Mark Crawford09.16.14
Technology is a double-edged sword. Although it can improve orthopedic product design and production, it’s also hard to keep up with. As OEMs demand dimensional tolerances as tight as +/- .0001 inches, machining and tooling providers must combine the latest science with their innovative know-how and best practices to deliver increasingly challenging products. The trend toward miniaturization continues to impact the medical market, pushing the capabilities of micro-machining. In their efforts to save money wherever they can, OEMs are seeking efficiencies by contracting with “one-stop” companies that also can handle secondary operations such as anodizing and laser engraving. They also want partners who are skilled at machining complex parts or products from more challenging materials such as titanium, cobalt chrome, titanium and polyether ether ketone (PEEK).
Orthopedic OEMs, therefore, are eager to work with creative machine shops that can figure out how to streamline operations, such as using single setups and eliminating secondary operations. Quick changeovers and fewer machining/tooling steps are essential for optimizing throughput and time to market. Advanced five- and seven-axis milling machines have the capability to complete complex orthopedic designs in a single operation, including parts or products with complex geometry. For example, multiple functions such as milling, gun drilling and thread whirling can be completed at different stations on multi-axis Swiss turning machines, enabling the part to be produced in a single operation and eliminating secondary operations.
Faster Speed, Fewer Steps
Robotic equipment manufacturers are busy developing machines that can further automate the machining process, such as the high-precision loading multiple pieces of equipment with raw materials or parts, reducing or eliminating human error.
“Advances in software and automated programming now facilitate ‘end to end’ part processing, in a single step,” said Duane Audette, director of business development for Elk River, Minn.-based Metal Craft and Riverside Machine and Engineering Inc. (in Eau Claire, Wis.), providers of precision machining services. “For example, automatic loading of a part from a bar feed to a mill turn to the completed part tray. Enhancements in ‘dummy proofing’ the production process, such as tool break detection and auto probing, also prevent parts from being misloaded and reduces scrap costs.”
For bar grinding and polishing, improvements in grinding and polishing wheels have increased feed rates and improved size and polishing consistency. Advancements in Swiss machining technology include increased size capability and the continued integration of computers and automation, creating machining options that were not available as recently as two years ago.
“We have observed advancements in machining and tooling that allow for faster cycle times, improved throughput rates and new capabilities for users that have embraced and invested in technology,” said Dave Simak, marketing manager for Banner Service Corporation, a Carol Stream, Ill.-based supplier of precision ground bar, centerless grinding, turning and straightening. “Profiles and shapes that required multiple machining operations can now be done with one machine.”
“The continued addition of true five-axis machining allows OEMs to create flexible, innovative processes,” added Michael Minton, advanced technology manager at Methods Machine Tools, a Sudbury, Mass.-based supplier of high-precision machine tools and solutions. “The biggest change we have seen is with additive manufacturing—creating the ability to produce net or near-net shapes that require minimal machining to complete.”
What OEMs Want
OEMs are demanding more from their suppliers in terms of having total quality control in-house. They tend to prefer suppliers that can perform all critical machining in one location, under one roof, with a high-level quality control plan in place for all operations. Contract manufacturers that can manage the entire supply chain—from sourcing the product to providing complete or near net parts—have an advantage over the competition.
“Single-source/one-stop shopping reduces supply chain complexity and mitigates risk for many OEMs that have opted to outsource production,” said Simak. “In the medical industry, many implant type products are custom/one-off units that are tailored to meet an individual’s needs. The ability to have multiple machining capability, combined with superior-quality control systems, makes any given contract manufacturer more attractive to OEMs.”
In the medical industry, OEMs tend to reach out to suppliers for gun drilling, heat treating and surface treatments, plating, polishing and precision-turning of parts—specialty operations that are capital-intensive.
“The challenge comes in that there may be small volumes with a high mix of different products that need to be supplied in a timely fashion,” said Simak. “Therefore, companies that are investing in the latest machine tool technology often position themselves well, due to the flexibility and capability brought on by new equipment.”
As they develop smaller and more complex products with tight tolerances and tough-to-machine materials, OEMs are eager to maximize productivity, reduce scrap, and maintain very tight run-out, diameter, true position and cylindricity specifications.
