# Metrology 101

Articles on basic and applied metrology concepts. Enhance your knowledge or refresh your skills with our popular "Metrology 101" materials.

### How to Align a Crankshaft on a CMM

Crankshafts for internal combustion engines can be a bit tricky to align on a coordinate measuring machine because they are mostly a series of cylinders. The technique described below shows how to align a crankshaft for CMM inspection on a machine such as a Global Advantage.

### How to Check CMM Touch Probe Accuracy

How do you know if the tool you’re using is working properly? With a tool like a hammer it’s easy: if the nail goes in, then it’s working! But what about a high tech tool like a CMM probe? It is the complex device you put on the business end of your CMM, with many internal components that you can’t see which may be damaged, worn or out of adjustment. Where to start? Well, let’s start by thinking of it as a hammer and keep it simple.

### Intro to Coordinate Metrology

We use a coordinate system to describe the movements of a measuring machine. The coordinate system, invented by the famous French philosopher and mathematician René Descartes in the early 1600s, lets us locate features relative to other features on workpieces.

### Measuring in Artificial Atmospheric Pressure Environments

The speed of light is 186,000 miles per second in a vacuum. Fortunately, we don’t live in a vacuum. However, temperature and air pressure (atmospheric pressure) have a direct effect on the density of air and consequently the speed of light. Change in the speed of light, or “index of refraction,” is a value that must be considered for precision measurements with a laser tracker system.

### Metrology Automation is Here and Now

Even if you do not see or use these robots on a daily basis, they are working behind the scenes nonetheless. They helped to build the car you drive, the phone constantly within your reach, and the computer you depend on. It would nearly be impossible to go a full day and not come in contact with something created using these great machines.

### Portable Arm CMM Buyers Guide

The portable arm CMM (PCMM) has become an important quality control tool at many manufacturing companies. With the flexibility to be used nearly anywhere on a manufacturing floor, from in-process checks to large scale assembly to inside machine tools, measuring arms have the capability to deliver real-time dimensional feedback right at the point of production.

### Reverse Engineering

Reverse engineering is a method of creating a 3D virtual model from an existing physical part for use in 3D computer-aided design (CAD), computer-aided manufacturing (CAM), computer-aided engineering (CAE), or other software. The process involves measuring an object and then reconstructing it as a 3D model.

### ROMER Arm with Laser Scanner: Will it Scan?

Will it Scan or won't it? The ROMER Absolute Arm with Integrated Scanner is put though it's paces with a variety of typical, and some not so typical parts for laser scanning. The ROMER Absolute arm is a portable CMM. It is used in manufacturing and assembly operations to perform a variety of inspection, reverse engineering, alignment and precision 3D joining tasks.

### Should You Scan It?

Industrial metrology professionals are constantly tasked with finding the best methodology to inspect parts. When researching coordinate measuring machines (CMMs), or evaluating the capabilities of existing equipment, the discussion naturally turns toward accessories which will complement the CMM. Several solutions exist – each with its associated benefits and drawbacks. The trick is finding the correct option that is neither overkill nor inadequate.

### Temperature Compensation for Portable Metrology

Adjusting for the effects of ambient temperature when using portable metrology: To Comp or not to Comp? Changes in ambient temperature and the temperature of the parts we are measuring have an observable effect on many common industrial materials like steel and aluminum. It is for this very reason that for the most accurate measurements with large automated CMMs such as Globals and PMM's, a temperature controlled room, and even part temperature sensors are essential for the best results.

### The Difference Between Calibration and Certification

Two of the most often confused terms among users of metrology equipment are "Certification" and "Calibration". Not knowing the difference can cause headaches when it comes time to have your equipment's yearly....wait...do I need a certification or a calibration? As many have discovered, the terms are not interchangeable, even though they are often used interchangeably.

### The Importance of CMM Maintenance

Find out some easy things you can do to keep your CMM running in top condition, with the training manager from Hexagon Manufacturing Intelligence Service department. . Also discussed, HexagonMetrologyU , our new online e-learning portal.

### The Origins of the Articulated Arm CMM

Where did the Articulated Measuring Arm Come From?

### To Scan or Not to Scan?

Just because we can use high density scanning such as analog scanning, 3D laser scanning and chromatic white light to inspect and measure a part with point cloud data, should we? This panel discussion explores that question using some actual customer parts in this segment called "To Scan or Not to Scan?"

### What is a CMM Stylus?

A stylus (plural: styli) is the “tip” attached to a probe on a coordinate measuring machine, whether a traditional CMM machine or a portable measuring arm which makes physical contact with the component to be measured.

### Whitepaper: Modern CMM Design Concepts

Coordinate Measuring Machines (CMMs) are used in practically every industry that requires precise dimensional inspection of manufactured parts. In today's competitive environment, manufacturers demand CMMs that are accurate, reliable, fast, economical, and provide maximum flexibility with respect to operating environment.

### About ISO 10360 Standards for CMMs

These short explanations refer to the coordinate measuring machine (CMM) performance specifications referred to in product technical documentation. It is important to understand which version of the ISO specification any product documentation refers to, as there have been revisions to the specifications over time, and the terminology used within and testing procedures have changed.