ISE Magazine February 2019 Volume: 51 Number: 2
By Matt Sand
The notion that manufacturing and environmental health are at odds has been commonly held since the environmental movement really got going in the 1960s. Most of the time, this characterization has been true. There really is an environmental trade-off associated with industrial activity, at least in the traditional sense. Among the most damaging of these effects are:
- Huge energy demands, typically met with fossil fuels, associated with fabrication and shipping
- Material waste due to inefﬁcient usage of materials. Computer numerical controlled (CNC) milling can generate as much as 95 percent waste
- Air, water, and soil quality impacts when toxic substances associated with production ﬁnd their way into the area surrounding a factory
- Sub-optimal designs that result in unnecessarily heavy or inefﬁcient products that, in turn, generate waste
The economic benefits of making metal additives as an alternative to traditional methods are clear, but the reduced environmental impact may be even more important for the future of the industry. Each of the four environmental weaknesses of conventional manufacturing listed above has the potential to be reduced, or even improved, by 3D printing. The following is how AM metal can help overcome environmental problems caused by traditional techniques.
Shipping leaves enormous carbon footprint
The flow of raw materials into manufacturing facilities and finished goods from there requires enormous energy inputs allocated for shipping. Given that traditional manufacturing has relied heavily on fossil fuels since the Industrial Revolution, this process has caused huge losses to the environment.
3D printing cannot solve all these problems, but has the potential to dramatically cut the number of links in the chain by allowing the creation of various local components on demand. The day is getting closer when large domestic producers do not need to take part of special facilities abroad. Every component of the product that can be produced in a location is very influential to reduce the carbon footprint of the product. Without a doubt, 3D printing will eliminate millions of component delivery trips in the coming decade.
Traditional processes waste vital resources
The largest segment of the metal parts fabrication industry is “subtractive” processes like CNC milling, in which material is cut away from a block to produce a ﬁnal part, the problem of this manufacturing type is that any of the original block of metal that is cut away is waste. That wasted material represents additional resources that must be extracted from the earth via potentially harmful mining practices.
Even worse, the ﬁnal outcome for the scrap material itself involves one of two things: additional shipping and processing to take advantage of whatever economic value the cast-off still has and a trip to the local landﬁll
Metal 3D printing, when economically viable, provides a nearly perfect solution to this problem. Because it’s an additive process, whereby material is layered onto itself in an exact pattern, there is virtually no waste associated. Only the metal that actually constitutes the ﬁnal component is used. The unused material can be recycled.
This could mean the difference between 95 percent waste with CNC machining and less than 1 percent waste using metal AM.
Toxic byproducts are common in metal manufacturing
Pollution has many forms. Carbon dioxide emissions deserve a lot of attention from environmentalists, but other types of pollution also cause a lot of damage. CNC machining and metal injection molding, requires the use of toxic substances as part of the process. Oils and lubricants are needed to ensure that CNC machines work well harmful to the environment.
Metal AM eliminates this concern entirely. The process simply doesn’t generate any toxic byproducts, which guarantees that air and water quality won’t be directly harmed. Conventionally made components can leave a much bigger carbon footprint than 3D printed parts.
Although it may seem rather unfair to compare 3D printed parts with those produced by techniques that have existed for hundreds of years, this section is a new standard to produce increased efficiency, the biggest leap occurs in one area: part consolidation.
Lessening carbon footprint through AM-enabled design
3D printing allows for the manufacture of parts with complex internal geometries. The upshot is that design changes that combine multiple parts into a single component can often be completed without sacriﬁcing functionality or feasibility. This accomplishes the goal of lowering cost and lead times by simplifying the manufacturing process, but it also comes with signiﬁcant environmental advantages. To date, the most impressive example of this type of part consolidation comes from General Electric.
The key to this extraordinary set of characteristics lies in the sophisticated simplicity of turboprops. With advanced turboprops, GE took a design that initially called for 855 engine components and released them into 12 clean and beautiful parts that retained all functions, and many more, old models. These changes make significant cuts to the weight and cost of production.
However, more important savings can cut emissions dramatically. The company estimates that new machines produce 10 percent more power and cut fuel use by 20 percent. The implications of such a reduction are being refined by the GE scale: The company’s technology has empowered most of all airlines.
Additive manufacturing optimizes designs, efﬁciency
As the world marches toward an increasingly tenuous cli-mate future, the costs of a suboptimal part made through traditional manufacturing must be considered alongside the more tangible impacts described above. There are countless heavy or less-than-aerodynamic components in applications across every sector that could be improved signiﬁcantly with the design freedom afforded by metal AM.
In aggregate, the emissions reductions that are now feasible through projects like GE’s Advanced Turboprop engine would represent major improvements for humanity’s overall carbon footprint.
Metal 3D printing doesn’t yet offer all the answers, but in a growing percentage of manufacturing situations, it’s a step in the right direction for our planet.
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