profiles satya

7/28/2019 Profiles Satya

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NETTUR TECHNICAL TRAININGFOUNDATION

PROFILES Profile of a surface is considered as the

most powerful control in the geometrictolerance

It can be used to control the Size Location Orientation Form of a feature


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Symbols of profile Profile of a line

Profile of a surface


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Profile control applies to a profile control can be applied to a

true profile a profile control can be used to control

-size-location

-form


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Profile tolerance zone A profile control zone applies to the surface to

which the control is directed, unless extended byone of the three methods

the tolerance zone can be extended to cover additional surfaces by

Between symbol

All around symbol A note


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Advantages of a profile It provides a clear definition of the

tolerance zone

It communicates the datum sequence It eliminates accumulation of tolerances


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Profile of a surface

A profile of a surface control is a geometrictolerance that limits the amount of error asurface can have relative to its true profileapplications of profile control

-planar ,curved or irregular surfaces-polygons-cylinders ,surfaces of revolution or

cones-Coplanar surfaces


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Profile used to locate a surface location

Profile is applied to planar surfaces:Conditions : The profile callout is applied to a true

profile The true profile is related to the datums

referenced with basic dimensions The tolerance zone is a uniform boundary

centered around the true profile All elements of the surfaces must be within

the tolerance zone simultaneously


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The tolerance zone limits the location,orientation and form of the surface


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Profile used to tolerance polygon The profile callout is applied to a true

profile The true profile is related to the datums

referenced with basic dimensions The all around symbol extends the profile

tolerance zone to apply to all sides of the

polygon The tolerance zone is a uniform boundary

centered around the true profile


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Profile used to tolerance polygon All elements of the surface must be within

the tolerance zone The tolerance zone limits the

size,location,orientation and form of polygon

A max radius is used to limit the allowableradius on the corners of the polygon


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Profile tolerance used to conical feature The profile callout is appiled to a true profile.(the basic

angle establishes the true profile) The true profile is related to the datums referenced with

basic dimensions(an implied basic angle equal to half the specified angle exists)

The profile tolerance zone applies all around the cone. The tolerance zone is a uniform boundary centered

around the true profile.(the equal bilateral default is ineffect)

All elements of a surface must be within the profiletolerance zone The profile tolerance zone limits the orientation and form

of the conical surfaces


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Profile of a surface applied to a coplanar surface

When profile of a surface is applied tocoplanar surfaces,it controls the form of the surfaces as if they were a single

surface


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Profile used in multiple single-segment controls

A multiple single segment profilecontrol is where two or more profilecontrols are tolerancing a surface relativeto different datumsmultiple segment can be used to specify adifferent amount of tolerance for parameters of a surface .


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Inspecting profile of surface When inspecting profile of a surface,the

inspector measures points along thesurfaces to determine if the entire surfaceis in the tolerace zone


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PROFILE OF A LINE


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PROFILE OF A LINE

The basic concepts of profile of a surface and profile of a lineare similar.

The primary difference is that the tolerance zone for profile of asurface is three-dimensional, and the tolerance zone for profileof a line is two-dimensional.

A pro f i le of a l ine co nt ro l is a geometric tolerance thatlimits the amount of error for line elements relative to their trueprofile.

The tolerance zone is established in the same manner assurface profile.


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PROFILE OF A LINE The tolerance zone is two-dimensional; it is two uniform lines

applied at any cross section of the surface. Profile of a line provides a control in one direction only.

Therefore, profile of a line is often used as part of a multiplesingle-segment control for a surface.

It is common to use both a profile of a surface and a profile of aline control on the same surface. Another common method of applying profile of a line is as a refinement of a coordinatetolerance. Examples of these applications are shown later inthis section.

f l f d l d


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Profile of a Line Used to Control Form and Orientation in aMultiple Single-Segment Profile Control

Often, profile of a line is used to control the form and orientation of the line elements of a surface. Figure 12-14 shows an examplewhere profile of a surface controls the location as well as theorientation of the surface (in one direction). Profile of a line controlsthe orientation of the line elements (in one direction) and the form of the line elements. In Figure 12-14, the following conditions apply:

The profile callouts are applied to a true profile. The profile of a surface control limits the size, location, and

orientation relative to the datum's specified. The profile of a line control refines the form of the line elements. The profile of a line control refines the orientation of the line

elements in one direction. (Note that the profile of a line tolerancevalue is less than the profile of a surface tolerance value.)


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P fil f Li d C di T l U d C l


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Profile of a Line and a Coordinate Tolerance Used to ControlForm and Location

In this example, profile of a line is used with a coordinatetolerance. The coordinate tolerance locates the surface, and theprofile callout refines the form. The profile of a line control specifiestwo datum references; therefore, the profile of a line control affectsthe form and orientation of the line elements. Figure 12-15 shows anexample of profile of a line and a coordinate tolerance used tocontrol location, orientation, and form. In Figure 12-15, the followingconditions apply:

The profile callout is applied to & true profile. The coordinate tolerance locates the surface. The profile of a line control refines the form and orientation of the

line elements in one direction. (Note that the profile of a linetolerance value is less than the coordinate tolerance value.)


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Legal Specification Test for Profile of a Line

For a profile of a line control to be a legalspecification, if must satisfy the sameconditions as profile of a surface. Thelegal specification flowchart for profile inFigure 12-12 applies to both profile of asurface and profile of a line.


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Inspecting Profile of a Line In Figure 12-15, a profile of a line control is used as part of a

multiple control. The coordinate tolerance dimension would haveto be inspected to ensure the location of the true profile of thesurface. This would involve inspecting the height of the part. Nowlet's look at how to inspect the profile of a line control.

There are a number of ways the profile of a line control could beinspected. One way is to use a gage template as shown in Figure12-16, First, the template is placed on the surface line element.

Then, a gage pin with a diameter equal to the profile tolerancevalue is tried to check if it can be inserted into the gap betweenthe part surface and the gage template. If the gage pin fits intothe space between the gage template and part surface, the partsurface is out of the profile tolerance zone.

PART CALCULATIONS In industry, it is very common to make a calculation to find a max.

or min. distance on a part. When calculating a max. or min. partdistance, all of the part tolerances must be included. This sectionexplains how to use profile tolerances in part calculations .


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Tolerance stacks using profile Tolerance stacks on a part that uses profile (bilateral-equal

distribution) is straight forward. In this session, a simple

method of how to calculate the max. and min. distance apart is explained. Regarding thee steps below

1. label the start and end points of the distance to becalculated. On the start point of calculation draw a doubleended arrow. Label the arrow that points towards the end

point of the calculation as positive(+). Label the other arrowas negative(-)2. Establish a loop of part dimensions or gage distances fromthe start point to the end point of the calculation.

3. calculate the answer.

When solving for a min. distance, half the profile tolerancevalue ( for a bilateral-equal distribution control is subtractedfrom the calculation.

When solving for a max. distance, half the profile tolerancevalue is added to the calculation.


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