Mark Crawford07.26.10
Prototyping and Production
Changing market conditions make prototyping and production a delicate balancing act.
Mark Crawford
Contributing Writer
Uncertainties about the economy and health care reform continue to impact production schedules for many medical device companies. The capital equipment market remains soft, which is typical of a battered economy. Last year the trend was toward increasing inventory levels for OEMs as the recession took hold, with vendors taking fewer orders and trying to survive. To make matters worse, medical device companies have witnessed a retraction of venture capital-funded start-up activity.
“Large projects have been scaled back and, in some cases, put on hold completely,” said Patrick Pickerell, president of Peridot Corporation, a Pleasanton, Calif.-based contract manufacturer that provides laser processing, EDM, and CNC machining. “The greatest challenge we have faced during the last year has been trying to maintain growth in these uncertain times.”
The U.S. Food and Drug Administration’s (FDA) more cautious approach to granting approvals also is making investors wary, especially venture capital firms. Pickerell said the greater scrutiny in 510(k) submittals definitely has had a negative impact on Peridot’s business. “In some cases customers are experiencing funding issues midway through the development cycle and asking us to carry debt for longer periods of time, while still advancing development,” he noted. “Cash flow and balance sheet metrics are becoming increasingly important.”
Some products that were popular several years ago—such as devices that supported minimally invasive spinal procedures—have become increasingly difficult to fund. Devices for cancer treatment, diabetes care, and cardiovascular procedures are filling the void in 2010.
“Some of the development work from 2009 was pushed into 2010, creating a greater need for quick commercialization as the economy turns around,” said Randall Welch, senior mechanical engineer and industrial designer for Source Scientific LLC in Irvine, Calif., a provider of contract engineering and manufacturing services for medical device firms. “Time-to-market pressures are there for both the prototyping and production sides of the business, especially this year.”
A number of companies, including Potomac Photonics Inc., a laser-based specialty contract manufacturer in Lanham, Md., are experiencing a strong uptick in prototyping orders with a slight increase in production—a possible sign that OEMs are taking advantage of their newfound down time to design new products and have them ready to roll when the economy
finally recovers.
Prototyping Trends
“Many manufacturers in the medical device market seek to engage suppliers capable of providing prototype samples that can be used for both validation and pilot production,” said Steve Bruns, CEO for Pulse Industry LLC, a medical device manufacturer in Hector, Minn. “Typically this occurs in a short-run, low-volume scenario in which the same tool can be employed for the entire product life cycle, yielding a higher return on investment. By connecting prototype tooling with short-run production, device manufacturers not only obtain parts that meet regulatory specs, but generate pilot production runs while waiting for their long-term tools to come online.”
Manufacturers are pushing prototype-parts suppliers to deliver production-quality parts in as little as a month’s time. “Typically, that means a request for more cost-effective aluminum, modular, and hybrid mold fabrications and, in our case, the stents and flexible testing materials we produce,” Bruns continued. “As we manufacture mock arteries and blood vessels using natural latex and FDA-approved clear silicone, we’re able to produce them in a range of configurations, from thin-wall to thick-wall to Y and J hook, and other versions that meet customer requirements. Because these materials are employed in testing or implantation applications, they must be of ‘production quality’ to meet FDA requirements.”
Another trend in prototyping is an ever-increasing selection of materials that better simulate the appearance and function of the final product materials. Prototyping materials include a wide range of resins, both clear and ceramic-reinforced, rapid-manufacturing laser sintering powders, and cast-urethane resins. These provide a much more realistic representation/functionality of the final product, which can speed up FDA approval. “Since materials are improving for rapid prototyping models, the prototypes are more functional and testable,” Welch indicated. “This is important because the FDA requires the product be tested with final materials—in the past, this was mostly done through machining, a more expensive and time-consuming process.”
