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BLS Newsletter 2020 – Laser Safety for the Layman

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A Guide for New Laser Safety Officers

By, Christopher Mordica, CLSO

 

Becoming an LSO

Being chosen to become a new LSO for your organization can be an exciting time, as it indicates a level confidence held by your employer that you are capable of taking on this new responsibility that grants you the authority and final say on all things related to laser safety, which let’s not forget brings greater earning potential in terms of raises/promotions and also opens up new career paths where the only limit to your potential is set by how far you wish to take it. But as the old saying goes “with great power comes great responsibility” which is why it cannot be stressed enough that each LSO has both the duty and responsibility to ensure the safety of all personnel that work on or around high-powered lasers. And one of the most effective but challenging ways of doing this is creating and maintaining your own Laser Safety Program.

Within this article I aim at providing some of the very methods taken to establishing the program that I have today, and while not a complete list of everything that encompasses a laser safety program, having these basics will allow you to build a foundation to which the rest can be developed.

 

Developing an Inventory (Lasers Information)

Creating a simple yet robust inventory system will provide any new LSO with a proper foundation upon which their laser safety program can be built on. Based upon my own personal experience as a laser technician over the past decade I understood the importance of why an inventory was not only critical, but in my opinion serves as the very foundation of which any program should be developed based upon one simple rule “How can any LSO ensure the safety of their campus, if they do not understand the hazards present with each laser and where to find them”

The Table below shows only a small portion of what would later make up my site’s laser inventory template. Understanding your lasers capabilities is incredibly important as it allows you the LSO to determine what hazards may be present at based upon things such as Wavelength, Class, Power etc.

 

Performing Audits both Internal and External

Performing Audits for each laser system at your site whether Internal or External can help establish if there are any findings that violate ANSI Z136.1 Standards or OSHA safety regulations. And while understanding all standards and regulations can be a difficult task at times, it ultimately should be looked at as an opportunity to develop your own ability in spotting compliance issues. Such as warn out or incorrect labels and most importantly safety violations that present a direct risk of allowing both exposure and access to the hazard in question. As I stated before having a full understanding of all ANSI and OSHA regulations can take decades of training and practice to correctly implement, which is exactly why I personally reached out to Thomas Lieb, President and Founder of L*A*I – International, an independent company offering both engineering and consulting services to companies dealing with laser technology. After performing your audit if any findings come forth such as compliance or safety hazards it will be important to follow up with your site EH&S and create a risk assessment of which findings to tackle first, with safety of coarse taking priority above all else.

Example of an OSHA Violation found during an audit

• OSHA Violation
–          While taking a closer look at the station it was found that there was a safety issue present that was previously unknown, the station has a very large opening along the direct beam path in which the beam can escape. The wavelength used by this laser is one that can be transmitted directly to the retina causing permeant blindness. It was later reviled that a cover for this section of the station did exist at one point but was scrapped due to an increased need to perform maintenance in a timely manner to get production running again.

NOTE: The final point to make for this section of why performing audits are critical, is because they can also uncover the history of the machine in question. As such can be seen with the example provided, where due to lack of knowledge and respect for laser safety resulted in the removal of physically guarding that was designed and intended to protect against both exposure and access of the known hazard present.

 

Affected vs. Authorized and knowing the difference

The last topic I will touch on is one related to training your Affected  vs. Authorized users and ultimately knowing the difference between the two. (Note: The definitions provided are unique to the authors site and are not defined in ANSI Z136.1)

Affected

Laser associates whom are trained on how to operate and run production in a Class 1 environment but who are NOT trained in performing maintenance on the system and Shall never operate the laser with guards or interlocks bypassed. *No PPE required*
Authorized

Laser associates whom are trained to perform routine preventive maintenance and or troubleshooting that may result in taking the laser from a class 1 environment to a class 3B or higher. Authorized associates Shall be trained in proper PPE use/handling prior to any work performed on said system. *PPE REQUIRED*

CONCLUSION

The industry of laser technology will continue to grow exponentially for years to come and will require more individuals that understand and can apply the standards correctly. And if my own journey of becoming an LSO/CLSO has taught me anything it would be that 1. Misinterpretation of standards is more common than not, and 2. That associate compliance to any program developed depends solely on the culture that is established by your organization through leading by example.

And finally, I will leave you with a quote that has always stuck with me through the years and at its core represents the very essence of why we all have become LSOs.

