Thursday, September 25, 2008

Maintaining Documents and Records

Every key step or change in the project or quality control change needs to be documented so that the reason for any changes can be traced at a future date. The documentation serves as authorization for action and evidence that the change did occur.

Project or process documentation begins with the original concept plan. It then evolves into activity-based documentation in which there are a variety of possible documentation types.
  • Checklists - can be developed to ensure that documentation flows properly and that certain documents are retained for archival purposes. There should be a checklist for every major activity that needs to be completed before another can begin.
  • Control sheets - record the flow of key documentation and changes. Data on decisions, changes, and who made them, are recorded.
  • Sign-off sheets - are documents which verify that a particular stage to a project has been completed to the quality goals. Sign-off sheets record specific information about which activity has met the standard and when.
  • Approval forms - verify that permission was given to advance to the next stage in a tightly controlled project. They are somewhat similar to sign-off sheets.
  • Reviews - examine a process or stage of a project to ensure it has met the particular goals set out in the original plan or to other quality standards. Most reviews recommend changes of some sort.
  • Testing reports - are carried out by specialists such as laboratory technicians, programmers, and quality testers. Their language is quite technical, however the use of non-statistical and statistical techniques can aid understanding. Test reports can express if a change, or no change, is required.
  • Logbooks - record the movement of documentation and when certain activities occur. This ensures an orderly flow and if a problem arises, it can be examined to see when and even what was responsible. Logbooks in manufacturing often contain the data required for analysis.
  • Acceptance reports - indicate whether a project or product was done satisfactorily. If not acceptable, suggestions can be offered. It is similar to a sign off sheet, but with more detail.
In addition to these activity-based documents, various standards organizations may require you to maintain records verifying conformance to industry standards. These records may be in the form of:
  • inspection reports
  • test data
  • qualification reports
  • validation reports
  • survey and audit reports
  • material review reports
  • calibration data
  • quality-related cost reports.
Depending on the project, you may also need to save instructive documents such as:
  • drawings
  • specifications
  • inspection procedures
  • test routines
  • work instructions
  • control sheets
  • the quality manual
  • operational procedures/checklists
  • quality system procedures.
All records and documentation need to be clear, legible, dated (including revisions), identified, accessible, and stored to prevent deterioration or loss. These can be in the form of images, hard copy, CD-ROM, and electronic files. The quality management plan for the project or company should specify how long documents need to be kept and how they should be disposed of once out-dated.

The control of documentation depends on the process or project undertaken. Long duration projects may require documents and records to be archived at set intervals. Short duration projects may allow subordinates to retain documents until the end of the project and then they are stored. For most projects there should be some sort of post project review. The idea is that the record keeping can provide specific information to see if the various procedures work well. This is a function of quality assurance.

Documentation is often relegated to minor status in a project. Many people think once the key work is done, that there will be time later to catch up on the paperwork. However, in a proper project, documentation is designed into the process to ensure an orderly flow, without unnecessary paperwork. The preservation of data, decisions made, and the general plan and outline of the project are key to ensuring quality.

Sunday, September 21, 2008

Making Process Adjustments and Quality Improvements

Have you ever encountered a situation where something has gone wrong and you wondered what could have been done to prevent it? Process adjustments and quality improvements can address this issue.

Process adjustments
Process adjustments may be corrective or preventive. Corrective adjustments are taken after a problem has already been discovered. Preventive adjustments are taken beforehand to prevent problems from happening.

Some of the most common process adjustments are: rework, redesign, change of equipment, change of personnel, and change of process. To prevent problems from occurring, each process is analyzed to determine where things could go wrong. Preventive steps or processes are then planned into the various activities.

In extreme cases, a process problem may demand rework. Rework requires that the production lot or phase of a project be redone. Obviously, rework should be avoided if possible. However, rework can be planned out conceptually by having inspections, testing, and measuring at logical points in the project or process. This minimizes rework, restricting its use to occasions of absolute necessity.

Another possibility is that a process needs to be redesigned. Projects often have an experimental or trial phase that tests the functioning of an item. This process needs to be planned so that the time exists for redesign, and redesign work is minimized, especially at later stages.

The problem may be the equipment. It could be worn out, outdated or unable to perform to the new designs or specifications demanded of it. Equipment upgrades can be planned into the project or process at various stages. This ensures that the machinery does not wear out and that it will meet future specifications.

Sometimes the problem is with a worker or supervisor. Many employees become bored with their jobs. A worker, supervisor or inspector may not be working as hard as they should be. Perhaps not enough training has been given to employees who need it. Personality conflicts may also be an issue.

