Statistical Quality Control. Bhisham C. Gupta
of experiments (DOE). DOE is used to improve the process and find important control factors, whereas SPC monitors these factors so that the process remains in a steady state. SPC is one of the important tools that makes up SQC. However, the term statistical process control is often used interchangeably with statistical quality control.
1.2.1 Quality and the Customer
The customer or consumer plays a very important role in achieving quality, for it is the customer who defines the quality of the product. If the customer likes the product and is satisfied with it the way it functions, then the probability is high that they will be willing to buy the product again in the future, indicating that you have a quality product. However, quality can also be achieved through innovation. Quality is not static; rather, it is an ongoing process. For example, a given product may be of great quality today – but if no further innovative improvements are made, it may become obsolete in the future and consequently lose its market share. It should be obvious that the required innovation can only be defined by the producer.
The customer is not in a position to tell how a product should look like 5 or 10 years from now. For example, five decades ago, a customer could not imagine electric cars or self‐driven cars, or small computers replacing the huge computers that used to occupy entire rooms. The customer is only the judge of the product in its current form. In other words, a concern about quality begins with the customer, but the producer must carry it into the future. The producer or their team has to incorporate their innovative ideas at the design stage. This is called continuous improvement or quality forever. We will have a brief look at this concept later in this chapter.
It is important to note that a customer can be internal or external. For example, a paper mill could be an internal or external customer of a pulp mill. If both the paper and the pulp mill are owned by the same organization, then the paper mill is an internal customer; otherwise, it is an external customer. Similarly, various departments are internal customers of the Human Resources department. Another example is that students from various departments of a university taking a course from another department are internal customers, whereas a part‐time student from outside the university is an external customer. In such cases, the company or organization should not assume that if its internal customers are satisfied, external customers are also automatically satisfied. The needs of external customers may be entirely different from those of internal customers, and the company must strive to meet both sets of needs. Furthermore, the goal of a company or an organization should be that all customers are satisfied not only for the moment but forever.
In summary, to achieve quality and competitiveness, you must first achieve quality today and then continue to improve the product for the future by introducing innovative ideas. To do this, an organization must take the following steps:
1 Make the customer its top priority. In other words, it should be a customer‐focused organization.
2 Make sure the customer is fully satisfied and, as a result, becomes a loyal customer. A loyal customer is the one who will always give reliable feedback.
3 Create an environment that provides the most innovative products and has as its focus quality improvement as an ongoing process.
4 Take data‐driven action to achieve quality and innovation. That is, the organization must collect information systematically, following appropriate sampling techniques to obtain data from internal as well as external customers about their needs and analyzing it to make necessary improvements. This process should be repeated continuously.
1.2.2 Quality Improvement
Different authors have taken different steps to achieve quality improvement. In this chapter, we quote the steps suggested by four prominent advocates of quality who revolutionized the field of SQC: Philip B. Crosby, W. Edwards Deming, Joseph M. Juran, and Armand V. Feigenbaum. We first discuss ideas suggested by Crosby, Feigenbaum, and Juran; later, we will look those from W. Edwards Deming.
Following are Juran's 10 steps to achieve quality improvement (Uselac 1993, p. 37; Goetsch and Davis 2006):
1 Build awareness of both the need for improvement and opportunities. Identify gaps.
2 Set goals for improvement.
3 Organize to meet the goals that have been set. They should align with the company's goal.
4 Provide training.
5 Implement projects aimed at solving problems.
6 Report progress.
7 Give recognition.
8 Communicate results.
9 Keep scores. Sustain these and continue to perfection.
10 Maintain momentum by building improvement into the company's regular system.
Next, we summarize Armand V. Feigenbaum's philosophy for total management (Tripathi 2016; Watson 2005):
Quality of products and services is directly influenced by nine Ms: Markets, Money, Management, Men, Motivation, Material, Machines and Mechanization, Modern information methods, and Mounting product requirements.
Three steps to quality: (i) management should take the lead in enforcing quality efforts and should be based on sound planning; (ii) traditional quality programs should be replaced by the latest quality technology to satisfy future customers; (iii) motivation and continuous training of the entire workforce gives insights about organizational commitment to the continuous quality improvement of products and services.
Elements of total quality to enable a total customer focus are as follows:Quality is the customer's perception.Quality and the cost are the same, not different.Quality is an individual and team commitment.Quality and innovation are interrelated and mutually beneficial.Managing quality is managing the business.Quality is a principle.Quality is not a temporary or quick fix.Productivity is gained by cost‐effective, demonstrably beneficial quality investment.Implement quality by encompassing suppliers and customers in the system.
Feigenbaum was the first to define a system engineering approach to quality. He believed that total quality control combines management methods and economic theory with organizational principles, resulting in commercial leadership. He also taught that widespread quality improvement performance in a nation's leading businesses is directly related to quality's long‐term economic impact.
Philip B. Crosby is well known for his “Quality Vaccine” and 14 steps to quality improvement. The Quality Vaccine consists of the following three ingredients:
Determination
Education
Implementation
Crosby's suggested set of 14 steps to quality improvement are as follows (Goetsch and Davis 2006):
1 Make it clear that management is committed to quality for the long term.
2 Form cross‐departmental quality teams.
3 Identify where current and potential problems exist.
4 Assess the cost of quality and explain how it is used as a management tool.
5 Increase the quality awareness and personal commitment of all employees.
6 Take immediate action to correct problems that have been identified.
7 Establish a zero‐defects program.
8 Train supervisor to carry out their responsibilities in the quality program.
9 Periodically hold “zero defects days” to ensure that all employees are made aware there is a new direction.
10 Encourage individuals and teams to establish both personal and team improvement goals.
11 Encourage employees to tell management about obstacles they face in trying to meet quality goals.
12 Recognize employees who