3Rawabdeh Lecture 3 2011

7/30/2019 3Rawabdeh Lecture 3 2011

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Dr. Ibrahim Rawabdeh (2010-2011)

Relationship between product, process, and schedule design and

facilities planning

Production

planner

Product designers Process planner

Facilities

planner


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3Dr. Ibrahim Rawabdeh (2010-2011)

Before any faci l i ty plan can be generated, thefollowing questi ons should be addressed

1. What is to be produced?

2. How are the products to be produced?

3. When are the products to be produced?

4. How much of each product wi l l be produced?

5. For how l ong wi l l the products be produced?

6. Where are the products to be produced?


Relationship between product, process, and schedule

design and facilities planning


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Facility planning functions relationshipLinks between components:

ProductChange in the design of a product. Addition or deleting of a product. A significant increase in demand.

Process:Chang of the design of the process.Replacement of a machine.A adaptat ion of new standards.

Scheduling:

BottlenecksDelay and idle ti me.Excessive temporary storageObstacles to mat erial flow.High ratio of material handling time/ production t ime


Product Design (Identify)

Product design involves

the determinat ion of whi ch products are to be produced

the detailed design of i ndi vidual products.

Decisions regarding the products to be producedare generally made by top management based oninput f rom market ing, manufactur ing, and financeconcerning projected economic performance.


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Product Design (Identify)

I f it is decided that t he facil it y is to be designed toaccommodate changes in occupants and mission,then a hi ghly f lexible design is requi red and verygeneral space wil l be planned.

On the other hand, if i t is determined that theproducts to be produced can be stated wi th a highdegree of confidence, then the facility can be

designed to opt imize the production of thoseparticular products.


Product Design

Customer NeedsQFD Benchmarking

Product

Designer

Components

Product

Auto CAD

Exploded Assembly Drawing

Exploded Parts Photograph

Process & Assembly(Process Designer)

Finished

Customer


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Product Design involves:

Qualit y fun ction deployment (Q F D)

House of quali ty (H O Q)

Benchmarking

Design for m anufactur ing and

assemb ly (D F M A)

Prototypin g (The fir st testing patt ern )

Exploded assembly dr awing

Photography

CAD drawing


M anuf acturing w as once relat ively simple:

CAD: computer aided design

CAM: comput er aided manuf acturing

CI M: computer int egrat ed manuf acturing

FMS: f lexible manuf acturing syst ems

FAS: f lexible aut omated systems

FMC: f lexible manuf acturing cell

GT: group technology

JI T: just in time manuf act uring

SQC: stat istical quality cont rol

TQ C: t ot al quality cont rol

To a RubicRubic cube ofcube of

manufact uringmanufact uring

I t has gone f rom simple L ego assembly


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Exploded Assembly DrawingExploded Assembly Drawing


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Exploded Assembly DrawingExploded Assembly Drawing


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Process DesignHow the product is going to be produced, on whi ch machin e,make or bu y decision, how long it will t ake to perform t he

operation.

Basicall y process design consists of 3 stages:

1. Identi fying the requi red process

I. make-or-bu y decision

II . part list

III. bill of materials

2) selecting t he requ ir ed processes

I. process selecti on procedure

II . rou te sheet

3. sequencing the requi red processes

i. assembly chart

i i . operation pr ocess char t

i i i. Precedence diagram


Make or Buy Decision

BOM Purchase

Make

Process

Identification

Route

Sheet

CAPP CADProcess

Selection

Assembly Chart

Components

Sub Assemblies

Assemblies

Packaged Product

Operation

Process

Chart

Precedence

Diagram

Liaison

Sequence

Analysis

1 & 11

Group

Technology

Operations

Equipment

Production

times

Utilizations

Alternatives

Result

Figure

3.10 or

Process selection& Design pr ocess


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Determi nes whether

a particular

product,

subassembly or part

is produced in

hou se or

subcont racted to

outside suppl ier or

contractor.

M ake or Buy D ecision ProcessM ake or Buy D ecision Process


Pr ocess I dentification

Define elemental operations Step1

Identify alternative processes for each operation Step2

Analyze alternative processes Step3

Standardize processes Step4

Evaluate alternative processes Step5

Select processes Step6

Figure 3.10 Process selection procedure

Computer Aided Process Planning (CAPP)-Variant-Generative


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After the make or buy decisions have been made,a li st of i tems to be made and the it ems to bepurchased wil l be determined.

The li sti ng often takes the form of a part s li st ora bil l of mater ials. A parts l ist i ncludes at leastthe foll owing

1. Part numbers

2. Par t name

3. Number of parts per product

4. Drawing

After Make or Buy decision


Process Design

A par t l ist

1 ) part number

2) part name

3) number of parts

4 ) dra wing number

5) material

6 ) size

7) quantity

8 ) make or buy


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Bi ll of mat erialBi ll of mat erial

Structu red part list

= part list + level

Level 0: final product

Level I: subassembl ies and component s that feed directly i nt o level

H ow to const ruct it ?


