What is 3D Printing
What can you print?
Material Science
Preparing to print
The Design Process
Modeling Basics
Additional Resources

What is 3D Printing

This lesson introduces you to 3D Printing, specifically the history of 3D printing, the different types of machines, the materials you can use, and the current and future applications of the technology. Since the 1980's 3D Printing has been a disruptive technology, and 3D printers have been changing the way we create and learn. Desktop 3D printers are affordable, personal fabrication tools, that allow anyone at any skill level to become producers, inventors and artists. The process of designing, inventing and fabricating exposes those new to 3D printing to various industries such as industrial design, engineering and material science.

A very brief history

1983: Chuck Hull invents stereolithography
SLA works by curing and solidify successive layers of liquid photopolymer resin using an ultraviolet laser.

1986: Carl Deckard and Joe Beaman develop Selective Laser Sintering
Selective Laser Sintering is similar to SLA, but instead of liquid resin, powdered materials including nylon, ceramics, glass, aluminum, to steel or silver can be used.

1986: 3D Systems is founded
Chuck Hull founds 3D systems, which develops its first commercial 3D printer, the Stereolithography Apparatus (or SLA-1)

1988: Scott Crump invents Fused Deposition Modeling
Fused Deposition Modeling heats and extrudes thermoplastic filament, depositing layers of semi-liquid beads along an STL-defined extrusion path.

1989: Scott Crump founds Stratasys

1990: DTM creates the first Selective Laser Sintering machine
Four Selective Laser Sintering machines were built, but none were ever sold. Each cost $300,000-$400,000.

1991: Helisys commercializes Laminated Object Manufacturing (LOM)
LOM bonds and cuts sheet material using a digitally guided laser.

1993: MIT licenses 3DP technology to several companies including Z Corp
MIT's Three Dimensional Printing (3DP) spreads a thin layer of powdered material on a flat bed, solidifying successive layers with fine jets of binding agent. MIT licenses it technology to several companies including ZCorp.

1999: Anthony Atala leads team that successfully implants a lab-grown bladder into a human patient.
Anthony Atala, director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine, leads a research team that successfully implants a lab-grown bladder into a human patient. The organ is built by seeding a 3D-printed scaffold with bladder cells.

2005: Dr. Adrian Bowyer founds RepRap, an open-source project to create a Fused Filament Fabrication (FFF)
The aim of the RepRap (Replicating Rapid Prototyper) project is is to create a Fused Filament Fabrication (FFF) 3D printer that can print most of its own components. FFF instead of FDM is chosen to describe the process in order to avoid legal issues with Stratasys.

2008: Makerbot launches Thingiverse, a repository of designs for the 3D design community
Thingiverse was started in November 2008 by Zach "Hoeken" Smith as a companion site to MakerBot Industries, a DIY 3D printer kit making company.

2011: Researchers at Cornell University began to build 3D food printer
The project comes out of Cornell's Fab@Home venture, headed up by associate professor Hod Lipson. Started in 2005, the project aims to create do-it-yourself versions of machines that can manufacture custom objects on-demand. The group started experimenting with food fabrication in 2007.

Types of 3D Printers

  • Stereolithography (SLA)

    A process that works by curing and solidifying successive layers of liquid photopolymer resin using an ultraviolet laser.

    Examples of Desktop 3D Printers are:
    SLA models can:
    • be translucent
    • have a high resolution
    • have undercuts
    • be large
    • have high level of accuracy and details

    The cons
    • The resin is expensive.
    • Process only works with photopolymers which are not stable over time.
    • Leftover resin can't be reused.
    • Resin may cause skin, eyes and respiratory system irritation, and skin sensitization/allergic reaction by skin contact. Inhalation of high vapor concentration may cause headaches and nausea.
    • Resin cannot be disposed of in drains, sewers, water supplies, or soil. Dispose of in accordance with all applicable federal, state and local regulations.
    • Printer must be used in well-ventilated area.
    • You must wear impervious gloves (nitrile or neoprene) for routine handling. Aprons, long pants, and long sleeved shirts are also recommended.
    • Chemical splash goggles or a face shield is recommended during operations where splashing could occur.
  • Digital Light Processing (DLP)

    This process is similar to stereolithography in that it works with photopolymers. DLP uses a more conventional light source than SLA, such as an arc lamp, with a liquid crystal display panel or a deformable mirror device (DMD).

    DLP produces highly accurate parts with high resolution, but its similarities also include the same requirements for support structures and post-curing. One advantage of DLP over SLA is that only a shallow vat of resin is required to facilitate the process, which generally results in less waste and lower running costs.

    Desktop example
  • Fused Deposition Modeling (FDM)

    This process uses certain melted thermoplastic materials that are joined together to form a shape. As the material hardens, a 3D object is formed.

    Desktop printers of this sort use Fused Filament Fabrication (FFF) technology. Examples of these 3D printers are:
  • Selective Laser Sintering (SLS)

    Similar to SLA, but instead of using liquid resin, powdered material is used. The material can be anything from nylon, ceramics, glass, aluminum, to steel or silver. The laser is traced across a bed of tightly compacted powdered material, according to the 3D data fed to the machine, in the X-Y axes. As the laser interacts with the surface of the powdered material it sinters, or fuses, the particles to each other forming a solid.

    The build chamber is completely sealed as it is necessary to maintain a precise temperature during the process specific to the melting point of the powdered material of choice.

    Key advantages
    • Powder bed serves as support structure allowing for overhangs and undercuts.
    • Parts made through this process are strong.

    Key disadvantages
    • Requires high temperatures.
    • Requires long cooling times.
    • Porosity is an issue with this process, and some applications necessitate infiltration with another material.
    • There can be surface inaccuracies.
  • Selective Laser Melting (SLM)

    Similar to SLS. However, instead of simply combining the powder granules together, the powder is melted.
  • Electronic Beam Melting (EBM)

    In this process electronic beams are used instead of UV rays.
  • Laminated Object Manufacturing (LOM)

    In this process, to manufacture an object, plastic, paper and metal are glued together. After that, they are cut with a knife or a laser to give them a shape.
  • Selective Deposition Lamination (SDL)

    This process builds parts layer by layer using standard copier paper. Each new layer is fixed to the previous layer using an adhesive. A higher density of adhesive is deposited in the area that will become the part, and a lower density of adhesive is applied in the surrounding area that will serve as the support.

    After a new sheet of paper is fed into the 3D printer, the build plate is moved up to a heat plate and pressure is applied. Pressure ensures the bonding between the two sheets of paper. The build plate then lowers and an adjustable Tungsten carbide blade cuts one sheet of paper at a time, creating the edges of the part. When cutting is complete, the 3D printer deposits the next layer of adhesive and so on until completion.

Why 3D print

3D Printing:
  • allows for data visualization.
  • provides tactile feedback.
  • facilitates prototyping.
  • invites one into the realm of the D.I.Y. ethic.
  • engages one in STEM based projects.
  • is another means of communication.
3D Printing incorporates:
  • Additive Manufacturing.
  • Computer Aided Design and Drafting (CADD).
  • Rapid Prototyping (RP).
  • Reverse Engineering.
  • Brainstorming and ideation.
  • Workflows.