Time to market can be reduced significantly if the quality and performance of prototype materials mirror production material specifications. Stereolithography (SLA) tends to be the preferred prototyping process when accuracy is the overriding concern. Selective laser sintering (SLS) relies on a laser to sinter powder-based materials together, layer by layer, to form a solid model. This process is the method of choice when durable, functioning parts are required.
About 75 percent of prototyping for medical-device components is done via SLA. “In the past year or so we’ve seen a definite increase in prototyping for larger, more complex pieces of medical equipment, both mobile and fixed,” said Tom Taylor, president of Roush Life Sciences, a product and service provider in Salem, N.H. “Before taking the risk of going into production, OEMs want feedback from end users and focus groups on the design and function of the entire product, not just a component, and technology has improved to allow us to do that. With Roush’s background in automotive manufacturing and design, our 110,000-square-foot facility is equipped with SLA and SLS machines in all sizes, silicone parts, Ren modeling, machining and fabrication, injection and blow molding, thermoforming, carbon fiber, powder coating, as well as a painting booth. Having these capabilities under one roof allows us to rapidly produce larger, more complex parts and equipment, at lower volumes.”
What Customers Want
Some manufacturers are experiencing higher demand for five-axis work from their customers. “We added over $500,000 worth of CNC (computed numerically controlled) equipment in the last year, especially to increase our capacity in CNC turning,” noted Pickerell. “We purchased a Mori Seiki NL2000 multi-axis mill/turn center with bar feed, a Mori Seiki CNC VMC (vertical machining center) with fourth-axis rotary, and also a small Hyundai Kia CNC chucker lathe. All these machines are staying quite busy. We hope to purchase a true five-axis milling machine from Willemin Macodel this year. We are also seeing more demand on the West Coast for excimer laser capability and are currently assessing a purchase in that area.” (Editor’s note: More details on Excimer lasers can be found in a sidebar story on page 105).
To meet customer demand, Pulse Industry offers modular tooling and extrusion solutions that incorporate the use of tooling masters that result in modular mold inserts (speed bases) and master unit dies. The adoption of modular tooling, compared to the conventional approach, gives the company the capability to provide quality parts at a lower cost and with less lead time than previously possible.
“Together with robotic automation, we can run continuous operations in which prototype parts are produced in synch with multiple molding presses and capable of multiple functions,” explained Bruns. “This automation process complements our custom plastic injection molding and enables us to produce high volumes of completed products reliably. However, it’s important to note that in such cases the customer retains ownership of just the cavity and core insert, not the master mold frame. Likewise, sizes are limited to a 3-inch by 10-inch window or smaller.”
The shift to a modular approach means that components of a typical mold base, without the cavity and core elements, results in bases with features that accept part-specific cavity and core inserts. By using standardized modular units, tool-building expenses and lead times are greatly compressed—and that’s a procedure worth noting. “Providing a separate mold for each part that can be adapted to production tooling eliminates the situation in which a single cavity remains dormant for such reasons as changes in tooling specs or maintenance,” added Bruns. “This approach reduces expenses because full production cavities can either be used or replaced if one cavity goes bad or needs modifications.”
Emerging laser technologies are of high interest, including femtosecond, excimer, and disc lasers. While the technologies are proven and are redefining results, they nevertheless have some fairly painful price points, said Pickerell. “Peridot is seeking the right projects to facilitate our expansion into these more exotic laser processes. We currently have eight lasers on the floor, most of which are fairly new,” he noted. “Some of the newest laser technologies may open the door to processing new materials with a smaller heat-affected zone, finer details, and greater throughput.”
One of these new technologies is projector-based rapid prototyping. This method can build functional prototypes using a high-resolution digital light processor projector that images an entire cross section at once, solidifying a liquid photopolymer to create a durable plastic part that’s as good as injection molding for accuracy, material properties, detail, and surface finish. The client can then use the part to verify the design for form, fit, and function prior to full-scale production. This kind of rapid prototyping system creates high-end functional prototypes at twice the speed and at a lower cost than SLA machines. Digital CAD models can be reproduced to within +/- 0.008 inches (+/- 0.2 mm).
