Embed Size (px)
Citation preview
Product, process and schedule Product, process and schedule design I.design I.
Plan of the lecture:◦Product design◦Process design◦Schedule design I
Product, process and schedule Product, process and schedule designdesign
Before we start developing alternative facility plans, we should have answers for the following questions
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 will be
produced?
5. For how long will the product be
produced?
6. Where will the products be produced?
Answer for the first 5 questions can be obtained from:
•Product design
•Process design
•Schedule design
Answer for the last question might be searched outside of the company -global sourcing effect
3
First five questions are answered by product design, process design, and schedule design respectively
The sixth question might be answered by facilities location determination, or
It might be answered by schedule design when production is to be allocated among several existing facilities.
Answering sixth question has become much more complicated lately.
Many firms have global production strategies and utilize combination of contract manufacturing and contract assembly.
Product, process and schedule Product, process and schedule designdesign
4
The textile industry, for example, has undergone tremendous change, with global sourcing occurring for yarn and textile production as well as for garment assembly.
The automobile industry is producing “world car”.
Engines power trains, bodies, electronic assemblies, seating, and tires may well be manufactured in different countries.
Home appliances, computer, television, with subassemblies and components being produced around the world.
Product, process and schedule Product, process and schedule designdesign
Product design:◦ Product designers determine:
Product specifications (dimensions, material, packaging, etc.)
Process design:◦ Process designers determine:
How the product will be producedSchedule design:
◦ Production planners determine: Production quantities The schedules for the equipment
WHERE DOES THE FACILITY PLANNER COME IN?
Product, process and schedule Product, process and schedule designdesign
Facility planner is dependent on timely and accurate input from product, process and schedule designers
The need for close coordination among the four groups
Determination of a product to be produced
Detailed design of the product
Based on input from:◦Marketing / Sales◦Manufacturing◦Finance◦Etc.
Most of the time final decisions are made by the top management
Product Design
Product Design – Product Product Design – Product DeterminationDetermination
Uncertainty regarding the mission of the facility
The occupants of the facility may change frequently or may never change at all◦If changes are likely – a high degree
of flexibility and a very general space◦If a high degree of confidence about
the products – the facility design should optimize the production of those products
The detailed design of the product is influenced by aesthetics, function, materials and manufacturing considerations
Quality Function Deployment - translation of the customers’ desires into product design, and subsequently into parts characteristics, process plans and production requirements.
Benchmarking – used to identify the approach of the competition
Product Design – Detailed Design
House Of Quality
How Much
CustomerRequirements
WHAT
Relationship matrix
ProductCharacteristics
HOW
MarketingCompetitiveassessment
CorrelationMatrix
Engineering Competitive Assessment
Quality Function Deployment - QFD
An Example with Completed QFD Matrices:
Product Planning Matrix for a Pencil
13
Value Analysis Following the product design, product
engineer, process engineer, industrial engineer, purchasing and marketing managers participate in a process known as value analysis or value engineering.
Each part of the product is analyzed in deep details to find ways to retain the quality of the part at the same level or higher, while making it in a cheaper way.
Ways like Substitute expensive raw material with less
expensive ones.Find raw material with their initial shape closer
to the final shape of the part.Relax tolerances.
Other factors affecting design - (Design for Manufacturing)Design for Manufacturing (DFM) and design for
assembly (DFA) are the integration of product design and process planning into one common activity. The goal is to design a product that is easily and economically manufactured.
GUIDELINES:◦ Reduce the total number of parts◦ Develop a modular design◦ Use of standard components◦ Design parts to be multi-functional◦ Avoid separate fasteners◦ Minimize assembly directions◦ Minimize handling
DFM - Example
◦ Minimize parts
◦ Design parts for multiply applications
◦ Use modular design
◦ Avoid tools
◦ Simplify operations
DFMA Example
DFMA-Example 1 Analysis
133.0 160.0 4 19 TOTALS
26.0 34.2 0 4 Cover Screw
7.9 9.4 0 1 Cover
3.8 4.5 - - Reorient
4.2 5.0 - - Thread lead
2.9 3.5 0 1 Plastic bush
13.8 16.6 0 2 End-plate screw
7.0 8.4 1 1 End plate
13.3 16.0 0 2 Standoff
8.8 10.6 0 1 Setscrew
7.1 8.5 1 1 Sensor Subassembly
17.5 21.0 0 2 Motor Screw
7.9 9.5 1 1 Motor Subassembly
10.2 12.3 0 2 Bush
2.9 3.5 1 1 Base
Assembly Cost (cents)
Assembly Time(s)
Theoretical Part Count
Number Item
DFMA Recommended redesign
Bushes are integral to the base Snap-on plastic cover replaces
standoff cover ,plastic bush, six screws.
Using pilot point screw to fix the base, which redesign to be self-alignment.
