JIT Basics (SMED, TPM, Standards) | My Assignment Tutor

EG7322 Lean EngineeringSession 8: JIT Basics (SMED, TPM, Standards)Marina MarinelliMEng MSc PhD FHEAm.marinelli@leicester.ac.ukStrut toarm28 secStrut/arm tobase18 secStrut/arm/baseto cap14 secAddbottomclip14 secInspectbot 8 sec 4 secSide tobaseSide/b/l 26 secto cap10 secAdd topclip10 secSide/base toleg24 sec4 secInspecttop 8 secAt SLMS, the assembly operation consists of 12distinct operations done by 4 operators in each shift.60 sec50403020100 Strut toarm28 secSide tobase26 sec Side/b/lto cap10 secStrut/arm tobase18 secStrut/arm/baseto cap14 secAddbottomclip14 sec4 sec4 secInspecttop 8 secInspectbot 8 secOperator Balance Chart- Current StateSide/  maintain the flow of the operatiobase toleg24 secAdd topclip10 sec Operator 146 secOperator 250 secOperator 338 secOperator 434 secDetermine the number of operators needed by dividing total product cycle time by takttime. Operators needed = 168 / 60 = 2.8Takt timeLine balancingmove the elements around on the chart 60 sec50403020100 Strut toarm28 secStrut/arm/baseto cap14 sec4 secInspectbot 8 secThe ideal situation is to have eveoperator working at takt timeSide/b/lto cap10 secStrut/arm tobase18 secAddbottomclip14 sec4 secInspecttop 8 secSide/base toleg24 secSide tobase26 secAdd topclip10 sec Operator 160 secOperator 260 secOperator 348 secLine balancing Pieces/day = 230,400 (annualvolume) /240 days = 960 piecesMachine Capacity BalanceMachine Capacity BalancePieces/day = 230,400 (annualvolume) /240 days = 960 piecesMachine Capacity BalancePieces/day = 230,400 (annualvolume) /240 days = 960 piecesFor Tool #S98-010 Run seconds/day = 960 pieces/day x 23 second cycle time= 22,080 sec = 368 minFor Tool #S98-008 … 960×34 = 32640 sec = 544 minFor Tool #S98-014 … 960×23 = 22,080sec = 368 minChangeover time for mold: 2 hrs = 120 minx3 timesChangeover time for colour: 15 min x6 times S98‐008Run time544 minS98‐010 runtime 368 min120 min T/C120 min T/CS98‐014 runtime 368 min120 min T/CTop baseTop capBottom capContinuous overtime requirPress no1 90 min CL/T144012001000800600400200Available time3*8*60=1,440 min1440*0.9=1,296Machine Capacity Balance ChartCurrent State • A process for changing over production equipment from one part number toanother in as little time as possible. SMED refers to the target of reducingchangeover times to a single digit, or less than 10 minutes.• A die is a piece of hard metal used to shape sheet metal.• Stamping machines create desired shapes out of sheet metal “blankets” by bringingmatched lower and upper dies together under thousands of pounds of pressure.https://www.youtube.com/watch?v=r9byGJtbCwsSingle Minute Exchange of Die (SMED)Machine Capacityhttps://www.youtube.com/watch?v=pUhVQhcCyawhttps://www.youtube.com/watch?v=ieLdyW-OiYIhttps://www.youtube.com/watch?v=81OlkDCLdwETotal Productive MaintenanceTPM: A set of techniques to ensure that every machine in a productionprocess always is able to perform its required tasks.It seeks total productivity of equipment by focusing on all of the six majorlosses that plague equipment: downtime changeover time minor stops speed losses1. Downtime  Equipment breakdowns2. Change over time  Setup and adjustment delays (e.g., because of die changes instamping presses or injection molding machines) 3. Minor stops Idling and minor stoppages (the machine is being run but noproduct is processed) Reduced speed (the actual machine speed is less than thedesign speed)4. Speed losses5. Scrap6. Rework Process defects that require repair  scrap reworkTotal Productive MaintenanceTPM: A set of techniques to ensure that every machine in a productionprocess always is able to perform its required tasks.It seeks total productivity of equipment by focusing on all of the six majorlosses that plague equipment: downtime changeover time minor stops speed losses scrap reworkOverall Equipment Effectiveness (OEE)Availability rate Performance rate Quality rateIf Availability is 90%, Performance is 95% and Quality is 99%OEE=0.90 x 0.95 x 0.99 = 84.6%Availability Rate x Performance Rate x Quality Rate = OEEThe approach is termed total becauseFirst, it requires the total participation of all employees, not onlymaintenance personnel but line managers, manufacturing engineers, qualityexperts, and operators.Second, it seeks total productivity of equipment by focusing on all of the sixmajor losses that plague equipment: downtime, changeover time, minorstops, speed losses, scrap, and rework.Total Productive MaintenancePreventive maintenance: equipment servicing approachconsidered a precursor to TPM that is based on regularly scheduledchecking and overhauling by maintenance personnel to decreasebreakdowns and increase equipment life.Unlike traditional preventive maintenance, which relieson maintenance personnel, TPM involves operators inroutine maintenance, improvement projects, and simplerepairs. For example, operators perform daily activitiessuch as lubricating, cleaning, tightening, and inspectingequipment.11030100sBreakdown(function loss)Minor stoppage(function reduction)Minor failures(no function reduction)Hidden failures(no function reduction)LooseNuts and boltsVibration causesbearing deteriorationMotor OverheatingMotor burns outListen and watch for minor anomaliesand take action before breakdownTotal Productive MaintenanceStandardsWhy are they important in the lean system?Standards make abnormalities immediatelyobvious so that corrective actions can be taken.What makes an effective standard?A good standard is simple clear visualStandard: A clear image of a desired conditionThe bedrock of production is standards: what is supposed to happen.The bedrock of excellence is adherence to standardsVisual ManagementLean is about making problems visible.You can’t fix what you can’t see.Four levels of visual management in order of increasing powerLEVEL 1—TELLS ONLYLEVEL 2—SOMETHING CHANGES, WHICH GETSYOUR ATTENTIONLEVEL 3—ORGANIZES BEHAVIORLEVEL 4—THE DEFECT IS IMPOSSIBLEStep 1: Develop a deep grasp of our process and possible failure modes.Step 2: Install devices and/or practices that make them impossible.The placement in plain view of all tools, parts, production activities, and indicatorsof production system performance, so the status of the system can beunderstood at a glance by everyone involved.