Thursday, September 20, 2012

Increasing demand provides challenges for micro machining

Increasing demand provides challenges for micro machining

 
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:
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.


Sunday, September 2, 2012

Our Services - Miniature Machining

 

Our Services - Miniature Machining

Our Services

Core Pin Machine ShopGrinding
Ay-Mac Precision is unique in the core custom pin manufacturing trade. Our combination of machining and grinding expertise sets us apart from our competition.
Form Grinding
Grinding forms on round core pins between centers is our specialty. Our cylindrical grinders are capable of holding tolerances as close as .0001 on quantities from one piece to thousands with surface finishes of 12 RMS.. The small size of our O.D. grinders, about half the size of a tool room grinder, make them very fast to set up and operate. This enables us to produce core pins very economically and pass the savings along to our customers. The pictures you see on our home page are just a small example of the type of work we have done in our 25 years of grinding custom core pins.
Centerless Grinding
We have 5 centerless grinders with wheel widths from 2" to 8" .Tolerances as close as .0001 with surface finishes of 12 RMS are held routinely. The centerless grinders are an integral part of the core pin making process and are used in conjunction with the O.D. grinders to economically produce a finished part . We have run large production runs with diameters as small as .008.
Surface Grinding
We have 12 surface grinders which we use to finish the core pins. They are typically used for finishing the ends of the core pins. They are also used for putting vent flats, slots, radii, angles, head relief or any other requirements our customers specify. We also make custom ejector blades with tolerances of +/- .0001.
Machining
We have a variety of standard machine tools and many custom built machines which enable us to be extremely competitive while still maintaining the quality our customers require.
Consulting
With our experience in manufacturing core pins, our customers often consult us to discuss and critique their design. We happily offer design advice with the intent to reduce the cost to the customer, plus improve the life and production performance of the pins.
Delivery
Our standard lead time is four weeks ARO, but urgent requests for quick turnaround will get the attention and response requested by our customers.

Minature Precision Machining Services We Provide