BANNOCKBURN, IL -- North American PWB shipments rose 7.7% year-over-year in September but orders plunged 12.9%. The book-to-bill ratio was 1.00, down from 1.06 in August, according to IPC's monthly survey of board fabricators. 

Sequentially, shipments rose 7.1% and bookings dropped 6.6%. Year to date, shipments are up 9.9% and bookings are up 8.8%.

The rigid PWB book-to-bill fell to 1.01, while the flex circuit ratio dropped to 0.92. The ratios are calculated by dividing the value of orders booked over the past three months by the value of sales billed during the same period from the companies in IPC’s survey sample.  A ratio of more than 1.00 suggests future expansion.

For the month, rigid board shipments rose 6.6% but bookings dropped 14.4% versus last year. Flex circuit shipments rose 24.3% and bookings were up 14.7%.

There are questions as to how representative the data are of the industry. According to IPC, at least 17% of the shipments were not domestically produced. Furthermore, about 31% of the flex circuit value came from assembly and other services. Also, several major board fabricators reportedly do not participate in the survey.