“This means that research and development in the cutting tool sector is paramount to staying competitive in the fast-paced medical field,” said Jeff Augustine, director of new business development for Drill Masters Eldorado Tool, a Milford, Conn.-based supplier and manufacturer of deep hole gun drilling tools, fixtures and accessories.
To achieve these tight tolerances, specialized tooling often is required, such as solid carbide gun drills as small as 1 millimeter (.03937 inches) in diameter, with depth-to-diameter ratios that far exceed conventional twist drills. These carbide drills require no pecking or dwelling.
“These gun drills are used for making the holes that go through surgical bone screws and bone reamers,” said Augustine. “The surgeon uses these holes to guide wires during surgery. All of the holes in these parts are drilled with solid carbide gun drills from materials ranging from 17-4 stainless to 6AL4V titanium, which are preferred by our customers because of their strength.”
Advanced Technologies
Computer numerical control (CNC) machining continues to evolve, reducing tooling costs and lead times. The biggest advantage new machines have today is the ability to change designs quickly with fewer setups, switching quickly from one part to another. This typically improves cycle times. Often, a part can be completed from beginning to end on one machine center, eliminating time-consuming secondary operations on different machines.
Multi-axis Swiss machines also can machine complex shapes and features with high precision and consistency. Computers and automation currently are being integrated directly into the work benches and cells of Swiss machining centers, providing additional flexibility.
“The machine operator is now an integral part of the layout, machine programming and statistical control process,” said Simak. “Automation allows for lights-out operation and extends capacity for companies looking to continue production after the standard work day has ended. Swiss machines now have the capability to perform multiple operations that used to require removal of the part, with transfer to a different operation. Secondary operations that were commonly performed on lathes and other machining centers can all be done in process as a result of advancements in tooling and automation.”
Spindle temperature control also is available on some machines and can enhance the micromachining performance (coolant flows through the machine spindle and through the drill, evacuating at the tip and flushing the chips down the straight flute)—cooling it directly from the inside). This allows increased use of gun drilling.
“The biggest misconception about gun drilling is that it cannot be performed on any other machine other than a dedicated gun drill machine,” said Augustine. “Virtually any machine—including screw machines, machining centers, and CNC lathes—that have spindle high pressure coolant capabilities are utilizing and incorporating gun drilling in their process, thus eliminating secondary operations on specialized machines.”
In the past, parts first were machined on specific machines and then taken to a gun drill machine for the hole to be produced, and then sometimes returned to another machine for specific operations. More versatile machines now have been designed or adapted to have spindle coolant capabilities to up to 1,000 pounds per square inch and greater, which allows gun drilling of holes as small as .0350 inches, to depths per print and in a single setup.
“If a company uses gun drilling on a screw machine, machining center or CNC lathe, instead of using a dedicated gun drill machine, the cost savings could be as much as $100,000 to $200,000 for a machine, time and cost to drill,” said Augustine. “These improvements can result up to one minute off the cycle time, which is huge.”
Improvements in grinding and polishing wheels allow for faster feed rates, reduced passes (to remove more material in a given pass), and improved size and polishing consistency over the length of the bar. “This allows us to maintain O.D. (outer diameter) tolerances of +/- .0001 inches consistently along the length of the bar, without sacrificing speed and surface finish,” said Simak. “For certain medical applications, we have been able to maintain +/- .00005 inches over the length of the bar.”
For water-jet cutting, the latest equipment provides multiple cutting heads that allow more than one piece to be cut during the cycle. In addition, advancements in computer software and sensing technology provide tighter tolerances, allowing complex shapes that could not be water-jet cut as recently as two years ago.
Innovation in Action
Controlling heat in a thin-walled part during drilling is always a challenge because longer parts naturally want to bend. Gun drilling this kind of part may require counter rotation, specialized nose geometry or a coolant chiller. Drilling parts with holes very close together requires specific techniques because, with thin walls, the drill wants to follow the path of least resistance, which is where the heat is located. This results in inconsistent run-out. The solution is drilling every other hole, and then going back and drilling the missed ones, keeping the wall thickness between each hole equal and run-out consistent. Longer carbide heads enable drilling through voids and intersecting holes while using the exit hole as a pilot while entering the opposite side.
Other parts require multiple stepped diameter holes—which in the past would have required several passes to produce.
