Mark Crawford, Contributing Writer09.10.21
Computerized numerical control (CNC) machining is an essential process in the manufacture of medical devices. This specialized equipment removes material with incredible precision through various cutting methods, including drilling, turning, and grinding. Enabled by increasingly advanced (and more user-friendly) software, “CNC machine tools can be programmed to navigate to different positions at different rates of speed, along specific paths and patterns,” stated Bruce Dworak, president of Hobson & Motzer, a Durham, Conn.-based manufacturer of precision metal components and assemblies for the medical device market and other industries. “CNC machinery can be configured to accommodate a specific product or can be used for a wide variety of applications.”1
As medical devices continue to get smaller and more complex, with added functionality and tighter tolerances, CNC equipment manufacturers are intent on improving their machines to meet these ever-increasing design and production challenges, which often push the limits of CNC machining technology. Automation and robotic-assisted CNC machines are key technologies that improve efficiency, quality, and tolerance control. The efficiencies of automation help CNC machines stay competitive with additive manufacturing (AM), especially for the manufacture of complex shapes with extremely tight tolerances. CNC machines can produce machine parts as small as 0.01 inches in diameter, with tolerances as tight as 0.0002 inches.
CNC machines in the medical device industry are constantly advancing to the point where machinists also need to be increasingly adept at programming because everything is controlled with computers. “This has completely changed the necessary skill sets of the manufacturing workforce,” said Sean Mikus, general manager for the Costa Rica operations for Tegra Medical, a Franklin, Mass.-based full-service contract manufacturer for the medical device industry.
The equipment companies that support medical device manufacturing are also challenged by these workforce restraints, as well as demands for quicker turnarounds and smaller lot sizes.
“Modern CNC machines are designed to meet these challenges by performing more efficiently than ever before,” said Dan Walker, director of business development for Tsugami/Rem Sales, a Windsor, Conn.-based exclusive importer of Precision Tsugami CNC machine tools, including lathes and milling machines. “The utilization of tooling technologies, which adapt to changing manufacturing requirements, increases productivity and operational flexibility. Quick-change tooling, oscillation cutting, lights-out machining, and more powerful CNC controls generate more up-time with less human intervention.”
Latest Trends
Equipment manufacturers continue to improve their milling and Swiss-turning machines, especially regarding control advances and off-the-shelf automation integration. CNC shops are also investing in automation systems and other technologies to enhance integration and keep the quality and productivity at the highest level.
Parts are becoming increasingly complex, which is changing what the machine manufacturers are offering in their product lines. “To maintain accuracy, you do not want to have multiple operations,” said Joe Haupers, director of sales for Swiss Precision Machining, a Wheeling, Ill.-based contract manufacturer of complex, high-precision, multi-faceted machined components for several industries, including medical devices. “The machine manufacturers have recognized this and are offering very complex multi-axis machines that are well-suited for small complex parts.”
For example, Tsugami/Rem Sales adopts technologies that can merge multiple operations and reduce takt time—for example, integrating laser cutting with a CNC Swiss lathe. This type of “hybrid” equipment can also make small, high-precision cuts that cannot be achieved with conventional machining. “Our LaserSwiss technology combines multiple separate operations into one, which provides cost savings to the end user while significantly reducing takt time and scrap and improving process capability, while delivering quick ROI,” said Walker.
Lasers are still one of hottest market segments in CNC machining—laser cutting, laser welding, laser texturing, and laser knurling. Combining laser processing with machining in hybrid equipment eliminates steps and saves time. For example, by combining laser cutting and welding with traditional Swiss turning, laser-Swiss machines can perform multiple processes in a single set-up, which shortens lead times and also streamlines the validation process.
“Hybrid equipment is very exciting,” said Stephen Pfeifer, senior engineering manager for Jabil Healthcare, a division of Jabil Inc. Jabil, a manufacturing solutions provider, has over 260,000 employees across 100 locations in 30 countries. “Today’s technologies are advancing rapidly and we have add-ons to CNC machines that were not possible 10 years ago. For example, integrated part marking, specialized tool holders to provide an indexed axis on a Swiss turn, and inspection technologies are much easier to integrate than ever before.”