Nick Doudoumopoulos, chief technology officer for Potomac Photonics, noted his company is seeing an increasing number of requests for “additive” processes in which material is deposited rather than removed.
“The main focus of these additive processes is manufacturing ultra-high-density interconnect circuitry,” said Doudoumopoulos. “This trend has been under the radar for a while and is still probably several years away from taking off, but designers are beginning to embrace it for new projects. In a nutshell, the benefits are the elimination of photolithography, optical masks, solder, and the environmentally unfriendly printed circuit board manufacturing processes. The approach we have been pushing accomplishes all this and achieves much higher packaging densities than conventional methods. Examples are simplified interposers for flip chip ball grid array (from 2:2:2 to 1:2:1) and a multilayer circuit assembly that includes signal conditioning, signal processing, wireless communication, and a rechargeable power source, all in a cubic-centimeter package that’s compatible with a variety of sensors.”
Controlling Costs
Sometimes capital investment is necessary to control costs. Peridot has invested in the latest multi-axis CNC equipment and has focused on recruiting and retaining top-tier talent to augment existing staff, especially in the area of CNC machining.
“This multi-axis equipment eliminates schedule-killing secondary operations and enables us to hold much tighter tolerances,” said Pickerell. “The Mori Seiki NL2000 mill/turn center we purchased allows for front-end and back-end working with the automatic pick-off spindle. This allows six-sided machining with no second ops. Previously we would turn parts on a lathe and then move them to a CNC vertical milling machine for completion; now it is all done on work center. We are machining a lot more medical-grade plastics in the last year as well.”
Pickerell said constant OEM pressure for compressed development cycles has changed Peridot’s focus on resource maximization. Adding additional shifts has helped address this challenge, as well as implementing lean manufacturing principles to reduce queue times between operations and speed up development times.
“We are reducing queue times by analyzing process flow and reducing waste,” he said. “Our fairly aggressive growth in the last five years resulted in a facility layout that was not optimal—using cell techniques and regrouping work centers has had a positive impact on our organizational efficiencies.”
Peridot currently is implementing its 5S lean initiative (sorting, straightening, systematic cleaning, standardizing, and sustaining). “The amount of reduction in clutter around our facility that resulted in our 5S efforts is amazing,” said Pickerell. “The before and after pictures of some of the revamped areas are truly impressive. The costs involved in such efforts are minimal and the benefits are very tangible.”
Lean is one way to improve quality; another is ISO certification. “At Potomac we have a very strong quality program,” said Doudoumopoulos. “We are both ISO 9001:2008 and ISO 13485:2003 certified. Over the past 12 to 18 months we worked hard to streamline our operations. As a result, our efficiencies are at an all-time high while wasteful spending is down significantly. A whole host of things [occurred], ranging from scrutinizing all expenses and going after the tall poles to making processes more efficient and making better use of the manpower we have available. We would strongly encourage this quality-centric culture in any organization.”
Of course, honest, respectful, and frequent communication is essential for creating positive change. “The slowest step in prototyping/production is usually the communication process,” said Welch. “Clarify the design up front and obtain as much detail from the client as possible. Clients should make sure their documents completely spell out the product specifications for the process specified (machining, rapid prototyping, etc.). Files be in theformat with the proper callouts (texture, finish, color, etc.). This reduces the effort required and speeds up the process.”
Getting customers to explicitly state what they want to do and why they want to do it can be a challenge, noted Bruns. “You’d be surprised to learn how often it takes some customers to define what it is they really want us to accomplish,” he said. “Changing parts and production requirements after we’ve been given a set of tooling specifications can be problematic.”
“In general, the time between first contact by the customer and when we begin making the prototypes can be quite lengthy,” added Doudoumopoulos. “In some instances, a complete manufacturing specification (CAD-ready drawings, dimensional tolerances, finishes etc.) has not yet been fully developed, so time is consumed working out the details. We have found that stronger communication and/or greater disclosure of the end-product functionality helps us better understand the device application and manufacturing price points. Many times we have been able to help customers ‘relieve’ specifications which were arbitrarily constrained, allowing them to realize significant cost benefits.”