Α standard can beA one‐page standardised work chartA painted silhouette on a wall showing what jigs and tools belong thereA delivery schedule board on a receiving dock showing what deliveries areexpected and which ones have arrived on timeA visual display showing the department’s capacity, throughput and cycle timetargets, current project load, and what phase each project is in, and what themain problems are.Key point: It’s easy to see what should be happening.Consider a quality standard for paint finish.Here are three types of standards and their relative power:Written description in the supervisor’s desk drawer: low powerPicture posted in the workplace: higher powerActual sample of both good and bad conditions posted at the point of use:highest powerVisual Management• Draw a happy pigDRAW A HAPPY PIG!• 0 PICK UP YOUR PEN (1sec)• 1 Draw a letter M at the top left intersection. Bottom center of M touches the intersection (3 sec)• 2 Draw the letter W at the bottom left intersection. Top center of W touches the intersection (3 sec)• 3 Draw the letter W at the bottom right intersection. Top center of W touches the intersection (3 sec)• 4 Draw an arc from the letter M to the top right intersection (2 sec)• 5 Draw another arc from the top right intersection to the bottom right W (4 sec)• 6 Draw an arc between the two bottom Ws (2 sec)• 7 Draw a circle in the center left box (3 sec)• 8 Draw an arc from the letter M to the tangent of the circle ( 2 sec)• 9 Draw an arc from the left W to the tangent of the circle ( 2 sec)• 10 Draw an arc for the eye. Half way between M and circle (2 sec)• 11 Draw an arc for the mouth. Half way between W and circle. Must be a happy pig! (2 sec)• 12 Draw the letter e near the top of arc on the right (3 sec)• 13 Draw two dots in the middle of the circle for the pigs nose (3 sec)• 14 Put your pen down (1 sec)Standardised workStandard: A clear image of a desired conditionStandardised work1 Draw a letter M at the top left intersection. Bottomcenter of M touches the intersection2 Draw the letter W at the bottom left intersection.Top center of W touches the intersectionDraw an arc from the letter M to the top right intersection• The process tells the team member what to do, when to do it, and in what order.• Standardised work is:Standardised work• The most effective combination of workers, materials, and machines forthe sake of making high‐quality products cheaply, quickly, and safely.• Safest, easiest and most effective way of doing the job that we currentlyknow.• A process is simply a set of steps or actions with a clearly defined goal.• A tool for developing, confirming, and improving our processesStandardised work1. There is a single best way (and the engineers will find it).2. Workers are not involved in designing the work or making improvements.3. Standards rarely change (and only the experts can change them) There is no one best way to do the work. Workers should design the work. The purpose of standardised work is to provide a basis for improvement.Requires establishing precise procedures, highly specified as to the content,the sequence, the timing and the outcome for each operator’s work in aproduction process.Standardised work, comprises:Work contentTimingSequence Expected outcomeEmbedded tests that signal OK/Not OKTime measurement entails breaking a process into its elements andmeasuring the instant each element starts and stops.Steps:Standardised work1. Become familiar with the process area and its surroundings.2. Identify the work elements and their sequence.3. Measure total cycle time (at least 10 times).4. Measure the time for each work element (at least 10 times).5. Identify and measure irregular work (e.g., clearing blockages).A work element is the minimum action or group of actions required toadvance a process.For example, picking up a bolt is an action but does not advance theprocess. Picking up a bolt and installing it on a work piece is a group ofactions, which advances the process.Work contentWork element sheetWork element sheets are one‐pagers that defineActions making up the job elementRationalePictures and photos highlighting key points to perform the job safely with utmostquality and efficiencyRevision recordUsed to train newoperatorsStandardised Work Combination TableShows the combination of manual work time, walk time, and machine processing timefor each operator in a production sequence.Standardised work chartShows operator movementand material location inrelation to the machineand overall process layout.Standardized work charts often are displayed at workstations as a tool for visualmanagement and kaizen.They are continuously reviewed and updated as the condition of the worksite changesor improves.Thank you