While 3D scanning is often used as a comprehensive term, it actually represents several different types of equipment and best practices, only one of which may be right for your manufacturing application. This article discusses the key considerations in choosing the tracking needed for your work. Article by Automated Precision Inc. (API Metrology).
As manufacturing deadlines grow tighter and their tolerances more demanding, 3D laser scanning has become one of the most sought-after quality control processes across all industries. The ability to capture hundreds of thousands of points per second has made 3D laser scanning a fast and efficient tool for rapid point-could generation, 3D CAD modeling, part inspection, and Building Information Modeling (BIM). And in many industrial environments, 3D laser scanners are now used to supplement, if not outright supplant, probe or touch scanning measurements.
But while 3D laser scanning has become a catch-all term used by facilities looking for scanners and service providers, the applications that term represents actually cover a wide-range of equipment and techniques. And these different scanners are each only appropriate for a specific set of the applications listed above. So, how can you know which 3D scanning service or piece of equipment is the right one for your application? The best way to begin narrowing down the options is usually by looking at the size of the part or area that needs to be scanned and the tolerances that scan will need to meet.
When we approach 3D laser scanning from this perspective, most scanning applications fit into one of three categories:
Small Part Inspection Work
For many manufacturers today, the most common application of 3D laser scanning is for inspecting small parts for prototype inspection, reverse engineering, CAD comparison, and other quality inspection checks. This scanning work is usually performed on pieces smaller than a few meters in length or diameter. And, fortunately for quality inspectors, there are several tools that can perform these kinds of checks, from hand-held scanners to multi-axis arms. The key for these inspections is accuracy, which is why the equipment that is best for small part inspection work typically uses Triangulation to produce the most accurate data.
Triangulation for 3D laser scanning is a process where the laser emitter, the laser point on the inspected part, and the scanner’s high definition camera make up the three points of a triangle. The software uses the known quantities of the distance between the laser emitter and camera and the angle at the laser emitter’s corner and calculates the camera’s angle to the laser point to discern the rest of the information about the triangle. This allows the distance between laser emitter and laser point and the angle of the point to the camera to be analyzed.
The laser’s beam contains hundreds of thousands of these points that are moved across the part every second, and the software records the changes in distance and angle to repeatedly calculate those triangle values for each point and create useable surface information in a working computer model. This virtual model of the part can be used for CAD comparison, part or mold validation, reverse engineering of a new CAD model, and more.
Digitalisation and measurement made it possible to modify mould inserts and allow them to be exchanged, thus avoiding downtime for this manufacturer. Article by GOM.
Triple Scan Principle. (Image source: Lometec)
In the past, measurement service provider Lometec had ‘merely’ conducted some workpiece first-sampling for one of its customers, a well-known medium-sized plastics processor. But when an urgently needed, brand-new tool suddenly failed, the metrologists moved out on a special mission: Delivering overnight service, they digitalised the mould tools using GOM scanning systems so that precise, rapid reworking was possible. The impending default on delivery was averted.
Lometec’s customer produces, among other things, thermoplastic weather-proof housings designed for use in extreme climates. When the quantities in demand began exceeding the existing tool’s capacities, the company commissioned construction of a second, identical tool—and that’s where the trouble began.
Tool Failure After Passing First Sampling
At first, everything was looking hunky-dory: The new tool was delivered and worked just fine, as verified by Lometec as part of first sampling of the housing. The 3D measurement service sampled 125 parts and recorded the results in the initial sample test report (ISTR). Process capability was validated and the plastics processor was able to produce with two tools at once, doubling output as desired.
But shortly after starting mass production with the second tool, it proved prone to faults: Sliders and inserts began seizing. The tool manufacturer responded promptly to the complaints and supplied spare parts—but these did not match precisely, making it impossible to simply exchange them, never mind swapping over the sliders and inserts between the two tools.
The Solution: Scan and Rework—ASAP
This gave the plastics processor the idea to have Lometec digitalise and measure the 14 affected mould inserts and sliders. The measuring data would then be used to rework the imprecise spare parts.
