FIM

This article was supplied by MacDermid Autotype 

Producing results with FIM

Over the last few years, Film Insert Moulding (FIM) has had a significant impact on the production of high quality mass produced components, from mobile phone handsets to automotive display panels, enabling decorated three dimensional products to be made more quickly, simply and cost effectively than with conventional production methods. What has become clear though is that it is critical that the right materials are  chosen in order to achieve specific results, from a finished component that is scratch resistant to one that can be backlit effectively. This is why the leading manufacturers of film substrates, such as MacDermid Autotype, have developed a range of films specifically tailored to the Film Insert Moulding process.

What is Film Insert Moulding?

Film Insert Moulding is an innovative method of producing decorated three dimensional parts for a wide range of products. As it incorporates fewer stages than conventional methods of component manufacture and in-mould decoration, the time and cost of manufacturing high quality components can be reduced considerably.

FIM involves four steps: printing, forming, trimming and moulding. The necessary graphics are firstly screen printed onto the underside of a special hardcoated film. The printed sheets are then transferred to a vacuum, pressure or thermoforming press, where they are formed to the exact shape of the components being made, with the outer side of film effectively becoming the outer side of the finished component. The sheet is trimmed and individual components cut to size, and each is then inserted in a female injection mould cavity, where molten polymer is injected behind the film, bonding the two materials together to create a solid and finished part ready for subsequent product assembly.

The benefits of FIM

In addition to offering a quick and simple method of producing three dimensional components, FIM provides a number of benefits, including the ability to realise complex high definition designs and produce durable textured parts.
 
As the components can be shaped extremely accurately, with print registration within ±0.2mm, high quality designs can be achieved that may not be possible with alternative production methods. In addition, for products such as mobile phones it is possible to integrate the decorated enclosure and the clear display window into a single component, reducing the materials required and therefore costs.

Furthermore, by printing the component’s decoration on the underside of the film, the hard coated substrate used forms a tough protective skin over the complete surface of the finished part. This makes the component considerably more resistant to scratches and abrasions than those that have been sprayed or have had designs applied to them.

The right materials

Selecting the right materials, and in particular, a suitable film substrate, is essential in achieving these results. The latest films, such as those in the Autoflex Xtraform range from MacDermid Autotype, combine a scratch and chemical resistant, high gloss surface with the ability to be drawn into complex three dimensional profiles.

These films feature a hard coated finish, which enables them easily to resist surface abrasion, wear and possible exposure to solvents and cleaning fluids. This makes the films suitable for use in a wide range of components that are required to withstand daily use and cleaning. Furthermore, the films are UV-resistant to withstand the yellowing effect of prolonged exposure to sunlight, maintaining an aesthetically pleasing appearance over extended periods of time.

In addition, the films offer high levels of optical clarity so that designs can be backlit; for instance in car dashboards or mobile phone covers. Embossed or textured surface finishes are also achievable with the new films.

Perhaps most importantly though, the films have been specially developed to offer consistent results when drawn into three dimensional shapes using FIM. Films can be chosen that offer varying degrees of workability, from those capable of producing shallow formed fascia panels, to others suitable for deep drawn components such as mobile phone covers. Unlike conventional film substrates, these films are able to be shaped without weaknesses occurring or the mechanical properties of the film being compromised, resulting in a high quality uniform finish.

Additionally, the inks used for the FIM process should be chosen carefully, as conventional screen print inks are not generally formulated to withstand the higher temperatures and mechanical stresses imposed during thermoforming and injection moulding.  Many speciality inks are now available, in addition to the range of Aquatex texturing lacquers from MacDermid Autotype, which have been developed to enable a variety of tactile finishes to be applied to the surface of products formed using FIM.

Conclusion

The latest generation of materials specifically designed for use in Film Insert Moulding are now enabling manufacturers to produce three dimensional components for a wide range of products, more quickly, simply and cost effectively than ever before. This availability of specifically designed films and inks, together with FIM now having proved itself in a diverse range of applications, looks set to see the technology grow even further in the near future.