“an ounce of prevention is worth a pound of cure”

 

About the Author

Christopher Mordica was born and raised in Columbia MO and he started studying Photonics at the age of 16 in high school. He enrolled at Indian Hills Community College and achieved a diploma in Electronics/Computer Occupations, followed by an A.A.S Degree in Laser Electro Optics technology. He has been working in the medical manufacturing field for the last decade holding titles of Manufacturing Laser Technician I / II, Sr. Laser Manufacturing Support Technician / ILSO/ CLSO and is currently the Equipment Maintenance Supervisor / CLSO for Integer in Chaska MN, overseeing all 5 buildings on their campus. Recently Christopher has also joined both the ANSI Z136.9 and TSC-7 Subcommittees. He continually looks to improve the laser safety program at his site in the hopes that it can be used as an example for all other sites within the corporation. His goal now is to develop a training program for his alumni so that the future generation of techs can have a better understanding of what is expected and needed out in the field.

 

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Source: https://issuu.com/marketlia/docs/lia_today_marapr_2020/19?fr=sNGQzYjEzMTY5ODA

BLS Newsletter 2020 – Reducing Facility Risk of Disposables and Accessories Entering the OR

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By, Casey Branham, MBA/CMLSO

 

There is a wide range of practices in how hospitals receive healthcare laser system (HCLS) disposables and accessories at their facility. As someone who works for a third-party provider that does this over 90,000 times a year, I’ve seen them all.

In some hospitals, the surgeon may ask for the instructions for use (IFU), or biomed may ask for the UL mark. In others, supply chain may just ask about the cost. There are very few exchanges where we see a Medical Laser Safety Officer (LSO) or Surgical Director present to review HCLS accessories and disposables – which is now a requirement under the latest Z136 guidelines.

 

Updated American National Standards Tackle Third-Party Provider Risk

ANSI Z136.3 (Sections 1.3.2.8 & 4.3.2) requires that a Medical Laser Safety Officer approve each HCLS and equipment prior to use. This includes any disposables and accessories for use in laser cases. This is necessary to ensure the correct combinations of items are used for each case.

For example, there is difference between an FDA approved item and an FDA approved system. The difference is that a disposable and an accessory can each be FDA approved, yet that specific combination may not be FDA approved based on the OEM and the IFUs for each.

When a facility owns its lasers and purchases fibers directly from the OEM, there isn’t much risk of running into that issue. However, most hospitals do not have a process – or the appropriately certified laser safety professionals – in place to ensure items brought in by third-party providers are also approved (1.4.2).

The result? Hospital staff may be unknowingly introducing risk into their OR that could impact patient outcomes.

The LSO community has an opportunity to educate healthcare professionals on a thorough intake procedure needed to control what enters the OR and what combination of HCLS accessories and disposables can be used without limiting the surgeon’s access to cutting edge technology.

 

A Good Place to Start: OEM vs. Non-OEM Fibers

My co-worker Richard Gama, CMLSO, presented a dynamic risk assessment tool at the International Laser Safety Conference last year to help LSOs take a closer look at the risk around non-OEM disposables used on different OEM devices. The concept is that risk is not binary or static – it is dynamic. Adding items to a procedure or using different non-OEM combinations may increase the risk that an unsafe event occurs in a laser case.

For example, the risk profile is very different between flexible fiber CO2 versus Holmium laser disposables. In the case of Holmium laser disposables, the fiber optic transmits laser energy. In the case of flexible fiber CO2, the CO2 fibers are made of different materials entirely (Silica hollow core or OmniGuide Polymer). The differences in materials create more aspects that require risk evaluation.

Holmium lasers emit 2100 nm wavelength energy, and the Holmium fibers transmit this energy. This relationship limits risk to the integrity of the fiber and the dexterity of the cladding. The IFUs for the Holmium fibers are validated for use on many different manufacturers’ Holmium lasers. However, the LSO should review and approve and the laser settings prior to use.

There are several well-established third-party Holmium fiber manufacturers that exist today with proven track records. The established track record combined with the simple make up of Holmium fibers makes a good argument for this being a low risk pairing.

The CO2 flexible fiber is a comparatively recent invention. OmniGuide claims to have produced the first hollow core polymer CO2 laser fiber in 1998. The OmniGuide fiber (known as a flexible instrument) carries 10,600 nm laser energy as well as helium gas at a predefined PSI based on the inner lumen of the flexible instrument.

The addition of this pressurized gas dramatically changes the risk profile. Due to this, the challenges around third-party silica fibers on OmniGuide equipment are many. The challenges for CO2 flexible fiber systems manufactured for use with silica fibers are not as dynamic because the material of the fiber is the same as the one intended for use on the HCLS.

