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Next Generation Laser Based Measurement and Inspection Tools

How Lasers Are Revolutionizing Gun Bore Measurements How Evolving Gun Technologies are Creating a Pressure to Change How Lasers Rate Against Conventional Measurement Methods Finding a Place for Lasers Laser Based Gauges: What Does the Future Hold? Sponsored by

Published by Global Business Media



Next Generation Laser Based Measurement and Inspection Tools

Contents Foreword


Tom Cropper, Editor How Lasers Are Revolutionizing Gun Bore Measurements How Evolving Gun Technologies are Creating a Pressure to Change How Lasers Rate Against Conventional Measurement Methods Finding a Place for Lasers Laser Based Gauges: What Does the Future Hold?

How Lasers Are Revolutionizing Gun Bore Measurements


Laser Techniques Company LLC

The Challenge

Sponsored by

Published by Global Business Media

Published by Global Business Media Global Business Media Limited 62 The Street Ashtead Surrey KT21 1AT United Kingdom Switchboard: +44 (0)1737 850 939 Fax: +44 (0)1737 851 952 Email: Website: Publisher Kevin Bell Business Development Director Marie-Anne Brooks Editor Tom Cropper Senior Project Manager Steve Banks Advertising Executives Michael McCarthy Abigail Coombes Production Manager Paul Davies

Laser Based Inspection Industry Adoption A Broad Range of Applications Pushing the Envelope

How Evolving Gun Technologies are Creating a Pressure to Change


Tom Cropper, Editor

History of Development Existing Techniques Into the Future

How Lasers Rate Against Conventional Measurement Methods


Jo Roth, Staff Writer

Air Gauges Star Gauges Video Imaging Borescopes Laser Based Technology

For further information visit:

Finding a Place for Lasers

The opinions and views expressed in the editorial content in this publication are those of the authors alone and do not necessarily represent the views of any organisation with which they may be associated.

Development of Laser Technology

Material in advertisements and promotional features may be considered to represent the views of the advertisers and promoters. The views and opinions expressed in this publication do not necessarily express the views of the Publishers or the Editor. While every care has been taken in the preparation of this publication, neither the Publishers nor the Editor are responsible for such opinions and views or for any inaccuracies in the articles.

Software and Analysis


James Butler, Staff Writer

Energy Market Aerospace Industries

Laser Based Gauges: What Does the Future Hold?


Tom Cropper, Editor

Mechanical Gauges Borescopes Lasers and the Future

Š 2014. The entire contents of this publication are protected by copyright. Full details are available from the Publishers. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical photocopying, recording or otherwise, without the prior permission of the copyright owner.

Space, Above and Beyond

References 15



Foreword I

T’S ENCOURAGING when you see a

lead to deformation of the surface and renewed

technology which was developed in the middle

blemishes. Borescopes require no contact,

of one century still being used as the next century

but, in turn, rely on the training and subjectivity of

enters its teens. Air gauges were first used

the operator.

around 60 years ago and ever since then have

As we’ll see in the first article of this report, laser

been a crucial component in bore inspection

technology has addressed all those concerns.

and measurement. Such longevity says a great

Moreover it has successfully revolutionized the

deal for the technology itself, but everything has

industry, producing more accurate and reliable

a natural lifespan and air gauges are beginning

data, which can be monitored more effectively.

to look somewhat out of date for the modern age.

Elsewhere in this report we’ll look more closely

More recently, advances have been made with

at the driving need for change, as technology has

non-contact video borescopes, but it’s with lasers

developed to become increasingly sophisticated.

that the real interest for the future lies.

We’ll see how this development has exposed the

In 2001 Laser Techniques started out with the

problems and deficiencies in current inspection

aim of demonstrating how laser technology could

methods and what more can be done to address

dramatically improve the way in which bores, tubing

them. Finally, we’ll cast an eye to the future and ask

or piping were measured. Traditional technologies

how lasers can further improve over the coming

had served their purpose for decades but the

years and whether it really is the end of the line for

technology they were measuring was evolving apace

traditional gauging methods.

and setting new requirements in terms of accuracy and reliability, which they could no longer meet. For example, a traditional air gauge requires contact with the bore surface which in turn can

Tom Cropper Editor

Tom Cropper has produced articles and reports on various aspects of global business over the past 15 years. He has also worked as a copywriter for some of the largest corporations in the world, including ING, KPMG and the World Wildlife Fund.



