What is Six Sigma?
What is Six Sigma?
The concepts surrounding the drive to Six Sigma quality are essentially those of statistics and probability. In simple language, these concepts boil down to, “How confident can I be that what I planned to happen actually will happen?” Basically, the concept of Six Sigma deals with measuring and improving how close we come to delivering on what we planned to do.
Anything we do varies, even if only slightly, from the plan. Since no result can exactly match our intention, we usually think in terms of ranges of acceptability for whatever we plan to do. Those ranges of acceptability (or tolerance limits) respond to the intended use of the product of our labors–the needs and expectations of the customer.
Here’s an example. Consider how your tolerance limits might be structured to respond to customer expectations in these two instructions:
“Cut two medium potatoes into quarter-inch cubes.” and “Drill and tap two quarter-inch holes in carbon steel brackets.”
What would be your range of acceptability–or tolerances–for the value quarter-inch? (Hint: a 5/16” potato cube probably would be acceptable; a 5/16”threaded hole probably would not.)Another consideration in your manufacture of potato cubes and holes would be the inherent capability of the way you produce the quarter inch dimension–the capability of the process. Are you hand-slicing potatoes with a knife or are you using a special slicer with preset blades?
Are you drilling holes with a portable drill or are you using a drill press? If we measured enough completed potato cubes and holes, the capabilities of the various processes would speak to us. Their language would be distribution curves.
Distribution curves tell us not only how well our processes have done; they also tell us the probability of what our process will do next. Statisticians group those probabilities in segments of the distribution curve called standard deviations from the mean. The symbol they use for standard deviation is the lower-case Greek letter sigma.
For any process with a standard distribution (something that looks like a bell-shaped curve), the probability is 68.26% that the next value will be within one standard deviation from the mean. The probability is 95.44% that the same next value will fall within two standard deviations. The probability is 99.73% that it will be within three sigma; and 99.994% that it will be within four sigma.
If the range of acceptability, or tolerance limit, for your product is at or outside the four sigma point on the distribution curve for your process, you are virtually assured of producing acceptable material every time–provided, of course, that your process is centered and stays centered on your target value.
Unfortunately, even if you can center your process once, it will tend to drift. Experimental data show that most processes that are in control still drift about 1.5 sigma on either side of their center point over time.
This means that the real probability of a process with tolerance limits at four sigma, producing acceptable material is actually more like 98.76%, not 99.994%.
To reach near-perfect process output, the process capability curve must fit inside the tolerances such that the tolerances are at or beyond six standard deviations, or Six Sigma, on the distribution curve. That is why we call our goal Six Sigma quality.
Quality makes us strong
In the past, conventional wisdom said that high levels of quality cost more in the long run than poorer quality, raising the price you had to ask for your product and making you less competitive. Balancing quality with cost was thought to be the key to economic survival. The surprising discovery of companies which initially developed Six Sigma, or world-class, quality is that the best quality does not cost more. It actually costs less. The reason for this is something called cost-of-quality. Cost-of-quality is actually the cost of deviating from quality–paying for things like rework, scrap and warranty claims. Making things right the first time–even if it takes more effort to get to that level of performance–actually costs much less than creating then finding and fixing defects.
Shooting for Six Sigma:
An illustrative fable
The underlying logic of Six Sigma quality involves some understanding of the role of statistical variation. Here’s a story about that. Robin Hood is out in the meadow practicing for the archery contest to be held next week at the castle. After Robin’s first 100 shots, Friar Tuck, Robin’s Master Black Belt in archery, adds up the number of hits in the bull’s eye of each target. He finds that Robin hit within the bull’s eye 68% of the time.
Friar Tuck plots the results of Robin’s target practice on a chart called a histogram. The results look something like this. “Note that the bars in the chart form a curve that looks something like a bell,” says the friar. “This is a standard distribution curve. Every process that varies uniformly around a center point will form a plot that looks like a smooth bell curve, if you make a large enough number of trials or, in this case, shoot enough arrows.”
Robin scratches his head. Friar Tuck explains that Robin’s process involves selecting straight arrows (raw material); holding the bow steady and smoothly releasing the bowstring (the human factor); the wood of the bow and the strength of the string (machinery); and the technique of aiming to center the process on the bull’s eye (calibration and statistical process control).
