Tolerances Training
Contents•Introduction•Fits•Tolerancing•Tolerances•Modifiers
Tolerances Training
Guide to GD&T– Variants Still AllowedGuide to GD&T– Variants Still Allowed
GEOMETRIC DIMENSIONING & TOLERANCING
ANSI Y14.5M – R1988 STANDARD
History:•Since 1900•Widely used during WW2•Automotive Industry •Standardisation 1982
Tolerances Training
Engg. Intent – Dimension &ToleranceEngg. Intent – Dimension &Tolerance
GD&T
•Define the GEOMETRY of the part precisely
•Communicate the product Function & Design Relationship
•Process Variation
Whys?
Tolerances Training Dimensioning
• Defines the SIZE of a feature
• Defines the LOCATION of a feature
Dimension
Basic Size Size Limit
Function defines Tolerance, Tolerance defines Process
Tolerances Training
Hole Based System Hole Based System
Fits
Transition Fit Interference Fit
Shaft
Hole Zero Line
•Press – For Non Fe – Allows removal•Drive - For Fe Medium , Non Fe Light – Allows removal•Force/Shrink – High Interference
H6/p5 , H7/p6 H6/r5 , H7/r6 , H6/s5 , H7 / s6H6/u5 , H7/u6
•Clearance – Very Small Clearance•True - Zero Clearance , Slight Interference tolerated•Interference – Slight Interference
H6/h5 , H6/h6 H7/h6 ,H7/h7H8/h7 , H8/h8H9/h8 , H9 / h9H11/h9 , H11/h11H8/b9 , H8/a9
H6/j5 , H7/j6 , H8 /j7H6/k5 , H7/k6 , H6/k7H6 /m5 ,H7/m6 , H8/m7
H6/g5 , H7/g6 H6/f65 , H7/f7 , H7/e7 , H8 / e8H8/d8 , H8/d9
Location & Assembly Fit
ShaftHole Zero Line
Hole Zero LineShaft
ShaftShaft
Running & Sliding Fit
Shaft
Hole Zero Line
•Stationary parts•Location – Precision / Close /Normal/Loose•Assembly – Slack / Positional Fit
•Precision – Small Clearance - Location• Close Running - Shafts• Normal Running – Large Shafts , Brgs•Loose Running – Medium clearance Pulleys,PBs•Slack/Positional – Large Clearance - Not used
Tolerances Training Tolerancing
Bilateral Tolerances : •20 +/-0.018
•20 +0.013 / - 0.015
Unilateral tolerances :•20 +0.018 /0
•20 –0.012/-0.016
Tolerances Training
Tolerance stack – Proper dimensioning keyTolerance stack – Proper dimensioning key
Tolerance Stack up
15+/-0.2 10+/-0.2 10+/-0.28+/-0.2
28+/-0.6
43+/-0.2
33+/-0.2
15+/-0.2
25+/-0.2
28+/-0.4
Chain Method:• Point to Point• Shifting reference•Cumulative effect on tolerance
Base Line Method:• Single Reference • Reduced cumulative effect on tolerance
Direct Method:(Combination)• Direct Reference • Least cumulative effect on tolerance
33+/-0.2
15+/-0.2
25+/-0.2
28+/-0.4
Tolerances Training
Function defines Tolerance, Tolerance defines ProcessFunction defines Tolerance, Tolerance defines Process
TolerancesTolerances
FormForm •Limits deviation of an individual parameter from it geometrically ideal form
ProfileProfile •Same as Form
PositionPosition •Limits the deviation of the relative position of two or more parameters
ProcessProcess •Limits the deviation of a “ Fundamental”parameter ( Like Temp, Pressure Time
Tolerances Training
5 Types5 Types
Types
Form
Straightness
Flatness
Circularity
Cylindricity
ProfileProfile of a Line
Profile of a Surface
PositionOrientation
Location
Angularity
Perpendicularity
Parallelism
True Position
Concentricity
SymmetryRun OutCircular Run - Out
Total Run - out
Tolerances Training
Always look at the mating partAlways look at the mating part
Modifiers
“Modifiers” •Modify the specified tolerance •Influence the tolerance zone•Defined by the function
M
L
RFS
Common Modifiers
MMC - Maximum Material Condition
LMC – Least Material Condition
S Regardless of Feature Size
Reference
S
SR
R Radius
Spherical Radius
Spherical Diameter
Tolerances Training Notations
Toleranced Element/Parameter
