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© IIGDT – Presentation at NACMA – October 8-9, 2012
International Institute of GD&TInternational Institute of GD&T
IIGDT
Dr. Greg Hetland, PresidentDr. Greg Hetland, President
International Institute of GD&TInternational Institute of GD&T
www.iigdt.comwww.iigdt.com
Profile Tolerancing: Proof of Compliance
vs Process & Design Feedback
Presented at NACAM - October 8-9, 2012
© IIGDT – Presentation at NACMA – October 8-9, 2012
Technology Challenges & ConstraintsMiniaturization & Tolerance Truncation
• Cycle-time Competing with Precision Requirements
Business Challenges & ConstraintsDecreasing Profit Margins
• Tolerances Decreasing - Bad Decisions Increasing
High-Risk IssueInability to represent functional intent through engineering
drawings and specifications.
Business & Technology Constraints
© IIGDT – Presentation at NACMA – October 8-9, 2012
What do we control on a mechanical part?(without getting down to Surface Roughness, Material Properties, Plating, etc.)
1. Size
Form
Orientation
Location
ASME Y14.5-2009
Is there a way to simplify this list of 4 items? What is controlled on a mechanical part other than:
Note: Surface Roughness is
defined in ASME B46.1-1995
Surfaces & Axes
ÍÂPosition controls derived AxesProfile controls Surface Geometries
© IIGDT – Presentation at NACMA – October 8-9, 2012
ASME Y14.5-2009, Section 8.2 Profile
Section 8.2 - Profile tolerances are used to define a tolerance
zone to control form or combinations of size, form, orientation, and
location of a feature(s) relative to a true profile. Depending on the
design requirements, profile tolerance zones may or may not be
related to datums. ……Where used as a refinement of size
tolerance created by toleranced dimensions, the profile tolerance
must be contained within the size limits.
Section 8.2.2 - The profile tolerance zone specifies a uniform or
nonuniform tolerance boundary along the true profile within which
the surface or single elements of the surface must lie.
© IIGDT – Presentation at NACMA – October 8-9, 2012
[Ö|).%|A]
[Ö|).!#|A]
[$X?@)]
What would your intent be?
Design Intent
requires that “ALL”
features
simultaneously lie
within their
respective
tolerance zones.
Four holes simply
fit over four pins
and the outside
surfaces of the
part (in the X/Y
plane) do not mate
up against other
parts.
Unless otherwise specified all dimensions are BASIC and controlled by the CAD model
© IIGDT – Presentation at NACMA – October 8-9, 2012
�Miniaturization & Tolerance Truncation
�Increased geometric complexity (complex curves)
�Cycle-time competing with precision requirements
Technology Challenges/Constraints Business Challenges/Constraints
�Industry profit margins are radically low
�Significant costs related to physical parameters
�Tolerances decreasing & bad decisions increasing
Technology
ConsultingTechnology
Consulting
GD&T
Uncertainty
Measurement
TechnologyMeasurement
Technology
3-DContact Non-Contact
Standards
TechnologyStandards
Technology
GD&T Metrology
Advanced
Tolerancing &
Metrology
Metrology
� Designers’ inability to represent functional intent (unambiguously) through
engineering drawings and specifications
� Individuals in manufacturing, quality and supply-chain not trained adequately to
interpret engineering drawings to optimally produce and deliver product
High Risk Issues
© IIGDT – Presentation at NACMA – October 8-9, 2012
© IIGDT – Presentation at NACMA – October 8-9, 2012
This revision contains paragraphs that give
stronger admonition than in the past that the
fully defined drawing should be
dimensioned using GD&T with limit
dimensioning reserved primarily for features
of size.
© IIGDT – Presentation at NACMA – October 8-9, 2012
Dimensioning & Tolerancing Standards
Other National Standards
• CSA – Canadian Standards
• DIN – German Standards
• GB – Chinese Standards
• ISO – ISO Standards
• JIS – Japanese Standards
• UNI - Italian Standards
• Etc…… the list goes on
Caution: Other National Standards are
not 100% equal to ASME Y14.5 Standard
; Í Î Ó Â ‰ (just to highlight a few)
© IIGDT – Presentation at NACMA – October 8-9, 2012
ProfileA profile tolerance specifies a uniform boundary along the true profile
within which the elements of the surface must lie. Where a profile
tolerance encompasses a sharp corner, the tolerance zone extends to the
intersection of the boundary lines. See the figure below.
