Remember that piracy joke about downloading a pizza? Well, we are on the verge of that idea becoming a reality with 3D printing. Right now, 3D printing is still in its infancy, but product designers and engineers are excited about the possibilities that are becoming available as we continue to develop various practical applications for this technology. Learning how does 3D printing work can seem complex, but we’re here to guide you through it. 

It’s definitely not just pizza (or food) that a 3D printer is possible of printing. Ceramic bowls, plastic toys, metal gears, stoneware pottery, and even human body parts for transplants (in the future). The possibilities for 3D printing objects using the materials that comprise them are practically endless. 

So, how does 3D printing work? Before we can answer that question, we need to look at the machine itself, the 3D printer.

What Is a 3D Printer?

A 3D printer prints out 3D objects, much like a regular printer prints 2D pictures of objects, except that it’s not entirely 2D. A regular printer doesn’t stain a paper with ink; it physically adds a very thin layer of ink to the surface of the page (you can see it through a microscope). Now, imagine if you were to run that page through the printer a hundred or a thousand times. Theoretically, you would eventually build up the layers of ink until you have a copy that has 3D letters. That’s the basis of 3D printing technology; these thin layers of printed technology fuse together into a fully solid 3D object that functions as if it was created normally through a different process.  

The process of 3D printing is much more complicated than regular printing, can take a long time, and has a high chance of errors occurring during printing. However, these problems are fixable with time and will lessen as the technology becomes more advanced as we learn more about it.

Why Is 3D Printing a GameChanger?

There are many opportunities that become available through 3D printing.

The printed pizza I mentioned has already started being developed by NASA with the company BeeHex for astronauts since freeze-dried food is less than appealing and missions to space are getting longer with every new planet we discover. According to Futurism, the technology will soon be used for us here on Earth as well and has raised a million dollars in funding. The 3D printing pizza machine branded as ‘Chef 3D’ may be in theme parks, malls, and sports arenas soon.

But as we said, it’s not just food that makes 3D printing so revolutionary. 3D printing allows for made-to-order items that are measured to fit you and your needs. Today, buying a made-to-order item is possible, but it is also very expensive because of the labor-intensive hours of work it takes to make something unique and specific to an individual. 3D printing makes it affordable because rather than a person having to create the item by hand, a machine does it with only a few instructions from the creator.

Speaking of made-to-order items, we mentioned that 3D printing technology could potentially print functional organs for transplants and could print prosthetics that are made to fit a specific individual.

This is not to say 3D printing doesn’t have it’s limitations, particularly right now because we’ve yet to fully understand the capabilities this technology has. The cost of producing one 3D printed item is still higher than mass-produced items on an assembly line even though the cost of a 3D printer is way less than opening a production factory, but that will change given enough time and knowledge.

How Does 3D Printing Work?

Originally, the term 3D printing referred to a specific process in which a binding agent is deposited onto a powder bed with inkjet printer heads layer by layer. However, it has now become used in common vernacular as an umbrella term for any process additive manufacturing technique. In the industry, the preferred term to describe the various processes of printing technology is additive manufacturing because all the materials are being added. It is a retronym for subtractive manufacturing which has the opposite theme.  

In learning how 3D printing works, the first step is to have it communicating with a computer (much like a regular printer today). There are three main stages a 3D print must go through as it prints.

Modeling 

There are a few ways to create a model for a printable 3D object. The first is a computer-aided design (CAD) package, which is preferred because the models created with CAD result in reduced errors that can be corrected before printing. This allows for verification of the design before it’s actually printed. Creating a 3D scan is also an option via a 3D scanner, which collects digital data on the shape and appearance of an object in real life and then creates a digital model. The third option is to photograph an object with a digital camera and using photogrammetry.

Printing

Before we can print, we have to run the file for the model to look for any errors. An STL (STereoLithography file format) from a CAD will usually produce these types of errors in output:

  • Holes
  • Faces normals
  • Self-intersections
  • Noise shells
  • Manifold errors

The errors must be “fixed” in the model’s STL before printing begins. An STL created by 3D will produce more errors than a CAD model. When that’s completed, the error-free STL model must run through a program called “Slicer,” which will divide the model into several tiny layers to prepare it for printing and produces a g-code. The g-code is run through 3D printing client software that gives instructions to the specific 3D printer called an FDM printer that prints FFF (Fused Filament Fabrication). Construction of the model through today’s 3D printing standards can take hours or sometimes days depending on the size and complexity of the model and the method of printing used.

When printing, the printer has a printer resolution that describes the layer thickness and X-Y resolution in dots per inch (dpi) or micrometers (µm). Typically the layer thickness is around 250 µm (100 dpi), but some machines can produce layers as thin as 16 µm (1,600 dpi). The X-Y resolution, which describes the quality of the print, usually has particles (3D dots) that are 50 to 100 μm (510 to 250 DPI). With that printer resolution, the mesh resolution should be around 0.01-0.03 mm and a chord length ≤ 0.016 should generate an optimal STL output file for the model. When you specify a higher resolution, you can create larger files without an increase in print quality.

Techniques such as injection molding can be less expensive when producing polymers in a large quantity, but additive manufacturing is usually faster, more flexible, and less expensive in smaller quantities. With 3D printers, concept models and small parts can be created by development teams and designers the ability to print from a desktop 3D printer. Paradoxically, printing a complex item can be cheaper than printing a simple one. The reason for that is that a complex item can be broken down into individual parts and fused together after printing while a simple item is one object that could take much longer to print and therefore has a higher risk of error during the print.

Finishing

Even though the standard printer-produced resolution is usually fine, it can sometimes be better to create an oversize object with standard resolution and then remove material through a higher quality subtractive process, which can lead to greater precision.

The layers created using additive manufacturing leads to a strain-stepping effect on surfaces that are curved or tilted in the object. Some printable polymers such as ABS (Acrylonitrile Butadiene Styrene) allow for the finish to be smoothed using chemical vapor processes based on acetone or a similar solvent.

In some cases, additive manufacturing techniques are able to use multiple materials while constructing parts. They are able to print in multiple colors and color combinations simultaneously meaning they may not need to be painted.

There are printing techniques that require internal structural supports for overhanging features during construction that should be dissolved or removed after completion.

Commercialized metal 3D printers cut the metal component off the metal substrate after deposition. There is a new process for GMAW (Gas Metal Arc Welding) 3D printing allowing for substrate surface modifications for removing aluminum or steel.

Conclusion

We are still a few decades away from being able to download and print a pizza in our own homes, but the knowledge we could one day is a prospect we have to admit is exciting, even though it might still raise a few eyebrows. People were skeptical about home computers and mobile phones before they became a reality too… and now everyone and their mother uses them every day for business and pleasure. 

So, the world may not be completely ready for 3D printing yet, but it’ll be here soon, and it’ll be here to stay.