The greatest challenge many companies continue to face is the cost associated with prototyping set-up, which includes all the necessary computer-aided design conversions and preparation, fixturing, and laser process development.
“Our business model for prototyping is to break even, as production is our primary focus,” said Doudoumopoulos. “However, once in production, our pricing is extremely competitive. Eventually, prototyping may become so automated in our business that a customer can upload a drawing and then ‘out comes a part.’ Given the nature and uniqueness of laser machining, this evolution will take time. For now, we will continue to focus on streamlining every step of the prototyping process, from specification development to final inspection.”
Excitement Over Excited Dimers
OEMs and contract manufacturers are showing growing interest in excimer laser capability. Excimer lasers generate a light beam by producing excited dimers (two-atom gas molecules such as krypton fluoride, xenon fluoride, argon fluoride, or xenon chloride). Characterized by short wavelengths (193-351 nm), short pulse durations, and high intensities, excimer lasers operate in the ultraviolet part of the spectrum. Optical resolution is less than 1m and high peak power is about 107 watts.
The most notable advantage of excimer lasers over most other lasers is fact that they remove material in a “cold” process where excess heat does not appreciably affect the area around the mark. With most other lasers the area of thermal stress around the mark is nearly as large as the mark itself.
However, the excimer laser is not completely free from thermal effects. Care must be taken not to overlap marks at the same point, or be too close to a fractured or weakened area, because excessive energy can still initiate cracking and lead to material failure. Micromachining advantages include:
• High peak power and small interaction volume, which results in high-energy material ablation with little heat transfer to surrounding material
• Shallow absorption depth, which allows for tighter control of feature depth by controlling the number of pulses to which the material is exposed
• A short optical wavelength, which provides high resolution generation (approximately 1µm features in process materials)
• A large beam size and high peak power, which allow simultaneous large area exposure. —M.C.
Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. His clients range from startups to global manufacturing leaders such as Kohler. He also writes a variety of feature articles for regional and national publications and is the author of five books. Contact him at mark.crawford@charter.net
Changing market conditions make prototyping and production a delicate balancing act.
Mark Crawford
Contributing Writer
Uncertainties about the economy and health care reform continue to impact production schedules for many medical device companies. The capital equipment market remains soft, which is typical of a battered economy. Last year the trend was toward increasing inventory levels for OEMs as the recession took hold, with vendors taking fewer orders and trying to survive. To make matters worse, medical device companies have witnessed a retraction of venture capital-funded start-up activity.
“Large projects have been scaled back and, in some cases, put on hold completely,” said Patrick Pickerell, president of Peridot Corporation, a Pleasanton, Calif.-based contract manufacturer that provides laser processing, EDM, and CNC machining. “The greatest challenge we have faced during the last year has been trying to maintain growth in these uncertain times.”
SLA master pattern used to produce urethan parts. Photo courtesy of Roush. |
Clear part being grown in an SLA machine. Photo courtesy of Roush. |
“Some of the development work from 2009 was pushed into 2010, creating a greater need for quick commercialization as the economy turns around,” said Randall Welch, senior mechanical engineer and industrial designer for Source Scientific LLC in Irvine, Calif., a provider of contract engineering and manufacturing services for medical device firms. “Time-to-market pressures are there for both the prototyping and production sides of the business, especially this year.”
A number of companies, including Potomac Photonics Inc., a laser-based specialty contract manufacturer in Lanham, Md., are experiencing a strong uptick in prototyping orders with a slight increase in production—a possible sign that OEMs are taking advantage of their newfound down time to design new products and have them ready to roll when the economy
finally recovers.
