Dependable production OEE, TPM, and RCM

Transcription

1 Dependable production OEE, TPM, and RCM Antti Salonen

2 How a production shift may look! Productive time Unproductive time Planned production time Start-up problem Set-up Break-downs Planned stopps Cleaning Period with small-stops Period with reduced speed Production 2

3 Overall Equipment Effectiveness Purpose: Show the disturbances that reduces the productivity of the equipment Show how effective the equipment is used by measuring loss factors Show that improving actions are adequate. Aid in planning of resources and workload 3

4 The six big losses Failures and break-downs Set-up and adjustments Idling and minor stoppages Reduced speed Defects and rework Start-up losses 4

5 What is OEE? X X Availability Performance rate Quality rate The OEE-value indicates the total effectiveness in production 5

6 OEE calculations Scheduled working time Planned production time Available operative time Net operative time Value adding operative time Defects Speed loss Unplanned stopps Planning related stopps Failures and breakdowns Set-up and adjustments Idling and minor stoppage Reduced speed Defects and rework Start-up losses Planning factor = Scheduled time Planning related stop time Scheduled time Availability = Planned prod. time Unplanned stop time Planned prod. time Performance rate = Bought CT x items produced Available operative time Quality rate = Items produced - Defects Items produced Overall Equipment Effectiveness (OEE) = (Planning factor) x = Availability x Performance rate x Quality rate 6

7 OEE calculations Planning factor = Scheduled working time planning related stop time Scheduled working time = 480 min - 80 min 480 min = 0,83 Availability = Planned production time unplanned stop time = 400 min - 90 min Planned production time 400 min = 0,775 Performance rate = Bought cycle time x items produced 0,6 Available operative time = min/piece x 412 pieces 310 min = 0,797 Quality rate = Items produced defect items Items produced = 412 pieces - 16 pieces 412 st = 0,96 OEE = 0,775 x 0,797 x 0,96 x 100 (%) = 59,3% PfOEE = 0,83 x 0,775 x 0,797 x 0,96 x 100 (%) = 49,2% 7

8 Three levels of measurement How to measure? Depending on purpose and aim with the measuring, the following three levels may be used: Level 1 Total utilization = Pftot x A x P x Q This level indicates how a plant is utilized compared to maximum available time (24hrs/day, 365 days/year) Level 2 Asset effectiveness = Pf x A x P x Q This level indicates how effective an asset is used regarding planned working hours Level 3 Equipment effectiveness = A x P x Q This level indicates how effective a specific equipment is used. 8

9 OEE: Total planning factor Calculation of Pf tot Theoretical available time (24h/day, 365 days/year) planning related stop time Theoretical available time (24h/day, 365 days/year) Planning related stop time is time loss that doesn t affect the equipment effectiveness. For example hollidays, breaks, meeting time, education, cleaning, waiting time due to surrounding equipment, PM, planned modifications, lack of orders, personell or material. Note. The use of 24h/day, 365 days/year for definition of Theoretical available time is common within process industries where heavy investments occur. 9

10 OEE: Planning factor Calculation of Pf Theoretical production time (scheduled) planning related stop time Theoretical production time (scheduled) Theoretical production time is the scheduled production time when the facility is manned. E.g. 3-shift (ca 110 hours/week), daytime (40 hours/week) Planning related stop time is time loss that doesn t affect the equipment effectiveness. For example hollidays, breaks, meeting time, education, cleaning, waiting time due to surrounding equipment, PM, planned modifications, lack of orders, personell or material. 10

11 OEE calculations Planning factor = Scheduled workingtime planning related stop time Scheduled working time Availability = Planned production time unplanned stop time Planned production time Performance rate = Bought cycle time x items produced Available operative time Quality rate = Items produced defect items Items produced OEE = A x P x Q x 100 = % PfOEE = Pf x A x P x Q x 100 = % 11

12 OEE calculation Calculate the OEE and PfOEE for a production unit under the following conditions: Work hours: 2-shifts, monday friday Shif hours: Morning shift 06:00 14:12 Afternoon shift 13:48 22:00, on fridays, the shift ends at 20:00 Breaks: 30 minutes lunch every shift, with no production Meetings: Department meeting every Thursday at 12:48 13:48 with no production Preventive maintenance: Every day at 13:48 14:00 Production rate: The bought cycle time is 6 minutes per piece. Events during the studied week: Break downs: monday, 08:30 10:00 wednesday, 07:00 10:12 thursday, 15:30 17:24 Planning factor = Scheduled time Planning related stop time Scheduled time Availability = Planned prod. time Unplanned stop time Planned prod. time Performance rate = Bought CT x items produced Available operative time Quality rate = Items produced - Defects Items produced Produced pieces: 523 of which 3 scrapped beccause of defects. 12

