Important Objectives Of Quality Control

Published Date: 02 Nov 2017

Any product offered to the market is for the purpose of fulfilling a utility, although a product has to offer a lot more than just satisfying a need; product has to provide quality to the customer. Modern customers are very demanding and requires a whole package of services and utilities than just a single product.

Quality is becoming one of a threshold requirement not only in the utilities it deliver but also in processes a business goes through during their activities. Total quality management and quality controls are two of the rising terminologies coming up as the requirement for quality has increased.

It would unfair to confine quality in few words as it is a broad term, and can be defined in many different ways by different people. Some define it as meeting customer requirements, some as exceeding it. Reliability and delight delivered is also considered to be as quality, as well as reaching zero defect to.

According to ISO 8402-1986 quality standard "quality is the totality of features and characteristics of a product or service that bears its ability to satisfy stated or implied needs."

Some of the definition of quality are:

Conformance to specifications measures whether the product or service meets the target and tolerance level determined. For instance, the specified dimensions for a part of machine may be specified by the engineer as 3.05 inches. It would be interpreted as the core dimension is 3.00 inches but it can vary from 2.95 inches-3.05 inches. Likewise, the time of waiting for room service might be 20 minutes, but there might be a tolerable delay of additional 10 minutes. The amount of light provided by a 60 watt light bulb can also be considered. If the bulb provides 50 watts it does not obey the specifications. As these examples illustrate, conformance to specification is directly quantifiable, though it may not be related to the buyer’s idea of quality.

Fitness for use emphasis on whether the product accomplishes its intended function or use.

For instance, a BMW and a Jeep Cherokee both meet a fitness for use specification if transportation is considered as the intended function. It can also be seen that fitness for use is a user based definition; it is proposed to meet the needs of a specific user group.

Value for price paid is explains quality as that consumers often use to evaluate product or service usefulness. This combines consumer criteria with economics; and also assumes that the definition of quality is price sensitive.

Consider, that consumer wish to sign up for a personal finance seminar and discovers that the same seminar is being taught at two different colleges at different tuition rates. If one takes the cheaper seminar, he/she will feel that you have received greater value for the price.

Support services provided is the quality of a product or service judged in terms of support services presented along with the core product. Quality not only confined to the product or service, it also applies to the consumers, processes, and organizational environment associated.

For instance, the quality of a school is judged by the quality of staff and course offerings, along with the efficiency and accuracy of processing paper work.

Further defined are the concept of Quality control and Total quality management:

Quality control:

Quality control are the set of procedures designed to ensure that the procedures and services performed are according to the desired quality standards; and to meets the requirement accordingly. QC is alike, but not indistinguishable from, quality assurance. Quality assurance are the set of procedures formulated to ensure that a product/service not yet developed meets specified requirements.

In order to implement a QC program;

A corporation first decides which standards the product or service must meet.

The extent of Quality Control activities are identified; consider the percentage of manufactured units to be verified from each batch.

Data from real world must be collected; such as, the percentage of units that fail and the results reported to an official.

Remedial action is decided and implemented; such as, defective units should be repaired/rejected and poor service repeated free of cost until the customer is satisfied. If unit failures or instances of poor service occur is high, a plan is formulated to increase the creation or service process and then the plan is implemented.

In the end, the QC procedure must be planned as continuing to ensure that corrective efforts have produced acceptable results and for immediately detecting recurrences or new instances of trouble.

Important objectives of quality control:

To bring a Reduction in per unit cost.

To achieve better Utilization of raw materials, human resource and money.

To take essential remedial steps to keep the Quality of product or facilities.

To attain greater consumer satisfaction by reducing client objections.

To locate and identify the processes faults in order to control.

To minimize scrap and waste.

Establishing Control Limits

Although it can be arbitrarily determine when to state a process not in control; Application of statistical principles are common to do so.

Suppose the mean of a variable has to be controlled, such as the size of piston rings. Assuming that the mean of the process does not change, the successive sample means will be distributed normally around the actual mean without going into details regarding the derivation of this formula, we also know (because of the approximate normal distribution of the means) that the distribution of sample means will have a standard deviation of Sigma over the square root of the sample size. It follows that approximately 95% of the sample means will fall within the limits of ± 1.96 * Sigma/Square Root.

The general principle for establishing control limits just described applies to all control charts. After deciding on the characteristic to be controlled, for example, for the standard deviation, the expected variability of the respective characteristic in samples of the size is estimated. Those estimates are then used to establish the control limits on the chart.

