In-Mold Labeling and In-Mold Decorating
Let’s begin with a definition:
In-mold labeling (IML) or in-mold decorating (IMD) is a process of decorating or labeling injection molded plastic parts or components during the plastic injection molding cycle. The label becomes an integral part of the final product, creating a fully decorated item at press. In this process, a pre-printed label or decorated film is inserted in the open plastic injection mold and held in place via vacuum ports, electrostatic charge, or other method. When the mold is closed, plastic resin is injected into the mold, encapsulating the label permanently within the finished part.
In-mold labeling (IML) was first used in the mid 1970’s as an alternative to decals and pressure sensitive labels. Early adopters quickly realized the benefits of in-mold labeling extend across multiple areas of the business, from enhanced design options and message durability to manufacturing efficiency and improved supply chain management. In-mold technology enabled a significant shift in the labeling and decoration of plastic products. Because parts were now removed from the injection mold fully decorated, manufacturers eliminated additional costly and time consuming post process decoration. Not only did this technology remove the necessity for a separate process, but it allowed manufacturers to move this entire process to their injection molder. Although IML has become prolific in some industries, certain limitations have prevented some manufacturers from deploying this process. Recent advancements have lifted most of the limitations and created new opportunity for these manufacturers. In-mold technology has advanced significantly since its infancy. Current innovations in three-dimensional (3-D) IML have expanded capabilities and opened in-mold decoration to new product types, allowing the benefits of cost savings and manufacturing efficiencies across nearly all industries. This now provides manufacturers endless options to replace metal forms, painting, dipped coatings, pad printing, and other post production decorative techniques with a durable, high quality, single step label that creates a fully decorated resin part right in the mold.
The Difference between IML and IMD
In-Mold Labeling vs. In-Mold Decorating While IML and IMD are often used interchangeably, the industry draws a very specific distinction between the two: IML is most commonly used on disposable consumer packaging on products with a short life span, such as food containers, cosmetic and personal care containers and household product containers. It is employed in high speed, thin walled, multi-cavity injection mold machines. The labels are usually printed on polypropylene foils only a few tenths of a millimeter thick. Life span of the product is measured in months, not years, and the cost of the labels is low. IMD is most commonly used on durable products with long life spans, such as appliances, toys, medical devices, automotive components, lawn and garden equipment and other durables. It is employed on thick walled, lower cavity injection mold machines. The label material varies as does the thickness in order to meet the durability requirements. Life span of these products is measured in years, not months and the cost of the label is medium. These labels enhance the product aesthetically, communicate important safety information and represent the brand.
Combining the decoration process with the molding process adds durability, decreases manufacturing costs and creates design flexibility.
DURABLE – graphics are impossible to remove without destroying the plastic part and will remain vibrant for the life of the part. Options are available for enhanced durability in harsh environments and chemical resistance.
COST EFFECTIVE –eliminates post-molding labeling, handling and storage. It reduces WIP inventory, and the additional time required for post-production decoration, on-site or off-site.
FLEXIBLE DESIGN – available in a wide range of colors, effects, textures and graphic options and can replicate even the most challenging looks like stainless steel, wood grains and carbon fiber.
IMD requires proper mold design and construction for accurate placement and reliability, and often employs robotic automation as part of the process for increased speed and accuracy. This involves up-front investments that are typically repaid over the life of the product. Traditional IML/IMD is best suited on flat surfaces with very low depth of draw. Limitations on 3-D applications include:
- Labels fold and crease
- Gate wash
- Distortion of image/windows
- Inks crack
- Very shallow depth of draw
- Must match film to resin
- Not compatible with appliance resins (poor adhesion)
While IML/IMD is a high quality, efficient, durable and cost effective form of labeling plastic, alternative methods are employed to compensate for the above mentioned limitations. Traditional decorative methods also create a quality product, but each comes with limitations and costs of their own. The following outlines traditional methods of decoration including their pros and cons
A New Dimension for IML/IMD: 3-D
The recent introduction of 3-D IML/IMD has created new design possibilities by enabling the use of high quality visuals across surfaces, regardless of texture, shape or dimension. Advancements in film technology enhance the formability of these labels, increase the depth of draw, dramatically increase durability, and prevent image distortion across dimensional edges. This truly revolutionary product can change the way products appear more than any decoration technique introduced in the past 20 years. Because 3-D parts have multiple angles and textures with varying depths and surface angles, it is critical that any new technology meet these application requirements. 3-D IML/IMD not only meets these requirements but outperforms existing technologies in most instances. Highly curved surfaces, textured surfaces, and deep cavities are easily achievable with 3-D IML. Thermoformed products can achieve depths of draw of several inches, and tight radius and sharp curves are achievable with the correct substrate selection. Nearly any shape or size can now be considered for this technology, opening doors for design and engineering to leverage IML/IMD for any product. The advancement of films that has enabled 3-D applications of in-mold technology has also significantly increased the durability and longevity of these labels. With a life span increase of more than tenfold over traditional IML, these labels are now even more suited for communicating brand and safety messages on durable goods with long life spans in harsh outdoor applications and even chemically abrasive environments. Image distortion, especially on curved surfaces and around corners has long perplexed IML manufacturers. However, advancements in image design and printing technology have solved for this problem. Skilled digital design combined with the latest in proprietary printing inks and equipment have finally overcome this long standing obstacle to create crisp, clear visuals that don’t distort around curves. Furthermore, the look of brushed metals, chromes, wood grains, paints and coatings, carbon fiber and nearly any natural or synthetic finish can now be achieved in any shape with 3-D IMD. These proprietary inks and decorative laminates create stunning visuals with hundreds of new options for designers. These new capabilities eliminate the previous limitations of IML/IMD and enable manufacturers to explore the cost and operational benefits of IML/IMD on their products.
IML/IMD provide greater decorating options than most other labeling and decorating methods. Until recently, 3-D products were unable to benefit from the enhanced durability, lower manufacturing costs and elimination of post-process decorating. Innovations in film and ink technology have opened IML/IMD to these products and manufacturing methods. With increased depths of draw, increased formability and no image distortion, manufacturers should reevaluate using IML/IMD on injection molded components.
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