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SMED Techniques for Quick Changeovers
Center of Excellence SMED Techniques for Quick Changeovers School of Operational Excellence October 2006
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Objectives What is Changeover? What is Quick Changeover & How is it Beneficial? Six Stages of Changeover Improvement Tools Used for Changeover Improvement Summary & Bibliography
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SMED Quick Changeover Training Objectives
In order to promote improved changeover times and and reap the benefit of Availability improvement in our OEE, this session will: Define changeover Define Quick Changeover Discuss the goals of Quick Changeover Identify the benefits of Quick Changeover Illustrate the impact on key performance indicators Define stages of Quick Changeover Describe how to apply Quick Changeover approach
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Objectives What is Changeover? What is Quick Changeover & How is it Beneficial? Six Stages of Changeover Improvement Tools Used for Changeover Improvement Summary & Bibliography
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What is Changeover & What is Changeover Time?
The process of changing from one production run to another The total elapsed time required to change from the last good piece of a production run to the first good piece of the next run at full production rate or speed
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Objectives What is Changeover? What is Quick Changeover & How is it Beneficial? Six Stages of Changeover Improvement Tools Used for Changeover Improvement Summary & Bibliography
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What is Quick Changeover?
Quick Changeover is A performance improvement activity that focuses on: Reducing the changeover time Reducing the cost and effort required to perform a changeover Extracting the benefits that streamlined changeovers provide to many related areas of the production system
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Benefits of Quick Changeover
Why reduce changeover time? Increase production capacity Increase the number of changeovers Reduce batch sizes Decrease inventory levels Reduce lead time Increase flexibility to respond to customer demand Create competitive advantage
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Traditional Changeover Vs. “Pit Stop Mentality”
To understand the basic concept of Quick Changeover/SMED, it helps to look at cases outside manufacturing. A classic example is the pit stop process for a race car… it involves a host of practices that minimize the time and effort required Changing a tire on the side of the road A pit stop tire change VS. Car is not positioned in a good spot Driver must change tire on his or her own Driver is not well prepared or trained Tire jack is hard to locate and prepare Tire jack is manual and slow to raise the car Wheel nuts are hard to remove and require many turns for removal and installation Time and performance is not tracked, only concern is that job is complete Car is quickly positioned in ideal spot Driver has coordinated team for change Pit crew team is well trained and practices often High speed jack is ready to use before pit stop Tire jack is automatic and raises car almost instantly High speed air tools remove and attach nuts in under under a second Time and performance is tracked religiously, and crews are graded for their speed and accuracy
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Classic Quick Changeover: Airport Arrival/Departure
Commercial airlines face a significant penalty when valuable assets are “down” at the gate Goal: Fast turnaround of aircraft with minimum delay to departing and arriving passengers Unload/load baggage on roller conveyer with bar-coded baggage tracking Preposition full and empty baggage carts Preposition fuel truck for high-speed fuel dump Prebrief pilots Precook, package, and load meals Perform computer-assisted plane preflight check Use flexible ramp jet way Use marked taxi and park lines Precheck passengers and position close to gate Use 2nd service door to enable parallel food and passenger loading 9 6 8 7 4 5 767 737 10 1 3 2 8
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Quick Changeover: Milk Filler
Goal: Minimize filler machine downtime Load new product caps while last of old caps are being used in feeder tube Sequence product to minimize amount of purging required (e.g., run dark beverages at end of day) Have new product already flowing through feed lines while last of old product is being used in bottling chamber Have all machine programs preloaded Have quick change procedure for label feeder Operator from other line assures that bottles of old and new product are not mixed in crates (while main operator does core changeover activities) 1 2 3 4 5 6
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Traditional Views of Changeovers: Myths!
Long production runs and large batches are necessary to offset changeover costs Increased inventory costs are offset by reducing changeover costs when an economic order quantity is produced (EOQ) Changeover time is fixed and cannot be reduced But changeover can be reduced
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Quick Changeover Example
Current situation Improved performance Customer demand = 2,500 drums Reduced changeover time Product mix = A B C D E 40 minutes to 10 minutes Cycle time = 9.8 seconds per drum No. of changeovers = 4 per day Changeover time = 40 minutes Lead time = 1 day Time Available = 450 minutes No. of changeovers = 1/day A B C D E Batch size = 2,500 drums Day 1 Lead time = 5 days A B C D E Day 1 A CHANGEOVER Day 1 A B C D E Day 1 Day 2 B A B C D E Day 1 C Day 3 A B C D E Day 1 D Day 4 E Day 5 Do more changeovers!
