Title: Tube cutting. Tube bending. Mitering. Welding. Washing
1MSE595LMLean Manufacturing
Chapter 3Flow
2Flow - Definition
- The production system Henry Ford introduced at
his Highland Park, Michigan plant in 1913. - The objective of flow production was to
drastically reduce product throughput time and
human effort through a series of innovations. - Consistently interchangeable parts so that cycle
times could be stable for every job along an
extended line - The line itself
- The reconfiguration of part fabrication tasks so
that machines were lined up in process sequence
with parts flowing quickly and smoothly from
machine to machine - Production control system insuring that the
production rate in parts fabrication matched the
consumption rate of parts in final assembly.
3The World of Batch-and-Queue
- What happens when you go to your doctor?
- Make appointment days ahead
- Arrive on time and wait in waiting room
- Doctor behind schedule
- Referral to a specialist
- Laboratory tests
- Wait for results
- Treatment or medication given
- Trip to pharmacy or to specialist
- Hospitalization whole new disconnected
processes and waiting - What happens when you take a flight?
- What happens when you build a custom home?
- As the customer, you pay for all the waiting and
rework - The creation, ordering, and provision of any good
or any service can be made to flow.
4How to Obtain Flow?
- Think about ways to
- Line up all of the essential steps needed to get
a job done - Obtain a steady, continuous flow
- No wasted motions
- No interruptions
- No batches
- No queues
- Continuous Flow changes everything
- How we work together
- The kinds of tools we devise to help with our
work - The organizations we create to facilitate the
flow - The kinds of careers we pursue
- The nature of business firms and their linkage to
each other - The society
5The Techniques of Flow
- Step 1 Focus on the actual object
- The specific design
- The Specific order
- The product itself
- Step 2 Ignore traditional boundaries of
- Jobs
- Careers
- Functions and
- Firms
- Form lean enterprise removing all obstacles to
the continuous flow - Step 3 Rethink specific work practices and tools
- Eliminate backflows, scrap, and stoppages so that
the design, order, and production of the specific
product can proceed continuously - All three steps must be taken together
6Example From Batch to Flow in BicyclesThe
Design Step
- Marketing department determined a need
- Product engineers design a product to serve the
need - Prototype department built a prototype to test
the design - Tooling department designed tools to make a
high-volume version of the approved prototype - Production engineering figured out how to use the
tools to fabricate the frame and to assemble the
component parts into a completed bike - Purchasing department arranged to buy the
necessary component parts for delivery to the
assembly line once the design was finalized - The design moved from department to department
waiting in the queue - Frequent reworked or secretly reengineered to
deal with incompatibilities between the process
steps
7Example From Batch to Flow in BicyclesDesign
Using The Lean Approach
- Create truly dedicated product teams with all the
skills required to conduct the following in one
room in short period of time - Value specification
- General design
- Detailed engineering
- Purchasing
- Tooling
- Production planning
- Quality Function Deployment (QFD)
decision-making methodology utilizing
standardized work to ensure process
repeatability - Throughput time accurately measured
- Design methodology continuously improved
8Example From Batch to Flow in BicyclesOrder-Taki
ng
- Sales department obtain orders from retailers
- Scheduling department in Operations or
Manufacturing work the production schedules for
the various products - Customers call the Sales department to status
late orders - Sales calls Scheduling
- When customers threaten to cancel orders, Sales
and Scheduling expedite the orders - Sales and Scheduling had been combined in the
early 1990s - Computerized systems make instantaneous order
changes and sometimes electronically transmitted
to the customers
9Example From Batch to Flow in BicyclesOrder-Taki
ng Using the Lean Approach
- Sales and Production Scheduling are core members
of the product team - In a position to plan the sales campaign as the
product design is being developed - Sale with a clear eye to the capabilities of the
production system so that both orders and the
product can flow smoothly from sale to delivery - No stoppages in the production system
- Products are built to order
- Only few hours elapse between the first operation
on raw materials and shipment of the finished
item - Orders can be sought and accepted with clear and
precise knowledge of the systems capabilities - There is no expediting!
10Takt Time
- Precisely synchronizes the rate of production to
the rate of sales to customers - Takt Time Calculation Example
- Customers are placing orders at the rate of
48/day - Bike factory works a single eight-hour shift
- Takt time adjusted as orders increase or decrease
over time - The production slots created by the Takt Time are
clearly posted on whiteboard or electronic
displays (andon boards) - Lean technique transparency or visual control
everyone can see where production stands at every
moment
11Takt Time
12Key Points About Takt Time
13Example From Batch to Flow in BicyclesProduction
- Historic practice was to differentiate production
activities by type and to create departments for
each type of activity. - Frame and handle bars
- Tube cutting
- Tube bending
- Mitering
- Welding
- Washing
- Painting
- Final Assembly of complete bike
- Over time, higher speed machines with higher
levels of automation were developed for cutting,
bending, welding, and painting - Assembly lines to assemble a mix of high-volume
models - Large batches made before changing over to run
the next part - Large inventory
14Bicycle Plant Layout and Flow
15 16Continuous Flow Production
- Remember!
- Make It Flow
- Feed the Flow
- Link the Flow
17Continuous Flow Production
18Steady Velocity
2 WEEKS!
When do we get our Parts?
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23Connected Lines
24Layout change
Before
GearHobbing
ManualDeburring
ToothChamfer
HoleBoring
Gear Shaving
In
Out
25Summary of Benefits
- Work flow levels are reduced and progress is
visible at a glance - The ability to cross train is enhanced
- Work team members take ownership of full process
and can help each other - Quick problem identification and feedback
- Reduced Cycle Time
- Improved quality through cycle of learning
- Information flow and decision making enhanced
- Value-added ratio improved
- Reduces transportation waste
- Reduces material handling
- Helps to identify root causes of quality problems
- Allows for equipment dedication
- Drives set-up times down
26Rules for Kanban Systems
- 1) Pull from the downstream process (or
customer) drives the system. - 2) All product or inventory is under kanban
control. - 3) Only an empty kanban authorizes production.
- 4) Never pass a known defect downstream.
- 5) Use gradual kanban reductions to drive
improvement.
27Purpose of a Kanban System
1) Authorize production 2) Authorize
movement. 3) Limits amount of inventory in the
system. 4) A tool for driving continuous
improvement.
28Kanban
Is a signal that
- The signal can be a
- Card
- Square
- Box
- Pigeon hole
- Light
- Etc.
- Electronic Signal
- Racks
- Shopping Carts
- MRK ( Manufacturing Ready Kit)
- Drives continuous improvement
29How Many Kanbans?
30Example
31Pull Production System
- Definition
- A customer driven system that produces and moves
a product/service only when the customer needs it.
Customer Pulls
Kanban 1
Kanban 2
Kanban 3
Work Center A
Work Center B
Work Flow
32Kanban Example
Condo-ban!!
Who is full?
Who needs work?
33Kanban
Unit in build
Units ready for calibration
34SMT Kanban
35Kanban Light (More Work)
364-754 MRKManufacturing Ready Kit The empty kit
signals for replenishment
374-754 MRK
38Homework Assignment
- Questions
- Explain what is meant by Continuous Flow
Production - What is Takt Time? What is Takt Rate? Why is it
important to know them? - Read Lean Thinking Chapter 4 - Pull
- Pages 67 - 89
39Questions? Comments?