4/17/2015 ieng 471 facilities planning 1 ieng 471 - lecture 05 group technology – production flow...

04/18/23 IENG 471 Facilities Planning 1

IENG 471 - Lecture 05

Group Technology –

Production Flow Analysis


Assignments

Current Assignment: HW 4Download spreadsheet from the Group Technology II Link on the

Materials page – follow the steps for Kings’ Algorithm HW: (HW 4) See Assignment Link

Individual AssignmentCan work together in groups, but each person turns in their own

assignmentPRINT out the initial and final matrix for each problemHighlight the family cells on the final matrixInterpret the final matrix of family cells – list which items

compose each family, AND discuss how that affects the operation of the facility

Next Assignment: Exam I


Volume, Variety & AutomationP

rod

uc

tio

n Q

ua

nti

ty

Part VarietyLow Medium High

High

Medium

Low

1 10 100 1,000

100,000

10,000

1,000

100

1

Mfg Cell

NC Machine

Flexible Mfg Sys

Transfer Line

Batch Flow Line

Increasing Productivity

Increasing Flexibility

Rembold, et. al.


Layout Impact on Facility’s Machines

Job Shop LayoutGroup by individual machinesAdd all equipment fractions, then round up*

Mass Production LayoutGroup by individual productsRound up* all equipment fractions, then add

Cellular LayoutGroup by similar part-process familiesAdd family equipment fractions, then round up*,

then add

* Multiply number of each machine type by footprint size after rounding to find the actual space required


Layout Patterns

Process Layout

Product Layout

Family / GT Cell Layout

Fixed Location Layout

Low Medium High

Product Variety

Low

Med

ium

Hig

h

Pro

duct

Vol

ume

Bulky, Difficult to Move Prod. (Planes, ships, etc.)

Bulky, Difficult to Move Equip.

(Precision fixtures)

Can Have Combinations (HYBRIDS)!


Examples

For the following situations, what type of General Layout would you suggest? The assembly of bodies for GM midsize SUVs

Fabrication & Assembly of custom made sheet metal parts

Fabrication of computer cases for a line of desktop PCs, plus custom made sheet metal parts

Assembly of three distinct families of electronic cards for inkjet printers

Production of high quality, custom office furniture


Group Technology (GT)

Philosophy:Use the similarity of current products to simplify

the design and manufacturing of new products Some Applications:

Identify and reuse similar process plansIdentify and reuse similar CNC programsIdentify the equipment that may be best used in a

particular machine cellIdentify and eliminate redundant inventory

Requirement:A taxonomy of part characteristics


Benefits of GT

Facilitates formation of part families and machine cells

Quick retrieval of designs, drawings, & process plans

Reduces design duplication

Provides reliable workpiece statistics

Facilitates accurate estimation of machine tool requirements and logical machine loadings

Permits rationalization of tooling setups, reduces setup time, and reduces production throughput time

Allows rationalization and improvement in tool design

Aids production planning and scheduling procedures

Improves cost estimation and facilitates cost accounting procedures

Provides for better machine tool utilization and better use of tools, fixtures, & people

Facilitates NC part programming.

(Ham)


How to Identify Groups

Similar Design AttributesSize of partsGeometric shape of partsMaterialsTechnique: Parts Classification & Coding

Similar Manufacturing AttributesCommon processing steps (routings)Common tools and fixturesTechnique: Production Flow Analysis

Similarity groupings are called Part Families


PFA Introduction PFA is Production Flow Analysis

A subset of Group Technology (GT)

Goals: Reduce material transport efforts Reduce set up efforts Reduce work in process inventory

Steps: Identify OP-Codes for each Component

Routing/Process Planning information for each part Incidence Matrix Blocking (Triangularization) Algorithm Cluster Identification


OP-Codes

An OP-Code forms an index to an Operation Plan

An Operation Plan is a generalized sequence of steps, perhaps common to multiple parts

An OP-Code Sequence is a method of condensing the Operation Plan into a compact structure suitable for data processing


OP-Code Example

OP Code Operation Plan01 Saw01 Cut to size02 Lathe02 Face end

Center drillDrillReamBoreTurn straightTurn grooveChamferCut offFaceChamfer

03 Grind01 Grind04 Insp06 Inspect dimension

Inspect finish

Rotational Part

(sectional view)


