The utility of dense scan data for metrology is proving itself in multiple applications
The development of laser scanners and structured white light scanners for metrology is proceeding down two parallel tracks. Makers of such devices come up with advancements. Meanwhile, customers seek improvements. The two tracks sometimes converge.
“That’s why we put so much work into the development of new scanning technologies,” said Joel Martin, director of portable metrology, North America, for Hexagon’s Manufacturing Intelligence division, North Kingstown, R. I. Scanners now can perform tasks “that laser line scanners could never do, even quite frankly two or three years ago, let along five, six, seven years ago,” he said. Scanners had “required some level of expertise to be able to use. And that’s because you needed to understand the power of the laser and how much exposure was on the camera chip.”
Now, “There are huge improvements in the automation of 3D scanning,” said Guillaume Bull, product manager at Creaform USA, Lévis, Québec, Canada. “This includes the development of turnkey automated solutions like the Cube-R, but also improvement on the software side with the development of digital twin environment software modules.”
One area of improvement is scanning reflective surfaces.
“The laser technology is inherently better at coping with reflective surfaces than, let’s say, projected light systems,” said Toon Peeters, business development engineer at GOM Americas Inc., Charlotte, N.C., part of the ZEISS Group. GOM makes both structured white light scanners and laser scanners. “Combining this with powerful software makes it able to scan pretty reflective surfaces with minimal noise influence.”
Scanners also are coping with new materials. “The biggest improvements to the technology have been to the handling of challenging materials,” said Matthew Gibbons, sales applications engineer manager for Nikon Metrology, Brighton, Mich. “The combination of Nikon optics and the latest algorithms help us to produce low noise/high resolution scans on a variety of difficult-to-scan surfaces. We’re able to produce a high-quality laser line that filters out spoiler data normally collected from dark, glossy or machined surfaces.”
Improvements in scanning technology include speed and how much can be scanned at once. About five years ago, “it was slow,” said Martin of Hexagon. “Maybe sometimes 10, 12, 15, 30 lines per second was the maximum speed of some of the really early-generation scanners. Today, we’re up north of 300 lines per second. The raw speed of the scanner itself is huge.”
Another aspect, he said, “is field of view, or scalable range of the scanner. One of the analogies I try to use is it’s like painting a house. [The size of the] paintbrush you use to paint with is similar to how big your scan line is relative (to) how fast it’s going to go. Some of the early scanners had one, maybe two-inch lines. That would be like painting your house with a one-inch paintbrush.”
There have been other improvements. “If we’re talking about hand-held scanners, the ability to go to the part or job to measure instead of having to move the part to the metrology room [is important],” said Peeters of GOM. Scanning, he said, is being used for castings, including “large and small parts as well as the molds, sand scores, and assemblies.”
Scanners also assist with boosting productivity. “The challenge in today’s global manufacturing industry is that it must deal with more complex parts and assembly designs than ever before,” said Bull of Creaform. The use of traditional CMMs often creates bottlenecks in the manufacturing process and companies must often operate with a lack of skilled resources and limited working time.
3D scanners “acquire an immense quality of data in little time,” Bull added. “This enables a better understanding of complex shaped parts than traditional probing methods can provide. That really helps when trying to understand what is wrong with a part. 3D scanning solutions simplify and speed up the analysis process.
“3D scanners are very fast compared to traditional CMM,” Bull continued. “Even where they are not as accurate, they help to reduce the workload of the CMM by performing most of the measurements and leaving only the critical measurements to the CMM. This reduces the bottleneck on the CMM—for a fraction of the price.”
Many of the improvements in scanning technology stem from customer needs. “This has been driven by the market,” said Hexagon’s Martin. “The market has said, ‘We want to scan—we don’t want to probe all these holes. We want to scan this [part with all of these holes]. It’s faster, it’s easier, it’s more efficient.’
“But the scanners, the technology, were the limiting factor five years ago,” Martin continued. “Today, the scanners have actually caught up to, and in some cases exceeded, what the market requirements have been as far as being able to implement the technology. The question is not so much, ‘Well what can we now finally do?’ It’s ‘what can the scanners finally do that the market has been pushing them to do for the last five years?’”
Martin likens customer demand to three pillars—speed and volume; resolution or quality of data; and ease of use. “This is what people have been driving us towards,” he said. “If I had to bring it to the most narrow scope, I would say the biggest one would be ease of use.” For example, Martin said if a shop only has one person who can operate a scanner, “you no longer have a usable piece of equipment” when that person goes on vacation.
“We’ve put a tremendous amount of development and energy into the ease of use of the product, really making it so that, if you had five operators in the shop, all five of them could pick up the scanner.”
Customers also seek a combination of speed and accuracy.
“The primary features that customers look for are speed and accuracy,” said Gibbons of Nikon Metrology. “Customers are looking to get the most accurate and complete results as quickly as possible. Traditionally, probing only can be a time-consuming method of measurement. Each additional item to be inspected can add to the cycle time. Laser scanners cover a wider area in one pass and could potentially provide data for multiple measurements. Increasing the number of features to be extracted oftentimes won’t add to the length of an inspection.”
CMMs are accurate tools, so customers are expecting other 3D technologies to achieve similar accuracy, according to Bull of Creaform. “Even though today’s 3D scanners are not as accurate as a standard bridge CMM, they are getting closer with the new generation of scanners.” Scanners “have achieved enough accuracy to be used for metrology in quality control and quality assurance.” Peeters of GOM said other customer considerations include scanners that are portable and can deal with a “large scale of parts, small and large.”
So where is scanning for metrology headed? Peeters of GOM expects that fewer reference points for structured light systems will be needed, with “even faster data capture.” Also, he predicted scanning will be “operated by tablet or remote.”
Bull of Creaform said scanners will become even faster and more accurate. “This will evolve directly with the improvement in computer speeds and optical components,” Bull said. “But where I see the next big improvement is more in how the scanner data will be used. Right now, manufacturing companies use 3D scanners and CMMs to access the quality of built parts. They measure parts and check if they are compliant with the design requirements. I see a future where 3D scanners will instead be used directly on the assembly line to measure the parts as they are built.” That would mean analyzing information “and making adjustments on the assembly line right away.”
Gibbons of Nikon Metrology has similar expectations. “Scanners will continue to get faster and move closer to production,” he said. “The goal of most manufacturers is to insert quality earlier in the manufacturing process. Waiting until a part reaches a quality lab results in lost time when it comes to reacting to possible issues. Shortening the time for results can mean major time and money savings.”
Making scanners even easier to use is another priority. Hexagon’s Martin said his company uses a technology called SHINE, or Systematic High-Intelligence Noise Elimination, in its scanners “that allows us to just pull the trigger, collect data. It doesn’t matter if it’s a black part, it’s a white part, [or if] it’s chrome part.”
SHINE, he said, “allows you to scan directly across multiple materials. And I expect to see that more and more.” What’s more, he said, scanners will be called upon to deal with more materials and to keep getting better. “Today, laser scanners can’t scan glass because they penetrate. Hopefully, we’ll come up with a solution to that. What was high accuracy five or six years ago is no longer high accuracy today,” he added. “That benchmark continues to move on us. We will see greater ease of use, greater quality of data, and higher accuracies. And probably, as I said, new material types will start to pop up and people will want to get scan data on them as well.”
Customers will continue to expect more, Martin said. Companies must be “absolutely tied into the voice of the customer, absolutely understand what our customers are looking to do,” he said. “And not even just today—looking at where their problems are going to be five years from now.”