The Book of Value Stream Maps II

Transcription

1 The Book of Value Stream Maps II Plant Level Maps for Process Industries Solutions to common value stream mapping problems with example maps Supplier Process Customer By: Dilesh Patel, Herman Ranpuria, Jayesh Shah & Jonathan Fournier

2 Objectives of this book: To identify common problems in value stream mapping at the plant level, and show how you can solve them to better support a lean deployment. To provide mapping, calculation, and charting support that complements the workbooks Learning to See, Creating Continuous Flow, Making Materials Flow, and Creating Level Pull from the Lean Enterprise Institute. Recommended Prerequisites: A basic understanding of the VSM methodology through training or a book such as Learning To See (John Shook and Mike Rother).

3 The Book of Value Stream Maps II Plant Level Maps for Processing Industries Solutions to common value stream mapping problems with example maps By Dilesh Patel, Herman Ranpuria, Jayesh Shah & Jonathan Fournier Copyright 3 The evsm Group 7577 Central Parke Boulevard, Suite 36 Mason, OH 454 Tel: All rights to text and illustration reserved by The evsm Group

4 The Book of Value Stream Maps II Plant Level Maps for Processing Industries

5 PART I: LEAN & VSM OVERVIEW 3 Lean and VSM A Pictorial Review 6 Value Stream Improvement 8 Levels and Waste 3 Muda, Mura, Muri 5 Visualizing Waste 7 Capacity, Lead, and Cost 8 PART II: MAPPING Q&A 3 VSM Concepts for Process Industries 6 Process Industries VSM Terms 8 A Simple Processing VSM 37 Capacity Q&A 4 Lead Q&A 5 Cost Q&A 56 PART III: VSM Exercises 63 Appendix 83 Appendix A: Mapping Q&A 85 References 86 Index 88

6 Lean and VSM A Pictorial Review Product family Current-state drawing Future-state drawing Work plan & implementation Process level Single plant (door to door) Multiple plants Across companies. Value stream maps help visualize the waste and can be drawn at different levels from an individual process to an enterprise map across plants or even companies. This book focuses on plant level maps.. Specifying Value Precisely specify value by specific product.. Identify the Value Stream Identify the value stream for each product. 3. Flow Make value flow without interruptions. 4. Pull Let the customer pull value from the producer. 5. Perfection Pursue perfection.. The book Lean Thinking introduced us to the 5 Lean Principles, the concept of product value streams, flow, and pull. Non-Value Added (Waste) Value Added Non-Value Added but Necessary Waste Removal Waste Value Added Non-Value Added but Necessary 3. Lean thinking removes waste from the value stream. Work components can be thought of as value added, non-value added but necessary, and as waste. Lean is a continuous improvement methodology that reduces the waste and questions why any non-value added work is truly necessary. 6

7 Long Set ups Poor Housekeeping Mixed Materials Delay in Delivery Water Level Rework Machine Breakdowns = Amount Generating Defective Products 4. A useful analogy links inventory to the water level in a river. The rocks in the river represent the forms of waste. See the detailed chart later in this section. Muda 5. These are three system level causes of wasteful activities, muda, mura, and muri. See the detailed chart later in this section. Mura Muri Defects Waiting Capacity Excess Excess Motion 6. The Toyota Production System identifies 7 types Cost of waste and value stream maps link these to the metrics of Lead, Transportation Over Production Capacity, and Cost. See the detailed chart later in this section. Lead Over Processing PART I LEAN & VSM OVERVIEW 7

8 4 A Activity Lead A3 Wk A4 Cycle Qty Per Cycle Activity Sec A A6 Cycle Qty Per Cycle.75 5 Sec Stations Stn A3 Blanks.6 A5 Molded Blanks A7 A7 Drilled Blanks.44 3 A8 Cycle Qty Per Cycle Legend 6 Non Value Added Value Added Sec A A Customer Demand Z Lead Total Value Added Value Added Percent Takt all % Value Stream Improvement Process Wall Sketch Select Product Family Start from a wall map developed with the group involved in the value stream Sustain improvements Future State becomes Current State Improvement cycle continues Plan & Implement Improvements U-shape Layout for Assembly Cell Replace D4 Drilling Station Milling Area 5S New lighting in Hanger 5 Create Future State Replace D7 Drilling Station Daily Order Control Activity Weekly Order Group Value Stream Mapping Event ATLAS Warehouse Customer Blanks Mold Handles Molded Blanks Sharpen Drilled Blanks Assemble Scissors Summary Lead Summary Create a future state map based on the improvement projects selected and create an implementation plan

