1. Dr. HABEEB HATTAB HABEEB Office: BN-Block, Level-3, Room-088
UNITEN
Dr. HABEEB HATTAB HABEEB
Office: BN-Block, Level-3, Room-088
Ext. No.: 7292
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

2. University TENAGA National
College Of Engineering Mechanical Department Academic Year –
Lecture Note
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

3. Computer Aided Manufacturing
CAM
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

4. Tolerances Cylindrical Fits & Geometric Tolerances
A Dimensioning Technique That Ensures the Interchangeability of Parts
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

5. ENGR 111
CLASS 13.2
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

6. Learning Objectives
Apply linear tolerances in both the English and Metric systems.
Calculate the following parameters, given a dimensioned set of mating parts: Allowance, Clearance, Hole Tolerance, Shaft Tolerance.
Match Geometric Tolerance symbols with their meaning.
Apply Geometric tolerances with AutoCAD.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

7. Tolerance ??? The Oxford English dictionary defines tolerance as:
- In Mech., an allowable amount of variation in the dimensions of a machine or part. More widely, the allowable amount of variation in any specified quantity
Or, paraphrased… “Tolerance is how accepting of errors you are”.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

8. General Concepts
A measurement with a zero tolerance is impossible to manufacture in the real world.
Tolerances on parts contribute to the expense of a part, the smaller the tolerance the more expensive the part.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

9. Types of Tolerances
General Tolerances –Limit the error a machinist is allowed on all dimensions, unless otherwise specified
Linear Tolerances –Specific error limits for a particular linear measurement.
Geometric Tolerances– Error limits, not on the size, but on the shape of a feature.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

10. General Tolerance . Are specified in the title block of a drawing.
Must always be included on “real” parts. .
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

11. Linear Tolerance
Is an overriding tolerance which specifies a tolerance for one specific dimension.
Can be listed in limit or deviation form, but normally should be specified on an engineering drawing in limit form.
Should only be used in the case of real necessity, not just because.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

12. Example of Linear Tolerance
The parts shown to the right illustrates a linear tolerance shown in limit form.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

13. “Forms” of Linear Tolerance
Unilateral.
Variation in
one direction
Bilateral.
two directions
Limit.
Max & Min..
largest on top
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

14. There are four parameters of interest:
Terminology:
There are four parameters of interest:
Hole Tolerance.
Shaft Tolerance.
Allowance.
Maximum Clearance.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

15. Determines the cost of manufacturing the hole.
Hole Tolerance
The difference between the diameters of the largest and smallest possible holes.
Determines the cost of manufacturing the hole.
Does not consider the Shaft at all.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

16. Determines the cost of the shaft. Does not consider the Hole at all.
Shaft Tolerance
The difference between the diameters of the largest and smallest possible shafts.
Determines the cost of the shaft.
Does not consider the Hole at all.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

17. The tightest fit between two mating parts.
Allowance
The tightest fit between two mating parts.
Determines how the two parts will interact with one another.
Smallest hole minus largest shaft.
Or the “gap” between smallest hole & largest shaft.
Does not affect the cost of the parts.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

18. The loosest fit between mating parts.
Maximum Clearance
The loosest fit between mating parts.
Determines how the two parts will interact with one another.
Largest hole minus smallest shaft.
Or the “gap” between largest hole & smallest shaft.
Does not affect the cost of the parts.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

19. Formulas for calculation
Hole Tolerance = LH - SH
Shaft Tolerance = LS - SS
Allowance = SH - LS
Maximum Clearance = LH - SS
LH=Large Hole, SH=Small Hole
LS-Large Shaft, SS=Small Shaft
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

20. Other definitions Nominal Size - The approximate size of a part.
Actual Size - The measured size of a finished part.
Basic Size - The exact theoretical size for a part, used to calculate the acceptable limits.
Hole Basis - A system of fits based on the minimum hole size as the basic diameter.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

21. Practical Application
This class is trying to teach provide the design basic aspect of tolerance
We will be interested in applying a given tolerance to a part, not in determining the “best” tolerance.
Various industries (aerospace, electronics, automotive, etc.) set their own tolerances.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

22. Types of Fits
Linear tolerances can be classified in 4 major categories, based on the interaction between the parts :
Clearance Fit.
Line Fit.
Transition Fit.
Interference Fit (Force Fit).
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

23. English Example Running and sliding fit RC9 Basic diameter 2.00”
Hole limits , 0
Shaft limits , -13.5
Max Clear ????
Allowance ????
Hole Tolerance. ????
Shaft Tolerance ????
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

24. English Example
Note that all values are listed in thousandths of an inch.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

25. English Example Running and sliding fit RC9 Basic diameter 2.00”
Hole limits , 0
Shaft limits , -13.5
Max Clear
Allowance
Hole Tolerance
Shaft Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

26. Clearance Fit
In a clearance fit, the two parts will always fit together with room to spare
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

27. Clearance Fit
In a clearance fit, the two parts will always fit together with room to spare
As a team, calculate the: Hole Tolerance.______ Shaft Tolerance.______ Allowance.__________ Clearance. __________ for the fit shown …
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

