Thursday 28 September 2017

(2)-Basic GD&T (Interview Questions)

Q1- How will you define GD&T?
Ans- GD&T is Geometric Dimensioning and Tolerancing.
Methods of showing tolerences using symbols.
it is engineering communication tool using symbols.
GD&T ensures repeatability and interchangeability.

Q2-How will you classify GD&T According to geometry?
Ans- There are five classes according to function of the geometry-
1-Form of geometry-
A- Flatness      B- Straightness   C- Cylindercity   D- Circularity

2- Orientation of geometry-
A-Parallelism     B- Perpendicularity    C- Angularity

3-Profile of geometry-
A-Profile of a line          B-Profile of a surface

4- Control of run out-
A- circular runout          B- Total Runout

5-Location of geometry-
A-Position           B- Symmetry    C-Concentricity

Q3- Differentiate b/w Flatness and straightness?
Ans- When cylindrical geometry of shaft subjected to twist or bend,it looses it's straightness. in below setup when dial indicator moved along the shaft, it will show whether the straightness is within tolerance or has deviated. the shaft is not revolving while measurement.

and flatness is straightness of plane profile at each and every point on the surface.

Q4- Differentiate b/w circularity and cylindercity?
Ans- Circularity is about roundness of tapered, concave or convex profile at particular section cylindercity of constant diameter cykunder along the length.
the dial indicator attached to a fixture with high precision revolves along the round profile to examine the roundness. in cylendercity it moves alongthe length while revolving to measure the roundness.

Q5- What do you mean by Reference Dimension?
Ans-     Symbol for Reference Dimension   (XX)
XX- Value of Dimension.    Ex- (40)
Reference dimension usually without tolerence, used for information purposes only. it does not givern production or inspection operations.