The increasing interest in micro-machining technology has captured the imagination of many manufacturing and industry segments, such as aerospace, medical, automotive. While the potential for product miniaturization continues to grow it also poses numerous technical challenges.
Micro machining simply means small or miniature to many of us in manufacturing.
While manufacturing miniature parts isn't new, the difference today is an increase in shear volume of products that require micro machining. Many manufacturers’ are developing and expanding their micro machining technologies and techniques to keep up with this demand.
In some cases, companies are looking for parts with some demensions less than 100 microns, or slighty larger than a human hair.
At this scale, the most slight variation in the manufacturing process, which could be caused by material or cutting tool characteristics, thermal variations, vibration, or any number of minute changes could have have an immediate affect on the ability to manufacture such specs on any useful production scale.
Companies are developing new methods and technologies to meet these micro manufacturing challenges.
There are several key areas where machining details this small bring up concerns:
Due to their cumulative-error effect, a good rule of thumb is that the systems used in manufacturing should be 10 times more accurate than the repeatable tolerance specified.
For instance, in environmental conditions, simply monitoring the room is not enough. There can be structural changes caused by temperature variations which stem from the mass of the machine. Additionally this rate of change will vary from system to system based on mass. For this reason, it makes sense to house and maintain the machine in its own controlled environment, a thermal enclosure.
Another example is the fact that any variation in axis position during the cut can be disastrous. The spindle must be stable, with minimized tool change variation and vibration. Any vibration will adversely influence the surface finish and accuracy. Added to this is the is the amount of force associated with removing material at the particulate level.
One solution developed several years ago was using a direct tool-change type spindle. Eliminating the tool holder made it possible to reduce total run-out caused by tool holder variation. This is also ideal in eliminating stack-up issues.
Micron and even sub-micron manufacturing requirements having continued growth offers unique challenges and wide opportunities to a large group of manufacturers. The various designs and construction of many machine tools, work and tool holders, cutting tools and electrodes will continue to evolve. This due to the greater demands placed on them when machining miniature and sub-miniature parts.
While many of the challenges will evolve around economically controlling the micro manufacturing process, it's plain that many of these systems would'nt have been developed without the demands of industry for greater capability and prodution capacity.
The lathes and mills themselves are much smaller in size, which leaves some shops skeptical about their ability to resist vibration. Traditionally, a machine tool’s quality was gauged by its weight, with heavier being better. The base and column of some of these smaller machines are now cast from a proprietary granite co-polymer composite. The composite appears to offer eight times the vibration damping characteristics of traditional cast iron. This enables the smaller machines to provide performance characteristics matching those of much heavier machines.
Beyond the challenges of actually machining such small parts, it's been observed that most customers struggle to even hold them. So work-holding becomes a key part of the whole micro-machining work flow.Wil the lower cutting forces involved somewhat moderate required rigidity, gripping tiny parts still remain a problem.
One idea has been to provide robotic workhandling systems to simplify work flow. In such an application, a robot picks parts from a tray and moves them to pneumatic grippers on the machine,where they are positioned for machining. When that cycle is complete, the robot then removes the parts from the machine - placing them in a finished parts tray.
Again, it's the demand for smaller and smaller mass-produced items which is driving the growth of this industry sector. As long as there is demand which can be met economically, innovation will continue to reward companies that can produce the quality needed in the volume required.
Micro machining simply means small or miniature to many of us in manufacturing.
While manufacturing miniature parts isn't new, the difference today is an increase in shear volume of products that require micro machining. Many manufacturers’ are developing and expanding their micro machining technologies and techniques to keep up with this demand.
In some cases, companies are looking for parts with some demensions less than 100 microns, or slighty larger than a human hair.
At this scale, the most slight variation in the manufacturing process, which could be caused by material or cutting tool characteristics, thermal variations, vibration, or any number of minute changes could have have an immediate affect on the ability to manufacture such specs on any useful production scale.
Companies are developing new methods and technologies to meet these micro manufacturing challenges.
There are several key areas where machining details this small bring up concerns:
1. Accuracy impacted by environmental changes
2. Process predictability and repeatability
3. Both internal and external vibration
4. Fluid dynamics to do with cutting fluids
It becomes obvious that maintaining control of all of the machining variables, which are a given in larger machines proceses, become more pronounced at micro-levels. These include the machine tool, work and tool-holding, the environment, cutting tools or electrodes. All will have a huge cumulative effect on the end result.Due to their cumulative-error effect, a good rule of thumb is that the systems used in manufacturing should be 10 times more accurate than the repeatable tolerance specified.
For instance, in environmental conditions, simply monitoring the room is not enough. There can be structural changes caused by temperature variations which stem from the mass of the machine. Additionally this rate of change will vary from system to system based on mass. For this reason, it makes sense to house and maintain the machine in its own controlled environment, a thermal enclosure.
Another example is the fact that any variation in axis position during the cut can be disastrous. The spindle must be stable, with minimized tool change variation and vibration. Any vibration will adversely influence the surface finish and accuracy. Added to this is the is the amount of force associated with removing material at the particulate level.
One solution developed several years ago was using a direct tool-change type spindle. Eliminating the tool holder made it possible to reduce total run-out caused by tool holder variation. This is also ideal in eliminating stack-up issues.
Micron and even sub-micron manufacturing requirements having continued growth offers unique challenges and wide opportunities to a large group of manufacturers. The various designs and construction of many machine tools, work and tool holders, cutting tools and electrodes will continue to evolve. This due to the greater demands placed on them when machining miniature and sub-miniature parts.
While many of the challenges will evolve around economically controlling the micro manufacturing process, it's plain that many of these systems would'nt have been developed without the demands of industry for greater capability and prodution capacity.
The lathes and mills themselves are much smaller in size, which leaves some shops skeptical about their ability to resist vibration. Traditionally, a machine tool’s quality was gauged by its weight, with heavier being better. The base and column of some of these smaller machines are now cast from a proprietary granite co-polymer composite. The composite appears to offer eight times the vibration damping characteristics of traditional cast iron. This enables the smaller machines to provide performance characteristics matching those of much heavier machines.
Beyond the challenges of actually machining such small parts, it's been observed that most customers struggle to even hold them. So work-holding becomes a key part of the whole micro-machining work flow.Wil the lower cutting forces involved somewhat moderate required rigidity, gripping tiny parts still remain a problem.
One idea has been to provide robotic workhandling systems to simplify work flow. In such an application, a robot picks parts from a tray and moves them to pneumatic grippers on the machine,where they are positioned for machining. When that cycle is complete, the robot then removes the parts from the machine - placing them in a finished parts tray.
Again, it's the demand for smaller and smaller mass-produced items which is driving the growth of this industry sector. As long as there is demand which can be met economically, innovation will continue to reward companies that can produce the quality needed in the volume required.
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