0.02 A
Tolerance Symbol
Tolerance Symbol
Datum ( When required)
A
Reference Datum
Datum Symbol
25 Nominal Dimension
Axis as Datum Surface Line as Datum
Tolerances Training Feature Control Frame
Position Tolerance Zone Symbol
BA0.2 M CM
Shape of Tolerance Zone
Size of Tolerance Zone Primary Datum
Secondary Datum
Tertiary Datum
Material Condition ModifierSecondary Datum
Material Condition Modifier
Tolerances Training
Function drives Modifiers Function drives Modifiers
Modifiers
E=mC2
E=cM2
Tolerances Training
Tolerance Zone does not ChangeTolerance Zone does not Change
Modifiers
RFS – Regardless of Feature Size•The tolerance value is unaltered “Regardless of Size” of toleranced parts
Application•Holes with Zero Clearance•Shaft /Hole combination for Interference fits
Tolerances Training
Process Control Size Vs PositionProcess Control Size Vs Position
LMC
LMC – Least Material Condition - SIZE conditions•The Feature of size : It has the Least Material within the size limits specified
Rules:• External Features – Subtract the tolerance •Internal Features – Add the tolerance
25
20
12 +0.2 / - 0.1
BA0.2 CL
C
B
A
Actual LMC Position Applied11.9 12.2 0.2 -0.1
12 12.2 0.2 012.1 12.2 0.2 0.112.2 12.2 0.2 0.2
ToleranceSize
Tolerances Training
Process Control Size Boss Vs HoleProcess Control Size Boss Vs Hole
LMC
25 +2
BA1 CL
BA0.2 CL
LMC – Boss & Hole
C
B
12 - 0.5
A75
60
25
12
Boss Tol. Zone 1
Hole Tol. Zone 0.2
Tolerances Training
Bonus ZoneBonus Zone
Modifiers
MMC – Maximum Material Condition - SIZE conditions•The Feature of size : It has the Maximum Material within the size limits specified
Rules:• External Features – Add the tolerance •Internal Features – Subtract the tolerance
Application•Clearance holes ( Mounting/Assembly)
Eg; Position Tolerance of the hole increase as the hole size increases
Tolerances Training
Classic Case- Bell Crank & SleeveClassic Case- Bell Crank & Sleeve
Modifiers at MMC
A
A0.02 M
25
0.0
0/-0
.018
18
0.0
0 /-
0.0
13
A
A0.02 M
25
0 .0
2/0
.00
18
0.0
13/0
.00
FeatureShaft Dia1
Shaft Dia2
Pos Tol of SD1
Delta of SD2 Allowable
At MMC 25 18 0.02 0 0.02At LMC 24.982 0.02 0.018 0.038At Inter 24.99 0.02 0.01 0.03
FeatureBore Dia1
Bore Dia2
Pos Tol BD1
Delta of BD2 Allowable
At MMC 25 18 0.02 0 0.02At LMC 25.02 0.02 0.02 0.04At Inter 25.01 0.02 0.01 0.03
Tolerances Training Modifiers MMC On HoleM
Datum
A0.2 M
Hole
60
10 +0.2 / 0
20 +0.1 / 0
A
0.4
Actual MMC Position Allowable10.2 10 0.1 0.2
Size Tolerance
Tolerances Training Modifiers at MMC On Datum M
Datum Hole
A0.2 M
60
10 +0.2 / 0
20 +0.1 / 0
A
0.3
Actual MMC Position Allowable20.1 20 0.1 0.15
Size Tolerance
Tolerances Training Modifiers MMC On Hole & Datum M
Datum
0.2 M
Hole
60
10 +0.2 / 0
20 +0.1 / 0
A
A M
0.6
Actual Datum
MMC Datum
Actual Hole MMC Hole Position Allowable
20.1 20 10.2 10 0.1 0.3
Size Size Tolerance
Tolerances Training
Datum Ref. Frame is Theoretical Datum Ref. Frame is Theoretical
Datum
•Origin from which a Location of a feature is defined
• Origin from which the shape of a feature is defined
• Theoretical “Perfect geometry” ( Point , Line or Plane)
Tolerances Training
Manufacturing & Inspection w.r.t.specified datum Manufacturing & Inspection w.r.t.specified datum
Datum
A
AExternal Datum
A
Datum Simulator
Datum Simulator
Datum Simulator
Internal Datum
Tolerances Training
Controls Form of Cylindrical/Conical Surfaces- Applies to Entire SurfaceControls Form of Cylindrical/Conical Surfaces- Applies to Entire Surface
DEFINITION : Straightness is a condition where the surface or an axis of an element is a straight line.
