Capability studies, helpful tools in process quality improvement

Abstract

Abstract. Ability of processes to meet customer'quality requirements has become essential for providing competitive advantages such as cost savings, reducing the number of nonconfoming products or increasing customer satisfaction. This paper aims to conduct a capability study for a swaging process (that ensures an assembly dimension) of a key product characteristic (the outer diameter of a new part), related to the concept of capability and performance indices and how these metrics can be used and interpreted to become powerful tools for decision making. To achieve the goal of the paper, the following key aspects were analyzed: capability of the measurement system capability (gage R&R), production equipment (machine) capability and process capability/performance during the first serial production. The analysis was performed with Minitab® 17, the most commonly used software for quality improvement. Process variationAs a matter of fact, in any process, regardless of how well designed or carefully maintained it is, a certain amount of inherent or natural variability will always exist [1]. This type of variation is the cumulative effect of many small causes, named common, chance or random causes. These types of causes produce a consistent and predictable type of variation over time. A process that is operating with only common causes of variation present is said to be a stable process or in a state of statistical control. Sometimes, dominant sources of variation may appear, that are not part of the process and they are named as special or assignable causes. These types of causes are not predictable and are sporadic in nature.It is important to know what type of variation is present in a process, because the action one takes for the process improvement depends on the type of variation. If special causes of variation are present, they should be first identified and then eliminated; the next step is to reduce common cause of variation.Competitive companies understand that satisfying the needs of customers and running a successful operation requires processes that are predictable and consistent. The variation which is present in a process (whether it is a business or a manufacturing process) is the main cause of the quality problems, so measuring variability and finding ways to reduce it, is essential for the success of any company.

Capability Studies as a Key Driver for Product and Pro-Cess Quality Assurance in Industrialization Process

“…The third issue to consider is the chosen methods and measurement equipment and their ability (R&R) to reach prescribed targets, accompanied and influenced by the human factor. During capability evaluation in the pre-serial stage, a short-term capability approach is used, while in the initial flow stage and serial production within CSE management, the long-term capability is employed (Simion, 2017;Dian, 2017Dian, , 2018. Based on the known and previously described methodology, the first step of the Capability study process is the determination of the most important characteristics of the product, the CSE (Tab.…”