3. DATUM TARGETS SYMBOLS(contd….)

8. DATUM TARGETS SYMBOLS(contd….)

10. Creating a partial reference frame from offset surfaces(contd…)

11. Creating a partial datum reference frame from irregular surfaces

14. FORM CONTROLS

15. FORM CONTROLS FLATNESS STRAIGHTNESS CIRCULARITY CYLINDRICITY

17. FLATNESS c

18. FLATNESS Definition : Flatness is the condition of a surface having all of its elements in one plane. The tolerance zone for a flatness control is three-dimensional. General representation

23. 0.4 FLATNESS ERROR 0.4 FLATNESS ERROR MMC Part would have to be perfectly flat on both sides LMC Part could have 0.4 flatness error on both sides

26. UNIT FLATNESS

27. Indirect Flatness Controls There are several geometric controls that can indirectly affect the flatness of a surface; they are Rule #1, perpendicularity, parallelism, angularity, total runout and profile of a surface. When any of these controls are used on a surface, they also limit the flatness of the surface. However indirect form controls are not inspected . If it is desired to have the flatness of a surface inspected, a flatness control should be specified on the drawing. If a flatness control is specified its tolerance value must be less than the tolerance value of any indirect flatness controls that affect the surface.

28. Flatness When Inspecting Flatness, There Is No Datum.

29. In this example, flatness has been applied to datum feature A.

30. Three possible inspection methods are illustrated. In all cases, considered feature is isolated from rest of part and aligned relative to indicator. In the first case, the part is leveled on the surface plate. In the second illustration, the surface is leveled by placing it on three equal height gage blocks. The indicator is then moved across the surface. In the third illustration, the CMM will mathematically "level" the points of the surface contacted by the probe. In all cases the FIM (Full Indicator Movement) may not exceed 0.2mm.

31. Problem: If the surface is convex, the part will rock making it difficult to determine the minimum indicator reading over the entire surface. problem may cause an acceptable surface to be rejected.

32. Problem: Ideally, the gage blocks should be placed under the high points on the surface. Otherwise, the indicator movement may not be the lowest possible. problem may cause an acceptable surface to be rejected.

33. CMM will automatically align points to evaluate flatness error. Problem: Often insufficient points are taken to evaluate the flatness error. As a result, an out of spec surface may be accepted. Inspecting flatness requires time and patience.

34. Questions and Answers

38. 2. Describe how a flatness tolerance zone is located ________. By contacting three high points on the surface.

39. 3. On the drawing above, what is the maximum allowable flatness error of surface A ?

40. 3. On the drawing given, the maximum allowable flatness error of surface A is 0.4

41. 4. On the drawing above, what is the maximum allowable flatness error of surface B ?

42. 4. On the drawing given, the maximum allowable flatness error on surface B is 0.4

45. 6. What is the maximum permissible flatness error of surface A and surface B ?

46. 6. The maximum permissible flatness error of surface A is 0.1 and for surface B is 0.4

47. 7. Could the flatness control tolerance value be increased to 0.5 ?

48. 7. NO.

49. 8. If the 21.8 – 22.2 dimension was increased to 21.6 – 22.4 , would this change the flatness tolerance zone on surface A ?

50. 8. NO.

51. STRAIGHTNESS ‐

53. General Representation Axis Centre plane

54. Interpretation (Straightness applied to the surface element)

57. Verifying Straightness Applied to Surface Elements Establish the first line of the tolerance zone by placing the part surface on a surface plate.

58. Verifying Straightness Applied to Surface Elements The surface plate becomes the true counterpart. Using a gauge wire with a diameter equal to the straightness tolerance value, check the distance between the true counterpart and the low points of the line element of the part surface.

59. Verifying Straightness Applied to Surface Elements If the gauge wire will not fit between the part and the surface plate, the straightness error of the line element is less than the allowable value . If, at any point along the part, the wire does fit into the space between the part and surface plate, line element straightness is not within its specifications.

60. Interpretation (Straightness applied to the axis) 0.2 0.2mm

62. Rule #1's Effects on Straightness of a FOS Whenever Rule #1 applies to a FOS, an automatic straightness control exists for the axis

63. When the FOS is at MMC the axis (or centerplane) must be perfectly straight. As the FOS departs from MMC, a straightness error equal to the amount of the departure is allowed. Rule #1's Effects on Straightness of a FOS

68. Inspecting a Straightness Control (Applied to a FOS at MMC)

69. Questions and Answers

71. 1. The tolerance zone for straightness is two parallel lines stated tolerance apart .