13 OEE: Calculation Scheduled working time 4x16h + 14h = 78h Planning related stops 2x5x0,5h + 1h + 5x0,2h = 7h Planning factor (Pf) (78-7h) / 78 = 0,910 Pf = 91,0% Planned production time 78h-7h = 71h Unplanned stop time 1,5h + 3,2h + 1,9h = 6,6h Availability (A) (71 6,6) / 71 = 0,907 A = 90,7% Available operative time 71h 6,6h = 64,4h Bought cycle time 6 min / 60 = 0,1h Produced items 523 st Performance rate (P) (0,1x523) / 64,4 = 0,812 P = 81,2% Scrap 3 st. Quality rate (Q) (523 3) / 523 0,994 Q = 99,4% PfOEE 0,910x0,907x0,812x0,994 0,666 PfOEE = 66,6% OEE 0,907x0,812x0,994 0,732 OEE = 73,2% 13

14 Defining Cycle time The following has to be explored: Manual loading time included? Other limiting factors affecting the cycle time? Can several products be produced during one cycle? Do different products have different cycle times? 14

15 Defining bought cycle time Cycle time according to equipment specification Cycle time according to product specification Lowest CT in similar equipment Lowest CT tested in the equipment Theoretically calculated CT Lowest measured CT Actual CT recalculated with ambition 15

16 Performance rate, P - when producing products with different CT s Product Theoretical CT, CT T (min/piece) Produced amount, P (piece) CT T x P (min) Sum CT T x P (min) Available operative time*, T.O.T (min) P = (Sum CT T x P) /T.O.T (%) * Planned production time Unplanned stops P1 P2 P3 P4 0,6 0,7 0,8 0, % 16

17 Increased OEE leads to. Less disturbances which in turn may lead to Improved planning ability Reduced risk of quality problems More time for developing work Released capacity which in turn may lead to Alternative to capacity investments Increased flexibility Decreased operative time Decreased number of equipments 17

18 Time for a break? 18

19 OEE in Swedish industry (2002) % OEE Interval 50 Average 60% Improvement potential 88% 40 80% Practically achievable Manufacturing industry 10 Electronics Mining Steel P & P Power Chemical OEE % 19

20 Utilization Results from a study of 30 Swedish sub suppliers in automotive industry (Nutek, 2008) Average OEE = 60,4% For comparison, a number of similar companies in other countries were studied: Average OEE in other countries = 77% 20

21 Utilization More findings from the study of 30 Swedish sub-suppliers in automotive industry (Nutek, 2008) Average OEE = 60,4% 39% of the companies measure and analyze time-loss and cause of failures 14% of the companies measure and analyze time-loss and cause of disturbances 86% of the companies perform systematic preventive maintenance 25% of the companies perform CBM 21

22 My own observations Poor utilization of the possibilities of analyzing data from CMMS Most companies fail to regard dependability aspects when investing Few companies use systematic RCA (Root Cause Analysis) Few companies use systematic maintenance concepts Few companies measure the cost of lost production 22

23 Concepts for increasing the dependability of production equipment TPM; Total Productive Maintenance RCM; Reliability Centered Maintenance 23

24 TPM what s that? Total Productive Maintenance Total Process Management Total Production Management And so on. 24

25 TPM - definition TPM can be defined as a systematic work method aiming to develop disturbance free processes at lowest possible cost through the commitment of all co-workers (LCP-Consultants) 25

26 TPM as a philosophy focuses on daily maintenance in manufacturing industries is built on total employee involvement born in the Japanese automobile industry. 26

27 TPM Total Productive Maintenance Total Effectiveness Total Preventive Maintenance Total Commitment 27

28 Why TPM? Replace routine with development Increased commitment from all co-workers Continuous improvements Foreseeable operations Improved safety and environment 28

29 TPM Structure Evaluation and new goals Preparation Implementation Management s decision Education Organisation and pilot Policy and goals Develop a master plan Kick-off Effectiveness Continuous improvements Autonomous maintenance Planned maintenance Education and training Early equipment management Quality maintenance Effective administration Safety, hygiene and environment 29