Approving silica fibers for use on the OmniGuide laser creates several potential issues. The correct PSI setting for the pressurized gas is first and foremost, as no one wants to see an unanticipated tissue interaction or an airway fire. Once that risk is properly evaluated, the next risk is the durability of the silica fiber.

The OmniGuide polymer fiber is ideal for CO2 energy for a few reasons. The OmniGuide selling point is that it fails safely. Compared to a hollow core silica fiber, this is true. OmniGuide claims 23,000 surgeries without a single instance of a fiber breaking. The Maude database shows that a few hollow core silica-based CO2 fibers have broken inside patients or on the surgical field. CO2 laser energy does not diffuse at the same rate as Holmium energy; therefore, the risk of burns is high if the silica fiber breaks. In 2019, OmniGuide posted a product safety alert around the use of third-party silica fibers on their HCLS.

Approving silica CO2 laser fibers for use with systems designed to transmit CO2 energy through a silica fiber are much simpler to evaluate. The major issue there is identifying whether the IFU has a conversion chart for the PSI setting based on the CO2 silica laser fiber inner lumen diameter. The type of gas recommended for use with the HCLS OEM fibers and the one on the IFU for the non-OEM fiber also needs evaluation.

Imagining a Better Process to Reduce Risk

In order to mitigate the risk described above, hospitals should implement a defined process that involves LSO review of the IFU for HCLS, accessories and disposables. There should also be a follow-up evaluation to determine whether the combined products suggested for use fits that of the IFU for the laser, accessory and the disposable.

After the LSO approves each item use and their combined use, the process moves to the value analysis committee in the same way a facility evaluates a new purchase. Facilities that follow the value analysis process may slow down how quickly an item is available for use, but they ensure the item has been properly reviewed. I often see this process used for new HCLS entering facilities, but I rarely see it when disposables or accessories are involved.

In summary, any process that allows a laser disposable into the facility OR without review from the LSO and a subsequent trip to value analysis increases facility risk. Third-party providers should be required to add any disposable to their contract, and any item should go through the value analysis committee prior to the disposable being placed on contract or entering the OR.

This reduces the risk that disposables enter a facility without proper review of the related IFUs. If your facility has not followed this process in the past, requesting all related IFUs for all contracted items from your third-party partner is a quick way to evaluate the risk you have today. Adopting a more rigorous disposable entry path policy is a proven way to limit risk in the future.

 

About the Author

Casey Branham is the Operations Director at Agiliti where he works with OEMs to select new technology offerings and partners with large Health Systems around their laser program needs, including the service and delivery of over 330 surgical cases per day. Casey has over 7 years of experience as a certified laser operator and has over 6 years of experience managing multiple ambulatory surgery centers across the Eastern United States that provided laser treatments. He has also been a Board-certified medical laser safety officer for over 2 years

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Source: https://issuu.com/marketlia/docs/lia_today_janfeb?fr=sMDNkODkwMDg4OA

Goodbye Adhesives, Hello Thermal Direct Joining

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Laser Pre-Treatment and the Future of Hybrid Materials

Interview by Liliana Caldero

Originally in LIA TODAY July/August 2019.

Throughout the world, scientists are rising to the challenge of developing new techniques to improve the eco-friendliness of products and production lines. Germany has been among the strongest supporters of the movement to be more environmentally responsible. Innovations resulting from this momentum may lead to more efficient manufacturing, which could ultimately cut costs without compromising quality. Hybrid materials are growing in importance in the search for strong, lightweight materials that produce fewer CO2 emissions. Dominic Woitun of the German-based Bosch is among the researchers investigating techniques for effective thermal direct joining of hybrid materials. Joining dissimilar materials such as metals and plastics can pose a challenge; this challenge is often solved with the use of adhesives or screws with sealants. Adhesives may work, but according to Woitun, they leave a larger carbon footprint. This is where thermal direct joining comes in. The process that Woitun is researching involves using laser ablation to shape macroscopic structures into a metal surface; the structures  are then penetrated  with a  molten polymer which enables mechanical fastening, for instance. After solidification, a strong joint is obtained, which replaces the need for an adhesive. The shapes, or geometries, created by the laser play an important role in the strength and reliability of the joint, so better understanding the relationship between these geometries and the resulting joint will help make this a viable alternative to adhesives. Woitun shared with LIA TODAY why he started researching the impact of laser geometries on thermal direct joining of hybrid materials, and why companies could consider this an answer to adhesives.

LIA: For some in our community, the term ‘thermal joining’ brings to mind laser welding of metals; for those who are new to the concept of thermal direct joining of hybrid materials, could you describe what this process can look like, step-by-step?