OP-Code ExampleOP Code Operation Plan01 Saw01 Cut to size02 Lathe02 Face end

Center drillDrillReamBoreTurn straightTurn grooveChamferCut offFaceChamfer

03 Grind01 Grind04 Insp06 Inspect dimension

Inspect finish

OP Code Sequence01 Saw01

02 Lathe02

03 Grind01

04 Insp06


Incidence Matrix

Rows represent OP-Codes (index = i) Columns represent Components (index = j) Cell Entries are: (Mij)

1 (or mark) - if the component requires the operation 0 (or blank) - if the component does NOT require the operation

A-112 A-115

Saw01 1

Lathe01

Lathe02 1

Drill01 1

Mill02 1

Mill05

Grind05 1


King’s Algorithm – Step 1 Calculate the total (binary) weight of each column j:

Wj = 2i Mij

i

A1 A2 A3 A4 A5 A6 A7 A8 A9 A0 2i i

S01 1 1 1 1 1 1 2 1

L01 1 4 2

L02 1 1 1 1 1 8 3

D01 1 1 16 4

M02 1 32 5

M05 1 1 1 64 6

G05 1 128 7

G06 1 256 8

Wj

138 48 10 6 10 64 64 10 10

336

Rank 5 3 2 1 2 4 4 2 2 6

After Chang, Wysk, & Wang (1998) p.500


King’s Algorithm – Step 2

Sort the columns into rank order, then go to Step 3:

A4 A3 A5 A8 A9 A2 A6 A7 A1 A0

S01 1 1 1 1 1 1

L01 1

L02 1 1 1 1 1

D01 1 1

M02 1

M05 1 1 1

G05 1

G06 1

Wj 6 10 10 10 10 48 64 64

138

336

Rank 1 2 2 2 2 3 4 4 5 6



A4 A3 A5 A8 A9 A2 A6 A7 A1 A0 Wi Rank

S01 1 1 1 1 1 1 574 4

L01 1 2 1

L02 1 1 1 1 1 602 5

D01 1 1 1088 7

M02 1 64 2

M05 1 1 1 1408 8

G05 1 512 3

G06 1 1024 6

2j

2 4 8 16 32 64

128

256

512

1024

j 1 2 3 4 5 6 7 8 9 10

Calculate the total (binary) weight of each row i:

Wi = 2j Mij

j




L01 1 2 1

M02 1 64 2

G05 1 512 3

S01 1 1 1 1 1 1 574 4

L02 1 1 1 1 1 602 5

G06 1 1024 6

D01 1 1 1088 7

M05 1 1 1 1408 8

If all rows are in rank order STOP; otherwise, sort the rows into rank order, and then go to Step 1:


King’s Algorithm – Step 1 (2nd time)

A4 A3 A5 A8 A9 A2 A6 A7 A1 A0 2i i

L01 1 2 1

M02 1 4 2

G05 1 8 3

S01 1 1 1 1 1 1 16 4

L02 1 1 1 1 1 32 5

G06 1 64 6

D01 1 1 128 7

M05 1 1 1 256 8

Wj 18 48 48 48 48

132

256

256 56

448

Rank 1 2 2 2 2 4 5 5 3 6

Calculate the total (binary) weight of each column j:

Wj = 2i Mij

i



A4 A3 A5 A8 A9 A1 A2 A6 A7 A0

L01 1

M02 1

G05 1

S01 1 1 1 1 1 1

L02 1 1 1 1 1

G06 1

D01 1 1

M05 1 1 1

Wj 18 48 48 48 48 56

132

256

256

448

Rank 1 2 2 2 2 3 4 5 5 6





L01 1 2 1

M02 1 128 5

G05 1 64 2

S01 1 1 1 1 1 1 126 4

L02 1 1 1 1 1 124 3

G06 1 1024 6

D01 1 1 1152 7

M05 1 1 1 1792 8

2j

2 4 8 16 32 64

128

256

512

1024

j 1 2 3 4 5 6 7 8 9 10


Wi = 2j Mij

j




L01 1 2 1

G05 1 64 2

L02 1 1 1 1 1 124 3

S01 1 1 1 1 1 1 126 4

M02 1 128 5

G06 1 1024 6

D01 1 1 1152 7

M05 1 1 1 1792 8

If all rows are in rank order STOP; otherwise, sort the rows into rank order, and then go to Step 1:


King’s Algorithm – Step 1 (3rd time)

