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As many organizations begin their journeys toward a lean enterprise, they are finding the road to be difficult and filled with obstacles. The question that is most asked is where to begin.
While the market is increasingly demanding more customized products, manufacturers are under constant pressure to reduce costs. Non-fulfillment of orders more frequently results in losing business to the competition. Combine these factors with the high cost of inventory and the need to increase productivity, and it becomes obvious that mastering quick changeover is essential to an organization’s survival.
As an organization begins a lean manufacturing implementation, its ultimate goal is to produce according to customer demand (takt time) while utilizing ”one piece flow.” For this to happen, machines need to be set up more often, highlighting the need to reduce setup time. Reducing setup time results in increased production, better quality parts and a more flexible workplace.
Single-minute exchange of dies (SMED), similarly known as quick changeover, like other lean tools, requires a committed effort from within the organization. One of the major pitfalls organizations fall into is the desire to rush into a changeover program with very little or no upfront planning. With limited time and resources, the program is doomed for failure. The other common mistake is failure to document and standardize the process. Finally and most importantly, management must demonstrate a full commitment to the program. If the changeover program is not a high priority to management, then it will not be a priority to anyone else.
Preparing for Analysis
As an organization prepares for the program, it must first ask the question: Why are we doing this? The obvious reason is always to reduce costs, but cost reduction and improved profitability will come as a result of inventory reduction, smaller batch sizes, increased plant capacity, quicker response time to customers, and better use of employees. Goals for each of these need to be set and reported to the entire organization. This early preparation will greatly benefit a changeover implementation. Also a critical step, the organization must determine which area or process will be attacked first. Value stream mapping is an effective technique for identifying bottlenecks and prioritizing areas of improvement.
The next step is to form an implementation team. The composition of the team is very important to its success. Determining factors should include knowledge, interest, ability to work with others, and, of course, enthusiasm. The team will have regular members that attend every meeting and are directly involved with the changeover: setup technicians, line mechanics, operators, supervisors, and manufacturing and quality engineers. The other members will consist of representatives from other departments within the organization. They will not have to attend every meeting but will have a role to play, especially when their areas are being addressed. Some examples (but not a comprehensive list) of other areas to be represented include finance, human resources, manufacturing, materials, purchasing and planning.
After the team is formed, each member needs to be trained in the principles of SMED/quick changeover, basic problem solving, root cause analysis and (often overlooked) proper procedures for conducting meetings. A well-developed training program that includes interactive exercises is beneficial for the team as it begins to meet regularly and to analyze the changeover process.
When the daily meetings begin, ground rules need to be set. Every meeting will have a leader and an agenda; tasks will be assigned and minutes taken. Structured, well-run meetings will reduce the implementation time and will increase participation and the quality of ideas.
The first step in the analysis is to videotape every detail of the entire changeover process from cleanup to setup. The only exceptions are normal breaks such as lunch. It is important that the changeover being filmed is a normal changeover. If anything abnormal occurs, the changeover needs to be refilmed. (Note: A simple setup of a camcorder on a tripod is sufficient. You won’t need to bring Steven Spielberg in on this one.)
The next step is to create a baseline of the process. Each detail of the changeover process must be identified and listed. The video should be reviewed several times until the team is sure that they have identified and listed everything that takes place.
After every detail is documented, the team members will conduct a brainstorming session in which each element on the list will be analyzed and classified into one of four categories.
Eliminate: Is the step really necessary?
Externalize: Remember, the key is not so much reducing the total amount of labor as reducing the length of time the line is down. One way to reduce downtime is to externalize tasks to the maximum extent possible.
“Externalization” means performing changeover tasks either before or after the changeover, “externally” to the changeover time. One common activity that takes place during changeover is that the operator will collect the various change parts required. If this is done during the changeover, it will extend changeover time. This is something that can be done ahead of time so that all the required parts are available the moment they are needed.
Simplify: Any elements that cannot be eliminated or externalized need to be simplified where possible. This will include the elimination of tools, use of slots and keyholes, quick connectors, and the like. As part of simplification, all adjustments must be made measurable. This may be done with digital position indicators, scales or scribe marks. Gauges also may be used, but these are “tools” and should be avoided wherever possible.
No Change: Finally, there will be many elements for which no improvements are possible. This is OK, but they need to be identified as such. Periodically, they should be re-examined in case process changes, new ideas or new technologies allow improvement.
Once each step has been classified, they then need to be prioritized. A good method to follow is to classify each one as an A, B or C. “A” items can be done immediately. “B” items require a bit more time to implement for varying reasons. “C” items are the long-range items such as new equipment.
This is the point at which some organizations end the process. When organizations go this far and do not implement any of the ideas, they are in essence adding a ninth waste to the eight wastes of manufacturing. Instead of walking away with nothing more than improvements on paper, the team should now develop an action plan with each task assigned to team members with a due date. Status of every item should be reported at each meeting.
The new process should then be documented and each operator trained. The new procedure will become standard for that setup. The SMED/changeover program should also have a standard operating procedure (SOP) generated for the next event. As the organization improves each setup after this, new members should be brought in and trained until everyone in the organization has been trained in changeover process improvement. Eventually, the organization will be become a true lean enterprise where everyone routinely contributes to process improvements.
Though the high cost of downtime always justifies changeover reduction, the process can be a very painful and daunting one. Many times, companies have tried and failed to develop a successful SMED/quick changeover program. Using the ideas and steps outlined in this article will certainly improve the likelihood of success.
About the author:
David McBride is co-founder of EMS Consulting Group (http://www.emsstrategies.com), a Carlsbad, Calif.-based engineering and management consulting firm. David has a bachelors of science degree in mechanical engineering from Ohio State University. He has a successful track record in the development and implementation of Failure Modes and Effects Analysis and Design for Manufacturability programs at several organizations and has greatly reduced manufacturing costs through the utilization of lean manufacturing, kaizen events and manufacturing system analysis. He has also been highly successful at developing and executing new product introduction processes, and staffing and capital equipment plans. To contact David about this article, send an e-mail to firstname.lastname@example.org.