A Brief History Of CMM Technology

Posted by Tony Tillett on Apr 10, 2018 11:32:00 AM

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Coordinate Measurement Machines have an interesting history going back almost 60 years. The modern CMM industry produces over 6,000 new CMMs every year, as well as retrofitting and upgrading tens of thousands more. These CMMs can be Manual, where an operator guides the machine, CNC machines that are driven automatically by a special program. As ubiquitous as CMMs now are in manufacturing, it is hard to imagine a world when quality control was dependent on hand measurements.

The history of CMMs started in 1959 when they first appeared at the International Machine Tool Exhibition in Paris. They were manufactured by Ferranti, a British company that also developed the first commercial computer for a general audience in 1951.

Several big companies from the most developed countries of that time, including the USA, Japan, Germany, and France joined in the production of commercial CMMs during the 1960s. After this their use by businesses of all sizes quickly gathered pace.

Invention Of The Touch Probe

The co-founder of Renishaw, Sir David McMurtry, invented the Touch Trigger Probe in 1970, which enabled the Olympus engines used in Concorde aircrafts to pass specific requirements. This invention resulted in a revolution of 3D measurement, opening the world up to accurate and automatic measurements of separate components and entire assemblies.

3-Axis, 3D Systems

A classic CMM has an X, Y, and Z axis and operates in a 3D system. Every axis has a scale system that shows its position relative to other points. The CMM can read the touch probe input, as pre-set by software or by the operator. It uses discrete points to show the size and position with high precision.

With a touch probe, it's possible to generate automatic measuring points on the surface while recoding the XYZ position in space of the taken point. This device has changed the measurement process of parts and played a huge role in the globalisation of CMMs.

Renishaw changed the performance capabilities of CMMs once again in the early 1980s, when the motorised probe head was introduced. Further innovations included automatic probe changing racks, affordable scanning probes, and automatic probe stylus evolution.

Hardware Innovations Post 1980s

Even though CMM parts evolved dramatically between 1960 and 1988, the core technology behind coordinate measurement has been comparatively static for the last 30 years. Their mechanical structure has improved, making them lighter with better repeatability. Newer CMMs made use of lighter synthetic materials rather than traditional steel and granite designs. The introduction of the digital CNC controller has been used to deliver more accurate motion path and ensure circular motion paths instead of only straight lines. It has allowed operating a machine at higher acceleration levels and speeds. It is worth noting that all of these innovations to the CMMs are based on technology from outside of the industry.

Newer CMMs offer a lighter, more durable and tougher structure, and improve the dispersion of temperature changes. It results in higher accuracy due to decreased deformation of the structure. Another substantial innovation are measuring scales that increase the accuracy of the machine in all environments.

The granite base still used by many large CMMs would be recognisable by the earliest machine operators. This has barely changed at all in design or composition. If it’s not broke, don’t fix it!
However, the use of new probe types demanded a better structure as more forces are involved. COORD3 introduced Silicon Carbide bases, which is stiffer and lighter and has better properties compared to granite, although this has not been universally adopted by manufacturers.

Computerised Metrology

When low-cost PCs were introduced into businesses in large numbers in the 1990s, geometric error compensation allowed for improving the accuracy of CMMs and reducing the cost of inspection.

Nowadays, CMMs rely upon the position of the recorded probe points and the data coming from special software that calculates the position. In the past, the probe could only provide an assumed position.

The Biggest CMM Industries Around The World

Every developed country in the world has their own CMM industry, with the largest company being the British company Ferranti. They licensed their innovation to the US Bendix Corporation in the 60s, which became the main CMM supplier in America. Nowadays, Ferranti offers Merlin CMM, Impact CMM and the Umpire CMM. Most of the machines use Camio CMM software. LK CMMs were bought by the Belgium Company Metris in 2006 and then re-branded as Nikon Metrology for a Japanese market.

In Italy, there are companies that mostly produce CMM Gage and Shop Floor CMMs. They introduced Flexible Metrology to Shop Floor Gaging in the 1990s. Nowadays, the biggest CMM company in Italy is DEA, which operates all over the world.

In France, Ceramic Structure CMMs are the most popular. The biggest company is Renault CMM, which also operates in the US. Metrolog 2 metrology software was developed in this country.

In Germany, the largest CMM company is Zeiss, with Wenzel, also based in Germany, being the fastest growing CMM company in the EU27 as a whole. Together with Steifflmeyer and Mora, they developed Horizontal CMMs. They also have local high accuracy CMMs with scanning probes. Nowadays, the Zeiss Vast CMM system is one of the most popular in the automotive industry.