Lometec Managing Director Jörg Werkmeister remembers, “Our job was to compare the old inserts with the new ones and return all of the inserts to the company again as quickly as possible, so they’d be able to keep on producing with one tool at least. Having both tools measured was naturally stopping production completely.”
No sooner said than done: being specialists for rapid optical 3D measurement, Lometec was confident they had what it took. The measurement service maintains two fully climatised measuring rooms and uses measuring equipment by renowned German manufacturers, including three GOM systems for full-field digitalisation of technical mould halves.
“We set up the 3D scanning lab completely from scratch in 2016, it’s absolutely state-of-the-art,” Werkmeister says. “Our trio of ATOS Triple Scan, ATOS Core and ATOS ScanPort means we’re excellently equipped for a diverse range of digitalisation jobs.”
Investing in GOM technology had been very good decision, Werkmeister goes on to say. “The measuring data the systems supply are outstanding.”
To meet the demand for promptness, two metrologists tackled the plastics processor’s job in tandem: one working with ATOS Triple Scan, the other with ATOS Core.
Before conducting the measurements, the metrologists cleaned the sliders and inserts, removing residues such as grease and the like. Next, they applied high-precision reference point markers. These ensure that the software joins the separate scanned images correctly.
“For digitalisation, we chose really small increments,” says Werkmeister. This achieved high detail resolution.
Here’s how one company was able to streamline its reverse engineering process and carve out a competitive advantage in their market. Article by Andrei Vakulenko, Artec 3D.
There are multiple reasons a manufacturer would need to reverse engineer an existing object. From recreating an original item to enhancing designs to creating entirely new products, the process of reverse engineering can help manufacturers improve their production processes and enhance product effectiveness. In fact, the ability to break down an object to see how it was created can often be a capability that entire businesses or specific services are based around – this was certainly the case for Taylor Attachments.
Taylor Attachments is a UK company that custom-designs and produces tractor headstock conversion brackets. These include attachments for farm handlers and loaders used for mounting everything from buckets to forks, grapples, saws, carriers, bale stabbers, grabbers, hitches, backhoes, tillers, yard scrapers, and more. Clients of Taylor Attachments also send them legacy equipment—equipment that is outdated, obsolete, or no longer in production—which Taylor’s specialists precisely measure and reproduce using the latest materials and technologies.
In the past, this reverse engineering process was 100 percent manual, which meant a long seven to 12 hours of making sketches using rulers, callipers, pens, and pencils to trace out each machine part and component on cardboard and paper, before creating mock-up prototypes for testing. The entire process entailed cross-referencing and double-checking that would take anywhere from seven days up to two to three weeks (and was prone to human error as well). In total, it required one to three weeks to create design specs for each part, throwing a huge delay into their production workflow if a prototype did not fit right away. Although spending up to three weeks per part may seem like an extended amount of time, it is the current industry average, and a timeline that many still struggle with today.
While Taylor might not have much competition in this area, many similar businesses are still using the old process described above, or a similar workflow, for their in-house manufacturing of replacement headstocks. With the help of the latest technology, Taylor saw the potential to move ahead of other businesses and carve out a competitive advantage in their market.
“The requirement to manufacture more of these products from varying sources meant that we were going to tie up far too many man hours along with encountering possible inaccuracies to make it viable,” said Mark Taylor, president of Taylor Attachments.
The team at Taylor Attachments knew that this arduous process—requiring lots of fine-tuning before each product was ready to be shipped to the client’s doorstep—needed upgrading. Taylor had already made the transition to 3D CAD software, using SOLIDWORKS from Dassault Systemes. In researching new ways to improve their reverse engineering process, the Taylor Attachments team was introduced to Europac 3D, a company that specialises in everything 3D, including software, printers, and structured white-light scanners. Europac 3D helped Taylor Attachments make the call to extend its 3D workflow by adding 3D scanner technology from Artec 3D to accelerate its design cycles and increase the accuracy of its projects. Europac 3D recommended the Artec Eva, a 3D scanner used for capturing medium-sized objects such as an alloy wheel or a motorcycle exhaust system quickly and precisely.
