Download - 08.Flatness Straightness

7/22/2019 08.Flatness Straightness

1/35

ALEX P.M.

0206

FLATNESSMEASUREMENT


2/35

FLATNESS ?


3/35

Flatness measurement :jackscrewmethod

Part is mounted on

jackscrews

Jackscrews are preleveled

using a height gage.


4/35

jackscrewmethod :

Part surface has been leveledto the surface plate.

Comparing the surface tothe optimum plane. (FIM)


5/35

Flatness measurement : wobble - platemethod

Leveling Wobble plate in use.


6/35

Flatness measurement : fixed - planemethod

Part resting on threeequal pins. FIM being obtained from

the inverted surface.


7/35

Flatness measurement : direct - contactmethod


8/35

Direct - contact method

Mastering the probewith a precisionparallel

Inspecting the part.


9/35

Optical flatness inspection

Viewing the bands on the surface of the part with a

optical flat.


10/35

Optical flatness inspection

Contact method

Wedge method


11/35

Interpreting the Bands for Flatness Error

Straight, parallel &equally spaced bandsshows that the surface

is flat.

One band of error equals11.57 millionths out offlatness.


12/35


Concave : out of

flat by 2 bands.

Spherical concave : out of

flat by 2 bands


13/35


Spherical convex : outof flat by 2 bands(23.14 millionths).

Peaks & valleys : outof flat by 5 bands(57.85 millionths).


14/35

MEASUREMENT

STRAIGHTNESS

ALEX P.M.0206


15/35

STRAIGHTNESS ?


16/35

STRAIGHTNESS MEASUREMENT


17/35

Axis Vs surface element straightness


18/35

Straightness of surface element :cylindrical parts

f f


19/35

Straightness of surface element :jackscrew method

Establishing zero on the

part surface at one end.

Jackscrews are preleveled

using a height gage.


20/35

Straightness of surface element :jackscrew method

The indicator istraversed alongthe surfaceelements of theshaft (at the top

dead center) forstraightness errormeasurement

St i ht f f l t


21/35

Straightness of surface element :Precision straightedge method

A precision straightedge can be usedwhen tolerances are relatively loose.

St i ht f f l t


22/35

Straightness of surface element :Comparator method


23/35

Straightness of surface element :Two - Block method

The part is placed on top of

two equal height blocks.

Dial indicator indicates line

elements of the surface.


24/35

Straightness of surface element :

Noncylindrical parts

Jack screw method

Precision straightedge method

Conical parts

Optical comparator method Precision straightedge method

Wobble plate method

St i ht f i


25/35

Straightness of an axis :


26/35

Straightness of an axis :Differential measurement methods

Exploring a line element of the shaft.


27/35

Straightness of an axis :Differential measurement methods


28/35

Straightness of an axis :Precision spindle method


29/35


Example of a graph for

axial straightness error.

Polar graph showing that

the part is acceptable.


30/35


(A) Bowed shaft (B) Eccentric


31/35


(C) Out of round (D) Hourglass condition


32/35

Straightness of a centerplane :


33/35

Straightness of centerplane :Differential measurement methods

Indicating line elements of the part on the surface plate.


34/35

Some possible outcomes of centerplane straightness measurement


35/35

THANK U