3D scanning is the process of collecting data from the surface of a physical object which accurately describes the shape in terms of three-dimensional space. Once collected, this data allows technicians, mechanics, engineers or hobbyists the ability to examine an object digitally, which enhances and maximizes the precision and speed of their work. By obtaining the shape of the part digitally, the scan data can be used to either replicate the part (reverse-engineering), or for dimensional analysis (inspection).
How does a 3D scanner work?
Getting a thorough understanding of the “what is 3D scanning” topic requires diving into how they work. There are a variety of different approaches to 3D scanning that we will explore below. At a high level, they work in a similar fashion: lasers, light, or sensors in the scanner detect the surface of the object being scanned, and assigns data points to the location of that surface. Those data points blanket the surface(s) of the part three-dimensionally, and are collected and compiled to digitally recreate the object in extremely accurate detail.
As you might guess from the name, laser scanners use triangulation to identify and value the location of data points on the surface of the object being scanned. Most laser triangulation sensors involve a single laser source that projects a laser line onto the surface of the object being scanned, and the shape of that line is being observed by angled sensing cameras. The angle between the laser source and the sensing cameras is determined through a calibration process. Because the angle between the laser source and the sensing camera(s) is known, the triangulation process can be calculated. Each pixel along the length of the laser line is triangulated and valued as the line is swept across the surface of the part. While laser triangulation can produce accurate scans, the technique has challenges with transparent and shiny surfaces.
Laser triangulation is just one part of the "what is 3D scanning" discussion. "What is 3d scanning technology?" is the next question we need to answer. The technology used for 3D scanning comes in many shapes, sizes and scanning methods. While the technology varies from machine to machine, the outcome of each is the same: to create a highly accurate recreation of the object in a digital environment.
Some machines are built to scan incredibly large objects down to each curve and jagged edge on its surface. Some machines are more compact and work well when collecting data on smaller objects. Also, depending on the type of laser, light, or sensor used, the level of detail and efficiency of making the scan can differ.
Structured light 3D scanning technology
3D scanning devices that use structured light are based upon triangulation as well. A projector is set up with two cameras at angles on either side. The sensing cameras analyze light patterns as they are projected onto the object being scanned. Exact X-Y-Z coordinates are calculated from the data and used for the creation of extremely precise digital models of the scanned object.
The projector in a structured light sensor emits a heterodyne “fringe” pattern of light that visually appears similar to Zebra stripes. Those stripes will change in size and direction during the very brief time of data collection. The sensing cameras pay attention to the contrast along the edge of the stripes, and values those pixels with X,Y,Z coordinates. The scan data collected with a structured light scanning system is highly organized, as well as being smooth and continuous, containing very little noise (texturing).
Structured light 3D scanning is a popular method of non-contact scanning in a variety of industries including prototyping, research and development, quality assurance, inspections, and reverse engineering. As structured light scanning eliminates the need for physical contact with the object, it makes workflows more efficient and produces more accurate and rapid results than contact based scanners like coordinate measuring machines (CMMs).
However, not all structured light technology is created equal. The color of the light used in a structured light 3D scanning device does impact the quality of the scan data that is collected. White light and blue light scanners are two of the most popular types of structured light 3D scanners. While white light 3D scanners offer advantages over CMMs, blue light scanners offer the highest quality scan results. The reason for this? Blue light has a narrower wavelength, making it more resistant to ambient light, resulting in very accurate and smooth scan data. For more on the topic, check out White Light vs Blue Light Scanning.
Photogrammetry is the practice of extracting dimensional information from high-resolution photographs. Instead of structured light or lasers, which are used in many other 3D scanning techniques, photogrammetry uses two-dimensional photographs which are bundled together in order to develop a three-dimensional data set. Photogrammetry is inherently a very accurate measurement technique, and is most often used in conjunction with an optical 3D scanning system.
Rather than a roving scan of the object’s surface, a camera instead takes photos from numerous perspectives and then needs the right software to be able to recognize common features from image to image, in order to bundle the multiple images together.
Photogrammetry can be performed using either a manual, high-end, handheld digital camera, or by using an integrated camera mounted on the end of a robot in an automated scanning cell. The photogrammetry process yields a very accurate framework of target locations that can then be utilized to link together the multiple patches of data that are collected using a structured light scanning system.
The technique used in contact-based 3D scanning is different in that it is a more invasive approach. A physical probe is used and the probe must make contact with the object's surface. A stationary probe is used if the object is moving while being scanned. The other approach is to use a roving probe that moves over the stationary object or a manually operated 3d scanning device like a CMM. The software used in conjunction with the probe will pick up on how and where the probe touches the surface and can thus record the three dimensional location of the surface. Contact-based scanning generally take significantly more time than other scanning techniques, and produces much lower resolution data.