When Taylor Attachments first implemented the Artec Eva into their reverse engineering workflow, they noticed improvements right away. The 3D scanning process works by flashing a grid pattern of light over an object, where it becomes distorted across the object’s surface topography. The distorted pattern is then reflected back to the scanner, where it is measured. Each flash of light provides XYZ points or polygons. As the object is scanned from various angles, the data from the multiple flashes are fused together using mathematical algorithms to create a digital model. So, instead of manually measuring and drawing parts, the Taylor Attachments team gained the ability to scan and create an exact digital 3D model of each part. With all of Taylor’s replacement headstocks being designed in-house and sold both nationwide and abroad to leaders in agriculture and industry, minimising their turnaround time so dramatically has made an immense difference—both the volume of work they’ve been able to take on and manage, as well as maintaining the utmost levels of quality that they’ve been famous for.
“Eva has literally saved us days if not weeks of work, and that’s no exaggeration,” said Taylor. “Previously we were spending all that time creating prototypes to test, then that many more hours on alterations to reach the level of perfect, compared to now achieving perfection the first time, and every time, with Eva.”
The new integrated workflow created using Artec Eva and SOLIDWORKS has completely overhauled Taylor Attachments’ manual processes. Aside from just the time savings with 3D scanning, there were other bottlenecks with syncing the manual measuring process to the 3D CAD work, including difficulties building relationships with other profiles on the same part, especially if there were no common features to link to. This hurdle has been easily dealt with via 3D scanning.
Taylor says, “Now with Eva, it takes only about 20 minutes to scan an entire headstock, then another 20 minutes to post process everything in Artec Studio, and after that the 3D model from Studio is sent over to our in-house design team. What they do is use the Xtract3D add-in for SOLIDWORKS to create a beautiful, highly-precise 3D model that’s 100 percent ready for production.”
After this process, the model is immediately sent over to one of Taylor Attachments’ laser cutting partners, all of whom work to the highest standards. For each individual project, everything from start to finish takes less than 24 hours, a drastic difference compared to the seven days to 2-3 weeks it took before 3D scanning was implemented in their reverse engineering process.
For Taylor Attachments, the addition of 3D scanning into their reverse engineering work has been invaluable for the improvements it has brought in terms of a streamlined workflow and greater efficiency. What used to be a long, laborious, manual process is now something they can complete in less than a day’s time. Taylor Attachments left their old process behind and have welcomed in the new era of reverse engineering. 3D scanning is setting new standards for these applications, replacing antiquated, labour-intensive and error-prone techniques. In the words of Taylor, “There’s simply no going back for us.”
Here’s how BMW in Munich was able to increase process reliability for front and rear end assembly. Article by Carl Zeiss.
The ZEISS T-SCAN fulfils the highest demands with regard to ergonomy. For this reason, larger components can also be scanned without fatigue.
The front-end decisively characterises the silhouette of a vehicle. For this reason, perfect assembly and strict adherence to the joint plan are of great importance to car maker BMW. For a long time, gaps have been tested only with gap gauges. In this process, deviations of tolerances are effectively visualised, however, it does not contribute to determining the cause of an error. In the past, in order to track down this error, vehicles with a conspicuous joint and gap profile, therefore, had to be driven to the measuring room and measured there.
So, the department searched for a digitising system to optimise the assembly process. It should be used right after the final assembly and should provide as precise results as did the system in the measurement room.
Intuitive 3D Scanning
The hand-held ZEISS T-SCAN laser scanner enables fast, intuitive, and highly precise 3D scanning. Hand scanner, tracking camera and the touch probe are perfectly matched. The modular system can thus be used for numerous applications. Here, the unique scanning speed and the precise measurement results are of great value. This is because the surface of the component is scanned contact-free and lightning-fast with the help of the laser line generated in the hand scanner. Around 210,000 points per second are recorded—more than with any other conventional method. As the tracking camera detects the position of the scanner, 3D surface data can be calculated with the help of triangulation.
