We Know Subtraction, Should We Learn Addition?

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Since the dawn of metalworking, machining raw material has been a subtractive process. One takes a blank of material and, using a variety of tools, removes all of the excess material necessary to reveal a desired finished shape.

The material is, well, immaterial, because the process of subtractive manufacturing works on pretty much anything from stone to wood to our favorite—metal. In metalworking, a result of this age-old processing technology is a barrel full of chips that can be recycled into more blanks. It’s a beautiful thing that continues to sustain our industry.

However, our comfortable subtractive apple cart may be being upset by upstarts peddling a notion called additive manufacturing. And there is evidence that it is time to consider a look-see at what these additive folks are talking about.

Additive manufacturing (AM) goes by several names. These include the technologies and processes involving stereolithography, 3D printing, fused deposition modeling, selective laser sintering and the materials, scanners and software needed to manufacture parts in both prototype and production quantities.

Regardless of what it’s called, the process is the same. Instead of removing material to expose a desired shape, AM deposits thin layers of various materials in precise CAT-scan like slices.

A binder holds each layer to the next and previous and several methods, such as heat and chemicals, are used to create the desired 3D part. Materials used for each slice can be paper, plastic and metals. Sintering the laid-up metals creates a workable part that, depending on the metals, can be used in an application. 

According to David Burns, president and COO of The Ex One Company, “Through the diligent work of a variety of companies and research institutions, the speed, the variety of materials available, the dimensional characteristics and application areas for AM have improved exponentially over the last few years. Basically, what was a relatively expensive and esoteric process only a few years ago is being re-examined closely by companies looking to make exactly what they need, when it is needed, where it is needed while eliminating non-value added steps between conceptualization and creation.” 

As I am writing this column in mid-August, word was released yesterday from President Obama’s administration that a consortium of regional businesses, universities and nonprofit organizations has been awarded $30 million by the Departments of Defense and Commerce to establish the National Additive Manufacturing Innovation Institute (NAMII). The participants will comprise a core group of companies and institutions throughout Northeast Ohio, Pennsylvania and West Virginia.

The participating companies have pledged to match the government funds with an additional $40 million, and its headquarters will be established in Youngstown, Ohio. Now, I can hear some of you mumbling about politics, election year stunts, battleground states’ electoral votes and other less than flattering motivations for this initiative. Hopefully, the effort is a genuine one to help recognize the need for continued research and development of promising new technology so American manufacturers can keep the momentum we’ve experienced in the past few years going forward.

I talk to many makers of subtractive manufacturing equipment, and all of them are looking at the emergence of AM. They do not see it as a threat, but rather as an opportunity to be involved in a new way of manufacturing that seems to have legs for some applications.    

Subtractive and additive should not be considered competitive processes. It is not a zero-sum game where if additive manufacturing is used, subtractive manufacturing takes a hit. We’ve seen so-called threats before, and the reality is always co-existence that leads to expansion of the industry overall.

In the case of additive and subtractive manufacturing, they actually have co-existed for millennia, just in different arenas. Think of a museum featuring painting (an additive process) sitting alongside sculpture (a subtractive process). They complement each other and make the world a better place for it.

That’s how I see additive and subtractive manufacturing. Each is a means to an end; adding value to a less valuable raw material, which is the very definition of manufacturing.

As Mr. Burns said in a column published in PM last year, “If manufacturing parts in an industrial environment is part of your life, then it would be wise to anticipate that AM will be part of your life.”

Visit the additive manufacturing zone at mmsonline.com/zones/additive for more information.