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Production Flow Analysis

Group 9

Kumara Swamy - 41Neha - 42Lokhinath - 43Mamta Sahare - 44Mangal Deep - 45

What is Group Technology (GT)?

• GT is a theory of management based on the principle that similar things should be done similarly

• GT is the realization that many problems are similar, and that by grouping similar problems, a single solution can be found to a set of problems thus saving time and effort

• GT is a manufacturing philosophy in which similar parts are identified and grouped together to take advantage of their similarities in design and production

Implementing GT

Where to implement GT?• Plants using traditional batch production and process � �

type layout• If the parts can be grouped into part families�How to implement GT?�• Identify part families�• Rearrange production machines into machine cells�

Types of Layout

In most of today’s factories it is possible to divide all the made components into families and all the machines into groups, in such a way that all the parts in each family can be completely processed in one group only

The three main types of layout are: • Line (product) Layout• Functional Layout• Group Layout

Large manufacturing system can be decomposed into smaller subsystems of part families based on similarities in

1. design attributes and

2. manufacturing features

Identifying Part Families

Design Attributes:• part configuration (round or prismatic)• dimensional envelope (length to diameter ratio)• surface integrity (surface roughness, dimensional

tolerances) • material type• raw material state (casting, forging, bar stock, etc.)


Part Manufacturing Features:• operations and operation sequences (turning, milling, etc.)• batch sizes• machine tools• cutting tools• work holding devices• processing times


Group technology emphasis on part families based on similarities in design attributes and manufacturing, therefore GT contributes to the integration of CAD and CAM.


Forming Part Families –Classification and Coding: Production Flow Analysis (PFA)

• PFA is a method for identifying part families and associated machine groupings based on the required manufacturing processes need for each part.

Production flow analysis involves four stages:

Stage 1: Machine classification.

Machines are classified on the basis of operations that can be performed on them. A machine type number is assigned to machines capable of performing similar operations.

Machine - Component Group Analysis

Stage 2: Checking parts list and production route information.

For each part, information on the operations to be undertaken and the machines required to perform each of these operations is checked thoroughly.


Stage 3: Factory flow analysis.

This involves a micro-level examination of flow of components through machines. This, in turn, allows the problem to be decomposed into a number of machine-component groups.


Stage 4: Machine-component group analysis.

An intuitive manual method is suggested to manipulate the matrix to form cells. However, as the problem size becomes large, the manual approach does not work. Therefore, there is a need to develop analytical approaches to handle large problems systematically.


Identifying Manufacturing Cells Using Production Flow Analysis

Production Flow Analysis

• A technique for forming part families based on Operation Routing Summaries

• Several methods available. We will discuss 2 algorithms for PFF (Part Family Formation)

Let’s consider 5 parts (n) and 6 machines (m):

n = {101, 102, 103, 104, 105}

m = {Drill1, Drill2, Mill1, Mill2, Vbore1, Vbore2} = {D1, D2, M1, M2, V1, V2}

Part No. Routing Times (min) Ave. Dem.101 D1 -M1 - V1 9 - 12 - 14 100102 D2 -M2- V1 5 - 11 - 14 250103 D1 -M1 7 - 9 700104 M2 - V2 - D2 8 - 12 - 5 100105 V1 - M1 - D1 7 - 10 - 12 200

King’s Algorithm (Rank Order Clustering) Step#1Calculate the total column width for each column

Part# (j) 101 102 103 104 105

D1 1 0 1 0 1 2D2 0 1 0 1 0 4M1 1 0 1 0 1 8M2 0 1 0 1 0 16V1 1 1 0 0 1 32V2 0 0 0 1 0 64

42 52 10 84 42

1

Machine# (i)

23456

2i

Generate 2i

å"

=i

ij mw i2

Sum: mi,j * 2i

for each column (wj)Done!

(wj)

#2. If Wj is in ascending order, go to step #3; otherwise, rearrange the columns to make Wj fall in an ascending order.

103 101 105 102 104 å i

D1 1 1 1 0 0 14D2 0 0 0 1 1 48M1 1 1 1 0 0 14M2 0 0 0 1 1 48V 1 0 1 1 1 1 28V 2 0 0 0 0 0 32

10 42 42 52 84wj

101 105

104

102

103

#3. "i, calculate the total row weight, wi`

å"

=j

ijj

i m2w

103 101 105 102 104

D1 1 1 1 0 0 14D2 0 0 0 1 1 48M1 1 1 1 0 0 14M2 0 0 0 1 1 48V1 0 1 1 1 1 28V2 0 0 0 0 0 32

2 4 8 16 322j

wi

Sum: mi,j * 2j

for each row (wi)

Generate 2j

Done!

