A Research On The Man-hour Quota Of Ship Hull Plate Cold Process

Man-hour quota is the fundamental unit of the theoretical cost calculation. It is not only the basis of work performance evaluation, cost calculation and price estimation, but also the important principle of making the reasonable production plan, establishing standard time limit for a project and arranging the human resources. Furthermore, it is considered by the manufacturing company as an important tool to strengthen its competition in the market through achieving scientific modern management and improving its productivity. As the traditional manufacturing company, shipbuilding enterprises'management is poor, especially in the aspect of man hours of ship hull plate cold processing, which affects the establishment of production plan and the improvement of production efficiency and limits the enterprises'development. At present, shipbuilding enterprises generally use look-up tables and experiences to estimate the plate cold processing time. However, this kind of approaches requires that related charged person should have abundant experiences. The man hours also change as the transformation of production conditions, such as machine, work environment and so on. Therefore, man hours estimated by these methods would lead to large deviation from practical time.In order to estimate the plate cold processing man hours accurately, plate cold processing can be classified into plate roll bending process and plate pressing process. Different methods are then used to estimate the man hours for two plate cold processes separately. In order to calculate the man hours conveniently, man-hour management system based on previous methods and developed models has been designed and realized. Details of main research contents are as follows:1. Study on the time quota estimation methods and models for plate roll bending process. According to plate roll bending process, in order to deduce the function of top roll position, elastic-plastic deformation and the final status of the plate are analyzed. Based on the top roll movement times and the time of each movement, elastic-plastic theory based time calculation function is established. At last, the models are used in practical situations to estimate the time. The results of the models are compared with the actual time to demonstrate acceptable performances of the developed models. 2. Study on the time quota estimation methods and models for plate pressing process. According to the process, multiple linear regression model and neural network model are established to estimate the time of plate pressing process. Through comparisons of the two models'results, the neural network model is chosen to estimate the plate pressing process time. At last, the model is evaluated through the comparison with the actual time.3. Study on design and development of man-hour management system. The systems is based on Windows7 operation system of Microsoft Corporation and the development tools are the software of Visual C#2008, SQL2008 and Matlab. For plate roll bending process, the software of Visual C# and SQL2008 are used to develop the function of managing model parameters and calculating roll bending process time. For plate press process, the software of Visual C#2008, SQL2008 and Matlab are used to develop the function of pre-processing the data, training neural network, managing model parameters and calculating plate pressing process time. At last, the system is applied in practice to estimate the actual man hours.