ORLANDO, FL, March 21, 2018 — Published through the Laser Institute of America (LIA), renowned author Dr. Kay Ball has revised her book, Lasers – The Perioperative Challenge, to provide updated laser technology information to healthcare professionals. This is the fourth edition; the first was published in 1990, and Dr. Ball notes that much has evolved in the laser world since then.
“Dr. Ball’s book is an excellent read for medical personnel who are new to the use of lasers in medicine and wish to get a comprehensive understanding of lasers used in surgery and other areas outside of the OR. The book is written with the reader in mind and the information is easily understood,” said Gus Anibarro, LIA’s Education Director.
While writing this edition of her book, Dr. Ball focused on evidence from research and published articles on laser procedure applications and outcomes. Since she also travels the world to present laser technology, she included personal clinical experience and addressed common questions she receives from practitioners worldwide.
“Lasers: The Perioperative Challenge takes a complex technology and simplifies it for ready access by nurses, physicians, risk managers, and other healthcare providers. It offers valuable information on how to apply current standards and guidelines for a laser-safe environment,” said Dr. Ball. “I updated the book because there’s such a lack of comprehensive books on the market that address all aspects of laser technology in healthcare.”
The book highlights laser research and applications while incorporating current laser standards and guidelines. Sample laser safety policies provide templates for writing policies and procedures for the clinical environment.
“Everyone needs a really good reference or resource—especially if you’re just beginning your laser services,” said Vangie Dennis, who helped review the book and is the Executive Director of Perioperative Services for WellStar Atlanta Medical Center and Atlanta Medical Center South located in the metropolitan area of Atlanta. “It’s a really great product. It’s the ‘Alexander’ of the operating room—except for lasers.”
Within its 410 pages, the book contains more than 300 illustrations and graphics that are intended to deepen the reader’s understanding of foundational physics, safety, and administrative aspects. There is also an extensive glossary that offers an easy reference for laser terminology.
“As new procedures are introduced and accepted, laser safety is the strong foundation upon which practices are based. When safety is the primary cog in the wheel of laser applications, successful outcomes can be evidenced to validate practice changes. Laser technology continues to advance and mature as safe practices are demonstrated while patients benefit,” said Dr. Ball in the preface of her book.
The 18 chapters are broken up into three sections: “Laser Biophysics, Systems, and Safety,” “Clinical Laser Applications,” and “Administrative Aspects of a Laser Program.”
The cost of the book is $80 for LIA members and $90 for non-members.
“This book is a ‘must’ for all professionals participating in laser surgery and therapy,” said Dr. Ball.
It can be purchased at www.lia.org/store/product/241.
About Laser Institute of America
Laser Institute of America (LIA) is the professional society for laser applications and safety serving the industrial, educational, medical, research and government communities throughout the world since 1968. http://www.lia.org, 13501 Ingenuity Drive, Ste 128, Orlando, FL 32826, +1.407.380.1553.
Design Guidelines for Laser Metal Deposition of Lightweight Structures
By Ake Ewald and Josef Schlattmann
Introduction
Weight critical applications, like parts in the aerospace industry, are driven by lightweight design. Titanium alloys have great potential in lightweight design of structural parts due to their excellent specific mechanical properties. Today, structural parts are manufactured in conventional milling processes. Titanium parts are characterized by poor milling behaviour as well as high material waste rates up to 95 % [1]. The Laser Metal Deposition (LMD) is a layer-wise manufacturing process for the production of three-dimensional complex parts [2].
LMD builds parts based on a nozzle-fed powder, which is solidified by a laser. The process can be used for surface cladding, repair and build-up of parts. For an effective industrial application, it is necessary to identify all advantages and disadvantages. A lowering of the introduction barrier can be achieved by design guidelines helping the engineer early in the product development. With LMD like Selective Laser Melting (SLM), existing manufacturing guidelines cannot be simply adopted. Due to the complex process constraints, a design guideline for LMD has been established.
Complex parts often share simple geometries as a basis. These shapes were identified and used to evaluate the applicability and effectiveness of LMD. Following established lightweight design guidelines, the presented guideline focuses on fine structures. In addition to the manufacturability, the building accuracy and the surface roughness have been investigated, since both have a significant influence on the product quality and the necessity of post processing towards the final shape of a part.
