Appliance Design Demands Smart Material Selection
Material selection becomes critical when designing smart surfaces that create a seamless interface.
The Internet of Things (IoT) impacts our daily lives in a myriad of ways that are now commonplace. Connectivity has become status quo as we strive for smarter, faster, better ways of doing things. We have seamlessly integrated our digital and analog lives via wearables, vehicles and appliances embedded with software and sensors that transmit and receive information via the internet. Smart technology works best with smart materials. The next wave of innovation in appliance design will be in the development and adoption of premium polymers that support the human-machine interface.
Materials matter for appliance design
Material selection becomes critical when designing smart surfaces that create a seamless interface. A smart surface can be defined as any surface where an input—touch, voice, etc. generates a response—sound, vibration, light, power, etc. Capacitive touch sensors can be achieved on almost any surface via in-mold labeling (IML), which has been commercially used for nearly two decades as a decorative method. More recently, IML has been used to encapsulate electronic circuits and enable the design of sleek, modern human-machine interfaces. These smart surfaces are often high touch with excess exposure to skin oils and household cleaners driving the need for materials with improved chemical resistance.
Displays are also a key component of the modern-day human-machine interface, enabling IoT applications across markets. Appliance manufacturers who also produce displays are leading the charge incorporating this technology into refrigerators and washing machines among other appliances. New blender designs also incorporate smaller displays to communicate with consumers. The trend of more displays with more surface area is expected to accelerate across industries as consumer expectations continue to grow. Just as with televisions, handheld devices and automotive displays, optical distortion and viewing angle become critical performance requirements for customer satisfaction. Selecting the right materials to be used in the display stack and cover lens can enable a crisp clear image without distortion, thereby improving the customer experience.
The history of the modern home appliance is relatively short but has still seen tremendous improvements from generation to generation. It’s no coincidence that many of these improvements sync with the development of innovative specialty plastics. As polymers continue to improve, so will appliances.
Connected automation benefits appliance consumers
Smart technology in appliances enhances the ability to program, monitor and analyze performance. Smart diagnostics can help identify and recommend optimal settings and send real-time warnings to avoid overloading or misuse. Automatic dispensing of consumables increases efficiency and customer satisfaction. It improves overall performance and prevents misuse, extending the life of the appliance. Smart appliances can automatically reorder consumables such as detergent, parts and scheduled maintenance, increasing customer satisfaction and reducing environmental impact.
The main attribute that will continue to drive consumer sales in large home appliances will remain performance. But consumers are also looking for efficiency, sustainability and elegant design with enhanced functionality such as voice, touch and smart device interaction. That’s at the consumer level.
Further upstream in product development, molders require materials with good flow and low-temperature processing to enable smart surfaces through in-mold electronics and decoration. These surfaces must also be durable without cracking, crazing or fogging over the life of the product. Smart appliances are only smart if the technology works, and material selection is critical for smart functionality.
Smart surfaces face challenges
IML with in-mold decoration and electronics can produce seamless human-machine interfaces that disappear into the design of an appliance. Challenges arise in building up the layers of film to accomplish the interface. In particular, electronic or conductive inks, typically silk screen-printed to ensure durability of the circuitry, contain metals such as silver, gold, copper or indium tin oxide. Therefore, they don’t tend to stick to anything and can easily wash out during injection molding of the IML substrate. Commonly, inks are the thin material encapsulated for aesthetics, but metals and films are also in use for both aesthetic and functional purposes such as sensors, holograms, lenticulars, electrical circuits and electromagnetic radiation (EMR) shields.
Materials with good adhesion to these conductive inks, low temperature processing and high flow are required to prevent ink wash out. These materials generate low shear stress and shear heating in the melt state due to their high-flow capabilities at low temperatures lowering scrap rates and enabling higher yields in this complex process. With 10-15 layer stacks necessary to achieve advanced functionality, there can be substantial yield loss during the buildup process contributing to higher costs.
Considerations for dimensional stability differences between the substrate and film materials are also important. If there is a significant difference in rates of expansion between the substrate and decorative/electronic film, then shear stress will be created at the boundary layer and delamination or broken connections could occur over time.
Lighting can also be incorporated into in-mold electronic film stacks with directional light-emitting diodes (LEDs). The firing of LEDs can be masked with ink to prevent photon leakage across multiple windows.
Decreasing haze can improve the appearance of the IMD part. Haze is measured as the percentage of light scattered through the plastic part. Haze can be caused by surface impurities in the decorated overlay and the formation of crystallinity in the substrate. The lower the haze value, the higher the clarity.
Popular methods of decorating plastics can be broken into two categories based on the location of the decoration—on the surface or encapsulated. Surface decorations are directly exposed to the environment while encapsulated decorations have a clear protective layer that limits direct-decoration exposure. Encapsulated decorations do not provide complete protection, since degradation from light, heat and permeation occur. However, the rate and sources of degradation are substantially better than surface types. Encapsulated decorations are selected when greater durability is desired.
The toughness of the plastic enables the part to better withstand substantial impact and deformation. Clear substrates are required for in-mold decoration (IMD) parts that contain display windows for such things as digital displays and backlighting. If display windows are not needed, these polymers can be tinted or colored as desired. Overlay and substrate durability ensures long-term performance that’s critical when using IMD technology—the plastic and the decoration must be complementary.
Where the smart things are
Forty percent of IoT products have to do with business and manufacturing, used in real-time analytics of supply chains and equipment and programming robotic machinery. Thirty percent are used in portable health monitoring, electronic recordkeeping and pharmaceutical safeguards. Just over eight percent are deployed in retail applications such as inventory tracking, smartphone purchasing and anonymous analytics of consumer choices. Nearly eight percent of IoT products are designed for the security business with biometric and facial recognition locks and remote sensors.
The rise of in-home service with technologies like Amazon’s Alexa and Google Home will spur demand for appliances that work together. Connected washing machines are projected to reach 11 percent penetration by 2020. The rise of the “Connected Consumer” is a global megatrend by which digital connectivity has enabled consumers to free up time, simplify life and reduce stress. This digital wave shows no signs of cresting.
Smart opens up strategy gaps between brands
Smart materials are another way to find points of differentiation and create value for consumers. Manufacturers who pursue innovation using novel materials to develop solutions that meet and exceed customer expectations will ultimately prevail. Next-generation smart products will be made from polymers and compounds that are clear, tough, chemical-resistant and easily processed. Acoustic material properties are important to improve sound quality and clarify voice-activated devices. BPA-free plastics are essential for devices that come in contact with food. The secret to success in designing and producing new-age appliances lies in collaboration with channel partners across the whole value chain. This list may include designers, molders, distributors, brand owners, retailers and yes, even consumers. It is this close collaboration and sharing of technology that will allow the plastics industry to meet and exceed the needs of an ever-changing marketplace.