Jabil Healthcare recently developed a hybrid machining solution for a client that integrated CNC machining, part marking, and part verification into a single operation. Using off-the-shelf components, including cameras, a robot, and laser-etch machines, Jabil condensed multiple operations into a single machining step. “This allows one operator to effectively move from raw material to machined, marked, and verified product immediately and virtually eliminates the potential for mix-ups and human error,” said Pfeifer. “With vision systems and part-marking integrated into our Swiss lathes, we have been able to achieve a process where raw material comes in on a barfeeder and fully machined, marked product comes out. This is a gigantic advancement when it comes to part traceability in the manufacturing process.”
Time can also be saved through continued advancements in flexible work holding. Fixtures that are easy to change over and reduce wasted motion help optimize tool life, reduce downtime between set-ups, and make machining more efficient and cost-effective. This can also be aided by automation. “One of the exciting new features of robots is their ability to actually be the fixture—holding the part being machined and moving it as needed,” said Mikus. “This is a paradigm shift.”
Robots are also becoming more user friendly, making it easier to automate processes. As these and other Industry 4.0 technologies take hold, fewer workers have both the technology and computer skills needed to run these programs. This makes automation and robotics even more important for counteracting the shortage of skilled workers. Machinists who increase their skill sets to include managing robots and cobots will be able to manage even more machines. “Automation will work in conjunction with other developments such as artificial intelligence [AI] and software optimizers,” added Mikus. “A worker can load the machine with standard programs and 3D drawings from the CAD/CAM software and let the robots do the work.”
What OEMs Want
The biggest challenge in using CNC machining in the medical device industry is the cost of the equipment. In an industry like automotive, for example, where a company is making millions of engines, the up-front investment is easily recovered quickly through the high volume of sales. In contrast, medical device manufacturing is mostly a low-volume and high-mix business, which makes it harder to justify high up-front costs.
Even so, the state of machining is fairly advanced in the medical industry, due to a willingness to embrace process improvement in all areas and push the current manufacturing systems to get the quickest and most cost-effective process possible.
Medical device manufacturers (MDMs) continue to be cost-sensitive, so machine shops and other CMs are constantly looking for ways to balance cost and performance, whether it is a refinement in existing equipment, a workflow adjustment, or investing in a new technology that will have a high ROI.
“It is not always the cheapest product that brings the highest advantage for the customer,” said Florian Dierigl, business development manager for the medical industry for TYROLIT, an Austrian-based manufacturer of bonded grinding, cut-off, sawing, drilling, and dressing tools. “Engineers should be involved more in the decisions to find a balance for price/performance.”
MDMs are designing smaller parts with numerous intricate and high-precision features, especially for minimally invasive procedures. Even though these components are smaller and harder to make, with tolerances in the 25-40 micron range (roughly half the width of a human hair), MDMs want them made faster and at low cost. To meet these expectations, machine manufacturers focus on generating greater up-time, quicker changeover, and better predictability and reliability—which often can only be achieved with the help of automation. “The skills gap in precision manufacturing is creating an environment where all types of automation are required to stay competitive and keep the work in the U.S,” said Walker. “OEMs are looking for a supply chain that embraces advanced technologies that improve quality while also reducing costs.”
In addition, MDMs are beginning to focus more on the environmental impacts of manufacturing their devices. There is growing interest in minimizing the negative environmental impacts of making these devices across their entire lifecycle, from raw materials through end of life. As a result, MDMs are expecting more detailed information on manufacturing practices, materials, and the CO2 impact of each part from their machining partners. Since CNC machining has a huge role in that lifecycle, CNC practices will have a significant role in determining environmental impacts.
“This is already happening in other industries, such as automotive,” noted Mikus. “In fact, even getting a request for proposal in some other industries is dependent upon a CM’s existing sustainability activities and even the software platforms it uses. While it is not yet a factor in medical device manufacturing, this is likely on the horizon, so we can learn a lot from how other industries that use CNC machining are already handling these requests.”
New Technology Advances
In orthopedics, especially grinding femur parts for artificial knee implants, the trend is toward using state-of-the-art super-abrasive grinding wheels rather than the conventional aluminum oxide grinding wheels, which were used in the past. “This makes it possible to decrease grinding cycle times and increase output per wheel,” said Dierigl. “As a result, less frequent tool changing and therefore reduced tool changing time is achieved because of longer lifetime of the grinding tool. As an example, for artificial hip cup grinding, customers have experienced a cycle time reduction for the roughing process from 10 minutes down to one minute—a 90 percent increase in productivity.”