The product of Robin’s process is an arrow in a target. More specifically, products that satisfy the customer are arrows that score. Arrows outside the third circle on these targets don’t count, so they are defects. Robin’s process appears to be 100% within specification. In other words, every product produced is acceptable in the eyes of the customer.
“You appear to be a three- to four-sigma archer,” the friar continues. “We’d have to measure a lot more holes to know for sure, but let’s assume that 99.99% of your shots score, that you’re a four sigma shooter.” Robin strides off to tell his merry men.
The next day, the wind is constantly changing directions; there is a light mist. Robin thinks he feels a cold coming on. Whatever the reason, his process doesn’t stay centered on the mean the way it did before. In fact, it drifts unpredictably as much as 1.5 sigma either side of the mean. Now, instead of producing no defects, after a hundred shots, Robin has produced a defect, a hole outside the third circle. In fact, instead of 99.99% of his shot scoring only 99.38% do.
While this may not seem as if much has changed, imagine that, instead of shooting at targets, Robin was laser-drilling holes in turbine blades. Let’s say there were 100 holes in each blade. The probability of producing even one defect-free blade would not be good. (Because the creation of defects would be random, his process would produce some good blades as well as some blades with multiple defects.)
Without inspecting everything many times over (not to mention spending an enormous amount for rework and rejected material), Robin, the laser driller, would find it virtually impossible to ever deliver even one set of turbine blades with properly drilled holes.
Not only would the four-sigma producer have to spend much time and money finding and fixing defects before products could be shipped, but since inspection cannot find all the defects, she would also have to fix problems after they got to
the customer. The Six Sigma producer, on the other hand, would be able to concentrate on only a handful of defects to further improve the process.
How can the tools of Six Sigma quality help? If Robin the archer were to use those tools to become a Six Sigma sharpshooter instead of a four-sigma marksman, when he went out into the wind and rain, he would still make every
shot score. Some arrows might now be in the second circle, but they would all still be acceptable to the customer, guaranteeing first prize at the contest. Robin the laser driller would also succeed; he would be making virtually defect free turbine blades.
The steps on the path to Six Sigma quality:
1. Measurement
Six Sigma quality means attaining a businesswide standard of making fewer than 3.4 mistakes per million opportunities to make a mistake.
This quality standard includes design, manufacturing, marketing, administration, service, support–all facets of the business. Everyone has the same quality goal and essentially the same method to reach it. While the application to engine design and manufacturing is obvious, the goal of Six Sigma performance–and most of the same tools–also apply to the softer, more administrative processes as well.
After the improvement project has been clearly defined and bounded, the first element in the process of quality improvement is the measurement of performance. Effective measurement demands taking a statistical view of all processes and all problems. This reliance on data and logic is crucial to the pursuit of Six Sigma quality.
The next step is, knowing what to measure. The determination of sigma level is essentially based on counting defects, so we must measure the frequency of defects. Mistakes or defects in a manufacturing process tend to be relatively easy to define–simply a failure to meet a specification. To broaden the application to other processes and to further improve manufacturing, a new definition is helpful: a defect is any failure to meet a customer satisfaction requirement, and the customer is always the next person in the process.
In this beginning phase, you would select the critical-to-quality characteristics you plan to improve. These would be based on an analysis of your customer’s requirements–(usually using a tool like Quality Function Deployment.) After you clearly define your performance standards and validate your measurement system (with gage reliability and repeatability studies), you would then be able to determine short-term and long-term process capability and actual process performance (Cp and Cpk).
2. Analysis
The second step is to define performance objectives and identify the sources of process variation. As a business, we have set Six Sigma performance of all processes within five years as our objective. This must be translated into specific objectives in each operation and process. To identify sources of variation, after counting the defects we must determine when, where and how they occur. Many tools can be used to identify the causes of the variation that creates defects.
These include tools that many people have seen before (process mapping, Pareto charts, fishbone diagrams, histograms, scatter diagrams, run charts) and some that may be new (affinity diagrams, box-and-whisker diagrams, multivariate analysis, hypothesis testing).
3. Improvement
This phase involves screening for potential causes of variation and discovering interrelationships between them. (The tool commonly used in this phase is Design of Experiment or DOE.) Understanding these complex interrelationships, then allows the setting of individual process tolerances that interact to produce the desired result.
