Nonconforming Product

ISO 9001 section 8.3 Control of nonconforming product states: “The organization shall ensure that product which does not conform to product requirements is identified and controlled to prevent its unintended use or delivery.”  The standard requires that a specific procedure be written that describes how nonconforming product is controlled.

Simply put, the standard is saying: Don’t mix the good stuff with the bad stuff.  Defective material should be placed in an area specifically designated for nonconforming product.  That area should be segregated from good product and specifically labeled as nonconforming product.

The product placed in that area must be labeled, and its nonconformances identified.  It is common for organizations to generate a report that identifies and describes the defective product.  These reports go by many names such as Discrepant Material Report (DMR), Nonconformance Report (NCR), etc.  They typically identify the product, the discrepancy or discrepancies, and the number of pieces involved.  The form is also used to identify the actions taken, who authorized the actions, and what the final disposition of the material was.  The standard allows the following actions:

• Rework the product to specification
• Use as is (“authorizing its use, release or acceptance under concession”)
• Scrap
• Re-grade for some other purpose

My personal opinion is that ‘Use as is’ should be avoided if at all possible.  It has the following problems:

• An inferior product is gets shipped to customers
• A message is sent to employees that defects are acceptable

When product is reworked, it must be inspected for the defect originally identified. 

The discrepancy report, indicating the actions taken and the final disposition is a record which must be maintained.  Periodically records of nonconforming product should be analyzed.  Analysis might identify possible preventive actions that could reduce nonconformances in the future.

For more information visit www.rosehillsystems.com .

Supplier Evaluations

ISO 9001 section 7.4.1 states: “The organization shall evaluate and select suppliers based on their ability to supply product in accordance with the organization’s requirements.  Criteria for selection, evaluation and re-evaluation shall be established.  Records of the results of evaluations … shall be maintained.”

Some customers use site visits to assess the capabilities of the supplier, but ISO 9001 does not specifically require this practice.  Most customers send potential suppliers a self-assessment questionnaire.  Self-assessment questionnaires can be simple or complicated to complete.  Be aware that the likelihood of receiving a response to a questionnaire is inversely proportional to the questionnaire’s complexity.

I’m not in favor of complicated multi-page questionnaires in most cases.  If the organization intends to place a small order with a supplier it is not likely to use often, it is unlikely that a complex questionnaire will be returned in a timely manner, if it is returned at all.  A simple, short questionnaire is more likely to be completed and returned.

If the supplier is to be a key supplier with a significant business opportunity, and a likely long term business arrangement, it may be better to visit the supplier and complete a complex questionnaire yourself in an on-site audit.  Meeting the players creates a better, more lasting relationship with the individuals involved.  These relationships make problem solving over the phone or by e-mail more likely to be successful.   As to what questions to ask, Govind Ramu presents an interesting perspective, in the Expert Answers section of   Quality Progress March, 2013 where he addresses questions to ask and not to ask a supplier.

Consider establishing (and documenting) multiple criteria any of which will qualify the supplier.  Examples might be:

·         ISO 9001 certified

·         Over one year experience with the supplier with few product rejections

·         Franchised supplier (for distributors)

As you collect supplier qualification data, consider storing the responses in a database.  The database facilitates contacting suppliers when quality problems arise and provides a tool for re-evaluating the supplier.  I recommend contacting the supplier near the time when his certification expires, and if it is not certified, annually.  A database can facilitate and automate this work.

Key suppliers, those suppliers who get most of your business, should be rated by some rating system routinely.  The ratings should be fed back to the supplier.  Examples of such ratings might be:

·         On time delivery percentage

·         Number of lots rejected divided by the number of lots received.

·         A multiple of the two above.

For an example of a simple questionnaire visit www.rosehillsystems.com and click on Tools.

Preventive Action

Preventive Action

Many get confused with corrective and preventive actions.  While corrective action deals with existing nonconformances (defects), preventive actions deal with nonconformities that haven’t occurred, but might occur in the future. 