Major advancements in the area of carbide tooling have made it possible to machine exotic materials much more effectively than in the past—even hardened materials. In many cases, OEMs may think grinding is absolutely necessary to cut a particular material or to achieve a certain tolerance—but this is not always the case anymore. “We have been very successful in eliminating grinding operations and using lower-cost CNC milling operations to achieve the same result,” said Pfeifer.
Numerous advancements in CNC machining have improved efficiency and accuracy in recent years. The broad spectrum of equipment that is now available makes machine choices much easier when it comes to specific parts or products. “What you find today is that engineers are designing parts to be made on specific equipment,” said Haupers. “This has not happened in the past. They are collaborating with the manufacturer more than ever when it comes to design for manufacturing. Machine manufacturers realize this and have made great strides and improvements in the technology behind their machines.”
For example, orthopedic bone screws are a high-volume, common yet complex component in the medical manufacturing space. While many CNC Swiss machine lathe companies provide the necessary tooling to produce these products, very few can meet the exacting specifications and speed required to be competitive and meet demand. For many CMs, the solution has been to purchase more machines to add capacity.
Tsugami/Rem Sales, however, has designed a system that reduces bone screw cycle times up to three times. The Tsugami S206-II can be mounted with dual thread whirling units, which are the heaviest and most robust in the 20-mm class of machines. “The Tsugami S206-II is also heavier than other machines in this class,” said Walker. “More weight translates to more mass, which can allow for faster, high-precision metal removal. One-piece base casting supports the entire machine tool, assuring maximum rigidity.”
Over the past decade, numerous machine platforms have increased their accuracy and output, including CNC vertical mills, horizontal mills, Swiss-style multi-axis turning centers, multi-spindle and Swiss-style multi-spindle (both designed for high-volume machining), precision multi-process machining centers for extremely complex parts, and CNC molding equipment capable of molding very complex geometries.
“We are seeing great benefits from using various off-the-shelf building blocks ranging from non-contact sensors to cameras combined with our Swiss machines and mills to create expanded capabilities,” said Pfeifer.
“There is huge value in being able to trigger an event from the machine as it is running to ensure that safety features are in place or to verify product is being produced to specification.”
Oscillation cutting (also called low-frequency vibration) is a technological breakthrough that oscillates a servo axis to help break chips in tough-to-cut materials, such as stainless steel. This action reduces heat in the cut, but does not diminish tool life or surface finish. “By oscillating the specified axis, cutting is performed by synchronizing the oscillation of the specified axis with the rotation of the main spindle,” said Walker.
“Interruption in the cut by oscillation breaks material into small chips, rather than long stringy ones. Productivity is increased by significantly reducing operator intervention to remove hanging or ‘bird-nesting’ chips.”
It is not just the hardware of CNC machines that is advancing; it is also the software. The control system/software is the brain of a CNC machine and continues to get “smarter.” In addition to being used for programming the machine, the control system can also be used to train operators. The most up-to-date information and set-up procedures can be downloaded to the machine so operators never need to go hunting for documentation, saving time and boosting efficiency.
As the Internet of Things (IoT) connects more equipment, statistical process control [SPC] data can be viewed live, allowing supply chain partners and customers to see data in real time. Machine vendors that are also part of this ecosystem can be notified immediately of any issues that arise with the function of their machines.
“The evolution of the CNC control software makes it easier to implement SPC capabilities, which is very convenient as more customers are asking for certificates of compliance and/or performance,” said Mikus. “They really want the statistical analysis. When it’s baked right into the manufacturing process it is a lot easier to supply.”
It is hard to overemphasize the growing importance of collecting, managing, sharing, and analyzing all kinds of data in the manufacturing process. CNC machines are already an important data source on process performance. This data extends beyond the shop floor and into all areas of a company, where it helps inform business decisions. “As an example, digitally collected measurement data can be analyzed and on-the-fly machine offset adjustments can be made to ensure a process is continually centered in the tolerance window,” said Mikus. “Real-time machine utilization becomes a live data point that can be tracked to aid the capital investment decision-making process.”