Another name you might recognize for this technology is time-of-flight scanning. This method is a bit different in that it doesn’t utilize the typical triangulation scanning. Instead, it uses the speed of light and sensors to measure surface geometry.
Millions of pulses are sent from the laser to the object’s surface, which are then reflected back to the sensor. The timing of the pulses from the laser back to the sensor enables the collection of surface data in this type of scan. A mirror rotates the laser and sensor hardware, which allows the software to collect 360 degrees worth of data.
The use of technology today seems limitless, and its advancements are undoubtedly helpful. 3D scanning collects data that can give mechanics the power to take apart pieces with no physical destruction; allowing them to find problem areas, fix parts and take objects through test runs before even producing the physical object. They alert aerospace technicians to faulty parts that would have otherwise gone undetected until post-production. They open a whole new realm of anatomical studies for medical professionals, giving them a much more advanced vision of how to conduct invasive surgeries.
What does this mean? Less money being spent on production. Fewer iterations being made, which leads to less bottlenecking on the production line. A more efficient use of labor and time that leads to more productive workflows.
Although it can be expensive, the benefits of 3D scanning technology far outweigh the initial cost. When it comes to improving products, reducing waste, cutting cost and gaining a competitive edge, 3D scanning is the ultimate tool.
By utilizing the latest 3D scanning technology, manufacturers have access to higher-resolution, more accurate data than ever before. This information can be used to streamline production processes in multiple ways. By identifying problematic parts earlier, manufacturers can save both time and money by reducing development iterations. Further, 3D scan data allows for multiple parts to be assembled together digitally to assess fit and finish, before any physical parts get shipped. Understanding the dimensional characteristics of your parts is critical in today’s fast-paced, time-to-market environment.
Oftentimes, the software for 3D scanners will automatically create inspection reports, streamlining the manufacturing process for you and your employees.
From the start, 3D scanning has been utilized as a method to collect the shape of an item, which is then used to derive a 3D CAD model for reproduction purposes. In most cases, legacy parts produced several decades ago are only described within two-dimensional drawings, not 3D CAD. Through the 3D scanning of an object, the shape can be collected very accurately, and the resulting data used as a reference to create a brand new 3D CAD model. That model can then be used to create new molds/tooling, allowing a manufacturer to produce brand new parts that have the same dimensional characteristics of the original. The reverse-engineered CAD model can also be used to 3D print a duplicate of the original. High quality 3D scans help remove the guesswork in the reverse engineering process and make it more efficient overall.
Near-line and inline production produces the most streamlined workflows. The process is automated, which means little to no human intervention is needed. This gives employees on the production floor a lot more leeway to move about the floor ensuring everything else in the production process is up to speed. Automated 3D scanning improves quality control. It’s a great time saver and reduces bottlenecking.
One of the most functional elements of 3D scanning is that it allows for improvements of existing products. Besides that, it can also give mechanics and technicians a new way of seeing how objects work, and they might completely recreate a product to make it more efficient.
Developing products that people are going to be able to use and understand is a huge selling point for manufacturers. Designing a few iterations digitally and then watching how the new designs work via the software makes for a lot less frustration once the material product is produced on the line.
Building prototypes is a staple in manufacturing, and 3D scans can be turned into 3D prints that function as prototypes. As the names let on, additive manufacturing is when layers and pieces are added to the object. Subtractive manufacturing is when layers are taken away, or cut away, to reveal the finished product. While additive manufacturing is helpful with smaller products, subtractive manufacturing is a good choice for large parts.
Some manufacturers are involved with the re-manufacturing of older parts, which must be brought back to the dimensional characteristics of the original specifications. Often in these cases, each part is distinctly unique, making it impossible to simply re-run the original CNC cutter path during the remanufacturing process. 3D scanning the part serves as a basis upon which the CNC cutter path can be “adapted”, or morphed into the local geometric shape of the used part. The area of the used part that is to be remanufactured can then be welded, which adds material that will then be re-machined back to the desired shape using the “adapted” cutter path. This approach would not be possible without the use of 3D scanning technology.
There are a variety of 3D scanners available on the market today. These range from portable CMMs to laser scanners to blue and white structured light 3D scanners. For commercial use cases, structured blue light scanners tend to offer the most upside. For example, the GOM ATOS Triple Scan won the GE High Accuracy, High Throughput Inspection Technologies Challenge against a competitive field of 51 total scanners.
While that is impressive from a technological standpoint, what about a business perspective? Structured blue light scanners often win the day there too. Consider that the U.S. Army’s Aviation Missile Research, Development, and Engineering Center (AMRDEC) saved up to $100 million as a result of a project using ATOS 3D scanning.
Other popular 3D scanners include:
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Requesting a demo is a great way to get face-to-face familiarity with 3D scanning if it feels a bit out of your reach. We’ll show you the how 3D scanning can improve product design, streamline production lines and improve quality control.