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Selecting the Required Pr ocesses

After determining in house parts, decisions areneeded as to how the products wi l l be made:

previous experiences

related requi rement s

avai lable equipment

producti on rates

fu tur e expectat ions.

Outputs are processes, equipment, and rawmater ials requi red for t he in-house production ofproducts, also called a route sheet .


Route sheet

The outputs from the process selection procedure arethe processes, equipment, and raw materials required

for in-house production of products. Output is

generally given in the form of a rout sheet.

It lists, in addition to part information, the related

operations for each make component.


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Sequencing the Required Process

The method of assembling a product is

accomplished by the assembly chart.

Assembly char tshows the sequence of

operations in putting the product together.

The easiest method of const ruct ing anassembly char t is to begin with thecompleted product and t race the product

disassembly back to its basic components.


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Assembly Chart

The easiest way of

constructing anassembly chart is tobegin wit h t hecompleted productand to tr ace th eproduct disassembly

back t o its basiccomponents

H ow to construct it ?


Although route sheets provide

informat ion on product ion methods andassembly charts indicate how component sare combined, neither provides an overall

understanding of the flow within thefaci li t y. Thi s is accompl ished wi th theoperation process chart .



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To provide anovervi ew of

th e flowwithin thefacilit y weimpose the

rou t sheet onth e assemb ly

chart. Theresultingchart is

referr ed to as

an operationprocesschart .

Operation pr ocess chart -----analog model ofoverall product ion process




A second viewpoin t (from graph and network

theory) is to interpret t he charts as networkrepresentati ons, or more accurately, t reerepresent ations of a production process.

A vari ation of the network viewpoint is to treat theassembly chart and the operations process chart asspecial cases of a more general graphical model,the precedence diagram.


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A network representationof all processes need toexecuted successively.

The diagram can be ofsignificant benefit t o th e

facili ti es planner. Itestablishes th e precedencerelationships that mu st be

maintained inmanufacturingand

assemblin g a produ ct .

Precedence diagram



Flow Process Chart

This chart uses circles for

operations, arrows for transports,

squares for inspections, triangles

for storage, and the letter D fordelays. Vertical lines connect these

symbols in the sequence they are

performed.


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E xample 1

E xample 2

Example

Develop an assembly chart foradvertisement pen

Group work



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Schedule Design

Schedule design decisionsprovide answers toquest ions involv ing howmuch to produce and when

to produce.

Production quanti tydecisions are r eferred to aslot size decisions

Determining when toproduce is r eferr ed to asproduct ion schedul ing.

How does a schedule design impact the facility design?

Schedule design decisions impact;

Machine selection

Number of machines

Number of shifts

Number of employees

Space requirements

Storage equipment

Material handling equipment

Personnel requirements

Storage policies Unit load design

Building size

And more


Schedule Design

Schedule design determ ines:

How much to produce

When to produce

How long production will continue

lot size decision

production scheduling

market forecast

Two sources1. Market information

- production rate

- production rate change (trend)

- production cycle

- volume- variety relationship

2. Process requirement- number of machines

- scrap rate (scrap estimation)


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Schedule Design

Variety

Product

PlanningDepartment

FixedMaterial

Location

Planning

department

Product

FamilyPlanning

department

Process

Planning

Department

Low

Medium

High

Processlayout

Productlayout

GT layout

Fixed locationlayout

Low Medium High

Volume


VOLUME

VOLUME

VARIETY

VARIETY

10K

100K

Process-orientedsystem

Product- Oriented

System

Schedule Design


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Schedule Design (Marketing)

Mark eti ng depart ment provides a research function thatanalyzes what the wor ld s consumer wants. Some of t heinformat ion that marketi ng provides is:

Selling price

Volume, how many can we sell?

Seasonali ty, summer or winter product

Replacement parts, older products

Valuable information that should be obtained from

marketing and used by a facil i t ies planner. See Table 2.4


Scrap Estimation

Total production = mark et estimate + scrap estimate

Scrap = reject - rework

How is scrap calculated?

Let Pk: represent the percentage of scrap produced on the kth operation

Ok: the desired output of non-defective product from operation k

Ik: the production input to operation k.

It follows that, on the averageOk= Ik- PkIkOk= Ik(1 - Pk) , Hence,

Ik= Ok/ (1 Pk)

Thus, the expected number of units to start into production for a part having n

operations is

In = On/ (1 - P1)(1 - P2) ... (1 - Pn)

IP1 P2 P3

O

I1 O1

P 1


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ExampleQ) A product has a market estimate of 97,000 components and requires three

processing steps (turning, milling, and drilling) having scrap estimates of P1= 0.04, P2 = 0.01, and P3 = 0.03.