28. Clearance Fit
In a clearance fit, the two parts will always fit together with room to spare
As a team, calculate the: Hole Tolerance Shaft Tolerance Allowance Clearance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

29. Line Fit
In a line fit, the two parts may fit together with no room to spare
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

30. Line Fit
In a line fit, the two parts may fit together with no room to spare
As a team, calculate the: Hole Tolerance._____ Shaft Tolerance._____ Allowance. _________ Clearance. _________ for the fit shown ……
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

31. Line Fit
In a line fit, the two parts may fit together with no room to spare
As a team, calculate the: Hole Tolerance Shaft Tolerance Allowance Clearance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

32. Transition Fit
In a transition fit, the two parts may either clear or interfere with each other…probably the cheapest way to manufacture products. Used with selective assembly process
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

33. Transition Fit
In a transition fit, the two parts may either clear or interfere with each other
As a team, calculate the: Hole Tolerance._____ Shaft Tolerance._____ Allowance._________ Clearance.__________ for the fit shown to the right. …………….
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

34. Transition Fit
In a transition fit, the two parts may either clear or interfere with each other
As a team, calculate the: Hole Tolerance Shaft Tolerance Allowance Clearance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

35. Interference Fit
In an interference fit, the two parts will always interfere with each other, requiring a force or press fit
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

36. Interference Fit
In an interference fit, the two parts will always interfere with each other, requiring a force or press fit
As pairs, calculate the Hole Tolerance.________ Shaft Tolerance.________ Allowance.____________ Clearance._____________ for the fit shown to the right. ………………
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

37. Interference Fit
In an interference fit, the two parts will always interfere with each other, requiring a force or press fit
As pairs, calculate the Hole Tolerance Shaft Tolerance Allowance Clearance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

38. English Fits ANSI standards list five type of fits:
RC: Running and Sliding Clearance Fits
LC: Clearance Locational Fits
LT: Transition Locational Fits
LN: Interference Locational Fits
FN: Force and Shrink Fits
Each of these has several classes (Next slide)
The higher the class number, the greater the tolerance and the looser the fit.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

39. Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

40. Metric Fits Clearance Fits Transition Interference
H11/c11
Loose Running: For wide commercial tolerances on external members.
H9/d9
Free Running: For large temperature variations, high running speeds, or heavy journal pressures.
H8/f7
Close Running: For accurate location and moderate speeds and journal pressures.
H7/g6
Sliding: Fit not intended to run freely, but to turn and move freely, and to locate accurately.
H7/h6
Locational Clearance: Fit provides snug fit for locating stationary parts; but can be freely assembled and disassembled.
Transition
H7/k6
Locational Transition: Fit for accurate location, a compromise between clearance and interference.
H7/n6
Locational Transition: Fit for more accurate location where greater interference is permissible.
Interference
H7/p6
Locational Interference: Fit for parts requiring rigidity and alignment with prime accuracy of location, but without special bore pressure requirements.
H7/s6
Medium Drive: Fit for ordinary steel parts or shrink fits on light sections, the tightest fit usable with cast iron.
H7/u6
Force: Fit suitable for parts which can be highly stressed or for shrink fits where the heavy pressing forces required are impractical.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

41. Metric Example H11/c11 (loose running) Basic diameter 40 mm
Hole size ,40.000
Shaft size ,39.720
Max Clear ????
Allowance ????
Hole Tolerance ????
Shaft Tolerance ????
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

42. Metric Example H11/c11 (loose running) Basic diameter 40 mm
Hole size ,40.000
Shaft size ,39.720
Max Clear
Allowance
Hole Tolerance
Shaft Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

43. Geometric Tolerances
Geometric tolerancing is a system that specifies tolerances that control location form, profile, orientation, location, and runout on a dimensioned part.
NOTE:
Many standard symbols are
Used to represent “Geotol”
Relationships…parallel,
perpendicular, angular,
round, and flat are fairly obvious
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

44. Geometric Tolerances
Feature control boxes (call outs) are used to place geometric tolerances in most drawings. Standard letter height is recommended (1/8-in or 3 mm)
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

45. Geometric Tolerances L LMC….Least Mat’l Cond. M MMC...Max Mat’l Cond.
R RFS…..Regardless of Feature size.
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

46. Use of a Callout
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47. Use of a Datum and Callout
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48. Straightness Tolerance Zone Straightness Tolerance
TOLERANCES OF FORM
Straightness
Straightness Tolerance Zone
TOLERANCES OF FORM
Straightness
Definition: Straightness is the condition where one line element of a surface or axis is in a straight line. Tolerance: Straightness tolerance provides a zone in which a surface element or axis implied regardless of feature size.
Straightness Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

49. Flatness Tolerance Zone
TOLERANCES OF FORM
Flatness
Flatness
Definition: Flatness is the condition of a surface where all elements are in one plane. Tolerance: Flatness tolerance provides a zone of a specified thickness defined by two parallel planes in which the surface must lie. The specified tolerance in the feature control frame is implied as regardless of feature size (RFS).
Flatness Tolerance Zone
Flatness Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

