More and more high-volume electronic manufacturing has been continuously transferred to low-cost countries. Western countries are seeking new technologies to establish a firm foothold in low-yield, high-profit production.
Digital printing of conductive materials is a flexible method of producing flexible and rigid PCBs without the need to provide expensive processing programs in advance. Non-repetitive processing greatly reduces the low production cost and turnaround time, and provides a way to replace the more labor-intensive processes that have traditionally been used for PCB production.
Traditionally, PCB production is a labor-intensive process with many steps, and each step requires some manual intervention. Traditional PCB production also relies on the initial costs of front-end non-repetitive engineering (NRE). It is usually embodied in the form of a production tool such as a photomask or a screen. This shows that the initial processing costs will have a serious impact on small-batch production operations, and the associated labor and infrastructure costs will determine the mass production costs. As a result, high-volume PCB production has to be transferred to low-cost countries to reduce costs.
Small-scale production operations often require the convenience of the production site to keep it relatively local. However, the processing and labor costs still indicate that this is an expensive process, and its low-cost unit parts cost is relatively high. Digital printing of conductive materials offers possibilities for non-labor-intensive production processes that also reduce costs by eliminating the need for initial processing tools such as screens or photomasks.
Digital deposition of conductive material
In the past decade, the feasibility of digitally printing conductive materials has caused great concern. The vast majority of this research stems from the field of organic electronics, where the premise of producing fully printed electronic devices and displays requires printable contact wires and signal buses. Most of the initial studies focused on conductive polymers such as polydiethoxythiophene/poly-p-phenylene sulphonic acid (PEDOT:PSS), and later solutions used carbon and metal particulate materials.
Conductive polymers have a relatively low conductivity problem, while thicker screen-printed silver materials can produce higher conductivities, but these materials must undergo a high-temperature sintering stage to obtain optimal conductivity, which limits the base material. The range of choices. However, the use of metallic inks generally does not allow ink jet printing of printed circuit boards (PWBs) because the particle size and direction of condensation can seriously affect the reliability of the printing process. New developments in the development of metal nanoparticles in inks have made inkjet printing possible, but the resulting thin ink layers and sintering requirements still limit the practicality of the process.
A low-temperature digital process that provides great conductivity will provide a fast and flexible way to complete rapid prototyping and low-to-medium volume production on low-cost flexible and rigid substrates.