Prototyping Trends
“Many manufacturers in the medical device market seek to engage suppliers capable of providing prototype samples that can be used for both validation and pilot production,” said Steve Bruns, CEO for Pulse Industry LLC, a medical device manufacturer in Hector, Minn. “Typically this occurs in a short-run, low-volume scenario in which the same tool can be employed for the entire product life cycle, yielding a higher return on investment. By connecting prototype tooling with short-run production, device manufacturers not only obtain parts that meet regulatory specs, but generate pilot production runs while waiting for their long-term tools to come online.”
Manufacturers are pushing prototype-parts suppliers to deliver production-quality parts in as little as a month’s time. “Typically, that means a request for more cost-effective aluminum, modular, and hybrid mold fabrications and, in our case, the stents and flexible testing materials we produce,” Bruns continued. “As we manufacture mock arteries and blood vessels using natural latex and FDA-approved clear silicone, we’re able to produce them in a range of configurations, from thin-wall to thick-wall to Y and J hook, and other versions that meet customer requirements. Because these materials are employed in testing or implantation applications, they must be of ‘production quality’ to meet FDA requirements.”
Another trend in prototyping is an ever-increasing selection of materials that better simulate the appearance and function of the final product materials. Prototyping materials include a wide range of resins, both clear and ceramic-reinforced, rapid-manufacturing laser sintering powders, and cast-urethane resins. These provide a much more realistic representation/functionality of the final product, which can speed up FDA approval. “Since materials are improving for rapid prototyping models, the prototypes are more functional and testable,” Welch indicated. “This is important because the FDA requires the product be tested with final materials—in the past, this was mostly done through machining, a more expensive and time-consuming process.”
Time to market can be reduced significantly if the quality and performance of prototype materials mirror production material specifications. Stereolithography (SLA) tends to be the preferred prototyping process when accuracy is the overriding concern. Selective laser sintering (SLS) relies on a laser to sinter powder-based materials together, layer by layer, to form a solid model. This process is the method of choice when durable, functioning parts are required.
About 75 percent of prototyping for medical-device components is done via SLA. “In the past year or so we’ve seen a definite increase in prototyping for larger, more complex pieces of medical equipment, both mobile and fixed,” said Tom Taylor, president of Roush Life Sciences, a product and service provider in Salem, N.H. “Before taking the risk of going into production, OEMs want feedback from end users and focus groups on the design and function of the entire product, not just a component, and technology has improved to allow us to do that. With Roush’s background in automotive manufacturing and design, our 110,000-square-foot facility is equipped with SLA and SLS machines in all sizes, silicone parts, Ren modeling, machining and fabrication, injection and blow molding, thermoforming, carbon fiber, powder coating, as well as a painting booth. Having these capabilities under one roof allows us to rapidly produce larger, more complex parts and equipment, at lower volumes.”
What Customers Want
Some manufacturers are experiencing higher demand for five-axis work from their customers. “We added over $500,000 worth of CNC (computed numerically controlled) equipment in the last year, especially to increase our capacity in CNC turning,” noted Pickerell. “We purchased a Mori Seiki NL2000 multi-axis mill/turn center with bar feed, a Mori Seiki CNC VMC (vertical machining center) with fourth-axis rotary, and also a small Hyundai Kia CNC chucker lathe. All these machines are staying quite busy. We hope to purchase a true five-axis milling machine from Willemin Macodel this year. We are also seeing more demand on the West Coast for excimer laser capability and are currently assessing a purchase in that area.” (Editor’s note: More details on Excimer lasers can be found in a sidebar story on page 105).
To meet customer demand, Pulse Industry offers modular tooling and extrusion solutions that incorporate the use of tooling masters that result in modular mold inserts (speed bases) and master unit dies. The adoption of modular tooling, compared to the conventional approach, gives the company the capability to provide quality parts at a lower cost and with less lead time than previously possible.