In section 8.5.3 Preventive Action, ISO 9001 states “The organization shall determine action to eliminate the causes of potential nonconformities in order to prevent their occurrence.”  Potential problems are usually identified from the analysis of metrics, or from audits.

For example, an organization has a metric for on time delivery, and will take corrective action when delivery falls below 95% on time.  The metric is above the limit, but examination of the metric chart shows that on time delivery has decreased each month for the past 5 months.  A corrective action is inappropriate because the metric hasn’t fallen below the requirement (95%).  In this case, preventive action is more appropriate.

Whereas corrective action requires that action be taken, preventive action does not.  Consider a control chart for a machine tool.  The chart indicates that the tool is wearing and may need to be replaced soon.  Do we change the tool now or wait until the control limit is exceeded?  An economic analysis might suggest that we wait for the control limit to be exceeded because the cost of the tool is high or the cost of lost production is high.   The customer may be in critical need of the product and we can’t afford to shut down the machine now.  A decision to continue production would close the preventive action.

 A decision to take action would allow the machine tool to continue operation while a plan is developed for implementing a replacement.  In contrast, if this were a corrective action, the tool would be shut down until a replacement is available.

Once the decision to take preventive action has been made, the process becomes very similar to corrective action.  An action is selected, usually by a team.  A plan is developed to implement the preventive action selected, and the implemented action is monitored for effectiveness.

Some organizations use one form for both preventive and corrective actions.  In the case of a preventive action, there is no evidence of nonconformance, and there is no containment plan, since a nonconformance has not occurred.  Root cause analysis still occurs because there may be many choices of actions to take.

When the action(s) have been identified, a plan for implementation is developed.

My steps of preventive action look like this:

1.       Problem statement

a.       State the requirement

b.      State the evidence of potential nonconformance

2.       Root cause analysis

3.       Preventive action plan

a.       What action(s) will be taken?  NOTE: The plan might be to do nothing.

b.      When will they be implemented?

4.       Follow Up

a.       Were the actions taken effective?

In contrast, my 5 steps of corrective (See my August 2012 blog) are

1.       Problem Statement

a.       State the requirement

b.      State the nonconformance

c.       State the objective evidence of the nonconformance

2.       Containment Plan

a.       When did the problem start?

b.      What are we doing to control the bleeding while we are looking for a solution ( short term fix)

3.       Root Cause Analysis

4.       Corrective Action Plan

a.       What will be done to eliminate the root cause(s)?

b.      When will they be implemented?

5.       Follow Up

a.       Was the implemented corrective action effective?

b.      Was the short term fix removed?

 

For more information visit www.rosehillsystems.com

Production Control

ISO 9001 section 7.5.1 states:  “The organization shall plan and carry out production and service provision under controlled conditions.”  It goes on to state that controlled conditions means availability of product specifications, work instructions, equipment, and test equipment etc.

In an audit I was conducting recently, I came across a work instruction that instructed the technician to ‘use the custom jig.’  This raises the question:  Does ‘controlled conditions’ mean that jigs and fixtures should be identified and controlled?  It’s an important question from the auditor’s point of view.  If the fixtures are not controlled, should I write a corrective action?

To me, control means the same thing for a tool that it means for a document or  inspection equipment.   It should be identified, it should have a revision, changes to it should be approved prior to issue, and it should be inspected periodically to assure it is viable for use.

I raised the question of controlled tools with other quality professionals, and they all seemed to think the standard is moot on this point.  They all agreed that it makes prudent sense though.  Other standards such as AS9100 (the aerospace equivalent of ISO 9001) clearly state the requirement for tool and jig control.

Consider the potential problems:

·         A fixture used in production wears out over time and must be replaced.  Without a drawing, how do we make a new one that works the same as the last one?

·       The fabricator of the fixture leaves the company, or worse, we need to use the tribal knowledge of the person who made it to make another (assuming he or she remembers how).

