Results 1 - 10 of 958
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[en] A software package for the automatic layout of printed circuit boards is presented. The program permits an interaction of the user during the layout process. The automatic searching of paths can be interrupted at any step and convenient corrections can be inserted. This procedure improves strongly the performance of the program as far as the number of unresolved connections is concerned
[en] Efforts were undertaken to study and select fabrication methods suitable for processing multiple hybrid microcircuits (HMCs) on 3.75- by 4.5-in. (95 by 114 mm) substrates through thin-film metallization and photolithography. Each fabrication method studied was based on its potential for multiple hybrid microcircuit processing. Thin-film deposition parameters were analyzed in terms of thin-film properties necessary to meet HMC electrical and component attachment requirements, and photolithography parameters were analyzed in terms of dimensional requirements on the circuit pattern. The objective of this effort was met, and the techniques developed are being used successfully in the production of multiple HMCs
[en] Microstrip copper lines play an important role in high-speed printed circuit boards. It is necessary to perform appropriate surface finishing on the microstrip copper lines to avoid oxidation and reduce the loss of signal transmission. In this work, the microstrip copper lines after micro etching treatment were finished with immersion silver, immersion tin and electroless nickel immersion gold (ENIG), respectively. Surface microstructures, 3D features and surface contact angle were examined to find the effect of the copper finishing on signal transmission loss. The results indicated that the microstrip copper lines with micro-etching treatment exhibits low signal transmission loss as − 39.9 dB/m at 20 GHz. The tested microstrip copper lines showed that signal transmission loss follows an increasing trend successively with micro etching treatment, immersion silver treatment, immersion tin treatment and ENIG treatment.
[en] The article deals with the problem of minimizing the number of setups for mounting SMT machines. SMT is a device used to assemble components on printed circuit boards (PCB) during the manufacturing of electronics. Each type of PCB has a different set of components, which are obligatory. Components are placed in the SMT tray. The problem consists in the fact that the total number of components used for all products is greater than the size of the tray. Therefore, every change of manufactured product requires a complete change of components in the tray (i.e., a setup change). Currently, the number of setups corresponds to the number of printed circuit board type. Any production change affects the change of setup and stops production on one shift. Many components occur in more products therefore the question arose as to how to deploy the products into groups so as to minimize the number of setups. This would result in a huge increase in efficiency of production
[en] The macro-to-micro interface method presented here meets many of the requirements for an ideal interconnect by sealing a short length of plastic tubing directly to a microfluidic chip. The adaptability and low-temperature processing make it compatible with a wide range of device materials. The method was validated on silicon, acrylic (polymethyl methacrylate), printed circuit board and glass substrates with high-pressure integrity to over 300 psi (2 MPa). Fluid interfaces created with this method were used for pressure tests on microfluidic channels constructed on silicon. (technical note)
[en] We have developed a vacuum chamber and control system for rapid testing of microfabricated surface ion traps. Our system is modular in design and is based on an in-vacuum printed circuit board with integrated filters. We have used this system to successfully trap and cool barium ions and have achieved ion ‘dark' lifetimes of 31.6 s ± 3.4 s with controlled shuttling of ions. We provide a detailed description of the ion trap system including the in-vacuum materials used, control electronics and neutral atom source. We discuss the challenges presented in achieving a system which can work reliably over two years of operations in which the trap under test was changed at least 10 times
[en] A literature search was conducted to support development of in-house diagnostic testing of thick film materials for hybrid microcircuits. A background literature review covered thick film formulation, processing, structure, and performance. Important material properties and tests were identified and several test procedures were obtained. Several tests were selected for thick film diagnosis at Bendix Kansas City. 126 references
[en] A system employing an array of inductive pick-up coils around the perimeter of a cylinder has been developed for measurements of the rapidly changing field in the new corrector magnets for the Fermilab Booster. The coils are fabricated on printed circuit boards and feature windings which buck dipole, quadrupole, and sextupole fields, allowing sensitive measurements of both strength and higher-order harmonics. The array of coils is simultaneously sampled at data rates of up to 100kHz with 10kHz bandwidth using 24-bit ADC's
[en] Assessment of thermal phenomena in the drilling of laminates is critical in printed-circuit production. A quasi-determinate model permits calculation of the expected temperature in the cutting zone during the drilling of small mounting sockets and pass-through holes, with consequent decrease in manufacturing waste.