“With the latest gun-drilling equipment, we can engineer, design and manufacture stepped drills that can produce these holes in a single pass, providing eccentricity between diameters close to zero,” said Augustine. “This equates to less machine time, reduced scrap and significant savings to our customers.”
Seven-axis grinding can eliminate the need for five-axis, 3-D profile milling on parts that can incorporate the deburring and finishing processes in a single operation.
“This has greatly reduced the lead time and increased the throughput for the OEM,” said Audette. “In our facilities, robotically fed electric discharge machining (EDM) and mill-turns and seven-axis CNC grinding are our most innovative areas of machining and tooling. We also utilize pallet changing horizontals and automate the finishing processes as much as possible.”
Methods Machine Tools recently was challenged by a customer to make a complete component in one machine from heat-treated material, while reducing cycle time 30 percent.MMT engineers selected a Nakamura Model NTMX machine for the project.
“This is a standard machine offering from Nakamura and has a B-axis milling head, providing the ability to generate complex geometries in a single platform,” said Minton.“The material was 17-4 Ph stainless [steel] heat treated to approximately 45 Rc (part of the Rockwell scale for measuring hardness).Custom tools had to be designed and manufactured. When completed, we had reduced the part cycle time by 36 percent.”
Another trend Minton has noticed is the push by OEMs to create patient-specific implants.The OEM typically will generate a model of the patient-specific implant and use this data to produce the specific implant.
“We developed a system utilizing a four-axis, high-precision vertical milling machine, coupled with a wire EDM machine, to produce the implant,” he said. “The EDM process virtually eliminated all the stress that would have normally been introduced during the machining process.This drastically reduced the machining cycle time and inherently stabilized the machining process.”
Banner Medical often works with OEMs to solve problems associated with the in-house manufacture of components. A big issue for OEMs is not receiving material that consistently meets their specification for straightness, final diameter and surface finish. As a result, in-house machining performed by the OEM may result in extended machining times, high scrap rates and quality issues, which extend delivery times.
“To help solve these issues, Banner reviews the entire supply chain and offers raw material solutions to minimize these issues,” said Simak. “We can also work with OEMs to provide a near net shape, or even the complete part, that will meet their requirements, providing a single-source solution.”
Another material challenge is machining heat-treated materials—more manufacturers want to use materials that already are heat-treated to final specifications.
Machining these materials requires very rigid machine tools and cutting tools with geometries and coatings specific to the material and its condition.
“For example, a more rigid and geometrically accurate machine will provide dramatically increased tool life, while producing a more dimensionally accurate part with a better surface finish,” said Minton.“Additionally, the machine will provide consistent, predictable results for a much longer period of time.This ultimately reduces cost. As we start to machine more materials post heat treatment, the addition of MQL (minimum quantity lubricant) systems is proving invaluable to enhancing and increasing tool life.These systems are a significant improvement to traditional coolant systems.”
As new grades of super alloys and raw materials evolve, the tooling used to machine a given component also must evolve. Tooling must have increased hardness and durability to withstand the next generation of raw material.
“Having tooling that can last and cut parts to specification over extended periods will be a key factor for contract manufacturers and precision machine shops,” said Simak.
Sharing the Knowledge
Many OEMs have outsourced the majority of manufacturing to contract manufacturers and precision machine shops that specialize in machining various products for the medical industry. As a result, their engineers and designers are not as familiar with the latest advances in machining and tooling, or what is feasible when it comes to machining the products they are envisioning.
Audette indicates that the newest generations of engineers coming into the orthopedic industry don’t always realize that, just because a design can be modelled in CAD, it also can be viably manufactured at a marketable cost.
“We always offer alternatives to these situations to help our customers as they grow, and to keep their designers informed about best machining practices, in a collaborative way,” he said.
Equipment manufacturers tend to know the latest about what the orthopedic market is looking for and can design and manufacture machining solutions to meet those needs. They then share this knowledge with trusted contract manufacturers and machinists, thereby strengthening their positions in the supply chain.
For example, by implementing the latest grinding and polishing wheel technologies, Banner has been able to provide OEMs with faster feed rates, improved productivity and superior quality. To further share this knowledge, “we also pursue partnerships with contract manufacturers and precision machine shops with a wide variety of capabilities,” said Simak.
