Orientation Controls Applied to Features of Size (DML/DMP)

•Parallelism•Perpendicularity•Angularity•Intro to Composite Controls

Orientation Tolerancing for Features of Size (DML/DMP)

– An orientation control is applied to a FOS by attaching the control frame to the size dimension of the feature in the Drawing Callout *

– The tolerance zone can be two parallel planes or a 3-D cylinder around the established axis of the feature

– In certain cases MMC, LMC conditions and VC can be applied

– Inspection is accomplished with:• Dial Indicators or CMM devices• Gauging - (With MMC modifier) much like straightness

applied to a FOS except that a datum is referenced

Parallelism

• Often used to Align Holes in Parallel *• True Position Can also Control Parallelism *

*

• Control Frame is attached to the Feature’s size dimension *

Parallelism Tolerance Applied to an Internal Cylinder

– The tolerance zone is defined by two parallel planes parallel to a datum plane

– The axis of the controlled feature must lie within the two parallel planes for the length of the feature *

No Diameter SymbolNo MMC Modifier *

Parallelism Tolerance Applied to an External Cylinder

– The tolerance zone is defined by two parallel planes parallel to a datum plane

– The axis of the controlled feature must lie within the two parallel planes for the length of the feature

No Diameter SymbolNo MMC Modifier

Parallelism Tolerance Applied to an Internal Cylinder– Notice the ø Symbol

which creates a cylindrical zone *

– Notice the MMC Modifier

*VC Internal Feature = Size of Feature at MMC –GTOL Value

Inspection Gage

Diameter Symbol andMMC Modifier*

Perpendicularity

Perpendicularity Applied to a Rectangular Feature of Size

• The perpendicularity of the cut is being controlled referenced to Datum A

• The Control Frame is Attached to the Feature’s Size Dimension

• There is no Diameter Symbol in the Control Frame

• There is a MMC Modifier in the Control Frame

• Is not controlling Location• True Position can Control Location and Perpendicularity

Perpendicularity Applied to a Rectangular Feature of Size

• The Tolerance Zone is Two Parallel Planes 0.1 Apart.

• The Feature’s Center Plane Must Lie Between the Two Parallel Planes.

• Functional Gauging, VC can be Used with Bonus Tolerance

0.1

Perpendicularity Applied to a Cylinder Feature of Size

–Very Common *–Notice the ø symbol in the control frame–The tolerance zone is a cylinder around the axis perpendicular to a datum plane–The axis of the controlled feature must lie within cylinder for the length of the feature

Internal Feature External Feature

Perpendicularity Applied to a Cylinder Feature of Size

–The cylindrical tolerance zone controls perpendicularity of the feature in all directions

Perpendicularity Applied to a Cylinder Feature of Size

– Inspection gages for the features–It’s like inspecting for straightness except it’

(VC)*

(VC)**

* VC Internal Feature = Size of Feature at MMC – GTOL Value

** VC External Feature = Size of Feature at MMC + GTOL Value

Internal Feature

External Feature

Perpendicularity Applied to a Cylinder Feature of Size With Bonus Tolerance

Bonus * Tolerance

Size Range

MMC Modifier *

Perpendicularity Applied to a Cylinder (RFS)

Size Range

Constant Tolerance

Value

No Functional

Gage

No MMC Modifier *

*

Perpendicularity (MMC) with a Maximum Tolerance Specified

Composite Controls – Perpendicularity used as a Refinement

Composite Control

Angularity

• Also is controlling Perpendicularity with Datum B

• It is rare to use MMC and Gaging for Angularity to FOS

• Often Inspected with CMM

Angularity Tolerance Applied to an Internal Cylinder FOS no Diameter Symbol

– The tolerance zone is defined by two parallel planes (Notice no Diameter Symbol) at the specified basic angle from a datum plane or axis

– The Angular Dimension is displayed as a Basic Dimension– The axis of the controlled feature must lie within the planes

for the length of the feature

Zone for Angularity Applied to a Rectangular Feature of Size (FOS)

What Would the Drawing Callout Look Like?