Dimensional measurement and geometric analysis have historically been performed using contact-based measurement devices. In current times, however, there are several industries that rely on non-contact measurement. Such requirements can stem from a range of applications. Object sensitivity, high-precision measurement, and automation are a few examples of these advancements. In this article, we will go through the fundamental aspects of non-contact measurement. We will also dive into its details and discuss non-contact measurement solutions for businesses.
Non-Contact Measurement
As you might assume from the term itself, non-contact measurement means measuring an object without physical contact. We have developed nuanced techniques over the years to achieve this. Each technique analyses the object’s geometry from a distance. Not only this, it extends to physical properties, too. Over the years, some non-contact measuring techniques have become staples. There are laser-based vision, optical, and ultrasonic systems. What’s so special about non-contact metrology? It delivers high accuracy – with observational repeatability. The precision of non-contact systems can go up to nanometers!
Principles of Non-Contact Measurement
Non-contact metrology engages tools to obtain an object’s dimensional data. The data is acquired without physical contact. It leverages technologies that scan an object at a distance using sensors. The simplest form of non-contact measurement is optical measuring devices. They recreate object models through imaging techniques. Other forms of non-contact technologies are laser-based systems and ultrasonic waves. Click here to see the difference between non-contact and contact measurements.
How Does it Differ from Contact Measurement?
Contact-based metrological tools need to physically engage an object to measure it. This may be in the form of touch probes, electric signals, or instrument clamps. It creates an inherent limitation to the kind of object they can measure. What if the workpiece is too small, like a PCB? What if it is easily deformable, like a surgical implant? Non-contact measurement forgoes this limitation by scanning the object at a distance. It allows for greater flexibility, variety, and simplicity of measurement. By reducing human operational requirements, it increases the reliability of measurements.
Types of Non-Contact Measurement Technologies
Laser-Based Systems
Laser scanners are the veritable cutting-edge of modern metrology. The fundamental principle behind laser measurement is actually quite simple. Distance measurement is done through time-of-flight. What does that mean? Essentially, laser systems get the distance by the time it takes the beam to travel. What is the travel path, you might ask? From the sensor to the target and back. Laser triangulation is an advanced metrological technique. It deploys multiple sensors (cameras) over the stage area. Placed at specific angles, the cameras capture reflected light. This tells them what they need to know about the object’s dimensionality.
Optical Systems
Optical non-contact measurement involves imaging. We photograph the target and analyze the dimensions from the image. Photogrammetry is a popular technique in recent times. The object is shot at multiple angles, and the images are analyzed. It gives a comprehensive reconstruction of its features. You might frequently hear of white light interferometry; it’s another optical technique! It emits white light from many points at the object. What does that result in? An interference pattern. It turns out that this can supply much information on the object. Material properties, topography, and dimensions, all can be gauged from this simple technique.
Ultrasonic and Radar-Based Systems
Ultrasonic and radar rely on one thing – sound waves. These systems utilize high-frequency sound to investigate materials. Their operating principle is actually very similar to lasers. They, too, count the time taken for the sound wave to bounce back. Ultrasonic sensors have immense coverage area and versatility. However, they might be less accurate in certain conditions. As a bonus, they can operate in liquid and solid mediums. They, however, cannot operate in a vacuum. Sound-based measurement easily detects faults in pipes, tanks, or metal sheets.
Importance of Non-Contact Measurement
High Precision and Accuracy
Contact-based measurement devices can interfere with the workpiece. They can affect its dynamics and physical characteristics. In a critical industry, this is not acceptable. What if you measure discrete, miniature products like electronics and medicine? Non-contact measurement solutions preserve the integrity of the object. What’s more – they do it with brilliant precision and exactness. The obstruction to an object’s surface is minimal. They can reproduce surface profiles in a matter of seconds. Pretty good, right?
Non-Destructive and Safe for Delicate Objects
There is no doubt that human operators have been invaluable to the manufacturing industry. However, when dealing with delicate objects, it gets complicated. Firstly, human inspection is time-consuming. Secondly, worker wages are expensive. Is it any wonder that non-contact measurement is invaluable to industries? Something as delicate as a medical implant is inspected in seconds! These workpieces require effort and time to process traditionally. With optical scanners, you can save your expenses while boosting productivity. There are several other examples of workpieces that require a non-contact measurement approach. It can easily examine molten metal, hot automotive components, or radioactive materials.
Speed and Efficiency in Data Collection
Industry automation is one of the significant developments of the 21st century. Machine-based inspection has replaced several laborious tasks. The first to go out of fashion was manual inspection. A large thanks to non-contact metrology. These systems specialize in collecting enormous data chunks in short durations. Oftentimes, they are capable of providing real-time monitoring. It is indispensable for quality control and autonomous decision-making. They collect massive amounts of data. It is the ideal bedrock for refining manufacturing and improving business methods.
