In-Mold Electronics Processes Show Promising Results for Speedy 3D-Shaped Design Development

July 16, 2020 by Gary Elinoff

In-mold electronic devices will emerge as a significant trend in electronic manufacturing.

Developing in-mold electronics (IME) involves a multifaceted process that involves integrating electronics into the plastic casing that will form the final product’s exterior. Printing electronic circuitry onto a 2D substrate is the starting point. Then, the challenge is to build a functional 3D part around the circuit, which must survive functionally intact within the encasement.

There is a myriad of challenges and many market participants. IDTechEX outlines these, and the potential of IME, in an authoritative report.


Inks Critical to Success

The conductive inks used to paint the circuit traces are central to IME success, as they are the foundation of the embedded circuit board of any IME product. These inks need to be sturdy and, above all, flexible enough to survive the forming and molding steps. 

The inks should also be highly conductive, which will allow for thinner lines for a given conductivity, which allows for greater stretchability.

Similarly, all the adhesives must support some degree of elongation, as the 2D substrate is bent, shaped, and formed to the final 3D structure. This is critical for mounting rigid connectors or ICs near to locations that are curved.


Substrates and Solder

The substrate material most commonly employed in IME designs is polycarbonate (PC). This material, while highly formable, is relatively expensive.

An emerging trend is to use Polyethylene Terephthalate (PET), which is not quite formable but adequate for designs with lower curvature radii. PET, however, can’t tolerate high heat, but low-temperature solders are being developed.


In-mold electronics prototype.

Products and prototypes made possible by In-Mold Electronics. Image credited to IDTechEx


Reliability Takes on Even Greater Importance

Reliability in the IME processes is of vital importance, because the electronics will, by definition, be encased within the plastic, and there will be no opportunity for post-deployment repair. Perhaps the first commercial implementation of IME came in a Ford vehicle in 2012 in an innovative overhead console.

As IDTechEx reported, the product failed, and it was an expensive, highly visible failure that was a significant setback to the acceptance of IME. It has been speculated that the failure was due to moisture ingress into the plastic package. 


Market Development

Even though the relevant technologies have advanced since 2012, up to this point, the industry has generally sought to avoid another “bridge too far,” with the subsequent iteration of IME progress largely devoted to electronically simpler products. IDTechEx expects that in the near-term, the emphasis will be on automotive components.

One prospect is the heaters embedded in light covers for external automotive LED lighting, necessary to effect defrosting when low-heat, energy-efficient LED lights are employed. An HVAC control panel is envisioned for automotive interiors that will be ensconced within an aesthetically pleasing 3D shape. 

The next step will be, again, for more complicated designs. Prototypes that incorporate NFC antennas, multiple LEDs, and light guides are becoming more popular. Significantly, designs incorporating multiple touch switches have also emerged.

It’s reported the IME will be incorporated within major appliances (white goods). Undoubtedly, wearables are a natural target for IME manufacturing. Rumors abound, but no definitive announcements have yet been made. 

Expectations for the Future

It is expected that the market for in-mold-electronics will show significant growth beginning in the 2023 to 2024 time frame. The movement will start with simple small-area devices and then progressing on to more complex, larger-area applications. In time volumes will increase, with a particular emphasis on stringent reliability.