Metal Core PCB Challenges

Below are some of the critical challenges that a fabricator will face when manufacturing metal core PCBs. These are the most consistently documented issues over years of experience affecting the ability to efficiently and cost effectively produce metal core pcb.

Plated Through Holes

One of the biggest challenges when manufacturing metals core PCBs (or any printed circuit boards really) is making sure you can prepare the hole wall properly, removing all the debris from drilling to assure that a reliable hole wall call be deposited.

For exampleyou have Teflon from the Rogers material, resin from the FR-4, and copper fragments from the copper all stuck to the hole wall after drilling. Traditional de-smear techniques and processes will not work here, which is why it is critical to use Plasma Desmear for these types of boards and to have a coupon on the production panel which can be cross sectioned to ensure hole wall cleanliness prior to electroless copper (which is the only metal deposition technique that will work here) as there is no turning back from that step.

Assuring That the Thermal Expansion Properties of the Materials Are Similar

As discussed above, it is critical to understand the operating CTE temperatures for reliable operation of metal core PCBs. For the manufacturer, it is just as important to understand the CTE parameters when developing processes like lamination cycles and HASL. Many times, we will strategically place thieving into our production panels to draw heat away from the production parts.

Extremely Tight Tolerances

Traditional PCB tolerances of +/- 0.005” or +/- 10% for many of the mechanical and electrical properties don’t always apply to MCPCB. When trying to attach a high speed to a metal core PCB to do two functions in one, we get into very tight electrical tolerances that can be down to +/- 0.001”. With those tight tolerances, many of the mechanical dimensions require precision CNC machining when it comes to routing to and through metal cores.