Frequent rotation of workers may be desired. Properly scheduling breaks, work hours, vacation, and an understandable promotion system can make a work force more energetic. Refresher training reminds workers of quality issues.

On occasion the process itself may be flawed. Due to employee inexperience, a one-time modification of the process may be required. Plant layouts may need to be updated, efficiency studies undertaken, or adoption of higher forms of technology may be necessary. Annual audits help managers to identify the need for efficiency studies, increased automation, or changes to the process requiring more or less inspection, or testing as appropriate.

Quality Improvements
Quality improvement can occur in two manners. The first and most desirable way is through planned inspections, or audits, of a project or product process. The changes are enacted through a change request. The change request is based upon a well-reasoned and thought out analysis. Unplanned improvement can also occur through corrective action. Too much rework can result in an audit which then decides if a process or procedure needs changing. A change request initiates the improvement.

Both of these methods can address short- and long-term problems to a project or a production process. Consistent and constant attention to quality control is required to remind everyone that quality control can happen at any time.

No one person is solely responsible for quality control. All employees are responsible for identifying potential problems. It should not just be left to the inspectors or quality assurance department to ensure a process is being performed correctly. Interaction is necessary between all the stakeholders in a process or project. This involves the workers, managers, inspectors, engineers, and even the client. No one person can make a change without consideration of all possibilities.

One way to ensure smooth communications between all the stakeholders is to hold frequent meetings of all levels of personnel. This is termed a Quality Circle. Meetings are held frequently where concerns are brought up, ideas discussed, and new methods introduced. The idea is that everyone becomes aware of the others' positions and responsibilities on each issue. Quality improvement ideas are often discussed.

Workers can suggest changes to a process, calibration, or material. They see and do the process on a daily basis. Their suggestions are often preventive in nature. They are also the first line of defense in defect identification.

Managers are responsible for ensuring that the right activities occur at the right time. They can coordinate training, ensure workers and inspectors are doing their jobs, and coordinate with the engineers and clients about problems or changes.

Quality assurance and control is the function of the inspectors. Changes in procedures or processes can be initiated by them or discussion on new methods needed when a problem is identified. Whenever possible, they should act preventively.

Engineers or designers are often asked to study the technical aspects of a problem. They can also suggest the need for a change in process or design based upon new concepts, methods, or technology.

Ultimately, the manager is responsible for change. However, each employee is responsible for understanding the changes and for implementing them. They must also ensure that feedback is accurately conveyed. A progressive attitude by all is required.

Problem identification and resolution takes time. A group may need to meet several times to adjust the process and develop quality improvement ideas. Regardless, process adjustment and quality improvement must be thought of as a continuous process. There is always room for improvement, and prevention is always cheaper than correction.

Friday, September 19, 2008

Deciding Whether to Accept or Reject Project Work

Have you ever done a project inspection only to find the result failed to meet its specifications? If so, you may have been forced to make a decision whether to accept or reject the result, whether it was a final product or some intermittent stage.

Acceptance decisions can occur at several levels of management. At the lowest, a worker or inspector sees a fault, and brings it to the attention of a supervisor. The fault could be in the material, the process, or the output. The supervisor or project manager must then decide if the product or project can proceed.

There are four types of acceptance decisions:
  • Go/No go - A product in an intermediate or final stage is inspected to determine if it can go to the next stage of processing. Go/No go acceptance is useful if a particular stage has a high rate of failure, or the next stage is an expensive step.
  • Conforms/Does not conform - Conforms/Does not conform acceptance means that an item meets either a single or a variety of specifications. It can fail even if it passes all but one criterion. This category of acceptance frequently uses specification ranges determined in part through statistical analysis.
  • Yes/No - Yes/No acceptance checks to see if project work meets certain criteria or checkpoints. Yes/No acceptance uses checklists to document that procedures and quality specifications have been met. The items on a Yes/No checklist may include: proper assembly, documentation, marking or packing.
  • Pass/Fail - Pass/Fail acceptance often occurs at the final stage in a process or project. Specifications are used as a basis for determining if the project or item meets a variety of minimal expectations.
If a product or project is acceptable at a given stage, it continues to the next stage. If it is unacceptable, it can be reworked or scrapped.

A project or product may be found unacceptable if standards or goals have not been met. Standards refer to quality issues outlined in government, association, industry, or company policies or project specifications. Failure to achieve those quality standards are grounds for immediate action.

Goals refer to a product or project not quite meeting the expectation as originally envisioned. For example, a product or project may meet less exacting commercial standards but not military standards. A more limited goal may have to be accepted or the project may have to be redesigned.

In any product or project, the acceptability is dependent on whether the customer finds that the results meet their needs. Failure to meet the customer's needs means redesign and rework or face the loss of the contract.

