Investigating the Role of Geometric Dimensioning and Tolerancing in Additive Manufacturing

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Gaurav Ameta ◽  
Robert Lipman ◽  
Shawn Moylan ◽  
Paul Witherell
Keyword(s):  
Additive Manufacturing ◽  
Tolerance Analysis ◽  
Geometric Accuracy ◽  
Geometric Dimensioning And Tolerancing ◽  
Dimensioning And Tolerancing ◽  
Internal Cavities ◽  
Functional Features ◽  
Traditional Manufacturing ◽  
Am Processes

Additive manufacturing (AM) has increasingly gained attention in the last decade as a versatile manufacturing process for customized products. AM processes can create complex, freeform shapes while also introducing features, such as internal cavities and lattices. These complex geometries are either not feasible or very costly with traditional manufacturing processes. The geometric freedoms associated with AM create new challenges in maintaining and communicating dimensional and geometric accuracy of parts produced. This paper reviews the implications of AM processes on current geometric dimensioning and tolerancing (GD&T) practices, including specification standards, such as ASME Y14.5 and ISO 1101, and discusses challenges and possible solutions that lie ahead. Various issues highlighted in this paper are classified as (a) AM-driven specification issues and (b) specification issues highlighted by the capabilities of AM processes. AM-driven specification issues may include build direction, layer thickness, support structure related specification, and scan/track direction. Specification issues highlighted by the capabilities of AM processes may include region-based tolerances for complex freeform surfaces, tolerancing internal functional features, and tolerancing lattice and infills. We introduce methods to address these potential specification issues. Finally, we summarize potential impacts to upstream and downstream tolerancing steps, including tolerance analysis, tolerance transfer, and tolerance evaluation.

Tolerance Specification and Related Issues for Additively Manufactured Products

2015 ◽  
Author(s):  
Gaurav Ameta ◽  
Paul Witherell ◽  
Shawn Moylan ◽  
Robert Lipman
Keyword(s):  
Free Form ◽  
Complex Geometries ◽  
Geometric Accuracy ◽  
Current State ◽  
Manufactured Products ◽  
Internal Cavities ◽  
Tolerance Specification ◽  
Functional Features ◽  
Traditional Manufacturing ◽  
Am Processes

Additive manufacturing (AM) has gained increased attention in the last decade as a versatile manufacturing process for customized products. AM processes can create complex free-form shapes, introducing features such as internal cavities and lattices. These complex geometries are either not feasible or very costly with traditional manufacturing processes. This creates new challenges in maintaining and communicating dimensional and geometric accuracy of parts produced. In order to manufacture a product that meets functional needs, the specification of those needs through geometry, material and tolerances is necessary. This paper surveys the current state and needs of geometry related accuracy specification mechanisms for AM, including a review of specification standards such as ASME Y14.5 and ISO 1101. Emerging AM-related tolerancing challenges are identified, and a potential plan of action is put forth for addressing those challenges. Various issues highlighted in this paper are classified as (a) AM-driven specification issues and (b) specification issues highlighted by the versatility of AM processes. AM-driven specification issues include build direction, layer thickness, support structure related specification, and scan/track direction. Specification issues highlighted by the versatility of AM processes include, region-based tolerances for complex freeform surfaces, tolerancing internal functional features, tolerancing lattice and infills. Basic methods of solving these specification issues are also highlighted.

scholarly journals Investigation of microstructure and hardness of a rib geometry produced by metal forming and wire-arc additive manufacturing

2018 ◽  
Vol 190 ◽  
pp. 02005 ◽  
Author(s):  
Markus Hirtler ◽  
Angelika Jedynak ◽  
Benjamin Sydow ◽  
Alexander Sviridov ◽  
Markus Bambach
Keyword(s):  
Additive Manufacturing ◽  
Metal Forming ◽  
Batch Size ◽  
Unit Costs ◽  
Batch Sizes ◽  
Traditional Manufacturing ◽  
Manufacturing Technologies ◽  
Forming Tools ◽  
Wire Arc Additive Manufacturing ◽  
Am Processes

Within the scope of consumer-oriented production, individuality and cost-effectiveness are two essential aspects, which can barely be met by traditional manufacturing technologies. Conventional metal forming techniques are suitable for large batch sizes. If variants or individualized components have to be formed, the unit costs rise due to the inevitable tooling costs. For such applications, additive manufacturing (AM) processes, which do not require tooling, are more suitable. Due to the low production rates and limited build space of AM machines, the manufacturing costs are highly dependent on part size and batch size. Hence, a combination of both manufacturing technologies i.e. conventional metal forming and additive manufacturing seems expedient for a number of applications. The current study develops a process chain combining forming and additive manufacturing. First, a semi-finished product is formed with forming tools of reduced complexity and then finished by additive manufacturing. This research investigates the addition of features using AlSi12 created by Wire Arc Additive Manufacturing (WAAM) on formed EN-AW 6082 preforms. By forming, the strength of the material was increased, while this effect was partly reduced by the heat input of the WAAM process.

