Spring 2018 3DoT Hexy: Decision on Picking Materials and Fabrication Method

By: Raymundo Lopez-Santiago (Mission, System, and Test)

Verified by: Eduardo De La Cruz (Project Manager and Manufacturing Engineer)

Approved by: Miguel Garcia (Quality Assurance)


The purpose of this post is to determine what material and method of fabrication we will end up going with for the fabrication of our prototype and our final model.

Related Requirements

Level 1 Requirements

  • For quick production of the prototype, the preliminary project shall be restricted to six hours of total printing time with a 2 hours limit for each single print.
  • The robot shall incorporate 3D printed parts to demonstrate the feasibility of the 3DoT board for 3D printed robots.
  • The spiderbot shall have an allocated budget of $250, however to compete with the existing robot toy market we shall try to minimize the cost of production as much as possible.  

Level 2 Requirements

  • The robot shall use 3D printed chassis and legs. This follows from the project level requirement about using 3D printed parts.

Update May 06, 2018

This task has been well defined in the past by multiple groups, for the most part, the same type of fabrication methods tend to be picked, as well as the same type of materials for production of small robot toys. The pattern is:

For complex parts: 3D printing


  • cost and time of fabrication.

Materials most often used:

  • ABS (acrylonitrile-butadiene styrene) due to cost and weight of material.
  • PLA (polylactic acid) due to higher quality. Used only on final model

For final prints:

  • Highest quality ABS and Acetone smoothing, click here for instructions on how to do it.

For flat parts: Laser Cutting


  • easy access to a FSL MUSE laser cutter in Prof. Hill’s office.
  • Cost (you just have to worry about the cost of the material).

Materials most often used:

  • Baltic birch plywood due to cost and weight of the material.
  • Acrylic due to higher quality of material.

If interested in reading trade studies on these materials, and other materials tested, reference the resource material provided below.



For the most part, we have already established in our mission requirement list that we will be using 3D printed parts to make our robot. We will most likely follow this requirement due to the fact that most of our 3D printed parts will be to complex for laser cutting. However, we will remain open to the possibility of laser cutting. If we do end up laser cutting parts for our project, we will use birch wood because of the cost and weight of the material, in comparison to other materials such as aluminum or acrylic.


  1. https://www.arxterra.com/spring-2017-spiderbot-2/
  2. https://www.arxterra.com/spring-2016-3dot-david-alternative-printing-for-small-parts/
  3. https://www.arxterra.com/material-trade-off-study/