DFMA- An Improved DesignDFMA- An Improved Design
DFMA Worksheet for an Improved Design
38.4
3.3
7.1
7.1
10.0
3.8
2.9
Assembly Cost (cents)
4.2
46.0 4 7 TOTALS
4.0 0 1 Plastic Cover
0 1 Setscrew 8.5
1 1 Sensor Subassembly
12.0 0 2 Motor Screw
4.5 1 1 Motor Subassembly
3.5 1 1 Base
Assembly Time(s)
Theoretical Part Count
Number Item
8.5
- - Thread leads 5.0
DFMA Cost Differential Worksheet
Totals
Cover screw(4)
Cover
Plastic bush
End-plate Screw
Endplate
Standoff(2)
Setscrew
Motor Screw(2)
Bush(2)
Base (Aluminum)
Item
Old Design
21.73 35.44
0.40
8.00 Plastic Cover (include tooling)
8.05
0.10
0.20
5.89
5.19
0.10 Setscrew 0.10
0.20 Motor Screw(2) 0.20
2.40
13.43 Base (nylon) 12.91
Cost, $ Item Cost,$
New Design
DFMA –Calculate Total Saving
Total Saving = Saving from Assembly Time
Reduction + Saving from parts reduction = $0.95 + $13.71 = $14.66
Concurrent Engineering is a systematic way of enabling communication between all the related units during the product development
The aim is to minimize the changes in design parameters once the design is finalized
70% of the manufacturing cost is set during the design phase
Changing the design later in the process costs significantly more
Product Design – Detailed Design
Concurrent Engineering
Old “over-the –wall” sequential design process should not be used
◦ Each function did its work and
passed it to the next function
Replace with a Concurrent Engineering process
◦ All functions form a design team working
together to develop specifications, involve
customers early, solve potential
problems, reduce costs, & shorten time to
market
Cost of design changesCost of design changes
Design phase determines the most of the costs associated with delivering a product. Typically, 70-80% of the cost of a product is fixed at the design stage.
Tota
l C
ost
(%
)10
0
80
60
40
20
0Distribution, service, and disposal
Manufacturing
Detailed Design Prototype
Conceptual Design
Life-cycle cost committed
Cost incurred
Ease of change
Product Life-Cycle Includes
•Design Phase•Manufacturing Phase•Product usage phase•Disposal phase
Sequential development method
Concurrent development
method
Finally, detailed designs take place◦CAD designs◦Prototypes◦Assembly designs◦2D drawings and dimension
determinations
All these can be observed easily in most of the commercial CAD programs (AutoCAD, ProE, CATIA etc)
Product Design – Detailed Design
Once the product design is completed, usually following documents are provided for the facilities planning process as inputs◦Exploded assembly drawing – omits
specifications and dimensions◦Exploded parts photographs◦Component part drawing - detailed
Product Design - Documentation
Determination of how the product is to be produced◦ Who should do the processing? (Which part of
the products should be made?)◦ How the part will be produced?◦ Which equipment will be used? (for the parts
which will be made in-house)◦ How long will it take to perform the operation?
Production methods are the most fundamental factor affecting the physical layout
Process Design
Within the process design process, we need to consider following issues1. Process identification Make-or-buy analysis Parts identification
2. Process selection How the product will be made
(operations, equipment, raw material, etc.)
3. Process sequencing How components are put together
Process Design
Make-or-buy decisionsThe scope of the facility depends on the
level of vertical integrationHow are the make-or-buy decisions made?
◦ Can the item be purchased?◦ Should we go for subcontracting?
Supplier Contractor
◦ Can we make the item?◦ Is it cheaper for us to make than to buy?◦ Is the capital available so that we can make it?
Managerial decisions requiring input from finance, industrial engineering, marketing, process engineering, purchasing, human resources, etc.
Process Design – 1. Process identification
Process Design – 1. Process Process Design – 1. Process identificationidentification
The input to the facility planner is a listing of the items to be made/purchased.◦Parts list – component parts of a
product: part numbers part name number of parts per product drawing references
◦Bill of materials - structured parts list: contains hierarchy referring to the level of
product assembly
Process Design – 2. Process Process Design – 2. Process SelectionSelectionHow the products will be made
6-step procedure:1. Define elementary operations2. Identify alternative processes for each
operations3. Analyze alternative processes4. Standardize processes5. Evaluate alternative processes6. Select processes
Process Design – 2. Process Process Design – 2. Process SelectionSelection Computer Aided Process Planning (CAPP)
◦ Used to automate process planning◦ CAPP is the link between CAD and CAM◦ CAPP systems:
Variant process planning Standard process plans are stored in computer Called up whenever required Less expensive, easier
Generative process planning Process plans are generated automatically by the
computer No initial plan is needed
Input for the CAPP is CAD designs
Based on the design specification, CAPP ◦ can generate a number of alternative routes ◦ test them to obtain the best route
Process Design – 2. Process Process Design – 2. Process SelectionSelection
Data Production Example
Component name and number Plunger housing – 3254
Operation description and number Shape, drill, and cut off – 0104
Equipment requirements Automatic screw machine and appropriate tooling
Unit times (Per components) Set-up time: 5 hrs.
