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What is Six Sigma?

Six Sigma is a management system that strives to achieve near-perfection in terms of quality. In statistical terms, a process that produces 3.4 defects per million opportunities or less (i.e. near perfect outcome in quality) is called a Six Sigma process. Or in other words, 99.99966% of the products produced by a Six Sigma process are expected to be defect-free.

A Brief History

The use of statistics in industrial problem-solving can be traced back to inter-war period in the US and post second world-war Japan by luminaries such as Walter Shewhart, W. Edwards Deming, Joseph Juran, Phillip Crosby, Kaoru Ishikawa and Genichi Taguchi among others. The concepts of Total Quality Management and Zero-defect propounded by them were precursors to Six Sigma. The term Six Sigma was coined by Bill Smith of Motorola in 1986 and later widely implemented at General Electric and Honeywell in mid-to-late 1990s. It has since been adopted across various organisations in vastly diverse industries (manufacturing, pharmaceuticals, banking & insurance, shipping, healthcare etc.) the world over.

A Basic Overview

The sigma in “Six Sigma” stands for standard deviation, which is the most common measure of variation. Variation is inherent in any process, but must be reduced to produce consistent, stable and predictable results. Six Sigma approach strives to identify and eliminate or control the causes of variation.

Customer’s requirements and specifications form the focal point of Six Sigma approach. Always meeting the customer’s specifications, then, becomes the goal. Let us try to understand the underlying statistics behind Six Sigma thinking through an example –

Suppose that a customer sets the specification for the length of a widget to be 10 + or – 0.3 cm. This is to say, the any widget with a length between 9.7 cm and 10.3 cm would be deemed acceptable by the customer, and any widget outside this range would be deemed a defective unit by the customer.

Now, the manufacturer of the widget produces parts with an average length (mean) of 10 cm and a standard deviation of 0.05 cm (i.e. variation from the mean). Now, six standard deviations to either side (6*0.05) from the mean for this process is 9.7 cm to 10.3 cm. This would indicate that the manufacturer’s process is a Six Sigma process and is very capable of meeting the customer’s requirements. The probability of producing a faulty or defective unit in this case is 3.4 out of 1,000,000.

Ultimately, reducing variation in the process leads to greater customer satisfaction as a result of meeting customer’s quality expectations. This in turn results in significant cost savings for the company.

Six Sigma Approach and Tools

We’ve seen that we must reduce variation in the output. How then, to identify the causes of variation and eliminate or control them?

Six Sigma methodologies espouse a structured way of problem solving. Foremost among them is the DMAIC approach (explained below):

Define – Define the problem; set target, identify the scope of the project, resources required, potential constraints etc.

Measure – Check effectiveness of the measurement system, measure “current-state” conditions, and collect data.

Analyse – Analyse the data to identify potential root causes of variation.

Improve – Validate and implement solutions to the root causes of variation and

Control – Implement control measure to prevent the problem from reoccurring.

This is the approach expected to be followed by a Six Sigma project team (usually a cross-functional team) working on process improvements. A typical Six Sigma project is expected to last 2-3 months and shows significant improvement in the process after this period.

There are various statistical and other problem-solving tools to aid the project team at each of these stages. Common among them are –

Process Mapping, Gage R&R,  7 Basic QC tools (Check Sheets, cause & effect diagrams, scatter plots, Pareto charts, histograms, graphs/ charts and control charts), hypothesis testing, regression & ANOVA, design of experiments (DOE), process capability, Taguchi methods etc.

Organisational Structure

Six Sigma approach requires individuals from various levels of an organisation to be engaged in process improvement with clearly defined roles and responsibilities. These are described below (courtesy of www.isixsigma.com) –

Sponsor Senior executive who sponsors the overall Six Sigma initiative. Ensures alignment between customer’s expectations and company’s goals.
Leader Senior-level executive who is responsible for implementing Six Sigma within the business.
Champion Middle- or senior-level executive who sponsors a specific Six Sigma project, ensuring that resources are available and cross-functional issues are resolved.
Master Black Belt Highly experienced and successful Black Belt who has managed several projects and is an expert in Six Sigma methods/tools. Responsible for coaching/mentoring/training Black Belts and for helping the Six Sigma leader and Champions keep the initiative on track. Dedicated 100% of his/her time to Six Sigma initiative.
Black Belt Full-time professional who acts as a team leader on Six Sigma projects. Typically has four to five weeks of classroom training in methods, statistical tools and sometimes team skills. Dedicates 100% of his/her time towards the Six Sigma initiative. Also trains and mentors Green Belts
Green Belt Part-time Six Sigma professional who participates on a Black Belt project team or leads smaller projects in addition to his/her functional responsibilities. Typically has two weeks of classroom training in methods and basic statistical tools.
Team Member Professional who has general awareness of Six Sigma (through no formal training) and who brings relevant experience or expertise to a particular project.
Process Owner Professional responsible for the business process that is the target of a Six Sigma project.
 

Benefits to an Organisation

Six Sigma provides an organisation a customer-focused & structured problem solving approach and an ethos of continuous improvement. It is predominantly geared towards quality improvement, which in turn improves customer satisfaction. In addition to customer satisfaction and retention, significant cost savings are usually achieved by reducing scrap, defects, improving cycle times and numerous other process improvements. Furthermore, the Six Sigma process can be applied to product and process development efforts as well with an eye towards in-built quality (Design for Six Sigma or DFSS). Motorola estimates that it has saved $17 billion to date through Six Sigma. Jack Welch, former CEO of General Electric remarked that “Six Sigma is the most important initiative GE has ever undertaken”.