50. Circularity Tolerance Zone Circularity Tolerance
TOLERANCES OF FORM
Circularity
Circularity
Definition: Circularity is roundness. Circularity is a condition of a cylindrical surface at any cross-sectional measurement where all points of the surface are perpendicular.
Tolerance: Circularity tolerance provides a circular zone in which all points of a cross section or slice of the surface must lie.
Circularity Tolerance Zone
Circularity Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

51. Cylindricity Tolerance Zone Cylindricity Tolerance
TOLERANCES OF FORM
Cylindricity Tolerance Zone
Cylindricity
Cylindricity
Definition: Cylindricity is the condition of an entire feature surface during one revolution in which all surface points are an equal distance from a common axis.
Tolerance: Cylindricity tolerance provides a zone bounded by two concentric cylinders in which the controlled surface must lie. Cylindricity tolerance is a radial tolerance.
Cylindricity Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

52. TOLERANCES OF ORIENTATION
Perpendicularity
Perpendicularity Tolerance Zone
TOLERANCES OF ORIENTATION
Perpendicularity
Definition: Perpendicularity is the condition of an entire surface plane or axis at a right angle to a datum plane or axis.
Tolerance: Perpendicularity tolerance provides a zone defined by two parallel planes, two parallel lines, or a cylinder parallel to a datum.
Perpendicularity Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

53. TOLERANCES OF ORIENTATION Angularity Tolerance Zone
Definition: Angularity is the condition of an axis or plane at an angle other than 90o to another datum plane or axis.
Tolerance: Angularity tolerance provides a zone defined by two parallel planes the stated tolerance apart and at the specified basic angle to the datum reference. The controlled feature surface, plane, or axis must lie within this zone.
Angularity Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

54. TOLERANCES OF ORIENTATION
Parallelism
Parallelism Tolerance Zone
Parallelism
Definition: Parallelism is the condition of a surface or axis an equal distance at all points from a datum plane or axis.
Tolerance: Parallelism tolerance provides a zone defined by two parallel planes, lines, or a cylinder parallel to a datum plane or axis within which the surface elements or axis of the controlled feature must lie.
Parallelism Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

55. Profile Tolerance Zone of Line Profile Tolerance of Line
TOLERANCE OF PROFILE
Profile
Profile Tolerance Zone of Line
TOLERANCE OF PROFILE
Profile
Definition: Profile tolerancing is a method of specifying control of deviation from the desired profile along the surface of a feature.
Tolerance: Profile tolerance may be specified either as a surface or line profile. The tolerance provides a uniform zone along a desired true profile of the part. The surface of controlled feature must lie within this zone.
Profile Tolerance of Line
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56. TOLERANCE OF PROFILE (Cont) Profile Tolerance of Surface
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57. Circular Runout Tolerance Zone
TOLERANCE OF RUNOUT
Runout
TOLERANCE OF RUNOUT
Definition: Runout is a composite form and location control of permissible error in the desired part surface during a complete revolution of the part around a datum axis.
Tolerance: Runout tolerance may be specified as either total or circular. The specified tolerance is the deviation permitted in relation to the controlled feature’s axis. The surface must lie within the specified tolerance zone.
Circular Runout Tolerance Zone
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

58. TOLERANCE OF RUNOUT (Cont) Total Runout Tolerance
Circular Runout Tolerance
Total Runout Tolerance
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59. Concentricity Tolerance Zone Concentricity Tolerance
TOLERANCE OF LOCATION
Concentricity
Concentricity Tolerance Zone
TOLERANCE OF LOCATION
Concentricity
Definition: Concentricity is the condition where the axes of all cross-sectional surface elements during one complete revolution are common to a datum feature axis within a specified tolerance.
Tolerance: Concentricity tolerance is always implied and specified as regardless of feature size. The tolerance is a diametrical zone in which the axis of the axis of the controlled feature must lie.
Concentricity Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

60. Position Tolerance Zone
TOLERANCE OF LOCATION
Position
Position Tolerance Zone
Position
Definition: Position is the condition where a feature or group of features is located (positioned) in relation to an other feature or datum feature.
Tolerance: Location tolerance zones are either cylindrical or noncylindrical; this is determined in the feature control frame. The tolerance zone is cylindrical if the diameter symbol precedes the specified tolerance.
Position Tolerance
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

61. Geometric Tolerances in ACAD
Geometric tolerances in AutoCAD are normally applied on the end of a leader.
After invoking the quick leader command, but BEFORE selecting any points, you can select settings to allow the placement of a callout box, rather than a note
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

62. Leader Settings Dialogue box
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63. Tolerance option
If you select the Tolerance option you will be presented with the following dialogue box rather than a text prompt
Lecturer: Dr. HABEEB ALANI University TENAGA Nasional

64. THANK YOU
Lecturer: Dr. HABEEB ALANI
University TENAGA Nasional