DW: Thermal direct joining is a joining technique for metals and polymers. The adhesive forces of a thermoplastic melt to metals is used to join both partners. No additional adhesive is needed. However, to achieve strong joints, some form of surface pretreatment is needed. Laser structuring is a promising approach.

The process steps to a finished part could look like this:

  1. Preparation: prior surface treatment (e.g. by laser ablation)
  2. Joining: Many different techniques are possible! The only premise is a somehow molten polymer in the joining interface that can penetrate the structure. This can be achieved, for example, by heating the metal part with some kind of heat source and then pressing it onto the plastic part. Or, in my case, by using injection molding and overflowing the metal part with molten polymer in the molding tool.
  3. Finishing: the molten polymer solidifies instantly and directly after joining the joint has almost its final strength

LIA: Tell us about what drove you to research thermal direct joining?

DW: In order to meet today’s requirements for weight reduction and thus emission reduction, hybrid components are becoming increasingly important. Especially in the context of electrification. One main challenge for the production readiness of hybrid composites is the joining technology. Currently, hybrid parts are often joined by adhesives or screws in combination with sealants. Therefore, the interfaces need to be handled with special care and must be cleaned before joining. After joining, the parts need a certain curing time before they can be further processed. When it comes to recycling, there is almost no way to separate the often used and recyclable thermoplastic material from the duroplastic adhesives. This makes the current solutions time-consuming and costly.

LIA: What are you researching right now and how does it help to solve these challenges?

DW: Direct joining of metals and polymers based on a laser-pretreatment bypasses these problems and produces strong and media tight joints directly after the joining process. However, the enormous variety of laser sources, in combination with their adjustable parameters, open up endless possibilities for structures on the metal surface. This often ends in time-consuming empirical studies to find the best settings for one specific use case. That’s why I’m investigating the influence of largely separated surface characteristics on the joint properties by generating well-defined structures on the metal surface by laser ablation. My aim is to find the best weighting and composition of surface characteristics to define the optimal structure for an application.

LIA: What benefits could companies gain from utilizing direct joining?

DW: If direct joining would replace adhesives, it would mean re-planning our production lines. Manufacturing chains could be shortened and combined because the components can be manufactured, joined and further processed in-line.

LIA: What further research is needed in this area?

DW: Fully describing the interdependencies in the boundary layer of the metal-polymer joint exclusively with experimental research will be difficult. For this reason, we are currently working on a multiscale simulation approach to gain better understanding of the interdependencies. One main challenge is to transfer the effects of different surface characteristics (microscale) to strength predictions at component level (macroscale).

LIA: What could this research mean for the future?

DW: Direct joining in general allows redesigning joints in comparison to adhesive bonds. If, in addition, the capability of the joint can be predicted, manufacturing processes can be optimized and the confidence in those joints will be increased.

Photo of Dominic Woitun, Bosch

See Dominic present, “Precise Laser Structures as a Tool to Understand Metal-Polymer Joints“  (Authors: Dominic Woitun, Michael Roderus, Thilo Bein, Elmar Kroner) at the Laser Macroprocessing Conference Track on October 8, 2019. Register for ICALEO here: www.lia.org/conferences/icaleo

SOURCE: https://issuu.com/marketlia/docs/lia_today_augsept-2019/18?fr=sOTg0ZjIzMzQwOA

Surface Functionalization with LIPSS Continues to Expand into New Industries

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Interview by Liliana Caldero
As featured in LIA TODAY July/August 2019.

 

Laser researchers from Bundesanstalt für Materialforschung und -prüfung (BAM) have teamed up with medical researchers from Johannes Kepler Universität Linz (JKU) and Kepler Universitätsklinikum Linz (KUK) in a European research project to show the potential of laser materials processing for suppressing the adhesion of human cells to titanium alloy implants such as miniature pacemakers. This is only one of many research projects investigating the potential uses of surface functionalization. With the use of lasers, technical surfaces can be structured at nano- and micro-scales to mimic textures found in nature, copying the unique characteristics that make them hydrophobic, anti-bacterial, or anti-reflective; this is known as surface functionalization. In most cases, this type of processing reduces or even removes the need for certain chemical coatings.