4. Control
In the Control Phase, the process of validating the measurement system and evaluating capability is repeated to insure that improvement occurred. Steps are then taken to control the improved processes. (Some examples of tools used in this phase are statistical process control, mistake proofing and internal quality audits.)
Words of Wisdom about Quality
If you believe it is natural to have defects, and that quality consists of finding defects and fixing them before they get to the customer, you are just waiting to go out of business. To improve speed and quality, you must first measure it–and you must use a common measure.
The common business-wide measures that drive our quality improvement are defects per unit of work and cycle time per unit of work. These measures apply equally to design, production, marketing, service, support and administration.
Everyone is responsible for producing quality; therefore, everyone must be measured and accountable for quality. Measuring quality within an organization and pursuing an aggressive rate of improvement is the responsibility of operational management.
Customers want on-time delivery, a product that works immediately, no early life failures and a product that is reliable over its lifetime. If the process makes defects, the customer cannot easily be saved from them by inspection and testing.
A robust design (one that is well within the capabilities of existing processes to produce it) is the key to increasing customer satisfaction and reducing cost. The way to a robust design is through concurrent engineering and integrated design processes.
Because higher quality ultimately reduces costs, the highest quality producer is most able to be the lowest cost producer and, therefore, the most effective competitor in the marketplace.
About the Author
Steven Bonacorsi is a Senior Master Black Belt instructor and coach. Steven Bonacorsi has trained hundreds of Master Black Belts, Black Belts, Green Belts, and Project Sponsors and Executive Leaders in Lean Six Sigma DMAIC and Design for Lean Six Sigma process improvement methodologies.
Bonacorsi Consulting, LLC.
Steven Bonacorsi, President
Lean Six Sigma Master Black Belt
14 Clinton Street
Salem NH 03079
sbonacorsi@comcast.net
603-401-7047
How-to: Select Arrows
archery arrows charts
How to choose a bow that can arise Buck Award
The ability to draw is property acquired through self-discipline and strict compliance with methods approved range. The content of this article is intended to guide beginners in the purchase of archery equipment right to help you become the person an expert marksman.
Whenever archers get together, there are always those who would have us believe that since our ancestors fired five fifty arches thousand years ago that we moderns can shoot a bow instinctively. Others think that everything we have to do to achieve a goal or a bag of our money is to a deep breath, look at the target, reducing the arrow in the ear, and shot him. However, it takes a lot of practice perfect skills necessary to land the dollar price.
The arc has been developed in recent years. Now there are more varieties available ever. Because of the variety of materials used for the construction of bows and arrows all varieties to choose, choose an arc `s right for you can be a difficult task. Here are the basics that every beginner must know before he or she goes shopping for the arc ideal for a big money.
If the archers did not mention among his acquaintances, a question addressed to the Office of State must bear the name and address game archery your organization and your state in turn, could advise clubs have facilities for target range or shooting in your area, or the name of an archer who will be happy to help your feet feel firmly established in the firing line.
Remember, most arcs destination for men who are experienced archers do not exceed 45 pounds in weight change. Ladies rarely used an arc of more than 30 pounds. A beginner should not try to use these weight design for learning to take a bow. A guide for determining appropriate weight range to use on your first attempt at archery is as follows: youth at the age of 10 but not exceeding 15 pounds, 10 to 16 years of age, 20 to 25 pounds, more than 16 years, 25 to 30 pounds. Once you've selected your bow, the table below will help you choose the right to match the arrows of the same.
A basic rule that the beginner must have before him at any time, is that the arc is not a showdown, but a game of skill, and enjoy shooting a bow, skills must be acquired. As with any what other sport, fitness is acquired by practice the correct procedure at all times. The scores are not only better shooting. The technique is most important, and is obtained by observing the performance of archers in the line of fire, personal advice and instructions. Now that you know how to choose a bow and arrows for a proper fit, just a little practice and will be priced Home money to mount on the wall.
About the Author
Who Else Wants The Secret To Have Your
Archery Equipment Scores Improve
Dramatically in 30 Days or
Less GUARANTEED
http://www.archeryequipment.org/
AMERICAN BLIND ARCHER Austin Beaumount SHOOT BLINDFOLD
archery arrows charts
Mars and Neptune Trine & Moon into Leo & Sun Quincunx Uranus & Mars Square Uranus(August 18 -19, 2009)
Mars is our warrior spirit! Mars stands for our life force energy and how we are able to apply ourselves in our life. In whatever sign and house the Mars is in your horoscope as well how he is connected with the other inner planets will give you a pretty good idea and guidance towards understanding your energy flow and your health.