Overall, additive manufacturing cannot compete with the speed and accuracy of CNC machining for most parts. However, the capabilities of AM continue to advance rapidly, with some medical device engineers designing components that can only be made with AM and not CNC equipment. Currently, AM is most useful for prototyping and making manufacturing jigs, fixtures, and tooling in the shop for use on the line to fix minor placement and tracking problems, or simply to make the line run more smoothly. In most cases, CNC is still the preferred process for medical device components, especially for high volumes. When AM is used for production, it is typically for low-volume runs. Although AM requires less labor, it can have higher material and capital expense costs and also does not achieve quite the same quality of surface finishes or tolerances that CNC machining can.
However, CNC machining can still be a great complement to additive manufacturing and vice versa. “I see great potential for the utilization of additive machining combined with traditional milling,” said Pfeifer. “As the cost to make additive parts decreases, it will allow for small runs of near net shape parts that can be finished to the precise tolerances needed by the OEM. I believe additive manufacturing will continue to advance, but it is difficult to say if it will ever be able to achieve the surface finishes required.”
Moving Forward
Many engineers, even those with a deep understanding of CNC machining, are often incorrect in knowing what certain machines can and cannot do, or the kind of complex parts that can be machined. Sometimes an MDM’s design shows a feature on a part that the CM knows will be inefficient and expensive to manufacture. This is where the CM uses design for manufacturing (DFM) to determine the most efficient way to use CNC machining—or a combination of technologies—to make the part and hold the tight tolerances required. Surface finish is becoming increasingly important for reducing friction between parts in assemblies and is often evaluated in DFM.
CNC machines will continue to advance in the coming years and use improved processing controls, more axes, lasers, IoT sensor technologies, wireless transmission, user interfaces, and software and cloud influences.
With all these available tools and technologies, the trick is integrating them seamlessly with CNC equipment to make them as efficient and productive as possible, especially for specific types of products. CNC integrators help CMs maximize the productivity and value of their CNC machines, particularly with non-traditional technologies like laser processing.
“For example, you can purchase a CNC machine from one vendor, and then work with the integrator to modify, augment, and customize the machine, as well as provide the software to tie it all together,” said Mikus. “Integration is the process that makes it all work well together and optimizes the CNC experience.”
Reference
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. He also writes a variety of feature articles for regional and national publications and is the author of five books.
As medical devices continue to get smaller and more complex, with added functionality and tighter tolerances, CNC equipment manufacturers are intent on improving their machines to meet these ever-increasing design and production challenges, which often push the limits of CNC machining technology. Automation and robotic-assisted CNC machines are key technologies that improve efficiency, quality, and tolerance control. The efficiencies of automation help CNC machines stay competitive with additive manufacturing (AM), especially for the manufacture of complex shapes with extremely tight tolerances. CNC machines can produce machine parts as small as 0.01 inches in diameter, with tolerances as tight as 0.0002 inches.
CNC machines in the medical device industry are constantly advancing to the point where machinists also need to be increasingly adept at programming because everything is controlled with computers. “This has completely changed the necessary skill sets of the manufacturing workforce,” said Sean Mikus, general manager for the Costa Rica operations for Tegra Medical, a Franklin, Mass.-based full-service contract manufacturer for the medical device industry.
The equipment companies that support medical device manufacturing are also challenged by these workforce restraints, as well as demands for quicker turnarounds and smaller lot sizes.
“Modern CNC machines are designed to meet these challenges by performing more efficiently than ever before,” said Dan Walker, director of business development for Tsugami/Rem Sales, a Windsor, Conn.-based exclusive importer of Precision Tsugami CNC machine tools, including lathes and milling machines. “The utilization of tooling technologies, which adapt to changing manufacturing requirements, increases productivity and operational flexibility. Quick-change tooling, oscillation cutting, lights-out machining, and more powerful CNC controls generate more up-time with less human intervention.”
Latest Trends
Equipment manufacturers continue to improve their milling and Swiss-turning machines, especially regarding control advances and off-the-shelf automation integration. CNC shops are also investing in automation systems and other technologies to enhance integration and keep the quality and productivity at the highest level.