How Lasers Are Revolutionizing Gun Bore Measurements Laser Techniques Company LLC

Developments in laser based inspection are having revolutionary implications for gun bore measurements.


HAT DO rocket thrusters, nuclear steam generators and high performance gun barrels have in common? They can all be fiendishly difficult to inspect, they’re all associated with demanding performance specifications and high value operations; and if something goes wrong in the field, the results can be catastrophic. Unfortunately, many of the methods used in testing gun barrels date from the 1940s. They rely on operator experience and skill, which means that test results can be inconsistent, inaccurate and unreliable. In recent years significant improvements have been achieved using laser-based measurement and inspection technology in aerospace, nuclear power generation and a variety of defence applications. Increasingly, these same technologies are now being used for high performance gun barrels, and are demonstrating valuable improvements over outdated mechanical gauges and manually operated borescopes.

The Challenge For the past several years, the technology behind modern weapons has evolved to a high level. Aggressive propellants, high internal pressures and ever-increasing demands for performance and accuracy require equally demanding measurement and inspection criteria. To achieve optimal performance, rifle barrels and cannon tubes rely on a precise mechanical fit of the projectile within the bore. Over time, the bore erodes and as it does, velocity and accuracy are also reduced. Ensuring that rifle barrels and gun tubes are manufactured to high tolerances is crucial to the weapon’s operation. Unfortunately, while the metrology and manufacturing technology employed in the production of gun tubes

has made huge advances, the underlying technology for most conventional measurement and inspections systems has not changed in over 50 years. Manually operated mechanical gauges are used to measure the bore diameter at specific locations along the length of a gun tube. They are also used to measure the depth of the lands or grooves, but this leaves plenty of scope for inaccuracies. When a gauge records simple diameter measurements, features such as tool chatter, non-concentric lands and grooves and local tool gouging may go undetected. Furthermore, measurements acquired by hand rely completely on the experience of the operators, which can lead to inconsistency in measurement and testing results. Adding to the difficulty, odd-numbered lands and grooves, like those found in many sniper weapons and medium calibre gun barrels, make consistent diameter measurements nearly impossible. Air gauges are also used by many organisations. However, these tools have extremely limited range of operation and cannot map the entirety of the bore.

Laser Based Inspection Because of the limitations and inconsistencies associated with traditional gauging methods, there is a growing interest in the transformative results that are attainable through laser based measurement and inspection methods. These can be used at all stages of the lifecycle from manufacturing quality control to depot level maintenance and bore erosion measurement during field testing of aging equipment. The basic operation of the laser inspection system is relatively straightforward. A tiny laser beam with a spot size of roughly 0.05mm (0.002 inches) in diameter is projected onto the internal surface of the gun bore. An WWW.DEFENCEINDUSTRYREPORTS.COM | 3


While the metrology and manufacturing technology employed in the production of gun tubes has made huge advances, the underlying technology for most conventional measurement and inspections systems has not changed in over 50 years

optical receiving unit images the reflected light onto a photodetector, which then precisely calculates the distance to the gun tube surface. The sensor head rapidly rotates as it is drawn through the length of the gun bore, thus creating a high-resolution, three-dimensional data cloud that can accurately depict the internal geometry of the test article. The results can be used to optimise the manufacturing process, predict the remaining life span of the barrel or locate potentially dangerous flaws. When the inspection system does detect a flaw it can generate a report which provides the precise location and magnitude of the defect. It can also create reports that characterize everything from basic “go/no-go” criteria, to a full statistical analysis of the internal structure of the bore. Laser-based scanning systems can also generate visual images that are similar, but in many ways superior to those of manuallyoperated borescopes. Firstly, laser-video images can be generated much more rapidly than those obtained by manual recordings of borescope inspections. In addition, the results are typically accurate to within a fraction of a millimetre. Borescopes can be susceptible to optical distortion, shadowing and glinting, which can greatly hinder the manual inspection process. Finally, borescopes cannot capture and display the entire bore surface in one image. Laserbased bore mapping systems can present the entire bore – effectively sliced and laid out in plan-view. This allows the operator to scroll over, pan and “zoom in” on features quickly and efficiently.

