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In metrology and the fields that it serves (such as manufacturing, machining, and engineering), total indicator reading (TIR), also known by the newer name full indicator movement (FIM), is the difference between the maximum and minimum measurements, that is, readings of an indicator, on the planar, cylindrical, or contoured surface of a part ...
Absolute flatness is the flatness of an object when measured against an absolute scale, in which the reference flat (standard) is completely free of irregularities. The flatness of any optical flat is relative to the flatness of the original standard that was used to calibrate it. Therefore, because both surfaces have some irregularities, there ...
An ornate 18th century iron straightedge. A straightedge or straight edge is a tool used for drawing straight lines, or checking their straightness. If it has equally spaced markings along its length, it is usually called a ruler.
In manufacturing and mechanical engineering, flatness is an important geometric condition for workpieces and tools. Flatness is the condition of a surface or derived median plane having all elements in one plane. [1] Geometric dimensioning and tolerancing has provided geometrically defined, quantitative ways of defining flatness operationally.
(4) After eliminating the aberration On the axis, coma and astigmatism, the relation for the flatness of the field in the third order is expressed by the Petzval equation, S1/r(n'−n) = 0, where r is the radius of a refracting surface, n and n' the refractive indices of the neighboring media, and S the sign of summation for all refracting ...
Ideal test indicator pushed. Prior to modern geared dial mechanisms, test indicators using a single lever or systems of levers were common. The range and precision of these devices were generally inferior to modern dial type units, with a range of 10/1000 inch to 30/1000 inch, and precision of 1/1000 inch being typical.
Surface metrology is the measurement of small-scale features on surfaces, and is a branch of metrology.Surface primary form, surface fractality, and surface finish (including surface roughness) are the parameters most commonly associated with the field.
Critical dimensions as step, curvature, flatness are computed from the surface topography. While the historical notion of a profilometer was a device similar to a phonograph that measures a surface as the surface is moved relative to the contact profilometer's stylus , this notion is changing with the emergence of numerous non-contact ...