A4 A3 A5 A8 A9 A1 A2 A6 A7 A0 2i i

L01 1 2 1

G05 1 4 2

L02 1 1 1 1 1 8 3

S01 1 1 1 1 1 1 16 4

M02 1 32 5

G06 1 64 6

D01 1 1 128 7

M05 1 1 1 256 8

Wj 18 24 24 24 24 26

160

256

256

510

Rank 1 2 2 2 2 3 4 5 5 6

Calculate the total (binary) weight of each column j:

Wj = 2i Mij

i



A4 A3 A5 A8 A9 A1 A2 A6 A7 A0

L01 1

G05 1

L02 1 1 1 1 1

S01 1 1 1 1 1 1

M02 1

G06 1

D01 1 1

M05 1 1 1

Wj 18 24 24 24 24 26

160

256

256

510

Rank 1 2 2 2 2 3 4 5 5 6


NO CHANGE IN SORTED ORDER!




L01 1 2 1

G05 1 64 2

L02 1 1 1 1 1 124 3

S01 1 1 1 1 1 1 126 4

M02 1 128 5

G06 1 1024 6

D01 1 1 1152 7

M05 1 1 1 1792 8

2j

2 4 8 16 32 64

128

256

512

1024

j 1 2 3 4 5 6 7 8 9 10


Wi = 2j Mij

j




L01 1 2 1

G05 1 64 2

L02 1 1 1 1 1 124 3

S01 1 1 1 1 1 1 126 4

M02 1 128 5

G06 1 1024 6

D01 1 1 1152 7

M05 1 1 1 1792 8

If all rows are in rank order STOP; otherwise, sort the rows into rank order, and then go to Step 1:SINCE THE ROWS WERE IN RANK ORDER, WE STOP! (yea!)


Partitioning

A4 A3 A5 A8 A9 A1 A2 A6 A7 A0

L01 1

G05 1

L02 1 1 1 1 1

S01 1 1 1 1 1 1

M02 1

G06 1

D01 1 1

M05 1 1 1

Ideally, the cells form mutually exclusive blocks (as below). These blocks define the Families: Family A consists of Components A1, A3, A4, A5, A8, and A9; which

can be machined in a cell performing Operations G05, L01, L02, and S01

Family B consists of Components A0, A2, A6, and A7; which can be machined in a cell performing Operations D01, G06, M02, and M05


Partitioning

A4 A3 A5 A8 A9 A1 A2 A6 A7 A0

L01 1

G05 1

L02 1 1 1 1 1

S01 1 1 1 1 1 1

M02 1

G06 1 1

D01 1 1

M05 1 1 1

Often, the cells do NOT form mutually exclusive blocks (as below). In this case, the capability for Operation G06 must be common to both machining cells: Family A consists of Components A1, A3, A4, A5, A8, and A9; which can be

machined in a cell performing Operations G05, G06, L01, L02, and S01 Family B consists of Components A0, A2, A6, and A7; which can be

machined in a cell performing Operations D01, G06, M02, and M05


Strategies for Overlapping PFA Blocks:

Provide for transporting some components between cells requiring the overlapping operation(s)

Pick the component(s) with the smallest volume(s) to transport to reduce handling costs

Locate the cells with operation overlap as near to each other as possible to reduce handling costs

Avoid scheduling concurrent production runs of the components that require overlapping operation(s)

Assumes that the equipment providing the overlapping capability can be easily moved between cells

This solution may improve capacity if the overlapping operation is a bottleneck

Put equipment capable of the overlapping operation(s) into each cell requiring it

Assumes the additional equipment capability is cost justifiableThis solution will improve capacity if the overlapping operation is a

bottleneck


Extended GT (PFA) Requirements:

Need for grouping similar items together, and identifying separable items

Matrix of related entities:ToolingEquipmentPartsIntegrated CircuitsModular Components

Solution Method: TriangularizationDirect Clustering AlgorithmKing’s MethodKusiak’s Triangularization MethodUllman’s Design Structure Matrix


Relationship (Incidence) Matrix

Rows and Columns:Parts requiring operations on different machinesTools (in a CNC magazine) needed to produce

part familiesDepartments requiring technicians (shared head

count)Departments requiring adjacent locationICs requiring modularization

An entry in the incidence matrix means that there is a strong relationship between the row and column items

4/17/2015 ieng 471 facilities planning 1 ieng 471 - lecture 05 group technology – production flow...

Documents

cellular layout group

layout impact

mass production layout

type of general layout

machine type

family equipment fractions

process families

custom office furniture