Shortcomings in quality may be acceptable if the price is too high for what was envisioned originally. Product or project redefinition may be required if the high standard is impossible. Project abandonment may also be considered.

It takes time to resolve a problem in a project or product. A less-than-perfect product may be acceptable in order to capture market share, or meet other deadlines. High quality products may receive more time to ensure customer satisfaction and repeat business.

Unacceptable work can be made acceptable through rework. Rework is the necessary work to bring a product or project back within specifications or standards. Rework is known as a compliance activity. The cost and time taken to do rework can cost more than doing it right the first time.

Therefore, rework should be considered a short-term solution. It is cheaper to carry out prevention techniques such as training, inspection of inputs, and frequent inspections of the process.

Rework can consist of remilling a machined part, repainting, reassembly, or replacement of a part or subassembly. In each case, only the work required to give the item or project a passing grade is completed.

Quality control may not always catch everything. However, once a fault is discovered, quality decisions need to be made on how widespread the problem is and the seriousness of the problem. If the product is produced as runs or lots it is easier to determine how widespread the problem is through sampling. Rework time, replacement and overtime costs, and loss of reputation if consumers reject the product, are all considerations facing management when encountering a quality problem.

Acceptance decisions are the key to quality control. Inspections and quality control analysis give the necessary information to make a logical decision by management. Rework should only occur if it is possible and cost and time effective.

Wednesday, September 17, 2008

An Introduction to Trend Analysis

In project management, it is useful to discern trends in the quality data to determine if the project is progressing according to quality expectations. Trend analysis is a technique that tells project managers whether quality goals are being achieved according to the quality management plan.

Trend analysis is a mathematical technique using statistical methods that provide an equation that best fits data in a scatter diagram. Scatter diagrams are simple X and Y axis diagrams with an independent variable, such as time, as the X axis, and the dependent variable as the Y axis. Trend analysis determines the best or most appropriate equation and measures the fit of the equation to the data. Trend analysis is also known as "curve fitting."

Fitting a curve is often done by the least squares method, a mathematical method in which the distance between the data points and a possible line is minimized over its length. This gives the most statistically accurate representation. These lines are often called "regression lines."

Trend analysis is a useful tool for cost and schedule performance, and quality control. The utility of the trend analysis is that it gives a clear and understandable indication of change caused by every incremental change of the independent variable. One of the more useful functions of trend analysis is predicting, or forecasting.

The different lines mean a variety of different things could have occurred in a process. Line and curve shapes indicate whether a process is behaving according to the quality control norms.
  • Lines of positive correlation - Lines of positive correlation indicate the desired value y is increasing. This is good if improvement is sought, but bad if the line continues past a specified value.
  • Lines of negative correlation - Negative correlation indicates y is decreasing. This is good if the tolerance of a process is coming closer to a desired value, but bad if that same value is exceeded.
  • No correlation - A diagram with no correlation means the data is inconsistent. The process is out of control, and immediate steps are necessary to bring the process under control.
  • No slope lines - A line with no slope means there is no change. This is indicative of a stable process.
  • Curvilinear line - Curvilinear lines indicate a cyclical process or a process decreasing or increasing at a non-uniform rate. Cyclical patterns indicate a possible worn out process. A curvilinear line indicates a complex relationship with the independent variable.
Of all the different lines, curved lines are the most difficult to make conclusions from because of their shape. Other statistical analysis must be used to determine at which point the objective value has been met or exceeded.

Trend analysis allows project managers and teams to predict a pattern and come up with a formula that accurately reflects a data set. As long as the appropriate quantity of data have been selected, accurate predictions can be made of a process. Trend analysis is also useful for determining at which point a quality concern may become an issue based on historic data. Trend analysis is often useful when used in conjunction with other tools and techniques.

Sunday, September 14, 2008

Using Control Charts to Identify Product Process Problems

Project managers use control charts to spot production process problems before they spin out of control. On a control chart, production data is plotted and analyzed for specific trends. Control charts are used more as a preventive measure rather than for detection or rejection of quality problems. This is extremely useful since it is cheaper to prevent mistakes than to correct them.

Control charts compare quality, cost, and time issues to an established norm. They indicate permissible behavior so that aberrations are easy to identify. Analysis of control charts determines whether a process is stable or whether corrective action needs to be taken.

