparison to steel and often more flexibility in profile design.

Polished finishes can also be achieved quicker due to the softer nature of the material. Aluminium mould tools heat up quicker than steel making it more suitable for very low production runs.

Although aluminium tooling is generally seen as more suitable for lower production quantities, as a specialist “soft-plastic” moulder, Polytech Mouldings also uses it as a viable option for full production runs on materials such as TPU’s and TPE’s. Thousands of production parts are manufactured from aluminium tooling.

CAD Modelling

Using Solidworks 3D modelling software we finalise production design from drawings, sketches, or samples. We have the software capability to work with file formats including:

• STEP
• IGES
• DXF
• Photoshop (.psd)
• Illustrator (.ai)
• Solidworks part (.sldprt)
• Solidworks assembly (.sldasm)
• Solidworks drawing (,slddrw).

The upfront cost of a new mould can be a big commitment, and it is crucial that the design is right. Utilising innovative 3D printing technology, we can offer a high- quality prototyping service before final mould designs are sent to production.

3D printing enables us to produce complex yet functional shapes using less material than traditional manufacturing methods. Once prototypes are approved, final mould production begins.

3D Printing

Our Ultimaker 3 3D Printer enables us to utilise innovative technology to offer a high-quality prototyping service for existing and new customers, as well as start up projects. We are able to produce complex yet functional shapes using less material than traditional manufacturing methods.

3D printing, also known as additive manufacturing, is a process of making three dimensional solid objects from a digital file. The creation of a 3D printed object is achieved using additive processes.

In an additive process an object is created by laying down successive layers of material until the object is created. Each of these layers can be seen as a thinly sliced horizontal cross-section of the eventual object.

Ultimaker 3D Printer

The Ultimaker 3 3D Printer combines a high level of design complexity and freedom with a wide material portfolio, specially formulated to create industrial grade prints.

The Ultimaker 3 Extended works alongside the market leading Ultimaker Cura software which features the optimal preconfigured settings for Ultimaker printers and materials.

We also utilise Solidworks 3D modelling software to finalise production design from drawings, sketches or samples. We have the software capability to work with file formats including STEP, IGES, DXF, Photoshop (.psd) Illustrator (.ai), Solidworks part, (.sldprt), Solidworks assembly (.sldasm) & Solidworks drawing (,slddrw).

The fully integrated system of hardware, software and materials ensures that we can deliver the entire professional 3D printing service.

Design Considerations

There are a number of critical considerations to be taken into account when designing or modifying a mould and our technically experienced team can help you make the right decisions for your individual requirements. It is important to consider your future production requirements as there is a direct link between cost effective tooling and the value of subsequent parts.

Technical design considerations may include:

Side Actors : For parts where there are negative angles (details that are perpendicular to the axis of mould opening) side actors that move outwards as the mould opens may be necessary to allow the part to be de-moulded. These add to the moulds complexity and cost but are not always required. They are dependant on the design of the part and the rigidity of the moulded material and can sometimes be formed by negative steps in the fixed or moving halves.

Ejector Pins : Moulded parts, particularly those produced in hard materials such as nylon, will often need assistance in releasing themselves from the mould. Often, we will use ejector pins to push the part from the mould as it opens. This can sometimes leave small circular impressions in the moulded part.