Design of Experiments (DOE): Applications and Benefits in Quality Control and Assurance

*Sheriff Lamidi, Rafiu Olalere, Adekunle Yekinni and Khairat Adesina*

## **Abstract**

This chapter explores the applications and benefits of Design of Experiments (DOE) in the context of quality control and quality assurance. DOE is a statistical methodology that enables researchers and practitioners to systematically investigate and optimize processes, identify critical factors affecting quality, and reduce variability and waste. This chapter begins by introducing the overview and definitions of DOE, covering topics such as the history of DOE, types of DOE, steps involved in conducting DOE, and key components of DOE. The specific applications of DOE in quality control and quality assurance were explored, highlighting their importance across various industries. It demonstrates how DOE can be effectively applied to optimize products and processes, reduce defects and variation, improve quality, implement Six Sigma, and validate and verify processes. It then delves into the specific applications of DOE in quality control and assurance, highlighting its significance in various industries and sectors. Furthermore, the book addresses challenges and considerations in implementing DOE in real-world scenarios, such as resource constraints, experimental constraints, and data analysis complexities. It provides basic information on software tools commonly used in DOE.

**Keywords:** design of experiments (DOE), quality, quality control, process variability, optimization

#### **1. Introduction**

Quality control and assurance are crucial aspects of any manufacturing or industrial process. Ensuring high-quality products and services is essential for customer satisfaction, brand reputation, and overall business success. Quality is a measure of the level of conformance of a product to design specifications or the ability of a product or service to satisfy user requirements. The duo of quality assurance and quality control helps deliver a defect-free product or service. Quality assurance focuses on preventing defects by ensuring the approaches, techniques, methods, and processes designed for the projects are implemented correctly. Quality control, on the other hand, focuses on identifying defects by ensuring that the approaches,

techniques, methods, and processes designed in the project are followed correctly [1]. Quality assurance is process-oriented and a managerial tool, whereas quality control is product-oriented and a remedial tool, according to [1]. One powerful tool used in quality control and assurance is the design of experiments (DOE). According to engineers and technologists, they often make use of DOE methodologies for various applications ranging from the design of new products, improvement of design, maintenance, control and improvement of manufacturing processes, maintenance and repair of products, and several others [2–4]. This chapter aims to explore the applications and benefits of DOE in quality control and assurance. Design of experiments (DOE) is a statistical method for planning and conducting experiments. DOE is used to identify the factors that affect a process and to determine the optimal levels of those factors, as shown in **Figure 1**. DOE can be used to improve the quality of products and processes, reduce costs, and increase efficiency [5]. Businesses and manufacturing companies can use Design of Experiments (DOE) in a variety of ways to differentiate themselves from the competition by constantly redesigning their products or creating new products to establish a presence in other markets. First, DOE can be used to identify the factors that most affect the quality of a product. By understanding which factors are most important, businesses can focus their efforts on improving those factors. This can lead to a product that is more reliable, durable, and user-friendly than the competition's products. Second, DOE can be used to reduce the cost of manufacturing a product. By identifying the most efficient way to produce a product by optimizing manufacturing processes using DOE methodologies, businesses can improve the quality of their products and save money on labor, materials, and other costs [6]. This can lead to a lower price for the product, which can make it more competitive. Third, DOE can be used to develop new products that meet the needs of a specific market. By understanding the needs of the target market, businesses can develop products that are more likely to be successful. This can help businesses gain a foothold in new markets and increase their market share.