Control charts can also help determine sources of variation. Variation is the range the observations fall around the process mean or average. Variation is different for every product or process since each has different characteristics.
  • Common cause variation - is random variation common to any process. This type of variation requires management decisions to change the basic processes. Common cause variation is caused by chance and requires no corrections.
  • Special cause variation - happens at the operational, or production, level. This variation is indicated by exceeding a control limit or a persistent trend towards the limit. Special causes exist when the variation in a process exceeds allowable standards. Corrective action is then required.
Variation is also categorized by time.
  • Short-term variation - can be caused by changes in suppliers or workers' performance.
  • Long-term variation - occurs in cases of tool wear, environmental changes, or increased administrative control.
There are two types of control charts classified by the type of data they collect. Variable control charts are used with continuous data in which all numerical values are possible. Variable charts are useful when measurements from a process are variable such as diameters, electrical output, or chemical concentrations.

Attribute control charts are used with discrete data, or when data can only have a certain value, or range, such as "1" for "yes" and "2" for "no" in a conformance test. Attribute charts analyze data such as conforming/non-conforming, pass/fail, go/no go, or yes/no measurements.

The use of these various charts depends on what type of quality measurement is desired. The most common type is the X bar chart, or process average chart.

Limits on a control chart are often called the three-sigma limit because most companies operate within the 3 sigma limit. In a normal distribution, 99.73 percent of the measurements lie within X bar ± 3s, or within the UCL and LCL. Some companies now employ a six-sigma limit in their quality control. This allows only 2 defects per billion. This exactness in quality is so expensive that it is only possible over very large production runs.

The high figure indicates a high degree of variation because more of the observations fall away from the average. Therefore, the taller the curve shape, or the bell curve, the lower the standard deviation will be.

Control charts can be interpreted in many ways depending on their patterns and line shifts. Experience is the greatest aid to understanding a chart. Control charts tell when to look for trouble but not where the cause lies. Control charts also indicate when to leave a process alone. Variation can be unnecessarily introduced by an operator trying to fine-tune a machine to near perfection, when the control chart indicates the operator could leave the process alone. Charts are interpreted by runs, trends, periodicity, and hugging.

Quality control inspectors also use the Rule of Seven to determine if a process is out of control. If seven or more consecutive observations are found to be on one side of the mean, then it is out of control. The reason it is said to be out of control is that there is only a 1.56 percent statistical chance of random variation that the run of seven would fall on one side of the mean.

One of the most useful quality control tasks is ensuring a process is in control, by identifying the existence of a problem. Control charts are a valuable tool in determining whether or not a project or process is in control. To be able to read control charts, you need to be familiar with the different control chart types and their components, and the various methods of interpretation.

Friday, September 12, 2008

An Introduction to Pareto Diagrams

Do you need a simple chart to convey the idea that quality corrective action is required? Pareto diagrams offer an effective, illustrative, and analytical tool for identifying quality problems.

A Pareto diagram is a modified histogram performance report. It receives its information from work results such as data figures, repair data, maintenance figures, or scrap rates.

Instead of grouping results by intervals as in histograms, Pareto diagrams lump similar quality defects together in order to identify the most common errors for corrective action. This is based upon the 80/20 rule where 80 percent of the defects are caused by 20 percent of the problems. Pareto diagrams are useful for measuring machine output and time reliant processes. There are three uses and types of Pareto diagrams.
  • Basic Pareto analysis - A basic Pareto analysis identifies the key contributors to the quality problem as a single diagram, with a percentage line showing each category as a portion of the cumulative total. The basic Pareto diagram identifies the most common problems.
  • Comparative Pareto analysis - A comparative Pareto analysis looks at a problem as a "before and after" comparison, using two Pareto diagrams. These diagrams show the change in the number of problems identified for each problem category.
  • Weighted Pareto analysis - Weighted Pareto analysis gives significance to unapparent factors such as cost, time, or criticality.
Once a Pareto diagram is constructed, the key defect areas become obvious, so you can reduce these defects to a more acceptable level. Then, after implementing corrective action, a new Pareto diagram may be constructed as a comparison to show that the key defects were greatly reduced.

Pareto diagrams are an extremely useful tool in quality decision making. The diagrams make it clear what quality changes need to be made and whether the remedy was effective. Keep in mind that Pareto diagrams do not identify causes, only problems, so other analytical methods may be required to gain further insight into the problem.

Wednesday, September 10, 2008

Constructing Cause-and-effect Diagrams

Have you ever had a quality problem that couldn't be quantified through the use of statistics? The relationship between a problem's effect and its cause is sometimes obscure. To solve the problem, you may need to examine the entire process, identifying all the potential problem sources before you can determine the root cause. When visually displayed, this problem-identification process is called cause-and-effect diagramming.

Cause-and-effect diagrams are also known as "wishbone" or "fish" diagrams because of their shape. A cause-and-effect diagram has a central "back bone" with "ribs" branching off. The process used to create the diagram is known as flowcharting.

