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The term Six Sigma Quality came form Motorola. Actually, the term Sigma, is a statistical expression that indicates how defect free a process or a product is. Let us say, there are 10 steps to make a product. Each step is an opportunity to make a defect. Thus, if 100,000 pieces of the given product are manufactured, there will be a million opportunities to make defects. If, for instance, we are at three Sigma level, there could be 66,807 defects per million opportunities. At Six sigma, the defect rate drops to 3.4 defects per million. This is called Six Sigma Quality. Average processes & products operate at three sigma level. The Best in class processes and products are at Six Sigma level. The following Table provides the co-relation of Defects per million opportunities to Sigma.
Hence, it can be concluded that, higher the sigma levels, higher the Quality. | |||||||||||||||
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Every Organization houses a hidden factory which produces Waste. Even in successful Organizations the extent of waste is as high as 15 to 30 % of sales. Waste occurs because defects occur. How do we drive defects away? defects can be driven away only when we measure them andget to know our existing condition. Then we can Analyze why those defects occur and implement Improvements to take us to the " Should Be " condition. The essence of six sigma Quality is defect reduction & cycle time reduction. For defect reduction two methodologies are used.
For cycle time reduction Cross functional process mapping is used. | |||||||||||||||
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Six Steps to Six Sigma is a method to reduce defects. This method was developed by Motorola to improve its processes. This method is applicable for transaction oriented operations. Examples of such operations are:
In above examples each distribution of a Payslips,fixing of each bug reported by customer & each training session is a transaction. Six Steps to Six Sigma provides a method to Improve the way existing operations are done, so that defects are prevented. This method will finally lead to customer satisfaction, whether he/she is an internal or an external customer . The six steps to six sigma are listed below: Step-1:Identify the product you create or service you provide. Step-2: Identify the customer(s) for your product or service and determine what they consider important Step-3: Identify your needs to provide product/service so that it satisfies the customer Step-4: Define the process for doing the work Step-5: Mistake proof the process and eliminate Wasted effort Step-6: Ensure continuous Improvement by measuring, analyzing and controlling the improved process | |||||||||||||||
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Design for manufacturability (DFM) is a method -for creating robust product designs that will be insensitive to long-term dynamic variation in the processes & materials used in manufacturing. - will be immune to foreseeable misuse of the product in the environment Some of the success stories of DFM are:
The Design for manufacturability supports the key initiatives of Six Sigma Quality & Cycle time reduction. The DFM uses Six steps , similar (but not same to Six Steps to Six Sigma used for Transactional Quality. It is noticed that 10 to 25 percent of sales income is spent on repair and rework as an effect of not designing for manufacturability. Some examples are listed below:
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Cross-functional process mapping is a method used to reduce cycle time of critical operations which span multiple functions within an organization. Examples of such operations are:
The cross-functional process mapping involves identifying direct value added activities & non value added activities in a selected cross-functional process & re-design the entire process eliminating non value added activities & bottle necks. By doing this the entire cycle time from start to end will reduce. The major benefits of cross-functional process mapping are:
It is found that by doing a cycle time reduction, using cross functional process mapping method in manufacturing function ,a reduction of 60 % in cycle time can be achieved. In Administrative & service functions the cycle time reduction that can be achieved is as high as 80 %. |