“OEMs continue to push hard for year-over-year cost reductions, as wages and costs to manufacture continue to increase,” said Audette. “This creates real challenges that we have been able to turn into opportunities for innovation and efficiency, without sacrificing quality and service. Finding ways to do more with less is vital for staying competitive in a world market.”
Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. 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.
Orthopedic OEMs, therefore, are eager to work with creative machine shops that can figure out how to streamline operations, such as using single setups and eliminating secondary operations. Quick changeovers and fewer machining/tooling steps are essential for optimizing throughput and time to market. Advanced five- and seven-axis milling machines have the capability to complete complex orthopedic designs in a single operation, including parts or products with complex geometry. For example, multiple functions such as milling, gun drilling and thread whirling can be completed at different stations on multi-axis Swiss turning machines, enabling the part to be produced in a single operation and eliminating secondary operations.
Faster Speed, Fewer Steps
Robotic equipment manufacturers are busy developing machines that can further automate the machining process, such as the high-precision loading multiple pieces of equipment with raw materials or parts, reducing or eliminating human error.
“Advances in software and automated programming now facilitate ‘end to end’ part processing, in a single step,” said Duane Audette, director of business development for Elk River, Minn.-based Metal Craft and Riverside Machine and Engineering Inc. (in Eau Claire, Wis.), providers of precision machining services. “For example, automatic loading of a part from a bar feed to a mill turn to the completed part tray. Enhancements in ‘dummy proofing’ the production process, such as tool break detection and auto probing, also prevent parts from being misloaded and reduces scrap costs.”
For bar grinding and polishing, improvements in grinding and polishing wheels have increased feed rates and improved size and polishing consistency. Advancements in Swiss machining technology include increased size capability and the continued integration of computers and automation, creating machining options that were not available as recently as two years ago.
“We have observed advancements in machining and tooling that allow for faster cycle times, improved throughput rates and new capabilities for users that have embraced and invested in technology,” said Dave Simak, marketing manager for Banner Service Corporation, a Carol Stream, Ill.-based supplier of precision ground bar, centerless grinding, turning and straightening. “Profiles and shapes that required multiple machining operations can now be done with one machine.”
“The continued addition of true five-axis machining allows OEMs to create flexible, innovative processes,” added Michael Minton, advanced technology manager at Methods Machine Tools, a Sudbury, Mass.-based supplier of high-precision machine tools and solutions. “The biggest change we have seen is with additive manufacturing—creating the ability to produce net or near-net shapes that require minimal machining to complete.”
What OEMs Want
OEMs are demanding more from their suppliers in terms of having total quality control in-house. They tend to prefer suppliers that can perform all critical machining in one location, under one roof, with a high-level quality control plan in place for all operations. Contract manufacturers that can manage the entire supply chain—from sourcing the product to providing complete or near net parts—have an advantage over the competition.
“Single-source/one-stop shopping reduces supply chain complexity and mitigates risk for many OEMs that have opted to outsource production,” said Simak. “In the medical industry, many implant type products are custom/one-off units that are tailored to meet an individual’s needs. The ability to have multiple machining capability, combined with superior-quality control systems, makes any given contract manufacturer more attractive to OEMs.”
In the medical industry, OEMs tend to reach out to suppliers for gun drilling, heat treating and surface treatments, plating, polishing and precision-turning of parts—specialty operations that are capital-intensive.
“The challenge comes in that there may be small volumes with a high mix of different products that need to be supplied in a timely fashion,” said Simak. “Therefore, companies that are investing in the latest machine tool technology often position themselves well, due to the flexibility and capability brought on by new equipment.”
As they develop smaller and more complex products with tight tolerances and tough-to-machine materials, OEMs are eager to maximize productivity, reduce scrap, and maintain very tight run-out, diameter, true position and cylindricity specifications.
“This means that research and development in the cutting tool sector is paramount to staying competitive in the fast-paced medical field,” said Jeff Augustine, director of new business development for Drill Masters Eldorado Tool, a Milford, Conn.-based supplier and manufacturer of deep hole gun drilling tools, fixtures and accessories.
To achieve these tight tolerances, specialized tooling often is required, such as solid carbide gun drills as small as 1 millimeter (.03937 inches) in diameter, with depth-to-diameter ratios that far exceed conventional twist drills. These carbide drills require no pecking or dwelling.