Cause-and-effect analysis is frequently completed by a team since specialists in many areas or departments may be required to provide input into their part of the process. During a project meeting or conference, the project team will construct the diagram, starting with the problem and working backward to the beginning of the project or process.

In cause-and-effect diagramming, there are three possible methods for identifying causes:
  1. the random method
  2. the systematic method
  3. the process analysis method
The random method, during which team members randomly cite problems and probable causes, is a somewhat haphazard approach and may not identify all problem categories. However, it is useful as a general trouble-shooting technique and can help get the group in problem-solving mode.
The other two methods, systematic and process analysis, are more structured and rational in the identification of causes. These are used mostly by engineers and technicians.

The systematic method focuses analysis on one category at a time. Each category is examined in descending order of importance after the primary one is addressed.

The process analysis method looks at a production process identifying each sequential step, and the categories and causes for each step, one at a time.

When the cause-and-effect diagram has been constructed, the team or project manager can then suggest changes to the potential problem-causing areas. A series of experiments or additional statistical analysis may be necessary to determine the primary or root cause of a given problem.

The next step is to decide what corrective action is necessary. In the process of identifying the problem, the team suggests the desired outcome. By turning the diagram around, you can determine what impact the desired outcome will have on each of the listed categories and causes. In some cases you may find corrective action is required in one or all of the categories.

A machine in a process may require finer adjustment or even replacement if worn out. A newer machine may offer a leap in technology that may eliminate present quality control problems through greater automation or internal computer control processes.

The production or process method may require fine tuning, involving additional substeps before completion of a task. The layout of a process may also need reorganizing. Duties and responsibilities may need increased emphasis.

Stricter inspection and handling of raw materials may be necessary to ensure that they are of high standard. Improved selection of raw materials may also be required.

Changes to the measurement process may be necessary, such as more accurate measurements, increased frequency of inspection, and introduction of new statistical methods for analysis.

Perhaps current personnel are inadequately trained in both their job and in quality control. Upgrading job skills may be necessary. It is also possible that declining quality is due to poor work habits or boredom with the job.

Once the root cause of the problem has been identified and the effects of the desired outcome on other areas of the project have been studied, appropriate corrective action is taken. At this point, change requests are processed and safeguards set in place to prevent future recurrences.

Even when a problem has multiple sources, you will find cause-and-effect diagrams are invaluable in pinpointing them all. Flowcharting with cause-and-effect diagrams is an effective way to conceptualize causes to a problem in a project or process. Once flowcharted, the problem can be further analyzed using other analytical tools. Ultimately, corrective action and protective safeguards are applied to solve the problem and prevent future recurrences.

Monday, September 8, 2008

Statistical Sampling Methods for Project Quality Control

Statistical sampling is a way of identifying the quality of a service or product when it is impractical or too expensive to examine each item. Effective sampling is based on statistical probability theory which identifies the probability of error for a sample size. Using standard deviation and variance calculations, control charts can be constructed, which accurately predict the likelihood of a sample being representative of a population or lot size.

To be accurate, the sample size must be "representative" and "valid." Representative means that enough good and bad items must be included in the sample, so that it portrays the lot it is drawn from accurately. Validity is the measure, whereby the method of testing and the attributes measured are a true indication of what needs to be measured.

Key issues for ensuring accuracy are the proper determination of the sample size and the rejection level acceptable within the sample. Sampling methods include acceptance sample, attributes sampling, special attributes sampling, and variable sampling.
  • acceptance sampling
    Acceptance sampling tests selected items against an agreed upon list of necessary criteria. The inspection can be conducted in a variety of ways including electronic, stress testing, sample destruction, reaction testing, and temperature testing.

    It is more convenient to conduct acceptance sampling with lots in a production run. This reduces overall costs by making the sample sizes smaller and more manageable. If a quality problem is discovered, it is easier to track down the lot. It is also cheaper to rework or throw out the lot. Lots are often naturally created by factors such as shift changes, raw material lot sizes, handling or packaging sizes, or shipment sizes. Random selection within the lot is also important to ensure sample validity.
  • attributes sampling
    After the acceptance sampling method has been chosen, attributes sampling defines what exactly will be measured for quality control. This is often based upon past sample failure experience or customer feedback. The quality inspector merely checks the individual sample against the quality criteria. The attribute is measured by a simple "yes" or "no" that the item is acceptable. This method is often used in inspecting for size, color, finishing, marking, and packing. Data is recorded on a simple checklist sheet.

