Although computer-generated simulation has been used for many years to evaluate the structural attributes of a bottle before it is even blown, oftentimes the process stops short.
If you consider that labels are the “hook” by which consumers are enticed to purchase the particular product, it stands to reason that simulation should be expanded to include what happens to the visual attributes once the label is applied to a bottle.
Even though your internal designers or external design house are capable of creating a stunning label, have you given any thought to how what happens to the visual impact should those graphics end up distorted?
Because bottles have frequently been lightweighted, extra ribbing and other structural features are incorporated to create strength attributes to support a thinner wall structure. What can happen in these situations is that visual aesthetics can be impaired by package deformation after filling or storage. Many plastic bottles, particularly in the beverage category, are shrink sleeved which means that every physical detail of the container is visible on the tightly wrapped, stretched material.
For example, important text can become unreadable because it ends up recessed in a structural element that has been added to keep the package rigid enough to handle. What started off as a gorgeous label may end up being much less effective as a brand billboard.
Pouches problematic, too
Further, this situation is not exclusive to plastic bottles. Take, for example, flexible stand-up pouches. When lying unfilled and flat, the graphics are clearly visible. However, when filled, and perhaps gas flushed, pinching can occur along the side seams as well as curving of the front and back panels. What could be clearly read when the pouch is unfilled, could end up distorted or even illegible when the pouch is filled and is standing upright.
Fortunately, technology exists to detect and prevent downstream surprises with modern simulation tools. Although the capability of computer-aided design (CAD) geometry to render with label has been available for quite some time, simulation can now show how far the flexible label can deform in order to conform to the surface geometry of the package. This can aid in selecting an appropriate label material, for example, or designing a bottle in which the label deformation occurs in a non-critical location.
Modern rendering techniques can map the original label on the deformed surface and provide a realistic picture of the final product visually. That means that graphics and text can be repositioned in keeping with the changed mold surface to minimize the distortion. Or modifications can be made to the bottle so that it can be a “friendlier” host to the label.
So, if you are currently not extending your simulation beyond the bottle, you should really consider it. Doing so before the bottle is even produced, can save you significant costs and time-consuming iterations down the road.
Author: Sumit Mukherjee is the Vice President, Advanced Engineering Services, Plastic Technologies, Inc. He has 25 years of experience in preform and container design, materials characterization, process simulation and modeling, and finite element analysis (FEA) for package performance prediction.
PTI is recognized worldwide as a preferred source for preform and package design, package development, rapid prototyping, pre-production prototyping, and material evaluation engineering for the plastic packaging industry. For more information: www.pti-usa.com.
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