defence industry. Initially, leading research and development organisations and test centres expressed a need for better measurement and inspection technology. This has been followed by military end users, as well as civilian manufacturers of highperformance weapons. One of the leading names in this field is Laser Techniques Company, LLC (LTC), which has dedicated more than ten years of effort, working with the US Army Research Laboratories, US Army Yuma Proving Ground and others to develop a number of laser-based gun tube inspection systems. The company began with a system for automatically mapping the bore of M2 – 50 calibre gun tubes and has since developed a family of systems that cover most NATO calibres, ranging from 5.56mm carbines up to 155mm howitzers. The result of all this research and development is LTC’s trademarked BEMIS™ laser bore mapping system. It provides superior results to conventional mechanical gauges and camera-based systems, and exhibits larger measurement ranges than air gauges and mechanical “star” gauges. Test results can be displayed in a variety of graphical or tabular formats. It can generate both 3D maps of the inside of a gun tube, as well as high-resolution camera-like LaserVideo™ images that reveal an unprecedented level of clarity. Examples of the images it can produce can be seen in Figures 1 and 2.

Industry Adoption

•S  mall Calibre Inspection Sensors: Designed to inspect 5.56mm to .50 calibre rifle barrels, as well as 9mm through

Laser based inspection technology is now becoming widely used throughout the



A Broad Range of Applications The BEMIS™ system can be employed within a range of sizes including:



.45 calibre hand gun barrels. The sensor delivery system employs a precisely controlled vertical or horizontal stage. •M  edium Calibre Inspection Sensors: Designed to inspect 20mm to 76mm diameter gun barrels. The sensor may be delivered using either a rigid horizontal delivery system or a portable probe pusher, which is mounted to the muzzle of the gun barrel. In the portable configuration, the sensor is delivered through the barrel using a flexible stainless steel drive cable. Rigid delivery systems, which use a shaft equal to the length of the barrel, are typically used in labs and

R&D facilities in order to perform coating analysis and/or long-term erosion and wear studies. •L  arge Calibre Inspection Sensors: Designed to inspect 105mm through 155mm gun tubes for tanks and artillery weapon systems. The sensor is typically delivered using a self-propelled sensor delivery unit commonly referred to as a “crawler”, which pushes the sensor throughout the length of the gun tube. Portable systems are typically used by field units or organisations that must travel with the test article and perform inspections on-site.




Laser-based scanning systems can also generate visual images that are similar, but in many ways superior to those of manuallyoperated borescopes


• Mortar Inspection Systems: Designed for 60mm, 81mm and 120mm mortars. The sensor is either delivered using a horizontal or vertical stand, which is mounted to a rigid shaft. Eddy Current sensors may also be employed to detect sub-surface cracks in non-ferrous metals, such as Inconel. •S  pecial Applications: LTC works with both civilian and governmental organisations to adapt its BEMISTM technology to unique and unconventional applications.

Pushing the Envelope Over the past few years, manufacturers have also been expressing interest in using this technology for quality control during the manufacturing process. In order to provide superior results as compared to conventional mechanical and air-gauges systems, the BEMIS™ would have to generate results to better than +/- 0.0005 inch, a daunting challenge. However, in March of 2014, LTC delivered a 155mm Utra-High Resolution (UHR) bore mapping system to the US Army Yuma Proving Ground. Extensive laboratory tests validated the fact that the 155 UHR actually exceeded their stated performance goal. The engineering team at LTC has recently extended the UHR capability to small


calibre weapons. It has been recently reported that a first-generation 7.62mm UHR sensor has achieved repeatable measurements in the range of +/- 0.0002 inch, an astonishing accomplishment. The BEMIS™ system, developed by Laser Techniques Company, is a shining example of the significant advantages new technology can bring to both manufacturers and end users of high performance gun tubes. While mechanical gauges and borescopes will always have their place, laser inspection systems, such as those created by LTC, deliver significant benefits in terms of accuracy and reliability. The technology is already in use and is rapidly gaining a reputation as a crucial piece of technology that will improve manufacturing efficiency and product quality while also lowering the long term cost of quality control and testing.

