Lean Manufacturing Cellular Manufacturing One Piece Flow for Workteams Chapter 3 Basic Elements of Cell Design.

Lean Manufacturing

Cellular ManufacturingOne Piece Flow for Workteams

Chapter 3Basic Elements of Cell Design

Chapter 3 Overview

Phase 1 – Understanding the Current Conditions• Collect Product and Production Data• Document Current Layout and Flow• Time the Process• Calculate Process Capacity and Takt Time• Create Standard Work Combination Sheets

Phase 2 – Converting to a Process-Based Layout• Evaluate the Options• Plan Possible New Layouts• Move the Machines• Document the New Operating Procedures• Test to Confirm Improvement

Phase 3 – Continuously Improving the Process• Shorten Cycle Times• Shorten Changeover Times• Eliminate Product Defects• Reduce Equipment Failures

Summary

Converting Work Area into A Manufacturing Cell

Understanding the current conditions

Converting to a process-based layout

Continuously improving the process

Phase 1: Understanding the Current Conditions

Helps the conversion team determine what process to convert, and a base line to measure improvement.

Collect Product Data and Production Data• Product mix• Production resources (shifts, hours, employees, volume)

Document Current Layout and Flow• Process Route Analysis: helps to identify processing similarities

between different products and groups of products that could be made in a cell.

• Process Mapping• Time The Process: Determine the value-added ratio. The value-

added ratio is the time spent actually machining or working on the product divided by the total process lead time.

Calculate Process Capacity and Takt Time Create Standard Work Combination Sheet

Document the Current Process

Create Standard Work Combination Chart: Graphical display for each operation in the process. Depict the relationship between manual work time,

machine work time, and walking time for each step in an operation as well as the non-cyclical time.

Draw a solid line to indicate the Takt time.

Standard Work Combination Table - Definition

The Standard Work Combination Table combines human

movement and machine movement based on takt time and

is used as a tool to determine the range of work and work

sequence for which a team member is responsible.

Human work and Machine work

The key notion (idea) for the elimination of waste and the effective combination of work on the shop floor is the separation of machine work and human work.

When we observe the work in which operators handle machinery, then that work can be classified into machine or human work.

Understanding the separation of human and machine work is the basis for understanding the interface between these two elements.

If operators are merely observing the machine working then this is the waste of “Waiting” and should be eliminated.

Human work

This refers to work that cannot be completed without human effort. For example,

picking up materials

putting materials onto a machine

operating the controls of a machine

Machine work

This refers to work or incidental work that equipment, which has been started by human hand, automatically performs operations.

Milling

Auto riveting / bolting

Auto inspection

Standard Symbols

ManualAutomaticWalkingWaiting

The four basic symbols used in Standard work combination tables are:

Walk

Manual Work

Wait

TaktTime

HOW TO DISPLAY WORK ON THE STANDARDISED WORK COMBINATION TABLE

Automatic Cycle

HOW TO DISPLAY WORK ON THE STANDARDISED WORK COMBINATION TABLE

TT

1

2,4

3,5

Returning tothe same process.

Group Leader

STANDARDISED WORK COMBINATION TABLEPart Number / Name123ABC / Widget LH

Takt Time:162Qty / shift: 169

OPERATING TIME IN MINUTESTIMEWORKSEQ’ OPERATION

TOTALSOperatorWait time

MAN AUTO WALK

Manual

Process Machine and subassembly Cycle time

Available time:480’ Supervisor

Prod/Engineer

AutomaticWalkingWaitingDepartment: Machine

Issue date 30/09/99

1 Select part A

2 Set into M/C 1

3 Start machine

4 Select part B

5 Set into jig

6 Select part C

7 Fit C to B

8 Set C/B to m/c 2

9 Start m/c

10 Remove A from m/c 1

11 Set A to jig

12 Remove C/B from m/c

13 Screw C/B to A

14 Check torque

15 Put in finished bin

23

510

1520

2530

3540

4550

55 6570

7580

8560 90 100

95 105110

115120

125130

135140

145150

155160

10

1 842

93

23

153

11

1 412

37

35

315

82

22

2

5

5

TTCT

95125 34 33129

Phase 2: Converting to a Process-Based Layout

Evaluate the Options: how to improve the four basic element of production:• Methods• Machines• Materials• People

Plan Possible New Layouts• Layout in the process steps is the basic principle• Machines placed close together• U or C shape• Often Counterclockwise (R/H next to machine)

Move the Machines Document the New Operating Procedures Test to Confirm Improvement

Phase 3: Continuously Improving the Process

Rearranging the layout into a manufacturing cell is not really an end point - it is the beginning of continuous improvement

