Thesis (M.Sc.) - Cairo University - Institute of Statistical Studies and Research - Department of Statistical Quality Control and Quality Assurance

Traditional production systems suffer from many problems like waste of raw materials, losses of the time, reduction of the availability of equipments, low productivity, lower product quality (rework- customer complaints). All these draw backs lead to increase in production costs, low customer loyalty and decrease the chance for competition. To overcome these drawbacks, a set of methodologies have been proposed for continuous improvements of operations. Lean Six Sigma is one of process improvement methodologies. It is seen as the latest philosophy of continuous improvement in many companies world-wide. Lean Six Sigma is a combination of two philosophies: Lean Manufacturing philosophy introduced by the Toyota Production System and Six Sigma philosophy introduced by Motorola{u2019}s submission in the late 1980{u2019}s. Essentially, Lean and Six Sigma have been combined since individually they cannot deal with all circumstances of problems. Generally, Lean focuses on speed and efficiency. It suggests eliminating waste and reducing non-value-adding activities. On the other hand, the focus of Six Sigma is on quality and effectiveness. Helwan Diesel Engines Company is the only factory in Egypt for diesel engines production. The factory suffers from low efficiency and effectiveness.The performance of the production system at the engines assembly line suffers from increased number of defective and rejected engines. The rate of rejected engines was 20 % that means the operations level was 2.34 sigma. To overcome this problem, the study applied Lean Six Sigma through the DMAIC methodology with selected tools at each phase

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