Contact Laser Techniques Company LLC. 11431 Willows Road NE, Suite 100 Redmond WA, 98052, USA Tel. +1 425 885 0607 Fax. +1 425 885 0802 Web:


How Evolving Gun Technologies are Creating a Pressure to Change Tom Cropper, Editor

A new era of innovation in measurement and gauges has the potential to increase significantly gun bore performance.


OR CENTURIES the trend in gun design and performance has been for increased range, power and rate of fire. However, the biggest barrier to improvement has been the barrel itself. Wear and erosion limit performance while even the tiniest of deficiencies will have severe implications for its accuracy. Measuring the surface of gun bores enables manufacturers to ensure new models are delivered with the best possible specifications and that problems with older models can be identified and rectified in a more efficient and timely manner. Until recently though, measurement technologies and techniques have remained relatively unchanged, but now a new age of innovation is raising the bar on gun bore measurement and inspection.

History of Development While it may seem strange in an article about the future, it can be instructive to look back to the past. In the 10th century AD Chinese armies first began using weapons known as fire-lances, which used gunpowder to spit flame and shrapnel at the enemy. It was the earliest ancestor of the gun, which for centuries has been the centre of warfare. From the moment when cannons became common during the middle ages, there has been a continual battle between attack and defence. First of all the firepower of cannons rendered existing walls and defences obsolete. Then defenders developed so-called star forts designed to withstand artillery. This in turn sparked the creation of armour piercing rounds and so the battle continued to the present day. At the same time, technology resulted in guns becoming smaller and more powerful with the arrival of early hand canons and rifles. The difference between these early forebears and the firearms we see today is extreme. Early muskets, for example, were only accurate to

around 100 yards, while bullets were much smaller than the barrel to account for the accumulation of soot. Predictably, this had a negative impact on accuracy. It’s far removed from the smooth fit, accurate and long range weapons we have today. These weapons are capable of delivering pinpoint accuracy, and thousands of rounds per minute. However, that in itself brings problems. The high fire rate found in modern state-of- the-art weaponry has a devastating impact on the gun bore interior. Heat, friction and corrosion join together to degrade rapidly the surface of the gun bore. New materials and technologies are being introduced to protect the surface of gun bores, such as replacing chrome linings with a plasma alloy1. These have the potential to improve the resistance of the gun bore and increase the life expectancy of equipment. However, what is equally important is that inspection methods improve to provide increased information at the time of manufacture and for ongoing maintenance and repair. The problem is that many existing inspection technologies and techniques have changed little over the years. Existing Techniques The most common ways to inspect gun bores revolve around star and air gauges. Air gauging has been in use for around 60 years. It uses a precision plug with a few ten thousandths of an inch clearance. Behind this is a highly regulated air pump which forces air through. As it goes through the plug it can escape through tiny holes and grooves in the surface of the bore. By measuring the pressure to a highly precise degree, it is possible to monitor any variations, and therefore spot inconsistencies. The pressure readings can show up on a device which looks like a thermometer and is calibrated to measure to within a fraction of an inch. WWW.DEFENCEINDUSTRYREPORTS.COM | 7


These systems also

This has spurred the search for advanced technologies that push the bar higher, deliver greater levels of automation and, as such, superior consistency.

have their deficiencies

Into the Future

which have become increasingly obvious as technology improves This method has been useful for identifying inconsistencies and wear in the bore tubing. However, where it falls down is in measuring the roundness of the tube. For this, star gauges can be used. They employ small balls which protrude from the side providing multi point measuring specifications. They measure the same tolerances as air gauges, but can check for any out of round properties. Even today, decades after they were first developed, these remain the standard form of measurement. To say a product has been air gauged is often seen as indicating that a product has attained a certain level of quality. However, all it really means, in many cases, is that the bore has been measured – not necessarily improved. These systems also have their deficiencies which have become increasingly obvious as technology improves. They are mechanical devices and as such their accuracy levels are not always sufficient. Equally, they are inconsistent. Operating such a device requires a skilled hand and plenty of experience. Also, the final results are often subject to interpretation by the operator. What’s needed is a higher degree of accuracy and consistency.


