PCB Production Improvements for a Greener Future
Raising the bar on motor technology also means making something that’s better for the planet.
At Infinitum, we’ve replaced the iron core and copper windings found in conventional motors with a unique printed circuit board (PCB) stator. By etching copper coils directly onto the PCB stator, we reduce overall copper use by two-thirds.
The slim profile of the PCB stator reduces the volume of the motor and the material needed to produce the housing, resulting in a motor package that is half the size and weight of conventional motors. Infinitum motors also include an integrated variable frequency drive (VFD) to provide precise control of speed and torque.
Placement of the PCB Stator
In an axial flux motor like Infinitum’s, magnetic flux travels parallel to the motor shaft (i.e., in the axial direction) rather than traveling perpendicular to the motor shaft, as expected in a radial flux motor. Infinium motors orient the stator parallel to rotor discs, and the stator is sandwiched between the rotors, as seen in Figure 1. As current passes through the copper wire embedded in the PCB stator, it generates an electromagnetic field that interacts with the magnetic fields surrounding the rotor magnets to generate torque and rotation.
These PCB stators are built using well established manufacturing processes. Since the early 1980s, a growing number of environmental restrictions and regulations have set out to minimize the environmental impact of PCB manufacturing, and we’re pleased to see a growing number of our industry partners taking steps towards greener fabrication.
Greening Up PCB Manufacturing
The PCB stator manufacturing process parallels the traditional PCB manufacturing process. A layout is printed on copper clad laminates, and the etching process removes excess copper to reveal traces and pads. The PCB layer stack is formed by laminating the board materials at high temperatures. Then, holes are drilled for mounting, and pin holes and vias are plated before coating with a solder mask or other finish. From there, the PCB moves on to reliability and performance testing.
Traditional methods of PCB manufacturing rely on energy-intensive processes with high emissions. These processes involve copper, resins, glass fiber, and a lot of water. To make matters worse, at the end of their usable life, most PCBs become waste products; especially when improperly handled, waste removal processes can exacerbate environmental impact. For example, retrieving copper and other metals from PCBs through incineration releases toxic gasses, and using acid to remove metals results in acidified wastewater.
Today, national and international regulations put pressure on PCB manufacturers to do better. Many manufacturers are beginning to use renewable energy sources in their PCB production facilities, wherever feasible.
Since the establishment of the U.S. Clean Air and Clean Water Acts (CAA/CWA), the Resource Conservation and Recovery Act (RCRA), and the U.S. Environmental Protection Agency, PCB manufacturing processes, materials, and waste treatment methods have evolved continuously.
Regulations have replaced:
- Solvent development and cleaning chemistries
- High volatile organic compound (VOC) emission chemistries and inks
- Lead in plating resists and laminate materials
- Ozone depleting ingredients
Many PCB manufacturing facilities have implemented zero-discharge systems that treat rinses to prepare them for reuse or repurpose, avoiding chemical discharge. They’re also making an effort to reclaim copper etching, minimize carbon dioxide emissions, improve panel utilization, see Figure 2, and recycle precious metals once a PCB reaches end of life.
In addition, Infinitum is making a pledge to reuse PCB stators in remanufactured motors. In testing of our PCB stators, we’ve found that this technology is highly durable. Rather than allow our stators, and other motor components, to end up in landfills, we’re committed to finding ways to reuse them to produce remanufactured motors for the next generation (and the next).
As science continues to advance, the EPA and other regulatory bodies will continue to refine their requirements for manufacturers, and with more interest and economic incentive associated with green PCB manufacturing, best practices will continue to proliferate.
We are staying focused on our environmental impact every step of the way. For more information about Infinitum and our approach to sustainability, contact us.