3D Coordinate Metrology - An Important Cornerstone in Industrial Quality Assurance

3D coordinate metrology is one of the most precise inspection methods available. Due to the high technical requirements, it is mainly used for prototypes, individual parts and random samples. The components can be measured in their entirety with absolute accuracy. Two important representatives in this field are tactile and optical measuring methods. 

‍

What is 3D coordinate measuring technology? 3D coordinate measuring technology determines three-dimensional coordinates using a measuring arm, a coordinate measuring machine or an optical scanner. The measurement accuracy achieved is in the micrometer range. It is one of the most precise variants in the industry. The measurement data generated subsequently serve as the basis for creating measurement protocols and as a foundation for quality control.

‍

At Q-Tech, 3D coordinate measuring technology plays an important role. In this article you will learn more about how the machines work and which ones we use.

‍

Basics & Functionality

‍

The technology is used to measure objects in a three-dimensional coordinate system. Various devices are used for this purpose. These can be coordinate measuring machines, gantry measuring machines, laser scanners and optical systems. 

‍

With the help of these technical possibilities, it is possible to capture complex shapes and geometries and measure them with the highest accuracy. 

‍

During the process, the machine detects the position of an object in space and determines the coordinates of individual points. The whole thing is done with the use of the three coordinate axes: X, Y and Z. These axes are arranged in a Cartesian coordinate system.

‍

Some modern devices in 3D coordinate metrology also use a combination of tactile and optical measurement methods to achieve higher measurement accuracy. 

‍

In the tactile variant, a probe touches the component to be measured at the various points. The probe detects the position of the points and returns the information to the measuring device.

‍

Optical methods use a laser beam or camera to scan the surface of the component and digitize it for downstream measurement.

Areas of application

‍

Coordinate metrology is used in quality control, product development and industrial manufacturing . Relevant industrial areas are aerospace, automotive and medical technology. 

‍

Today, such precise measurements are essential for checking certain specifications and improving product quality.

‍

‍

Preparation for the measurement

‍

A measurement with a 3D coordinate measuring system requires precise preparation. Among other things, because in this field the metrologists check highly accurate dimensions. Therefore, external factors also have a great influence on the measurement. 

‍

Most important are: 

‍

• Properties of the probe head: Depending on the measuring system, different probe heads can be used. These differ in shape, diameter and size. The characteristics of the component are decisive for which measuring head is used. Before starting the measurement, the measurement technician must select a suitable probe head.

‍

• Ambient temperature/workpiece temperature: This parameter is one of the crucial ones in preparation. The reason is that metals in particular expand under the influence of heat and contract again when cold. With a larger component, the resulting forces and form deviations are all the more serious. Because of these physical conditions, the ideal place for a measurement is an air-conditioned laboratory and an annealing cabinet. In this, the component is brought to the ideal measuring temperature. This eliminates any form deviations due to the influence of heat.

‍

• Humidity: Humidity can be another disturbing factor. If this is too high, the measuring heads lose precision. This can falsify the results during the test procedure. As with the ambient temperature, a temperature chamber and air conditioning system can help to eliminate this interference factor. 

‍

Calibration of the probes

‍

Another important point in the preparation is the calibration of the probe tips. This is because the measurement data is primarily acquired by probing the component with a probe attached to the measuring axis of the device. 

‍

Relative to the coordinate system of the machine, the position of the tip must be precisely determined before measurement. The component is probed with the edge of the probe tip. In advance, the tester must determine the center and radius of the probe tip by measuring an absolutely precisely defined calibration sphere. 

‍

Once this process is complete, the machine or software mathematically adjusts the coordinates of the tip by the radius. In this way, the actual point of contact is calculated as soon as the machine touches a workpiece. The machine automatically determines the direction of this "offset". 

‍

Advantages

Now that you have an idea of how a coordinate measuring machine works, learn about the individual advantages of using this method of measurement.

