MOULD MAKING PETplanet Insider Vol. 23 No. 03/22 www.petpla.net 18 From R&D+I to producing moulds of label-less bottles Challenge accepted While PET label-less bottles are gaining shelf space and other commercialisation channels, the legal information printed on the container could be less than before. However, the multitude of technical and design resources involved in a label-free bottle make it complex for the mould maker to define in a technical document. It is no longer enough to use a drawing with the code of an etching pattern is shown, solely. Precisely defining textures, glosses, reliefs and other forms of communication involved in a label-less container becomes a necessity for global R&D+I teams. Branding agencies are having more influence than ever on PET bottle design teams. Inevitably, this will require changes in the way designers communicate with engineers at blow mould suppliers. The multiplicity of technical and design resources used in a label-less bottle adds layers of complexity to the way that information is transmitted. The 3D model of a PET bottle contains detailed shape information but a challenge raised by label-less bottles is merging or integrating graphic design resources with industrial design. Engraving texts within a blow mould is not new. Small diameter cutting tools, which rotate at high RPM, have been used until now but the advent of laser technology in mould manufacturing has changed results and greatly expanded possibilities. Is it possible to create exactly the same text if the mould is made using CNC milling machining equipment instead of laser equipment? The answer is: No. A similar result in the blown bottle compared with the laser mould version can, in some cases, change what the branding agency sought to communicate to the target consumer. The beam of light from the laser creates pure shapes on the metal, just like ink on a label, so the logos and fonts are transmitted to the mould as designed – but what happens when a toolmaker changes manufacturing technology from laser to milling machine? Could the shine on the production bottle’s skin not be exactly what was initially achieved in the R&D+I laboratory? And could this ultimately lead to on-shelf performance being affected? Something similar happens with the textures and many other technical resources applied to develop this new high-tech packaging generation. The new design paradigm is associated with the need to communicate more than a shape by the blow mould. Deformations of even a minimal tool radius distort bottle details and, ultimately, the transmission of information. The brand logo, texts, textures, polishing – and more – must be accurate, in order to reproduce every effect that initially was approved in the pilot mould and avoid unexpected commercial results. The success of a NoLabel bottle is not only the industrial design itself, says Juan Manuel Colmenares, Senior Engineer at Moldintec’s TechCenter Buenos Aires. The mould plays a decisive role in creating the effects that make designs legible and attractive, in practice. It brings the virtual into the real world. The use of laser has changed the definition of what we manufacture, as well as the limits of what is possible. The historic corner radius distortion is no longer an issue but getting PET to copy the mould faithfully requires several other factors to be resolved, first. Engineering of the venting channels is an example. Its calculation, location and how they are manufactured will radically influence bottle results. Drilling a hole in a NoLabel bottle is not the same as making a continuous venting frame with the laser, or even combining the two techniques. Something similar happens with textures and fonts. Etching patterns are no longer two-dimensional image applications on a mould surface with a fixed depth. It is now possible to apply specific depths to each part of a pattern and create amazing 3D effects. To make the stunning effects of a NoLabel container, a texture needs a pattern (an image created by designers) but also definitions of density, height or depth, levels of application, roughness, and numerous other fundamental parameters. Companies’ R&D+I teams face the challenge of converting graphic design information into an engineering document. With labels, it is about transmitting the font, the printing colour coding through standards such as Pantone, the technology of printers to be used, the substrate, along with other parameters, to create a label is the same, globally. During the R&D+I process of a novel label-less bottle, several design parameters exceed the 2D drawing and 3D model limits. The techniques and technologies used in the pilot mould must be replicated, in order to manufacture those that will operate at commercial scale in industrial production. This means that they Blow mould shells for label-less mineral water bottles from Danone Villavicencio
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