The latest trends push beyond mechanical gauges, and move towards digital and automated monitoring solutions. High definition camera probes can be used to scan the interior of gun tubing. They can produce highly detailed and magnified images which can map accurately the interior of a gun bore. These can be used both to test new products and for ongoing maintenance and inspection allowing operators to chart wear and tear accurately. A further innovation comes in the form of laser technology. This can swiftly map the interior of a gun bore to an unprecedented degree of accuracy, producing instant maps of the surface. This data can be displayed through a 3D chart and analysed through state of the art software which produces automated reports. This delivers a much greater level of accuracy and also removes inconsistencies and operator subjectivity from the process. Laser inspection tools such as these have been in development for many years. They have already delivered great improvements, but there is potential for much more. This technology is still in its relative infancy so there is more to come, both in the capabilities of the system and also in the cost effectiveness. For now, mechanical gauges will still have a place for more basic measurement requirements. But these state-of-the-art tools are now arriving into the market to deliver the level of accuracy and reliability that the latest modern weaponry requires.


How Lasers Rate Against Conventional Measurement Methods Jo Roth, Staff Writer

Mechanical gauges have been in use for 60 years, so why does the industry need to change?


T IS now more than 60 years since a Sheffield company first began developing mechanical air gauges, and since that time they have remained the standard measurement tool in many industries. Whenever something has worked so well for so long there is a natural reluctance to change. Any evolution of technology brings risks and an associated cost. Therefore, the question the industry needs to ask is: are the benefits real, and are they worth the additional investment required? This article will look at the various types of measurement and inspection tools and assess their strengths and weaknesses.

the defence industry. However, the development of highly advanced, rapid fire weaponry means the results are increasingly not fit for purpose. Using mechanical gauges is a long process. It can take hours and produce relatively little information. They require skill to use and the results can be open to interpretation based on the opinion of the operator. Most of all, like air gauges, they require contact and can, in turn, add defects or deformation to the interior of the bore. This is why, after the eighties, manufacturers began looking for non-contact forms of inspection, such as borescopes.

Air Gauges

Using cameras to map the interior of a bore can facilitate the inspection of hard to reach areas. High quality cameras can produce pin sharp, magnified high definition images of the interior of the bore tubing. These in turn can be visually inspected by an operator who will be able to identify any defects or grooving. HD and LED technology allows these devices to produce clearer images than ever, that can then be fed wirelessly to a monitor, which in turn produces the reports. It possesses a clear advantage over mechanical gauges in that it requires little or no contact with the bore itself. However, it still relies on the human element – namely an operator who will need to scan the images checking for defects. Results depend on his or her expertise and can be further affected by lighting or shading, which can cause it to be challenging to make accurate assessments.

The operation of an air gauge is relatively straightforward. A plug is inserted into the bore which has a clearance of a fraction of an inch either side. Air can be pumped into the bore which passes through this tiny gap either side of the plug. The pressure at the plug can be measured using a highly precise device – any fluctuation will denote the existence of a flaw in the surface. It is a simple to use device and with adequate training an operator can detect wear and erosion in the bore surface. However, it has significant failings. While it is useful for detecting grooves and blemishes, it is not useful at detecting any deflection in the roundness of a gun bore. For this, so called ‘star gauges’ are required.

