Lean Systems Flashcards
TPS / Lean Systems
strive for removing waste and having no extra space (JIT)
developed from Toyota
- background
- current condition
- goal statement
- root-cause analysis
- counter measures
- effect confirmation
- follow-up actions
Flow!
“lean” = no secrets
GMC Absenteeism decreased
- Toyota Production System based on two original ideas: eliminate waste and respect people
Running a Lean Factory
GM Plant (then) 1980s
- many indirect workers
- 2 weeks inventory
- overhead housekeeping
- many defectives/mistakes
- busiest place: repair centers
- low morale (45%)
- slow pace
Toyota Plant
- few indirect workers
- 2 hrs inventory
- work-teams housekeeping
- few but treasure defectives/mistakes
- non-existent repair centers
- high morale
- fast pace
What is “Value Stream”?
all the actions (both value added and non-value added) currently required to bring a product through the main flows (understanding flows) essential to every product
What is “Lean”?
do all activities add value to a customer would pay for? if not, there is “waste” and not yet “lean
Five Lean Principles
- define value from a customer perspective
- map (“see”) the value stream (VSM)
- ensure (create) processes flow simply, smoothly, and without waste
- establish pull using customer demand
- strive for excellence with continuous improvement
What is “Waste”?
Defects
Overproduction
Waiting
Not using people properly (talent)
Transportation (products and materials)
Inventory
Motion (people)
Extra processing (overprocessing)
Lean Tool: 5S
- sort (spring cleaning)
- straighten (a place for everything, shadow board)
- shine (clean, inspect, and care)
- standardize (sort-straighten-shine everywhere)
- sustain (a habit, a fabric of life)
What is “Value Stream Mapping”
VSM current slate
a widely used qualitative lean tool aimed at eliminating waste or muda
“where is the waste?”
go to the Gemba, observe work being done in real time
Common VSM Metrics
- Takt Time (TT): Available time per day / Demand per day
cycle time or “rhythm” of demand - Processing Time (PT): given or measured (how long for each and every item)
“time each item takes” - Cycle Team (CT): “rate”, Processing Time / Resources (how many at a time)
“rate of flow” or “process capacity”
Utilization (Util): Cycle Time / Takt Time x 100%
“capacity” related to demand
- Days of Inventory (triangle): Inventory / Demand per day
DOI translates # of items into “time”
Waste Elimination
lean is a mindset applicable across industries about relentless simplification and elimination of waste. lean embodies TQM ideas, but focuses on eliminating waste
The optimization of value adding activities and elimination of non-value adding activities that are part of the value stream.
Value Stream Mapping (VSM)
a tool for “seeing” a process with four steps: identify product family, draw a current state map, determine a future state map, create an implementation plan
5 elements: customer info, supplier info, main fulfillment process, info and production control, timeline calculation (VSM differs from process mapping by focusing on value creation opportunities and constraints instead of activities)
key calculations: TT, PT, CT, DOI, LT, Util (TT and DOI “index” calculations to daily demand enable us to relate how fast and how long it takes to meet customer requirements)
Lean production
Integrated activities designed to achieve high-volume, high-quality production using minimal inventories of raw materials, work-in-process, and finished goods. In the context of supply chains, it refers to a focus on eliminating as much waste as possible
Customer value
In the context of lean production, something for which the customer is willing to pay
Waste definition
Anything that does not add value from the customer’s perspective
Current State/Future State
Value stream mapping is a two-part process- first depicting the “___________” of the process and second a possible “future state.”
Value stream mapping (VSM) is a two-part process. What are those two parts? Check all that apply.
Multiple select question.
- future state
- current state
- past state
- alternative states
Kaizen
continuous improvement
takt time
available time per day / demand per day
the cycle time for rhythm of demand “how long does each cookie bake in the oven”
processing time
given or measured (how long for each and every item)
PT = “time each item takes” aka we’re adding value to the item
cycle time
processing time / resources (how many at a time)
CT is the rate of flow or process capacity
“how many cookies can you bake at the same time?”
utilization
cycle time / takt time
utilization is “capacity” related to demand
days of inventory
inventory / demand per day
DOI = # items into “time”
FTE =
the number of people x % of time they work
The final goal of VSM metrics
TT > CT
Manufacturing process current state map
product family -> current state -> future state -> implementation