“These gun drills are used for making the holes that go through surgical bone screws and bone reamers,” said Augustine. “The surgeon uses these holes to guide wires during surgery. All of the holes in these parts are drilled with solid carbide gun drills from materials ranging from 17-4 stainless to 6AL4V titanium, which are preferred by our customers because of their strength.”
Advanced Technologies
Computer numerical control (CNC) machining continues to evolve, reducing tooling costs and lead times. The biggest advantage new machines have today is the ability to change designs quickly with fewer setups, switching quickly from one part to another. This typically improves cycle times. Often, a part can be completed from beginning to end on one machine center, eliminating time-consuming secondary operations on different machines.
Multi-axis Swiss machines also can machine complex shapes and features with high precision and consistency. Computers and automation currently are being integrated directly into the work benches and cells of Swiss machining centers, providing additional flexibility.
“The machine operator is now an integral part of the layout, machine programming and statistical control process,” said Simak. “Automation allows for lights-out operation and extends capacity for companies looking to continue production after the standard work day has ended. Swiss machines now have the capability to perform multiple operations that used to require removal of the part, with transfer to a different operation. Secondary operations that were commonly performed on lathes and other machining centers can all be done in process as a result of advancements in tooling and automation.”
Spindle temperature control also is available on some machines and can enhance the micromachining performance (coolant flows through the machine spindle and through the drill, evacuating at the tip and flushing the chips down the straight flute)—cooling it directly from the inside). This allows increased use of gun drilling.
“The biggest misconception about gun drilling is that it cannot be performed on any other machine other than a dedicated gun drill machine,” said Augustine. “Virtually any machine—including screw machines, machining centers, and CNC lathes—that have spindle high pressure coolant capabilities are utilizing and incorporating gun drilling in their process, thus eliminating secondary operations on specialized machines.”
In the past, parts first were machined on specific machines and then taken to a gun drill machine for the hole to be produced, and then sometimes returned to another machine for specific operations. More versatile machines now have been designed or adapted to have spindle coolant capabilities to up to 1,000 pounds per square inch and greater, which allows gun drilling of holes as small as .0350 inches, to depths per print and in a single setup.
“If a company uses gun drilling on a screw machine, machining center or CNC lathe, instead of using a dedicated gun drill machine, the cost savings could be as much as $100,000 to $200,000 for a machine, time and cost to drill,” said Augustine. “These improvements can result up to one minute off the cycle time, which is huge.”
Improvements in grinding and polishing wheels allow for faster feed rates, reduced passes (to remove more material in a given pass), and improved size and polishing consistency over the length of the bar. “This allows us to maintain O.D. (outer diameter) tolerances of +/- .0001 inches consistently along the length of the bar, without sacrificing speed and surface finish,” said Simak. “For certain medical applications, we have been able to maintain +/- .00005 inches over the length of the bar.”
For water-jet cutting, the latest equipment provides multiple cutting heads that allow more than one piece to be cut during the cycle. In addition, advancements in computer software and sensing technology provide tighter tolerances, allowing complex shapes that could not be water-jet cut as recently as two years ago.
Innovation in Action
Controlling heat in a thin-walled part during drilling is always a challenge because longer parts naturally want to bend. Gun drilling this kind of part may require counter rotation, specialized nose geometry or a coolant chiller. Drilling parts with holes very close together requires specific techniques because, with thin walls, the drill wants to follow the path of least resistance, which is where the heat is located. This results in inconsistent run-out. The solution is drilling every other hole, and then going back and drilling the missed ones, keeping the wall thickness between each hole equal and run-out consistent. Longer carbide heads enable drilling through voids and intersecting holes while using the exit hole as a pilot while entering the opposite side.
Other parts require multiple stepped diameter holes—which in the past would have required several passes to produce.
“With the latest gun-drilling equipment, we can engineer, design and manufacture stepped drills that can produce these holes in a single pass, providing eccentricity between diameters close to zero,” said Augustine. “This equates to less machine time, reduced scrap and significant savings to our customers.”
Seven-axis grinding can eliminate the need for five-axis, 3-D profile milling on parts that can incorporate the deburring and finishing processes in a single operation.