The field of laser-based surface functionalization is expanding rapidly and new potential applications abound; this technology offers innovative solutions for biotechnology, automotive manufacturing, and machine building. As with most new solutions, the big question is how to make it fast and scalable to promote industry-wide adoption

According to Camilo Florian-Baron of BAM, the trick is using linearly polarized high-intensity ultrashort laser pulses to create laser-induced periodic surface structures, or LIPSS, which can produce these desirable biomimetic properties. With advancements in fast laser scanning heads and recent high-repetition rate ultra-short pulsed femtosecond lasers, surface functionalization with LIPSS is becoming more available for R&D and manufacturing. Florian-Baron and his research team are investigating the future of LIPSS applications. With more than 50 publications on LIPSS coming from BAM in the past decade, the group is among the leading institutions progressing the understanding of the interaction between ultrashort laser pulses and matter for micro- and nano-fabrication of materials[1]. Florian-Baron will be presenting at ICALEO 2019 on the latest applications of surface functionalization through LIPSS. He shared with LIA about some of the unexplored potential of this emerging field and some of the interesting projects his team has been honored to work on.

CFB: Usually, materials processing at industrial scales with lasers requires the scanning of the sample of interest with tightly focused laser beams or sweeping the beam on a static sample surface. It means that the micro- and nanofabrication over large areas could take a long time due to the need of irradiating line-by-line or spot-by-spot until the desired machining process is completed. In contrast, laser-induced periodic surface structures (LIPSS) can be fabricated on virtually any material when irradiated with linearly polarized high-intensity ultrashort laser pulses, typically under loosely focusing conditions (large beam spots). The morphology of LIPSS corresponds to parallel arranged period lines featuring periods that can be controlled between only ~100 nm and a few micrometers. Their orientation is strongly influenced by the laser beam polarization used. It means that it is possible, for example, to produce nanometric spaced lines all perpendicular to the laser polarization with a laser beam size at the irradiated surface that is 1000 times bigger than their periodicity covering a larger area with nanostructures faster than conventional laser-direct writing. In an additive approach, these surface nanostructures can be easily superimposed to other surface microstructures, resulting in hybrid surface structures with multiscale surface roughnesses. Through all these surface topographies, along with accompanying laser-induced chemical alterations at the surface, different surface functionalizations can be realized, ranging from structural colorization or antireflective properties (as on certain butterflies), over a control of surface hydrophilicity/-phobicity (as on lotus leaves), and toward unidirectional liquid transport (as realized by moisture-harvesting lizards or bark bugs).

Techniques based on lasers could be defined as contactless digital manufacturing techniques, currently constituting a real industrial- revolution that is transforming the production processes from the early stages of research and development to mass production and marketing [2]. The biggest difference in comparison with other fabrication methods is the possibility to perform design changes using only mouse clicks instead of modifying an already fabricated prototype, resulting in a faster, cheaper and more efficient way of materials processing. Besides that, the current advancements in fast laser scanning heads, combined with high-repetition rate femtosecond lasers allow producing LIPSS at industrially relevant scales and processing speeds, which in the end will be translated into cheaper fabrication costs at higher production rates. Importantly, the whole fabrication process is compatible and reproducible at room temperature and air atmosphere, which is very attractive to most industries that work under similar conditions.

LIA: Your research team has been investigating the mechanisms responsible for the formation of LIPSS to better understand how and when those structures can be formed; what are some of the exciting applications you are researching?

CFB: Our research group is specialized in developing strategies based on lasers to understand the mechanisms of interaction between ultrashort laser pulses and matter, to micro- and nanofabricate materials for specific applications.

Last year, we successfully finished a 3-year international research project funded by the European Commission called LiNaBioFluid [3] where one of the goals was to produce LIPSS on industrially relevant materials and scales to decrease the friction coefficient in tribological applications, as well as developing strategies based on LIPSS for passive fluid transport applications, including commercial lubricants, all based in biomimicking structures found in nature.

As a continuation of this project, currently we are working in another European project called CellFreeImplant [4] (see the link below) that uses LIPSS to avoid unwanted cell growth on medical devices, such as smart medical implants. The promising results are at present in the hands of our medical project partners with close collaborations with a large pacemaker manufacturer to potentially take this laser-based approach for so-called ‘leadless’ pacemakers to real patients in the future.

One of the most exciting feelings when researching LIPSS is that the variety of the current applications are spread over different technological areas. On one hand, this allows us to learn more

Image: Steel sample processed by a femtosecond laser. The colour effects of the four fields result from the diffraction of the ambient light by the laser-induced periodic nanostructures on the surface. Source: BAM, Division Nanomaterial Technologies

about the real producer and manufacturer problems, while at the same time solving them in an efficient way. On the other hand, and personally, with the research that we are currently doing at

BAM, I feel that I am not only achieving milestones in a research project to fulfill it, I think that one day the research, time and resources we are investing could be applied in this particular case to real medical devices that any person can benefit from. In the end, the feeling is that with our tiny steps, we are making the world a better place.

 

LIA: With all that is being done already, what additional research would you like to see happen in this field?

