Comparing Manufacturing Processes: Continuous vs. Batch Manufacturing Malhotra Girish, President, EPCOT International, Pepper Pike, OH, USA Emulsion and solvent-based coatings have traditionally been produced one batch at a time and packaged in appropriate containers for sale to customers. This process has been very effective. Over the years, new raw materials have been developed to enhance paint performance and lower production costs, but the method of paint manufacturing has not significantly changed. With today's push toward lower prices and increased profits, many manufacturers are looking for ways to improve their production process. New methods such as semicontinuous and continuous manufacturing make it easier for manufacturers to increase quality and save money ---benefits that might well outweigh the cost of change. Limitations of batch Manufacturing While advances have been made in batch manufacturing processes, there are still many limitations that affect production. New process controls are now being used to control the addition of various raw materials and to minimize the batch cycle time, but adjustments still have to be made to ensure that each batch meets its specifications. These adjustments extend batch cycle time and can lead to operating problems when the scheduled batches cannot be completed. These operating problems affect the rest of the organization, including raw material inventory management, logistics, and sales and marketing. To reduce these problems, companies create larger than necessary buffers of raw material and finished goods inventory, but this increases the amount of working capital required. In batch production, small quantities of various raw materials are often measured manually. This can cause batch-to-batch variation, which is accommodated by having a broad product specification that still meets market needs. The size and power differences of the plant equipment can also influence the batch. This can result in two batches of the same product that both meet specification, but might be closer to the upper or lower end of the specification range. Since paint is produced in batches, the odds are that no two batches will be exactly same. As a result, the performance of the coatings can suffer, leading to customer dissatisfaction. Factors that can influence the cycle time and specification come from the raw materials used in batch production, including binder, pigments, and other additives, each with their own specification. If you combine all of the factors involved in paint manufacturing, it is easy to see that the industry has done a good job of producing coatings that satisfy the majority of the users' needs. A Move Toward Change Over the past 10 to 15 years, coatings have become a commodity with growth equal to or only slightly less than the gross domestic product. Home centers have become a way of life, and they sell at "everyday low prices". This puts tremendous pressure on paint manufacturers to reduce costs in an effort to increase profits. Increasing the profits of coatings manufacturers could require a shift in manufacturing. Other industries have changed their manufacturing processes and have improved their return on investment, but the coatings industry has lagged behind. Perhaps the time has come to implement such a change in this industry. Semicontinuous or continuous manufacturing has been demonstrated to work and create products with better quality control, more narrow specifications and lower cost. These processes can simplify manufacturing, and improve research and development, sales and marketing, supply chain management and IT implementation. Changing from a batch to a semicontinuous or continuous process can improve the efficiency of raw materials used and can reduce batch cycle time, resulting in consolidation of operations. The logistics of the operation can also improve, and the supply chain management will be easier to implement. Coatings produced by a semicontinuous or continuous process have higher consistent performance because the element of human error has been taken out of the equation. These processes also reduce capital investment and improve asset usage due to increased throughput. Changing to these processes could also result in raw material consolidation, which will further reduce cost and improve profitability. Another benefit is lower waste generation (pollution prevention), which will also reduce the capital investment needed to treat this waste. The concept of going from batch to continuous process is simple, but should be carefully considered because it impacts every functional group of any organization. Not every product can be produced continuously due to its total market requirement. Each company has to decide the best manufacturing process for its products. Conclusion Shifting from batch manufacturing to semicontinuous and/or continuous manufacturing can provide several benefits. These include improved profitability, product quality, supply chain management and logistics; lower investment (better asset use); lower raw material cost (improved efficiency); and lower labor cost. While specific benefits can vary from company to company, it is worthwhile to take a second looking at changing the manufacturing operation. Paint and Coatings Industry, 100-103, February 1999 Close