If you are a fresh industrial design student, you'll most likely have your first try at 3D printing this semester or this year. And while a lot of focus has been on the printers themselves, it's equally important and fascinating to look at the materials we can use.

There are surprisingly few limitations placed on the kinds of materials used to print 3D objects. As additive manufacturing develops into a widespread practice it's important to focus on the potential of the ingredients used. Here's a rundown of the popular and the strange.

The most commonly used materials today are the thermoplastics (polymers.) Typically the polymers are in the form of filament made from resins.

- Acrylonitile butadiene styrene (ABS) also known as lego plastic, is perhaps one of the most commonly used plastics in 3D printing.
- Polylactic acid (PLA) has the flexibility to be hard or soft and is starting to gain popularity. There is also a soft form of PLA that is rubbery and flexible.
- Polyvinyl alcohol (PVA) is a dissolvable material that is used as a support, that then gets washed away once the object is created.
- Polycarbonate requires high-temperature nozzle design and is in the proof-of-concept stage.

Plastics can be mixed with carbon fiber to make them stronger without adding weight.

There are also several metals that can be used for additive manufacturing:

- Steel
- Stainless steel
- Titanium
- Gold
- Silver

Several types of processes work with metals and metal alloys. These are direct metal laser sintering (DMLS), electron-beam melting, selective laser melting (SLM). SLM can worth with plastics, ceramics abut also metal powders, and can produce metal objects that have strikingly similar properties as those of traditionally manufactured metals. (We previously posted videos of each of the methods listed above.)Photopolymers—materials that can harden in the presence of light—are used in stereolithography (SLA) and digital light processing (DLP). SLA is often used to make prototypes or models.

But there are more innovative and unusual materials for printing—and these give insight into how far-reaching the technology will go.

Bio-ink: This is made from stem cells which can be layered just like most 3D printed materials, and together the layers literally form tissue. So far blood vessels, bladders and kidney parts have been 3D printed.

Full-color sandstone: This material allows for 3D printed object in pretty much any color. Currently it's used for small toys and architecture. (See the tiny man above made from sandstone in the Shapeways factory.)

Glass: Glass can be ground into a powder, and then layered, bonded with adhesive spray and baked.

Medications: Currently engineers and chemists are working to print pharmaceuticals. The security and structures around this practice ought to be closely watched in the next decade.

Bone: A bone-like material (made of silicon, calcium phosphate and zinc) has been printed and then integrated with growing human bone cells. Within a week new bone grew on the structure, and later the printed material dissolved, leaving the new human bone growth.

Chocolate: This makes sense. And with the success of this material you can imagine what 3D printing might now do to baking and cooking. Apparently chocolate printers use the computer-aided-manufacturing systems in 3D printers to set up the designs and then print...your chocolate fix is just a click away. (See above photo.)

Objet Digital Material: Objet is a brand owned by Stratasys—a big maker of 3D printing systems—and is considered to be forefront of innovation in 3D printing materials. Their multi-jet printers that can print multiple materials at the same time. This allows for production of objects that have different textures, colors and properties.