Study On Production Scheduling Of Aviation Composite Parts

The manufacturing process of aviation composite parts is complex and very special.The production cycle of a single part is long,the part is highly dependent on tooling.Different process sections of parts are in a semi-continuous state and coordinate with each other very difficult.At present,the production scheduling mode of enterprises is single and poor in timeliness.The production workshop often suffers from job waiting and work-in-progress retention,which affects the delivery of parts.Combined with the characteristics of multiple varieties,small batches,and long production cycle spans in the production process of composite materials,this thesis studies the production scheduling of aviation composite parts concentrating on the bottleneck process of hot-press forming and the key process of layup operation,and according to the constraints on front and back connection of each section in the whole production process based on production factors such as equipment,work station and personnel.The main research contents are as follows:(1)The production mode of semi-continuous operation of aviation composite parts is analyzed.The characteristics of production scheduling and two core sections of layup and hot pressing of aviation composite parts are highlighted.This thesis proposes a bi-level scheduling optimization with the hot press section as the core and adopting the pull production method to reverse the staffing ratio and the selection of parts working position under the condition that the utilization of the autoclave is maximized mode.(2)Aiming at the bottleneck process of hot-press forming,the scheduling optimization of cans in the hot-press forming process is converted into a twodimensional rectangular packing of the bracket.A mathematical model is constructed with the total number of supports as the minimum.The concept of residual space is introduced into the two-dimensional rectangular packing problem.Residual-spacemaximized algorithm is proposed.At the same time,considering the collaborative work of multiple employees in the clean room,builds a layup operation scheduling model with the goal of the smallest difference between the maximum completion time of the layup operation and the hot pressing time,and then determines the functional relationship between the individual parts and the number of workers.Based on the genetic algorithm framework,the coding,inheritance and other solving rules are designed.(3)Taking the production scheduling problem of aviation composite parts of company J as an example,combining the technological characteristics of the layup and hot pressing process,taking the optimization model of the tank discharge in the hot pressing section as the upper leadership model,and the lay operation scheduling model is the lower follow model,a bi-level optimization model is established.The preliminary packing solution solved by the upper layer model is puted into the lower layer layup scheduling model,and the lay-up operator's ratio of the filled parts in the support of each layer and the work station selection of the parts are obtained.Then,the results of the stacking operation scheduling of the lower layer following model are fed back to the upper model.Based on the feedback,the upper model combines the two brackets to form a tank plan and revises the preliminary boxing plan of the brackets in the tank layout plan,and outputs the optimal tank plan and stacking.The result of job scheduling is used as the final production scheduling plan.To sum up,this thesis studies on the production scheduling problem of aviation composite parts.Semi-continuous production characteristics of aviation composite parts is analyzed.A bi-level scheduling optimization model for two core processes of hot press forming and manual layup is designed,and the corresponding solution algorithms are developed.The case analysis shows the feasibility and effectiveness of the method.