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As Accurate as Needed: Stepping Away from the Accuracy Race

by Duncan Redgewell on February 19, 2019 From Thought Leader, Technology

When it comes to measurement technology, it can be very easy to get caught up in the race to deliver ever finer degrees of accuracy. And while it’s true that increased accuracy is in many cases useful, focusing on this single aspect of a metrology system isn’t always the most productive way to face the challenges of a measurement application.

Accurate-as-needed-2Engaged metrologists are by now well aware that accuracy is just one among a number of factors that should influence their technology investment decisions, with factors from handling and portability to workflow and process speed often just as, if not more, important.

This is a perspective that has been increasingly occupying us here at Hexagon Manufacturing Intelligence, and the idea of delivering appropriate accuracy instead of maximum accuracy has guided product development decisions in a number of areas in recent years. 

We’re not giving up on the importance of accuracy, as you can tell by the fact that Hexagon products continue to be among the market leaders in terms of accuracy. We’re just making sure we pay enough attention to the other elements that are such a vital part of turning high-end technology into better tools.

A clear example of this approach can be found within our range of handheld 3D laser scanners.

The Leica Absolute Scanner LAS-XL: Laser Scanning on a Whole New Scale 

The Leica Absolute Scanner LAS has been a part of our product line up since 2016. Over the past few years it has impressed customers around the world with the measurement speed and versatility delivered by its ‘flying dot’ scanning technology, and its accuracy, which clocks in at within 50 microns under typical conditions.

Accurate-as-needed-3Building on the success of this product was a priority for the Laser Tracker product line that brought it to market. When asking how current users would to like to see the LAS improved, the team got some interesting answers. More productivity, with better usability and faster measurement process times were increasingly preferred improvements – what they were hearing far less often were requests to squeeze a few more microns of accuracy out of the technology.

Such feedback has surfaced in parallel with an increasing appetite from users to transport metrology-grade analysis into entirely new measurement arenas. This might include measurement of extremely large surfaces like those found on wind power blades or aerospace fuselage sections, or parts in areas that are hard to reach with existing tools. And it is typically in applications where micron-level accuracy isn’t vital.

And so was born the idea to develop the Leica Absolute Scanner LAS-XL. Based on the same ‘flying dot’ technology as the LAS, the innovation behind the LAS-XL was the refining of the technology to increase the area being scanned with every pass of the scanner. Our engineers were able to produce a system that can operate with a working measurement distance – the distance between the laser scanner and measurement object – of up to 1000 millimetres, up from the just 300 millimetres offered by the LAS. This has the corresponding effect of increasing the maximum width of the system’s laser scan line from 220 to 600 millimetres.

Accurate-as-needed-4This change brought a new scale to the world of laser scanning. With the LAS-XL, a surface requiring half a day of difficult scan work can now be digitised in half an hour. It’s clearly a product with huge potential to boost productivity by turning the real world into 3D data faster than the vast majority of metrology tools currently available.

Of course, such sea change improvements don’t come for free, and the trade-off at the centre of the LAS-XL proposition brings us back to the accuracy arms race: while the LAS offers accuracy to within 50 microns, with the LAS-XL accuracy is to within 150 microns. That’s obviously a key trade-off, and it’s one which is worth it for some users but not for others.

So what does this mean for accuracy in the world of metrology? The answer is nothing; high-accuracy measurement tools aren’t going anywhere. In fact, many of the customers who invested in an LAS-XL over the last year chose to invest in an LAS at the same time – a pair of complementary products that can cover the needs of a wide range of applications without compromising on speed or accuracy.

But the LAS-XL does show that there is room for a little something in the production spaces that the metrology world hasn’t been paying enough attention to – something that’s not as accurate as possible, but as accurate as needed.

To find out more, visit the Leica Absolute Scanner LAS-XL webpage. 

Duncan Redgewell

Duncan Redgewell is Vice President Portable Products at Hexagon Manufacturing Intelligence. Having spent 30 years in the industry, Duncan has led Hexagon’s laser tracker business since 2006 and for the past 10 years has taken responsibility for the ongoing growth and business development of all portable metrology products at Hexagon.