Investigation of process constraints
The investigations are performed with a Trumpf TruDisk 6001 multi-mode continuous wave disk laser with a laser power of 6 kW at a wavelength of 1.03 µm. A three nozzle processing head is used with a rotational table feeder (Fig. 1). The used Ti-6Al-4V powder is spherical and sieved to a fraction less than 80 µm.
Figure 1 Robot cell (TruLaserRobot).
Three different building strategies have been identified in a preliminary design guideline by Möller et al., 2016 [3]. Figure 2 shows the different building strategies. In S1 an inclination is achieved by a stepwise offset (a) between the layers (α = β = 0°). S2 rotates the platform to reach the inclination. The structure is manufactured vertically without an offset between the layers. S3 rotates the machine head to the inclination angle of the structure. The structure can be manufactured without an offset. Besides the three single building strategies, combinations of these are possible, which are not considered at this point. The preliminary guideline published by Möller et al. (2016) showed a high potential in the degree of freedom of building strategy S2 and S3 [3]. For this reason, these strategies were further investigated.
Figure 2 S1: horizontal offset between layer, S2: rotation of platform, S3: rotation of machine head
The mentioned fine structures have been classified as thin walls, curved walls, congregating and aggregating structures. The width of the manufactured structures has been set to a single layer width. The length has been set to 50 mm.
Thin Walls
The build-up of inclined thin walls has been made to investigate
the connection towards the platform,
the influence of the gravitation,
the building accuracy and
the influence on the wall surface.
Both strategies produce a constant and comparable wall thickness under (see Fig.3). It varies due to the surface roughness of about 150 µm. The variation of the measured angle is less than 1°.
Figure 3 Measured wall thickness of the inclined walls manufactured with S2 and S3.
The surface quality of a part has an influence on the appearance, the buy to fly ratio in case of a post processing, and the fatigue strength. The mean values of the surface roughness remain constant with rising inclination angles. The surface roughness of S3 is about 15 µm higher than with S2.
Curved Walls
Curved walls can vary in radius and angle. Curved walls can be divided into curves with their rotational axis parallel, and perpendicular to the building direction (z-axis, Fig. 4). The vertical built up of the curved walls with different radii can be seen in fig. 5.
Figure 4 Sketch of curved elements perpendicular (a) to the building direction and (b) parallel to the building direction.
Figure 5 Set of manufactured parallel curved elements with radius of 0 mm (left) to 30 mm (right).
The radii of the built walls are 0.15 mm to 0.4 mm smaller than expected. An intended vertical edge (radius of 0 mm) produces an outer radius of 3.58 mm. Without post processing, edges should be designed to allow a radius up to the layer width. The radius independent deviation allows the manufacturing in reproducible tolerance fields.
Congregating and Dividing Structures
The separation in congregating and dividing structures is based on the necessity of different manufacturing strategies and constraints in LMD (Fig. 6).
Figure 6 Sketch of the three defined congregating and dividing structures with building direction in z: (a) Y-branch, (b) overhang and (c) reversed Y-branch.
The manufacturing of regular and reversed Y-branches was realised by using S3. To achieve good results, binding on alternating branch sides is recommended (Fig. 7).
Figure 7 Sketch of the Y-branch (above), manufactured Y-branches with the angles β1 = β2 = 30° and β1 = β2 = 45° (below).
Additionally, overhangs were built on the manufactured vertical wall (Fig. 8) to evaluate
the connection between a thin rough wall and a manufactured wall,
the building accuracy, and
the boundary constraints.
The measured angles of the overhangs have an angle deviation of less than 1° up to a manufacturing angle square to the gravity (Tab. 1). This is comparable to the inclined walls. Overhangs show that overhangs with the same or smaller width can be manufactured on thin walls.
Figure 8 Manufactured overhangs with inclination angles from 30° to 90°.
Table 1 Measured inclination angles of the manufactured overhangs. The guidelines derived from the experimental investigation have been collected in a design catalogue according to the VDI 2222 in extracts shown in the figure 9.
Figure 9 Detail from the established design catalogue
Conclusion and Outlook
LMD offers a high degree of freedom in the design of parts. Lightweight parts can benefit from this flexibility. An industrial application can be achieved by design guidelines helping engineers to take the advantages and disadvantages of the LMD process into account during the design process.
The experimental investigation points out that structures based on the basic shapes are producible with constant geometric and surface tolerances, which allows reliable final machining. This is the basis for a successful design process. The building strategy S2 and S3 can be applied. The comparable results of S2 and S3 allow to choose the better fitting strategy for a specific use case.