Common Types of Charts:

The types of charts are often classified according to the type of quality characteristic that they are supposed to monitor; there are quality control charts for variables and control charts for attributes. The following charts are constructed for controlling variables: https://cdn2.content.compendiumblog.com/uploads/user/458939f4-fe08-4dbc-b271-efca0f5a2682/6060c2db-f5d9-449b-abe2-68eade74814a/Image/b3d257b73b4b87a67be666bfdbe06eea/blogxbarrchart.jpg

In X-bar chart the sample means are plotted in order to control the mean value of a variable.

In R chart the sample ranges are plotted in order to control the variability of a variable.

In S chart the sample standard deviations are plotted in order to control the variability of a variable.

For controlling quality characteristics that represent attributes of the product, the following charts are commonly constructed:

C chart plots the number of defects; per batch, per day, per feet, etc. This chart assumes that defects of the quality attribute are rare, and the control limits in this chart are computed based on the Poisson distribution. http://www.centerspace.net/blog/wp-content/uploads/2010/07/c-chart-R.png

U chart shows the number of defectives divided by the number of units inspected. Unlike the C chart, this chart does not require a constant number of units, and it can be used, for example, when the batches are of different sizes.

Np chart; in this chart, we plot the number of defects (per batch, per day,) similar to the C chart. However, the control limits in this chart are not based on the distribution of rare events, but rather on the binomial distribution. Therefore, this chart should be used if the occurrence of defects are not rare, they occur in more than 5% of the units inspected. http://www.icsolutions-us.com/files/npChart_Healthcare.jpg

P chart, shows the percent of defects (per batch, per day, etc.) like the U chart. However, the control limits in this chart are not based on the distribution of rare events but rather on the binomial distribution. Therefore, this chart is most applicable to situations where the occurrence of defectives is not rare.

Total Quality management:

TQM is a philosophy that seeks to integrate all organizational functions to focus on meeting customer needs and organizational objectives.

The simple objective of TQM is to do the right things, right the first time, every time. TQM is infinitely variable and adaptable. Although originally applied to manufacturing operations for a number of years, TQM is now becoming recognized as a generic management tool, just as applicable in service and public sector organizations. TQM is the foundation for activities, which include:

Commitment by senior management and all employees

Meeting customer requirements

Reducing development cycle times

Just in time/demand flow manufacturing

Improvement teams

Reducing product and service costs

Systems to facilitate improvement

Line management ownership

Employee involvement and empowerment

Recognition and celebration

Challenging quantified goals and benchmarking

Focus on processes / improvement plans

Specific incorporation in strategic planning

Elements of TQM:

Customer focused: Total quality management realizes that the level and efficiency of quality is mainly determined by the customers. Regardless of what work is done to implement quality processes and decision it’s highly depended on the consumer. Customer is the one in the end determining whether the effort was worthy or not.

Total employee involvement: All employees participate in working toward common goals. Total employee commitment can only be obtained after fear has been driven from the workplace, when empowerment has occurred, and management has provided the proper environment. High-performance work systems integrate continuous improvement efforts with normal business operations. Self-managed work teams are one form of empowerment.

Process-centered: A fundamental part of TQM is a focus on process thinking. A process is a series of steps that take inputs from suppliers and transforms them into outputs that are delivered to customers. The steps required to carry out the process are defined, and performance measures are continuously monitored in order to detect unexpected variation.

Integrated system: Although an organization may consist of many different functional specialties often organized into vertically structured departments, it is the horizontal processes interconnecting these functions that are the focus of TQM.

Strategic and systematic approach: A critical part of the management of quality is the strategic and systematic approach to achieving an organization’s vision, mission, and goals. This process, called strategic planning or strategic management, includes the formulation of a strategic plan that integrates quality as a core component.

Continual improvement: A major thrust of TQM is continual process improvement. Continual improvement drives an organization to be both analytical and creative in finding ways to become more competitive and more effective at meeting stakeholder expectations.

Fact-based decision making: In order to know how well an organization is performing, data on performance measures are necessary. TQM requires that an organization continually collect and analyze data in order to improve decision making accuracy, achieve consensus, and allow prediction based on past history.

Communications: During times of organizational change, as well as part of day to day operation, effective communications plays a large part in maintaining morale and in motivating employees at all levels. Communications involve strategies, method, and timeliness.

Activates for Communication plan In TOTAL:

Activities

Required Predecessor

Analyze the situation

Reconfirm or set communication goals

Set efficiency targets

Decide on implementation strategy

Determine and specify the communication activities

Set budgets

Set evaluation methodology

Generate Communication activities

(none)

A

B

B

B

B, C, E

F

G

C

H

G

F

E

D

B

A