Low-volume/high-complexity industries are known for their unique designs and custom products, which require extremely flexible manufacturing processes. Implementing Lean principles is the best way to enhance flexibility and achieve success by offering the "best price in the market" and "fast delivery." However, the application of Lean principles depends on the type of production layout and business. Continuous production processes and variable production processes have distinct demands and targets. Applying the same Lean terminology to both industries can result in losses in terms of inventory, safety stock, pull systems, and takt times. This paper aims to address the common problems faced by low-volume/high-complexity industries and demonstrate how Lean techniques and thinking can resolve them. This paper aims to explain the cost benefits resulting from process improvement in the Volume-1 case study. It further explores process improvements in different complex areas, providing a clearer explanation of how lean thinking transforms complex processes into flexible ones. The focus on improving the paint and shipping processes stems directly from customer feedback regarding quality non-conformances and new customer development. Additionally, special process audits by new customers have influenced this focus. To illustrate the practical benefits of Lean thinking in industrial development and highlight the differences between low-volume/high-complexity industries, we will examine the industrial painting process. Industrial painting involves a range of complex tasks, including storing, mixing, spraying, testing, data availability, tools arrangement, inventory management, climate control, paint estimation, spray procedures, measuring devices, lighting quality, and layout optimization for smooth product flow. Jones Metal Inc. serves as an excellent example of a high-volume/complex industry. Improving process quality and maintaining acceptable performance levels are crucial for the success of any organization. Lean thinking provides an opportunity to enhance process flexibility for successful organizations. This paper first explains the current processes of the complex industry and then demonstrates how lean thinking contributes to the development of these processes.