39. Rapid Changeover (SMED) Overview Rapid changeover or rapid setup is also known as Single Minute Exchange of Dies (SMED) and was devised by Shigeo Shingo[69] during the period 1950 and 1969. SMED was developed primarily with three Japanese companies, Mazda, Matsuzo, and Toyota and since then has revolutionized the entire Automotive and Metal Fabrication industries. It is obviously at home in all discrete-manufacturing industries, but is equally applicable to most service industries, for instance, in healthcare for room cleaning and turnover and more obviously in hotels where the room turnover occurs between the noon checkout and the 3 p.m. check-in time. [69] For more information, see A Revolution in Manufacturing: The SMED System by Shigeo Shingo published by Productivity Press.
By reducing changeover times, businesses gain significant benefits from reduced costs per unit, lot sizes, Process Lead Time, inventory costs, and setup errors. Businesses also gain increased capacity (and therefore reduction in the need for excess capital equipment), yield, quality, and safety. More consistent, effective changeovers and setups also simplify scheduling by creating a more predictable process. Changeover time is the actual clock time, not labor time or work content, so it is possible to start a stopwatch at the commencement of the changeover and stop it at the completion. The key to reducing the changeover time is to have a more encompassing definition of the time itself as shown in Figure 7.39.1. Traditionally, changeover is often considered just to be the tool change time when in fact the lost time is much greater and is better defined as Figure 7.39.1. An example machine changeover in discrete manufacturing industry. 
The amount of time between the end of the last VA step of the previous run to the beginning of the first value-added step of the next run. An example changeover is shown for a hospital treatment room in Figure 7.39.2. Traditionally the changeover was considered just to be the room cleaning, whereas the actual lost time is much greater. Figure 7.39.2. An example of changeover for a hospital Treatment or Operating Room. 
The reasons for long changeovers stem primarily from inconsistency and lack of ownership. Individual operators often do changeovers as they see fit, based on their own experiences and no two operators changeover the same way. Often operators on one shift are not comfortable with a changeover or setup done on a previous shift. Therefore, changeovers are repeated and some operators even think that quality is better with a longer changeover. Logistics Although changeover reduction should be used on an ongoing basis, the first work in an area is typically done as an "Event." The event duration is anywhere from one day for a small piece of equipment to perhaps a 45 day event in a larger more complex process. Typical event duration is three days. The key elements to have in place prior to an event are Support. A SMED event is not a small affair and significant change is likely made. This requires solid leadership support to ensure success. The event should have a clear Owner/Champion that kicks off the event and serve as the Customer for the event. Scope. When conducting an event, the biggest failure is usually due to scope creep, so set a clear, focused, bounded process area to tackle during the event period and don't be tempted to move beyond this area. People. Having the right people involved is crucial. SMED is an active Team sport and requires people that actually do the work in the target area. Key functions to involve are Operators and Supervisors The most important members of the Team are those who actually operate the equipment and perform changeover tasks. Process Engineering Act more in a support role, adding technical expertise and implementing and building on operators' ideas. Maintenance Are often involved in the changeover itself and are also good resources for mechanical ideas and fixture design. Quality Assurance Quality checks often add significant time to changeovers and so QA involvement can help reduce this time.
Communication. All parties involved in and affected by the event need to know of its existence and implications to them. The other functions listed in the previous "People" bullet also need to be informed that work needs to be done "there and then" rather than be put on a To-Do List for future change. SMED follows the Kaizen mentality of doing it today, instead of planning it to be done over a period of weeks; hence the need for strong Leadership support. The rule in all Process Improvement is always to communicate ten times more than you would expect. Equipment, Supplies, and Ancillary Items. Most of the event is done in the process area itself, but another quiet area is required to train the Team briefly on the SMED process and to serve as a work area at times through the event. Facilitation equipment and supplies are necessary, such as flipcharts, pens, and perhaps, an LCD projector and screen to show the training materials and to work on the Critical Path Analysis. Videoing the changeover before and throughout the event is crucial to analyze the activity. Ideally one video camera per changeover operator is required. Work is likely done on laying out the area. An enlarged blueprint or CAD drawing of the process plan is needed.
Roadmap After the Team is formed and trained in SMED methods, the roadmap is as follows: Step 1. | Baseline current performance. It is important to establish an accurate baseline for changeover downtime with enough detail to make a distinction between setups, changeovers, and other downtime. This data should be reported at least monthly in the form of hours or as a percentage of available machine time.
If this data is not available historically, then it can be calculated approximately from Step 2 along with the number of changeovers made in a period.
| | | Step 2. | Video a current changeover. A video camera is the best tool for gathering changeover data; without it the all-important details are missed. The whole changeover needs to be recorded in one sitting, so a separate camera is needed to record each operator in the changeover in parallel.
Make sure that the cameras have on-screen timers, or if not then put a large digital clock in a strategic location in the area to track the time.
Be sure to inform the operators about the video recording ahead of time, in fact it is preferable to use the operators in the Team to be the guinea pigs for the recording if possible to alleviate some Hawthorne effect. Perhaps even video multiple changeovers and use the last one where the Hawthorne Effect is minimized. Be sure to capture the entire changeover from the end of the last VA step to the beginning of the next. If any pre- or post-changeover work is done, then expand the scope of the recording accordingly.
