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The Printed Circuit Designer’s Guide to... DFM Essentials
by Anaya Vardya, American Standard Circuits / ASC Sunstone Circuits
Chapter 2: Panelization
Panelization is the process of placing one or more PCBs on a manufacturing panel and incorporating features to assist manufacturing (such as tooling holes, fiducials, coupons, panel thieving, etc.). Panelization is one of the highest impact factors in the cost of a PCB.
The panel area available for circuit boards plus coupons is known as the usable area (Figure 2.1). Test coupons are added by the fabricator to the perimeter of the manufacturing panel outside the usable area. The number and type of coupons are based on the specs that the PCBs are being built to and requirements for controlled impedance. Coupons may sometimes further reduce the amount of a PCB panel that is available for the circuit boards. This is defined by the fabricator as required perimeter for coupons. This is typically about 1 inch or 25.4 mm and is a fixed area based on panel size. Panel utilization is measured as a percentage, defined by the total area for PCBs divided by the total panel area.
Cost-effective material utilization is defined by a target panel with greater than 75% panel utilization. Raw laminate is one of the primary cost constituents of a multilayer PCB. Optimizing panel structures around standard base materials while achieving maximum material utilization on one of the standard panel sizes can have a significant impact on multilayer board prices and deliveries. The three most preferred sizes in North America are 12x18 inches, 18x24 inches and 21x24 inches, with 18x24 inches being the most common. For special applications, other panel sizes can be provided. In Asia, typically the shops will process custom panel sizes in order to maximize utilization. The most effective cost per unit area processed is usually found with a larger panel size.
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