BANNOCKBURN, Ill. — Flex circuits recorded a May book-to-bill of 1.32, while rigid PCBs hit 0.98. The total PCB industry hovered at 1.01, according to IPC — Association Connecting Electronics Industries' monthly North American PCB statistical program. Overall PCB sales in 2007 are averaging about 10% below 2006 sales thus far, noted Denny McGuirk, IPC president.

Combined, PCB industry shipments slowed by 14.5%, and bookings dropped by 11.2%, year-to-year. Rigid PCBs, 88% of the PCB market, saw shipments from North America-based producers drop 14.8% and bookings fall 12.2% from May 2006. Flexible circuits recorded a 10.1% decline in billings and a 2.9% in bookings over the same month last year.

Year-to-date, combined flex and rigid PCB figures indicate a 10.3% decline in shipments and 15.6% drop in bookings. Rigid PCB shipments fell 10.9% and bookings declined 17.7%. Flex circuit shipments rose 0.7% and bookings were up 23.8%, indicating a growth in demand paired with relatively flat shipping volumes, noted McGuirk.

Compared to April, the book-to-bill ticked upward slightly from 1.00 to 1.01, indicating continued market stability, which will remain below 2006 revenues for several months, predicts McGuirk. Overall, North America-based PCB manufacturers saw shipments rise 7.2% and bookings grow by 1.9%. Rigid PCB shipments climbed 6.7% over April, and bookings increased by 2.1%. Flex circuit shipments improved by 15.7%, though bookings fell 0.4%.

Participating survey companies reported 89% of PCBs produced were manufactured domestically. Rigid PCB manufacturers indicate 89% is domestic production; Ninety-six percent of flex circuits are manufactured in North America. Flex circuit manufacturers noted that bare circuits accounted for 80% of shipment value in May, with the remainder accounting for value-add services.

Book-to-bill ratios are calculated by dividing orders booked values by the value of sales billed, each over a three-month period. A ratio of more than 1.00 indicates probable near-term growth. Percentages for indicators such as domestic production and value-add services are heavily affected by the sample mix in IPC's survey.