TOLERANCE ZONE : Straightness tolerance•Specifies a tolerance zone within which the considered surface/axis or derived median line must lie. •Straightness tolerance is applied in the view where the parameter to be controlled is represented by a straight line.
REFERENCE TO DATUMS : No reference datum.
MMC, LMC, RFS TO FEATURE : Applicable if the tolerance applies to the axis or center plane of a feature or size. Not applicable if the toleranced feature is a surface.
MMC, LMC, RFS TO DATUMS : No datum reference
.
PERFECT FORM AT MMC : Applicable when the tolerance is applied to a surface. "Perfect from at MMC not required" may be specified.
Especially useful when the part is subject to small deformations under its own weight or internal stresses.
STRAIGHTNESS 0.21
Tolerances Training
Straightness: Applied to the Surface Cylinder
•The surface must lie within the specified tolerance zone•The dimension of perfect form at MMC (1.510).•Each longitudinal element must lie within two parallel lines 0.002 apart.
STRAIGHTNESS 0.21
Tolerances Training
Neck
Bow
Barrel
STRAIGHTNESS 0.21
Tolerances Training
Cylinder Liner Tier 2Cylinder Liner Tier 2
STRAIGHTNESS 0.21
Tolerances Training
Note effect of Size Tolerance Note effect of Size Tolerance
Straightness tolerance is• Applied in the view where the elements to be controlled are represented by a straight line.• Tolerance zone is constrained into the plane of projection of the view where it is called.•For each linear element on the surface, the tolerance zone of straightness may be
oriented differently, as long as it stays in the correct plane.
STRAIGHTNESS 0.21
Tolerances Training
Direction is in the ViewDirection is in the View
Straightness: Applied to a plane surfaceMeasurement Direction
STRAIGHTNESS 0.21
Tolerances Training
Combined Straightness “is” FlatnessCombined Straightness “is” Flatness
The tol. notation is attached to a leader line to the surface or to an extension line of the surface.
STRAIGHTNESS 0.21
Tolerances Training
Controls Form deviation of plane surfaces – Qualifies surface for primary datumControls Form deviation of plane surfaces – Qualifies surface for primary datum
FLATNESS
DEFINITION Flatness is the condition of a surface having all the elements of which in one plane.
TOLERANCE ZONE The flatness tolerance specifies a tolerance zone defined by two parallel planes within which the surface must lie.
REFERENCE TO DATUMS No reference datum.
MMC, LMC, RFS TO FEATURE
Not applicable.
MMC, LMC, RFS TO DATUMS Not applicable.No reference datum
PERFECT FORM AT MMC Where the surface under consideration has a size dimension, the flatness tolerance must be less than the size tolerance.
Flatness 0.05
0.05/100
Tolerances Training
•The surface must lie between two parallel planes 0.25 apart.•The surface must be within the specified limits of size.
Flatness 0.05
Tolerances Training
Flatness – Primary Datum/Seat/Sealing faceFlatness – Primary Datum/Seat/Sealing face
Flatness 0.05
Tolerances Training
Datum , Seat DefinitionDatum , Seat Definition
Flatness 0.05
Tolerances Training
Defines DatumDefines Datum
DEFINITION Circularity is a condition of a surface of revolution where a. (For a Cylindrical/Round feature other than a sphere,) all points of the surface intersected by any plane perpendicular to the axis are equidistant from that axis; b. For a sphere, all points of the surface intersected by any plane passing through a common center are equidistant from that center.
TOLERANCE ZONE A circularity tolerance specifies a tolerance zone bounded by two concentric circles within which each circular element of the surface must lie, and applies independently at any plane.
REFERENCE TO DATUMS
No reference datum.
MMC, LMC, RFS TO FEATURE
Not applicable.