Discussion

• Good rectangles mean that you have very distinctive part families

• Do Parts no 103, 101, 105 have a distinct code so that a can be made to distinguish them from #102, 104.

• Cell formation• Volume / Floor space• Size of problems • How about King’s algorithm? Will it always work?• Are there problems with it?

F

DIRECT CLUSTER ALGORITHM

101 102 103 104 105D1 1 0 1 0 1D2 0 1 0 1 0M1 1 0 1 0 1M2 0 0 0 1 0V1 1 1 1 0 1V2 0 0 0 1 0

wi

323141

Step #1. For I, calculate the total no. of positive cells in row, i

j

ijMiw

all

101 102 103 104 105V1 1 1 1 0 1D1 1 0 1 0 1M1 1 0 1 0 1D2 0 1 0 1 0M2 0 0 0 1 0V2 0 0 0 1 0

wi

433211

3 2 3 3 3 1

Sort rows in descending order of the wi values

D1

M2

V1D2

No Change

No Change

Done!

Step #3. For i = 1 to n, move all columns j where mij = 1 to the left maintaining the order of previous rows.

101 103 105104102V1 1 1 101D1 1 1 100M1 1 1 100D2 0 0 011M2 0 0 010V2 0 0 010

Move Column 105 to the left and push column 104 back

Observe Elements of Row 1

Step #4. For j = m to 1, move all rows I, where mij = 1 to the top maintaining the order of the previous columns, wij

101 103 105104 102V1 1 1 10 1D1 1 1 10 0M1 1 1 10 0D2 0 0 01 1M2 0 0 01 0V2 0 0 01 0

Observe Elements of Column 102

Observe Elements of Columns 101, 103 & 105: No Change can be made!!

Move Row D2 upwards and push row D1 down

101 103 105104 102

V1 1 1 10 1

D1 1 1 10 0M1 1 1 10 0

D2 0 0 01 1M2 0 0 01 0V2 0 0 01 0

Identify Cells or potential Cells

Cell #1

Cell #2

Part Family #1 Part Family #2

Different type analysis

Company Flow Analysis

• division of large companies into factory components• aims to simplify the flow of materials between factories• Uses FROM-TO charts and frequency charts and a flow

analysis• Presentation of data for company goal

• Study and map the existing flow system• Identify the dominant material flows between shops (or

buildings)• Determine the Process Route Number (PRN) for each

part• Analyze the part by PRN.• Combine closely associated processes at departments

that complete most of the parts they make• If parts are observed to backtrack then such flows are

eliminated by minor redeployment of equipment

Factory Flow AnalysisAn attempt is made at this stage to find major groups of

departments, and major families of components which can be completely processed in these departments

Group Analysis

• The flows in each of individual shops are analyzed. • Operation sequences of the parts that are being

produced in a particular shop are analyzed to identify manufacturing cells.

• Loads are calculated for each part family to obtain the equipment requirements for each cell

Line Analysis

A linear or U-layout is designed for the machines assigned to each cell.

The routings for each part assigned to the cell and the frequency of use of each routing are used to develop a cell for: – Efficient transport, &– Minimum material handling

Tooling Analysis

• A Tooling Analysis helps to schedule the cell by identifying families of parts with similar operation sequences, tooling and setups.

• It seeks to sequence parts on each machine to sequence all the machines in the cell to reduce setup times and batch sizes.

• This increases available machine capacity on bottleneck work canters in the cell.

Case on Manufacturing Cell Formation Using Production Flow

Analysis

Overview

• The cell redesign in this work is tightly focused to reach optimization of material flows under real manufacturing conditions

• Aim to built one-piece flow production

• Case study was concentrated on relatively typical situation of transformation from batch production to cellular manufacturing

Introduction

• The following research deals with theoretical background for application of one-piece concept by applying the principles of Product/Quantity (P-Q) analysis and production flow analysis (PFA)

• The factory push their outputs to retailers, retailers are returning what they cannot sell and returned products ends up as a dead inventory

• By contrast this system outputs products based on the needs of the assembly processes, which are the closest processes to the market and therefore customer

Research Background • The sense of material flow optimisation is to help

planners to satisfy customer’s needs in shortened manufacturing time cycles

• Material flows can be implemented as:1. Discrete flows, which are typical mainly for a batch

production. This category involves the manufacture of medium-sized lots of the same item or product. The lots may be produced only once, or they may be produced at regular intervals