SolutionThe market estimate is the output required from step 3. Therefore, 97,000O3 = 97000 = X* (1 - 0.03) , i.e., X=100,000=I3 . Assuming no damage between

operations 2 and 3 and an inspection operation to remove all rejects, theoutput of good components from operation 2 (Q2) may be equated to theinput to operation 3 (I3). Therefore, the number of components to start intooperation 2 (I2) is

100,000 =I3 =Q2 = Y * (1 - 0.01), i.e., Y=101,010 unit =I2Likewise, for operation 1:

101,010 = I2 = Q1=Z * (1 - 0.04), i.e., Z=105219 unit =I1The calculations are identical to:

97,000 / (I - 0.03)(I - 0.01)(I - 0.04) = 105,219

I

0.040.01

0.03

97000

1 2 3


"What if" there is a rework:

I O1-P1

P 1

P 2

1

2

a. Back stream

IO1-P1

P1

P 2

1

2

b. Up stream

O = I * YieldTC = ?QZ


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"What if" there is a rework:

a. Back st ream

O = I (1-P1)+ I P1(1-P2) (1-P1)+ I P1(1-P2) P1 (1-P2) (1-P1) +

.

O = I (1-P1) [ 1+ P1(1-P2)+ P12 (1-P2)

2 + ]

Let a= P1(1-P2)

O = I (1-P1 ) (1+a+a2+a3+..)

O = I (1-P1 ) / (1-a)O = I * Yield

Total Cost = C1 I +C2 I P1 + C1 I P1 (1-P2) + C2 I P1(1-P2)P1+.

TC= C1* I/ (1-a) +C2*I*P1/ (1-a)

I O1-P1

P 1

P 2

1

2


"What if" there is a rework

b. Up stream

O = I (1-P1) +I P1 (1-P2) + ?

TC = I C1 + I P1 C2 + ?

IO1-P1

P 1

P 2

1

2


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Example Compare for the back stream andupstream if P1=0.2 and P2=0.7,C1=JD 2 and C2=JD 7 and 100good units are required

Back stream analysis

Find a = 0.2(1-0.7) = 0.06

The yield= (1-P1)/(1-a) = 0.85

I = 100/0.85= 117.5 =118

Upstream Analysis

O = I (1-P1) +I P1 (1-P2)

100 = I [ (1-0.2) +0.2(1-0.7)]

100 = I [0.8 + 0.06]

I= 100/0.86 = 116.3=117

Compare for the back stream andupstream if P1=0.7 and P2=0.2 and100 good units are required

Back stream analysis

Find a = 0.7(1-0.2) = 0.56

The yield= (1-P1)/(1-a) = 0.682

I = 100/0.682= 146.6 =147TC = JD 3190

Upstream Analysis

O = I (1-P1) +I P1 (1-P2)

100 = I [ (1-0.7) +0.7(1-0.2)]

100 = I [0.3 + 0.56]

I= 100/0.86 = 117

TC = JD 807

TC= C1* I/(1-a) +C2*I*P1 /(1-a) = JD 362

TC = I C1 + I P1 C2 = 200+140 = JD 340


Equipment Fraction

The quant it y of equ ipment requ ired for an operation is r eferred toas equipment fraction.

The following determi ni stic model can be used to esti mate theequ ipment fraction requ ired.

F =

S * Q

E * H * R

Where:

F= number of machines required per shift

R=reliability of machine (percent up time)

Q= number of units to be produced per shiftE= efficiency

H=amount of time (min) available per machine

S= standard time (min) per unit produced


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ExampleA machined part has a standard machinery time of 2.8 min per part on a

milling machine. During an 8-hr shift 200 units are to be produced. Of the480 min available for production, the milling machine will be operational80% of the time. During the time the machine is operational, parts areproduced at a rate equal to 95% of the standard rate. How many millingmachines are required?

Solution

For the example,

S = 2.8 min per part

Q = 200 units per shift

H = 480 min per shift (8X60)

E = 0.95R = 0.80

Thus, F = 2.8(200) /0.95(480)(0.80) = 1.535 machines per shift


What if

S * QF=

(H-Tset-Tmain) * R *E

F tot = FI +Fset +Fmain from I=1 to n

Fset up = nu mber of setu ps *Time per setu p

Available tim e

rout ing effect

Shift

Fmain = nu mber of main tenance *

Maintenance time

Available ti me

maintenance

Setu p tim e

Option 1

Option 2


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ExampleMachine A Machine B

Time per min 8 hrs /5day/w 8 hrs /5day/w

Efficiency 0.95 0.95

Reliability 0.9 0.9

St Time X 5 10

St Time Y 2 4

Scrape X 5% 5%

Scrape Y 5% 5%

Given the following Table and information, Find the requiredmachine fraction for machine A and B if you know that

- Required output is X= 1000, Y= 2000

- Setup time is one per week (for X=25 and Y=50 Min)

- X routing is A then B and Y routing is B then A

- Maintenance after 500 units for 25 min

- 8 hrs/5day/w is available time for each machine

Solution

F tot= F routing + F setup + F maint.

