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products in the quantities withdrawn by the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