Upload
abhinav-pandey
View
706
Download
1
Tags:
Embed Size (px)
Citation preview
Operations Operations ManagementManagement
Just-in-Time SystemsJust-in-Time SystemsSupplement 12Supplement 12
Waste is ‘anything other than the minimum amount of equipment, materials, parts, space, and worker’s time, which are absolutely essential to add value to the product.’
— Shoichiro Toyoda President, Toyota
© 1995 Corel Corp.
Introductory QuotationIntroductory Quotation
Management philosophy of continuous and forced problem solving
Supplies and components are ‘pulled’ through system to arrive where they are needed when they are needed.
What is Just-in-Time?What is Just-in-Time?
Attacks waste Anything not adding value to the product
From the customer’s perspective
Exposes problems and bottlenecks caused by variability Deviation from optimum
Achieves streamlined production By reducing inventory
What Does Just-in-Time Do?What Does Just-in-Time Do?
Overproduction Waiting Transportation Inefficient processing Inventory Unnecessary motion Product defects
© 1995 Corel Corp.
Types of WasteTypes of Waste
Variability Occurs BecauseVariability Occurs Because
Employees, machines, and suppliers produce units that do not conform to standards, are late, or are not the proper quantity
Engineering drawings or specifications are inaccurate
Production personnel try to produce before drawings or specifications are complete
Customer demands are unknown
Push versus PullPush versus Pull
Push system: material is pushed into downstream workstations regardless of whether resources are available
Pull system: material is pulled to a workstation just as it is needed
Suppliers reduced number of vendors supportive supplier relationships quality deliveries on time
Layout work-cell layouts with testing at each step of the process group technology movable, changeable, flexible machinery high level of workplace organization and neatness reduced space for inventory delivery direct to work areas
JIT Contribution to Competitive JIT Contribution to Competitive Advantage - continuedAdvantage - continued
Inventory small lot sizes low setup times specialized bins for holding set number of parts
Scheduling zero deviation from schedules level schedules suppliers informed of schedules Kanban techniques
JIT Contribution to Competitive JIT Contribution to Competitive Advantage - continuedAdvantage - continued
JIT Contribution to Competitive JIT Contribution to Competitive Advantage - continuedAdvantage - continued
Preventive Maintenance scheduled daily routine operator involvement
Quality Production statistical process control quality by suppliers quality within firm
JIT Contribution to Competitive JIT Contribution to Competitive Advantage - continuedAdvantage - continued
Employee Empowerment empowered and cross-trained employees few job classifications to ensure flexibility of
employees training support
Commitment support of management, employees, and suppliers
ResultsResults Queue and delay reduction, speeds throughput, frees
assets, and wins orders Quality improvement, reduces waste and wins orders Cost reductions, increases margin or reduces selling
price Variability reductions in the workplace, reduces
waste and wins orders Rework reduction, reduces waste and wins orders
YieldingYielding
Faster response to the customer and higher quality
A competitive advantage!
SuppliersSuppliers
Preventive Preventive MaintenanceMaintenance
LayoutLayout
InventoryInventory
SchedulingScheduling
QualityQuality
Employee Employee EmpowermentEmpowerment
JIT
Just-in-TimeJust-in-TimeSuccess FactorsSuccess Factors
Incoming material and finished goods involve waste
Buyer and supplier form JIT partnerships JIT partnerships eliminate
Unnecessary activities In-plant inventory In-transit inventory Poor suppliers
SuppliersSuppliers
Goals of JIT partnershipsGoals of JIT partnerships
Elimination of unnecessary activitiesElimination of in-plant inventoryElimination of in-transit inventoryElimination of poor suppliers
Streamlined ProductionStreamlined Production
Flow with JIT
Traditional Flow
CustomersSuppliers
Customers
Suppliers
Production Process (stream of water)
Inventory (stagnant ponds) Material
(water in stream)
JIT objective: Reduce movement of people and material Movement is waste!
