Laser drilling improving circuit board manufacturing

We reported here a novel technique for laser high speed drillings on Printed Circuit Boards (PCBs). A CNC solid laser based system is developed to drill through and blind vias as an alternative to mechanical drilling. The system employs an Acousto-Optic Q-switched Nd: YAG laser, a computer control system and an X-Y moving table which can handle up to 400 x 400 mm PCB. With a special designed cavity the laser system works in a pulsed operation in order to generate pulses with width down to 0.5 mu s and maximum peak power over 10kW at 10k repetition rate. Delivered by an improved optical beam transforming system, the focused laser beam can drill hobs including blind vias on PCBs with diameter in the range of 0.1 - 0.4 mm and at up to 300 - 500 vias per second (depending on the construction of PCBs). By means of a CNC X-Y moving system, laser pulses with pulse-to-pulse superior repeatability can be fired at desired location on a PCBs with high accuracy. This alternative technology for drilling through or blind vias on PCBs or PWBs (printed wiring boards) will obviously enhance the capability to printed boards manufacturing.

Gasdynamic Heating Process Suitable for Manufacturing Ethene by Pyrolysis

对乙烷裂解制造乙烯的非平衡过程进行了分析,为了获得高的乙烯产率,需准确控制裂解停留时间并提高裂解反应温度,探讨了目前工业生产中普遍采用的管式裂解炉的特性及局限,这种管式裂解炉的性能虽己接近完善,但仍不能满足裂解工艺需求,对几种利用激波控制加热方法生产乙烯的发明及其不足进行了评述,提出新颖的反向超声速射流混合加热方法,该方法能满足裂解制造乙烯的要求。

Modeling and optimization of semiconductor manufacturing process with neural networks

A neural network-based process model is proposed to optimize the semiconductor manufacturing process. Being different from some works in several research groups which developed neural network-based models to predict process quality with a set of process variables of only single manufacturing step, we applied this model to wafer fabrication parameters control and wafer lot yield optimization. The original data are collected from a wafer fabrication line, including technological parameters and wafer test results. The wafer lot yield is taken as the optimization target. Learning from historical technological records and wafer test results, the model can predict the wafer yield. To eliminate the "bad" or noisy samples from the sample set, an experimental method was used to determine the number of hidden units so that both good learning ability and prediction capability can be obtained.

Microspheres and microcapsules, a survey of manufacturing techniques: Part III: Solvent evaporation

A methodological survey of microsphere formation and microencapsulation techniques based on solvent extraction/evaporation techniques is presented. Thus, basic features of solvent extraction and solvent evaporation processes, including droplet formation, droplet/particle stabilization, and solvent removal, are outlined. Preparation of a wide range of microspherical and microcapsular products based on biodegradable polyesters, polysaccharides, and nonbiodegradable polymers are discussed. Dependence of microcapsule characteristics on manufacturing parameters, as well as performance evaluation of microspherical and microcapsular products, are also briefly covered.

A Scheduling Algorithm for Flexible Manufacturing Cell

In this paper, a new scheduling algorithm for the flexible manufacturing cell is presented, which is a discrete time control method with fixed length control period combining with event interruption. At the flow control level we determine simultaneously the production mix and the proportion of parts to be processed through each route. The simulation results for a hypothetical manufacturing cell are presented.

国有企业管理者裁员决策特征及其对留岗者心理影响的研究

In China, orgnizational change and downsizing are the primary topics studied in I/O psychology and Human Resource Management. Due to the great need in reality, both theorists and practitioners raised the same questions: Does downsizing increase the organizational performance? What is the relationship between organizational downsizing strategies and survivors' psychological reations? Which factors influence managers' downsizing decision-making most? How can managers manage the process successfully? The purpose of this study is trying to answer these questions, and then to establish the downsizing decision-making model of China's SOE (State owned enterprise) managers. The hypothetical model of SOE managers' downsizing decision-making was put forward, based on a tremendous amount of literature on downsizing decision-making, especially on the downsizing decision-making model built by B. Shaw, and also based on the results of the interviews conducted to the SOE managers who have the downsizing decision-making experiences. In order to test and verify the model, 322 SOE managers were investigated by a questionnaire study. And the statistic results supported the hypothetical downsizing decision-making model. Further, 259 survivors (those who are still working in the SOEs) from 7 downsized SOEs and 1 non-downsizing SOE, were also investigated by a questionnaire study. The statistic results also supported the hypothetical downsizing decision-making model. A subsequent case study was performed upon one downsized SOE; and a deliberate focus group interview study within 6 SOE mangers from another downsized SOE was also conducted. Both fundings from the two studies surported the hypothetical model again. Thus, China's SOE managers' downsizing decision-making model was established. This China's SOE managers' downsizing decision-making model suggests the following: Firstly, the characteristics of managers'downsizing decision-making were the center of the model. Those characteristics displayed during the process of the downsizing decision planning, the participation of downsizing decision-making and the communication concerning downsizing events, were influenced by managers' sense of crisis, controlling factors out of the organization and the managing experience within it. Especially, the latter two factors were more important. Secondly, in downsizing decision-making problems, the perceived crisis of China's SOE managers was mainly influenced by the outer factors, esp. the controlling factors from the government or the high authorities, but not by the inner factors including manufacturing management, HRM skills and organizational competition strategies. Thirdly, survivors'psychological reactions (including job satisfaction, job motivation, team working cooperation, etc) were mainly influenced by the characteristics of the managers' downsizing decision-making, at the same time, also by the outer factors (including controlling and social security factors) and the inner factors (including competition strategy and HRM skills). Finally, according to the model and the results from this study, the conclusions were reached in the followings: The stronger the controlling effort upon the SOE managers, the worse the effect displayed during the downsizing process. And in order to improve the effect and quality of downsizing decision-making, SOE managers need a lot of training to ameliorate their competencies such as competition strategies and HRM skills.