MMC, LMC, RFS TO DATUMS
Not applicable.No reference datum
PERFECT FORM AT MMC The circularity tolerance must be less than the size tolerance, except for parts subject to free state variation.
CIRCULARITY/ROUNDNESS 0.05
Tolerances Training
The tolerance zone of circularity is expressed as the radial difference between two concentric circles
The circularity tolerance applies at each circular section of the diameter independently
CIRCULARITY/ROUNDNESS 0.05
Tolerances Training CIRCULARITY/ROUNDNESS 0.05
Tolerances Training
“Combined effect” of Straightness & Roundness“Combined effect” of Straightness & Roundness
DEFINITION Cylindricity is a condition of a surface of revolution in which all points of the surface are equidistant from a common axis.
TOLERANCE ZONE A Cylindricity tolerance specifies a tolerance zone bounded by two concentric cylinders within which the surface must lie.
REFERENCE TO DATUMS
No reference datum.
MMC, LMC, RFS TO FEATURE
Not applicable.
MMC, LMC, RFS TO DATUMS
Not applicable.No reference datum
PERFECT FORM AT MMC
Applicable. Cylindricity tolerances cannot violate the maximum boundary of perfect form at MMC of the associated size tolerance.
Application Functional applications that require a true cylinder such as rotating shaft journal and bearing diameters, pistons and piston bores. Also used to qualify datum diameters. Used only when the size tolerance does not provide appropriate form control.
Cylindricity 0.03
Tolerances Training
•The tolerance zone of Cylindricity is made of two concentric cylinders. •The leader line from the tol. notation may be shown in either view.
Cylindricity 0.03
Tolerances Training Cylindricity 0.03
Tolerances Training
DEFINITION A profile is the outline of an object in a given plane. The profile tolerance specifies a uniform boundary along the true profile within which the elements of the line must lie. It is used to control form or combinations of size, form, orientation, and location.
TOLERANCE ZONE The tolerance zone established by the profile of a line tolerance is two-dimensional, extending along the length of the considered feature. This applies to the profiles of parts having a varying cross section, such as the tapered wing of an aircraft, or to random cross sections of parts where it is not desired to control the entire surface of the feature as a single entity.
REFERENCE TO DATUMS
In most cases, profile of line tolerance requires reference to datum in order to provide proper orientation, location, or both, of the profile. With profile of a line tolerance, datum may be used under some circumstances but would not be used when the only requirement is the profile shape taken cross section by cross section. An example is the shape of a continuous extrusion.
MMC, LMC, RFS TO FEATURE
The specified tolerance can only apply on an RFS basis.
MMC, LMC, RFS TO DATUMS
The datum reference can only apply on an RFS basis.
Application Typically used to control profiles of parts having a varying cross section.
Line Profile 0.1
0.1 A
Tolerances Training
Effect of SizeEffect of Size
Form Tolerance Line Profile
Each line element of the surface between points C and D, at any cross section, must•Lie between two profile boundaries 0.16 apart in relation to datum planes A and B.•Be within the specified limits of size.
Tolerances Training
DEFINITION A profile is the outline of an object in a given plane. The profile tolerance specifies a uniform boundary along the true profile within witch the elements of the line must lie. It is used to control form or combinations of size, form, orientation, and location.
TOLERANCE ZONE The tolerance zone established by the profile of a surface tolerance is three-dimensional, extending along the length and width (or circumference) of the considered feature or features.
REFERENCE TO DATUMS
Profile of surface tolerance requires reference to datum in order to provide proper orientation, location, or both, of the profile. With profile of a line tolerance, datum may be used in some circumstances but would not be used when the only requirement is the profile shape.
MMC, LMC, RFS TO FEATURE
The specified tolerance can only apply on an RFS basis.
MMC, LMC, RFS TO DATUMS
The datum reference can only apply on an RFS basis.
TYPICAL USE Typically used to control parts with a surface of revolution, or castings with surfaces defined by profile tolerances .
Surface Profile 0.05
A0.05
Tolerances Training
Note Effect of Size ToleranceNote Effect of Size Tolerance
The surface between points D and E must •Lie between two profile boundaries 0.25 apart.•Perpendicular to datum plane A, •Equally disposed about the true profile and positioned with respect to datum planes B and C.
