Minimize Variation and Run to Optimum Target!

The holy grail of every manufacturing process.

Minimize variation – the customer sees, feels, smells, uses the same product every time without noticing a difference – no surprises – expectations are met.  This is a very important consideration for the manufacturing of sub-components like a car part or materials to be combined together like diapers.  It is important that raw materials, to a high speed conversion process like diapers, be the same each time – low variation – or the performance of the line will be affected and efficiency decreased.

Run to optimum target – this addresses both the cost and the perception of value.  If you are not hitting target on process, product or quality variables, then costs may be impacted affecting critical margins.  In terms of perception of value, consider fill weights for products displayed on a grocery shelf. When you walk up to select a product, you subconsciously scan the shelve and typically pick the product that looks the fullest.  Now the container with the least visual amount probably meets the regulatory requirements for the product but the consumer is left with the feeling the lower volume product is under filled, rather than the others being overfilled – a perceived value issue.  The overfilled containers are giving away product and that has a cost associated to it.

In addition to the overfill raw material costs for a product a second consideration in these times of high fuel prices is the surcharge for shipping overfilled products.

How about a “Golden” example of doing it right.  What if had your favorite hamburger, say a Big Mac and it was different each time you ordered one. It may not be your favorite after a few of those experiences.  Well, I have spent time with McDonald’s store owners and have asked them – how do you make a product the same and meet customer expectations when that customer may visit different locations each time they buy a Big Mac.  Systems is how!  They use the same suppliers who must meet rigid specifications, they train their people to the same standards, maintain the look and feel of the stores to provide the same experience each time.  They constantly monitor and measure each and every detail to insure you get the same Big Mac each and every time.  They know that you expect to get the same result wherever you go and they work hard to meet your expectation because they are banking on it…a consistent brand is a big part of their success.

Quality Window is the tool to help you achieve low variation and run to optimum target.  First, this is a way of life – almost a cult following.  Once you start down this road, it will be what you do day in and day out.  It will be a process that you refine over time and it is what will ensure you continue to perform at a given level.  It is not something you stop doing because the problems you used to see seemed to have disappeared.  It is the reason that these problems do not come back.

Quality Window comes with a number of examples that will help you get started on this path.  The Process Monitoring example as well as the Fill Weight example help to demonstrate the principal.  What I would like to talk about is the work process that these types of applications support.

First, you need to identify the variables and grouping of variables that you need to monitor.  Groupings are things like Line specific, Product specific or Customer specific requirements or specifications.  For each of these you will set specifications, control and target limits to monitor these items.  These will be the limits you will measure against to understand how you are doing.

Next, you need to set things like sampling frequency, how often do you test these variables to maintain the level of control you require.  This is a whole science in itself but a simple rule is how long can you leave a variable un-monitored before it becomes a problem.  Experience, customer or regulatory requirements will help dictate this.

Setting alarm levels or rule violations is your next step.  The proper setting of Specification, Control and Target limits are important here.  Also the types of rules, like one sided limits where you do not care if the value is high only if it is low.

Another important component is User Help systems.  Quality Window has the ability to provide variable specific help if desired and this becomes a powerful tool for delivering help at a click of key – things like CBA’s Current Best Approaches so that knowledge and experience is shared across all applications, lines and shifts.

A Proven Methodology for a continuous improvement effort!

The steps to follow are: each screen mentioned are detailed in other Blog entries

  • Record the data – this is typically the Add data screen.  Data as entered will be displayed in colors based on the limits set for each variable.  This is the first visual presentation of the data for review.
  • Review the data collected – The Rule Violation Summary Screen will be presented automatically after each record is added to a Quality Window Application and a violation is detected.  Only variables that violate rules are displayed and this supports “if it ain’t broke don’t fix it” or in other terms you only see the problems that currently exist.  The Rule violations are prioritized in terms of importance – Specification limit rules are higher that Control Limit rules and so on.
  • The investigative process begins and if there is a User Help system included that would be my next stop.  This can guide users on typical causes for upsets and what to do next.
  • Next a review of the variables with the rule violation using the Control Chart Screen,  This muti-view screen provides a historical look back in time (control or run chart) a histogram to display the distribution of the data as well as summary statistics that include the highlighting of statistics that violate a specified level giving clues to the nature of the problem experienced.
  • The Relationship screen would be the next stop as it will provide you with a statistical display of variables that could affect the variable you are currently reviewing,  This is a very powerful tool for understanding the complex interaction of variables within a process.
  • The Comparison chart allows you to review two time frames for a variable or two separate variables to do before and after analysis.  This is very useful in determining if changes have had a positive or negative effect on a variable or process.
  • A quick report is also useful to give an overview of the overall process in a snap shot summary statistics view which includes the highlighting of statistics outside tolerances.
  • The final step is very important, at this point you have finished your investigation and now must take some action which could include taking a corrective action like making an adjustment or cleaning a part.  Just as important is identifying new variables that if monitored could have avoided this rule violation.  In the case of a new variable(s) being identified to be tested, you would use the QWAdminrapid change tool to add these variables to the application and start collecting data with the next sample taken,  It is that easy to adapt to change.

A Quality Window application is very easy to use and just as easy to change, and change is the reality of working on the shop floor.  Call it process monitoring, quality monitoring or a centerline application, the centerpiece that makes these applications easy to use and very successful is the methodology mentioned above.  The Rules Summary screen is the watch dog that ensures problems are highlighted in a timely fashion and the analytical screens provide an easy to use and intuitive way to understand what is going on in your process.  The ability to react to change so quickly is a huge advantage to using Quality Window and having it maintained within a department rather than getting on a priority list and waiting for the changes to be made.

The sample applications included with Quality Window give you a head start on getting going quickly with Quality Window.  The applications, located in the QW50 installation directory Busitech/QW50/Sample Applications directory, contain many additional features that I would encourage you to explore.


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