Flow Back The possibility for a revenue opportunity benefit depends on the system response to a flow-time reduction. The description of this is beyond the scope of our paper. Needless to say, we Quality thesis manufacturing aircraft at best give a high-level overview of the methodology, concepts and planning tools.
Boeing commercial airplane group maintains a multi-year order backlog.
Description The assembly of an airplane entails a synchronized series of manufacturing processes which are organized as a network of concurrent and merging flows.
For instance, in Figure 2 we show for a typical airplane how costs accumulate over the flow time for completing the airplane. After this very first plane, the schedules for all subsequent work centers are thereby advanced by one day. An airline ordering a Boeing in was not going to get delivery of the airplane until approximately For example, at the time this research was donedemand exceeded supply in the commercial airplane industry.
Unlike manufacturing flow time, all work centers within the manufacturing system operate with the same production cycle time i.
As a result the number of job positions occupied by planes will vary between three and two over the three day cycle.
Consider a work center with eight days of flow time and a four-day cycle time, and suppose it reduces its flow time by one day. We see from Figure 2 that a reduction in flow times will change the cumulative product cost curve, and presumably reduce the inventory holding cost per plane.
This research examines how these ideas apply to aircraft manufacturing and provides a case study for addressing flow-time issues.
Consequently, every work center must also complete work on an airplane every three days, no matter what the individual Quality thesis manufacturing aircraft time of the work center is. Flow Through Illustration We illustrate in Figure 3 how we can pull a flow-time reduction through the manufacturing process.
That is, the one-day reduction in flow time allows all upstream work centers to shift their schedules by one day. The number of job or tool positions required within a work center is the flow time divided by the production cycle time, rounded up to the next largest integer.
Different work centers within the manufacturing sequence can have and will have different flow times. For a fixed-rate delivery schedule, each work center will "ship" its assembly or subassembly to the next work center according to a fixed schedule driven by material handling considerations; Boeing will monitor how often these shipments are done before all of the work has been completed at the prior work center.
Flow Time Cost Elements We consider three types of flow-time costs: Inventory Carrying Cost The inventory holding cost for carrying the work-in-process WIP inventory includes the opportunity cost for the money tied up in the inventory, plus storage costs, insurance, spoilage and obsolescence costs.
These manufacturing processes are organized into a network of work centers or departments, known as control codes at Boeing.
The number one flow chart depicts the exact sequence of every work center in the airplane manufacturing process see Figure 1 ; there is a new number one flow chart for each new airplane program, model derivative, or new production rate. Thus, the first type of flow-time cost is the inventory holding cost for the work-in-process.
For instance, in this example it may be possible to have flow times of twelve days and three crews, each with nine workers. We then present regression analyses that relate system variances to the direct labor content and discuss the implications for a longer-term strategy for flow-time reduction.
Specifically, we describe the organization of the manufacturing processes for airplane assembly and the methods for planning and scheduling the assembly operations. We term these responses as "flow back" or "flow through," respectively.
The so-called optimal crew size is the number of workers at the work center that minimizes the direct labor input per job.
For instance, if the cycle rate is one plane every four days and the flow time is ten days, then there must be three positions.
A new plane will enter the work center every four days and a completed plane will exit every four days:LEAN SIX-SIGMA APPLICATIONS IN AIRCRAFT ASSEMBLY A Thesis by Siddhartan Ramamoorthy B.E, Mechanical Engineering, University of Madras, India, Submitted to the Department of Industrial & Manufacturing Engineering Wichita State University achieving the fastest rate of improvement in customer satisfaction, cost, quality.
total quality management (TQM) and organisational characteristics (size, type of the manufacturing and service sectors, have adopted quality strategies, and made TQM a well accepted part of almost every manager’s ‘tool kit’ (Dow, Swanson, & Ford, ).
This thesis focuses on aircraft wing box manufacturing in particular in which relatively little automation has been implemented to date. There are many challenges associated with automating the wing box.
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Jackson S. Chao Boeing Company we found that engineering has an important indirect impact on direct manufacturing hours through the effects that the quality of engineering release has on high-impact variances such as defects.
"Analysis of Variance Impact on Manufacturing Flow Time," S. M. COST MODELLING FOR MANUFACTURING OF AEROSPACE COMPOSITES SCHOOL OF APPLIED SCIENCES MSc by Research Thesis January CRANFIELD UNIVERSITY SCHOOL OF APPLIED SCIENCES MSc by Research Thesis Academic Year - WEITAO MA Cost Modelling for Manufacturing of .Download