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Making design for metal powder bed fusion accessible with the GAPS worksheet

Written by Jennifer Bracken

Published on August 14, 2020

Making an accurate prediction if your component is suitable for AM at the beginning of the design phase can save you time, money, and material. To help with that researchers at Penn State University created an easy to use worksheet to help designers and engineers make better design decisions from the beginning.

Design for Additive Manufacturing (DfAM) is currently synonymous with expert knowledge and external consultants for many companies. Particularly for higher cost technologies, such as metal powder bed fusion, component design requires extensive additive manufacturing (AM) knowledge to obtain successful printed components without many expensive test builds. If a part is incorrectly designed, it can cause thousands of dollars of lost time and material through a failed print. To avoid this situation, specialists must be consulted throughout the AM process; however, the shortage of trained personnel familiar with AM can create a bottleneck during design. This scarcity of expertise can make AM projects take longer, be more expensive due to trial-and-error, or even become unattainable without frequent access to an expert.

In order to help people and businesses identify candidate parts for printing with Powder Bed Fusion (PBF) AM and design new parts to be made with PBF AM, a DfAM tool called the GAPS (Geometry for Additive Part Selection) worksheet has been developed. It is designed for use by those with little prior knowledge of PBF. This worksheet allows the user to score a design for PBF suitability, and to compare suitability of a collection of designs for printing with PBF. It also enables users to see geometric aspects of designs that often affect printability, thus giving them the opportunity to modify those aspects in designs they are evaluating. The worksheet contains nine commonly applicable geometric features known to affect PBF AM printability and uses publicly available data to support the values used for design guidance. The values for all criteria are totaled to predict the suitability of PBF AM.

Figure 1: Image of GAPS worksheet courtesy of Jennifer Bracken and Timothy W. Simpson.

This worksheet is presented during a webinar as part of the Design for Additive Manufacturing for Metal Series. Use of the worksheet to rate components is explained step-by-step, as is use of the worksheet to filter large sets of parts for the best AM candidates. With this worksheet, designers will be able to quickly overcome common early design mistakes and more easily generate and identify new designs to be additively manufactured via PBF.

The GAPS worksheet was first published as part of the journal paper “Design for Metal Powder Bed Fusion: The Geometry for Additive Part Selection (GAPS) Worksheet” in Additive Manufacturing, Volume 35, October 2020, by Jennifer Bracken, Thomas Pomorski, Clinton Armstrong, Rohan Prabhu, Timothy W. Simpson, Kathryn W. Jablokow, William Cleary, and Nicholas A. Meisel. The paper can be found here:

Jennifer Bracken

Jennifer Bracken is a researcher passionate about design – specifically, design for manufacturing and engineering design. She currently focuses on development of additive manufacturing tools and design for additive manufacturing workshops. At this time, she is a mechanical engineering PhD candidate at Penn State University. In the past she has worked in engineering design and design for manufacturing for Westinghouse, Arconic, Epiphany Solar Water Solutions, Alcoa, and the University of Pittsburgh’s Swanson Center for Product Innovation.