Focus on the details of the changeover activities as much as possible and don't be tempted only to set up a tripod and come back when the changeover is complete, too much detail is lost.
| Step 3. | Analyze the video recordings and document the changeover with the operators involved to complete the first four columns of an SMED Time Analysis Chart for the changeover, as shown in Figure 7.39.3.
Figure 7.39.3. SMED Time Analysis Chart. 
| | | Step 4. | Classify the changeover steps as they are currently into internal and external time:
- Internal Operations. Those operations that are performed only when the machine is not running. Examples include changing a fixture on a machine or changing a bed ready for the next patient. Place the step time for internal operations in Column 5 in the SMED Time Analysis Chart.
- External Operations. Those operations that might be performed while the machine is running. Examples include organizing tools, preparing new fixtures, getting material, and so on. External operations can be performed either before or after the changeover. Place the step time for external operations in Column 6 in the SMED Time Analysis Chart.
Identifying the tasks that are currently being performed as internal operations, but could potentially be completed externally, is a key to reducing changeover time.
| | | Step 5. | Generate ideas to reduce the changeover time using the SMED Time Analysis Chart. There is no prescriptive approach here, but the primary places to focus include the following:
Moving internal items to external by doing the following: Dividing the changeover activities by resource and apply Critical Path Analysis to each resource. On the Critical Path strive to do the following: Eliminating all NVA activities Eliminating or reducing other activities Moving activities off the Critical Path
Improving organization by the following. Note that 75% of the reduction can come from organization and 5S. The area is sorted and cleaned All necessary tools are nearby with the use of shadow boards for hand tools Paperwork and checklists are posted in the area Visual flow of work through area with incoming and outgoing lots clearly are identified near the area Dedicated tool or die carts are used for each machine People, tools, and parts are organized in the work area before a changeover: After a changeover begins, the participants should never have to leave the area Everyone and everything involved with the setup is waiting for the "machine" to shut down All operators follow a routine
Reducing or removing elements in the changeover by doing the following: Using one-touch equipment exchange (no adjustments, only touch the equipment once) Using clamps or quick-release devices to attach tools, fixtures, air and water leads, and so on
Eliminating adjustments and trial runs. Adjustments and test runs can account for as much as 50% of changeover time. Strive to eliminate them completely, not just reduce the time taken to perform adjustment. Breaking the practice of running equipment, testing it, adjusting, running more trial product, and so on. No product should be spoiled during setup. Replacing infinite adjustments with mechanical stops. Designing fixtures, tools, and associated equipment so that they are self-positioning. Using digital readouts instead of dials and manual measuring tools when adjustment is absolutely necessary.
Standardizing the area with the following: Determining which entities are going to run on the machine, then evaluate the equipment to see if it can be modified to serve each without changeover. Determining what tools, tool holders, and supplies are currently being used, then evaluate each to see if one can replace several. Size standardization often allows the use of common fixtures, dies, and tools. Standardizing all fasteners (size and type) on all fixtures. Determining if gauges used can be standardized or simplified.
Simplifying the area by the following. Using fewer parts during setup by combining functional pieces. Making it obvious when the setup is complete and correct (stops, gauges, and so on). Creating pre-kits of all non-standard tools and storing in staging area. Ensuring tool kits are clearly marked with part numbers. Ensuring information on supplies sheets are updated. Making someone accountable for preparing changeover kits prior to changeover. Simplifying mounting and removal of dies, fixtures & chucks. Arranging all tools and supplies at point of use, by frequency of use. Operators should not have to move or turn frequently for tools.
Mistake proofing Color coding or marking all standardized tools, fixtures, jigs for identification and where they are used. Using pins, blocks, or stops for quick alignment if parts, dies, or fixtures can be oriented in more than one way. Using preset stops, limit switches, light switches, proximity switches and standardized settings Using Total Productive Maintenance principles to ensure that all tools, dies, materials, and supplies are defect free and working properly.
Problem solving. Things not happening or working the way they were designed can cause as much as half the time spent on a changeover. The goal is not to look for ways to make the setup easier in spite of these problems, but to eliminate them altogether. Anything that stands in the way of a perfect, trouble-free setup is viewed as a problem: Missing or bent fixtures Unsharpened, worn, or misplaced tools Out-of-specification supplies Mechanical failures
| Step 6. | Create the Improvement Plan. Document the Team's ideas and form two project lists:
Short-term action items that can be completed immediately with little or no capital requirements. All action items should have clear owners and due dates. Long-term projects that are more involved and might require capital and equipment modifications. Project owners should be allocated.
| | | Step 7. | Execute the Improvement Plan to install the new changeover process.
| Step 8. | Control:
Write new changeover procedures and best practices. Provide training across all shifts to standardize the new setup procedures. Document and publish the results of the new changeover process. Continue tracking changeover time to monitor results Strive for continuous improvement Recognize and reward outstanding improvements
| Step 9. | Proliferate to other machines or work-centers, so that best practices are being implemented across all machines.
None of the steps in the roadmap involve alchemy or rocket science. Most improvements involve just common sense, organization, and changes in basic attitudes.
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