9 Capture Map Analyze and Visualize Sketch over digital picture of wall map Sec/ Cycle / Takt Chart Activity Takt Cycle Per Unit A4 A6 A8 Analyze the map to understand opportunity for waste elimination, flow implementation, and pull (not push) production Brainstorm Improvements Prioritize Improvements Impact On Value I II Kaizen Impact Matrix 3 III 4 IV Brainstorm and add improvement ideas using kaizen starbursts Perform Root Cause analysis (5 Why s) Difficulty Of Implementation Look at impact (on key metrics) and difficulty of implementation to prioritize improvement projects 6 8 PART I LEAN & VSM OVERVIEW

10 Defects Waiting Capacity Excess Excess Motion Cost Transportation Over Production Lead Over Processin g Primary linkages between Capacity, Lead, Cost and the wastes in the value stream 6

11 Visualizing Waste Lean manufacturing is concerned with visualizing and eliminating waste in the value stream in a prioritized fashion. The diagram to the left shows the classic seven wastes and how they relate to the summary metrics of Capacity, Lead and Cost. An eighth waste not shown is the underutilization of people in terms of their knowledge, skills, and abilities. While all of the wastes do relate to each other and to the three metrics above, we have noted the primary linkages that we see frequently when we look at value streams at the beginning of a lean deployment. We invite you to select some of the linkages and think about examples of them in your own environment. In visualizing the waste in the value stream: Look at the activities on the value stream to see which are truly necessary and where sections of the value stream can be isolated and optimized. Use the Lead as a driving metric to improve the processes in the current value stream map. The stepped timeline at the bottom of the map is a useful tool in understanding the factors contributing to Lead s. Use a Cycle /Takt chart to better understand Capacity and see which Capacity losses are important to reduce and if there is opportunity for load-balancing. Understand the incremental cost of each step (including Carrying Costs) in the value stream. Use Cost as a driving metric to improve the target cost of the products being created by the value stream. Identify opportunities for improvement. PART I LEAN & VSM OVERVIEW 7

12 VSM Concepts for Process Industries Weight Balance Whole Grain By-Product Hay Demand = 5 Cases/ Sep : 8% Co-Products Grain Farm Grain Separation Sep : % Mix : 95% Refining & Mixing Mixed Grain Step Yield = 98% Scrap = 4% Whole Grain Demand = Cases/ Demand Local Units Mix Quinoa Grain Mix : 5% This map shows the key concepts encountered during the creation of value stream maps for the processing industry. Weight Balance ties Demand for all the raw materials, Work In Process, and process steps to the finished product(s) through a central measure of weight. As the grain moves from the farm through the processing steps, a Local Unit of weight measure is used at each step. This can then be tied back to the overall customer demand. The weight balance must also take into account material losses/gains through each step because of Scrap or Step Yield losses. The concept of Co-Products is illustrated by the creation of two final products for the line on the map: whole grain and mixed grain. Each product has a separate demand, but they are produced simultaneously. By contrast, the hay is a By-Product as it is a low value result of the production of the grains. There may be a demand for it, but actual production may be in excess of the demand because production is driven by the primary products. The separation of the hay from the grain by percentage weight is noted on the map and is used in the weight balance calculations. 6