Look for problems that keeps the process from flowing:• Long cycle times• Product defects • Long changeover times• Equipment failures

Shorten Cycle Times

Phase 3: Continuously Improving the Process…

Shorten Changeover TimesSingle minute exchange of die (SMED) approach gives a three stage system

for shortening setup:

1. Separate Internal and External Setup (can reduce setup time by 30-50 %)• Internal setup refers to setup operations that can be done only with

the equipment stopped• External setup can be done while the machine is working

Typical activities include:• Transporting all necessary tools and parts to the machine while it is

still running the previous job• Confirming the function of exchangeable parts before stopping the

machine for changeover

2. Convert Internal Setup to External Setup• Standardized functions such as die height to eliminate the need for

adjustments.• Using devises that automatically position the parts without measurement

Phase 3: Continuously Improving the Process…

3. Streamline All Aspects of Setup• Using parallel operations, with two or more people working simultaneously • Using functional clamps instead of nuts and bolts• Using numerical setting to eliminate trial and error adjustments

• Eliminate Product Defects• Mistake proofing/Zero Quality Control (ZQC)- zero defects

Reduce Equipment Failure• Total Productive Maintenance (TPM): is a comprehensive, company-wide

approach for reducing equipment related losses such as downtime, speed reduction, and defects by stabilizing and improving equipment conditions.

Summary

Phase 1 – Understanding the Current Conditions• Collect Product and Production Data• Document Current Layout and Flow• Time the Process• Calculate Process Capacity and Takt Time• Create Standard Work Combination Sheets

Phase 2 – Converting to a Process-Based Layout• Evaluate the Options• Plan Possible New Layouts• Move the Machines• Document the New Operating Procedures• Test to Confirm Improvement

Phase 3 – Continuously Improving the Process• Shorten Cycle Times• Shorten Changeover Times• Eliminate Product Defects• Reduce Equipment Failures

Lean Manufacturing

Cellular ManufacturingOne Piece Flow for Workteams

Chapter 4Teamwork Tools for Cellular Manufacturing

Chapter 4 Overview

Working in Teams

Standardizing Workplace Conditions through 5S

Using Visual Management for Production Control

and Safety

Performing Autonomous Maintenance Activities

Using Activity Boards and One-Point Lessons

Summary

Working in Teams

Success depends on teamwork

In a cell, people work together in new ways

Several operations are combined in a sequence, and the main job of the people working in the cell is to maintain a smooth flow through the operations

Work must be coordinated

A group of employees has more creative potential and energy than any person working on a problem alone

Standardizing Workplace Conditions through 5S

Cellular manufacturing cannot succeed in a workplace that is cluttered, disorganized or dirty

Establishing basic workplace conditions is essential in creating a manufacturing cell

The 5S system is a set of five basic principles that have names beginning with S:• Sort• Set in Order• Shine• Standardize• Sustain

Using Visual Management for Production Control and Safety

Visual management is an important support for cellular manufacturing

Visual management techniques express information in a way that can be understood quickly by everyone

Sharing information through visual tools helps keep production running smoothly and safely

One form of visual management in manufacturing cells is the andon system:• Individual machines or assembly stations are equipped with call

lamps• If the machine breaks down or run out of parts, the operator or the

machine turns on a light to call attention

Using Visual Management for Production Control and Safety

Visual location indicators help keep order in the workplace• Lines, labels, and signboards

Visual information can also prevent to make mistakes• Color coding

• Matching color marks

Performing Autonomous Maintenance Activities

Activities carried out by shopfloor teams in cooperation with maintenance staff

Element of Total Productive Maintenance (TPM)

Changes old view that operators just run machines and maintenance people just fix them

Operators learn how to clean the equipment daily and how to inspect it for trouble signs as they clean

Learn the equipment and assist with repairs

Team-based activity: work with maintenance technicians and engineer

Using Activity Boards and One-point Lessons

Two useful approaches for making information public A bulletin board or wall chart

• Displays information about team activities and the results achieved• Chart improvement measures such as quality rate, On Time

Delivery, Overtime, Takt Rate, etc.• Helps keeping track of issues to follow up in the future

A one-point lesson • An easy to read poster to teach others about a particular problem• An improvement example, or • Basic knowledge that everyone should have• Kept short and focused on one point • Often illustrated with photos or drawings

Summary

Working in Teams

Standardizing Workplace Conditions through 5S

Using Visual Management for Production Control

and Safety

Performing Autonomous Maintenance Activities

Using Activity Boards and One-Point Lessons