Since the intersecting
surfaces may lie
anywhere within the
converging zone, the
actual part contour
could conceivably be
rounded. If this is
undesirable, the
drawing must indicate
the design
requirements, such as
by specifying the
maximum radius.
[Ö|).)%]
Outer Boundary
Inner Boundary
0.05
© IIGDT – Presentation at NACMA – October 8-9, 2012
[Ö|).)%]
Outer Boundary
Inner Boundary
0.05
[Ö|).)%]
Outer Boundary
Inner Boundary
0.05
Profile “ASME Y14.5” -vs- “ISO 1101”
© IIGDT – Presentation at NACMA – October 8-9, 2012
Precision GD&T – Uniform Boundary
[Ö|).!][Ö|).!][Ö|).!][Ö|).!]0.1
50
25
“Profile Tolerancing Controls Simple and Complex Geometries”
13© IIGDT – Presentation at NACMA – October 8-9, 2012
Unless Otherwise Specified All Dimensions Controlled by the CAD Model and are Basic
Simultaneous Requirement (Planar Datums)
AC
B
[Ö|).(|A|B|C] [Ö|::).(|A|B|C]
Potential Problem with Datum’s B & C
14© IIGDT – Presentation at NACMA – October 8-9, 2012
Simultaneous Requirement (Planar Datums)
AC
B
[Ö|).(|A|B|C] [Ö|::).(|A|B|C]
Derived Boundaries
15© IIGDT – Presentation at NACMA – October 8-9, 2012
Nominal Geometry
Actual Geometry
Nominal Geometry
Tolerance Zone Tolerance Zone
Actual Geometry
Simultaneous Requirement (Planar Datums)
Designers intent simply requires all features to simultaneously lie within their respective
tolerancing zones in relationship to respective datum reference frame.
This allows all features to expand or contract in size and/or be out of square to Datum A
and/or be off location to datum B & C as long as they simultaneously lie within their
respective tolerance zone.
16© IIGDT – Presentation at NACMA – October 8-9, 2012
Nominal GeometryNominal Geometry
Tolerance Zone Tolerance Zone
Actual Geometry Actual Geometry
C
B B
A
Problem: Negative Effects of Datum B & C (if part truly does
not mate up against datum feature B & C) as part would be
required to shift and mate up against B & C respectively.
The resulting effect would be the part would lie outside the
respective Profile Boundaries
Simultaneous Requirement (Planar Datums)
17© IIGDT – Presentation at NACMA – October 8-9, 2012
Unless Otherwise Specified All Dimensions Controlled by the CAD Model and are Basic
Nominal GeometryNominal Geometry
Tolerance Zone Tolerance Zone
Actual Geometry Actual Geometry
C
B B
A
Simultaneous Requirement (Planar Datums)
Resulting Effects of Datum B & C would be that
part would require to be shifted to mate up with B
& C respectively and would result in the part lying
outside Profile Boundaries and be Rejected.
18© IIGDT – Presentation at NACMA – October 8-9, 2012
Unless Otherwise Specified All Dimensions Controlled by the CAD Model and are Basic
Simultaneous Requirement (Mid-Plane Analysis)
A
[Ö|).(|A|B|C] [Ö|::).(|A|B|C]B
C
Potential Problem with Datum’s B & C
19© IIGDT – Presentation at NACMA – October 8-9, 2012
A
[Ö|).(|A|B|C] [Ö|::).(|A|B|C]B
C
Datum B and Datum C are the mid-planes between their respective features
B
C
Simultaneous Requirement (Mid-Plane Analysis)
20© IIGDT – Presentation at NACMA – October 8-9, 2012
A
[Ö|).(|A|B|C] [Ö|::).(|A|B|C]B
C
B
C
Simultaneous Requirement (Mid-Plane Analysis)
Derived Boundaries
21© IIGDT – Presentation at NACMA – October 8-9, 2012
Nominal GeometryNominal Geometry
Tolerance Zone Tolerance Zone
Actual GeometryActual Geometry
Simultaneous Requirement (Mid-Plane Analysis)
Designers intent simply requires all features to simultaneously lie within their respective
tolerancing zones in relationship to respective datum reference frame.