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Quick Changeover Leads to Performance Benefits
Quick changeover can lead to either more frequent setups or an increase in available production time, both of which can substantially improve plant performance 1 hour changeover 6 times/day A B C A B C Total available daily run time = 18 hours 30 minute changeover 12 times/day Same run time, more changeovers Less inventory, more flexibility, shorter run times and lead times Inventory costs Customer service A B C D E A B C D E A B B C D Total available daily run time = 18 hours OR Can use to increase capacity 30 minute changeover 6 times/day Same changeovers, more run time OEE is . . . Less downtime, more available production time with same resources Downtime costs OEE A B C A B C Product mix could affect which strategy you would pick, depending on fiber, steel, or plastic Total available daily runtime = 21 hours
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Objectives What is Changeover? What is Quick Changeover & How is it Beneficial? Six Stages of Changeover Improvement Tools Used for Changeover Improvement Summary & Bibliography
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Six Stages of Changeover Improvement
A proven six-stage methodology can be used to apply Quick Changeover Stage Pull systems should precede or coincide with Quick Changeover implementation Observe and measure the total changeover time Separate internal and external steps Convert as many internal steps as possible to external steps Eliminate waste from internal steps Eliminate waste from external steps Standardize and maintain the new changeover procedure
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Stage 1: Observe & Measure Total Changeover Time
The first stage in a Quick Changeover program involves determining the baseline changeover time What is the correct method of measuring changeover time? Changeover time should be recorded as the interval between the stopping and full-speed restart of operations - normally between the last good part produced in a production run and the first good part produced in the next production run Actual shop floor measures and recording of changeover times often provides the only picture of the current conditions on the floor. 0 minutes CHANGEOVER TIME 60 minutes Last GOOD piece First GOOD piece
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Stage 2: Separate Internal & External Steps
The second stage involves determining what steps could be performed outside the actual changeover process Internal steps External steps Activities occurring during the changeover that can only be performed when production is shut down Activities that could be performed during a production run This is the critical driver for Quick Changeover improvements – a high percentage of operations are usually external steps that could be done before or after the changeover process Machine is operating Remove dies Change blades or tooling Loosening/tightening critical bolts Cleanup Tool preparation and retrieval Assemble subcomponents Paperwork
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Stage 2: Separate Internal & External Steps cont.
The first stage in a Quick Changeover program involves determining the baseline changeover time CHANGEOVER TIME First GOOD piece Last GOOD piece 0 minutes 60 minutes 20 minutes EXTERNAL INTERNAL EXTERNAL Identify when the activity occurs during the current environment Determine if internal activities can be converted to external
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Stage 3: Convert Internal to External
The first stage in a Quick Changeover program involves determining the baseline changeover time CHANGEOVER TIME First GOOD piece Last GOOD piece 0 minutes 60 minutes 20 minutes EXTERNAL INTERNAL EXTERNAL 15 minutes EXTERNAL INTERNAL EXTERNAL Any activity that does not have to be performed when the machine is not running should be converted to an external activity, such as clean up paperwork, tools in a safe manner
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Stage 3: Convert Internal to External cont.
The third stage involves moving steps outside the changeover process Examples of external steps that may be moved outside of the changeover process Current changeover step Improvement proposal Retrieve die from die storage area Heat die to operating temperature after installing in machine Gather tools, bolts, connectors, etc. Clean die from last run before removal Do paperwork for last run Contact changeover personnel when production finished and wait for them to arrive Stage die at press before changeover begins Preheat mold before changeover begins Pre-stage all materials necessary ahead of time Clean die in die shop between runs Wait until run begins to complete paperwork Perform changeovers to a planned schedule and contact personnel before production stops, or train operators to perform their own changeovers
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Stage 3: Convert Internal to External cont.
The third stage involves moving steps outside the changeover process Stage tools in the area before the changeover so time will not be spent retrieving them during the changeover process Stage dies at the machines prior to beginning the changeover Wait until the changeover is complete to fill out paperwork
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Stage 4: Eliminate Waste from Internal Steps
The fourth stage involves shortening the time required to perform steps during the changeover 0 minutes CHANGEOVER TIME 60 minutes Last GOOD piece First GOOD piece 15 minutes EXTERNAL INTERNAL EXTERNAL 10 minutes EXTERNAL INTERNAL EXTERNAL Last GOOD piece First GOOD piece Utilize quick release tools to reduce part exchange Implement positive stops to reduce positioning Design standard parts to eliminate part exchange Relocate parts and materials to reduce walking, searching, gathering time
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Stage 4: Eliminate Waste from Internal Steps cont.
The fourth stage involves shortening the time required to perform steps during the changeover Current method Improved method Fastening Positioning Adjustments Loosen attachment bolts Use manual tools (wrench, screwdriver, etc.) Use bolts and nuts Adjust to center manually Adjust front-to-back position manually Use different die heights in same press Manually adjust temperature and speed (using trial and error) Manually set programs for automated equipment Use fewer or shorter bolts Use air tools Use quick (1-turn) fasteners Use center pins and guides Use stop-blocks to ensure proper position Standardize die heights Set temperature and speed at pre-determined standard Pre-load programs
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Stage 4: Eliminate Waste from Internal Steps cont.
