Changeover improvement is vital for modern factories due to changing market demands and the need to minimize waste and inventory while reducing costs. By optimizing changeovers, factories can respond swiftly to customer requirements, streamline processes, and enhance efficiency and quality. This ensures competitiveness in a dynamic manufacturing landscape where diverse product models and short delivery deadlines are prevalent.
Types of Changeover Operations
- Exchanging Dies and Blades : Common in machining shops, involves swapping metal dies, molds, drill bits, or saw blades. Suitable for JIT improvement to enhance efficiency.
- Changing Standard Parameters : Required for computer-programmed cutters and chemical processing equipment. Operators adjust standard parameters for different processing tasks, necessitating highly trained personnel for smooth operations.
- Exchanging Assembly Parts or Materials : Occurs when an assembly line switches to assembling a different product model, involving exchanging parts or materials. Includes die changing and may involve switchover or retooling of equipment components.
- General Set-up Prior to Manufacturing : Encompasses various tasks such as equipment arrangement, job assignment, drawing verification, and cleanliness checks before manufacturing commences.
Approach to Changeover Times
- Reframing Changeover Time: Shift focus from the start-to-finish duration of operator activities to a definition that emphasizes from the end of one processing task to the production of a defect-free product in the next task.
- Internal Changeover Time: Recognise this as the duration when the machine doesn’t contribute value to the workpiece. It starts after completing the current task and ends when the next task produces a defect-free product.
- External Changeover Time: Acknowledge the time operators spend on setup procedures while the machine operates. This is independent of machine activities.
- Total Changeover Time: Understand it as the sum of internal and external changeover times, as per the equation: Changeover time = Internal changeover time + External changeover time.
- Comprehensive Improvement: Address both internal and external changeover procedures to achieve holistic changeover improvement.
Procedure for Changeover Improvement
- Form a Changeover Kaizen Team:
- Recognize the need for changeover improvement and establish a dedicated team.
- Ensure strong support from upper management for the team’s initiatives.
- Analyze Changeover Operations:
- Identify and analyze changeover processes taking excessive time.
- Utilize JIT changeover improvement tools like changeover result tables and analysis charts for insight.
- Eliminate Wasteful Operations:
- Categorize changeover operations into internal, external, and wasteful categories.
- Apply the 5S’s (Sort, Set in order, Shine, Standardize, Sustain) to eliminate waste.
- Transform Internal Changeover to External:
- Innovate ways to convert internal tasks requiring machine downtime into external tasks feasible during machine operation.
- This transformation significantly reduces overall changeover time.
- Improve Remaining Internal Changeover:
- Review remaining internal changeover procedures after transforming some into external tasks.
- Explore methods to reduce time, such as minimizing bolts, developing cassette units, or parallelizing procedures.
- Enhance External Changeover:
- Implement time-saving improvements in both internal and external changeover processes.
- Focus on establishing proper arrangement, specialized machines, and providing additional training in changeover-related skills.
By following these steps, factories can systematically improve changeover operations, reducing downtime, increasing efficiency, and enhancing overall productivity.