Parts are becoming increasingly complex, which is changing what the machine manufacturers are offering in their product lines. “To maintain accuracy, you do not want to have multiple operations,” said Joe Haupers, director of sales for Swiss Precision Machining, a Wheeling, Ill.-based contract manufacturer of complex, high-precision, multi-faceted machined components for several industries, including medical devices. “The machine manufacturers have recognized this and are offering very complex multi-axis machines that are well-suited for small complex parts.”
For example, Tsugami/Rem Sales adopts technologies that can merge multiple operations and reduce takt time—for example, integrating laser cutting with a CNC Swiss lathe. This type of “hybrid” equipment can also make small, high-precision cuts that cannot be achieved with conventional machining. “Our LaserSwiss technology combines multiple separate operations into one, which provides cost savings to the end user while significantly reducing takt time and scrap and improving process capability, while delivering quick ROI,” said Walker.
Lasers are still one of hottest market segments in CNC machining—laser cutting, laser welding, laser texturing, and laser knurling. Combining laser processing with machining in hybrid equipment eliminates steps and saves time. For example, by combining laser cutting and welding with traditional Swiss turning, laser-Swiss machines can perform multiple processes in a single set-up, which shortens lead times and also streamlines the validation process.
“Hybrid equipment is very exciting,” said Stephen Pfeifer, senior engineering manager for Jabil Healthcare, a division of Jabil Inc. Jabil, a manufacturing solutions provider, has over 260,000 employees across 100 locations in 30 countries. “Today’s technologies are advancing rapidly and we have add-ons to CNC machines that were not possible 10 years ago. For example, integrated part marking, specialized tool holders to provide an indexed axis on a Swiss turn, and inspection technologies are much easier to integrate than ever before.”
Jabil Healthcare recently developed a hybrid machining solution for a client that integrated CNC machining, part marking, and part verification into a single operation. Using off-the-shelf components, including cameras, a robot, and laser-etch machines, Jabil condensed multiple operations into a single machining step. “This allows one operator to effectively move from raw material to machined, marked, and verified product immediately and virtually eliminates the potential for mix-ups and human error,” said Pfeifer. “With vision systems and part-marking integrated into our Swiss lathes, we have been able to achieve a process where raw material comes in on a barfeeder and fully machined, marked product comes out. This is a gigantic advancement when it comes to part traceability in the manufacturing process.”
Time can also be saved through continued advancements in flexible work holding. Fixtures that are easy to change over and reduce wasted motion help optimize tool life, reduce downtime between set-ups, and make machining more efficient and cost-effective. This can also be aided by automation. “One of the exciting new features of robots is their ability to actually be the fixture—holding the part being machined and moving it as needed,” said Mikus. “This is a paradigm shift.”
Robots are also becoming more user friendly, making it easier to automate processes. As these and other Industry 4.0 technologies take hold, fewer workers have both the technology and computer skills needed to run these programs. This makes automation and robotics even more important for counteracting the shortage of skilled workers. Machinists who increase their skill sets to include managing robots and cobots will be able to manage even more machines. “Automation will work in conjunction with other developments such as artificial intelligence [AI] and software optimizers,” added Mikus. “A worker can load the machine with standard programs and 3D drawings from the CAD/CAM software and let the robots do the work.”
What OEMs Want
The biggest challenge in using CNC machining in the medical device industry is the cost of the equipment. In an industry like automotive, for example, where a company is making millions of engines, the up-front investment is easily recovered quickly through the high volume of sales. In contrast, medical device manufacturing is mostly a low-volume and high-mix business, which makes it harder to justify high up-front costs.
Even so, the state of machining is fairly advanced in the medical industry, due to a willingness to embrace process improvement in all areas and push the current manufacturing systems to get the quickest and most cost-effective process possible.
Medical device manufacturers (MDMs) continue to be cost-sensitive, so machine shops and other CMs are constantly looking for ways to balance cost and performance, whether it is a refinement in existing equipment, a workflow adjustment, or investing in a new technology that will have a high ROI.
“It is not always the cheapest product that brings the highest advantage for the customer,” said Florian Dierigl, business development manager for the medical industry for TYROLIT, an Austrian-based manufacturer of bonded grinding, cut-off, sawing, drilling, and dressing tools. “Engineers should be involved more in the decisions to find a balance for price/performance.”
