Product and Equipment Analysis

1
Product and Equipment Analysis

• Chapter 2

2
Data required for developing good layouts

• Product Analysis
• Process Analysis

3
Input Data and Activities

• What data are critical to the facility plan?
• Muther categorizes the information as
• P Product (what?)
• Q Quantity (how much?)
• R Routing (where?)
• S Support (with what?)
• T Timing (when?)

4
Product Analysis

• Bill of Materials
• Assembly Charts
• Engineering Drawing
• Operation Process Chart
• Route Sheet

5
Input Data and Activities

• Tompkins, White, et. al., categorize it as
• Product Design what is to be produced?
• Process Design how is it to be produced?
• Schedule Design when and how much?

Product
Facility
Schedule
Process
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Product Design

• Based on
• Function
• Aesthetics
• Costs
• Materials
• Manufacturing Methods
• Key point
• The product design MUST be finalized before
  designing the facility. Otherwise a flexible
  facility is needed.

Driven by market demand
7
Tools Used in Product Design

• Product/Part Drawings
• 2-D, 3-D visualization

• Exploded Assembly Diagrams

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Part drawing
9
Tools Used in Process Design

• A partial list (dependent on product and
  service)
• Process Flowcharts and Process Maps
• Make vs. Buy
• Parts Lists
• Bill of Materials
• Route Sheets
• Assembly Charts
• Operations Process Charts
• Precedence Diagrams

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Process Flowcharts
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Process Maps
Customer Waiter Salad Chef Dinner Chef
N
Place order
Y
Give soup or salad order to chef
Prepare dinner order
Give dinner order to chef
Drink
Get drinks for customer
Eat salad or soup
Deliver salad or soup order to customer
Give order to waiter
Deliver dinner to customer
Eat dinner
Receives check
Deliver check to customer
Gives payment to waiter
Receive payment for meal
Credit
Cash or Credit?
Cash
Collect change, leave tip
Bring change to customer
Run credit card through
Fill in tip amount
Return credit slip to customer
Collect tip
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Make vs. Buy?
BUY
No
Is it cheaper for us to make?
Yes
Can we make the item?
Yes
Yes
Can item be purchased?
Is the capital available?
No
No
Yes
No
MAKE
BUY
BUY
MAKE
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Parts List

• A listing of component parts.

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Bill of Materials

• Many different types of structured parts lists

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Bill of Materials
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Route Sheet
Company ARC Inc. Produce Air Flow Regulator
Part Plunger Housing Part No. 3254
Prepared by JSU Part No. 6/6/03
17
Routing sheet
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Assembly Chart

• Analog model of the assembly process.
• Circles denote components
• Links denote operations/subassemblies
• Squares represent inspections operation
• Begin with the original product and to trace the
  product disassembly back to its basic components.

I-1
1050
Pack
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Assembly Charts
1
4
2
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Symbols for 5 basic mfg activities
21
Operation process chart for 3.5 volt halogen
otoscope
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Found by superimposing the route sheets and the
assembly chart, a chart results that gives an
overview of the flow within the facility.
Operations Process Chart
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Volume Variety Charts
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Volume Variety Chart
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Production Requirements Yield Loss
Pi Production input to operation i si
Fraction of Pi lost (scrap) Oi output of
process i
i
Oi
Pi
Pisi
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Production Requirements Series Systems
. . .
1
2
n
On
P1
Pnsn
P1s1
P2s2
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Example

• 5 processes in series
• Need 2000 units out

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Production Requirements Non Series
Part B
Part A
Work backward from end of the line.
100,000 units
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Simple equipment selection model

• P desired prod rate
• t time (in hours)
• to process one part
• m/c avail time (in hours)
• m/c efficiency

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Simple equipment selection model

• Nol Number of good units at output of stage l
• Nil Number of units reqd at input of stage l
• Sl Scrap at stage l

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Simple example

• 1. Consider a simple jobshop manufacturing system
  that makes three major Class A products
  requiring five types of machines. The three
  products include seven parts shown in Table 2.1.
  Table 2.1 also shows the time standards in units
  per hour.
• 2. Assume we an hour has only 55 minutes of
  productive time and that 5 minutes are lost due
  to operator or machine unavailability and machine
  downtime.
• 3. Dividing the value 55 by the values in Table
  2.1, we get the as well as time per unit.
• 4. Determine the quantities of machines of each
  type required to make the standard time per unit.
• 5. Assuming 12000 representative parts are to
  be made and that only 440 minutes of productive
  time is available per shift, we can find that we
  need 4.9 units of machine A, 5.85 units of
  machine B, and 4.3 units of machine C.
• 6. Rounding up these numbers gives us 5, 6, and 5
  units of machine types A, B, and C, respectively.

