The Technology of Fabbing

Many people are amazed when they first hear about 3D printing. They often believe it’s like the fictional Star Trek replicator, which was able to reproduce virtually any object, including food, within a few seconds. Miraculous, but we’re not quite there - yet. 

Unlike Star Trek, real 3D printing is much more understandable and actually quite similar to technologies people already understand, such as inkjet printing. The key concept is that 3D printing is “Additive”, meaning the object is constructed by gradually adding more material until the desired shape is achieved. Typically material is added in vertically stacked layers, one by one, from bottom to top. However, recent machines do this in hours, not seconds.

But that’s where it gets a little bit complicated. It turns out there are many different ways to perform “additive manufacturing”. It all depends on the form of the print media. Yes, there’s media, just like 2D printers have ink. 

Some printers use powdered media, which could be as complex as an exotic proprietary plastic or just plain table sugar. Usually the powder is spread thinly over the floor of the “build chamber” and then a mechanical arm moves over the powder to fuse/glue/melt specific portions of the powder into the shape of that layer. More powder is spread over top and the sequence repeats until the final top layer is constructed. The object must then be extracted from a tub full of unfused powder and cleaned up. 

Other printers use a more direct approach, similar to inkjet printers. A print head moves about the build chamber, depositing the media on specific areas. The build chamber’s floor then lowers a very small distance and the process repeats for the second and subsequent layers until the final top layer is produced. The completed object is then removed from the build chamber. 

A third common approach is to use sheet media, such as plastic sheets or even common paper. Sheets are inserted into the build chamber one at a time, where they are cut and fused to the layer below. This eventually builds up into the final object. Paper printers are among the least expensive to operate due to their widely available print media. 

Another approach often seen is Laser Sintering, which is not 3D printing per se, but operates in a similar manner and achieves similar results. A laser traces a pattern on the surface of a large tub of resin. The laser’s touch fuses a thin layer of resin into solid material. The floor of the tub lowers a small distance and a second layer is laser fused. Again, the object is built from bottom to top and when finished it is dramatically raised up from the liquid resin and appears to be created rather suddenly. 

Once built, objects may have to be polished or painted. They might be the final item, or perhaps they are simply used to create a mold for traditional manufacturing. Items could be fragile or robust depending on the type of print media employed. They might be part of a larger object that requires assembly because it was larger than the size of the build chamber. 

All of these factors exist today, but they are gradually improving in capability as each month passes. Even better, pricing for printers and print media continue to fall. Eventually we’ll see them appearing in homes across the land and then the world will begin to change.