The Lean Enterprise JIT / Cellular Concepts

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Lean Foundations

Continuous Improvement Training

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Learning Objectives

• Learn philosophy of ‘Cellular’ production and understand 3 basic components of Just-In-Time (JIT)

• List 7 production characteristics of a JIT oriented Cell layout

• Review the steps to identify and remove waste and design a sample work cell to meet takt time

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Costs will eventually drop by relentlessly addressing these,

in succession

The Philosophy of ‘Just-in-Time’ (JIT)

Manufacture most economically:

• Only what is needed/ sold now

• Only in the amount needed now

• Only when it is needed

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Identified by:

1. Continuous process flow

2. Production according to TAKT time

3. Pulling subsequent processes

(Refer to module on “Kanban”)

3 Components of

Just-in-Time Production

One piece/ one ‘set’ flow with no WIP between processes

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Cellular Production Characteristics

Machines in order of process

Small and inexpensive equipment

One piece flow production

Multi process handling workers

Easy moving/ standing operations

U-cell layout (Counterclockwise)

Production paced (JIT) to TAKT time

Sample

‘U-shaped’

Cell

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Production paced to TAKT time

- Output requirements determine TAKT time

- Most important measurement in manufacturing

- Operations must be constructed around TAKT time

“TAKT” Time Is The Beat Of Production

TAKT time example:

Available hrs* = 7 hrs.

Daily quantity required = 40

TAKT Time = 7 hrs X 60 min/hr = 10.5 min/pc

40 pcs

1 unit must ship every 10.5 minutes

Need to perform each operation only once every 10.5 minutes

* 8 hours minus ½ hour lunch

and two 15-minute breaks

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1. Net operating time - Normal day

- One shift @ 8 hours = 480 min

- Breaks: 2 @ 15 min = 30 min

- Available working time = 450 min

2. Customer requirements

The number of completed transactions per time period

- Orders per month = 360 - Working days per month = 20 - Average customer orders/day = 18

TAKT Time = 450 min = 25 min per order 18 Orders

Business Process TAKT Time - example

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It is composed of five elements:

1. Work sequence

2. Equipment used

3. Operation description

4. TAKT time

5. Workers required

The combination of people, materials, machines, and

methods required to produce in such a way as to

minimize waste

Standardized Operations = Best Methods

Need to know the time it takes to process the task

Sample

Cell layout

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1 2 3

4 5 6

1

3 4

1

2

Work Sequence

Raw

Material

In 2

Finished

Goods

Out

… the order in which an operator performs a series of

repetitive tasks (light blue lines below).

It should be differentiated from the processing

sequence which is the order the part or “unit” is

processed.

1

A B

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How to Remove Waste Walk the process

Process Map (refer to Mapping modules)

Collect process data

Label as value-added or non-value added

Calculate TAKT time

Graph Operational times classified as

value-added and non-value added

8 hr

Non-

value

added

Activity Bar Chart

Value

added

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How to Remove Waste

Remove or reduce non-value added steps

Challenge whether value-added steps are really

value-added (refer to Mapping Analysis modules)

Develop new layout or process

Level the load and determine the work sequence

8 hr Non -

value

added

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Proposed layout

How many people?

What would they do?

010 (Operation)

Raw

Material

In

Finished

Goods

Out

Work Center M101 020

M103

030 D201

040

D300

090

B405

080

I101

070

B205

060

B100

050

W94

A New Layout (Cell) To Reduce Waste

turning boring drilling

spot facing

cleaning de-burring

assembly inspection

packing

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TURN BORE DRILL SP'FACE CLEAN DEBURR ASSY. INSPECT PACK

0

5

10

15

20

25

30

35

40

TAKT

3 3

7

12

5 6

12

6 4

TAKT time / Cycle time

Process Time For Operations (example)

TAKT time =

(150 pc / wk) / (5 days / wk)

(2 shift/day) (7.5 hours/shift)

= 30 minutes

*Assume these are the value-added operations

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Balance the Load and Keep Waste Low

TURN BORE DRILL SP'FACE CLEAN DEBURR ASSY. INSPECT PACK

0

5

10

15

20

25

30

35

40

TAKT

3 3

7

12

5 6

12

6 4

TAKT time / Cycle time

Total Manpower = Tot. Cycle Time* 58

TAKT Time 30 = = 2

But -

keep person working in a close area to avoid waste

try to have person who “starts” the job, “finish” the job to

help facilitate working only on what is needed

have person “work with the flow” as much as possible

Combine operations for each operator

which will meet TAKT time

An iterative process with some solutions better than others

*Note: “cycle time” refers to “touch time” not “lead time” or voucher time

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D201

Proposed staffing plan

1 2

3 4 5

1 2

3 4

010

M101 020

M103

040

D300

090

B405 080

I101

070

B205

060

B100

050

W94

Raw

Material

In

Finished

Goods

Out

New Layout And Better Alignment of Work

Assignments (light blue lines)

60

50

40

30

90

80

70

Person A B

30

If TAKT time cannot be met for a given operation --

work to remove WASTE

TAKT time can be met

20 10

030

Kanban

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JIT/ Cell Concepts – Best Practices

• Balance the Work Load Among Associates

• Reduce the Walking Distances

(refer to Value Stream Mapping)

• Keep Only the Necessary Quantities of In-Process

Stock at the Work Station (refer to Kanban/ Flow)

• Automate Machine Feed and Ejection (refer to TPM)

• Change the Height, Angle or Location of the Part

Racks (refer to Kaizen)

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JIT/ Cell Concepts – Best Practices

• Change the Work Sequence (refer to Kanban/ Flow)

• Use “Two-Handed” Work Where Possible

(refer to Standardized Operations/ Standard Work)

• Reduce the Manual Adjustments Necessary to Make

Different Parts (refer to Set-up reduction)

• Use Specialized Tools (refer to Visual Management)

• Find Countermeasures to Prevent Defects

(refer to Mistake-proofing / Poka-Yoke)

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• The Just-In-Time (JIT) concept is used within Lean

Manufacturing. The idea in this philosophy is to

manufacture most economically:

- only what is needed/ sold now,

- only in the amount needed now,

- and only when it is needed

• Each operation should ‘produce’ to TAKT time.

TAKT time is determined by:

Amount of available production time

Demand

Summary

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Summary

• A value-added activity is an activity that transforms or shapes raw material or information to meet customer requirements

• A non-value-added activity (or waste) takes time, resources or space, but does not add to the value of the product or service itself

• Waste can take many forms; some of the most common are: unnecessary approvals or signatures, reviews of reviews, multiple hand-offs, transportation, correction, over-production, mass inspection

• In most cases, inventory is wasteful; more importantly, inventory hides all sorts of problems in the company

• Mapping the process and evaluating different work flow layouts is one of the keys to reducing waste

The Lean Enterprise JIT / Cellular Concepts

www.freeleansite.com

Lean Foundations

Continuous Improvement Training