72. 2. Describe the tolerance zone for the straightness callout.

73. 2. Two parallel lines at a distance of 0.05mm apart.

74. 3. If the straightness control was removed, what would control the straightness of the surface elements ?

75. 3. The dimensional limits of 0.4 (Rule #1)

78. 5. What limits the straightness of the diameter of the pin ?

79. 5. It is limited by the FOS dimension.

80. 6. Calculate the maximum amount of bonus tolerance possible, the maximum total allowable tolerance and the virtual condition.

81. 6. Maximum Bonus tolerance = 1.0 Total Allowable tolerance = 1.2 Virtual condition = 12.8

82. 7. Calculate the maximum amount of bonus tolerance possible, the maximum total allowable tolerance and the virtual condition.

83. 7. Maximum Bonus tolerance = 0.2 Total Allowable tolerance = 0.3 Virtual condition = 12.6

84. CIRCULARITY

85. Definition: Circularity is a condition where all points of a surface of revolution, at any Section perpendicular to a common axis, are equidistant from that axis. General representation: 0.2 39.0 38.5 CIRCULARITY

86. Example :

88. INTERPRETATION 0.2 94.2 – 94.6 0.2 79.4 – 79.8 0.2 Two imaginary and concentric circles with their radii 0.2mm apart. Part surface

89. What the designer wants. What the designer might get according to the print.

92. EFFECT OF RULE #1 ON CIRCULARITY Diameter equal to MMC Of feature of size 0.8 tolerance zone radial distance equal to the size tolerance of the diameter Circularity tolerance zone that results from Rule #1 is two coaxial circles The figure illustrates that the cross section elements must lie between two coaxial circles , one equal to the MMC of the diameter ,the second radially smaller by the size tolerance. Therefore a diametrical dimension automatically restricts the circularity to be equal to its size tolerance. 0.8

96. INSPECTION OF CIRCULARITY

97. Questions and Answers

98. 1. Describe the tolerance zone for a circularity control

99. Ans . Two perfectly concentric circles. ACTUAL SHAPE

100. 2. What controls the circularity of diameter A?

101. Ans . As per RULE#1.

102. 3. The maximum circularity error possible for diameter A is _______

103. Ans . 0.04

106. 5. For each circularity control shown below, indicate if it is a legal specification. If the control is illegal, explain why. ______________________ ___________________ ___________________ ___________________ Ø 0.2 O 0.2 S O 0.1 O 0.2 A O

107. Ans . For each circularity control shown below, indicate if it is a legal specification. If the control is illegal, explain why. -- NO,no modifiers. -- NO,diameter symbol not required . -- YES -- NO, circularity specification does not need a Datum Ø 0.2 O 0.2 S O 0.1 O 0.2 A O

108. CYLINDRICITY

109. Cylindricity Definition :Cylindricity is a condition of a surface of revolution in which all points of the surface are equidistant from a common axis. General Representation : g 0.2 39.0 38.5

110. Example & Interpretation:

113. EFFECT OF RULE #1 ON CYLINDRICITY The figure illustrates that the surface must lie between two coaxial cylinders, one equal to the MMC of the diameter ,the second radially smaller by the size tolerance. Therefore a diametrical dimension automatically restricts the cylindricity of a diameter to be equal to its size tolerance. 0.8

117. INSPECTION OF CYLINDRICITY

120. Questions and Answers

121. 1. Describe the tolerance zone for cylindricity.

122. Ans . Two perfectly concentric cylinders radially apart. ACTUAL SHAPE

123. 2. What controls the cylindricity of diameter A?

124. Ans . As per RULE#1.

125. 3. The maximum cylindricity error possible for diameter A is ?

126. Ans . 0.04 radially.

129. 5. For each cylindricity control shown below, indicate if it is a legal specification. If a control is illegal, explain why. ______________________ ____________________ ____________________ ___________________ g g g g 0.02 A 0.02 L 0.02 Ø 0.02

130. YES NO,diameter symbol not applicable NO, no modifiers applicable. No, no Datum required. g g g g Ans . For each cylindricity control shown below, indicate if it is a legal specification. If a control is illegal, explain why. 0.02 A 0.02 L 0.02 Ø 0.02

131. Tolerance of Position (TOP) Part-1

146. The Location of a Hole Controlled with Tolerance of Position (RFS)

148. The Location of a Pattern of Holes Controlled with Tolerance of Position (RFS)

150. The Location of Coaxial Diameters Controlled with Tolerance of Position (RFS)

156. The Location of a Hole Controlled with Tolerance of Position (RFS)

160. The Location of a Hole Pattern Controlled with Tolerance of Position (MMC)

162. Coaxial Diameter Applications

166. Tolerance Of Position,part-2

168. Bi-Directional TOP(Locating a Hole in two directions): In this application, the following conditions apply; -The tolerance zones are parallel boundaries in the direction of the TOP control. - The shape of tolerance zone is _________.