With the touch probe, it is also possible to take tactile measurements of additional single points, for example, in order to capture hole edges or not observable depressions. The data captured with the ZEISS T-SCAN thus describes the actual state precisely. This can then be easily compared with the target specifications, as defined in the CAD model. Deviations can be quickly detected in a user-friendly way with a false colour comparison of the entire surface.
As the ZEISS T-SCAN also fulfils the highest ergonomic demands, fatigue-free scanning even of larger components is possible. Thanks to the light and compact scanner housing, the ZEISS system can also easily capture data in areas that are difficult to access. The intuitive and easy handling extend the range of applications or user groups.
Single point 3D data acquisition at optically inaccessible areas with the touch¬probe ZEISS T-POINT.
Since March 2016, three assembly workers have been inspecting front and rear ends of an average of six completely finished vehicles per day. As a result, joint and gap widths of the two-part and rounded off radiator grille, the so-called BMW kidney, the headlight, and the bumper are measured. The briefly trained operators of the ZEISS T-SCAN capture 80 to 90 measurement points at the front end and 40 measurement points at the rear end of the various models. The measured actual values are then compared with the set values of the CAD model. Within two hours, it can be determined whether the front and rear ends show any defects. In this way, the quality engineers of assembly and body construction can counteract much faster.
For the quality and process engineers, the ZEISS system is therefore an important prerequisite to more effectively control in-house processes as well as those of the suppliers. Thanks to the portability of the ZEISS T-SCAN system, the apparatus for the assembly of the front and rear end can be measured directly in the production hall.
Here’s a look at the development path of the world’s first direct scanning laser tracker. Article by Joel Martin, Hexagon Geosystems.
Manufacturing innovations have often been the driving force behind new developments in the field of metrology—the science of measurement. New combinations of hardware and software are allowing engineers to solve problems in new ways that simply weren’t possible before.
In the late 1990s, technological advancements delivered a new device known as the laser tracker, which has gone on to establish itself as a worldwide standard for large-scale alignment and verification tasks. A laser tracker is a portable coordinate measurement machine (PCMM) that uses a laser beam to accurately measure and inspect the features of an object in 3D space. This beam is sent to a spherically mounted retro-reflector touching the object to measure two angles and a distance, thus calculating its position and defining it with an X, Y, Z coordinate.
Laser trackers were quick to find their home in large-scale manufacturing, largely because no other measurement solution could accomplish such tasks. They allowed engineers to perform wing-to-body alignments or even tooling verification faster and more accurately than ever before. But the first generation of laser trackers had their own special issues, such as when line of sight between the laser tracker and the reflector was interrupted and the operator would have to walk the steel sphere back to a home position to pick up the laser beam from the tracker.
This limitation reduced operator efficiency, and consequently cost money, especially if the reflector was being tracked from a distance of some 20m away. While workarounds were available, it was not uncommon to see the connection interrupted repeatedly if there were physical obstacles in the work area such a workers or cables.
The solution to this issue was first provided by Hexagon in 20XX when the PowerLock feature was first introduced to their Absolute Tracker range of laser trackers. However, laser trackers still required the skilled hand of a well-trained operator to deliver reliable results.
A Breakthrough Driven by Automotive
The next great development in the history of laser tracker systems came after a major automotive OEM challenged several metrology leaders to design a system that could track a handheld device capable of non-contact scanning a surface around an area the size of a car with tracker-like accuracy.
Although it wasn’t immediately met, this challenge was behind the introduction of the first large-volume wireless probe, which worked like a “walk around CMM” by allowing the operator to use its common stylus to measure a part in a way similar to using a CMM or portable measuring arm.
This breakthrough was made possible by the introduction of a new type of laser tracker that, rather than simple 3D measurement, could measure with “six degrees of freedom”. These “6DoF” laser trackers, the first of which was the landmark Leica Absolute Tracker AT901, were capable of measuring not just a single point, but an orientation around that point about a full six axes.