Star Gauges A star gauge is a multi-point sensor device which uses small balls to extend from the main plug to the side of the gun bore. This measures the surface and can detect all the defects that an air gauge can show. In addition, it will be able to measure the straightness of the barrel. For years this was the staple measurement tool for

Video Imaging Borescopes

Laser Based Technology Removing the human element is the next stage of the evolutionary process, which is why operators are looking for automated technologies and processes that produce far more accurate and consistent results. One of the most WWW.DEFENCEINDUSTRYREPORTS.COM | 9


Lasers, however, represent a significantly improved method to deliver increased accuracy and eliminate contact and human subjectivity from the process

promising technologies comes with laser based measurement and inspection solutions. Although a new groundbreaking technology, it uses principals of optical triangulation which were first pioneered by the Ancient Greeks. Euclidian geometry can calculate the third side of a triangle if the lengths of the other two are given. The method involves a small laser dot of 0.05 to 0.02 inches being projected onto the surface of the gun bore. The probe rotates as it is drawn through the barrel and by sampling the signal generated thousands of times per revolution, a detailed map of the tube’s inner surface can be created. This can be used to generate accurate reports about the life expectancy and wear and tear on the inside of bore. It can obviously be used to detect defects on old mechanical parts, but ultra-accurate versions are also increasingly being used for go/no go testing of new products. One of the leading manufacturers in this space is Laser Techniques Company (‘LTC’) and they say that their laser technology has a higher measurement range than traditional air or star gauges, as well as providing a non-contact form of measurement, which eliminates friction and further damage. They have advantages over video imaging because they are less susceptible to problems with shadowing. Instead results can be rendered either graphically or in a 3D map, which renders the surface of the gun bore to an unprecedented level of accuracy. Finally, this automated process removes the danger of human error or subjectivity inherent in all the other methods discussed here.


However, lasers are not going to form a catchall replacement. Mechanical gauges and video imaging all have their place, with new models being developed and introduced to the market all the time. The additional cost of lasers will mean individuals and some organizations will continue to use this option despite the benefits provided by laser-based inspection systems. However, commercial and governmental entities are embracing lasers increasingly as representing the next evolutionary step which can deliver results for the highly sophisticated and demanding requirements of modern design. In the end, the pros and cons of each of these systems need to be weighed against each other. Lasers, however, represent a significantly improved method to deliver increased accuracy and eliminate contact and human subjectivity from the process. As a result it is here that the majority of research and development efforts for the next generation of cutting edge technology is being focused.


Finding a Place for Lasers James Butler, Staff Writer

Laser inspection tools offer a huge range of possibilities. This article explores some of the ways in which they are being used around the world.


ASER INSPECTION tools represent the latest ‘must have’ development for the industry. The ability to provide accurate, non-contact surface mapping represents a cosmic leap forward from established mechanical gauges. However, as with any new technology, the potential benefits can only be realised if it is used in the right way. Commercial organisations in sectors such as the defence, aerospace and energy industries are turning to lasers as a way of delivering the required increase in performance in their inspection and measurement tools. However, in each of these areas they come up against a range of challenges all of which require a bespoke and flexible solution.

Development of Laser Technology The basic operation is relatively straightforward. A probe can project a tiny laser dot onto a surface which rotates as it is drawn through the tubing. It is able to detect thousands of signals per rotation and the result is a highly detailed map of the interior of a tube, noting any defects, wear or erosion. It can be used both during the manufacturing stage and also in testing and maintenance of older equipment. This technology may appear to represent the cutting edge of what’s possible, but it’s actually been around for many years. LTC, a pioneer in this field, was founded in 2001 with the aim of showing that laser technology could provide real improvements in an industry which had used the same inspection tools for decades. The result is their industry leading BEMISTM technology2. Its laser profiling sensors are drawn through pipes or bores by a crawler delivering a significantly wider range of measurements in a faster time than mechanical gauges or borescopes. Its most common use is in the defence industry, where it is being used to inspect new products as they leave the factory, estimate life cycle or provide ongoing inspection for maintenance. One example is a partnership with Chesapeake Testing where it will offer the BEMIS-SC™ product for

small calibre weapons. However they do intend to offer testing for larger calibres in the future. “We have always focused on building our company around very unique technologies,” said Jim Foulk of Chesapeake Testing. “BEMIS™ has changed the industry in regards to the inspection of weapon systems.”3

