Lean Quiz - Dr. Black's Notes Flashcards
What does TPS try to minimize and why?
- people
- inventory
- they don’t depreciate in cost
TPS - Ohno - what did he do?
- reconstructed Job Shop (Mass Production) into manufacturing cells (Lean Production)
- turned final assembly into mixed model
4 horsemen of lean manufacturing
- Cost
- quality
- lead time
- flexibility
Flexibility (one of 4 horsemen of lean manufacturing)
- the capability of a manufacturing system to respond quickly to changes
- volume flex - changes in customer demand
- product flex - changes in product design
- lead time flex - ability to respond to customer orders
Lean Production
- a system design composed of linked cells which can identify and eliminate waste (non-value added activities) to produce perfect goods at demand (pulls) of customers
- want to reduce TPT - to do so, identify and eliminate largest time traps using design rules for lean eng.
Manufacturing System
- a complex arrangement of physical elements characterized by measurable parameters
Flow Shop
- developed/used by Ford
- processes all lined up - sequenced
Job shop
processes collected in departments
Project Shop - fixed position layout
thing being manufactured there is so big that it cant be moved around the shop — civil engineers
Continuous Process Layout
for oils, gases, etc. —- Chemical engineers
Little’s Law
WIP = TPT X PR
Takt Time
TT = 1 / PR
Manufacturing System:
- how to control system
- rules
- boundaries/ constraints of system must be defined
- systems behavior in terms of its response to disturbances from environment must be predictable in terms of its measurable parameters
- rules- laws used to describe how system works and generally require a “theory” which uses equations to describe behavior of systems and its boundaries in terms of input parameters - NO THEORY = NO VIABLE MODEL
History of Factory Designs
- no factories early on - needed factories b/c materials made so strong that man power cant cut - need machines
- 1st is job shop
2nd is flow shop (moving assembly line)
3rd is TPS
Economy of what? for each factory
- job shop - economy of collected processes
- flow shop - economy of scale
- TPS - economy of scope
What Ohno did for Toyota
- changed final assembly into mixed model final assembly line
- flex. and leveling - smoothing of prod. - demand
being smoothed - conveyor driven lines converted to self-balancing sub assembly lines
- cellular manufacturing
- setup reduction / SMED
- integrated quality - 7 tools and 6 sigma
Kanban
Inventory and production control - JIT
Kaizen
continuous improvement
How does Final Assembly operate
- operated with Takt Time and operates on a MO CO MOO basis
Poke Yokes
single machine tools used within built-in devices to check parts
decouplers
device between machines designed to assist standing, walking workers producing parts in manufacturing cells
- SUSTAINS PART FLOW
4 terms of lean engineering: Level
final assemble line (working with forecasts to make this line to level demand)
4 terms of lean eng: Balance
what happens in the sub-assembly and manufacturing cells
4 terms of lean eng: sequence
what happens to stuff when it goes from supply chain to final assembly
4 terms of lean eng: synchronize
if something stops on final assembly, it stops also at sub-assembly. same with starting back up
Takt Time Rule
-level and balance the man. system - make final assembly mixed model - cells produce daily demand - sequence and synchronize
TT = hours available in a day / DD
DD = (# you make/month) / (# days you work/month)
PR = production rate = 1 / TT
TT for final assembly = (Avail hrs/shift)/(available DD/shift)
Self Balancing Sub Assembly Rule (OPF Rule)
- redesign subassembly lines into U-shaped SBSC’s that operate flexibly with OPF to match final assembly needs
- MO CO MOO (OPF with defect prevention
Cell Design Rule (Lean Shop Rule)
MTij <= NCT where NCT = TT(1-allowance)
- the machine tools are single cycle automatics
- Cycle Time = Manual Time + Walking time
- dont add in machining times!
- every part that goes through cell goes through with same CT
SMED Rule
- Shingo
- setup time reduction to where its equal to or less than CT
- SMED - less than 10 minutes
1. determine whats happening now
2. separate internal from external elements (external = you can do while machine is running)
3. shift internal to external
4. eliminate adjustments
Kanban Rule
K = (DD X L + SS) / a - DD is daily demand - L is lead time - SS is safety stock - a is # of units in container - K is # containers in Kanban Length Ka = inventory in a single link - for a link: Ka = L X DD = WIP - for a system: WIP = TPT X PR So sum of lead times for series of links = TPT for system - all the inventory supplying the OPF is in these Kanban lengths - not 0 inventory (its in the kanban lengths - its in the control of the ppl that use it)
What did Ohno do with the cell design rule?
disconnected processing time from the schedule
Toyota’s 5 R’s for reducing pollution
refine reduce reuse recycle retrieve energy
