Seven Basic Quality tools documents

Definition of Quality Management -- it is a method for ensuring that all the activities necessary to design, develop and implement a product or service are effective and efficient with respect to the system and its performance. It is also a principle set by the company to endure the continuous advocacy of quality services and products, or the further improvement of it.

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Inspection is defined as “the process of measuring, examining, testing, gaging, or otherwise comparing the unit with the applicable requirements” (Suntag). This essential quality tool is used in every organization to ensure that the quality of their product is acceptable to the customer as well as the industry.  There are two primary purposes for inspection. These are to make sure the product conforms to specifications and to determine whether a non-conforming product is fit for use. In the following paragraphs, we will discuss the uses, strategies, and tools of inspection.

Organizations may use different strategies for inspection depending upon the type of process they use and the cost-effectiveness of using that strategy. Types of inspection include operator inspection, in-process inspection, tollgate inspection, automated inspection, 100 percent on-line inspection, and computer-aided inspection. Firms in the U.S. and Japan do not commonly use tollgate inspection because of the need to inspect 100 percent of the product at every station before moving on.

Operator inspection involves a trained operator at one or more workstations. This is the best position for inspecting a product given there is enough time between workstations to complete the task and the operator is sufficiently trained. The operator may also verify work done at previous stations.

In-process inspection is when an inspector patrols from station to station at given amounts of time to ensure that the inspection procedures are properly executed.  This type of inspection is desired when the product has a low defect rate, when operator inspection is not sufficient, or when there are new employees on the job.

            Tollgate inspection uses a sampling station at a fixed point within the process to evaluate the quality level of products produced in a given department before moving them on to the next. This type of inspection is used when there is a high defect rate or when there is a need to enforce quality levels between departments.

            Automated inspection is used where human inspection would not be possible or sufficient. Usually, automated inspection is used in mechanical or electronic industries. It is also used when more precision is needed in the process.    

            100 percent inspection is done in-process and involves separating the good products from the bad. Contrary to its name, not all of the defects are always caught since there may be multiple products flowing through the system at any one time. Therefore, some companies may inspect the product multiple times, in which case it is called 200 or 300 percent inspection.

            Computer-aided inspection (CAI) is the most modern form of inspection. It allows for 100 percent inspection at a relatively low cost and there is less chance of damage to the products because the products are not physically handled.

            The type and frequency of inspection can vary from firm to firm. A firm implements its desired degree of inspection until it meets predetermined standard of quality or the standard of the industry. Also, the best inspection strategy may change as new technologies are introduced. The tools used for inspection include acceptance sampling and control charts. Acceptance sampling occurs when a whole lot or shipment is rejected from examining a percentage of the lot. The exact percentage is up to the firm to decide. Control charts called x-bar and R charts take samples from a lot to measure a particular characteristic. If the samples fall within the upper and lower control limits then the whole lot is determined to be acceptable.  These charts also help to determine if the firm should implement more stringent standards for higher quality.             

            As you have seen, inspection is a very important part of the manufacturing and production process. It is essential to the success and productivity of an organization as well as cost-effective. Implementing inspection into every stage of the production process will prevent expensive costs from rework and returns. It can be used to inspect damages caused in-transit from one location to another, in checking that an order is correct and that it meets conformance specifications as well as many other uses. More information can be obtained about inspection from the reference given in the bibliography as well as on company websites.


Juran, Joseph M. and Frank M. Gryna. 1980. Quality Planning and Analysis. New York: McGraw-Hill, Inc.

Perigord, Michel. 1980. Achieving Total Quality Management: A Program for Action. Cambridge: Productivity Press.

Suntag, Charles. 1993. Inspection and Inspection Quality Management. Milwaukee: ASQC.

Hradesky, John L. 1995. Total Quality Management Handbook. New York: McGraw-Hill, Inc.

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