Surface Profile 0.05
Tolerances Training
Gen 1 Bell Crank Gen 1 Bell Crank
Surface Profile 0.05
Tolerances Training
•Each surface must lie between two common parallel planes 0.08 apart.•Both surfaces must be within the specified limits of size.
Surface Profile 0.05
Tolerances Training
Position Tolerance
Tolerances Training
DEFINITION Defines a zone within which the•Center• Axis•Center plane of feature of size is permitted to vary from a true (theoretically exact) position
TOLERANCE ZONE A position tolerance specifies one of the following: 1. A tolerance zone defined by two parallel planes related to specified datum.2. A cylindrical tolerance zone related to specified datum, within which the axis of the considered
feature must lie.3. A spherical tolerance zone related to specified datum, within which the center of the considered
feature must lie.
REFERENCE TO DATUMS
Obligatory with the PLTZF. Optional with the FRTZF.
MMC, LMC, RFS TO FEATURE
Based functional requirements MMC, LMC or RFS, appropriate modifier can be applied on position tolerance.
MMC, LMC, RFS TO DATUMS
Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on the datum axis. Application of MMC, LMC and RFS is limited to features subject to variations in size.
Hole Position 0.2
Tolerances Training
ZERO POSITIONAL TOLERANCE AT MMC
Where no variations in position is allowed at the MMC limit of size, the feature control frame contains a zero for the tolerance zone size, modified by the MMC symbol.
PATTERN-LOCATING TOLERANCE ZONE FRAMEWORK (PLTZF)
Where composite controls are used, the upper segment is referred to as the pattern-locating control. The PLTZF is located from specified datum by basic dimensions. It specifies the larger positional tolerance for the location of the pattern of features as a group.
FEATURE-RELATING TOLERANCE ZONE FRAMEWORK (FRTZF)
The lower segment is referred to as the features-locating control. It governs the smaller positional tolerance for each feature within the pattern (feature-to-feature relationship). Where datum references are not specified in the lower segment of the composite feature control frame, the FRTZF is free to bee located and oriented within the boundaries established and governed by the PLTZF. If datum are specified in the lower segment, they govern the orientation of the FRTZF relative to the PLTZF.
TYPICAL USE Typically used to control the location of features in assembly.
BA0.2 CM
BA0.2 CM BA0.2 CMM
0.2 M
Hole Position 0.2
Tolerances Training
The PLTZF (Ø0.8) is located from datum (ABC) by basic dimensions. It specifies the larger positional tolerance for the location of the pattern of holes as a group.The lower segment governs the smaller positional tolerance (Ø0.25) (feature-to-feature relationship) within the pattern .The FRTZF is free to locate and orient within the boundaries established and governed by the PLTZF.Datum A governs the orientation (perpendicularity) of the FRTZF.
Pattern Location - PLTZF
Feature Realtion - FRTZF
Hole Position 0.2
Tolerances Training
Co- Axial Holes
Pattern Location - PLTZF
Feature Relation Location - FRTZF
Hole Position 0.2
Tolerances Training
Gen 1 Bell CrankGen 1 Bell Crank
•C-D Defines X-Axis
Hole Position 0.2
•E Defines Y-Axis •B Defines Perpendicularity
Tolerances Training Hole Position 0.2
Tolerances Training
DEFINITION The median points of all diametrically opposed elements of a surface of revolution lie on the same axis (or center point) of a datum feature.
TOLERANCE ZONE A concentricity tolerance is aCylindrical (or spherical) tolerance zone whose axis (or center point) coincides with the axis (or center point) of the datum feature(s).
REFERENCE TO DATUMS
One datum feature (axis or center point).
APPLICABILITY OF MMC, LMC, RFS TO FEATURE
The specified tolerance can only apply on an RFS basis.
APPLICABILITY OF MMC, LMC, RFS TO DATUMS
The datum reference can only apply on an RFS basis.
TYPICAL USE Typically used to control ………..
Concentricity 0.04 A
Tolerances Training Position Tolerance Concentricity
Regardless of feature size, ( within size tolerance)•All median points of diametrically opposed elements of the slot must lie within Ø0.4 cylindrical tolerance zone.•The axis of the tolerance zone coincides with the axis of datum feature A.