By focusing on lightweight application, the following aspects have been achieved:
Investigation and manufacturing of basic shapes
Determination of process constraints
Draft of a design guideline.
The developed design catalogue builds a first step towards a comprehensive design guideline for LMD.
M.Sc. Ake Ewald has been a research assistant in the workgroup System Technologies and Engineering Design Methodology at the Hamburg University of Technology since 2013. He works in the methodical product development where he researches the methodical design of hybrid manufactured structural parts using LMD.
Josef Schlattmann is Univ.-Professor at the Hamburg University of Technology. He leads the workgroup System Technologies and Engineering Design Methodology.
References
[1] Allen, J. (2006) An Investigation into the Comparative Costs of Additive Manufacture vs. Machine from Solid for Aero Engine Parts, Rolls-Royce PLC Derby, UK.
[2] Ravi, G.A., Hao, X.J., Wain, N., Wu, X., Attallah, M.M. (2013) Direct laser fabrication of three dimensional components using SC420 stainless steel, Materials & Design, Vol. 47, 731-736.
[3] Möller, M., Baramsky, N., Ewald, A., Emmelmann, C., Schlattmann, J., (2016) Evolutionary-based Design and Control of Geometry Aims for AMD-manufacturing of Ti-6Al-4V Parts, Laser Assisted Net Shape Engineering 9 International Conference on Photonic Technologies Proceedings of the LANE 2016, S. 733–742, DOI: 10.1016/j.phpro.2016.08.075.
One of the biggest challenges for those who maintain a home aquarium is keeping the tank free of pests and contaminants, that pose significant threats to the living creatures inside. While there is no shortage of methods to keep your tank balanced and under control, a recent thread on aquarium enthusiast site Reef2Reef revealed a new defense against unwanted aquarium pests: high-powered lasers.
The thread, focused on “best practices” for laser use in aquariums was started by user CalmSeaQuest, gives ample explanation to how lasers can be used to fight Aiptasia, cyanobacteria, valonia, byprosis, snails, crabs, and beyond.
Using an 1800 mW, 445 nm blue laser, CalmSeaQuest was able to remove all traces of the harmful pests. As a Class IV laser, there are a number of significant risks that come with this laser application. Not only could it cause significant physical harm to the user, the lasers could also cause accidental death or injury to fish and coral in the tank. A laser of this level can additionally cause severe eye damage when viewed without protection.
Because of these risks, it is highly unlikely that pest removal via lasers will ever hit the market. However, for those with proper training and practice, it is an exciting new application of laser technology.
Anxiety disorders affect more than 40 million adults in the United States, alone. Over 6.7 percent of U.S. adults suffer from Major Depressive Disorder. These and other similar disorders are typically treated using a combination of behavioral therapy and pharmaceutical drugs. While generally effective in the realm of treatment, the standard methods do not work for all patients. With that in mind,Francisco Gonzalez-Lima and others at the University of Texas at Austin want to add lasers to the list of potential treatment options.
Using a low powered (less than 60W) infrared laser, that is invisible to the human eye, the alternative treatment for sufferers of these disorders may be on the way sooner, rather than later. The light is placed directly onto the forehead. The laser then energizes the prefrontal cortex: the portion of the brain that controls decision making and higher brain function. By stimulating this part of the brain, patients have seemingly become more receptive to therapy.
A large portion of Cognitive Behavioral Therapy, the therapeutic method preferred by mental health practitioners, relies on the patient’s willingness to unlearn poor habits and thought patterns, and replace them with healthier ones. By stimulating the portion of the brain related to decision making, normally resistant patients may feel a greater drive to open up to new possibilities.
According to Gonzalez-Lima, who has served as a member of the University of Texas’ neuroscience program for over 25 years, the process is safe and has no known adverse side effects.
So how exactly does it work? The study focuses on an enzyme found in all cells called cytochrome oxidase. The enzyme consumes oxygen to generate energy. Essentially, the more oxygen that is converted, the more energy that is generated. Shining the infrared laser on the enzyme increases its activity, converting more energy, thus building up energy reserves for neurons to utilize. Targeting brain cells “charges them up,” leading to greater brain functions. By transforming light into chemical energy, the process is not too different than the brain’s reaction to the prescription treatments. In this instance, however, there are fewer side effects and the cost of long-term treatment could be greatly reduced.