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Table 2.1
33
Table 2.2
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Calculating Equipment Requirements

• How many pieces of equipment do we need?
• Pi Production rate for operation i (pcs/period)
• Ti Time per piece for operation i (time/pc)
• Ci Time available to run operation i
  (time/period)
• Ei Efficiency of machine while running
• Ri Reliability of machine
• Mj Number of type j machines required
• xj Set of operations run on machine j

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Example

• Consider Machine 2
• x22,3
• Do similar calculation for other machines
• Other factors to consider
• Number of shifts
• Setup times
• Customer lot sizes (smaller require more setups)
• Layout type
• Maintenance activities

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Operator-Machine Charts

• Tool for showing activity of both operator and
  machine along a time line
• Also called multiple activity chart
• Example
• 1 minute to load
• 1 minute to unload
• 6 minute run cycle
• 0.5 minute to inspect and pack
• 0.5 minute to travel to another machine

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Operator Machine Charts
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Parameters for an LP equipment selection model

• Oi Operation type i, i1,2,...,o
• Mi Production equipment type i, i1,2,...,m
• Pi Part type i, i1,2,...,p
• MHi Material handling system type i, i1,2,...,n
• cij cost of performing operation Oi on production
  equipment type Mj
• hij cost of handling part type Pi using material
  handling system type MHj
• tij time required to perform operation Oi on
  production equipment type Mj
• sij time required to transport part type Pi using
  material handling carrier type MHj
• tj time available on production equipment type Mj
• sj time available on material handling carrier
  type MHj
• NOi number of operations Oi to be performed
• NPi number of units of part type Pi to be
  manufactured
• Cj cost of production equipment type Mj
• Hj cost of material handling system MHj
• B total budget available

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Decision Variables for LP equipment selection
model

• xij number of operations Oi to be performed on
  production equipment type Mj
• yij number of units of part type Pi to be
  transported on material handling system type MHj
• NMj number of units of production equipment type
  Mj selected
• NMHj number of units of material handling system
  type MHj selected

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LP equipment selection model

• Min
• Subject to

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LP equipment selection model (cont)
42
Example

• An automobile engine cylinder manufacturing
  company that supplies high precision engines to a
  multinational car manufacturer plans to
  manufacture several models of cylinder.
• For planning purposes, it uses the following
  pseudo products - a standard engine cylinder, a
  high-technology model, an engine cylinder for
  sports cars and a luxury car cylinder.
• The marketing department has demand forecast
  figures which have been aggregated for the four
  pseudo models. It has been determined that 2000,
  1500, 1800 and 1000 units of the basic,
  high-tech, sports and luxury models will be
  demanded during the next six months.

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Example

• The models require one or more of three
  operations, referred to as O1, O2, and O3.
• Three machine types and two material handling
  systems available for performing the three
  operations and transporting the models. These are
  denoted as M1, M2, M3 and MH1, MH2, respectively.
• Each machine and handling system may be assumed
  to be available for 90 percent of the time.
• The cost of machines M1, M2, and M3 are
  230,000 250,000 310,000
• The cost of material handling carriers MH1, MH2
  are 90,000 and 130,000
• The available budget is 10,000,000.
• The following two matrices show the cij's and
  hij's - that is, the cost of performing operation
  Oi on production equipment type Mj and cost of
  handling part type Pi using material handling
  system type MHj, respectively.