Most importantly, from a productivity standpoint, this new device allowed the measurement of hidden points within recesses, or simply points on the back side of the measurement object, without repositioning the laser tracker.
Early benchmarks showed that this new probing capability could provide an increase in throughput of up to 80 percent over traditional reflector measurement. This technology created such a dramatic shift in the way objects were measured that the reflector—the very tool that had until now been key to the functionality of the laser tracker—ended up being used far less often for measurement tasks.
The idea of surface digitisation with a laser tracker is nothing new; an operator in 1995 could be seen dragging a reflector over the surface of an aerostructure to create a simple point cloud. But the introduction of the 6DoF tracker opened up the possibility to take this a giant leap further.
But laser tracker based large-volume scanning has accelerated over the past six years. An example is a laser scanner with extreme speed that is tracked by a laser tracker and attached to a commercial of-the-shelf robot. This scanner-tracker integration effectively turns a standard robot into a very accurate shop floor measuring machine.
This fundamental shift in measuring from physically touching a part to measure it to “just scanning it” has allowed manufacturers to completely rethink their metrology workflows and equipment.
At around the same time that 6DoF probing and scanning was changing the workflows and typical applications of laser trackers, 3D terrestrial laser scanning was beginning to find its first applications in large scale manufacturing. This high-speed LIDAR scanning technology was originally deployed for geospatial land surveying, allowing an operator to collect millions of points very quickly in the course of capturing the surface of buildings or the surrounding landscape.
On the other end of the spectrum, there are handheld scanners with an ultra large stand-off area of up to three feet with a scan line of over two feet wide that captures huge amounts of data very rapidly. Other contemporary scanners allow the operator to measure objects the size of an average car from a single station (position) in less than 30 minutes. The need to scan very large objects quickly with metrology-grade accuracies has driven different manufacturers to integrate their laser trackers to several different scanners. In addition to the hand scanners described above, there are also examples of structured light scanners located by laser tracker, as well as terrestrial laser scanners using laser trackers to control their global accuracies.
The Industrialisation of Terrestrial Measurement
Laser trackers have the inherent ability to hold very tight tolerances over very large distances. This important feature renders the marriage of laser trackers and terrestrial laser scanners as a natural progression. Terrestrial laser scanners can measure millions of points very quickly, but it can be a challenge to register these point clouds together while maintaining metrology grade accuracies. It is exactly this need that lead the industry to another advancement in laser tracker technology—a scanning absolute distance meter that pushes laser trackers into the next level of usability. A scanning ADM that measures at an internal rate of over one million points per second is now integrated in a new line of laser trackers. The technology can register submillimetre noncontact surface scans with metrology grade SMR laser tracker measurements—all within a single battery powered IP54 sensor for factory floor usage or remote outdoor applications. This new product line effectively bridges the gap between laser trackers and lidar scanners.
Looking to the Future
Manufacturing has changed dramatically since that aerospace engineer was tasked with aligning the wings to the fuselage of the 747 more than 50 years ago. The modern airplanes replacing this legendary gem require an increasing amount of data-driven processes with an even higher level of precision was achievable before. In the past, some level of misalignment in the aerostructure could simply be “trimmed out” during flight testing, but today that equates to inefficiencies of the aircraft. To reach the fuel efficiency requirements of the burgeoning aerospace industry, new inspection processes and technology must continue to advance.
I have been involved with laser trackers since the early days and witnessed the evolution of this solution as it has grown and matured at a consistent rate. It has been amazing to watch some of the smartest minds in metrology push the power and usage envelope on this technology, considering its humble roots. Today, laser trackers are utilized in almost every type of large-scale manufacturing from aerospace to power generation. The emerging trend towards noncontact scanning is pioneering another giant leap for a technology that seems to have no limits.
The global 3D scanning market was valued at US$1.007 billion in 2018, and is expected to reach US$3.26 billion by the end of 2024, at a compound annual growth rate (CAGR) of 22.2 percent from 2019 to 2024, according to Mordor Intelligence.