    The use of attributes sampling has some advantages and disadvantages. Attributes testing is simpler and less expensive than inspection by variables. Recordkeeping is simplified by having one quality level for a group of like attributes. However, attributes sampling also requires a large sample size to determine the acceptability of the parent lot, which makes the process time consuming and expensive.
  • special attributes sampling
    Statisticians have various sampling methods that simplify the inspection process, reduce time and cost, yet still ensure accuracy in the inspection process. These methods are referred to as "special attributes sampling" and include continuous sampling, chain sampling, and skip-lot sampling.

    With continuous sampling, inspection occurs throughout production, like on an assembly line. This method is often used when storage facilities are inadequate or it is difficult to accumulate large lots for inspection.

    Chain sampling occurs when a product is produced as a lot for inclusion into another product. It is tested throughout the manufacturing process. This method is useful when sample sizes are small, and there is good quality history.

    Skip-lot sampling reduces inspection costs by inspecting certain lots. This increases the quality risk, therefore a history of high quality is a key consideration. This type of sampling is used after the maturation of a process.
  • variable sampling
    Variables sampling collects data on possible variable items. When the error rate exceeds a combined level for several of the variables, the lot is rejected. The sample is rated on a scale against such criteria as time, distance, weight, strength, or purity.

    Instead of being tested as "acceptable" or "unacceptable," the sample is compared against historic values to determine problems. Variable sampling is used when the quality characteristic is measurable or quantifiable.

    Variables sampling allows a quality control team to accomplish more in its inspection and analysis process. Causal links can be explored as well, helping to determine the root problem in a product, process, or sub-process.

    The advantages include more data to compare to quality conformance criteria. It also requires smaller sample sizes, reducing cost while ensuring high quality.

    The disadvantages are that the quality inspectors need more training and that more sophisticated analysis is required to determine quality conformance.

    Acceptance and attributes testing can be tested separately or together. An item can be tested for one or several attributes and whether it achieves the desired specifications. Variables sampling is a more complex process requiring considerable thought in not only what is measured, but how it will be analyzed.
Any of the above sampling techniques can use special attributes testing to reduce the time spent sampling. In practice, many companies use all four sampling techniques together to ensure the highest possible quality control.

No matter what kind of sampling plan you choose, all require a sample of a particular size to ensure confidence in the results. The sample must be cost effective to conduct and accurate according to probability and acceptance theory. Sample sizes can be determined from the operating characteristic curve. The curve represents the historic results for a particular process and operating conditions. The curves change shape depending on the size of the sample. Formulas can be used to represent the diagram.

A major tire manufacturing company installed a new tire molding machine. A trial production run tested if the tires made with the new machinery were as strong as the old ones. In a production run of 10,000 tires, only one failed in a sample installation test of 100 tires. To confirm the accuracy of the test, two more test lots were produced with the same results. Since the old process experienced 1.5 failures per 100, this machine represented an improvement and the sample size continued to be valid.

Sampling techniques help ensure quality while controlling inspection costs. It is key that the proper kind of sampling is carried out to obtain the desired results. This ensures the sample will be accurate and valid. The proper determination of the sample size is also important. Representative is the other key consideration. Proper sampling techniques ensure other analysis methods are reliable indications of reality.

Saturday, September 6, 2008

How Inspections Aid in Project Quality Control

Most companies receive complaints about their products or services at some time. Since this is a common event, you should learn more about how inspections can help you produce superior goods and provide better services.

Inspection forms the backbone of quality control. Without inspection, identification of problems is impossible. This can have severe ramifications for the client-producer relationship. All projects or processes can be inspected using subjective or objective criteria for weaknesses in conformance to standards. Remember, the role of inspection is to ensure results meet specifications.

Quality control is based on a plan and work results. The work results come from the mandated inspection process. Inspection activities consist of measuring, examining and testing to ensure conformance.
  • Measuring - Most products or projects require acceptance inspection against specific physical requirements, such as dimensions. Processes often have ongoing measurements of critical criteria such as pressures. The goal is to ensure machines are calibrated properly.
  • Examining - Most products or projects require examinations to determine acceptability to a set standard or criteria. This can involve measuring or examination of more subjective criteria, such as appearance.
  • Testing - Inspection testing requires that the project or product be tested to ensure conformance. This can be done at the end, at different stages or as a continual activity. Testing is often necessary to check that a new technology, process or method will meet quality expectations.
In the production of a computer, various measurements, tests and examinations are made. Measurements are made on individual parts and subcomponents, such as the thickness of circuit board circuitry. Tests can then be run on these parts or subcomponents to ensure they work. Lastly, examinations can be made to ensure subcomponents and the final product were assembled correctly.
The quality management plan should indicate what control system is needed for inspection, measuring, or testing. The plan should give information on:
  • what test equipment is to be used
  • the method of test equipment calibration
  • the method of recording test equipment calibration status
  • the documentation of calibration information to determine when equipment is out of calibration
Inspections are not random affairs. The quality management plan helps determine when inspections should occur. Inspections occur at the moment at which it is most appropriate to ensure achievement of quality goals. This is a balance between just enough quality and the high cost of continuous inspection of all aspects of a project or a product.
Inspections after a single activity are the most rigorous of inspection processes. This method ensures each step in a process is compared to the desired goal. This is most often used in highly regulated industries that require tight tolerances, such as electronics.

