The magic of 3D printing – I

Anyone with integrity or who knows what she is talking about will hardly fight the statement that technological advancement is synonymous with human civilization. For a proof of this, for a moment, take away automobiles, airplanes, space vehicles, electric power generation equipment, computers, phones, mechanized farming (agricultural) equipment; heating, ventilating, and air-conditioning equipment; biomedical engineering […]

Anyone with integrity or who knows what she is talking about will hardly fight the statement that technological advancement is synonymous with human civilization. For a proof of this, for a moment, take away automobiles, airplanes, space vehicles, electric power generation equipment, computers, phones, mechanized farming (agricultural) equipment; heating, ventilating, and air-conditioning equipment; biomedical engineering innovations, modern manufacturing techniques, and the establishment of codes and standards, and you will, in a minute, catapult the entire human race back into the stone ages. Thus, we owe a lot to technology and engineering – which, in turn, are made possible by science and mathematics. We also owe to business, the social sciences, and the arts, for mass adoption and helping humans interact with the inventions.
3D printing is already making waves, at least in perception, if not in actually turning production on its head. As are most of the inventions listed above, 3D printing is within the purview of mechanical engineering, and specifically, manufacturing.
The business world has acknowledged 3D printing technology, backing it up with huge monetary investments. Although research on 3D printing started about 30 or so years ago, it is only in recent years that the project reached a high technical readiness level. As you can guess, many for-profit companies have opened shops to market 3D printers and provide the associated services.
To be sure, and as reported by The Wall Street Journal on 6 August 2015, some of these 3D Printer companies are facing a hard time, as consumers appear to be waiting for new models of 3D printers, perhaps with faster speeds of printing. Challenges notwithstanding, 3D printing seems have come to stay – no going back!
What is 3D printing anyway? A few-sentence crash-course in manufacturing (mechanical engineering) is in order. Here, we are talking of the processes involved in producing a physical object. For example, to manufacture plastic bottles, like coca cola bottles, you completely fill molds having the shape of the bottles with hot, molten (liquid) plastic and cool to solidify the melt into the shape of the bottles, followed by the removal of the molds. Injection molding, which is the manufacturing process of injecting molten plastic into molds, is the way that numerous plastic materials are fabricated. If you have liquid metals instead of plastic, you have a process called casting. This way, you don’t need to join pieces together. Complicated metallic parts, such as automobile engine blocks, are fabricated this way. Another manufacturing process – forming, is one in which the metallic raw material is shaped by stretching, bending, or compressing it by the application of large forces.
In the manufacturing process of machining, a sharp metal tool is used to remove unwanted materials by cutting them. Examples of this include drilling, sawing, milling, and turning. Machining tools include drill press – used to bore holes into metals, band saw – which is a sharp metallic blade used to make rough cuts through a metal, lathes, and milling machines. We also have the joining processes – welding, soldering, riveting, bolting, or the use of adhesives to bond components together. For example, many bicycle frames are welded together from individual pieces of metal tubing.
3D printing, despite its name, is actually a manufacturing process, like  the ones listed above, although the operation is conceptually the same as that involved in using an HP printer to print your Microsoft Word document on a piece of paper. There is a huge world of difference in the output though. Using an HP printer to print your document basically involves painting, in ink, characters or lines (fringes) on a printing medium (paper), and using the stipulated ink color for each character. (Color-fill is obtained by merely drawing several lines close to each other, to give the illusion of flooding.) In 3D printing, the outcome is not a character or a line on paper, or a patch of red spot, but a physical 3D object, like an iPhone case, that you can actually hold in your hand!
The invention of computer-aided design (CAD) and computer-aided manufacturing (CAM) about 30 or so years ago has enabled mechanical engineers to revolutionize the way mechanical parts are manufactured. In CAD, you must have a replica of the object that you want to manufacture. Specifically, you need to know the geometry of the object, which you represent by the coordinates of points on the object. A full geometric representation of the object must be obtained using some kind of graphics. The data with instructions on how to build the object is entered into the computer. Specialized software exists for this application. For more than twenty years now, we have had the technology to send the data in the CAD file to a machine that can read and translate the data and produce exactly the solid object described in the data file. The technique is what we call CAM.
3D printing uses the technique of additive manufacturing to make three-dimensional solid objects from a digital file. That is, the creation of a 3D printed object is achieved by laying down successive layers of material until the entire object is created. This is essentially what all 3D printers have in common: the manner in which production is carried out – layer by layer in an additive process – which contrasts from the traditional methods of production, which involve subtractive methods or molding/casting processes.
You can create a 3D digital file of an object yourself, using suitable CAD software, or download one from the web. Moreover, you don’t have to buy the printer – you can send your file to a third-party entity to print for you. There are 3D printers for plastic and metal objects.
This article continues next week.