Complex Solutions for Complex Problems? Exploring the Role of Design Task Choice on Learning, Design for Additive Manufacturing Use, and Creativity

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Rohan Prabhu ◽  
Scarlett R. Miller ◽  
Timothy W. Simpson ◽  
Nicholas A. Meisel
Keyword(s):  
Additive Manufacturing ◽  
Self Efficacy ◽  
Engineering Students ◽  
Educational Interventions ◽  
Problem Statement ◽  
Design Task ◽  
Complex Solutions ◽  
Future Work ◽  
Am Processes

Abstract The integration of additive manufacturing (AM) processes in many industries has led to the need for AM education and training, particularly on design for AM (DfAM). To meet this growing need, several academic institutions have implemented educational interventions, especially project- and problem-based, for AM education; however, limited research has explored how the choice of the problem statement influences the design outcomes of a task-based AM/DfAM intervention. This research explores this gap in the literature through an experimental study with 175 undergraduate engineering students. Specifically, the study compared the effects of restrictive and dual (restrictive and opportunistic) DfAM education, when introduced through design tasks that differed in the explicit use of design objectives and functional and manufacturing constraints in defining them. The effects of the intervention were measured through (1) changes in participant DfAM self-efficacy, (2) participants' self-reported emphasis on DfAM, and (3) the creativity of participants' design outcomes. The results show that the choice of the design task has a significant effect on the participants' self-efficacy with, and their self-reported emphasis on, certain DfAM concepts. The results also show that the design task containing explicit constraints and objectives results in participants generating ideas with greater uniqueness compared with the design task with fewer explicit constraints and objectives. These findings highlight the importance of the chosen problem statement on the outcomes of a DfAM educational intervention, and future work is also discussed.

Favoring Complexity: A Mixed Methods Exploration of Factors That Influence Concept Selection in Design for Additive Manufacturing

2020 ◽  
Author(s):  
Rohan Prabhu ◽  
Rainmar L. Leguarda ◽  
Scarlett R. Miller ◽  
Timothy W. Simpson ◽  
Nicholas A. Meisel
Keyword(s):  
Additive Manufacturing ◽  
Selection Process ◽  
Solution Space ◽  
Idea Generation ◽  
Concept Selection ◽  
Educational Groups ◽  
Early Design Stages ◽  
Traditional Manufacturing ◽  
Design For Am

Abstract The capabilities of additive manufacturing (AM) open up designers’ solution space and enable them to build designs previously impossible through traditional manufacturing. To leverage AM, designers must not only generate creative ideas, but also propagate these ideas without discarding them in the early design stages. This emphasis on selecting creative ideas is particularly important in design for AM (DfAM), as ideas perceived as infeasible through the traditional design for manufacturing lens could now be feasible with AM. Several studies have discussed the role of DfAM in encouraging creative idea generation; however, there is a need to understand concept selection in DfAM. In this paper, we investigated the effect of two variations in DfAM education: 1) restrictive DfAM and 2) dual DfAM (opportunistic and restrictive) on students’ concept selection process. Specifically, we compared the creativity of the concepts generated by the students to the creativity of the concepts selected by them. Further, we performed qualitative analyses to explore the rationale provided by the students in making these design decisions. From the results, we see that teams from both educational groups select ideas of greater usefulness; however, only teams from the restrictive DfAM group select ideas of higher uniqueness and overall creativity. Further, we see that introducing students to opportunistic DfAM increases their emphasis on the complexity of designs when evaluating and selecting them. These results highlight the need for DfAM education to encourage AM designers to not just generate but also select creative ideas.

A Review on Process Monitoring and Control in Metal-Based Additive Manufacturing

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Gustavo Tapia ◽  
Alaa Elwany
Keyword(s):  
Additive Manufacturing ◽  
Process Monitoring ◽  
Monitoring And Control ◽  
Part Quality ◽  
Industrial Sectors ◽  
Process Monitoring And Control ◽  
Traditional Manufacturing ◽  
Manufacturing Technologies ◽  
And Control ◽  
Am Processes

There is consensus among both the research and industrial communities, and even the general public, that additive manufacturing (AM) processes capable of processing metallic materials are a set of game changing technologies that offer unique capabilities with tremendous application potential that cannot be matched by traditional manufacturing technologies. Unfortunately, with all what AM has to offer, the quality and repeatability of metal parts still hamper significantly their widespread as viable manufacturing processes. This is particularly true in industrial sectors with stringent requirements on part quality such as the aerospace and healthcare sectors. One approach to overcome this challenge that has recently been receiving increasing attention is process monitoring and real-time process control to enhance part quality and repeatability. This has been addressed by numerous research efforts in the past decade and continues to be identified as a high priority research goal. In this review paper, we fill an important gap in the literature represented by the absence of one single source that comprehensively describes what has been achieved and provides insight on what still needs to be achieved in the field of process monitoring and control for metal-based AM processes.

scholarly journals Investigating the Gap between Research and Practice in Additive Manufacturing