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Data for example
45
LP Model for example

• MIN 90000 NMH1 130000 NMH2 230000 NM1
  250000 NM2
• 310000 NM3 6 X11 12 X12 8 X13 4
  X21 5 X22
• 4 X23 12 X31 5 X32 5 X33 10 Y11
  5 Y12 12 Y21
• 6 Y22 18 Y31 9 Y32 6 Y41 3 Y42
• SUBJECT TO
• C1) X11 X12 X13 gt 200
• C2) X21 X22 X23 gt 200
• C3) X31 X32 X33 gt 150
• C4) - 300 NM1 1.67 X11 2.5 X21 0.83
  X31 lt 0
• C5) - 300 NM2 0.833 X12 2 X22 2 X32
  lt 0
• C6) - 300 NM3 1.25 X13 2.5 X23 2
  X33 lt 0
• C7) Y11 Y12 gt 2000
• C8) Y21 Y22 gt 1500
• C9) Y31 Y32 gt 1800
• C10) Y41 Y42 gt 1000
• C11) - 300 NMH1 0.1 Y11 0.0833 Y21
  0.056 Y31 0.167 Y41 lt 0
• C12) - 300 NMH2 0.2 Y12 0.167 Y22
  0.11 Y32 0.33 Y42 lt 0
• C13) 90000 NMH1 130000 NMH2 230000
  NM1 250000 NM2
• 310000 NM3 lt 1000000

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LP Model Solution

• VARIABLE VALUE REDUCED COST
• NMH1 2.000000 90000.000000
• NMH2 .000000 105454.546875
• NM1 2.000000 228562.875000
• NM2 1.000000 248353.593750
• NM3 .000000 308353.593750
• X11 200.000000 .000000
• X12 .000000 2.571524
• X13 .000000 .860030
• X21 59.880245 .000000
• X22 140.119751 .000000
• X23 .000000 1.744012
• X31 140.119751 .000000
• X32 9.880246 .000000
• X33 .000000 .000000
• Y11 2000.000000 .000000
• Y12 .000000 11.363637
• Y21 1500.000000 .000000
• Y22 .000000 7.663636

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Parameters for LP equipment selection model

• rik number of times operation Oi is to be
  performed on part type Pk
• cijk cost of performing operation Oi using
  production equipment type Mj on part type Pk
• tijk time required to perform operation Oi using
  production equipment type Mj on part type Pk
• xijk number of units of operation Oi performed
  using production equipment type Mj on part type
  Pk
• Cj purchase cost of production equipment type Mj
  prorated over the planning period

48
LP equipment selection model

• Min
• Subject to

49
Queuing Model

• Manufacturing engineers at the Widget
  Manufacturing Company recently convinced their
  manger to purchase a more expensive, but flexible
  machine that can do multiple operations
  simultaneously.
• The rate at which parts arrived at the machine
  that was replaced by the flexible machines
  follows a Poisson process with a mean of 10 parts
  per hour.
• The service rate of the flexible machine is 15
  units parts per hour compared with the 11 units
  per hour service rate of the machine it replaced.
  (All service times follow an exponential
  distribution.)

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Queuing Model

• The engineers and manager were convinced that
  the company would have sufficient capacity to
  meet higher levels of demand, but just after a
  two months of purchasing the machines it turned
  out that the input queue to the flexible machine
  was excessively long and part flow times at this
  station were so long, that the flexible machine
  became a severe bottleneck.
• The engineers noticed that more parts were
  routed through this machine, and that the parts
  arrival rate to the flexible machines had
  increased from 10 per hour to about 20 per hour,
  but were puzzled why the part flow time at this
  station doubled from 30 minutes to one hour and
  the work-n-process (WIP) inventory increased
  nearly threefold from 5 o 14 when the arrival rte
  only increased 40.
• Use a queuing model to justify the results
  observed at Widget Manufacturing Company.

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M/M/1 Model Solution
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Personnel requirements analysis

• n number of types of operations
• Oi aggregate number of operation type i required
  on all the pseudo (or real) products manufactured
  per day
• Ti standard time required for an average
  operation Oi
• H total production time available per day
• ? assumed production efficiency of the plant

53
Queuing Model

• The American Automobile Drivers Association
  (AADA) is the only office serving customers in
  New Yorks greater capital district area. Ahead
  of the busy summer season, the office manager
  wants to hire additional staff members to help
  provide these services to members effectively -
  summer travel planning, membership renewal,
  disbursing travelers checks, airline, hotel, and
  cruise booking, and other travel related
  services.
• It is anticipated that each customer typically
  requires 10 minutes of service time and customers
  arrive at the rate of one customer every three
  minutes.
• The arrival process is Poisson and the service
  times are exponentially distributed.
• Determine how many staff members are required if
  the average wages and benefits per staff member
  are 20 per hour and the cost to AADA for every
  hour that a customer waits to be served is 40.

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M/M/m Model Solution
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Production space requirement sheet