Cours Flashcards
What is lean three basic elements
Demand driven
Focused on waste reduction
Culture of continuous improvement
Terms related to lean operation : Muda : ? Pull system : ? Kanban : ? Heijunka : ? Kaizen : ? Jidoka : ? Team concept : ?
Terms related to lean operation :
?: Waste and inneficiency
?: Replacing material or parts based on demand
?: Manual system that signal the need for parts of material
?: Workload leveling ( variation reduction)
?:Continuous improvement of the system
?: Quality at the source ( automation)
?: Use small team to improve
Ultimate goal of lean
Achieve a system that matches supply to customer demand in a smooth and uninterrupted flow
Sub Goal of lean
1 ELIMINATE DISRUPTION : such as poor quality equipement, late delivery , change in schedule etc.
2 MAKE THE SYSTEM FLEXIBLE : Robust enough to handle a mix of product on a daily basis and handle change in level output
3 ELIMINATE WASTE, in particular excess of inventory
Waste = unproductive ressources
7 wastes :
1 Inventory 2 overproduction 3 Waiting time 4 Unnecessary transporting 5 Processing waste( unnecessary production steps) 6 inneficient work methods 7 product defect
Kaizen philosophy :
Kai= change Zen = Good
10 steps
1 Waste is the ennemy, need to get the hands dirty to eliminate it
2 Improvement gradualy and continuously ( no big change)
3 Everyone should be involved
4 Kaizen is build on cheap strategy, no technology, no consultant
5 Focus attention where value is created
6 Can be applied everywhere
7 Based on visual and transparent system, problem and waste must be visible to all
8 It is process oriented
9Main effort of improvement must be new work style
10 learning while doing.
Building blocks ( after sub goal of lean) 4 steps
1 product design
2 Process design
3 personnel/ organizational elements
4 Manufacturing planning and control
1 Product design ( 4 elements)
1 Standard part: fewer part to deal with , less training time, less cost and economy of scales. Process can be standardized
2 Modular design : Modules are cluster parts treated as a single unit. reduces number of part to deal with, simplify assembly, purchasing training etc.
3 highly capable Production system with quality built in :
Poor quality creates major disruption . Avoid shutdown and solve problems fast
4:Concurrent engineering: Engineering hanges can be very disruptive and this allow to counter that
1.1 Process design (8 steps)
1 Small lot sizes 2 setup time reduction 3Manufacturing cells 4 quality improvement 5Production flexibility 6 A balanced system 7 little inventory storage 8 Fail-safe methods
1.1.1 Process design - Small lot sizes
6 advantages and model
1 reduced inventory, lower carrying costs 2 Less space for inventory 3 Less rework if defects occur 4 INcrease visibility of problem 5 increase production flexibility 6 Increase ease of balancing operation
Model : Smal lot sizes model AAA BBB CCC AAA BBB CCC AAA BBB CCC Normal model AAAAAAAAA BBBBBBBBB CCCCCCCCC
1.1.2Process design-setup time reduction ( SMED) 4 points
- First categorizing changeover activitiers as either internal or external activitied
- External activities are those that do not involve stopping the maching ( fex finding a tool for the setup) so they do not affect changeover time
- internal activitied can be done while a machine is stopped( placing new tool)
- to ahcieve quick changeover convert as many internal activities as possible to external activity and streamline the remaning internal activited
SMED framework
1er stage Batch A - initial setup - batch b 2 Identify external and internal setup Batch A - external-internal - batch b 3 separate Batch A -internal - batch B - external
1.1.3Process design manufacturing cells
(Cell contain the macihnes and tools needed to process families of parts having similar processing rtequirements. In essence the cells are highly specialized and efficient productiron center 3 parts
Reducezd changeover times
high utilization of equipement
ease of training operators
1.1.4Process design - quality improvement
The quality defects during the process can disrupt the orderly flow of work
Lean production systems minimize defect through the use of autonomation (jidoka) whiuch involves the automatic detection of dfefects during production
- interligent automation
- automation with human intervention
Comme a toyota
1.1.5Process design - Work flexibility
guidelines for increasing prod flexibility ( 6 points)
1 Reduce changeover time 2 use maintenance toi reduce breakdowns 3 cross train workers 4 use many small unites of capacity 5 Use online buffers 6 REserve capacity for important customers
1.1.6 Process design - a balanced system
Time needed for work assigned to each workstation must be less than or equal to the cycle time ( task time )
3 procedures
1 Determine the net time per shift by substracting any nonproductive time from total shift tiome
2 if there is more than one shift per day multiply it to have the net available time per day
3 compute tyasktime byu dividing the net available time by demand
Total time - rest breaks - lunch = x
X * nombre de shift = Y
Y / daily demand = time per cycle
1.1.7Process design - inventory strorage
Lean systems are designed to ?