Use slotted washers and holes Use locator pins and guides Use standard die heights or standardized blocks
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Stage 4: Eliminate Waste from Internal Steps cont.
A Spaghetti Diagram can be used to analyze the walk patterns of changeover operators and improve the efficiency of the internal steps Spaghetti diagram Map out current walking path used in current state changeover Problem solve around wasted motion during changeover
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Stage 4: Eliminate Waste from Internal Steps cont.
A Spaghetti Diagram can be used to analyze the walk patterns of changeover operators and improve the efficiency of the internal steps Spaghetti diagram Note reduced Wasted motion Map out future state path to be used in changeover after eliminating waste
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Step 4: Eliminate Waste from Internal Steps
A Spaghetti Diagram can be used to analyze the walk patterns of changeover operators and improve the efficiency of the internal steps Changeover framework provides guidelines and possible solutions to eliminate waste Eliminate Make external Make fast Make parallel Stage • Checklists • Preposition all tools and material close and complete • Organize for sequential use • Use extra man • Automation Fasten • Eliminate excess fastening points • Redesign for natural-gravity fit with no fasteners • Remove/attach noncritical parts externally • Modular subassembly • Reduce threads • Specialized tools • Air wrench • Clamps • T/U slots • Magnetics • Hydraulics Load/align • Improve access to critical parts to avoid nonessential load/unload • Separate critical subparts for minimal action • Bolsters • Subassembly • Roller beds, air beds • Forklift/crane loading • Guide rails, pins • Hydraulic/air loading • Man-aids • Jigs/floor marks • Fail-safe alignment Test • Fix machine to eliminate source of variance • Raise fitting tolerances • Pretest or pre-fit on "mock" unit • Clamping • Quick measurement devices • Visual marks for fit Surface preparation • Protective cover • Pretreat • Preclean • Preheat • Specialized clean/prep tools, e.g., air/vacuum
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Stage 5: Eliminate Waste from External Steps
CHANGEOVER TIME First GOOD piece Last GOOD piece 0 min 60 min 10 minutes EXTERNAL EXTERNAL INTERNAL EXTERNAL 10 minutes EXTERNAL INTERNAL EXTERNAL Reduces total changeover time and improves OEE Reduce required paperwork to eliminate waste in external activities Relocate storage to reduce travel time and motion Utilize standardize checklist to improve efficiency and accuracy
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Step 5: Eliminate Waste from External Steps cont.
The fifth stage involves streamlining the steps performed external to the changeover Examples of external steps that can be improved Current situation Improvement Storing tools in a central storage area Searching for/retrieving materials that are required to perform a changeover Performing uncoordinated preparation activities before changeover begins Storing tools in local area near equipment where they will be used Ensuring that proper materials are provided in all areas of the plant Using a standardized preparation checklist Machine is operating with new die External work is organized and made more efficient
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Stage 6: Standardize & Maintain
Document the improved changeover procedure Communicate to all involved Training individuals responsible for changeover Post standard work instructions for changeover Establish a changeover goal Measure, post, and track all changeover times Time Last Best 6:30 minutes 5:00 Day 1 2 3 4 5
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Stage 6: Standardize & Maintain
The sixth step involves standardizing the improved process, including training and auditing personnel to assure adherence Changeover Standard Procedure Sheet No. Step Planned time Minutes Actual time Minutes Remarks 1 Shut down machine 2:00 1.75 2 Remove die 1:00 1.00 3 Input computer settings 2:25 3.00 Difficulty inputting 1 setting 4 Insert new die 1:00 1.00 5 Unload old material 0:50 1:00 Slight feeder jam 6 Load new material 1:25 1.00 7 Restart machine 1:25 1.00 8 Start production 0:75 0.50 Totals 10:00 10:25 Total changeover time has been reduced, and machine downtime has been reduced from 60 minutes to 10 minutes, thus enabling batch size reductions, inventory reductions, and freeing 50 more minutes of machine run time. With 3 changeovers per shift and 2 shifts per day, this opens an additional 300 minutes of productive machine time daily, which enables an organization to increase production and/or avoid capital investments that may have been required without the Quick Changeover. Additionally, OEE is improved
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Objectives What is Changeover? What is Quick Changeover & How is it Beneficial? Six Stages of Changeover Improvement Tools Used for Changeover Improvement Summary & Bibliography
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Post-It Notes Method Example
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Post-It Notes Method Example
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Tools for Analyzing Changeovers: Post-It Notes