‍

1. Precision: Properly calibrated and programmed, 3D coordinate measuring technology enables high-precision measurement of components. The data is processed by software to determine the actual condition of the component. Subsequently, the deviations in size, length, shape and position from the nominal values can be calculated. 

‍

2. Speed: The entire measuring process is relatively fast. This is very advantageous, especially in production, because it shortens the measuring time and increases cost-effectiveness.

‍

3. Flexibility: The technology is ideally suited for applications in the automotive and electrical industries, mechanical engineering and aviation. Thanks to its high precision, the method can also be used in the manufacture of medical devices. 

‍

4. Automation: Complete automation is definitely possible. This means that a measurement can be made quickly, reliably and reproducibly. This means that several identical components can be measured multiple times in the same position and orientation. Automated processes reduce the probability of human error and ensure increased quality of the measurement results.

‍

The measurement method in the future

‍

The pressure to innovate in this area of measurement technology is particularly high. 

‍

At the moment, the tactile 3D coordinate measuring machine remains the industry standard. However, other measuring technologies have already been able to establish themselves on the market as possible alternatives. However, it can be seen that there is much to be said for non-contact processes. 

‍

In the meantime, tactile and optical measuring methods are also being combined in order to achieve more meaningful results. Furthermore, older tactile methods in particular require significantly more time than optical variants. For this reason, measurement in the 3D coordinate system is often carried out with photometric methods if the components and tolerances are suitable.

‍

Instead of a 3D coordinate measuring machine, two digital cameras are then used, for example. After photographing the component, the computer generates a digital image that is freely displayed in a 3D coordinate system. The inspector can then rotate and measure the digital body in the software. 

‍

In addition to the photometric methods mentioned above, there are also other optical methods in 3D coordinate metrology: 

‍

• Strip projection
• Line sensors
• Laser scanning
• Gray value evaluation
• Contrast method
• Confocal and interferometric sensors
• Stereoscopic digital photography

‍

‍

3D coordinate measuring technology at Q-Tech

‍

At Q-Tech, we offer customized 3D coordinate measurements for our customers. 

‍

We rely on machines from the manufacturer ZEISS. The PRISMO ULTRA, PRISMO VERITY, ACCURA 7 and ACCURA II machines use modern tactile sensors to determine dimensional and shape deviations. 

‍

With the O-Inspect 863, we also have a machine in our portfolio that combines optical processes with the tactile method in one system. 

‍

We use CALYPSO as our high quality measurement software. 

‍

The decisive physical quantity that we measure at Q-Tech is length. We are therefore a service provider for length measurement technology. Our machines are ideally suited for this because they enable highly precise and meaningful measurements. 

‍

Challenges and limits

‍

3D coordinate measuring machines are excellent for checking dimensions, angles, and form and position tolerances. 

‍

However, keep in mind that a coordinate measuring machine can only inspect a component from the outside. Faults or defects on the inside usually remain undetected and cannot be detected.

‍

Industrial computed tomography is particularly suitable for this purpose, as it can also record the interior of components and detect faults such as cracks, blowholes, inclusions or pores there. 

‍

Are you interested in our computer tomographs or in our 3D coordinate measuring technology? Then take a look at our equipment. 

‍

Conclusion

‍

Today, 3D coordinate measuring technology is the ultimate in industrial measurement techniques. 

‍

Contours, lengths, and shape and position tolerances can be measured extremely precisely with these measuring methods. However, it can be observed that optical measuring methods are becoming much more established on the market. 

‍

For this reason, many manufacturers rely on a combination of optical and tactile measurement methods and are constantly working to improve established methods with even more powerful approaches. 

‍

The measurement service provider Q-Tech offers you perfectly tailored measurement technologies that meet all of today's modern standards and thus provide meaningful and precise measurement results. 

‍

Our qualified team of professionals is very concerned to provide you with the best possible measurement result for your components, so that you can be completely sure of the quality of the manufactured workpieces. 

‍