Tolerances Training
Use Either as DatumUse Either as Datum
Position Tolerance Concentricity
Tolerances Training
Use a Spigot Locator Use a Spigot Locator
Position Tolerance Concentricity
Tolerances Training
DEFINITION The median points of all opposed or correspondingly-located elements of two or more feature surface lie in the same axis or center plane of a datum feature.
TOLERANCE ZONE
A symmetry tolerance is two parallel planes whose axis (or center plane) coincides with the axis (or center plane) of the datum feature.
REFERENCE TO DATUMS
One datum feature (center plane).
APPLICABILITY OF MMC, LMC, RFS TO FEATURE
The specified tolerance can only apply on an RFS basis.
APPLICABILITY OF MMC, LMC, RFS TO DATUMS
The datum reference can only apply on an RFS basis.
Symmetry 0.05 A
Tolerances Training
Regardless of feature size,( within Size Tolerance) all median points of opposed elements of the slot must •Lie between two parallel planes 0.8 apart.•The two parallel planes being equally disposed about datum plane A
Symmetry 0.05 A
Tolerances Training
Gen1 Bell CrankGen1 Bell Crank
Symmetry 0.05 A
Tolerances Training Position Tolerance Angularity
DEFINITION Condition of a surface, center plane, or axis at a specified angle from a datum plane or axis.
TOLERANCE ZONE A angularity tolerance specifies one of the following: 1. A tolerance zone defined by two parallel planes at the specified basic angle from one or more datum planes or axis, within which the surface or center plane of the considered feature must lie.2. A tolerance zone defined by two parallel planes at the specified basic angle from one or more datum planes or axis, within which the axis ot the considered feature must lie.3. A cylindrical tolerance zone at the specified basic angle from one or more datum planes or axis, within which the axis of the considered feature must lie.4. A tolerance zone defined by two parallel lines at the specified basic angle from one or more datum planes or axis, within which the line element of the surface must lie.
REFERENCE TO DATUMS
One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction.
MMC, LMC, RFS TO FEATURE
Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on angularity tolerance. Application of MMC, LMC and RFS is limited to features subject to variations in size.
MMC, LMC, RFS TO DATUMS
If the functional requirements of some applications require MMC, LMC or RFS, appropriate modifier can be applied on the datum axis. Application of MMC, LMC and RFS is limited to features subject to variations in size.
PERFECT ANGULARITY AT MMC
Where no variations of angularity at MMC size limit of feature, the feature control frame contains a zero for the tolerance, modified by the symbol for MMC.
TYPICAL USE Typically used to control orientation between planes surfaces.
Tolerances Training Position Tolerance Angularity
Regardless of feature size,the feature axis must •Lie within a 0.2 diameter cylindrical zone inclined 60º to datum plane A.•Be within the specified tolerance of location.
Angularity : Applied to Cylindrical Feature
Tolerances Training Position Tolerance Angularity
The surface must •Lie between two parallel planes 0.4 mm apart which are inclined at 30º to datum A.•Be within the specified limits of size.
Angularity : Applied to Plane Surface
Tolerances Training Position Tolerance PerpendicularityDEFINITION Condition of a surface, center plane, or axis at a right angle to a datum plane or axis.
TOLERANCE ZONE 1. A tolerance zone defined by tow parallel planes perpendicular to a datum plane or axis, within which the surface or center plane of the considered feature must lie.2. A tolerance zone defined by two parallel planes perpendicular to a datum axis, within which the axis ot the considered feature must lie.3. A cylindrical tolerance zone perpendicular to a datum plane, within which the axis of the considered feature must lie.4. A tolerance zone defined by two parallel lines perpendicular to a datum plane or axis, within which the line element of the surface must lie.
REFERENCE TO DATUMS
One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction.
MMC, LMC, RFS TO FEATURE
Based on the functional requirement MMC, LMC or RFS, appropriate modifier can be applied on perpendicularity tolerance. Application of MMC, LMC and RFS is limited to features subject to variations in size.
MMC, LMC, RFS TO DATUMS
Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on the datum axis. Application of MMC, LMC and RFS is limited to features subject to variations in size..
PERFECT PEPENDICULARITY AT MMC
Where no variations of perpendicularity at MMC size limit of feature, the feature control frame contains a zero for the tolerance, modified by the symbol for MMC.
