Session: 02-01-03: 7th Annual Conference-Wide Symposium on Additive Manufacturing: Polymers I

Paper Number: 95317

95317 - An Experimental Investigation of the Mechanical Behavior of 3D Printed Structures As a Function of Manufacturing Process Decisions 

Additive manufacturing (AM) processes, such as material extrusion and vat polymerization, build parts out of a base material in a layer-by-layer fashion. There are numerous AM processes currently in use by the AM community today, and each of these processes works with different build materials and uses unique bonding or deposition technologies to realize solid 3D objects.  Furthermore, all AM machines, regardless of build material chosen, will also require a designer to make numerous choices concerning part orientation and machine process parameters in order to successfully fabricate an object.  Part orientation describes how an object is positioned in the build volume of an AM machine, and process parameters describe the factors that a user can select such as layer height. These choices can obviously affect the quality of the objects produced, as has been the focus of many research efforts to date, but can also drive the mechanical behavior of those objects when they are used in functional applications. The mechanical behavior of parts produced via AM is becoming increasingly important as AM systems become more widely used, and as AM materials with better engineering performance become more widely available. As a result, there is a very real need to have datasets and design tools capable of accurately predicting how parts fabricated via AM systems will behave mechanically. Numerous studies have looked at quantifying how strong 3D printed structures are based on the process parameters used to deposit the build material, including parameters such as polymer temperature, layer height and infill percentage for example. Necessarily the majority of these studies have focused on a single AM system or a single build material, meaning the results produce by those studies are often interesting, but may not be helpful in drawing general design for AM conclusions that are widely applicable. Additionally, many of the studies recently reported in the literature focused on this important problem have not considered the effects of part orientation on the mechanical behavior of AM parts. Part orientation is a critical aspect of for how an AM part will perform mechanically because different orientations (or build angles) may result in significantly different levels of adhesion between the bonded layers of the resulting part, and this is a factor shared by practically all AM systems. This paper presents the results of an experimental study specifically designed to explore this important factor and its effect on several key mechanical properties including bending stiffness, yield, fracture toughness and ultimate strength. This study consisted of printing and testing a large set of parts (or simple beams in this case) using a wide variety of build angle geometries, in addition to also considering factors focused on by previous studies.  This study considered parts produced on multiple printers, two different AM technologies (material extrusion and vat polymerization), and various printing materials in order to generate a dataset that can be used in the modeling and design of functional parts to be manufactured via various AM systems.  The results produced are compared to the data reported from a previously conducted similar study that did not consider build orientation, and the effects of build orientation seen in the data clearly show the need for designers to consider this important parameter carefully when designing parts for AM applications.

 

Presenting Author: Josh Hamel Seattle University

Presenting Author Biography: Dr. Hamel is a dedicated educator and researcher with a varied background in multiple engineering disciplines. Dr. Hamel is keenly interested in the engineering design process and his current research efforts are focused on multidisciplinary design optimization (MDO) and the integration of design optimization and additive manufacturing. He has taught courses in engineering design, mechanics, engineering computation, thermodynamics, fluid mechanics, experimental data analysis and flight stability. Dr. Hamel also serves as a reviewer for various ASME publications and conferences.

Authors:

Josh Hamel Seattle University
Logan Kamla Seattle University