The SMED changeover time is the time between the end of the previous run last value added step to the beginning of the first value-added step of the next run.
-Operators and supervisors.
Baseline current performance. Establish an accurate baseline for changeover downtime with enough detail to make a distinction between setups, changeovers, and other downtime. 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.
To prevent missing important details use a video camera to gather changeover data. Record the changeover in one sitting, so use a separate camera to record each operator in parallel. Focus on the details of the changeover activities as much as possible. Don't be tempted to set up a tripod, leave and then come back on the completed changeover. You may lose details.
Make sure the cameras have on-screen timers. If not, then put a large digital clock in a strategic location to track the time. Be sure to inform the operators about the video recording ahead of time.
Analyze the video recordings. Document the changeover with the operators. Complete the first four columns of an SMED Time Analysis Chart for the changeover, as shown below
Classify the current changeover steps into internal and external time
Internal Operations are performed only when the machine is not running. Examples include changing a fixture on a machine or changing a bed for the next patient. Place the step time for internal operations in Column 5 in the SMED Time Analysis Chart.
External Operations might be performed while the machine is running. Examples include organizing tools, preparing new fixtures, getting material, and so on. Place the step time for external operations in Column 6 in the SMED Time Analysis Chart.
Identifying the tasks currently being performed as internal operations, but could potentially be completed externally, is a key to reducing changeover time.
Generate ideas to reduce the changeover time using the SMED Time Analysis Chart. There is no prescriptive approach here, see the below for possible change over reduction solutions.
Create the Improvement Plan. Document the team's ideas and form two project lists. Create a short-term action list that can be completed immediately with little or no capital requirements. All action items should have clear owners and due dates. Create a long-term projects list that are more involved and might require capital and equipment modifications. Project owners should be allocated.
Execute the improvement plan to install the new changeover process.
Control the new changeover process. 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 the results.
Proliferate this event to other machines or work-centers. Implement these best practices across all machines. Focus on bottleneck areas first.
Ideas for Reducing Changeover Time
Move internal items to external by doing the following:
-Using pre-setup activities
-Tools cleaned and sharpened
-Gages preset and supplies ready
-Materials transported and sequenced
-Tools, fixtures, and supplies positioned
-Paperwork organized and prepared
-Using post-setup activities
-Clean, inspect, return, and repair tools, materials, and fixtures
-Store all items in assigned locations
Divide the changeover activities by resource and apply Critical Path Analysis to each resource. On the Critical Path strive to do the following:
-Eliminating all non-value 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
-Place all necessary tools nearby. Use shadow boards for hand tools
-Post paperwork and checklists in the area
-Visually identify all stages of production through the work through area. Clearly identify incoming and outgoing lots near the area
-Use dedicated tool or die carts for each machine
Organize people in the work area before a changeover:
-After a changeover begins, the participants should never leave the area
-Everyone and everything involved with the setup is waiting for the machine to shut down
-All operators follow a routine
-Make someone accountable for preparing changeover kits prior to the changeover.
Reduce or remove 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
Eliminate adjustments and trial runs. Adjustments and first articles can account for as much as 50% of changeover time. Strive to eliminate them completely, not just reduce the time taken to perform the adjustment.
-Break the practice of running equipment, testing it, adjusting, running more trial product, and so on. Spoil product during setup.
-Replace infinite adjustments with mechanical stops. Design 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:
-Determine which entities run on the machine, then evaluate the equipment to see if it can be modified to serve each without changeover.
-Determine the tools, tool holders, and supplies being used. Then evaluate each to see if one can replace several.
-Standardize size often. This 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.
-Make it obvious when the setup is complete and correct (stops, gauges, and so on).
-Create pre-kits of all non-standard tools and store in staging area.
-Ensure tool kits are clearly marked with part numbers.
-Ensure information on supplies sheets are up to date.
-Simplify mounting and removal of dies, fixtures & chucks.
-Arrange all tools and supplies at point of use, by frequency of use. Operators should not have to move or turn frequently for tools.
Implement mistake proofing
-Use color coding and marking on all standardized tools, fixtures, jigs for identification.
-Use pins, blocks, or stops for quick alignment.
-Use preset stops, limit switches, light switches, and proximity switches
-Use 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 causes time wasting issues during a changeover. Eliminate these issues altogether. View anything that stands in the way of a perfect, trouble-free setup as a problem
-Missing or bent fixtures
-Unsharpened, worn, or misplaced tools