Company News

Infographic: How to Choose The Right CMM for Your Quality Process

how to choose the right cmm for your quality process


The quality inspection process is a vital part of the day to day operations of a manufacturing business. Manufacturers across all sectors need to maintain exceptional quality whilst delivering products on time and as efficiently as possible. In many cases, Coordinate Measuring Machines are the most important factor in the quality inspection department and their performance can make or break your business. Product quality does not only depend on the quality of the machine tools used for manufacturing; it also depends on the accuracy and repeatability of measuring and inspection devices.

With this in mind, quality managers and directors are often faced with finding the best CMM for their department that will consistently deliver accurate results. However, with a range of options available, it’s sometimes difficult to understand what solution would work best.

We’re here to help. Take a closer look at how to choose the right CMM for your quality process…

Measuring Range

The first place to start in determining which CMM is best for your specific quality process is the measuring range. For this, you need to determine what the minimum required measuring range of the CMM needs to be and this will depend on the dimensions of what is being measured. As a rough guideline, Status recommends choosing a machine that has X, Y and Z measuring ranges that are double the dimensions of the largest components you will be measuring.

Minimum Required Uncertainty

The next thing you’ll need to consider is the minimum required uncertainty. Uncertainties for CMMs come off the back of verification and performance testing. They are described in ISO 10360-2 but some manufacturers conform to other performance standards. Again, as a rule of thumb, the CMM datasheet specification should be five times more accurate than the tolerance being inspected.


The uncertainty of every CMM depends to a great extent on environmental conditions. Variables such as room temperature and vibrations can have a huge impact on CMM inspection so these must be taken into account before deciding on a machine. CMM manufacturers will usually specify a CMMs temperature range data and the maximum vibration levels that the machine can withstand.

Types of CMM Machine

There are four basic types of stationary CMM machines on the market:

The most common type of coordinate measuring machine. There are fixed bridge and moving bridge variants. In a moving bridge, values on the Y-axis are determined by moving the entire bridge over the granite base and in a fixed bridge, values are determined by moving the table rather than the bridge.

Cantilever CMMs are restricted to smaller measuring ranges as the measuring head is only attached on one side of a rigid base. Cantilever CMMs are mostly used for measuring gauges and master parts.

Horizontal Arm
While less accurate than other types of CMM, Horizontal Arm CMMs are perfect for measuring sheet metal parts and large-volume components. They are particularly popular in the automotive industry as rail-mounted models can easily handle large-volume parts such as car bodies and panels. Their designs also enable the two arms to reach areas that would otherwise be inaccessible to a bridge CMM (such as inside a car body).

A gantry CMM is fairly similar to a standard bridge CMM but generally far bigger. The bridge for a gantry-style machine is instead mounted on top of pillars which increases measuring volume. The large volume and high levels of accuracy make gantry CMMs a popular choice in aerospace manufacturing applications.

As well as these, there are now an array of portable measuring options available such as Hexagon’s Absolute Arms. Portable arms offer incredible versatility and flexibility when compared to standard CMM machines. The key benefit being the ability to take the measurement device out onto the shop floor – instead of having to remove components from the manufacturing environment and bring them into the lab.

New Vs Used

Once you’ve decided on the type of CMM machine and determined the accuracy and measuring range etc. it then comes down to whether you should buy a new or used machine. This decision will mostly depend on your budget and while the latest showroom CMM models are fantastic, the Status range of used CMMs can deliver exceptional accuracy, reliability and value.

Status provides a wide range of both manual and automatic machines that have been refurbished to our approved standard. Every CMM is fully checked, refurbished, repainted and retrofitted with the latest metrology software (PC-DMIS) and equipment (including Hexagon RC Line controllers), giving our pre-owned CMMs the capabilities of newer machines and models – for a fraction of the cost of new!

Take a closer look

Get in touch with our CMM sales experts today for further advice on how to choose the best CMM for your quality process and individual requirements. Either call us on 0115 939 2228, email or complete our enquiry form at