Aesthetics vs. Functionality in Circuit Design? In-Mold Electronics Eliminates the TradeoffJuly 15, 2020 by Jake Hertz
An emerging field in electronics manufacturing may provide lightweight and cost-effective solutions to meet design constraints. But it's not without drawbacks.
When designing electronics projects, one of the major considerations that must be taken into account is the desired enclosure. All designers want to create something with an aesthetically pleasing user interface.
Product designers will design this interface and then give an EE specification: they must fit their design—circuitry, wires, batteries, and all—into a given area. This often represents a tradeoff between aesthetics and functionality.
Example of a product utilizing in-mold electronics. Image used courtesy of InMold Solutions
An emerging technology called in-mold electronics (IME) looks to alleviate this issue, giving engineers lighter, cheaper, and more compact solutions to manufacturing.
In-Mold Electronics: What Is it and How Does it Work?
In-mold electronics is a manufacturing process that incorporates printed electronics, 3D forming, and molding to create 3D objects with embedded electronics.
This technology is achieved by first printing multiple layers of decorative, electrically-conductive dielectric inks on thin plastic films. After being fitted and thermoformed, these films are loaded into plastic injection molding tools. It is then over-molded, encapsulating all circuitry and graphics. Later, more surfaces of printing circuitry introduce the design with touch controls, lighting, and other desired functionality.
The manufacturing process of in-mold electronics. Image used courtesy of Design HMI
The result of this process is a rigid plastic with the electronics thinly embedded onto its surface.
The Benefits of IME
This technology can offer a plethora of benefits to both designers and manufacturers. The original issue of a space-functionality tradeoff is resolved. Circuits that mold to the enclosure provide EEs with higher degrees of freedom and less spatial restrictions in their designs.
According to Design HMI, this technique can also make designs up to 70% more lightweight by removing the need for PCBs and clunky human-machine interfaces (HMI) such as mechanical switches and sensors. In addition, IMEs can help designers save on costs, too, because it requires fewer wires, components, and other raw materials; it also has a simplified assembly process.
Example of an IME user interface with one backlit icon, six LEDs, and ten cap-touch switches. Image used courtesy of Design HMI
Compared to traditional manufacturing techniques, IMEs also benefit designers with higher reliability. Less moving parts, fewer manufacturing steps, and total enclosure of the circuitry means less chance of wear and eventual failure.
Potential Limitations of IME
Despite all the benefits, there are still challenges to be faced when utilizing IME.
For starters, structurally-embedded electronics are highly irreparable, as an IDTechEx report points out. Compared to traditional manufacturing techniques that allow electronics to be repaired when damaged, IMEs need to be replaced when damaged.
On top of this, there are many hazards in the manufacturing process. First, the conventional silver material used as a conductor is also very susceptible to cracking during the thermoforming process due to the immense heat. There have been developments in material science to help fix this, but it remains a problem nonetheless.
Example of conductors cracking after thermoforming. Image used courtesy of DuPont and Design HMI
Furthermore, the high pressure utilized during the molding process can compress any gas trapped inside electronic packages, leading to deformation or detaching of the surface-mounted devices. The same deformation or detaching can be caused by the heat of the injection molding process.
In-Mold Electronics Face Many Possibilities—And Hurdles
In conclusion, in-mold electronics offers some serious benefits when it comes to designing spatially-efficient electronics. The technique can help save designers money, provide maximized reliability, and help eliminate the tradeoff between functionality and aesthetics.
These benefits, however, do not come without their drawbacks. Many technological and material science-related hurdles still must be overcome before this technology can become mainstream. When these challenges are solved, many industries should reap the benefits.
Do you ever feel like design aesthetics and functionality is a balancing act? Or do you primarily focus on functionality? Share your thoughts in the comments below.