Energy Market As well as the defence industry, they also have some potential in the energy sector. Upstream Pumping Solutions recently investigated the potential for lasers in measuring stators for Progressive Cavity Pumps (PCP) and Positive Displacement Motors (PDMs)4. Currently these are normally inspected by optical borescopes, but the process brings a considerable number of challenges. In any situation the results obtained by a borescope are reliant, to some degree, on the experience and expertise of the person who is operating the equipment. However, in this instance the problems are more severe. The inside surface of PCP and PDM stators is black and shiny. The interior is dark and prone to problems of shading, all of which can skew the observations of the operator. In addition, the aspect between major and minor diameters may present a number of challenges. Finally, any contact made with the interior has the potential to cause further deformities which means piping can be damaged by the actual inspection process. Theoretically, lasers can provide an answer to this problem. They are non-contact, which means no damage, and can produce reliable data regardless of the lighting environment within the stator. There is no reliance on operator skill or expertise, but instead an automated quantitative set of data.

Aerospace Industries Laser technology has also long been a part of the aerospace industry. NASA first used it on thrusters for the space shuttle project where perfect accuracy was a matter of life and death. Today the Shuttle may be no more, but lasers continue to play an important role. WWW.DEFENCEINDUSTRYREPORTS.COM | 11


Aside from the sensor equipment, a key element for any system is the back-up software it uses

Aside from NASA, they are also used to detect cracks and other defects in aircraft. Here application is a problem as high diameter to length ratios make it extremely difficult for other detection methods to function properly. The solution is to use a fluorescent penetrant inspection method. With this, a fluorescent penetrant is applied to the surface which the operator can then scan with a Laser-Scanned Penetrant Inspection (LSPI) sensor. It has been used to identify and scan correctly even the smallest cracks and defects.5

Software and Analysis Aside from the sensor equipment, a key element for any system is the back-up software it uses. Laser based measurement devices can produce a massively increased amount of data in a shorter time and with less manpower than conventional systems. How this is displayed is crucial to the overall offering. As such LTC’s products allow operators so see


rapid real time results in a variety of formats including 3D mapping, magnified images, or in graphical form. An example of how advanced this is becoming can be seen with the development of LTC’s add-on LaserViewer 3DTM technology package. This allows the operators to more easily view three dimensional data sets. Images can be displayed in flat or cylindrical form, rotated, magnified or tilted. It provides the most vivid map yet of the bore interior. Laser technology has been used for around ten years now, and in all that time the range of applications to which it can be applied has increased. Much of this has been demand led with end users coming to manufacturers with a problem for which they develop a prototype. This technology is reinventing itself all the time which is why it’s so interesting to look into the future and think about where these innovations are going. That’s what we intend to do in the final article of this report.


Laser Based Gauges: What Does the Future Hold? Tom Cropper, Editor

Laser based technology has already expanded the horizon of what’s possible. However, further development is likely to come in the coming years.


HE LESSON to take from the articles in this Report so far would appear to be clear: mechanical gauges are antiquated, borescopes are limited and the future lies with laser based inspection systems. However, the truth is more nuanced than that and new technological innovations are being introduced in all these areas. Manufacturers are adapting decades old air gauge technology for the modern market, while borescopes are making use of the latest HD capabilities to expand continually the boundaries of what these devices can achieve. The cutting edge of development, though, undoubtedly lies in the realm of laser based technology. Already it has succeeded in transforming the landscape, and with new research being conducted into the next generation of products, it is clearly only beginning to explore what is possible. This article will examine what the future holds for these very different types of measurement devices.

Mechanical Gauges Given the advances in modern weaponry, it is perhaps surprising that air and star gauges have remained so important for so long. However, air gauging is still used and manufacturers are adapting the technology to address some of its major flaws. In particular, new products are looking to minimize the amount of contact they have with the part to be measured. One approach is to use air to electric gauging. This measures variation in pressure with the tubing and transduces that into an electrical signal. As such, this technology is simply doing what it needs to – evolving with the times.

Borescopes Until recently, borescopes have been considered the height of what’s possible. While inspectors

might previously have been forced to visually check for blemishes by looking down the barrel, they can now dispatch a probe down the tubing to visually detect any defects. Today this comes with the latest digital, HD and wireless technology which enables clearer images, more portable and easy to use devices and greater magnification. This technology, together with air and star gauging is still being used by major companies supplying the US Army with high performance mil-spec M-16 rifles and other advanced machine guns. Air gauges are often used to detect dimensional defects at various stages of the production process, while borescopes enable them to inspect visually the entire interior of the barrel. Data can be then sent wirelessly to a viewer which displays it in an easy to read format.