Mars is a pretty forward guy! You give him a goal and he is moving towards it like the arrow released from the bow. In the practice of Zen archery it is the most important part to become one with the aim and for that you need to know your aim. For Mars to be truly the successful warrior spirit for you, you need to give him his direction to go. You are the super brain and he is the muscle.
The Trine between the Mars and Neptune
This is a perfect harmonious energy flowing connection between Mars and Neptune. Neptune, the visionary and dreamer is fueling the actions of Mars and widens the possibilities. If we clearly know why we want to go somewhere, the how will take care by itself in a step to step way. Keep your aim in mind, feel how it will be to have reached your goal and those feelings will keep you aligned with the flow going there.
Mars Square to Uranus and Sun Quincunx Uranus
These aspects with Mars, Sun and Uranus are of different and very challenging matter. Uranus can rock our world on Tuesday. These aspects could show us a tendency to be more prone to accidents then usual. Running into edges and table corners, the energy is so much faster then the body can keep up with it. The general energy flow is highly charged, explosive, might change abruptly in direction and make us impatient or rude.
To find a good way to channel those unruly energies is to find another way of using them up. The classic Uranus sport is flying, jumping out of the heavens with a parachute or a bungee, paragliding; all things you might not feel inclined to do.
But you could try to find a new way of expressing your energy flow through exercising. You know exercising is a good thing and you need to make time for it!!
Try out something new (Uranus) and different from what you usually do. Take the aim that for a whole week you will be trying out a new gym facility or take walks every day, or go swimming, or take a lesson in fencing or riding. Be creative and push your envelope and you will have a lot of fun with channeling this otherwise challenging energy combination.
Moon into Leo
The Moon in Leo is carrying us with optimism and good spirits. We feel we can do what we want to do and find ample opportunities to let our creativity flow into our real life ventures. Leo people are very confident and usually don’t suffer under deficiency or self-doubts. We can borrow a little from their confident spirit with this Moon position for these two days.
This is a good time to take that step forward and risking yourself a little more, beyond your usual self perception and self-image.
Astrology Conference
I will be flying out today from Maui to Chicago to take part in the ISAR conference. I am a member of ISAR and it stands for the International Society of Astrological Research. There is a big international conference 19th to the 24th of August 15, 2009 for astrologers and laypeople who are interested in the matters of astrology.
I have some prewritten articles prepared for you on my blog to keep you informed of the heavenly activities as usual.
I am looking forward to come back full of fresh ideas and higher levels of perception and awareness for my own astrological practice.
If you like my astrological musings I invite you to find more on my Astrological Signs Weather Report & Healing Gems Blog for a regular update on the universal flow in the heavens. I am also very passionate about the abilities of the healing gemstones to help to align and balance our flow. I have even written a book about it and the connection with astrology! If you know where your challenges are, you can then take steps to support or balance yourself with gemstones, if that is something that appeals to you.
I hope you enjoyed this post, aloha and many blessings, Shakti.
Shakti Carola Navran: astrologer, jeweler and author
About the Author
Shakti Carola Navran is originally from Germany, living in Maui, Hawaii, is a professional jeweler, astrologer and author with a lifelong spiritual journey; she has been crafting personalized Soul Jewelry since 1977.
In her book Jewelry and Gems for Self-Discovery: Choosing Gemstones that Delight the Eyes & Strengthen the Soul she teaches you about how to read your personal horoscope and blue print for your life. Then you will be able to balance yourself in your most important areas with your 12 main healing gemstones, you could call your true birthstones.
Jewelry and Gems for Self-Discovery is a treasure chest of ideas on how to select, purchase, and wear jewelry that will enhance your body, heart, mind, and soul. Find out more about it on her website http://www.JewelryandGemsforSelfdiscovery.com and see her astrological weather report at http://www.jewelryandgemsforselfdiscovery.com/blog/ .
AMERICAN BLIND ARCHER Austin Beaumount SHOOT BLINDFOLD