Inspections at each stage ensure that a project or product is conforming to the specifications before more work is done. This prevents work being done on a flawed item, eliminating rework and waste. This is often seen in the construction and metal-working industries.

Most projects or products require a final inspection before shipment or acceptance by the customer or client. This ensures that all other inspections were successful. Some simplistic products or projects may not require inspection until completion.

The quality management plan is key to developing an effective inspection or testing regime. The plan needs to indicate relevant inspections or tests needed for a project to proceed to the next level, or be ready for client acceptance. The plan can give the following information regarding inspections and testing:
  • how suppliers verify subcontractor products
  • where each inspection/test is in the process
  • what characteristics, criteria, and techniques are required
  • where the client needs to verify the product
  • where regulatory verification is necessary
  • where third party testing, verification, validation, or certification is needed
During the production of a book, whether it be a novel or a textbook, various inspections and tests occur. The objective is to produce a written work that is free of factual and grammatical errors, formatted properly, illustrated correctly, logically laid out, and has a sense of coherent style.
After the author has written each chapter, style, logic, coherence, and general grammar and spelling are checked. After each chapter is submitted to the publisher, an editor checks for style, logic, coherence, and general grammar and spelling. Once the complete manuscript is finished, a variety of people look at it. The editor again examines for style, content and logic. A proofreader comments on grammar, punctuation and spelling.

After the content has been approved, the printing occurs. Author's proofs are then checked by the author, the editor, and copy proofreaders for any last minute errors in layout and formatting, including illustrations, before the final print run.

Inspections are also called "reviews," "product reviews," "audits" and "walk-throughs." It depends on the industry, the type of process or project and the purpose of the particular inspection. These terms can have quite narrow and specific meanings.

For example, an audit can mean different things. In a firm, an accounting audit inspects the books to ensure proper procedures and bookkeeping techniques were employed. A personal income tax audit accepts or rejects entries on your taxes based on income tax laws. A quality audit does not seek to inspect any product, but rather inspects the process of quality control to ensure the methods, measurements and people are being effectively used.

Inspection is a key component of the quality control process. Acceptance and rejection of poor quality work relies on inspections. Inspection results also provide the data used in statistical analysis methods.

Thursday, September 4, 2008

Using Work Results for Project Quality Control

Have you ever had a quality plan, but wondered how the plan provided quality control information that could be used for analysis? The quality plan has reporting procedures and feedback that provide this information. This information is called work results. The two most common work results are performance reports and change requests. Each will be examined in turn.

Performance reports
Performance reports provide data that can be turned into various visual charts for analysis. Three of the most useful activities that performance reports measure are:
  • schedule adherence
  • cost adherence
  • quality standards adherence.
In performance reporting, the simpler the visual projection of the data, the better. This makes it easier to understand the requirement for action. Four of the most common performance reports are: Gantt charts, S-Curves, histograms, and tables.
In histograms, data is shown as a vertical bar graph. This illustrates major problem categories. It forms the basis for control charts and Pareto diagrams.

Tables are often used to convey more complex data in its raw data form. Tables can convey observational data.

Performance reports can have a direct impact on quality management. Simple visual images can easily emphasize the need for immediate change. They can also indicate the project plan is working well.

A project manager for a microchip project submitted a weekly performance report after a difficult week. The visual report showed that most of the department's problems were coding errors. This indicated that changes were needed to prevent errors from reaching the final product. The project manager will have to look into this problem in more detail.

Change requests
Almost every process or project encounters some difficulty that requires a change in the conditions of the project such as time, cost, or quality objectives. Project managers may request additional time or money to ensure the project meets its original definition and expectations for quality.

Change requests, another form of work results, ask for the alteration to the project's objectives or quality. This can occur if the product is urgently required or additional expenses for quality will not result in increased profits or sales.

Change requests can also require alterations to quality methodology. Changes in the handling of data used to measure the project, the measurement process and techniques of data collection, or the evaluation of data, can be requested.

