This is lean Flashcards
What are the 2 types of efficiency?
1) resource efficiency
- focus: resources
- utilize resources and maximize capacity utilization (value adding time/available capacity)
2) flow efficiency
- focus: flow units
- fulfill needs (value adding time/ throughput time)
What is a process?
Sequence of activities designed to fulfill needs
What are examples of flow units?
information, material, people
What is the difference between value-adding time and non-value adding time?
when is value created for the customer?
looking at non-value adding time is primary way of increasing flow efficiency
Faster is not always better!!
What are direct vs indirect needs?
- direct - outcome
- indirect - experience
What determines the share of direct and indirect needs?
nature of service, occasions, people
What is little’s law?
Throughput time = flow units in process*cycle time
–> consider people in queue and speed of how the queue is moving
What is the law of bottlenecks?
before bottleneck - pile up
after bottleneck - waiting time
bottleneck determines speed
What are the conditions of bottlenecks?
1) serial dependence
2) variation
What is the VUT relationship?
Variation, utilization & throughput- time
The more variation the longer your throughput time will be at a given utilization
What are the 4 dimensions of the efficiency matrix?
(horizontal - flow efficiency; vertical - resource efficiency)
Wasteland, Efficient island, The perfect state, Efficient ocean
What is the efficiency frontier?
In the efficiency matrix - variation decreases the possibility to reach perfect state (star)
What is the efficiency paradox?
Which form of efficiency should we prioritize?
What are the effects of resource efficiency?
- throughput time - long
- number of units - many
- restarts - many
What are the effects of flow efficiency?
- throughput time - short
- number of units - few
- restarts - few
What are consequent effects when focusing on resource efficiency?
- long throughput time –> trigger other effects
- more flow units –> notion of inventory
- more restarts –> call center
When focusing on resource efficiency, what can happen?
Secondary needs - needs that customer has and you want to fulfill them but you engage in superfulous work
What is superfulous work?
- wasteful and not wasteful at the same time
- we create problems ourselves we need to fix
What is the efficiency paradox?
by not focusing on utilizing capacity, we free up capacity (just because you are busy, doesn’t mean you are adding value)
What is lean operations strategy?
move right and up (first focus on flow efficiency, then on resource efficiency)
you notice different problems in process –> address problems –> remove superfulous work –> increase resource efficiency
Why is continuous improvement important?
static goal - once you reach the goal, you’re done
dynamic goal - constant improvement (i.e. Toyota)