A word of caution – Six Sigma tools, ultimately, must be used for a small and select bunch of projects only by those professionals trained in Six Sigma and statistical problem solving, and must not be used for every process improvement project. As a general rule of thumb, it is thought that 90% of problems in a process could be solved using common sense and Kaizen tools & methodologies, leaving only 10% of the intractable issues to be resolved using Six Sigma tools (i.e. use these tools only when all other avenues are exhausted).

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Organizing the Work Place

It’s difficult to find out the paper I wanted. I can see papers everywhere but not the one I wanted. Puzzling is, how my secretary manages to find out! Tea stains on table surface, dust layers on monitor, over-stuffed file cabinets, and cartons of papers on floor….

Is this quite common? How many of us are working in a place that is filled with dirt & debris (be it office or shop-floor)? People working in such conditions consider searching as a part of their routine. “Who knows where” is highly valued. Is this right? Is there a solution?

5S is an initiative that enables you turnaround a workplace cleaner & safer apart from making your job simpler and satisfying. “5S method”, as it is called refers to five Japanese words: seiri (sort), seiton (set in order), seiso (Shine), seiketsu (Standardization), and shitsuke (Self-discipline or Sustain). Translated or transliterated, into English, they all start with the letter “S”. 5S is all about how to organize a work place for efficiency and effectiveness, clearing the clutter as to find items without searching, cleanliness and sustaining the new order.

Origin:
Mr. Hiroyoki Hirano has formulated the concepts and tools of the 5S system. He wrote a book 5 Pillars of the Visual Workplace for Managers that was readily accepted by the management of manufacturing companies. So, we can say 5S is originated from Japan.

Even before Mr. Hirano formulated 5S, Ford Company was practicing similar initiative which they called “CANDO”. C meant Cleaning the Clutter, A for Arranging & Organizing, N for Neatness, D for Discipline and O for Ongoing Improvement.

The glaring difference between CANDO and 5S is Standardization. Mr. Hirano felt that without Standardization, Sustenance too, would be a problem. He believed that Standardization builds understanding among employees of how they should do the work.

No continuous improvement initiative will sustain without Standardization & Self-Discipline.

5S provides a structure for improvement programs. It can be termed as the DNA for any continuous initiative program. 5S is an ice-breaker exercise that enables the success of cross functional teams. The biggest myth among 5S implementers is that 5S is a step by step activity. Certainly not! 5S cannot be implemented in steps. All the elements of 5S should go together.

Logical decision of trashing the not needed is required just like our body removes the unwanted things every morning. Imagine our body fails to remove the waste from our body for a day! Similar situation would arise in our workplace if unwanted items are not removed. Distinguishing what is needed and what is not becomes difficult as one has the tendency to hang onto the possessions. Added to the logical decision of trashing, classifying items into needed but not now; but not here; but not this much paves way for effective Seition. Red-Tagging on items where decisions could not be taken at certain levels bring in the involvement of higher authorities.

Managers had always recognized the need to decide upon locations for materials and tools. However, they were unclear about what to do with the non-essential items – whether to remove, stored elsewhere or trashed. 5S makes a clear distinction by differentiating between Seiri and Seiton. 5S makes it clear that any effort to consider setting in order (a layout change of flow creation) before the removal of the unnecessary items would lead to a sub-optimal solution!

Similarly, Seiso, or cleanliness, is a distinct element of the change program that can transform a process area. As per 5S, the definition of a cleaning methodology (Seiso) is a discrete activity. Breaking down the improvement activity in this way clarifies that the requirements for the cleanliness regime must be understood as a factor in the conceptual stage of Seiton.

Change can be introduced and people might adapt to the changes as long as the Management drives it. It slips as the focus is lost from the top. Standardization or Seiketsu, helps us in maintaining the focus. With Standardization, the behavioral pattern changes and hence a cultural change is brought in. Shitsuke or Self-discipline is a distinct approach to bringing about a new way of working.

The identified benefits from 5S can be regarded as falling within the Kaizen portfolio – that is, they are all based around the elimination of waste in one form or another and enhancing the performance. The most obvious benefit from items being organized in such a way is that of improved productivity. Another benefit of 5S is improved plant maintenance – workers ‘owning’ a piece of plant, responsible for keeping it clean and tidy, can take ownership for highlighting potential problems before they have an impact on performance. The next is Quality. Obviously, dirt is not welcome in any organization and it is needless to mention that a cleaner environment improves the quality. Imagine where your goods are supplied along with a soiled Invoice! What do we project about our organization?

Next to follow is improved Safety. Clear pathways between workbenches and storage racks can minimize accidents, so does neatly-swept floors. Improving the layout of the facility merges with the concept of visual management; if one can see the status of plant and of work in the facility, then benefits will accrue as the complexity of communication and its gaps are eliminated. 5S can also be a valuable sales tool when potential customers visit; a well-organised, clean and tidy facility sends a message of a professional and well-organized supplier.

Let’s get started with 5S as this is the first step for any continuous improvement initiative.