Transcript LEAN system
LEAN system & Six Sigma Lecture 6. Value That customer is willing to pay That changes products color, function, shape, other attributes so that the product is getting closer to the customers requirements That we do right at first time Wastes Those processes which directly do not create value for customers (muda, mura, muri) : that are not necessary, and must be eliminated That are necessary, because these are supporting value-add processes, cannot be eliminated (like transporting) Muda – 7 wastes of lean Mura – not leveled workflow Muri – overloading of workers and assets Lean thinking Operation Traditional improvement Lean improvement Non value-add process Value-add process Supporting goals A balanced system, smooth, rapid flow of materials and/or work Supporting goals: Eliminate disruption Make the system flexible eliminate waste, especially exess inventory There are 7 wastes in LEAN (TIMWOOD): Inventory Overproduction Waiting Unnecessary transportation Processing waste Inefficient work methods Defects Tools of LEAN relating to quality Quality improvement - Jidoka Autonomation – automatic detection of defects during production. It consist two activities: One for detecting defects when they occure Another for stopping production to correct the cuase of defects. Fail- Safe methods – Poka Yoke Methods: The contact method identifies product defects by testing the product's shape, size, color, or other physical attributes. The fixed-value (or constant number) method alerts the operator if a certain number of movements are not made. The motion-step (or sequence) method determines whether the prescribed steps of the process have been followed. Kanban Production Control System Kanban is the Japanese word meaning “signal” or “visible record” Sign to produce Sign to transport Paperless production control system Preventive maintenance and housekeeping 5S Sort –decide which item is needed Straighten – needed items can be assessed quickly Sweep – clean workplace Standardize – use standard intructions Self discipline – make sure that employees understand the need for uncluttered workplace Six Sigma 1 σ – 691 462 ppm 2 σ – 308 538 ppm 3 σ – 66 807 ppm 4 σ – 6 210 ppm 3 sigma process 5 σ – 233 ppm 1 sigma process 6 σ – 3,4 ppm USL LSL 3σ 3σ 5% is out of limits! USL LSL 6σ 6σ DMAIC Define Measure Analyze Improve Control PDCA Plan Do Check Act Six Sigma Project Risk Worksheet Six Sigma Project Return Project Risk and Return matrix Rwturn factor 100 90 80 STARS ? LOW-HANGING FRIUTS DOGS 70 60 50 40 30 20 10 0 0 10 20 30 40 50 60 70 80 90 100 Risk factor XY matrix Inputs and outputs Determine which input is the most important to focus on TAGUCHI DESIGN EXPERIMENT (DOE) Robust Design – select technology Parameter Design – set parameters which affect quality Tolerance Design – improve the quality if parameter design doesn’t work Definition of quality – loss to society QLF (Qualtiy Loss Function) L=K*V2 K – constant, and V2- mean squared dviation from target value K=C/T2 C - unit repair cost T – tolerance interval LSL Target value USL Exercise - QLF Suppose the cost to repair a radiator on an automobile is $200. Compute the QLF for losses incurred as a result of a deviation from target setting where a tolerance of 6±0,5 mm is required and the mean squared deviation from target is (1/6)2. Solution: K=200/0,52=800 L=K*V2=800*(1/6)2=$22,22/unit TAGUCHI PROCESS 1. Problem identification 2. Brainstorming session identify factors, its settings, interactions, Identify objectives Offline experimentation (number of replications) Experimentation The less is better Nominal is best The more is the better Experimental design Control factor Noise factor Orthogonal array (determined by the number of factors and levels) Record the result Compute average performance for each factor Showing the best outcomes Analysis (which level of each factor is the proper one) Confirming experiment (validate results) Thank you for your attention!