Tolerances Training Perpendicularity
•The surface must lie between two parallel planes 0.12 mm apart which are perpendicular to datum plane. •The surface must be within the specified limits of size.
Perpendicularity : Applied to Plane Surface
Tolerances Training
Perpendicularity : Applied to Cylindrical Feature
Regardless of feature size,( within Size Tolerance limits the feature axis must •Lie within a 0.2 mm diameter cylindrical zone perpendicular to datum axis A. •Be within the specified tolerance of location.
Perpendicularity
Tolerances Training
Tolerances Training10
0
Tolerances Training Position Tolerance Parallelism
DEFINITION Condition of a surface, center plane, equidistant at all points from a datum plane; or axis and equidistant along its length from one or more datum planes or a datum axis.
TOLERANCE ZONE A parallelism tolerance specifies one of the following: 1. A tolerance zone defined by tow parallel planes parallel to a datum plane or axis, within which the surface or center plane of the considered feature must lie.2. A tolerance zone defined by two parallel planes parallel to a datum axis, within which the axis ot the considered feature must lie.3. A cylindrical tolerance zone parallel to a datum plane, within which the axis of the considered feature must lie.4. A tolerance zone defined by two parallel lines parallel to a datum plane or axis, within which the line element of the surface must lie.
REFERENCE TO DATUMS
One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction.
MMC, LMC, RFS TO FEATURE
Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on parallelism tolerance. Application of MMC, LMC and RFS is limited to features subject to variations in size.
MMC, LMC, RFS TO DATUMS
Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on the datum axis. Application of MMC, LMC and RFS is limited to features subject to variations in size..
PERFECT PARALLELISM AT MMC
Where no variations of parallelism at MMC size limit of feature, the feature control frame contains a zero for the tolerance, modified by the symbol for MMC.
Tolerances Training Position Tolerance Parallelism
The surface must •Lie between two parallel planes 0.12 mm apart which are parallel to datum plane.•Be within the specified limits of size
Parallelism : Applied to Plane Surface
Tolerances Training Position Tolerance Parallelism
Tolerances Training
Parallelism : Applied to Cylindrical Feature
Regardless of feature size,the feature axis must •Lie within a 0.2 mm diameter cylindrical zone parallel to datum axis A.•Be within the specified tolerance of location.
Position Tolerance Parallelism
Tolerances Training Position Tolerance Run-out
DEFINITION Runout is a composite tolerance used to control the functional relationship of one or more features of a part to a datum axis. The types of features controlled by runout tolerance include those surfaces constructed around a datum axis and those constructed at right angles to a datum axis.
TOLERANCE ZONE Each considered feature must be within its runout tolerance when the part is rotated about the datum axis. The tolerance specified for a controlled surface is the total tolerance or full indicator movement (FIM).
REFERENCE TO DATUMS
One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction.
APPLICABILITY OF MMC, LMC, RFS TO FEATURE
The specified tolerance can only apply on an RFS basis.
APPLICABILITY OF MMC, LMC, RFS TO DATUMS
The specified datum can only apply on an RFS basis.
TYPICAL USE Typically used to control circularity and concentricity simultaneously.
Tolerances Training Position Tolerance Run-out
Run-Out: Circular / Radial Run- Out
At any measuring position, each circular element of these surfaces must be within the specified run-out tolerance (0.02 mm FIM) when the part is rotated 360º about the datum axis with the indicator fixed in a position normal to the true geometric shape.
Tolerances Training
Run-Out: (Circular / Radial) Total Indicated Reading
The entire surface must lie with the specified total run-out tolerance zone (0.02 mm FIM) When the part is rotated 360º about the datum axis with the indicator placed at every location along the surface in a position normal to the true geometric shape without reset of the indicator
Tolerances Training
Run-Out: (Circular / Radial) Total Indicated Reading
Tolerances Training
Run-Out: Face- Total Indicated Reading- Example
Tolerances Training
Tolerances Training
Building Blocks
Tolerances Training
TemplateTemplate
Types
Straightness
Flatness
Circularity
Cylindricity
Profile of a Line
Profile of a Surface
Angularity
Perpendicularity
Parallelism
Concentricity
True Position
Symmetry
Circular Run - Out
Total Run - out
25 +2
BA1 CL BA0.2 CL
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