Samuel LeBlanc, Paul Deffenbaugh, Jacob Denkins, Kenneth Church
Printed electronics is a familiar term that is taking on more meaning as the technology matures. Flexible electronics is sometimes referred to as a subset of this and the printing approach is one of the enabling factors for roll to roll processes. Printed electronics is improving in performance and has many applications that compete directly with printed circuit boards. The advantage of roll to roll is the speed of manufacturing, the large areas possible, and a reduction in costs. As this technology continues to mature, it is also merging with the high profile 3D printing. 3D printing is becoming more than just a rapid prototyping tool and more than just printing small plastic toys.
Companies are embracing 3D printing as a manufacturing approach to fabricate complex parts that cannot be done using traditional manufacturing techniques. The combination of 3D printing and printed electronics has the potential to make novel products and more specifically making objects electrically functional. Electrically functional objects have the advantage of competing with printed circuit boards. Printed circuit structures will be a new approach to electronic packaging. It is the desire of many companies to reduce assembly processes, decrease the size of the electronics, and do this at a reduced cost.
This is challenging, but the potential of printing the structure and the electronics as a single monolithic unit has many advantages. This will reduce the human touch in assembly, as the electronics and the object are printed. This will increase the ruggedness of the product, as it is a monolithic device. This will eliminate wires, solder, and connectors, making the device smaller. This has the potential to be the future of printed circuit boards and microelectronic packaging. This paper will show working demonstrations of printed circuit structures, the obstacles, and the potential future of 3D printed electronics.
PCBs today are optimized and ubiquitous. They can be mass produced, created relatively quickly, and are a proven, reliable product. They do have their limitations, though. They are process intensive, one-offs are not necessarily economical, and they produce a lot of waste, which creates extra expense to manufacture in the U.S. Printed circuit structures are the evolution of the PCB and 3D printing industries. They have several distinct advantages over PCB in that they greatly reduce process steps, one-offs and customization are easy because of the DDM process, and since they are primarily additive, there is very little waste. However, there are still some obstacles present. PCS as it is today would struggle with large volumes because the speeds are not yet there. Strength of fabricated parts is another obstacle in the way of PCS.
3D printed parts are not as strong as bulk properties, so consideration must be taken into the design of the PCS. Using the methods described in this paper, these two issues were addressed and improvements have been made. A more than 2x speed increase was realized through the use of "Spaghetti" printing which also yielded a stronger, smoother part. Another method of increasing strength utilized a laser to reflow already printed plastic creating better line-by-line and layer adhesion. Combining these methods, stronger, more durable printed circuit structures can be fabricated much faster.