USING “POST IT NOTES” METHOD Video the changeover prior to Post It Note exercise Using a video of changeover, identify all steps, from start to finish, number in order with time in seconds. Place info on Post it Notes Identify step as INTERNAL or EXTERNAL (use “I” or “E”) on Post it Notes Put Post it Notes on Wall in numbered order Identify steps that can be eliminated and place Post It Notes in row marked “eliminate” Separate INTERNAL from EXTERNAL (Make row(s) of internal and row(s) of external) Convert INTERNAL to EXTERNAL where possible (identify improvement idea* and move Post it Note to External row)
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Tools for Analyzing Changeovers: Post-It Notes
USING “POST IT NOTES” METHOD Identify steps that can be done in parallel and place Post It Note in row marked “parallel” Eliminate Waste from INTERNAL steps (make faster) (identify improvement idea*, change time on Post it Note) Eliminate Waste from EXTERNAL steps (make faster) Establish “NEW” Changeover time from Post it Notes, prepare Standard Operations Instructions for changeover * Keep track of improvements by step number
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SMED Time Savings Spreadsheet: Example 1
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SMED Time Savings Spreadsheet: Example 2
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Tools for Analyzing Changeovers: Spreadsheet Example 2
FOLLOW THE LEARNED STEPS WHILE USING A SPREADSHEET List all the steps in order, numbered, with time in seconds Record time for steps eliminated in “Eliminate” column If an internal step is made faster record time saved in “Make Faster” column If an internal step is converted to external record time in “External” column If step is converted to one done in parallel record time in “Parallel” column Spreadsheet automatically displays New changeover time total and percentage savings Create Standard Operation Instructions NOTE: Place descriptive notes on changes made in right-hand column
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Use Targets to Maintain Improvements Over Time
The standardization step should include tracking the performance of the Quick Changeover program, assuring the new process generates the proper performance output Target Average June changeover times for Line 23 Targets must address . . . Changeover time Man-hours/ changeover Minutes 70 Analysis 60 50 . . . to ensure that the anticipated benefits are being realized First trial 40 Second trial Target 30 20 10 Pull systems create a sense of urgency that forces changeover reductions to be maintained and improved 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Day
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Objectives What is Changeover? What is Quick Changeover & How is it Beneficial? Six Stages of Changeover Improvement Tools Used for Changeover Improvement Summary & Bibliography
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SUMMARY Changeover time is the total clock time from last good piece to first good piece at full production speed Quick Changeover is a performance improvement tool to reduce changeover time and cost Reduced changeover time can create a competitive advantage by lowering inventory cost, reducing batch sizes and lead time and increasing responsiveness to customer demand There are 6 Stages of Quick Changeover: Observe and measure the total changeover time Separate internal and external steps Convert internal to external Reduce the internal steps Improve the external steps Standardize and maintain the new changeover procedure Measure and post changeover results Establish targets DO MORE CHANGEOVERS!
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REFERENCE MATERIALS Quick Changeover for Operators: The SMED System created by The Productivity Press Development Team A Revolution in Manufacturing: The SMED Systems by Shigeo Shingo 20 Keys to Workplace Improvement by Iwoa Kobayashi Toyota Production System: An Integrated Approach to Just-in-Time by Yasuhiro Monden
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Detail For SMED Game as modified K Svendsen,DJW
SET UP OF GAMES Fours person teams Timekeeper Quality person Assembler Recorder of steps Take amount of fixtures apart that you will need back to bolt posts leave in Set up all parts away from work centers Washers and pins mixed all together in piles or cups This equals one tool crib Die parts as well blue and red Wrenches and scales all in one area Team for Job 1 is to build to spec in the shortest amount of time Record main steps Record time for main steps QC to help hit spec Capture total time
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Detail For SMED Game as modified K Svendsen,DJW
JOB 1 completed with red die inserted should be 8 to 10 minutes DISCUSS: What could we do to improve What took the longest to and caused most problems in time JOB 2 GIVE Shadow boards and allow to stage dies and spare parts( Washers) at machine Change to Blue die should be approx 2 to 3 Minutes DISCUSS: What took the longest discuss issues ( usually the location of the die left and right and the thickness issue again ) JOB 3 GIVE Die Block Spacer discs plus Screw and Allen wrench combo Put Blue back in and change to Red Usually 1 to 1 ½ Minutes
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Detail For SMED Game as modified K Svendsen,DJW
DISCUSS: What could we do to improve What took the longest to and caused most problems in time Usually centering die or location of die JOB 4 Give the die pins then change back to blue Approx 6 Seconds Discuss Can we cut even more Have clamp system pre- built and show that with slide in and hit clamp may achieve 50% more reduction 10 minutes to 3 seconds ??
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