Versatility Across Materials and Surfaces
Industries employ several materials in their manufacturing process. Conventional metrology is sometimes inadequate to keep up with this dynamic. Non-contact measurement devices prove indispensable for materials and surfaces. Some examples are organic, ceramic, metallic, or composite materials. Non-contact devices inspect all these with ease.
Non-Contact Measurement Devices
Vision Measurement Machine (VMM)
Vision-measuring machines are versatile optical devices. They utilize imaging techniques to analyze properties. The primary components of VMMs are optical sensors (CMOS or CCD cameras). In addition, they have optical zoom lenses and measurement software. VMMs require adequate lighting to function appropriately. They reconstruct the workpiece in 3D. Extrapolating its image from multiple angles, they construct a CAD model. VMMs make manufacturing pipelines work autonomously. Widespread applications include barcode scanning. It is in retail and supply chains. Electronics, medical components manufacturing, and quality inspection are also critical applications.
Координатно-измерительная машина (КИМ)
Traditionally, CMMs have been contact-based measurement devices. However, modern CMMs come with optical or laser-based probes. These attachments have appropriate software support. With these tools, CMMs perform non-contact-based measurements. They still perform traditional functions. Optical CMMs have elevated industry capabilities. CMM users can now extend their measurement arsenal with a few modifications.
3D Scanners
3D Scanners extract the critical features of an object by converting it into a 3D model. Thanks to multiple-angle imaging. Once a 3D scanner acquires attributes, it compares it to the design specifications. Through this process, 3D scanners validate manufacturing processes. They are critical for identifying minute deviations and defects. 3D scanners help industrial devices perform pass/fail checks. They enable product reverse engineering and design validation.
Laser Triangulation Sensors
In laser triangulation devices, an emitter throws the laser beam on the object at various angles. The reflected beam is measured at angles by a CMOS camera. The process gets a comprehensive report of the surface. It includes distances, dimensions, profiles, and material information. Laser triangulation is a versatile technology. It is present in quality control stations, automated assembly lines, and surface inspection, among other applications.
Ultrasonic Sensors
The ultrasonic sound band is 20kHz – 200kHz. In these frequencies, waves can travel a long distance with minimal attenuation. It is the reason ultrasonic sensors work so well on uneven, fractured, or clear media. Ultrasonic measurement devices consist of a transducer that emits and receives sound waves. It determines distance and profile by the time it takes for the sound to bounce back. Ultrasonic measurement is indispensable in length measurement. It also enables particle sensing, volume checking, and proximity scanning.
Application of Non-Contact Measurement
Fabrication and Manufacturing
Today, workshops are steadily increasing the level of automation in their practices. One of the most noteworthy enablers of this evolution is non-contact measurement. It has surged the precision levels involved in manufacturing. Lesser human dependence on operational tasks means more reliability and increased efficiency. Several industries (like electronics) depend considerably on non-contact devices for product inspection.
Aviation
Aviation and aeronautics are critical industries. They require rigorous global standards. Only high-precision non-contact measurement can meet their conditions. Optical and ultrasonic sensors provide accurate measurements. They can profile complex assemblies. Laser trackers carry out wing alignment according to detailed specifications.
Cars and Automobiles
Many industries in the automotive sector have traditionally used CMMs. It is, however, very easy to migrate an existing CMM to an optical CMM. It adds to your measurement arsenal. Previously, you may have measured car frames and panels. With optical CMMs, the range of product inspection increases dramatically. It enables workshops to process more projects themselves rather than outsourcing.
Medicine
Medical machinery is another industry that requires the highest precision and quality. Critical devices in this field include CT scanners, MRI devices, body or neural implants, and medical aids. Non-contact measurement devices perform defect detection. They ensure that small and delicate machine components are faultless.
Электроника
Optical measurement tools are critical for any electronics workshop. Chip sizes are rapidly decreasing across the industry. Consequently, humans can no longer manually inspect them. Non-contact measurement devices effectively process microelectronic components: PCBs, semiconductors, capacitors, or inductors.
Заключение
Innovation in science is in full throttle. Measuring technology spearheads this progress. Non-contact metrology represents a significant shift in design and production globally. Its ability to transform the industry is unquestionable. It does this by delivering highly accurate, quick, and non-interruptive measurements. The ability to measure remotely has several implications that are still not studied. Non-contact measurement growth is steady with the pace of machine vision and AI. For further queries regarding non-contact metrology, contact our team of industry experts.