Lasers and the Future Borescopes and mechanical gauging do indeed have a future in the industry. However, that shouldn’t under-estimate the transformative impact lasers are having. Already they have demonstrated their ability to offer non-contact and non-destructive testing capabilities; to remove operator subjectivity; to provide 100% quantitative results, greater accuracy and improved portability over other technologies. What’s more intriguing is that we appear to have only begun to explore what this technology is truly capable of. Laser technology is already being used in the testing and monitoring process by armies and manufacturers around the world, including in the US, Europe and Asia. However, they are also looking to bring it into the manufacturing process. This is an important capability for any weapons manufacturer, as clients can reject WWW.DEFENCEINDUSTRYREPORTS.COM | 13


Today, laser-based inspection systems are found in many different aspects of the aerospace industry where the accuracy demands continue to grow

an entire job batch over a single defect. As such, the bar is always being set higher and higher in terms of the quality they need to attain. Quality control has an important role to play in this. To do this, lasers need to push forward the level of accuracy they can achieve as surfaces will be newer and, in theory, any problems will be smaller and harder to detect. To achieve this, companies are developing ultra-high resolution lasers which significantly increase the level of accuracy. Yuma Proving Ground, for example, purchased a system from LTC which is capable of achieving an accuracy of +/- 0.001 of an inch. However, they then began investigating ways in which it could push this technology further. The answer was an 155mm ultra high resolution bore mapping solution. Laboratory tests have so far demonstrated that this solution is capable of meeting and exceeding YPG’s goal of accuracy levels exceeding +/-0.0005 inch.

Space, Above and Beyond Nowhere are the requirements for accuracy greater than in the aerospace industry. Here, any defect can lead to a fault which may prove fatal. Back in 2002 LTC began demonstrating to NASA ways in which its laser based measurement


system could work for thrusters powering the space shuttle. Eventually, this led to them being awarded the contract to develop a laser mapping system for the gas generators on board auxiliary power units on both sides of the rocket thrusters. When this was successful, NASA asked for a scanning system to map the interior of the gas generator injection system. As James Doyle, President of LTC recalled, this was a major challenge, saying that the diameter was only 0.095 inch and it was just three inches deep6. Today, laser-based inspection systems are found in many different aspects of the aerospace industry where the accuracy demands continue to grow. A good example can be seen with Hall thruster erosion. Here the problem is high length to diameter equipment which can be extremely difficult for visual inspection. Accuracy can be affected by factors such as lighting, and fatigue of the operative as well as general subjectivity. To work in this space, requires an adapted version of the basic laser technology. While this normally works with a tiny dot being projected onto the surface, it now uses laser diodes and miniature optics that are made small enough to reach inside this extremely confined space. The results have been to create a product which can detect and measure features with a resolution of 0.0002 inch. Research continues into ways in which this technology can be further improved and modified. The different challenges of the various operating conditions mean all measurement and inspection systems will need to be able to adapt to serve a purpose. This is why a high level of consultation and partnership is always required between the provider and end user. While mechanical gauges and borescopes will always have a role to play, it is undoubtedly lasers which hold the key to the future.


References: 1

 Advanced gun barrel technology through plasma:


BEMIS™ Technology:


LTC partners with Chesapeake Testing:


Laser Technology Enhances PCP Manufacturing & Pump Flaw Detection:


Crack detection in Aircraft components:


Laser Mapping for Visual Inspection and Measurement:





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Defence Industry Reports – Next Generation Laser Based Measurement and Inspection Tools  

Defence Industry – Special Report on Next Generation Laser Based Measurement and Inspection Tools – Laser Techniques Company LLC

Defence Industry Reports – Next Generation Laser Based Measurement and Inspection Tools  

Defence Industry – Special Report on Next Generation Laser Based Measurement and Inspection Tools – Laser Techniques Company LLC