A machine: QAX = 1000/ (1-0.05)(1-0.05) = 1108QBY = 2000/ (1-0.05 )(1-0.05) = 2217

1000

2000

A

B

B

A

1053

1108

2106

2217

FA-routing = FAX + FAY= (S.Q/HRE) = 5*1108/ (0.9)(0.95)(5*8*60) + 2*2106/ (0.9)(0.95)(5*8*60) =4.75FA-setup = F setup-Ax + F setup-Ay = (1)*25 min /2400 + (1)*50 min /2400 = 0.03

FA-maint. = (1108 +2106)/(500) * (25 min/2400) =0.07

FA = 4.85 ~ 5 machines

FB = 9.55 ~ 10


7 management and planning tools

The seven management and planning tools are

1. The affinity diagram,

2. The interrelationship digraph,

3. The tree diagram,

4. The matrix diagram,

5. The contingency diagram,

6. The activity network diagram, and

7. The prioritization matrix.


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Affinity Diagram

The affinity diagram is used togather language data, such asideas and issues, and organize itinto groupings.

Suppose we are interested ingenerating ideas for reducingmanufacturing lead time. In abrainstorming session, the issuesare written down on "post-it"notes and grouped on a board orwall. Each group then receives aheading. An affinity diagram forreducing manufacturing lead timeis presented in Figure 2.19.

facilitiesdesign

equipmentissues

qual i t y set -up time scheduling

1.

2.

3.

1.

2.

3.

4.

5.

1.

2.

3.

4.

1.

2.

3.

4.

1.

2.

3.



Interrelationship Digraph

The interrelationship digraph is used to map thelogical links among related items, trying toidentify which items impact others the most.The term digraph is employed because thegraph uses directed arcs. Suppose we want tostudy the relationship between the items inFigure 2.19 under facilities design. Theinterrelationships are presented in Figure2.20. Note that this graph helps us understandthe logical sequence of steps for the facilities

design.

Tree Diagram

The tree diagram is used to map in increasingdetail the actions that need to beaccomplished in order to achieve a generalobjective. Assuming that we want toconstruct a tree diagram for the formation ofproduct families, the tree is presented inFigure 2.21. Note that the same exercise canbe performed for each item in theinterrelationship digraph.


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Matrix Diagram

The matrix diagram organizesinformation such as characteristics,functions, and tasks into sets of itemsto be compared. See Table 2.10

Contingency Diagram

The contingency diagram, formallyknown as process decision programchart, maps conceivable events andcontingencies that might occur duringimplementation. It is particularlyuseful when the project being plannedconsists of unfamiliar tasks. Thebenefit of preventing or responding

effectively to contingencies makes itworthwhile to look at thesepossibilities during the planningphase.

Man Mach in e Material

Product 1 x1 y1 Z1

Product 2 x2 y2 Z2

Product 3 x3 y3 Z3


7 management and planning toolsActivity Network Diagram

The activity network diagram is used to develop a workschedule for the facilities design effort. This diagram issynonymous to the critical path method (CPM) graph. Itcan also be replaced by a Gantt chart and if a range isdefined for the duration of each activity, the ProgramEvaluation and Review Technique (PERT) chart can alsobe used. The important message is that a well thought outtime table is needed to understand the length of thefacilities design project. This timetable can be developedafter the actions on the tree diagram have been evaluatedwith the prioritization matrix. An example of an activitynetwork diagram for a production line expansion is

illustrated in Figure 2.22.

Prioritization Matrix

In developing facilities design alternatives it is important toconsider:

(a) Layout characteristics

(b) Material handling requirements

(c) Unit load implied

(d) Storage strategies

(e) Overall building impact

The prioritization matrix can be used to judge the relativeimportance of each criterion as compared to each other.Table 2.12 presents the prioritization of the criteria for thefacilities design example. The criteria are labeled to helpin building a table with weights.

A

2 0 5

0 5

B

3 2 5

2 5

F

4 2 6

6 10

C

5 5 10

5 10

A

2 0 5

0 5

A B C D E

A 1 5 10 1 1

B 1/5 1

C 1/10 1

D 1 1

E 1 1


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Facilities Design

Alternatives

1. Layout

2. Handling

3. Storage

4. Unit load design

Facilities Planner

DesignProduct Process

Decisions

Evaluate

Organizational Objectives

7 Management & Planning tools

Affinity DiagramInterrelationship diagraph

Tree diagram

Matrix diagram

Contingency diagram

Activity network diagram

Prioritization matrix

Facility Planning Tools

Pareto Charts

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