2. Continuous material flows are ordinarily applied in chemical and food industry. While these are examples of flow production, the term also applies to the manufacture of either complex single parts or assembled products

Research Background

• The role of the cell formation is transformation of discrete material flows to almost continuous material flows with the aim to change planning - centred production on one-piece production

• Reduction in inventory is realized due to:1) Parts are not being stored in containers (unit loads) at

operations while they are being processed. Instead onepiece at a time is processed in cells and ideally only onepiece is in transit between operations

2) Parts are made as they are ordered. Batches or lots ofparts are not staged between operations waiting to bescheduled and then to be processed

Research Background

The basic conditions for establishing one-piece flow systems are:

• Make the factory layout conductive to the overall production flow

• The factory must include clear pathways• The production line should clearly distinguish between

material input and product output• The production line should consist mainly of single operator U-

shaped cells• Include thorough inspection in the layout• Minimize in-process inventory

POBLEM AND METHOD DESCRIPTION

• The company produces bicycle components, which differ in shapes and sizes

• Lots are produced more or less at regular intervals• The manufacturing equipment was conventionally designed

for higher rates of production• The machine tools are combined with specially designed

jigs and fixtures, which increase the output rate• Flexibility of production is ensured by semi-automatic

machines• An effective design should take into account an

organization’s products, facilities, and procedures for planning and controlling operations, minimum ergonomic requirements for equipment, and short and long-term goals

Production equipment layout and material flow before cell formation

Semi product No

Quantity (pcs/yr)

Cumul. Qty (pcs/yr)

Cumul. Share (%)

1 405870 405870 242 270580 676450 403 266966 943416 564 256311 1199727 715 101700 1301427 776 88990 1390417 827 76276 1466693 878 69404 1536097 919 53704 1589801 94

10 39176 1628977 9611 34702 1663679 9812 29382 1693061 100

INITIAL PRODUCTION DATA

Actual P-Q diagram (P- product type, Q-quantity)

X1- amount of manufactured products related to 20% of produced assortmentX2- amount of manufactured products related to 30% of produced assortmentX3- amount of manufactured products related to 40% of produced assortmenta) if X1 approaches 80%, then building a wide-variety small lot production line is reasonable i.e. apply one-piece flow conceptionb) if X2 lays around 70% value, decision about production equipment layout depends more or less on intuition and experience of a manager, even though fuzzy criteria for such decision makingc) if X3 approaches 60%, it is reasonable to organize production equipment in technological pattern due to relations between assortment and amount of manufactured pieces being not suitable for implementing one-piece flow principles

Interval of the interest

R1: If value X2 is greater than or equal 70%, then it is strongly recommended to establish wide-variety small-lot production layout in factory thus implementing one-piece flow conception

R2: If value X2 is smaller than 70% and X2 is greater than 65 % or X3 is greater then X2, then it is more or less appropriate to built up wide-variety small-lot production system

R3: If value X2 is smaller then 70% but X2 is greater then X3 then conditions for implementing one-piece flow are not satisfied so the production equipment layout should be organized in technological pattern

Decision-making algorithm

Multi-product process chart

• Based on multi-product process chart further steps of Production flow analysis can be applied. Each stage in PFA seeks to eliminate delays in production flows and operational wastes in a progressively smaller area of the factory

• PFA can be defined as comprehensive method for material flow analysis, part family formation, design of manufacturing cells, and facility layout design

• In real conditions, the cells are often organized into a U-shaped layout, which is considered appropriate when there is a variation in the workflow among the parts made in the cell.It also allows the multifunctional workers in the cell to move easily in between machines

Product layout disposition after transformation

A new 6-line production equipment layout

CONCLUSION

• Transformation of production process can be viewed as perspective way of optimization of material flows by changing production equipment layout and achieving the goals of company

• Material flow optimization belongs among complex engineering and managerial problems

• Conducting this study from one side helped to verify the effectiveness of decision-making based on criteria of P-Q analysis

• On the other hand, transforming of current production equipment layout to 6 lines led to improvement of more important economical aspects in a company

REFERENCES

• D.M. Lambert, M.C. Cooper, and J. D. Pagh, “Supply Chain Management: Implementation Issues and Research Opportunities”

• M. P. Groover, Automation, production systems, and computer integrated manufacturing

• International Journal of Aerospace and Mechanical Engineering 3:4 2009: Case on manufacturing cell formation using PFA by Vladimir Modrak

Documents

ProduProduction flow analysisction Flow Analysis