The handling of data may change in its method of collection, depth of detail, or type of data. For example, a company introducing new machinery may need to develop new measurements to reflect the change in machinery or technology.

Changes to the process or techniques of data collection are meant to ensure reliability, consistency, standardization, review, timeliness and rapid access to data. For example, a company may adopt an advanced database to aid inputting and calculations.

Change requests can also require new methods of analysis and improvements to the quality of data. For example, a manufacturing company using new equipment may want more precise data and more sophisticated analysis.

The value of the work results in the form of performance reports and change requests lies in their identification of a potential problem. The data these results provide points the way for more in-depth analytical treatment.

Monday, September 1, 2008

What Makes a Quality Management Plan Effective?

Have you ever had a problem that required implementing quality control methods, but you didn't know where to start? Proper project development requires a quality management plan to ensure that time and cost objectives and standards are met.

Depending on the needs of the project, a quality management plan can be formal or informal, detailed or broad. The best plans address the three aspects of quality—quality control, quality assurance, and quality improvement—and feature operational definitions as well as any procedures and standards.

Quality control, quality assurance and quality improvement
To provide direction and focus for project plan development, your plan should include details about quality control, quality assurance, and quality improvement measures.
  • Quality Control - monitors products for conformance to the quality standards and identifies ways to eliminate substandard work or failures. It requires detailed instructions based on the operational definitions, or measurements, for the project.
  • Quality Assurance - audits the organizational structures, responsibilities, procedures and processes of a project to ensure that the quality plan is providing effective feedback.
  • Quality Improvement - is the outcome of the quality assurance and quality control processes. A design experiment may be required to determine if there are new operating norms or if the new procedures will work. It may prevent re-occurrences of quality issues.
Operational definitions
Next, your plan must define what needs to be measured. Before the plan can be fully developed, the following operational definitions need to be identified:
  • What quality aspects will be measured?
  • How will each quality aspect be measured?
  • When will each quality aspect be measured?
Defining what needs to be measured can be the hardest part of the operational definition process. The governing rule should be to measure anything that can be variable in nature, whether the item to be measured is a human, a machine, a product, a procedure or process, or the environment.

Most final products require some sort of measurement to ensure conformance to subjective and objective standards. Subjective standards are difficult to measure. How exactly do you measure the aesthetic appeal of flowers? Objective standards require detailed measurements including destruction testing.

Forms can be developed to record objective and subjective measurements. Objective standards include strength, time, cost and measurement criteria. These need explicit data requiring detailed inspection processes and forms. Subjective standards, such as aesthetic standards, are most often measured using checklists with comment sections.

Determining how often to measure quality is another aspect of the operational definition process. Some of the most obvious times to test quality are:
  • upon delivery of raw materials - This determines if the supplier is meeting your standards. Items should also be inspected after prolonged storage, especially if they are environmentally or corrosion sensitive. Not every item needs to be inspected. Sampling techniques can be used.
  • at end of major stages in a process - It is often cost effective to inspect at the end of a sub- process to ensure substandard material does not progress further. This prevents wasted time, materials, and expensive rework procedures.
  • upon changes in operating conditions - An appropriate time to measure is after changes to procedures, processes, machinery settings and human operators. This can take place at different intervals: every few minutes, hourly, each shift, weekly, monthly, or yearly. The time sensitivity of the process determines the frequency.
  • upon completion of job lots - Many products are often produced in lots, partly as a function of the inputs process, but also as a function of testing and tracking of outputs. It is cheaper to throw out a small lot than an entire day's production run.
Ultimately, deciding when and how often to measure quality is a cost versus quality issue. Every item or stage of a project could be inspected, but the inspection costs may outweigh the final value.

Procedures and standards
The final component of a sound quality management plan involves procedures and checklists. Quality processes and standards should become routine and may be taught and enforced through procedures in the form of checklists.

Checklists confirm whether quality control standards have been followed. They can be instructive by outlining what needs to be done by saying, "Do Y." Process checklists also ensure certain tasks have been done by asking, "Has X been completed?" In some processes or projects, inspection checklists can gather data on the number of times tasks have or have not been performed adequately.

Checklists ensure that process steps are not overlooked or forgotten. They also ensure that the product does not advance to the next process before necessary tasks are done. This prevents costly rework if changes are required.

In some cases, companies perform work to certain external standards as expressed in governmental or association regulations or guidelines. If this is the case with your project, you can develop checklists which include standards.

Project quality is only as good as the quality management plan. To ensure project quality, the plan must be well thought out and rehearsed. Project quality can be ensured by a complete understanding of: quality control, quality assurance and quality improvement; operational definitions; and checklists and standards.