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mechanical engineering(manufacturing)
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Computer Integrated Manufacturing (CIM)
MEM562 :JIT & Kanban System
WEEK 14:
Just-In-Time Production
Kanban System
Autonomation
Human Factors
UNIVERSITI TEKNOLOGI MARA
FACULTY OF MECHANICAL ENGINEERING
1 RJ, CIM 2012
Just-In-Time Production Production and delivery of exactly the required number of
each component to the downstream operation in the
manufacturing sequence just at the moment when the
component is needed.
JIT concept has the following goals:
Receive supplies JIT to be used.
Produce parts JIT to be made into subassemblies.
Produce subassemblies JIT to be assembled into
finished products.
Produce and deliver finished products JIT to be sold.
Etc.
2 RJ, CIM 2012
Benefits
Unnecessary inventories
Unnecessary warehouse and stores
Inventory carrying costs diminished
3 RJ, CIM 2012
Requisites for JIT
1. A pull system of production control.
2. Setup time reduction for smaller batch sizes
3. Stable and reliable production operations
Minimizes:
Work-in-process
Manufacturing lead time
4 RJ, CIM 2012
Kanban System
Kanban means card in Japanese. This is a tool to
achieve JIT.
Two types of kanbans:
1. Production kanban authorizes upstream station to
produce a batch of parts. It specifies the kind &
quantity of product which the preceding process must
produce.
2. Transport (withdrawal) kanban authorizes transport
of the parts to the downstream station. Specifies the
kind and quantity of product which the subsequent
process should withdraw from the preceding process.
5 RJ, CIM 2012
Kanban System
When the producer and user are not in visual
contact, a card can be used.
When the producer and user are in visual contact,
a flag or empty spot on the floor may be
adequate.
Each card controls a specific quantity or parts.
Provides a direct control and limit on the amount
of WIP between cells.
Two-card system between producer and user.
6 RJ, CIM 2012
To realize the JIT purpose of Kanban
Rule 1: The subsequent process should withdraw
the necessary products from the preceding
process in the necessary quantities at the
necessary point in time.
Rule 2: The preceding process should produce its
products in the quantities withdrawn by the
subsequent process.
Rule 3: Defective products should never be
conveyed to the subsequent process.
7 RJ, CIM 2012
Continue
Rule 4: The number of Kanbans should be
minimized.
Rule 5: Kanban should be used to adapt to
small fluctuations in demand
Advantages of Kanban???
8 RJ, CIM 2012
Autonomation (Jidoka) Not automation, but autonomous check of abnormality in
process - Automation with a human touch.
When equipment & operators function under normal
conditions, the approach should be zero quality-problem
operation.
Production machines operate autonomously as long as they are
functioning properly. When they do not function properly (e.g.,
they produce a defect), they are designed to stop.
Autonomous machine is attached to an automatic stopping
device, so mass production of defects can be prevented and
machine breakdowns are automatically checked.
Build quality into the process, separate man and machine using
intelligent automation.
9 RJ, CIM 2012
Autonomation
Eg. If something abnormal happens in a
production line, the worker pushes the stop button
and stopping the whole line. For detecting
troubles, an electric light board (Andon) indicates
a line stop which is hung high in a factory can be
seen by everyone.
Objectives: (1) 100% quality (good units) at all
times, (2) prevention of equipment breakdowns &
(3) efficient use of every worker.
10 RJ, CIM 2012
Pull / Pull System of Production
Control
A pull system in which the order to make and deliver parts
at each workstation in the production sequence comes from
the downstream station that uses those parts.
In this system, information flows in the opposite direction
as production.
Alternative is a push system in which parts are produced at
each station irrespective of the immediate need for those
parts at the downstream station.
The information flows in the same direction as production.
Information flows is the main difference.
11 RJ, CIM 2012
Push Manufacturing
Push manufacturing is characterized by
manufacturing to forecast, emphasizes on
batch processing and lot sizes.
Each area runs at maximum capacity and
the material is pushed downstream.
MRP
12 RJ, CIM 2012
Pull Manufacturing
Pull manufacturing is a visual
replenishment of goods, produced when
demanded by the next work center.
Kanban???
JIT
Benefits & drawbacks???
13 RJ, CIM 2012
14 RJ, CIM 2012
Human Resources Issues in
Manufacturing
Management of the manufacturing workforce in a
highly automated facility is changing as a result
of internal & external factors.
Two key internal issues: (1) the interaction of the
operator with the machine changed significantly
when manual machines were replaced with
computer-controlled processes, & (2) the highly
integrated nature of the automated production
systems and the enterprise requires a new set of
skills.
15 RJ, CIM 2012
Human Resources Issues in
Manufacturing
External factors are linked to changes in
workforce management: expanding global
marketplace (the ability to survive) and the
evolution of the workforce (to develop a
mechanism to meet market demands result
from worldwide competition).
16 RJ, CIM 2012
Self-Directed Work Teams
Moving towards delegation. Granting of
permission to carry out a task.
Establishment of quality circle groups to
perform group problem analysis.
The empowerment started with quality
circle groups gives greater authority to
work on their own and the initiation of
cross-functional corrective, action teams.
17 RJ, CIM 2012
The Social Impact
The impact will be the unskilled workers
will not be needed to run the production
machines & perform manual labor tasks.
A shift from direct labor jobs to indirect
labor jobs. Indirect labor will include
highly trained technicians positions in
maintenance, computer programming, etc.
Retraining & education.
18 RJ, CIM 2012
2. Setup Time Reduction
Starting point in setup time reduction is
recognition that the work elements in
setup are of two types:
1. Internal elements can only be done while
the production machine is stopped.
2. External elements do not require the
machine to be stopped.
19 RJ, CIM 2012
External Work Elements
Can be accomplished while previous job is still running.
Strategy:
Design the setup tooling and plan the changeover
procedure to permit as much of the setup as possible
to consist of external elements.
Examples:
Retrieve tooling for next job from tool crib.
Assemble tools for next job.
Reprogram machine for next job.
20 RJ, CIM 2012
Internal Work Elements Use time & motion study and methods improvement to
minimize the sum of the internal work element times.
Use two workers rather than one to accomplish the
changeover.
Eliminate adjustments in the setup.
Use quick-acting fasteners rather than bolts and nuts.
Use U-shaped washers instead of O-shaped washers.
Design modular fixtures consisting of a base plus insert
tooling that can be quickly changed for each new part
style.
Base part remains attached to production machine.
21 RJ, CIM 2012
3. Stable & Reliable Production Operations
Production leveling - distribute changes in
product mix and quantity as evenly as possible
over time.
On-time delivery of components.
Defect-free components and materials.
Reliable production equipment.
Workforce that is cooperative, committed, and
cross-trained.
Dependable supplier base.
22 RJ, CIM 2012
(3) Worker Involvement
Factories include people. To function well,
people and technology must integrate in a
system exploiting the strengths and
minimizing the limitations of each
component.
Participation of all employees. Teams are
integrated with work cells for motivation,
work management & problem solving.
23 RJ, CIM 2012
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