MDMs are designing smaller parts with numerous intricate and high-precision features, especially for minimally invasive procedures. Even though these components are smaller and harder to make, with tolerances in the 25-40 micron range (roughly half the width of a human hair), MDMs want them made faster and at low cost. To meet these expectations, machine manufacturers focus on generating greater up-time, quicker changeover, and better predictability and reliability—which often can only be achieved with the help of automation. “The skills gap in precision manufacturing is creating an environment where all types of automation are required to stay competitive and keep the work in the U.S,” said Walker. “OEMs are looking for a supply chain that embraces advanced technologies that improve quality while also reducing costs.”
In addition, MDMs are beginning to focus more on the environmental impacts of manufacturing their devices. There is growing interest in minimizing the negative environmental impacts of making these devices across their entire lifecycle, from raw materials through end of life. As a result, MDMs are expecting more detailed information on manufacturing practices, materials, and the CO2 impact of each part from their machining partners. Since CNC machining has a huge role in that lifecycle, CNC practices will have a significant role in determining environmental impacts.
“This is already happening in other industries, such as automotive,” noted Mikus. “In fact, even getting a request for proposal in some other industries is dependent upon a CM’s existing sustainability activities and even the software platforms it uses. While it is not yet a factor in medical device manufacturing, this is likely on the horizon, so we can learn a lot from how other industries that use CNC machining are already handling these requests.”
New Technology Advances
In orthopedics, especially grinding femur parts for artificial knee implants, the trend is toward using state-of-the-art super-abrasive grinding wheels rather than the conventional aluminum oxide grinding wheels, which were used in the past. “This makes it possible to decrease grinding cycle times and increase output per wheel,” said Dierigl. “As a result, less frequent tool changing and therefore reduced tool changing time is achieved because of longer lifetime of the grinding tool. As an example, for artificial hip cup grinding, customers have experienced a cycle time reduction for the roughing process from 10 minutes down to one minute—a 90 percent increase in productivity.”
Major advancements in the area of carbide tooling have made it possible to machine exotic materials much more effectively than in the past—even hardened materials. In many cases, OEMs may think grinding is absolutely necessary to cut a particular material or to achieve a certain tolerance—but this is not always the case anymore. “We have been very successful in eliminating grinding operations and using lower-cost CNC milling operations to achieve the same result,” said Pfeifer.
Numerous advancements in CNC machining have improved efficiency and accuracy in recent years. The broad spectrum of equipment that is now available makes machine choices much easier when it comes to specific parts or products. “What you find today is that engineers are designing parts to be made on specific equipment,” said Haupers. “This has not happened in the past. They are collaborating with the manufacturer more than ever when it comes to design for manufacturing. Machine manufacturers realize this and have made great strides and improvements in the technology behind their machines.”
For example, orthopedic bone screws are a high-volume, common yet complex component in the medical manufacturing space. While many CNC Swiss machine lathe companies provide the necessary tooling to produce these products, very few can meet the exacting specifications and speed required to be competitive and meet demand. For many CMs, the solution has been to purchase more machines to add capacity.
Tsugami/Rem Sales, however, has designed a system that reduces bone screw cycle times up to three times. The Tsugami S206-II can be mounted with dual thread whirling units, which are the heaviest and most robust in the 20-mm class of machines. “The Tsugami S206-II is also heavier than other machines in this class,” said Walker. “More weight translates to more mass, which can allow for faster, high-precision metal removal. One-piece base casting supports the entire machine tool, assuring maximum rigidity.”
Over the past decade, numerous machine platforms have increased their accuracy and output, including CNC vertical mills, horizontal mills, Swiss-style multi-axis turning centers, multi-spindle and Swiss-style multi-spindle (both designed for high-volume machining), precision multi-process machining centers for extremely complex parts, and CNC molding equipment capable of molding very complex geometries.
“We are seeing great benefits from using various off-the-shelf building blocks ranging from non-contact sensors to cameras combined with our Swiss machines and mills to create expanded capabilities,” said Pfeifer.
“There is huge value in being able to trigger an event from the machine as it is running to ensure that safety features are in place or to verify product is being produced to specification.”
