ASK THE EXPERT
Joshua Jablons, PhD, is the Executive Vice President of Metal Cutting Corp., a specialty metal fabrication company in Cedar Grove, NJ. Jablons has worked in the metals business since 1987. During his career in the industry, he has specialized in three areas: the manufacture and metrology of tight tolerance parts, burr-free production techniques, and refractory metals. He earned his BA at Wesleyan University and his MA and PhD at New York University.
MPMN: How has the trend of miniaturization impacted the metal fabrication industry? Do you view this as a negative or positive trend for the field?
Jablons: Miniaturization has been an excellent trend so far for the metal fabrication industry. It has provided value-added challenges that producers have mostly met. Of course, not every part can be made- there is a saying amongst fabricators that "if you can draw it to scale, we can make it." However, when compared with the traditional smokestack approach to making railroad ties, creating value by proprietary techniques geared towards ever smaller parts, that additionally have a far more limited impact on the environment and also consume less energy during manufacturing, is a good thing.
MPMN: What changes may be necessary to accommodate the increasing demand for micromachining?
Jablons: The key here is the design of tooling. As the part dimensions shrink, the problem is not necessarily the metallurgy of the part. It is the ability to make a tool that can remove such a small amount of metal - that is machining after all - and also the tooling or fixture to hold the part that is to remain. Alternatives to traditional turning and grinding have their own challenges, so if you use chemical machining, you've still got to hold the tiny part and control the chemical reaction to the desired tolerances. Not that these and other methods can't do the job - in fact, they often can - but they all have their challenges, and the proprietary value consists of figuring out the changes needed to make your particular approach work.
MPMN: Which metals are most difficult to work with? Why?
Jablons: Again, the key here is tooling. Everyone knows about the hard metals that immediately dull a seemingly hard tool, but in terms of being difficult, if you use a self-dressing tool to work soft material, that tool will "load" and will be rendered as useless as the prior example. With the correct tools, all metals can be worked -- although the point is well taken if posed as cost. Harder metals typically require more expensive tools. For example, carbides, which require diamond tools to be worked, are therefore amongst the most difficult to work in financial terms.
MPMN: What role does the threat of corrosion play in metal fabrication processes?
Jablons: It plays a significant role in two ways. First, metal parts that are subject to a corrosive or oxidizing chemical reaction must be protected both during manufacturing and in transit to the customer. This protection can be simple (but messy) such as a coat of oil used in the low carbon steel industry. This example is to illustrate the issue, although the medical device industry doesn't usually work with such metals and almost never accepts parts coated in oil. Other protective techniques such as anodizing are obviously difficult to remove. The other problem posed by corrosion is to the manufacturing equipment itself. It is difficult to hold tight tolerances on parts if the components of the machine producing the parts are not correctly aligned due to a corrosive reaction. On the other hand, the threat of corrosion is a terrific opportunity for those manufacturers of metals that resist the particular corrosion problem encountered.
MPMN: Metal fabrication is known for generating a lot of waste. What are the most common waste-reduction or recycling methods for medical metal fabrication? Are they effective?
Jablons: I recall that when I began in the industry "tri-chlor" was being phased out for cleaning parts "spot-free" and chemical coolants were often still used. The former is famously bad for the ozone layer and the latter is harmful to both human operators and is also a disposal hazard. Now there are many spotless cleaners that are environmentally benign. The trend towards greater precision has also meant that important parts of machines are often made from carbides and therefore using plain water as a coolant is not a problem. Another benefit of miniaturization is that the parts are getting smaller, so when compared with the environmental impact and energy consumed making structural metal, medical device metal fabricators produce far less waste and the waste is far easier to manage and clean.
MPMN: The rise of biocompatible ceramic components and the exploration of nanotechnology indicate that other materials may replace metal in many medical applications. How might this affect the metal fabrication industry?
Jablons: Metal fabrication means two different activities. First the metal itself is fabricated. Second the part is fabricated from the metal. In the first sense, as the fabrication of ceramics is essentially similar to powder metallurgy, that relatively small group of metal fabricators who use powder metallurgy technology - and this includes refractory metal producers - can benefit from any market share shift from metals to ceramics. In the second sense, metal fabricators who have the ability to machine ceramics - and it is not a simple transition - can also be protected as the market shifts. However, when customers replace a metal part with a ceramic or plastic one, it is generally not good for either type of metal fabricator.Nanotechnology is a paradigm shift from removing a substance that reveals the shape of a part to the building of the part at the molecular level. While metal injection molding and certain deposition techniques may be considered remotely similar in concept, there is no meaningful overlap between nanotechnology and current metal fabrication. For example, an SEM image of a metal part showing dimensions in nanometers is not nanotechnology. Even if the dimensional tolerances of the part are repeatable at a nanometer scale - which is achievable in only a limited set of dimensional circumstances - the methods of fabrication to make that part has nothing to do with the molecular assembly of nano structured materials. Ultimately, as miniaturization reaches the nanometer scale, metal fabrication as is now practiced will lose market share.
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