Stanford University

Additive Manufacturing

Additive manufacturing, often referred to as 3D printing, is a process used to generate a physical model from a digital computer model. Generally, a model is "sliced" into thin layers by the printer software, and each layer is successively built up. Several different 3D printing technologies exist, with many different material options available. Each machine and material has unique properties that should be considered when choosing a process.

3D printers require an STL file, which can be generated using one of many different software programs. Solid models (instead of surface models) are generally used to generate appropriate STL files.

The PRL has seven 3D printers available for student use, all located in Room 36 in the Huang Engineering Center. 3D printing in the PRL has been used to build mechanical prototypes for testing, tooling for silicone molding and sand casting, and as artistic or decorative pieces. Students are required to pay for material costs before builds begin.

Machine Specifications

Manufacturer Stratasys FDM Ultimaker Formlabs
Machines F370 Ultimaker s5
Ultimaker 3
Ultimaker 2+
Form2 (x3)
Form3 (x3)
Additive manufacturing technology FDM (Fused Deposition Modeling) FFF (Fused Filament Fabrication) SLA (Stereolithography)
LFS (Low Force Stereolithography)
Process Description Plastic filament and support materials are pushed through heated extrusion tips that trace each cross-sectional layer.
Build time is approximately linear with the increase in cross-sectional area.
Functionally equivalent to FDM Liquid photopolymer resins are cured by laser as the part is pulled out of the resin bath
Software GrabCAD Print Cura PreForm
Layer Resolution 0.005"
0.06mm - 0.25mm 25um
Build volume (xyz) 14" x 10" x 14" 13" x 9.4" x 11.8"
8.7" x 8.7" x 8"
5.7” × 5.7” × 6.9”
Material ABS, ASA, PC-ABS, PLA, TPU92A with QSR soluble support material Ultimaker filaments are stocked, except for ABS Most Formlabs resins are stocked
Operation in the PRL Reservable on Webshop
requires completion of self-guided tutorial on the machine
Reservable on Webshop
requires completion of self-guided tutorial on the machine
Reservable on Webshop
requires completion of self-guided tutorial on the machine
Best option for: -Structural parts with wall thicknesses over approximately 0.080”

-Bulky parts that can benefit from decreased build cost using a sparsely-filled model
-Quick prototypes where surface imperfections are acceptable

-Bulky parts that can benefit from decreased build cost using a sparsely-filled model
-Small, precise parts with intricate features

-Parts that require specific material properties

Instructions for Use

To use the Stratasys, Ultimaker, or Formlabs machines, you need to prepare a 3D model. A reservation on WebShop is helpful to ensure that the machine will be available when you are ready. Take a look at the tutorial documents for Stratasys or Ultimaker before coming into Room 36 when using any of the machines for the first time.

Tech Notes

The three types of machines each have their own capabilities and limitations, along with different options and slicing softwares. Come by Room 36 to look some parts created with each of the three machines and get a better feel for their capabilities:

To create single-print assemblies on the Ultimaker or Stratasys machines, leave a gap of at least 0.020” between adjacent components. For example, a pin of diameter 0.125" should be centered in a hole of 0.165" diameter to ensure that the filament does not overlap on either side between the components. If your fit is very critical, we always suggest printing a test part to verify your geometry.

3D Hubs and Fictiv have excellent resources for designing and finishing printed parts - for example:

Alternative Additive Manufacturing Resources

The Product Realization Lab is a teaching laboratory and we find the research demand for us to print parts decreases our ability to fulfill our primary teaching mission. There is an alternative service organization on campus whose purpose is to fill this need, and there are numerous local and web-based services that can be used as well.

Additional Additive Manufacturing Resources:

If your additive manufacturing needs exceed the bandwidth of the Product Realization Lab, here are a few alternatives you might look into. Please remember that it is your responsibility to determine if a vendor, material, build process, and lead time are appropriate and will meet your needs.

On campus:

  • Garner Lab in Comparative Medicine. Connect through iLab. One of the big benefits to using this service is that they are part of the university system and payment for builds can be made directly with a PTA account.


Web-based: There are many web-based services that provide additive manufacturing services, using many different processes and materials.