Dimensional metrology
Encyclopedia
Dimensional Metrology is the science of calibrating and using physical measurement equipment to quantify the physical size of or distance from any given object. Inspection is a critical step in product development and quality control
. Dimensional Metrology requires the use of a variety of physical scales to determine dimension, with the most accurate of these being holographic etalons or laser interferometers. The realization of dimension using these accurate scale technologies is the end goal of dimensional metrologists.
Early metrologist
s would often create a central measurement standard based on a yard stick or meter. For example, early Egyptian meter sticks where based on a piece of metal that was the size of the Pharaoh's forearm called a Cubit
. Carpenters were some of the first dimensional inspectors as seen today.
Modern measurement equipment include hand tools, CMMs (Coordinate-Measurement Machine), machine vision systems, laser trackers, and optical comparators. For hand tools, see Caliper
and micrometer
. A CMM is based on CNC technology to automate measurement of Cartesian coordinates using a touch probe, contact scanning probe, or non-contact sensor. Optical comparators are used when physically touching the part is undesirable. Optical comparators can now build 3D models of a scanned part and internal passages using x-ray technology.
Furthermore, optical 3d (laser) scanners are becoming more and common. By using a light sensitive detector (e.g. digital camera) and a light source (laser, line projector) the triangulation principle is employed to generate 3d data, which is evaluated in order to compare the measures against nominal geometries.
Data is collected in or compared to a print. A print is a blueprint illustrating crucial features. Prints can be hand drawn or automatically generated by a CAD model.
Industrial Metrology for manufacturing quality and for Standards room/calibration activities are called as first principle method of deriving the actual value of measurement. the field of in process gauging, incycle gauging and post process gauging are excluded from this topic
Equipments generally used for manufacturing quality depends on industry, but broadly around mechanical engineering and in particular automotive aerospace, machine tool, any other precision parts suitable for instrumentation. This is broadly listed below:
1. Basic hand held instruments like Vernier Caliper, digital caliper, micrometer etc.
Quality control
Quality control, or QC for short, is a process by which entities review the quality of all factors involved in production. This approach places an emphasis on three aspects:...
. Dimensional Metrology requires the use of a variety of physical scales to determine dimension, with the most accurate of these being holographic etalons or laser interferometers. The realization of dimension using these accurate scale technologies is the end goal of dimensional metrologists.
Early metrologist
Metrologist
Metrologists perform metrology work involving precision measurement and comparison of physical quantities such as mass, length, time, force, speed, voltage and current. They calibrate precision equipment which measures these physical units. They may also certify that outside standards of such...
s would often create a central measurement standard based on a yard stick or meter. For example, early Egyptian meter sticks where based on a piece of metal that was the size of the Pharaoh's forearm called a Cubit
Cubit
The cubit is a traditional unit of length, based on the length of the forearm. Cubits of various lengths were employed in many parts of the world in Antiquity, in the Middle Ages and into Early Modern Times....
. Carpenters were some of the first dimensional inspectors as seen today.
Modern measurement equipment include hand tools, CMMs (Coordinate-Measurement Machine), machine vision systems, laser trackers, and optical comparators. For hand tools, see Caliper
Caliper
A caliper is a device used to measure the distance between two opposing sides of an object. A caliper can be as simple as a compass with inward or outward-facing points...
and micrometer
Micrometer
A micrometer , sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw used widely for precise measurement of small distances in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier,...
. A CMM is based on CNC technology to automate measurement of Cartesian coordinates using a touch probe, contact scanning probe, or non-contact sensor. Optical comparators are used when physically touching the part is undesirable. Optical comparators can now build 3D models of a scanned part and internal passages using x-ray technology.
Furthermore, optical 3d (laser) scanners are becoming more and common. By using a light sensitive detector (e.g. digital camera) and a light source (laser, line projector) the triangulation principle is employed to generate 3d data, which is evaluated in order to compare the measures against nominal geometries.
Data is collected in or compared to a print. A print is a blueprint illustrating crucial features. Prints can be hand drawn or automatically generated by a CAD model.
See also
- Mechanical EngineeringMechanical engineeringMechanical engineering is a discipline of engineering that applies the principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the...
Industrial Metrology for manufacturing quality and for Standards room/calibration activities are called as first principle method of deriving the actual value of measurement. the field of in process gauging, incycle gauging and post process gauging are excluded from this topic
Equipments generally used for manufacturing quality depends on industry, but broadly around mechanical engineering and in particular automotive aerospace, machine tool, any other precision parts suitable for instrumentation. This is broadly listed below:
1. Basic hand held instruments like Vernier Caliper, digital caliper, micrometer etc.