Operating time: 0.0057 hrs
Raw material requirement 1 in. diameter X 12 ft aluminum bar per 80 components
• Route sheet - output of process selection, it identifies processes, equipment and raw materials
Process Design – 2. Process Process Design – 2. Process SelectionSelection
Process Design – 3. Process Process Design – 3. Process SequencingSequencing
The method of assembling the product
Assembly chart – shows how the components are combined
Operation process chart – gives an overview of the flow within the facility◦A combination of route sheets and
assembly chartsPrecedence diagram – establishes
precedence relationships
Assembly ChartAssembly Chart
This was identified in route sheet
already
Inspection
Assemblies
Assembly operation
Inspection
Operation process chartOperation process chart
• Route sheet provides information on production methods
• Assembly chart determines how components are put together
• Operation process chart is a combination of route sheet and assembly chart
Manufactured component
Purchased component
Process Design – 3. Process Process Design – 3. Process SequencingSequencingPrecedence DiagramPrecedence Diagram
In the operation process charts, it is not clear if two machining operations have any dependency
Observe the part#3254
Operations 0204 and 0304 can be done at the same time
Yet, the operation 0104 should be completed before both 0204 and 0304
We cannot observe this information in operation process charts
How could such information effect decision for job scheduling?
Operation process chartOperation process chart
• Route sheet provides information on production methods
• Assembly chart determines how components are put together
• Operation process chart is a combination of route sheet and assembly chart
Manufactured component
Purchased component
Steps Documentation
Product design •Product determination
•Detailed design •Exploded assembly drawing•Exploded assembly photograph•Component part drawing
Process design •Process identification
•Parts list•Bill of materials
•Process selection •Route sheet
•Process sequencing
•Assembly chart•Operation process chart•Precedence diagram
Schedule design provides answers to questions involving:◦Production quantity - lot size decisions◦When to produce - production scheduling◦How long to produce
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, etc.
Schedule design
We design facilities for major parts and operations
What do we need to know to start designing our facilities◦Number of products to be produced◦Number of machines required◦Number of employees required◦Sequence of operations◦Relationships between departments
Schedule design
Objective – market estimateData from marketing:
◦Production volumes◦Trends◦Future demands
Min information provided by marketing:
Schedule design - Marketing information
Ideal information provided by marketing:
Qualitative information from marketing:
Volume-variety chart – Pareto lawVolume-variety chart – Pareto law85% of the
production volume is attributed to 15% of the production line
Therefore when facilities are designed, top 15% of the items that are produced should be considered the most
More general items produced everyday:
Mass production area
Items that are produced maybe by special orders etc.:
Job shop area
Volume-variety chart – Volume-variety chart – Pareto law does Pareto law does not applynot apply
If no products dominate the production flow, a general job shop facility is suggested
Specification of process requirements has three phases:◦Determination of the quantity to be
manufactured for each component Including the scraps!
◦Identification of each equipment required by each operation
◦Overall equipment requirements
Schedule design – Process Schedule design – Process requirementsrequirements
Based on the given system above, what is the minimum number of inputs required?
I = O+S If S is a fraction of I, then
Where Ps is the probability of producing scrap items
Process
Machining
Input
(I)
Output
(O)
Scrap (S)
Process requirements – Quantity Process requirements – Quantity determinationdeterminationScrap estimates – Scrap estimates – high volume productionhigh volume production
SP
OI
1IPOI S *
S = I* PS
Tin order to be able to produce the desired number of final products we have to consider the scraps from the beginning.
Total needed input can generally be computed using the following equation
)1)...(1)(1(21 nsss PPP
tFinalOutpuInput
Machining1
Input
(I)
Machining2
Scrap (S1)
Machining3
Machining4
Scrap (S2)
Scrap (S3)
Scrap (S4)
Final Product
Process requirements – Quantity Process requirements – Quantity determinationdeterminationScrap estimates – Scrap estimates – high volume productionhigh volume production
Scrap estimates - problemScrap estimates - problemMarket estimate of 97,000 components3 operations: turning, milling and drillingScrap estimates: P1=0.04, P2=0.01and P3=0.03
Total input to the production?
Production quantity scheduled for each operation?
219,105)04.01(*)01.01(*)03.01(
000,971
I
)1)...(1)(1(21 nsss PPP
tFinalOutpuInput
Scrap estimates - problemScrap estimates - problemProduction quantity scheduled for each
operation:
219,10504.01
000,101
000,10101.01
000,100
000,10003.01
000,97
1
2
3
I
I
I
Next lectureNext lectureSchedule design II
