04/18/23 IENG 471 Facilities Planning 1

IENG 471 - Lecture 04

Schedule Design

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Agenda

AssignmentsSchedule Design

Required DataEstimating Production VolumeEstimating Equipment Needs (Equip. Frac.)Facilities Project Management Tools

Questions & Issues

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Assignments

Current Assignment: HW: (HW 2)

Product BOMProduct Operation Process ChartProduct Precedence Diagram

Next Assignment: HW: (HW 3) See Assignment Link

required input for each of the workstationsequipment necessary for each machinesteady state cycle time for each machineideal machine assignment for each machinecompute the idle time unit cost at each workstationtotal cost per good unit square footage for each workstation and the total space required

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Schedule Design Overview

Schedule Design is undertaken to decide for a facility design:How much should the facility be designed

to produceWhen should the facility be able to produce

the product

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Impacts of the Schedule Design:

The Schedule Design of the facility will impact:Types of machines required

Processing equipmentStorage equipmentMaterial handling equipment

Number of machines requiredNumber of employees requiredSpace requirements

For all of the above, plus support functions (services, utilities, …)

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Information Req’d: Marketing

What products are to be producedWhat volume of each product is

expected to be produced (and when)How probable are the production requirementsSeasonality and life cycle considerations

Where are the products to be acquiredWho will acquire the productsWhat are the product development plans

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Types of Manufacturing Systems:Job ShopBatch/CellularMass Production

Approximate Annual Volume:

Production Volume

Type of Production No. Produced Typical Products

Prototype 1 - 10 Anything

Piece/Small Batch 10 - 5,000 Aircraft, Machinery, Dies

Batch/High Volume 5,000 - 100,000 Trucks, Ag. Equip., Engines

Mass Production Over 100,000 Cars, Appliances, Fasteners

Kalpakjian

Job Shop

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Type of Production System

Job Shop Batch Prod. Mass Prod.

General Equipment Special

Production Rate

Production Quantity

Process Plant Layout Flow Line

Labor Skill

Part Variety

Characteristics

Kalpakjian

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Example Job Shop Layout

Drill

V. Mill

Lathe L. PaintOven

H. Mill

P. Paint

Drill

Drill

Drill

Lathe Lathe

Lathe

V. Mill

V. MillV. Mill

H. Mill

H. Mill

H. Mill

Grind

Grind

CMM

Receiving

Shipping

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Example Mass Production Layout

DrillV. Mill

L. Paint

Oven

Drill

Lathe

H. Mill

Grind

CMM

Receiving

Shipping

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Example Batch/Cell Production Layout

DrillV. Mill

L. Paint

Oven

Drill

Lathe

H. MillGrind

CMM

Receiving

Shipping

Drill

Grind

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Volume, Variety & AutomationP

rodu

ctio

n Q

uant

ity

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.

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Which Type to Use?: Pareto Chart

80% of any problem is the result of 20% of the potential causes*

Histogram categories are sorted by the magnitude of the bar

A line graph is overlaid, and depicts the cumulative proportion of products

Quickly identifies where to focus efforts

Pareto Chart for Product Volume

0

20

40

60

80

100

120

Pro

d A

Pro

d B

Pro

d C

Pro

d D

Pro

d E

Pro

d F

Pro

d G

Pro

d H

Product Type

Est

. Vo

lum

e R

eq’d

0%

20%

40%

60%

80%

100%

120%

Cu

mu

lati

ve %

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Estimating Production Volume with Scrap

The production facility must operate in the “real world” In the real world, things go wrong – defects!

To size the facility, the plant capacity must include extra volume for scrap: At a single workstation (k) the formula is:

where:Ik is the input amount required for the process to achieve goalsOk is the output amount required of the process, and Pk is the percentage of scrap generated by the process per unit

k

kk P

OI

1kkkk PIIO

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Estimating Production Volume with Scrap

Most processes are a sequence of operations We need to know the sequence and individual scrap rates of each of the

operations… Good thing we got those Operation Process Charts!

Assuming that each unit must go through each operation in a chain of operations, the plant capacity must include extra scrap volume: At end of a single chain of (n) individual operations, the formula for total

input volume required is:

where: On is the output amount required at the end of the operation chain, and Pk is the percentage of scrap per unit generated by the kth operation, starting

with operation 1 and continuing through operation n

nk

n

PPPPP

OI

1...1...111 321

Example 1: Express Input 1 as a function of the Quota

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1 2 3 4I1 O1=I2 O2=I3 O3=I4 O4=Q

P1=2% P2=5% P3=1% P4=0.5%

Example 2: Express Input 1 as a function of the Quota

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1 2 3 4

R

I1 O1=I2 O2+OR=I3

O3=I4 O4=Q

P1=2% P2=5%

PR=1%

P3=1% P4=0.5%IR OR

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1 2 3 4

R

I1 O1+OR=I2

O2=I3 O3=I4 O4=Q

P1=2% P2=5%

PR=1%

P3=1% P4=0.5%IR OR

Example 3: Express Input 1 as a function of the Quota

Example 4: Find Input 1 and the system Total Scrap Cost

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1 2 3I1 O1=I2 O2=I3 Q=1000

P1=3%S1=$5

P2=5%S2=$10

P3=7%S3=$15

Example 5: Find Input 1 and the system Total Scrap Cost (Note: Proportion scrap reversed from Example 4)

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1 2 3I1 O1=I2 O2=I3 Q=1000

P1=7%S1=$5

P2=5%S2=$10

P3=3%S3=$15