CFB: Currently, the understanding of the formation dynamics achieved by the growing community of scientists researching LIPSS have allowed the development of different applications in different and diverse fields. However, due to the many different and specific conditions needed to fabricate them, a general model that includes all the possible experimental outcomes in the different materials is not available yet. More efforts should be focused on developing more complete models that will provide a deeper understanding of the formation mechanisms and

laser-matter interaction dynamics that give rise to LIPSS structures. Consequently, with more understanding of the mechanisms involved, novel and innovative applications could emerge.

There are several areas where LIPSS could be useful but currently are barely explored, such as the case of catalytic and self-cleaning surfaces, antireflective treatments based on nanostructures instead of organic or inorganic coatings and perhaps bacterial or antibacterial surfaces for food manufacturing or applications in medicine [1,4,5].

From a practical point of view, the production speed of LIPSS is currently further boosted up by several research groups in Germany, France and Spain, featuring novel scanner technologies based on polygon scanners, along with high repetition rate ultrashort laser sources reaching MHz to GHz pulse repetition rates.

References

  1. http://doi.org/10.1109/JSTQE.2016.2614183 : Laser-induced Periodic Surface Structures – A Scientific Evergreen (Open access)
  2. https://www.tdx.cat/bitstream/10803/400403/1/CFB_THESIS.pdf
  3. https://www.bam.de/Content/EN/Standard-Articles/Topics/Energy/article-linabiofluid.html
  4. https://www.researchgate.net/project/CellFreeImplant-Cell-free-Ti-based-Medical-Implants-due-to-Laser-induced-Microstructures-H2020-FETOPEN-4-2016-2017-CSA.
  5. https://doi.org/10.1007/s00339-017-1352-0 (Open access)
  6. https://doi.org/10.1016/j.apsusc.2017.02.174

 

Photo of Camilo Florian-Baron, Bundesanstalt für Materialforschung und -prüfung (BAM)

See Camilo present, “Surface Functionalization by Laser-Induced Periodic Surface Structures“  (Authors: Camilo Florian-Baron, Sabrina V. Kirner, örg Krüger, Jörn Bonse) at the Laser Nanomanufacturing Conference Track on October 8, 2019. Register for ICALEO here: www.lia.org/conferences/icaleo

 

SOURCE:  https://issuu.com/marketlia/docs/lia_today_augsept-2019/10?fr=sZjFhZTIzMzQwNg

Laser Additive Manufacturing’s Journey to Commercialization

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By Andrew Albritton

As seen in LIA TODAY

LASER ADDITIVE MANUFACTURING CHALLENGES

Laser Additive Manufacturing (LAM), as it pertains to powder based manufacturing, is a technique that utilizes the interaction of lasers and base materials to construct a product, rather than removing material from a pre-constructed block of material. LAM is quickly approaching the critical point of being more than a method to produce prototypes and small runs of one-off parts – it is poised to turn everything we know about mass production on its head. Professor Dr. Minlin Zhong, President-Elect of LIA and Director of the Laser Materials Processing Research Center at Tsinghua University, believes it surpasses all available alternative methods.  Prof. Dr. Zhong  says “LAM shows obvious advantages on freeform manufacturing, including free geometry, free structures, free strengthening mechanism, free microstructures, free performance and even free scale (from macro, to meso, to micro, to nano),”. Manufacturers who use LAM are able to reduce the waste of materials commonly associated with traditional subtractive manufacturing methods; decrease the weight of parts by cutting out filler materials; and have more control over material properties resulting in stronger, more complex, lighter, and more efficient parts. With such exceptional technology currently at our disposal, why hasn’t LAM been more widely adopted?

IT’S EXPENSIVE

One of the most commonly cited reasons is that the costs to produce parts through LAM are prohibitive. The key driver of these high costs is that the supply chain for metal powders is not yet optimized for LAM technology. Materials are expensive, custom made, or not readily available. The Metal Powder Industries Federation (MPIF) states in its 2017 PM Industry Roadmap that, “A better understanding of the precursor materials impact on the metal AM process is required. Traditionally, precursor materials have been existing thermal spray powders that have not been refined/tuned to the AM process limiting optimization.” LAM parts producers are often using metal powders that have not been designed for use in LAM processes, which frequently results in suboptimal products.

According to MPIF, as of 2017, there are approximately 12 suppliers of metals for Additive Manufacturing (AM) for the international market, most produce stainless steel, cobalt-chrome, and titanium, with a few supplying aluminum alloys, copper, super alloys, platinum, Inconel, tungsten, molybdenum, and tool steels. With so few suppliers and a sparse number of common material types, there is a bottleneck for providing quality affordable metal powders to the LAM industry. With companies expanding the selection of materials that can be laser processed, it is vital that the problem of material availability be resolved. For example, Nuburu has produced a “blue” laser which operates at the 450 nm wavelength, and is capable of processing gold, aluminum, brass, and copper.

