The manufacturers nowadays are forced to respond very quickly to changes in the market conditions. To adopt flexible mixed model assembly lines (MMAL) is a preferred way for manufacturers to improve competitiveness. Managing a mixed model assembly line involves two problems: assigning assembly tasks to stations (balancing problem) and determining the sequence of products at each station (sequencing problem). In order to solve both balancing and sequencing problem in MMAL simultaneously, an integrated mathematical model based on mixed integer programming (MIP) is developed to describe the problem. In the model, general type precedence relations and task duplications are considered. Due to the NP-hardness of the balancing and sequencing problem of MMAL, GA is designed to search the optimal solution. The efficiency of the GA is demonstrated by a case study.

A mixed-model assembly line (MMAL) is a type of production system that is capable of producing different models of a common base product simultaneously. Mixed-model assembly line level scheduling problem (MMALSP) is a challenge for Just-in-time (JIT) production systems. In the paper, a mixed-model assembly line level scheduling model is proposed which considers multiple objectives simultaneously. The considered objectives include the variation in parts consumption considering the batch part supply, inventory cost and maximum transportation load. An approach based on genetic algorithm is proposed to solve the multiple objectives problem. In order to translate individuals in the GA population into candidate scheduling schemes a delivery scheduling algorithm (DSA) is proposed. In addition, dimensionless processing technique is employed in the design of the fitness function in order to comprehensively evaluate different individual considering three objectives simultaneously. The approach’s performance is validated through comprehensive experiment.

The deterministic ultraprecision machining achieves accuracy and repeatability not possible using conventional optical machining techniques, greatly enhances product quality, providing a quantum leap in throughput, productivity, yield, and cost effectiveness. The deterministic ultraprecision machining technology, involving various ultraprecision process from turning, flycutting, grinding and polishing to finishing, is usually referred to the following technologies such as single point diamond turning (SPDT), deterministic microgrinding (DMG), magneto-rheological finishing (MRF),computer controlled polishing (CCP), and computer controlled optical surfacing(CCOS),etc. This paper discusses mainly the current state and development trends of the deterministic ultraprecision machining technologies at home and abroad. In addition, the paper also elaborates on the technical features of the various deterministic machining technologies mentioned.

This paper presents a technique for processing Terahertz radar reflector by SPDT (Single Point Diamond Turning) based on LODTM (Large Optics Diamond Turning Machine). This technique applies single crystal diamond cutting tools for ultra-precision machining, and thus could obtain high-precision optical mirror, which could be used as the Terahertz radar reflectors. An experiment for aluminum sample had been done to demonstrate the availability of the technique, and a pair of Terahertz radar reflectors were obtained. The precision of the reflectors, detected through precision coordinate measuring technology, was better than the designed requirement. The experiment results showed that Terahertz radar reflectors generated by deterministic ultra-precision machining technique based on LODTM would have advantages in figure accuracy and roughness and so on, which could be helpful to improve the precision and low the cost of Terahertz radar system.

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