In-Mold Electronics

In-Mold Electronics (IME): Printable Materials for 3D Molded Circuits

In-Mold Electronics (IME), also known as In-Mold Structural Electronics (IMSE), is a technology for seamlessly integrating lightweight electronics into 3D molded components such as smart surfaces in automotive, aerospace, and white goods such as washing machines, tumble driers, and dishwashers.

IME is a multi-step process in which stretchable electronic advanced materials are screen printed onto plastic film, thermoformed to create 3D structures, and then encapsulated by injection molding to provide highly durable, lightweight electronic components. At Dycotec we work in close collaboration with OEMs as well as tier 1 and tier 2 designers and manufacturers to provide the complete product portfolio of advanced materials for In-Mold Electronics.

What Is In-Mold Electronics (IME)?

In-Mold Electronics is a manufacturing technology in which electronic circuits are screen printed onto flat plastic film using conductive and insulating inks, populated with components, thermoformed into a 3D shape, and encapsulated by injection molding. The result is a single molded part with integrated electronic functionality such as capacitive touch, switching, lighting, and printed resistors, replacing conventional assemblies of rigid PCBs, switches, and wiring.

Examples of In-Mold Electronics

Lighting Application for Automotive

Working with the Centre for Process Innovation (CPI), Faurecia (now FORVIA), and Xandor, Dycotec Materials supplied the silver, carbon, insulator, and electronically conductive and structural adhesives to demonstrate an innovative lighting proof of concept. Lighting is key to the branding and identification of automotive manufacturers, as well as providing the driver and passengers with a safer and more pleasant experience.

The design was developed to showcase how innovative lighting structures could be produced for the automotive sector. Designs were developed by automotive tier 1 Faurecia (now FORVIA); screen printing, assembly, and thermoforming were undertaken by CPI; and the final device was molded by automotive tier 1/2 supplier Xandor.

The benefits of In-Mold Electronics demonstrated by this case study are numerous:

Novel thin form factors that conform to the component design (for example automotive interior lighting or consoles), allowing greater design flexibility and up to 70% lighter construction than traditional electronics assembly.
Superb durability, as the circuits are encapsulated in a resin mold.
A more environmentally friendly process: IME is more than 70% more sustainable than conventional electronics technology, using less material and allowing the use of recyclable plastics.
Seamless integration with graphic printed layers, creating aesthetically pleasing components.
Builds on cost-effective, well-proven production facilities already developed for In-Mold Decorating (IMD) and In-Mold Labeling (IML).
Reduced cost: fewer manufacturing steps and easy incorporation of electronic functionality such as capacitive touch, switching, LEDs, and printed resistors enables cost reduction of up to 30% over conventional electronics.

In-Mold Electronics has 4 distinct process steps:

Step 1: Print Electronic Circuits

2D electronic circuit designs are screen printed onto plastic substrates with conductive inks such as silver and carbon materials, formulated for thermoforming as part of our In-Mold Electronics product range. Additional printing of electrically insulating dielectric cross-over inks allows further conductive layers to be printed, enabling more complex designs. Related stretchable conductive materials support designs requiring higher elongation.

Silver Die Sinter Attach Materials used for Power Management Device

Step 2: Component attach

Components are attached using specialist conductive adhesives that are dot-dispensed using pressure-time automated equipment or stencil printed. Components are placed using conventional surface mount technology (SMT) pick-and-place equipment. A structural adhesive may be used to increase bond strength.

Step 3: High Pressure or Vacuum Thermoform

The substrates with deposited electronic circuits are then processed using a thermoforming tool. The substrate is heated to the point where it starts to soften. At this stage, the substrate is deformed over the mold and then rapidly cooled thereby creating a 3D electronic circuit.

Step 4: Injection Molding and Trimming

The final stage is to over-mold the substrate, encapsulating the electronic circuitry with an injection molded resin. This encapsulation provides excellent long-term durability. The device is then cut to size by stamping or laser cutting. Component joints can be further protected before molding with encapsulant and underfill materials.

Dycotec's Current In-Mold Electronics Product Portfolio

Dycotec's In-Mold Electronics product category covers thermoformable conductive pastes, cross-over dielectrics, flexible conductive adhesives, and insulating encapsulants. The guidance below summarises the current catalogue.

For selection of conductive pastes, consideration of electrical conductivity versus thermoformability is required. DM-SIP-1005 has excellent thermoformability and proven high-volume printability with long screen residence times, with extensive and proven high durability performance.

For applications that need high electrical conductivity, silver conductive paste (DM-SIP-1006) with high electrical conductivity of 15 mΩ/□/25µm can be used where molded features do not have sharp gradients. Cross-over dielectric (DM-INS-1506) offers excellent breakdown voltage (>31 kV/mm), is cost effective with only 2 layers required to be printed to avoid shunt resistance, and has excellent printability.

Flexible conductive adhesives such as DM-SAS-10030 overcome stress-related failures observed with more rigid epoxy-based conductive adhesive systems and are compatible with plastic injection molding processes. This conductive adhesive is available in syringe packaging as well as in pots for use with stencil and screen printing. For screen printing, adhesive diluent should be purchased to reduce viscosity. Adhesion strength can be improved if our insulating flexible encapsulant, DM-UFL-16001, is used.

Our products have proven durability and are compatible with commonly used graphic ink layers. Due to the large number of applications that benefit from this technology, with varying thermoformed features, different graphic inks, molding conditions, and print processes, we work in partnership with our customers to ensure swift adoption (and customisation if needed) of our In-Mold Electronic inks into high-volume production.

Prototype Development and Scale-Up Support

We are able to demonstrate IME capability, building proof-of-concept demonstrators:

A range of industrial screen printers and IR, oven, and UV conveyors for manufacturing IME demonstrator parts.
SMT capability for automated assembly and 3-axis pressure-time dispense for electronically conductive and structural adhesive deposition.
3D printing and design capability with laboratory thermoforming tools.

These capabilities are delivered through our prototyping and development services, supported by design and modelling, durability testing, and custom formulations where a standard product is not an exact fit.

Please Get in touch to discuss your requirements, or explore the full In-Mold Electronics product range.