SUPPLY AND DEMAND

What can be done to improve the supply chain and reduce the cost of LAM part production? The metal powder industry does not supply enough quality powder to support widespread adoption of LAM, while early adopters of LAM applications do not create enough demand to drive competition into the metal powder market to reduce prices. A first step to get these industries operating in unison will be the creation and mass adoption of standards, specifications, and best practices in regards to metal powders. By standardizing metal powder properties for best final product properties, metal powder suppliers would be able to build up an inventory without relying on custom special orders. Specifications on how surplus powder from a project can be reused could also help introduce addition cost savings to manufacturers.

STANDARDS FOR QUALITY CONTROL

Another hurdle for LAM is microstructural quality, uniformity, and repeatability. To become a replacement for more legacy manufacturing methods, LAM needs to produce parts consistently and continuously that are to specifications. With traditional subtractive manufacturing methods, there are several quality control points where product is inspected and defects are addressed prior to the next step, resulting in no wasted effort past the point of failure. With LAM, the part in question is created from the ground up; this determines the final product’s quality, microstructure, and mechanical properties simultaneously. The process is completed with either a perfect or defective final product. Paul Denney, Director of Advanced Process Development with IPG Photonics, states, “Unlike machining where you start with a “block” of material with known quality and properties, additive production of parts requires a combination of motion with the prediction of the microstructures, mechanical properties, and stresses. Because the properties are closely connected to how the material is deposited, this greatly complicates the development of processing procedures and parameters.”

What methods can be implemented into a given LAM process to help ensure quality of the final product? The first quality control concerns are addressed long before the process begins. Starting materials must be certified as appropriate for the application, the order of operations of the production device should be scrutinized to ensure that the final product will be to spec with minimal waste, and the machine itself must be operating at peak parameters. As the production of a LAM product can take an extended amount of time, any loss of power to the point of interaction can have detrimental effects to the end product and even the products in queue. Loss of power can be caused by an actual power failure, a dirty or damaged optic, or other origins. With the structural integrity of a LAM part resting critically on the success of every step of the process, it is imperative that the process is stringently optimized and the machine is operating at peak performance. Here is what Paul Denney has to say about the subject:

“Because of the additive manufacturing approach in bed based systems, even if defects can be detected and possibly ‘corrected’, any changes may not be possible. An example of this may be what is done if a ‘defect’ is flagged in a single part in a batch of parts being produced. One approach would be to stop the processing and ‘correct’ the defect. However, if this is done then the thermal history for all of the parts may be altered and all parts may now be out of the desired properties. Another approach would be to stop processing on the part with the defect, but this again would alter the heat load on the complete batch or the time between other parts being produced which may again alter the properties. So any monitoring system will need to detect changes prior to the formation of any defects while at the same time any corrections must be made within the acceptable parameter range.”

There is a thin line between success and failure: one small interruption can ruin an entire batch of product. What can be done to prevent this?

As Paul explained, this is not a single issue, LAM processes need both a method to detect defects and the ability to immediately respond to them. A starting point is to ensure that redundancies are incorporated into the build process so that if a common defect occurs at a certain stage, there are defined responses the system can take automatically to correct them. In the case of a laser lens issue, it may be beneficial to incorporate additional laser delivery systems to the process as a redundancy to pick up where a suboptimal device has failed in real time.

EVALUATING THE FINAL PRODUCT

In addition to inline defect detection, the industry as a whole will require a standardized best practice for evaluating finalized parts. For traditional manufacturing methods, a sample of the produced part pool is selected for evaluation via destructive and non-destructive tests to certify whether a set of parts are built to specifications. As many LAM-produced parts are complex and costly to produce, it seems wasteful to destroy a set of them to certify them. In the paper “Evaluation of 3d-Printed Parts by Means of High-Performance Computer Tomography” presented at ICALEO 2017, authors Lopez, Felgueiras, Grunert, Brückner, Riede, Seidel, Marquardt, Leyens, and Beyer reviewed the viability of X-ray Computer Tomography (CT) and 3d scanning as methods to detect inferior AM parts. The paper concludes that the CT method best fits the needs of the AM industry. According to Lopez et. al, “Computer tomography can quantify all complex structures in scope of the proposed demonstrator and delivered deviation values of the measured structure, providing a good base for comparison across demonstrators made by different methods, materials and dimensions. Porosity or defects down to 3 µm can be determined by the used CT system.” Currently, CT scanning a LAM part is a time consuming process, but with additional focus on improvement it could become an essential quality non-destructive control method for finalized parts to evaluate complex internal structures.