·         A technician trainee doesn’t know what ‘use the custom jig’ means and doesn’t use the one we’ve fabricated for the purpose.

The standard leaves many things to interpretation by the external auditor.  Regardless of what the standard says, or how it is interpreted, be sure to document all production tooling with a tool number or other identifier, revision level, and a controlled drawing.  Inspect the tooling periodically to assure it has not worn to the point where it should be replaced.  It may make your ISO 9001 implementation a little easier.

For more information go to www.rosehillsystems.com

On Inspection

ISO 9001 section 8.2.4 states “The organization shall monitor and measure the characteristics of the product to verify that product requirements have been met.”   The standard goes on to say “Evidence of conformity with the acceptance criteria shall be maintained.”  It fails to point out though that quality cannot be inspected into the product.

Many organizations fail to achieve high quality, because they rely on inspection in the belief that they can inspect quality into the product.  Point 3 of Edward Deming’s 14 points states “Cease dependence on inspection to achieve quality.  Eliminate the need for inspection on a mass basis by building quality into the product in the first place.”  Phillip Crosby’s second absolute of quality says it differently: “The way to cause quality is through prevention not appraisal [inspection]”.

For a good example of what can happen when inspection is used as the only means of assuring quality read Austin, A L (2013) “Failure of Inspection The consequences of layering on quality checks” Quality Progress, January 2013.

In an audit I performed recently, the customer was inspecting welds using dye penetrant testing.  I issued a corrective action because no evidence that the tests had been performed was available.  The test reports didn’t include a place for the technician to indicate that the testing had been performed.  When inspection is performed assure that the results of inspection are recorded. 

Keep in mind that even 100% inspection is not 100% effective.  Inspectors make mistakes too.  Focus on mistake proofing production processes and designing quality into the product, not inspecting quality into the product.  Inspect when you must.  Select inspection points to occur just before high cost processes occur.  This assures that the product conforms to requirements before high cost is added to the product.  When you inspect assure that the results of inspection are recorded.

For more information go to www.rosehillsystems.com

The Case for Quality

ISO 9001 section 0.1 states: “The adoption of a quality management system should be a strategic decision of an organization.”  While ISO 9001 is the most widely adopted quality management system (QMS) standard in the world, many companies attach little or no importance to a well-designed QMS.

A recent article: Stauffer, R, Owens, D. “Lasting Impression: Quality management’s positive impact on the economy” Quality Progress, November 2012 makes the economic case for a QMS implementation, asking the question: “Does quality have a payoff?”

The authors reference the study “The Contribution of Quality Management to the UK Economy”, jointly commissioned by the Chartered Management Institute (CMI) and the Chartered Quality Institute (CQI). 

The study, researched and written by the Center for Economic and Business Research (CEBR), conducted a review of relevant business and economic literature, developed 18 case studies from various business and public service sectors, and surveyed 120 organizations.  From the literature research it concluded that an effective QMS resulted in:

·         Upward pressure on stock prices while unsuccessful quality management systems had the opposite effect.

·         Enhanced customer and employee satisfaction and retention.

·         Reduced costs.

·         Improvement in key financial performance metrics.

·         Greater focus on customer satisfaction.

From the organizations surveyed the CEBR found:

·         On average costs were reduced by 4.8%.

·         More than 93% agreed that the QMS was a significant contributor to success.

·         95% agreed that the QMS contributes to customer retention and satisfaction.

·         83% thought that the QMS provides consistent improvement and therefore higher productivity

·         83% agreed that without an effective QMS they could not justify pricing to customers.

The study examined key economic indicators in the UK for 2011.  The study determined that an effective QMS:

·         Contributed ₤86 billion ($135 billion) to GDP.

·         Contributed ₤8.4 billion ($13.1 billion) in corporate tax receipts.

·         Caused employment to be 1.43 million higher (4.94%) than it would otherwise have been.