This allows all features to expand or contract in size and/or be out of square to Datum A
and/or be off location to datum B & C as long as they simultaneously lie within their
respective tolerance zone.
22© IIGDT – Presentation at NACMA – October 8-9, 2012
Nominal GeometryNominal Geometry
Tolerance Zone Tolerance Zone
A
Actual GeometryActual Geometry
Simultaneous Requirement (Mid-Plane Analysis)
Designers intent simply requires all features to simultaneously lie within their
respective tolerancing zones in relationship to respective datum reference frame.
This allows all features to expand or contract in size and/or be out of square to Datum
A and/or be off location to datum B & C as long as they simultaneously lie within their
respective tolerance zone.
23© IIGDT – Presentation at NACMA – October 8-9, 2012
Nominal GeometryNominal Geometry
Tolerance Zone Tolerance Zone
AProblem: Without the part being constrained to datums B & C the part lies
within its respective tolerance zones. Negative Effects of Datum B & C
would be that it would force the part to shift and potentially lie outside the
respective Profile Boundaries
Actual GeometryActual Geometry
B
C
Simultaneous Requirement (Mid-Plane Analysis)
24© IIGDT – Presentation at NACMA – October 8-9, 2012
Nominal GeometryNominal Geometry
Tolerance Zone Tolerance Zone
A
Actual GeometryActual Geometry
B
C
Simultaneous Requirement (Mid-Plane Analysis)
Resulting Effects of Datum B & C would be that part would require to be
shifted to mate up with B & C respectively and would result in the part
lying outside Profile Boundaries and be Rejected.
25© IIGDT – Presentation at NACMA – October 8-9, 2012
Unless Otherwise Specified All Dimensions Controlled by the CAD Model and are Basic
Simultaneous Requirement
A
[Ö|).(|A] [Ö|::).(|A]
Simultaneous requirements come into play when “geometric
controls use the same datums, in the same order of precedence,
with the same datum feature modifiers.” All callouts under the
simultaneous requirement must be evaluated at the same time.
26© IIGDT – Presentation at NACMA – October 8-9, 2012
Simultaneous Requirement
A
[Ö|).(|A] [Ö|::).(|A]
Derived Boundaries
27© IIGDT – Presentation at NACMA – October 8-9, 2012
Simultaneous Requirement
Nominal GeometryNominal Geometry
Tolerance Zone Tolerance Zone
Actual GeometryActual Geometry
A
Designers intent simply requires all features to simultaneously lie
within their respective tolerancing zones.
This allows all features to expand or contract in size and/or be out
of square to Datum A and/or be off location to each other as long
as they simultaneously lie within their respective tolerance zone.
© IIGDT – Presentation at NACMA – October 8-9, 2012
Radii with “Un-Located” Center
This tolerance… …yields this boundary
R 2 ==== 0.2 Max R 2.2
Min R 1.8
Paragraph 2.15.1 of ASME Y14.5M-1994 States: Radius Tolerance
“A radius symbol R creates a zone defined by two arcs (the minimum and
maximum radii). The part surface must lie within this zone.”
Zero tolerance
Zero tolerance
© IIGDT – Presentation at NACMA – October 8-9, 2012
Radius with “Located” Center
Paragraph 1.8.2.1 of ASME Y14.5M-1994 States: Center of Radius
“Where a dimension is given to the center of a radius, a small cross is drawn at
the center. Extension lines and dimension lines are used to locate the center
© IIGDT – Presentation at NACMA – October 8-9, 2012
Specifying small arc radii for size using linear tolerancing and location using position tolerancing is a less than
optimum way of specifying design requirements as they do not represent the designers true intent which is simply
to have all the surface geometries lie within a uniform boundary which can only be done using Profile. In addition,
they are major problems with the analytical methods which in each case have large sensitivities and have
negative impacts for proving compliance with specification requirements and provide less than adequate feedback
to manufacturing to use for process optimization. The following shows analysis of a dataset that would reject the
part for size and position. The same dataset is used on the next page for analysis using profile.
© IIGDT – Presentation at NACMA – October 8-9, 2012
The same part from the previous page was
re-defined using profile and the same
dataset was used for analysis using a
minimum zone fit which proves all the
measured points comfortably lie within the
desired tolerance zone.
