Rework Quantification and Influence of Rework on Duration and Cost of Equipment Development Task

• Main Authors: Xilin Zhang, Yuejin Tan, Zhiwei Yang
• Format: Article
• Language: English
• Published: MDPI AG 2018-10-01
• Series: Sustainability
• Subjects: equipment development task; foreseeable rework; hidden rework; uncertainty; complexity
• Online Access: http://www.mdpi.com/2071-1050/10/10/3590

Rework is a sub-task within equipment development tasks that is revised after initial completion to meet task requirements. Some sub-tasks require multiple rework iterations due to their uncertainty and complexity, or the technology and process needs of the overall task, resulting in inefficient task implementation and resource wastage. Therefore, studying the impact of rework iterations on the duration and cost of development tasks is worthwhile. This study divides rework into foreseeable and hidden types and uses several methods to express and quantify their parameters. The main influencing factors in rework iterations—the uncertainty and complexity of the development task—are quantitatively analyzed. Then, mathematical and mapping models of the dependence between sub-tasks, uncertainty, complexity, and rework parameters are established. The impacts of rework type and rework parameters on the duration and cost of equipment development tasks are analyzed via simulation based on the design structure matrix (DSM). Finally, an example is used to illustrate the influence of different rework types and rework parameters on development tasks’ duration and cost. The results show that the duration and cost of development tasks are greater, their volatility range is wider, and the distribution is more dispersed when both foreseeable and hidden rework are considered.