“This has greatly reduced the lead time and increased the throughput for the OEM,” said Audette. “In our facilities, robotically fed electric discharge machining (EDM) and mill-turns and seven-axis CNC grinding are our most innovative areas of machining and tooling. We also utilize pallet changing horizontals and automate the finishing processes as much as possible.”
Methods Machine Tools recently was challenged by a customer to make a complete component in one machine from heat-treated material, while reducing cycle time 30 percent.MMT engineers selected a Nakamura Model NTMX machine for the project.
“This is a standard machine offering from Nakamura and has a B-axis milling head, providing the ability to generate complex geometries in a single platform,” said Minton.“The material was 17-4 Ph stainless [steel] heat treated to approximately 45 Rc (part of the Rockwell scale for measuring hardness).Custom tools had to be designed and manufactured. When completed, we had reduced the part cycle time by 36 percent.”
Another trend Minton has noticed is the push by OEMs to create patient-specific implants.The OEM typically will generate a model of the patient-specific implant and use this data to produce the specific implant.
“We developed a system utilizing a four-axis, high-precision vertical milling machine, coupled with a wire EDM machine, to produce the implant,” he said. “The EDM process virtually eliminated all the stress that would have normally been introduced during the machining process.This drastically reduced the machining cycle time and inherently stabilized the machining process.”
Banner Medical often works with OEMs to solve problems associated with the in-house manufacture of components. A big issue for OEMs is not receiving material that consistently meets their specification for straightness, final diameter and surface finish. As a result, in-house machining performed by the OEM may result in extended machining times, high scrap rates and quality issues, which extend delivery times.
“To help solve these issues, Banner reviews the entire supply chain and offers raw material solutions to minimize these issues,” said Simak. “We can also work with OEMs to provide a near net shape, or even the complete part, that will meet their requirements, providing a single-source solution.”
Another material challenge is machining heat-treated materials—more manufacturers want to use materials that already are heat-treated to final specifications.
Machining these materials requires very rigid machine tools and cutting tools with geometries and coatings specific to the material and its condition.
“For example, a more rigid and geometrically accurate machine will provide dramatically increased tool life, while producing a more dimensionally accurate part with a better surface finish,” said Minton.“Additionally, the machine will provide consistent, predictable results for a much longer period of time.This ultimately reduces cost. As we start to machine more materials post heat treatment, the addition of MQL (minimum quantity lubricant) systems is proving invaluable to enhancing and increasing tool life.These systems are a significant improvement to traditional coolant systems.”
As new grades of super alloys and raw materials evolve, the tooling used to machine a given component also must evolve. Tooling must have increased hardness and durability to withstand the next generation of raw material.
“Having tooling that can last and cut parts to specification over extended periods will be a key factor for contract manufacturers and precision machine shops,” said Simak.
Sharing the Knowledge
Many OEMs have outsourced the majority of manufacturing to contract manufacturers and precision machine shops that specialize in machining various products for the medical industry. As a result, their engineers and designers are not as familiar with the latest advances in machining and tooling, or what is feasible when it comes to machining the products they are envisioning.
Audette indicates that the newest generations of engineers coming into the orthopedic industry don’t always realize that, just because a design can be modelled in CAD, it also can be viably manufactured at a marketable cost.
“We always offer alternatives to these situations to help our customers as they grow, and to keep their designers informed about best machining practices, in a collaborative way,” he said.
Equipment manufacturers tend to know the latest about what the orthopedic market is looking for and can design and manufacture machining solutions to meet those needs. They then share this knowledge with trusted contract manufacturers and machinists, thereby strengthening their positions in the supply chain.
For example, by implementing the latest grinding and polishing wheel technologies, Banner has been able to provide OEMs with faster feed rates, improved productivity and superior quality. To further share this knowledge, “we also pursue partnerships with contract manufacturers and precision machine shops with a wide variety of capabilities,” said Simak.
“OEMs continue to push hard for year-over-year cost reductions, as wages and costs to manufacture continue to increase,” said Audette. “This creates real challenges that we have been able to turn into opportunities for innovation and efficiency, without sacrificing quality and service. Finding ways to do more with less is vital for staying competitive in a world market.”
Mark Crawford is a full-time freelance business and marketing/communications writer based in Madison, Wis. 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.