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Non‐woven glass epoxy laminates are compared with paper phenolic and woven glass epoxy, indicating the advantages and limitations of the newer materials. Certain electrical properties are compared together with thermal and dimensional stability performances. This paper was presented at the Institute of Metal Finishing Printed Circuit Group Symposium “Circuits 77” in London during March 1977.

Non‐woven laminates have begun to gain recognition in the electronics industry because they are generally thinner and flatter than woven laminates. This study characterizes the mechanical and thermo‐mechanical properties of non‐woven, randomly dispersed, short fiber laminates, and identifies potential failure mechanisms which must be addressed in the design and utilization of printed circuit boards using non‐woven technology.

Emerging ‘chip‐size’ packages, and bare flip‐chips, require new substrate properties if high lead count chips are to be reliably interconnected on printed wiring boards and multichip modules at low cost. Blind via holes have been shown to increase interconnect density significantly without adding layers which contribute to high cost. Until recently, the use of blind vias has been limited to high‐end applications since standard fabrication methods, either sequential lamination or controlled depth drilling, are too slow and expensive for most high volume commercial applications. To maintain a low layer count while interconnecting higher I/O packages, commercial and consumer electronics require a substrate technology which supports high speed, micro‐via hole formation. This paper describes a process for fabricating high speed micro‐vias in dimensionally stable non‐woven Aramid reinforced laminates using laser ablation technology. Laser equipment capable of producing over 100 blind micro‐via holes per second is discussed. The process steps of hole cleaning and plating are reviewed, showing how existing PWB manufacturing technologies can be used. This process is compared with other methods of generating small holes and blind vias in printed wiring boards. In addition, requirements for flip‐chip and chip‐size packages, including a coefficient of thermal expansion of <10 ppm/°C and thin laminate dimensional stability of <0.03%, are explained.

Permittivity and dissipation factor (D_k and D_f) are effects of polarization of different components of the dielectric substrate material when subjected to an electrical field. A database of these important design parameters for PWBs has been developed for Thermount RT. Effects of variations in the level of moisture (bone‐dry to completely saturated at various relative humidity levels), testing temperature (room temperature to 120uC) and testing frequencies (1MHz to 1.5GHz) on D_k and D_f are reported. As the frequency of test is increased from 1MHz to 1.5GHz, the effect of moisture on the properties is reduced. Comparison with conventional glass/FR4 laminate properties shows the distinct advantage of Thermount. It is increasingly used in high frequency cellular telephone, satellite, and wireless applications which require HDI PWBs to achieve the highest packaging density at the lowest cost and weight.

More and more disposable goods are available in surgical rooms. Rules and standards have been proposed in order to prevent infection from patient to surgical team and vice versa. A proposed mandatory European standard prEn 13795 “Surgical drapes, gowns and clear air suits used as medical devices, for patients, clinical staff and equipment”, is being developed by the Committee of European Normalisation and specifies the basic performance requirements and test methods for single‐use and reusable materials after sterilisation process. Therefore, the performances of the surgical gowns demand a balance between barrier and comfort properties. In comfort evaluation, tactile feeling is one of the most primary and important aspects with regard to the grading of the products. Therefore, the influence of the sterilisation process on the tactile perception is important to be evaluated. Subsequently, the final aim of this paper is to contribute to the knowledge of influence of sterilisation treatment on the tactile perception.

Trace Instruments have announced that Mr Tony Battaglia has been named central regional sales manager.

Prostab International Ltd, the military and scientific video manufacturing company, has recently announced the release of the Promatic 4800 Portable Video Cassette Recorder. This monochrome video recorder has a 5.5MHz bandwidth for high resolution recording.

This paper focuses on some of the presentations given at a technical workshop on “Laser processing of polymer‐based materials”, organised by Association of Industrial Laser Users. Applications in cutting and welding are discussed and specifically how different combinations of polymer materials and laser types produce different results. Applications are described that include pre‐weakening of car trims for integrated airbags and “on the fly” scribing of web materials used in packaging. In several of these applications, robots play an important role in manipulating the laser beam.

Investigates the potential for building smart seams by incorporating optic fibers ultrasonically. The heating and bonding mechanisms of ultrasonic welding process in fabrics were studied. Battle dress uniform (BDU) (50/50 nylon/cotton), 100 percent cotton, 100 percent polyester and Nomex fabrics were used and were bonded ultrasonically with and without polyurethane adhesives. The effects of three important welding parameters, namely weld pressure, weld time and amplitude of vibration, on the joint strength and the temperature profile at the interface were examined. The temperature profiles for different fabrics were measured during ultrasonic welding process. The attenuation degree of signal transition properties of optic fibers incorporated was tested to determine if ultrasonic process provided a possible way of embedding optic fibers into seams and achieving sufficient joint strength while the signal transmission properties of optic fibers incorporated were not changed significantly.