Minimize inventory storage because it is a waste
1.1.8Process design fail-safe-methods
failsafing refers to
Building safeguards into a process to reduce or eliminate the potential for erros during a process
poka-yoke = mistake proofing
Personnel/ organizationnal elements
5 elements of personnel organization
1 worker as assets ( well trained and more authority they are expected to doi more
2Cross trained workers - able to help one others and replace colleagues
3 Continous improvement
4 Cost accounting ( all cost incurred in an activity are colected classsified and recorder )
5 Leadership ( managers are facilitator not order giver
2 Manufacturing planning and control 7 elements
1 Level loading 2 Pull system 3 visual systems 4 limited work in process 5 close vendor relation ship 6 reduced transaction processing 7 preventive maintenance and housekeeping
2.1 Manufacturing planning and control level loading Production leveling (Production smoothing or heijunka ) is a technique for reducing mura ( unevenness) which reduces muda ( waste) : 2 points
Batching : Batching : producing large lots of products without taking into account the fluctuation of customers demand creates inventory
Heijunka : avoiding the inefficiences of manufacturing in large lots by putting the production process closer in line whith customer demand
2.2 Manufacturing planning control pull system
Just in time, work after the demand by the customer
2.3 Manufacturing planning Control visual system
TO quickly communicate inforemation to people ( like tool shadow board)
2.4 Manufacturing planning controll limited work in process
Amount of WIP in a production system can yield substancial benefits ( 3 )
1 One is lower carrying cost due to lower wip inventory
2 Another i the increased flexibility that would be lkost if there were large amounts of wip in the system
3 Low WIP aids scheduling and saves costs if there are desing changes
2.5 manufacturing planning & control Controll close vendor relationships
Under Just in time, purchasing reduce their list of supliers to crteate close relationship with them. Finding local vendors shorten the lead time deliveries and variability.
Or use whole saller suppliers ( suppliers of suppliers) for complex compagnies
2.6 manufacturing planning and control - reduced transaction processing ( 4 points)
1 LOGISTICAL TRANSACTIONS ordering execution and confirmation of materials transported. Related costs cover. data entry and data processing
2 BALANCING TRANSACTIONS include forecasting production planning production control procurement scheduling etc…
3 QUALITY TRANSACTION include determinung and communicating specification ( rework, delay) and external failure
4 CHANGE TRANSACTION engineering changes
2.7 manufacturing planning and control - Preventive maintenance and housekeeping
Preventive maintenance - Maintening equipement in good operating condition and replace them before they fail
Housekeeping - maintaining a clean workspace
3.1 Transitioning to a lean system - planning a succesful conversion ( 7 points)
1 make sure that managment knows it will cost , how long and the results expected
2 decide which parts need more efforts
3 make sure workers are fully informed about lead, reassure workers about job secure
4 Begin by trying to reduce set up times with current system and make the worker eliminate the problems
5Gradually convert operations beginning at the end of the process and working backward
6 start by narrowing the list of vendors and take those that want the lean philosophy. Good relation with them
7 Be prepared to encounter obstacles to conversion
3.2 Transitioning to a lean system obstacles to convertion(4 points)
1 Management may not be totally commited 2 workers may resist because of responsability and stress 3 Hard to change culture of organization 4 Suppliers mlay resist - no willing, or don't like long term commitement - don't like small deliveries - burden of control from them - engineering changes from the buyers
Lean Services ( 6 points)
1 ELIMINATE WASTES ( errors and duplicate works)
2 ELIMINATE DISRUPTION ( avoid having workers who are servicing customers)
3 MAKE the system flexible ( WOrk can handle more variety)
4 Miniminze work ion process ( order witing , call and mail not answered etc)
5 reduce setup times and processing times
6 simplify the process