13 Key concepts for process industry maps: Weight Balance: The tracking of weight begins with customer demand and moves upstream. The weight balance equations account for ingredients in different proportions and for losses due to Scrap and Step Yield. The tracking also enables use of local weight units (for convenience) at the different steps. The weight balance calculations show how much production is needed at each step. Local Units: Each step along the process can use local units of weight for convenience. The operators of the Grain Reaping step can define their output in terms of tons, the operators of the Refining & Mixing step can define their product in terms of bags, and the demand for Whole Grain can be in terms of cases. Tons, bags, and cases all constitute different measures of weight. By-Product: This is created through the manufacturing of the primary products. The hay is created through fulfilling the customer demand for Whole Grain and Mixed Grain. It may have a low value. Co-Product: Two or more products created simultaneously through similar processes and inventories. Demand: The amount of product requested by customers. This concept is seen for Whole Grain as 5 cases/day and for Mixed Grain as cases/day. The weight balance translates this to Activity Demand at any point along the value stream. Mix: The amount of product used from two different inventories in a process. As seen in the Refining & Mixing step, 5% of Quinoa Grain is mixed with 95% of Whole Grain to produce Mixed Grain. Step Yield Percent: Accounts for gains/losses that are natural outcomes of a process, but not losses due to Scrap etc. PART II MAPPING Q&A 7

14 Question Index: Capacity, Lead, & Cost How do I allocate cost for byproducts? (Page 56 ) How do I convert production time to calendar time? (Page 5 ) By-Product Sep : 8% Hay What is the demand for an activity with several products? (Page 4 ) Grain Farm Grain Separation Sep : % Step Yield = 98% Scrap = 4% Whole Grain How does scrap impact capacity? (Page 4 ) How does scrap affect my unit cost? (Page 57 ) 34

15 How to Use This Index: This index shows popular questions organized in the relevant area of a VSM. Detailed answers appear on the listed corresponding pages. Capacity Questions Lead Questions Cost Questions How is NVA time calculated for inventory? (Page 5 ) Whole Grain Demand = 5 kg/ What are the costs associated with having inventory? (Page 56 ) Mix : 95% Refining & Mixing Mixed Grain Demand =, kg/ How do I model several ingredients? (Page 4 ) Mix Quinoa Grain Mix : 5% How do I determine what is my lead time? (Page 5 ) PART II MAPPING Q&A 35

16 Figure : Visualizing Capacity Using Charts DIW% % A3 Muggle Factory A5 Sugar = Bin DIW% 75 % Supplier Lead 5 Weight Per Requirement s of LO Q Week 6.88 A7 DIW% % A8 Make Slurry Stamp beans We have added Setup time here DIW% % DIW% 5 % Weight Per Cycle Rate Process Lead = 6. 5 Step Yield % Weight Per Cycle Rate Process Lead = 5 3 Step Yield 95 % A4 Various A6 Gelatin = Bin Utilization 9.67 % Setups Per Setup.5 StUp StUp Utilization 98.5 % Supplier Lead 9 Weight Per Requirement s of Utilization LO Q Week 5.6 Activities with Utilization above 9% indicate possible bottlenecks 8 % 7 6 Utilizati on 5 Week A7 A8 A9 Make Slurry Stamp beans Box Packaging Utilization Legend The utilization chart can also identify Capacity constraints. Utilization under 9% is desired 44

17 W% % A9 Box Packaging Weight Per Cycle Rate Process Lead = Case 6 Step Yield % Utilization 8.87 % Scrap 5. % Loss in Capacity due to Setup time DIW% % A3 FG = Case Weight Per Requirement s of A3 LO Q Week.7 DIW% % Truck = Case Weight Per Transport Qty Transport Transport Distance s of Supply 7.33 The Cycle Rate / Takt Rate chart is the primary means of visualizing Capacity 5 Mile. Cycle Rate / Takt Rate Chart DIW% % A3 Truckshop Distributors A33 Demand Weight Takt Rate = Case Summary Total Lead 9.6 Material Lead Information Lead. Total Value Added 9. Value Added Percent. % Loss in Capacity due to Scrap Activities with Cycle Rate at or below Takt Rate indicate possible bottlenecks / Effective Output Cycle Rate Activity Output Takt Rate Scrap Rate Loss Setup Rate Loss EOCR Cycle Rate above Takt Rate indicate sufficient Capacity A7 A8 A9 Legend Make Slurry Stamp beans Box Packaging PART II MAPPING Q&A 45