169. Bi-Directional TOP(Locating a Hole in Two Directions): In this application, the following conditions apply; -The tolerance zones are parallel boundaries in the direction of the TOP control. - The shape of tolerance zone is rectangular .

170. -The tolerance zones are located by the basic dimensions relative to the datum’s reference. -Bonus tolerances are permissible. Interpret the drawing and design a gauge pin? Bi-Directional TOP (Locating a Hole in Two Directions)

171. Bi-Directional TOP (Locating a Hole in Two Directions)

172. Using TOP to locate an elongated hole: In this application, the following conditions apply; -The tolerance zone shape is a boundary of identical shape as the elongated hole, minus the position tolerance value in each direction.

173. -There is no axis interpretation. -The tolerance zones are located by basic dimension relative to datum's referenced. Using TOP to locate an elongated hole

174. -Bonus tolerance are permissible. -The elongated hole must also meet its size requirements. Using TOP to locate an elongated hole (Contd..) Interpret the drawing and design a gauge pin?

175. Using TOP to locate an elongated hole (Contd..)

177. Note-2: If the same positional tolerance is desired in both directions, a single positional tolerance feature control frame may be used. In this instance, the feature control frame is directed to the elongated hole with a leader line. Using TOP to locate an elongated hole (Contd..)

180. Top Using a Projected Tolerance Zone (contd.)

181. Using TOP to Control Symmetrical Relationships In this application the following conditions apply: - The tolerance zone shape is two parallel planes.

182. -The tolerance zone is located by' an implied basic zero dimension relative to the datum referenced. - A bonus tolerance is permissible Using TOP to Control Symmetrical Relationships (contd.) Gauge for this component?

183. Using TOP to Control Symmetrical Relationships (contd.) The example shown, involves using TOP MMC, which controls a symmetrical relationship to ensure that the part can be assembled.

185. In this application, the following conditions apply: The shape of the tolerance zone is a cylindrical boundary' The dimension between the centerline of the diameter and the datum axis is an implied basic zero. TOP with the LMC Modifier (contd.)

186. A bonus tolerance is permissible. The minimum wall is l.6 (24.2-20.8 - 0.2) -:- 2 = 1.6]. Perfect form at LMC applies (perfect form at MMC is not required) TOP with the LMC Modifier (contd.)

188. In this figure, the TOP control limits the spacing between the holes and the square ness of the holes relative to datum plane A, but the TOP control does not control the location of the hole pattern Using TOP to Control Spacing and Orientation of a Pattern of Holes

190. When a hole pattern is used as a datum feature, it does not have to be located from outside edges of the part. The outside edges of the part can be defined from the hole pattern and toleranced with a profile control. Using TOP to Control Spacing and Orientation of a Pattern of Holes

191. Multiple single segment TOP controls A multiple single-segment TOP control is when two (or more) single segment TOP call outs are used to define the location, spacing, and orientation of a pattern of features of size.

193. Multiple single segment TOP controls (contd.) This type of control when a hole pattern can have a large tolerance with respect to the outside edges of the pan, but requires a tighter tolerance for square ness and/or spacing within the hole pattern.

194. TOP with zero tolerance at MMC. There are three primary benefits to ZT at MMC: 1. It provides flexibility for manufacturing. 2. It prevents the rejection of usable parts. 3. It reduces manufacturing costs. Zero Tolerance (ZT) at MMC is a method of tolerance part features that includes the geometric tolerance value with the FOS tolerance and states a zero tolerance at MMC in the feature control frame.

195. CONVENTIONAL POSITIONAL TOLERANCING AT MMC

196. ZERO POSITIONAL TOLERANCING AT MMC

197. SPHERICAL FEATURE LOCATED BY POSITIONAL TOLERANCING S

198. SPHERICAL FEATURE LOCATED BY POSITIONAL TOLERANCING

199. Position - Location of Irregular Feature Position can Control Location of Irregular Features

200. The figure shown below is a possible gage that might be used to inspect the position tolerance. The values shown are theoretical design values, which do not include gage tolerance and wear allowance.