Oscillation cutting (also called low-frequency vibration) is a technological breakthrough that oscillates a servo axis to help break chips in tough-to-cut materials, such as stainless steel. This action reduces heat in the cut, but does not diminish tool life or surface finish. “By oscillating the specified axis, cutting is performed by synchronizing the oscillation of the specified axis with the rotation of the main spindle,” said Walker.
“Interruption in the cut by oscillation breaks material into small chips, rather than long stringy ones. Productivity is increased by significantly reducing operator intervention to remove hanging or ‘bird-nesting’ chips.”
It is not just the hardware of CNC machines that is advancing; it is also the software. The control system/software is the brain of a CNC machine and continues to get “smarter.” In addition to being used for programming the machine, the control system can also be used to train operators. The most up-to-date information and set-up procedures can be downloaded to the machine so operators never need to go hunting for documentation, saving time and boosting efficiency.
As the Internet of Things (IoT) connects more equipment, statistical process control [SPC] data can be viewed live, allowing supply chain partners and customers to see data in real time. Machine vendors that are also part of this ecosystem can be notified immediately of any issues that arise with the function of their machines.
“The evolution of the CNC control software makes it easier to implement SPC capabilities, which is very convenient as more customers are asking for certificates of compliance and/or performance,” said Mikus. “They really want the statistical analysis. When it’s baked right into the manufacturing process it is a lot easier to supply.”
It is hard to overemphasize the growing importance of collecting, managing, sharing, and analyzing all kinds of data in the manufacturing process. CNC machines are already an important data source on process performance. This data extends beyond the shop floor and into all areas of a company, where it helps inform business decisions. “As an example, digitally collected measurement data can be analyzed and on-the-fly machine offset adjustments can be made to ensure a process is continually centered in the tolerance window,” said Mikus. “Real-time machine utilization becomes a live data point that can be tracked to aid the capital investment decision-making process.”
Overall, additive manufacturing cannot compete with the speed and accuracy of CNC machining for most parts. However, the capabilities of AM continue to advance rapidly, with some medical device engineers designing components that can only be made with AM and not CNC equipment. Currently, AM is most useful for prototyping and making manufacturing jigs, fixtures, and tooling in the shop for use on the line to fix minor placement and tracking problems, or simply to make the line run more smoothly. In most cases, CNC is still the preferred process for medical device components, especially for high volumes. When AM is used for production, it is typically for low-volume runs. Although AM requires less labor, it can have higher material and capital expense costs and also does not achieve quite the same quality of surface finishes or tolerances that CNC machining can.
However, CNC machining can still be a great complement to additive manufacturing and vice versa. “I see great potential for the utilization of additive machining combined with traditional milling,” said Pfeifer. “As the cost to make additive parts decreases, it will allow for small runs of near net shape parts that can be finished to the precise tolerances needed by the OEM. I believe additive manufacturing will continue to advance, but it is difficult to say if it will ever be able to achieve the surface finishes required.”
Moving Forward
Many engineers, even those with a deep understanding of CNC machining, are often incorrect in knowing what certain machines can and cannot do, or the kind of complex parts that can be machined. Sometimes an MDM’s design shows a feature on a part that the CM knows will be inefficient and expensive to manufacture. This is where the CM uses design for manufacturing (DFM) to determine the most efficient way to use CNC machining—or a combination of technologies—to make the part and hold the tight tolerances required. Surface finish is becoming increasingly important for reducing friction between parts in assemblies and is often evaluated in DFM.
CNC machines will continue to advance in the coming years and use improved processing controls, more axes, lasers, IoT sensor technologies, wireless transmission, user interfaces, and software and cloud influences.
With all these available tools and technologies, the trick is integrating them seamlessly with CNC equipment to make them as efficient and productive as possible, especially for specific types of products. CNC integrators help CMs maximize the productivity and value of their CNC machines, particularly with non-traditional technologies like laser processing.
“For example, you can purchase a CNC machine from one vendor, and then work with the integrator to modify, augment, and customize the machine, as well as provide the software to tie it all together,” said Mikus. “Integration is the process that makes it all work well together and optimizes the CNC experience.”
Reference
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. He also writes a variety of feature articles for regional and national publications and is the author of five books.
