What is Metrology?

3D Metrology 

What is 3D metrology? Metrology is the science of measurement. It establishes a common understanding of units, crucial in linking and understanding human activities. When we apply metrology to the field of 3D this generally refers to measuring size, volume, and depth. When dealing with objects it is important to have precise measurements of their size for various reasons. You may need to do Quality Assurance to see if your product is as specified or may be looking for defects and anomalies. A very important part of 3D metrology is the ability to have measurement data that helps the production of manufacturable products.

3D metrology is typically conducted with the use of hand tools, CMM technology, machine vision systems, laser trackers, scanners, and optical comparators. CMM technology refers to coordinate measuring machines. A CMM is typically done with a touch probe, scanning contact probe, or non-contact sensor.  Machine vision (MV) is the technology and methods used to provide imaging-based automatic inspection and analysis for applications such as automatic inspection, process control, and robot guidance, usually in industry. Machine vision is a term encompassing a large number of technologies, software and hardware products, integrated systems, actions, methods and expertise. Machine vision as a systems engineering discipline can be considered distinct from computer vision, a form of computer science. Laser trackers are instruments that accurately measure large objects by determining the positions of optical targets held against those objects. The accuracy of laser trackers is of the order of 0.025 mm over a distance of several metres.  Some examples of laser tracker applications are to align aircraft wings during assembly and to align large machine tools. An optical comparator (often called just a comparator in context) or profile projector is a device that applies the principles of optics to the inspection of manufactured parts. In a comparator, the magnified silhouette of a part is projected upon the screen, and the dimensions and geometry of the part are measured against prescribed limits. It is a useful item in a small parts machine shop or production line for the quality control inspection team.

Faro Laser Tracker

Accuracy and precision are of utmost importance for the field of 3D metrology. Accurate data for 3D models leads to higher repeatability. This then leads towards a future of automation and scaling up of technology for the additive manufacturing world. This field is relevant outside of just the additive world. Classical manufacturing methods have been utilizing these tools for quite some time as well. It is important to understand these tools for any practitioner within the additive space. Classical methods and technology are still applicable. Metrology has been important for a while, and hence it will increase in its importance for the field of additive over time. Prototyping to production scale is the main area of concern. It allows for improvements to occur over time gradually in terms of product production. 

We will be taking a look a bit more into the field of metrology over the next couple of months. In particular we will be learning a little bit more about the technology behind metrology as well as organizations involved in this field. It is important to understand this field for additive manufacturing as the replicability of precise objects based on dimension is critical for product development. We will also be showcasing companies in particular that will be featured in the 3D metrology conference that will be occurring in London this November.