Component carrier replaces flexible printed circuit boards

Flexible printed circuit boards have many advantages. However, assembly and mounting are quite complex. Based on 3D-MID technology, Harting has developed a new solution that can replace flex PCBs. Up to two thirds of the costs can be saved by using a component carrier.

Flexible printed circuit boards made of thin polyimide films have become established in many product areas due to their flexible application possibilities. However, their assembly and mounting requires increased handling effort. This is where a newly developed component carrier comes in.

Standardized carrier for electronic components

The component carrier developed by Harting can be fitted directly with electronic components and thus replace flexible printed circuit boards. The carrier serves as a connecting element between the printed circuit board (PCB) and components such as LEDs, ICs, photodiodes or sensors.

The assembled component carriers are supplied in blister tapes on reels (tape & reel) and can be processed as a standard design, like other SMDs, by automatic assembly. Two different sizes are currently available, on which electronic components with the standard size SOIC-8 and smaller can be assembled. In addition, the supplier also realizes customer-specific sizes.

Here are three examples of applications where the component carrier can replace flex PCBs:

• Components at a 90° angle to the PCB: The component carrier is suitable when electrical components such as sensors are to be positioned at right angles to the PCB. The automatic placement process enables high accuracy in the positioning of temperature and Hall sensors, which leads to precise, repeatable measurement results. Another application example is optical components such as LEDs or photodiodes for the realization of precise light barriers.
• Distance to the circuit board: The component carrier also enables a distance between the circuit board and an electronic component. A temperature sensor can therefore be used for temperature measurement in the housing without the measurement result being influenced by the waste heat from other components on the PCB. In this way, an LED can be placed at a distance from the PCB, thus avoiding possible shading of surrounding components.
• Antenna function: The component carrier can be manufactured with different base polymers. Electrical properties such as dielectric constant and dissipation factor of the materials suitable for antennas can be taken into account. The application-specific antenna layout can be used for various applications in the MHz and GHz frequency range, such as Bluetooth, WiFi, ZigBee or 5G.

3D-MID technology as an alternative to flex PCBs

3D-MID technology (Mechatronic Integrated Device) allows electronic components to be fitted directly onto a three-dimensional base body without the need for PCBs and connecting cables. The base body is produced by injection molding, whereby the thermoplastic material is provided with a non-conductive, inorganic additive. The additives in the plastic are 'activated' by laser direct structuring (LDS) so that this material can accommodate electrical conductors. Theei laser beam describes the surfaces intended for the conductive paths and a microrough structure is created. The released metal particles form the cores for the subsequent chemical metallization.
In this way, electrical conductors are applied to the three-dimensional base body. The plastic used has a high heat resistance and can therefore be soldered in the reflow oven.

Harting has been implementing the entire 3D-MID process chain in-house for over 10 years, from the project idea to the assembled series product. The technology is used for applications ranging from medical technology, industrial and consumer electronics to safety-relevant components in the automotive industry.

The component carrier developed using this process can be used flexibly for different applications. For example, it can be fitted with several sensors that are aligned in three directions for measurement in three axes (X, Y, Z). The components can be applied simultaneously to two parallel surfaces on the front and rear as well as on the front surface. Harting has applied for a patent for the component carrier.

Component carrier saves two thirds of the costs

Electronic components such as LEDs, ICs, photodiodes and sensors are automatically mounted directly onto the component carrier. The total costs for the component carrier are two thirds lower compared to flex PCB solutions. The cost advantage results from the elimination of the often complex handling of flexible PCBs, such as assembly, gluing and mounting. The process is advantageous even for small quantities, as the component carrier can be used unchanged for different applications and there are no costs for a new injection molding tool. Compared to flex PCBs, more precise positioning of the components and greater repeat accuracy are also achieved.

The supplier cites the short project time to delivery of finished components as a further advantage of the component carrier. As the plastic carrier remains unchanged, specifications for the positioning of the electronic components are sufficient. The 3D-MID experts use these to create a production-optimized layout proposal. Adjusting the laser program is sufficient to adapt the electrical conductor paths to the respective application. Delivery of the first samples from production is possible within two to three weeks after approval by the customer and delivery of the components - even faster if necessary.