3D scanning technology has witnessed considerable adoption from commercial applications. Furthermore, the flexibility of the technology to be customised to meet professional needs in various industries has made it profoundly popular across major end-user industries. For instance, in the medical sector, 3D scanners are used to model body parts in three-dimensions, which is used to create prosthetics. It can also be used to facilitate wound healing and care and generate body implants.
In the current scenario, the use of 3D scanners provides dimensional quality control in the manufacturing and production of, both, small and large, critically essential, components. Whether the usage is on-site or at the point of production, it becomes vital to deliver ultra-precise, ultra-accurate, and ultra-resolution result.
However, price is one of the major factors restraining the adoption of 3D scanning solutions as the technology is still in the nascent stage in terms of global and commercial adoption.
In terms of product segment, medium rage 3D scanning is expected to hold a major market share. Phase shift 3D scanners, which capture millions of points by rotating 360 degrees while spinning a mirror that redirects the laser outward toward the object or areas to be 3D scanned, are ideal for medium range scan needs, such as large pumps, automobiles, and industrial equipment. Phase shift scanners are better suited for scanning objects with maximum distance up to 300m or less.
Meanwhile, medium-range terrestrial laser scanners, which measure point-to-point distances in spaces of 2-150m, are increasingly becoming critical for large-scale manufacturing and assembly operations’ applications, such as aircraft and ship assembly.
From a regional market perspective, the United States seen to be one of the most significant and momentous 3D scanning markets across the world, driven by the healthcare, aerospace and defence, architecture and engineering applications.
3D Scanning Landscape Remains Competitive
The 3D scanning market is fragmented. Overall, the competitive rivalry amongst existing competitors remains high. Moving forward, the new product innovation strategy of large and small companies will continue to propel the market. Some of the key players in the market are 3D Systems Inc. and Hexagon AB, and recent developments include:
April 2019: Creaform launched the third-generation scanning solution of its Go!SCAN: the Go!Scan SPARK, which is a portable 3D scanner designed for product development professionals.
February 2019: 3D Systems released a new version of Geomagic for SOLIDWORKS. With improved workflow, user interface and compatibility to various scanning device and export-import formats.
June 2018: Hexagon launched Leica RTC360, a laser scanner equipped with edge computing technology to enable fast and highly accurate creation of 3D models in the field. According to the company, it is the world’s first 3D laser scanner with automatic in-field pre-registration.
Hexagon’s Manufacturing Intelligence division has launched a laser tracker line, the Leica Absolute Tracker ATS600. This new product introduces a new concept in metrology-grade laser trackers, with targetless 3D scanning possible for the first time, directly from the laser tracker. The ATS600 can scan a surface with metrological accuracy from a distance of up to 60 metres with no need for targets, sprays, reflectors or probes.
Following in the footsteps of the Leica Absolute Scanner LAS-XL that was released in 2017, the ATS600 delivers as much accuracy as is needed by targeted metrology applications, with its focus more on measurement usability and processing speed. Previously difficult to reach areas are simply measured without even the need for tracker repositioning, while surfaces that would previously have taken hours to manually scan can now be digitised in minutes.
“We’re always very focused on usability and productivity throughout our research and development process, and so large-scale scanning is a very interesting concept for us,” said Matthias Saure, Laser Tracker Product Manager at Hexagon. “Like the LAS-XL before it, the ATS600 introduces a fundamental change to the scale in which we think about non-contact scanning. We know that users are increasingly interested in digitising parts as a way to absolutely ensure production quality, and we think the ATS600 is a product that can really take digitisation into new places of industrial production and play a key role in expanding the role of quality assurance.”
The system works by identifying a scan area within its field of view and then creating a sequentially measured grid of data points that define that surface, with accuracy to within as little as 300 microns. Measurement point density is fully customisable, so that users can choose the ideal balance between detail and process speed for their specific application. The Leica Absolute Tracker ATS600 is unique in delivering this functionality at metrology-grade accuracy and alongside easy integration within established metrology workflows – the ATS600 is compatible with all major metrology software platforms as has been designed to sit comfortably within a wider metrology toolkit.