TOO MANY ALTERNATIVES

A third barrier to the spread of LAM is the multitude of alternative methods in the industry. As stated by Prof. Dr. Zhong, “Some conventional metal deposition technologies such as arc building-up welding, plasma building-up welding and electronic building-up welding can also fabricate metallic components in near shape. Their deposition rate and productivity may be high and the costs may be lower, but normally they are limited in fabricating complex geometry and accuracy.” Freeform manufacturing is where LAM excels, but despite its many advantages over alternative methods, it has an Achilles heel.

One advantage of alternative manufacturing methods is the speed at which a product can be produced. However, according to Paul Denney, this speed gap is closing faster every day.

“While higher laser powers allow for higher deposition rates but at the expense of lower resolution, some researchers are looking to maintain the resolution by combining multiple lasers into an additive deposition system. Research groups and equipment builders are investigating how best to handle multiple lasers in the same processing area. There are other areas that may be investigated including power distribution to improve the interaction between the power and laser beam to improve efficiency of the process and to minimize defects. This could improve the deposition rates while at the same time maintaining quality.”

Prof. Dr. Zhong hopes that soon LAM researchers will, “improve the materials diversity, increase the dimension (to square meters), increase the deposition rate and decrease costs. A hybrid approach to combine LAM with the conventional additive manufacturing methods may be a solution to achieve the above targets.” The concept of a hybrid production system that can combine multiple lasers with fast alternative methods where complexity is not a requirement could lend itself to faster build times.

THE LATE ADOPTERS

Earlier in the article, we touched on the final barrier to the wide spread success of LAM: industry standards. Current standard offerings from ASTM and ISO cover Design, Materials and Processes, Terminology, and Test Methods. Additionally, new processes are created frequently and new standards are being developed every year in an attempt to keep up. It is unclear how much of the industry has adopted these existing specifications. Until the entire market accepts a set of standards for all steps of the Additive Manufacturing process and supply chain, the evaluation of AM parts will remain a costly endeavor that will limit AM’s potential. MPIF expresses a bleak outlook on metal AM in its State of the PM Industry in North America – 2017 document: “Despite all the fanfare, true commercial long-run production still revolves around only three product classes: titanium medical implants, cobalt-chrome dental copings, and cobalt-chrome aircraft nozzles.” The truth of the matter remains that without a set of clearly defined standards, the LAM industry will continue to remain confined to early adopters like the Aerospace and Medical fields. With the benefits in intricacy and weight saving advantages LAM should have obvious opportunities in the automotive and electronics industries.

Markets are watching LAM for innovative uses before taking the plunge and embracing the technology. Currently, LAM may appear to have a bad Return on Investment (ROI) if producers only hope to replicate their existing products through LAM rather than innovating their parts to capitalize on its strengths. In the words of Paul Denney, “If AM is supposed to make big impact, companies are going to have to rethink their parts; determine how AM allows for changes in the design and possibly improve the performance. The benefits can come in many forms which could be a weight savings, a production savings, and/or a performance savings.” The industry needs to challenge its way of thinking about production to allow the benefits inherent to LAM to propel their production and parts to new levels of performance. Paul Denney provided the following illustration: “With the formation of properties ‘locally’ instead of in ‘bulk,’ it is possible to produce ‘gradient’ materials. The ‘gradient’ can come by changes to the properties of a given chemistry of material or by using materials with different chemistries. As an example: a bracket could be produced for a jet engine that has high temperature properties near the engine but as the bracket extends to an attachment point, the properties/chemistry can be altered to improve the fatigue properties.”

LAM has a bright future and many engineers and scientists are working to unlock its full potential. Once the barriers of the supply chain, dynamic quality control, speed of production, and process standardization have been resolved, it is highly likely the LAM will be a manufacturing method of choice.

 

ACKNOWLEDGEMENTS

Paul Denney, Director of Advanced Process Development with IPG Photonics and LIA’s Past President

Prof. Dr. Minlin Zhong, Director of Laser Materials Processing Research Center at Tsinghua University

and LIA’s President-Elect

 

References:

Lopez, E., Felgueiras, T., Grunert, C., Brückner, F., Riede, M., Seidel, A., Marquardt, A., Leyens, C., Beyer, E. (2018). Evaluation of 3D-printed parts by means of high-performance computer tomography. Journal of Laser Applications 30, 032307; https://doi.org/10.2351/1.5040644