JIT requires Work cells for product families Moveable or changeable machines Short distances Little space for inventory Delivery directly to work areas
LayoutLayout
Traditional: inventory exists in case problems arise
JIT objective: Eliminate inventory JIT requires
Small lot sizes Low setup time Containers for fixed number of parts
JIT inventory: Minimum inventory to keep system running
InventoryInventory
Involves timing of operations JIT requires
Communicating schedules to suppliers Level schedules Freezing part of schedule nearest due date Small lots Kanban techniques
SchedulingScheduling
Japanese word for card Pronounced ‘kahn-bahn’ (not ‘can-ban’)
Authorizes production from downstream operations ‘Pulls’ material through plant
May be a card, flag, verbal signal etc. Used often with fixed-size containers
Add or remove containers to change production rate
KanbanKanban
Figure S12.5Figure S12.5
JIT: A Pull SystemJIT: A Pull System
In a push system, such as an MRP system, we look at the schedule to determine what to produce next.
In a pull system, such as JIT, we look only at the next stage of production and determine what is needed there, and then we produce only that.
As Robert Hall states, “You don’t never make nothin’ and send it no place. Somebody has got to come and get it”.
Kanban Production ControlKanban Production Control
At the core of JIT manufacturing at Toyota is Kanban, an amazingly simple system of planning and controlling production.
Kanban, in Japanese, means card or marquee. Kanban is the means of signaling to the
upstream workstation that the downstream workstation is ready for the upstream workstation to produce another batch of parts.
Kanbans and Other SignalsKanbans and Other Signals
There are two types of Kanban cards: a conveyance card (C-Kanban) a production card (P-Kanban)
Signals come in many forms other than cards, including: an empty crate an empty designated location on the floor
Conveyance KanbanConveyance Kanban
Conveyance Kanban CardConveyance Kanban Card
Part number to produce: Part number to produce: M471-36M471-36 Part description: Part description: Valve HousingValve Housing
Lot size needed: Lot size needed: 4040 Container type: Container type: RED CrateRED Crate
Card number: Card number: 2 of 52 of 5 Retrieval storage location: Retrieval storage location: NW53DNW53D
From work center: From work center: 2222 To work center: To work center: 3535
Production KanbanProduction Kanban
Production Kanban CardProduction Kanban Card
Part number to produce: Part number to produce: M471-36M471-36 Part description: Part description: Valve HousingValve Housing
Lot size needed: Lot size needed: 4040 Container type: Container type: RED crateRED crate
Card number: Card number: 4 of 54 of 5 Completed storage location: Completed storage location: NW53DNW53D
From work center: From work center: 2222 To work center: To work center: 3535
Materials required:Materials required:Material no. Material no. 744B744B Storage location: Storage location: NW48CNW48CPart no. Part no. B238-5B238-5 Storage location: Storage location: NW47BNW47B
How Kanban OperatesHow Kanban Operates
When a worker at downstream Work Center #2 needs a
container of parts, she does the following: She takes the C-Kanban from the container she just
emptied. She finds a full container of the needed part in storage. She places the C-Kanban in the full container and removes
the P-Kanban from the full container and places it on a post at Work Center #1.
She takes the full container of parts with its C-Kanban back to Work Center #2.
Containers in a Kanban SystemContainers in a Kanban System Kanban is based on the simple idea of replacement of
containers of parts, one at a time. Containers are reserved for specific parts, are purposely kept
small, and always contain the same standard number of parts for each part number.
At Toyota the containers must not hold more than about 10% of a day’s requirements.
There is a minimum of two containers for each part number, one at the upstream “producing” work center and one at the downstream “using” work center.
Photo S12.4Photo S12.4
JIT exposes quality problems by reducing inventory
JIT limits number defects with small lots JIT requires TQM
Statistical process control Worker involvement
Inspect own work Quality circles
Immediate feedback
QualityQuality
Getting employees involved in product & process improvements Employees know job best!
JIT requires Empowerment Cross-training Training support Few job classifications
© 1995 Corel Corp.
Employee EmpowermentEmployee Empowerment
JIT in ServicesJIT in Services
All the techniques used in
manufacturing are used in services
SuppliersSuppliers
LayoutsLayouts
InventoryInventory
SchedulingScheduling
Benefits of JITBenefits of JIT
Inventory levels are drastically reduced: frees up working capital for other projects less space is needed customer responsiveness increases
Total product cycle time drops Product quality is improved Scrap and rework costs go down Forces managers to fix problems and eliminate
waste .... or it won’t work!