In the study, patients exposed to the infrared laser for just eight minutes showed a greater level of improvement over those who received traditional CBT/pharmaceutical treatments. While the infrared treatments do not cure the ailments overnight, the potential is there for an alternative or simply additional type of treatment for patients who may otherwise be adverse to traditional treatments. When tested on individuals without diagnosed cases of anxiety or depression, there was little change in behavior outside of a small increase in memory retention.
The next step for the study will use the infrared laser with an online therapy program. The program, called Deprexis, uses elements of traditional Cognitive Behavioral Therapy, in a digital setting. Depending on the results of the study, the combined treatment could lead to an alternative to anti-depressants, which often come with a laundry list of side-effects and a hit-or-miss track record of effectiveness from patient to patient.
Light therapy, where patients are exposed to a bright light for a set amount of time, is used to treat seasonal depression. Studies to determine its effectiveness for other types of depression have had mixed results, leading many to question their validity as a viable treatment. Gonzalez-Lima wants to push for greater use of lasers in medical industries, saying that the communities are lagging behind dentists and veterinarians in their embrace of laser technology. Calling this new process “photomedicine,” only time will tell if the treatment proves to be effective in the long term.
Controlling disease-carrying insects is a worldwide issue for agricultural, food, and health industries. Insufficient pest control can ruin an entire season’s crops, or even help spread harmful diseases to consumers. The common method for maintaining control of food resources is through the use of pesticides. While these chemicals are mostly effective in warding off troublesome insects, some species have become resistant to certain compositions, leading to stronger pesticides. While incrementally more effective, the chemicals used to develop the stronger pesticides are not the best substances for safe human consumption.
As researchers have tried to find a new way to control potential infestations or the spread of disease, a Washington-based team may have found a novel solution to growing pest control concerns: lasers.
While the idea of shooting down pesky bugs with a laser beam may seem comical, the concept developed by Intellectual Ventures Laboratory seems like a viable solution to the inevitable question: What happens when pesticides are no longer a sufficient, or health-conscious option?
Enter the Photonic Fence: An electro-optical system that uses lasers, detectors, and data to identify, detect, and shoot down insects before they reach the protected region. While not a particularly new idea, (concepts for a “mosquito fence” have been in the works since the 1980’s) we are closer to a functional prototype than ever before.
The photonic fence determines the size, flight pattern, shape, and frequency of an insect’s wing flap to distinguish species from one another. Based on the data collected, the device is able to determine if the insect is a health threat or not, only firing on those who pose a known danger to the protected region. The photonic fence will also be able to determine if any non-threatening lifeforms are at risk of being caught in the crossfire. This distinction helps to avoid any ecological disruption outside of eliminating the hazardous threat. If the range is obstructed by other insects or lifeforms the device will not fire. The entire process takes nearly a second to occur. While the utilized lasers are low in power, when fired at something as small as a mosquito, the tool is effective in eradicating threats, but causing little to no damage elsewhere.
The goal is to use the photonic fence to protect areas critically affected by disease spreading pests. The fence, once made available, gives a powerful, yet safe alternative to chemical pesticides. Beyond public health applications, the tool could prove to be revolutionary for organic farms and beyond.
If the developing prototypes prove functional and effective, a widespread utilization of the photonic fence will have a huge secondary benefit: data collection. By building an unprecedented database of insect data, the tracking of hazardous pests in crucial areas will be easier than ever before. It goes without saying that the intent is not to eliminate entire species of insects, but rather to curve the devastating impact lost crops and deadly diseases can have on impoverished and threatened communities. To put it simply, this is not your everyday bug swatter.
One of the most significant criticisms of the photonic fence is the lack of reliable energy in Africa, where the photonic fence is needed most. Cost is also a concern of skeptics and critics, who have followed the idea of the “mosquito fence” for decades. To combat this, Intellectual Ventures is working to develop the most affordable, energy efficient way to create and develop the photonic fence to better suit it for where the need and demand exists. The technology is not too different from the standard Blu-Ray player, which does not necessitate a large surge of energy to power up.
Bringing laser technology to the worlds of agriculture and disease prevention is an exciting development for new, exciting laser applications. Using lasers to help provide the world healthier foods, better disease control, and a previously unparalleled understanding of our ecosystems could mean big, positive changes for the world at large. At the very least, with the right operation, the photonic fence could very realistically reveal new information about the world around us, and how we can make it better.
Author’s Note: The original post contained an inaccuracy in regards to the cost of development for the photonic fence. This has since been removed. Apologies for any inconvenience or confusion this may have caused.