“Together with robotic automation, we can run continuous operations in which prototype parts are produced in synch with multiple molding presses and capable of multiple functions,” explained Bruns. “This automation process complements our custom plastic injection molding and enables us to produce high volumes of completed products reliably. However, it’s important to note that in such cases the customer retains ownership of just the cavity and core insert, not the master mold frame. Likewise, sizes are limited to a 3-inch by 10-inch window or smaller.”
The shift to a modular approach means that components of a typical mold base, without the cavity and core elements, results in bases with features that accept part-specific cavity and core inserts. By using standardized modular units, tool-building expenses and lead times are greatly compressed—and that’s a procedure worth noting. “Providing a separate mold for each part that can be adapted to production tooling eliminates the situation in which a single cavity remains dormant for such reasons as changes in tooling specs or maintenance,” added Bruns. “This approach reduces expenses because full production cavities can either be used or replaced if one cavity goes bad or needs modifications.”
Emerging laser technologies are of high interest, including femtosecond, excimer, and disc lasers. While the technologies are proven and are redefining results, they nevertheless have some fairly painful price points, said Pickerell. “Peridot is seeking the right projects to facilitate our expansion into these more exotic laser processes. We currently have eight lasers on the floor, most of which are fairly new,” he noted. “Some of the newest laser technologies may open the door to processing new materials with a smaller heat-affected zone, finer details, and greater throughput.”
One of these new technologies is projector-based rapid prototyping. This method can build functional prototypes using a high-resolution digital light processor projector that images an entire cross section at once, solidifying a liquid photopolymer to create a durable plastic part that’s as good as injection molding for accuracy, material properties, detail, and surface finish. The client can then use the part to verify the design for form, fit, and function prior to full-scale production. This kind of rapid prototyping system creates high-end functional prototypes at twice the speed and at a lower cost than SLA machines. Digital CAD models can be reproduced to within +/- 0.008 inches (+/- 0.2 mm).
Nick Doudoumopoulos, chief technology officer for Potomac Photonics, noted his company is seeing an increasing number of requests for “additive” processes in which material is deposited rather than removed.
“The main focus of these additive processes is manufacturing ultra-high-density interconnect circuitry,” said Doudoumopoulos. “This trend has been under the radar for a while and is still probably several years away from taking off, but designers are beginning to embrace it for new projects. In a nutshell, the benefits are the elimination of photolithography, optical masks, solder, and the environmentally unfriendly printed circuit board manufacturing processes. The approach we have been pushing accomplishes all this and achieves much higher packaging densities than conventional methods. Examples are simplified interposers for flip chip ball grid array (from 2:2:2 to 1:2:1) and a multilayer circuit assembly that includes signal conditioning, signal processing, wireless communication, and a rechargeable power source, all in a cubic-centimeter package that’s compatible with a variety of sensors.”
Controlling Costs
Sometimes capital investment is necessary to control costs. Peridot has invested in the latest multi-axis CNC equipment and has focused on recruiting and retaining top-tier talent to augment existing staff, especially in the area of CNC machining.
“This multi-axis equipment eliminates schedule-killing secondary operations and enables us to hold much tighter tolerances,” said Pickerell. “The Mori Seiki NL2000 mill/turn center we purchased allows for front-end and back-end working with the automatic pick-off spindle. This allows six-sided machining with no second ops. Previously we would turn parts on a lathe and then move them to a CNC vertical milling machine for completion; now it is all done on work center. We are machining a lot more medical-grade plastics in the last year as well.”
Pickerell said constant OEM pressure for compressed development cycles has changed Peridot’s focus on resource maximization. Adding additional shifts has helped address this challenge, as well as implementing lean manufacturing principles to reduce queue times between operations and speed up development times.
“We are reducing queue times by analyzing process flow and reducing waste,” he said. “Our fairly aggressive growth in the last five years resulted in a facility layout that was not optimal—using cell techniques and regrouping work centers has had a positive impact on our organizational efficiencies.”
