23364211 Production Mgt Design for Manufacture and Assembly
Transcript of 23364211 Production Mgt Design for Manufacture and Assembly
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DFMA ± Design for Manufactureand Assembly
Shin Ta LiuPh.D. CSSBB, CQE, CRE
Principal Consultant
Lynx Systems
12529 Cloudesly Dr
San Diego, CA 92128
Web site: www.lynxsys.net
Email : [email protected]
Phone: 858-366-4951
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DFSS Process
DCDOV
Goals Tools
Define Obtain customers needs and wants
Translate customers needs andwants to VOC list
Market/Customer Research, Kanoanalysis, stakeholders analysis,operation cross walk
Concept Development Develop DesignFeature/functional requirementsbased on VOC
QFD. TRIZ, Axiomatic Design
Design Development Identify engineering andprocess parameters based onthe design features/functionalrequirements
CTX, DFX, DOE, Taguchimethods
Optimize Design Identify optimal settings for theengineering and processparameters based on theperformance, robustness,production and other requirements.
RSM, FMEA update, sensitivityanalysis, Taguchi Methods
Verify Capability Establish the designedproduct/process is capable of
meeting the design target andrequirements.
Verification/qualification tests,validation tests, simulation,
statistical analysis
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DFMA process
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DFMA Algorithm
Determine criticality of a part
a part is critical if
± - move relative to all other parts already assembled, or ± - different material than all being assembled
± - separated from other parts assembled.
Physical coupling of ³un-critical parts with a ³criticalpart´
Reassess assembly time for new configured parts Analyze the manufacturability of new configured part
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DFMA Example
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DFMA Example 1 Analysis
Total actual assembly Time T1= 163 s
Theoretical total part count is 4 and averageassembly time is 3 s. Theoretical assembly
time T2= 4 x 3 s = 12 s Calculate Design Efficiency :
or 7.362%
07362.0163
12
1
2!!!
s
s
T
T L
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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.
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DFMA- An Improved DesignDFMA- An Improved Design
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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
AssemblyTime(s)
TheoreticalPart Count
Number Item
8.5
- - Thread leads 5.0
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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 (includetooling)
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
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DFMA ±Calculate Total Saving
Total Saving =
Saving from Assembly Time Reduction+ Saving from parts reduction
= $0.95 + $13.71
= $14.66
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Improved Assembly Design Efficiency
Total actual assembly Time T1= 46 s
Theoretical total part count is 4 and averageassembly time is 3 s. Theoretical assembly
time T2= 4 x 3 s = 12 s Calculate Design Efficiency :
or 26.087%
26087.046
12
1
2!!!
s
s
T
T L
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Design for Assemblability &
Manufacturability-Summary
Design Guides:
Minimize the number of setup and stages. Analyze the existing manufacturing and assembly function. Revisit the physical structure (of the design) which customize
to the local processing capability Apply the most appropriate (not latest) technology.
Use Axiomatic design to create Modular design of the parts. Design for minimum number of parts using physical coupling Choose the appropriate material for easy manufacturing Apply the layer assembly principles.