Describe how Lean principles can be integrated into the Improve phase to optimize processes, providing examples of specific Lean tools and techniques.
Lean principles, focused on eliminating waste and maximizing value, are highly complementary to the Six Sigma methodology and are particularly powerful when integrated into the Improve phase of a Six Sigma project. While Six Sigma aims to reduce variation and defects, Lean focuses on streamlining processes, removing non-value-added activities, and improving flow. By combining these two approaches, the Improve phase can achieve a more efficient, faster, and higher-quality process.
One of the fundamental ways Lean principles are integrated is through the identification and elimination of the eight types of waste, often referred to as "DOWNTIME," an acronym for Defects, Overproduction, Waiting, Non-utilized talent, Transportation, Inventory, Motion, and Extra-processing. During the Improve phase, Lean tools are used to identify these types of waste and then create strategies to eliminate them or minimize their impact.
For example, if the project analysis has identified "waiting" as a significant issue, a Lean tool like Value Stream Mapping (VSM) can be used to visualize the current state of the process and identify areas where bottlenecks or unnecessary wait times occur. The VSM visualizes the flow of materials and information and shows where delays occur. For example, in a restaurant setting, a VSM can show the entire process from the customer's order to the customer receiving their meal. It can reveal that long wait times between food preparation and food delivery are a major source of delays. The Lean solution, would be to implement a "First-In-First-Out" (FIFO) system in the kitchen. Here, food is prepared in the order that it is received, instead of chefs completing each menu item in batch, which may cause dishes to wait before being delivered. The FIFO will reduce the wait time and deliver food quicker while it's fresh.
Another example relates to "motion" waste. In a hospital, moving between different equipment and patient areas can take a lot of time and energy. To mitigate motion waste, a Lean approach can be applied to redesign the workspace using the 5S methodology (Sort, Set in Order, Shine, Standardize, and Sustain). By implementing 5S principles, a medical equipment supply area may be rearranged to ensure that all frequently needed items are readily available within the working area. For example, frequently used items such as IV fluids can be placed closer to nursing stations, reducing the unnecessary motion required for nurses to find what they need. In effect, the team is improving the efficiency of how their working area is set up.
"Transportation" is another type of waste that can be reduced. For example, if a warehouse has a non-optimized layout, products may need to be moved multiple times before they are shipped out. This can result in excess effort and increase the risk of damage. Implementing a cellular layout design, which groups related processes together in a smaller physical space, will reduce the distance that items must travel and streamline product flow.
Lean also emphasizes reducing "inventory" waste. Too much inventory on hand ties up capital, increases storage costs, and leads to greater risks of obsolescence or spoilage. Lean tools like Just-in-Time (JIT) inventory management can be applied to ensure that materials are received only when they are needed in the production process. For example, if a bakery is producing daily bread, JIT can be used to ensure only flour is purchased just in time for the day's production, reducing the amount of flour sitting in the warehouse.
The application of Lean also ties into "Overproduction." This is when products are made in excess, leading to unnecessary storage costs, inventory control issues, and potential waste if items don’t sell. Using a Pull system, which is where production begins only after receiving an order, can help mitigate this waste. For example, if a furniture store is producing made to order custom pieces, it should avoid manufacturing products that have not been requested, which helps to reduce the excess inventory and production.
In addressing "Defects," another type of waste, Lean tools like Poka-Yoke (mistake-proofing) can be used to prevent defects from occurring in the first place. This is done by implementing design solutions into the process to avoid mistakes. In a car manufacturing plant, a Poka-Yoke may be to implement specific tools that ensure all screws are torqued correctly, so as to avoid under-tightening or overtightening which leads to defects.
Another form of waste is related to "Non-Utilized Talent", where employees’ skills are not being used to their fullest potential. Lean can encourage a cross-training program, where employees can engage in activities across the entire organization, so there is a higher level of engagement and their talents are utilized to a higher degree.
Integrating Lean into the Improve phase also emphasizes quick improvements and iterative cycles using the Plan-Do-Check-Act (PDCA) approach, where solutions are implemented, their effects are measured, adjustments are made, and they are adopted into standard procedure. This creates continuous improvement and also encourages process stability.
By using Lean principles and techniques during the Improve phase, Six Sigma projects can move beyond simply reducing variation and defects to create a more efficient process, better flow, less waste, and more value for both the business and its customers. It’s about building a process that is not only high quality but also fast, cost-effective, and easy to manage.