© IIGDT – Presentation at NACMA – October 8-9, 2012
Minimum Zone Fit is proper fit for Proof of
compliance but is difficult for manufacturing
to use to determine process optimization
Least Squares Fit (Best Fit) is “NOT” the proper fit
for proof of compliance but in many cases provides
fabulous graphical feedback to manufacturing to
use for process optimization
© IIGDT – Presentation at NACMA – October 8-9, 2012
Minimum Zone Fit is proper fit for Proof of
compliance but is difficult for manufacturing
to use to determine process optimization
Least Squares Fit (Best Fit) is “NOT” the proper fit
for proof of compliance but in many cases provides
fabulous graphical feedback to manufacturing to
use for process optimization
© IIGDT – Presentation at NACMA – October 8-9, 2012
[Ö|).!%:]green surfaces
[Ö|).@:]blue surfaces
[Ö|).#:]gray surfaces
Drawing Note: Unless Otherwise Specified All
Dimensions Are Basic and Controlled By The CAD
Model and Controlled Simultaneously
The above engineering drawing example depicts profile tolerancing of all 3D
surfaces being fully defined with three explicit profile of a surface callouts per
the ASME Y14.41-2003 Standard.
3D Profile Definition using ASME Y14.41-2003
© IIGDT – Presentation at NACMA – October 8-9, 2012
[Ö|).!%:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::]green surfaces
[Ö|).@::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::]blue surfaces
[0.104 (-0.041 / +0.052) 52%]
[0.066 (-0.033 / +0.019) 44%]
[Ö|).#::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::][0.156 (-0.066 / +0.078) 52%]
gray surfaces
[Ö|).!%:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::]green surfaces
[Ö|).@::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::]blue surfaces
[0.104 (-0.041 / +0.052) 52%]
[0.066 (-0.033 / +0.019) 44%]
[Ö|).#::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::][0.156 (-0.066 / +0.078) 52%]
gray surfacesDrawing Note: Unless Otherwise
Specified All Dimensions Are Basic and
Controlled By The CAD Model
[Ö|).!%:]green surfaces
[Ö|).@:]blue surfaces
[Ö|).#:]gray surfaces
Drawing Note: Unless Otherwise
Specified All Dimensions Are Basic and
Controlled By The CAD Model
[Ö|).!%:]green surfaces
[Ö|).@:]blue surfaces
[Ö|).#:]gray surfaces
Unless Otherwise Specified All
Dimensions Are Basic and Controlled by
the CAD Model and Controlled
Simultaneously
Drawing Note: Unless Otherwise
Specified All Dimensions Are Basic and
Controlled By The CAD Model
[Ö|).!%:]green surfaces
[Ö|).@:]blue surfaces
[Ö|).#:]gray surfaces
Drawing Note: Unless Otherwise
Specified All Dimensions Are Basic and
Controlled By The CAD Model
[Ö|).!%:]green surfaces
[Ö|).@:]blue surfaces
[Ö|).#:]gray surfaces
Unless Otherwise Specified All
Dimensions Are Basic and Controlled by
the CAD Model and Controlled
Simultaneously
3D Analysis of all Surfaces Simultaneously
© IIGDT – Presentation at NACMA – October 8-9, 2012
“Quality Transformation”1. Turn engineering efforts into a science and eliminate redundant and
inefficient development initiatives
2. Gain a thorough understanding of the constraints & implications to critical
functional characteristics
3. Utilize this core knowledge to optimize leading-edge processes which meet or
exceed market needs and use to your advantage to determine and optimize the
vital few development needs
(Applies To: Product, Tooling, Equipment, Design, Process and Measurement)
“Find the waste… Get rid of it… Keep it gone…
Do it right the first time”
Foundation for Effective Foundation for Effective
CommunicationCommunication
© IIGDT – Presentation at NACMA – October 8-9, 2012
GD&T Applies to all DisciplinesCustomers
Supplier Technicians
Supplier Engineers
Receiving Inspectors
Rec. Inspection Techs.
Measurement Engineers
Suppliers
Purchasing
Machine Operators
Process Technicians
Process Engineers
Measurement Technicians
Measurement Engineers
Quality-Technicians
Quality-Engineers
Inspectors
Drafters
Designers
Engineers
Machine Operators
Machinists
Tool Makers
Exec. Level
Manufacturing Quality/Measurement Design Tool RoomAdministration
Engineers
Sales/Applications
Sales
Executives
© IIGDT – Presentation at NACMA – October 8-9, 2012
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