Emulating Mass Properties With 3D Printing

When 3D printing products it is common for the fabricated component to have significantly different mass properties to the as-designed product. This is especially true in early-stage design prototype fabrication, where understanding the geometric form of a prototype leads to rapid production of the artefact. There are several reasons for this, but the main three are:

  1. Neglecting to include internal components when generating a geometric representation of the external shell,
  2. Using a lower density thermoplastic rather than the designed-for material, and,
  3. Using a low-density infill pattern to save on material/production costs and time.

For some applications, this may not be important, however, it is common for stakeholders to interact with early-stage products to understand feel. Inevitably, the mass properties an artefact exhibits changes the perceived feel – with the force and torque required for interaction being directly linked to the product’s mass properties. As such, it is hypothesised that a method through which mass properties can be emulated in 3D printed products would be desirable.

This work demonstrates a methodology (presented below) through which product mass properties can be emulated using a standard 3D printing process (FDM/MEX/FFF) and machine. Written in Python, the code is able to produce a cellwise breakdown highlighting where mass needs to be placed to best emulate the desired mass properties. Work is currently continuing to slice a set of example products ready for 3D printing.

Proposed mass property emulation methodology (with tools used)

Initial results have been promising, with several case studies considered. The results from two of these – a Nintendo Switch JoyCon and Bosch electric hand drill – are shown below. The mass error was less than 1g for each of these parts, and the centre of mass position error less than 1 mm (averaged).

Graphical representation of results, showing the localisation of mass to emulate the product's intended mass properties.

This work is currently being written up for a journal paper. Check back soon for updates on publication and further developments.


Harry Felton

Harry Felton

Research Engineer

Jason Yon


Ben Hicks

Professor, Director

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