Peridot currently is implementing its 5S lean initiative (sorting, straightening, systematic cleaning, standardizing, and sustaining). “The amount of reduction in clutter around our facility that resulted in our 5S efforts is amazing,” said Pickerell. “The before and after pictures of some of the revamped areas are truly impressive. The costs involved in such efforts are minimal and the benefits are very tangible.”
Lean is one way to improve quality; another is ISO certification. “At Potomac we have a very strong quality program,” said Doudoumopoulos. “We are both ISO 9001:2008 and ISO 13485:2003 certified. Over the past 12 to 18 months we worked hard to streamline our operations. As a result, our efficiencies are at an all-time high while wasteful spending is down significantly. A whole host of things [occurred], ranging from scrutinizing all expenses and going after the tall poles to making processes more efficient and making better use of the manpower we have available. We would strongly encourage this quality-centric culture in any organization.”
Of course, honest, respectful, and frequent communication is essential for creating positive change. “The slowest step in prototyping/production is usually the communication process,” said Welch. “Clarify the design up front and obtain as much detail from the client as possible. Clients should make sure their documents completely spell out the product specifications for the process specified (machining, rapid prototyping, etc.). Files be in theformat with the proper callouts (texture, finish, color, etc.). This reduces the effort required and speeds up the process.”
Getting customers to explicitly state what they want to do and why they want to do it can be a challenge, noted Bruns. “You’d be surprised to learn how often it takes some customers to define what it is they really want us to accomplish,” he said. “Changing parts and production requirements after we’ve been given a set of tooling specifications can be problematic.”
“In general, the time between first contact by the customer and when we begin making the prototypes can be quite lengthy,” added Doudoumopoulos. “In some instances, a complete manufacturing specification (CAD-ready drawings, dimensional tolerances, finishes etc.) has not yet been fully developed, so time is consumed working out the details. We have found that stronger communication and/or greater disclosure of the end-product functionality helps us better understand the device application and manufacturing price points. Many times we have been able to help customers ‘relieve’ specifications which were arbitrarily constrained, allowing them to realize significant cost benefits.”
The greatest challenge many companies continue to face is the cost associated with prototyping set-up, which includes all the necessary computer-aided design conversions and preparation, fixturing, and laser process development.
“Our business model for prototyping is to break even, as production is our primary focus,” said Doudoumopoulos. “However, once in production, our pricing is extremely competitive. Eventually, prototyping may become so automated in our business that a customer can upload a drawing and then ‘out comes a part.’ Given the nature and uniqueness of laser machining, this evolution will take time. For now, we will continue to focus on streamlining every step of the prototyping process, from specification development to final inspection.”
Excitement Over Excited Dimers
OEMs and contract manufacturers are showing growing interest in excimer laser capability. Excimer lasers generate a light beam by producing excited dimers (two-atom gas molecules such as krypton fluoride, xenon fluoride, argon fluoride, or xenon chloride). Characterized by short wavelengths (193-351 nm), short pulse durations, and high intensities, excimer lasers operate in the ultraviolet part of the spectrum. Optical resolution is less than 1m and high peak power is about 107 watts.
The most notable advantage of excimer lasers over most other lasers is fact that they remove material in a “cold” process where excess heat does not appreciably affect the area around the mark. With most other lasers the area of thermal stress around the mark is nearly as large as the mark itself.
However, the excimer laser is not completely free from thermal effects. Care must be taken not to overlap marks at the same point, or be too close to a fractured or weakened area, because excessive energy can still initiate cracking and lead to material failure. Micromachining advantages include:
• High peak power and small interaction volume, which results in high-energy material ablation with little heat transfer to surrounding material
• Shallow absorption depth, which allows for tighter control of feature depth by controlling the number of pulses to which the material is exposed
• A short optical wavelength, which provides high resolution generation (approximately 1µm features in process materials)
• A large beam size and high peak power, which allow simultaneous large area exposure. —M.C.
Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. His clients range from startups to global manufacturing leaders such as Kohler. He also writes a variety of feature articles for regional and national publications and is the author of five books. Contact him at mark.crawford@charter.net