In Switzerland, PC based Metrology Software became widespread in the 80s and introduced advanced user-friendly features into CMM systems. Today, however, the company who invented this (Metromec) belongs to the German company Wenzel. They are still one of the main suppliers of CMM software.

In Japan, we find Mitutoyo, which is the largest single manufacturer of Metrology Equipment in the world. They sell their products in many different countries and their Crysta Apex CMM is one of the best-selling ever.

Ferranti licensed their original technology to Tokyo Siemitsu, which resulted in the development of local CMMs. Mitutoyo has their own range of models and the most popular is the BN series.

In the US, there are lots of CMM manufacturers, with Hexagon Manufacturing Intelligence and Sheffield being the most popular brand that operates worldwide. Sheffield was launched in early 1800s, and their latest CMMs are the Discovery and Endeavor models.

Sheffield FLB is one of the most utilised CMM programming languages and is used all over the world, while Hexagon’s PC-DMIS series of metrology applications are rapidly becoming the industry standard across all brands of CMM.

Aside from the biggest players, smaller companies also operate in the US, such as Taurus, Helmel, Elm Systems, Starrett, and so on. Starrett has stopped developing its own machines and started selling the Metrolog 2. One of the newest players in the market is Xygent, which offers advanced software with full CAD capabilities.

To quickly summarise the world's industry of CMM, there are 5 leading companies that play the biggest role in the distribution of CMMs:

  • Hexagon
  • Mitutoyo
  • Zeiss
  • Nikon
  • Wenzel

Some CMM companies that were founded over 20 years ago still use traditional materials adopted by the industry prior to the introduction of computerised finite element analysis modeling. Many of the companies sell traditional CMMs without advanced modeled data. Some believe these machines are outdated and can't meet modern requirements. This resistance to change to newer machines can be explained by their huge investments made in granite production facilities where other CMMs distributors can't operate.

There are many start-up companies in China and India nowadays that also produce granite CMMs. They are cheaper than newer ones and require less effort to manufacture frame designs. In fact, when it comes to the production of old-fashioned CMMs, more investment has to be made in tooling than to the machine structure.

However, this allows CMM manufacturers in the EU and USA to have access to a huge supplier base. Some of them have suffered economic pressures, leaving CMMs behind but, now, it's expected the new wave of CMM manufacturers operating in China and India may relieve some of this economic pressure.

The Core CMM Services Offered By Specialised Companies

CMM maintenance and training are two important elements of working with any machine. There are special CMM companies that specialise in the inspection of CMMs. They check the precision of measurements and supply data in the form of reports. CMM inspection is one of the most popular services provided by these companies. In addition to inspection, they also offer training, maintenance, surfacing, and digitising. Some CMMs can be inspected only on-site, while smaller portable CMMs can be examined in a special laboratory.

CMM installation is another popular service provided by CMM technicians. Even modern machines need to be checked yearly or they can fail to provide precise measurements. Just recently, the ISO 10360 CMM Accuracy Standard was published in order to increase the quality of service.

Most modern CMMs have Air Bearings that can wear and tear with time. Therefore, CMM retrofit and upgrade is necessary to keep the machine running efficiently. Basically, a technician adds newer technology to an older CMM (for example, better software). This service prolongs the lifespan of a CMM. This is the sector we are involved with at Status Metrology.

Some companies also offer to buy used CMMs and then upgrade and retrofit them to meet the growing industry demands. Oftentimes, CMM training is required in order to operate the machine efficiently and get accurate results. Company members can attend special classes or receive on-site training.

Contract programming is another popular service being offered by CMM service companies. The creation of computer programs can take place using the Customer CMM, CAD files, or a special programming language. There are also off-line software modules that help import CAD models, for example, Silma, Deneb, PC DMIS, and Delmia.

CMM service companies exist all over the world and specialise in different software and hardware.

Portable CMMs

Nowadays, many CMM manufacturers have their own portable and mobile CMM models as they become more and more popular worldwide. Other manufacturers develop their own bespoke metrology software for individual clients.

Status Metrology

At Status Metrology we are proud to have played our own little part in the history of the CMM by providing high quality supply, maintenance, repairs and upgrades to our clients for over 30 years. To find out more, please get in touch by phone on 0115 9392228, or send an email to info@status-cmm.co.uk

Image credit: Metrology News

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