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Based on the superior properties of the COPNA resin laminate exhibiting Tg at 255∞C, small CTE at 5‐7 ppm (xy‐axis) and at 29 ppm (z‐axis), reliability of both two‐layered and six‐layered printed wiring boards using COPNA resin as a matrix were evaluated. In the case of the two‐layered system, it exhibited higher reliability than the FR‐4 graded epoxy‐resin laminate in the entire tests, and exhibited higher reliability than the BT resin laminate in the THB test, heat‐shock test, and heat‐cycle test. In the case of the six‐layered system, it also exhibited higher reliability than the BT system in both heat‐shock test and PC test.

In this second part of the report on Printed Circuit World Convention IV held at the Tokyo Prince Hotel, Tokyo, from 3–5 June 1987, a general synopsis of the content of the papers presented in the eighteen technical sessions will be given. As three sessions were run in parallel throughout the 2½‐day conference, and therefore not all presentations were heard by those reporting on the technical programme, a number of them have been briefly summarised from the Convention Proceedings.

Recycling technology for printed wiring boards (PWBs) with mounted electronic components was studied for the purpose of disassembling the boards, recovering useful materials, and reusing these materials. An automatic removal method was developed for the electronic components on the basis of a combination of heating to above the solder melting temperature and applying impacting the shearing forces. Most of the electronic components were recovered undamaged and the solder was able to be recovered as particles. The solder remaining on the board was recovered by abrading the board surface and by using a heating‐impacting process. After these processes, the resin board (a cured epoxy resin board reinforced with glass fibre)was pulverised and separated into a copper‐rich powder (copper: 82 Wt%) and a glass fibre and resin mixture powder (glass fibre‐resin powder) by gravimetric and electrostatic methods. The recovered electronic components, solder and copper‐rich powder were used as valuable metal resources for refining. Moreover, the recovered glass fibre‐resin powder was found to be a useful filler for plastic products such as epoxy resin and ABS (acrylonitrile/butadiene/styrene copolymer) resin.

Rigid multilayer polyimide printed wiring boards exhibit unusually large dimensional change during the lamination process. Therefore, the use of large polyimide multilayer panels for high density circuitry is often limited. This study examined ten probable causes for dimensional instability and how each affected the shrinkage/growth in the laminated panel. The report shows that a combination of methods and materials can reduce the resultant dimensional change experienced during lamination from 0·001 inch/inch to less than 0·0002 inch/inch in planar directions.

The Japanese PCB industry is in many ways comparable with the industry in the UK and yet is achieving higher levels of output and taking a somewhat different route in technology. This paper examines the structure of the industry in terms of company size and number, looks at the level and nature of investment and goes on to examine technologies being used and results being achieved.

The Printed Circuit World Convention 1993 was held at the Fairmont Hotel, San Francisco, from 11–14 May 1993. The Convention was the sixth in the series held at three‐year intervals and represents the major conference on all matters relating to processing, development, management and future predictions within the industry. Over 60 papers in three concurrent sessions were held over the conference period.