Metrology define calibration dating
In general, there will be errors of size in any machined work piece.This means that the actual dimension will be different from nominal dimension.The reading on the screen gives the dimension of the part. A coordinate measurement machine (CMM) is an advanced, multi-purpose quality control system used to help inspection keep pace with modern production requirements.It replaces long, complex and inefficient conventional inspection methods with simple procedures.CMM can check the dimensional and geometric accuracy of everything from small engine blocks, to sheet metal parts, to circuit boards.When the manufactured parts are big, with higher material cost and longer cycle times, on-process measurement is required to improve the productivity and reduce the cost.In the on-process measurement, parts are measured while they are on the machine tool.
Their surfaces are lapped and are flat and parallel within a range of 1-5 micro inch.
For the gauging process, the probe is moved towards the work piece and deflected by the contact.
The coordinate value of the point of the touch makes it possible to determine the work piece radius provided the position of the axis of rotation is known.
These errors should be within certain given limits by tolerances and determined by the dimensional measurement to guarantee the product quality.
The dimensional measurement includes: Traditionally, measurements have been made after the part has been produced. The post-process measurement can be used to high production run of smaller parts.