Lean-Safety Six-Sigma

Industries in developing countries suffer from a major crisis which is the competition at international markets due to low of product quality  and raising the costs of production. The product loses its value in markets, because of delays and the failure to meet customers’ demands on time and/or the low level of quality. These are the most problems that face the production lines. The first problem is resulted from some of the production’s waste types which are unspecified in their definitions, the dominant factor of these waste types is a time that consumes in setups, maintenance operations, tool changing and/or inspection processes (all these so-called the machine downtime), which considers a “Necessary Non-Value Add” time and leads to wrong decision-making in the wrong time. The “Necessary Non-Value Add” has uncertain behavior due to the human interference, and is occurred periodically. Therefore, this work predicts the machine down-time and reduces its time to achieve the continuity of the workflow. The second problem is resulted from a lack in system calibration for the machines.

The Lean philosophy adopted the reduction of the total cycle time and the causes which decrease the productivity, and the six-sigma methodology is used to reducing the variations that decrease the quality of the output. To speed productivity, minimize the output’s variation, raise labor’s utilization and improve 5’S stages. This work proposes a Defect and Time Control algorithm which is a section of Fuzzy Lean and Six Sigma model that depends on analyzing the critical data inputs, evaluating the level of the solution and controlling the waste of defects and time aspects in work flow. The fuzzy intervenes in case of uncertain data inputs or in the tie case to choose the most favorable result, taking into account some of uncertain variables.

The work has been reviewed in five chapters and concluded some results, which achieved by the proposed Fuzzy Lean and Six Sigma model. This model is divided into two phases, the first phase reducing Necessary Non-Value Add time waste and the internal handling and transportation costs approximately 13% using procedures via two consecutive sections. The first aims to improving 5’S technique via Sorting, Set-in-order (tools/tasks) and make them in Safety to compensate for traditional ways and reduce the handling. The second aims to reducing the waiting time and idle time waste approximately 15% via Increase Labor Utilization rule which is a fuzzy heuristic algorithm. The Increase Labor Utilization rule generates a fuzzy index that helps increase the labor’s utilization by resorting tasks/labor in linked cells to increase the machine’s availability. These improvements come not only from treating the scheduling problem but also from the rescheduling in two cross-linked points. The second phase proposes a formula via applying Best Setup procedures for calibrating machines by specific input values to pre-set outputs as expected with minimum variation. The consumed time in the inspection process is reduced by the same procedures. The sigma level is increased from 4.35 to 5.65. This phase ensures the Standardization in 5’S and provides the Stop action if any deviation appears during process running. The main objectives of this work is evaluating, reducing and controlling waste types through their time that are considered dependent variables which have uncertain description.