30 Group activities Autonomous maintenance group Cross functional improvement group Target oriented cross functional group 30

31 Improvement tools 7QC/QM Identify, prioritize and analyze failures FMEA Identify and evaluate potential weaknesses FTA Identify causes of failures and their logic connections PM-analysis Reduce all chronic loss to zero 31

32 Autonomous maintenance 32

33 Autonomous maintenance Teach the operators to react on cause instead of result By increased kompetence and understanding the operators may: Eliminate minor stoppages Prevent break-downs Secure implemented improvements Improve quality, safety, and environment In the long run operators start to perform maintenance tasks Daliy inspections replaces repair and low frequent controls Implemented through seven well-defined steps Takes long time to implement, often years 33

34 The seven-step ladder Description Competence Equipment focusing step. Secures the basic condition of the equipment Focuses the operators. They learn advanced inspection and maintenance techniques Factory focusing step. From maintenance to control. 3. Standards for cleaning and lubrication 2. Counter meassures at the problem source 1. Basic cleaning and order 6. Organize the work environment 5. Autonomous inspection 4. General inspection training 7. Autonomous maintenance Can find defects and understand the principles for improvements of the equipment Understands the functions and structure of the machines Repair skills Understands the relation between maintenance and product quality 34

35 Planned maintenance Activities for improved OEE Activities for improved maintenance effectiveness Corrective Maintenance Preventive Maintenance Restoring Maintenance Improvement Maintenance Condition Based Maintenance Maintenance planning Maintenance control Spare part control Economy control Information feedback Implementation of planned maintenance leads to: - Increased MTBF and MTBM - Decreased MTTR, MWT and M - Closer to 0-faults, 0-stops and 0-accidents 35

36 Early equipment management The process has to goals: To reach stable, full speed production at start-up. To, as far as possible, meet the detailed requirements for the equipment. Goal and requirements Project Basic properties Acquisition process LCC Structure and process thinking Experience development MP-design Early detection of problems The included activities are aiming for new equipment to be: Reliable and producing non defective products. Easy to mend and set up, and fast to start after set-up changes. Easy to maintain, and fast to localize faults and repair. Easy to clean, lubricate and inspect. Resource efficient and safe. 36

37 Quality maintenance 37

38 Results of TPM at Volvo Productivity Breakdowns reduced with 90% OEE increased from 50% to 90% MTBF increased from 30 minutes to 8 hours Quality Scrap reduced with 90% Cost of quality control reduced with 67% Customer complaints reduced with 75% Costs Production cost reduced with 30% Delivery precision Capital bound in WIP and finished goods decreased with 50% Fulfillment actual/desired delivery time increased to 90% Delivery precision actual/promised time increased to 100% Safety Accidents resulting in personal injuries reduced to 0 Accidents resulting in pollution reduced to 0 Commitment Ten times as many suggested improvements Time for education and training increased with 100% 38

39 RCM what s that? RCM has been defined as Reliability Centered Maintenance: a process used to determine what must be done to ensure that any physical asset continues to do what its users want it to do in its present operating context. (Moubray, 1997, p.7) 39

40 RCM Reliability Centered Maintenance, RCM Focuses on construction and development of products and manufacturing systems maintainability and to develop an effective and resource parsimoniuos PM before the product or system is up and running, born in the aircraft industry 40

41 RCM RCM is sprung from MSG (Maintenance Steering Group) that has been developed since the 1960s, for the purpose of the aircraft industry. RCM have since also been developed to be used in e.g. the power industry, energy industry, and in some cases also the manufacturing industry. 41

42 RCM With RCM methodology one handle the maintenance objectives as early as in the development phase on a consciously, rationally, and planned base. One analyses potential failure that can occur on the developed systems, structures, or components. Faults can be classified as obvious or hidden, safety critical or of considerable financial character. 42

43 RCM RCM is basically about answering what are the functions and associated performance standards of the asset in its present operating context? in what ways does it fail to fulfill its functions? what causes each functional failure? what happens when each failure occurs? in what way does each failure matter? what can be done to predict or prevent each failure? what should be done if a suitable proactive task cannot be found? This can be performed through e.g. FMEA and FTA 43

44 Further reading Sherwin, D., (2000), A review of overall models for maintenance management, Journal of Quality in Maintenance Engineering, Vol. 6, pp