The article makes a strong case for a well-designed QMS.  The results are likely transferrable to the US economy with similar results.

The benefits of an effective QMS take time to appear.  They do not happen overnight.  Commitment, involvement, and leadership from senior management are keys to success.

For assistance with ISO 9001 implementation see www.rosehillsystems.com

 

Acceptance Sampling

ISO 9001 section 8.2.4 says that the organization must monitor and measure the characteristics of the product in order to verify that the product meets requirements, but is silent on the methods to be applied to monitor and measure product characteristics.  The choice of inspection methods is left to the organization. 

Acceptance sampling is one such method.  Since it is not practical to inspect every item in a large batch, acceptance sampling allows you to infer batch quality by examining a random sample from the batch.  Statistically designed acceptance sampling plans, as a method of measuring product conformity, have been around since at least World War II.  Sampling plans like MIL-STD-105, authored by Harold F Dodge and others, have been in use for over 60 years.

Because not all items in the batch are examined, there are risks associated with statistical acceptance sampling.  Two risks are typically calculated:

·         The Acceptable Quality Level (AQL), also known as producer’s risk, is the percent defective that is likely to be accepted 95 % of the time.  There is a 5% chance that product of higher quality than the AQL will be rejected by the sampling plan.

·         The Lot Tolerance Percent Defective (LTPD), also known as consumer’s risk, is the percent defective that is likely to be accepted 10% of the time.  There is a 10% chance product as defective as the LTPD will be accepted by the sampling plan.

Each sampling plan has an associated operating characteristic curve (OC) which describes the probability of lot acceptance as a function of the lot’s percent defective.  The AQL and LTPD represent two points on the OC curve.  As the lot percent defective increases, the probability of accepting the lot based on the sampling plan that the OC curve represents decreases. 
In addition to the risks associated with acceptance sampling plans, there are some practical disadvantages:

·         While acceptance sampling greatly reduces the number of items inspected, other sampling methods such as statistical process control reduce inspection even further and provide process control feedback.

·         When a lot is rejected, we will know why the lot is rejected, but we will not know the root cause of the defect.  We will only know that the product is defective.  There is no control mechanism that will help us control the process the product comes from.

·         Acceptance sampling assumes random sampling, but in most cases the sample is stratified because the product is normally stored in boxes.  As such, it is possible that some product will never have a chance of being sampled and the sample will not be random.

·         Sampling plans based on AQL, LTPD, or AOQL (Average Outgoing Quality Limit) assume that a certain amount of defective material is acceptable.  This sends a message to employees and suppliers that some level of defectiveness is acceptable.  This is not the best message to send if the organization is trying to be a best in class producer.

Sampling plans can be designed by users, or selected from standards such as MIL-STD-105, now obsolete, or ANSI Z1.4 which implements the same plans.  A common pitfall suffered by users not familiar with sampling plan design is to design constant percentage sampling plans.  Avoid constant percentage sampling plans (a fixed percentage of the lot is sampled regardless of lot size).  For small lots, constant percentage sampling plans may not afford enough protection.  For large lots, an excessive amount of inspection will usually result, and the sampling plan will be over critical.

Consider a sampling plan that samples 10% of a lot.  For a 50 piece lot, a 5 piece sample will result in approximately a 1% AQL, but a 46% LTPD (a very weak sampling plan).  For a 5000 piece lot, a 500 piece sample will result in an AQL of .001% and the LTPD will be .46% - a plan unlikely to accept any lot.

While there are better ways to control production processes than acceptance sampling, acceptance sampling can be an effective method for a customer to protect itself from accepting defective purchased product.  Since the customer has no control over the manufacturing process, it is not important for it to understand what process variable caused defective material.  It need only know that the product is defective.  The customer is susceptible to stratified sampling, but accepts this disadvantage in favor of inspecting a small percentage of the entire batch.

For more information see www.rosehillsystems.com