2021 ◽  
Author(s):  
Jennifer Bracken ◽  
Zachary Bentley ◽  
James Meye ◽  
Erik Miller ◽  
Jablokow Kathryn W. ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Idea Generation ◽  
Concept Generation ◽  
Technical Problems ◽  
Before And After ◽  
Implementation Time ◽  
Design Objects ◽  
Traditional Manufacturing ◽  
Commercial Organization ◽  
Am Processes

Additive manufacturing (AM) provides opportunities to design objects differently than traditional manufacturing methods allow, but only if designers understand the possibilities AM presents. In this study, we examined whether an AM workshop combined with an idea generation session could inspire engineering professionals to use AM solutions to solve current technical problems they face. All subjects were employees at an organization that will be referred to as Company X, a multinational commercial organization based in North America. During the study, we collected ideas for 24 projects generated before and after a training workshop focused on design for AM. In the workshop, we provided three hours of instruction about design for two metal-based AM processes. The participants’ ideas were assessed using four specific metrics: (1) cost, (2) time,(3) completeness of solution, and (4) quality, which was a function of feasibility, usefulness, and novelty. Using these data, we explored whether the workshop was effective in inspiring the participants to use AM methods and techniques from AM research in their concept generation and whether participants’ AM solutions showed improvement in cost, implementation time, and quality over non-AM designs generated before the workshop.

On the effect of irradiance on dimensional accuracy in multijet fusion additive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mattia Mele ◽  
Giampaolo Campana ◽  
Gian Luca Monti
Keyword(s):  
Additive Manufacturing ◽  
Dimensional Accuracy ◽  
Crystallinity Degree ◽  
Content Type ◽  
Powder Bed ◽  
Polyamide 12 ◽  
Part Density ◽  
The Relationship ◽  
Am Processes

Purpose The amount of radiated energy is known to be a crucial parameter in powder-bed additive manufacturing (AM) processes. The role of irradiance in the multijet fusion (MJF) process has not been addressed by any previous research, despite the key role of this process in the AM industry. The aim of this paper is to explore the relationship between irradiance and dimensional accuracy in MJF. Design/methodology/approach An experimental activity was carried out to map the relationship between irradiance and dimensional accuracy in the MJF transformation of polyamide 12. Two specimens were used to measure the dimensional accuracy on medium and small sizes. The experiment was run using six different levels of irradiance. For each, the crystallinity degree and part density were measured. Findings Irradiance was found to be directly proportional to part density and inversely proportional to crystallinity degree. Higher irradiance leads to an increase in the measured dimensions of parts. This highlights a predominant role of the crystallisation degree and uncontrolled peripherical sintering, in line with the previous literature on other powder-bed AM processes. The results demonstrate that different trends can be observed according to the range of sizes.

Development of an AutoCAD-Based Geometric Tolerancing System

1997 ◽  
Author(s):  
Jhy-Cherng Tsai ◽  
Jing-Sheng Chang
Keyword(s):  
Functional Performance ◽  
Tolerance Analysis ◽  
Manufacturing Cost ◽  
Geometric Dimensioning And Tolerancing ◽  
Geometric Tolerancing ◽  
Interactive Interface ◽  
Dimensioning And Tolerancing ◽  
Frame Transformation ◽  
Tolerance Assignment ◽  
Type Classification

Abstract Geometric tolerancing is an important factor affecting the functional performance and manufacturing cost of a product. Tolerancing specifications have to be assigned with care at design time to reduce the gap between design and manufacturing. This paper describes a system that simplifies tolerancing assignment and uses dimensioning and tolerancing data for related applications. The system consists of five modules for feature type classification, tolerance assignment, tolerance network construction, frame transformation, and tolerance analysis interface. It provides an interactive interface for tolerance assignment based on geometric features that a designer can select from decomposed isometric drawing. The system also recognizes the type of a feature so that only appropriate tolerancing specifications can be assigned. Geometric dimensioning and tolerancing data are used to construct a network for representing the tolerancing and mating relationship among features. The network is then converted for tolerance analysis via a tolerance analysis interface.

scholarly journals Engineering and Economic Aspects of Additive Manufacturing in Energy Related Industries

2020 ◽  
Author(s):  
Sandip Dutta ◽  
Sagar Dasgupta ◽  
Geetha Chimata
Keyword(s):  
Additive Manufacturing ◽  
Complex Geometry ◽  
Production Methods ◽  
Energy Applications ◽  
Recent Developments ◽  
Subtractive Manufacturing ◽  
Manufacturing Methods ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing ◽  
Am Processes

Additive manufacturing is the buzz word these days and many companies are leaning on this technology to leap forward in un-chartered design space that promises to give better performance at impossible to reach design goals with the current manufacturing methods. This paper addresses recent developments that have occurred in Energy related businesses with the adoption of 3D printing, also known as Additive Manufacturing (AM). It covers what and why of additive manufacturing; what constitutes energy and AM industry; current activities in AM for energy; AM for different energy sectors; AM processes; AM applications; selected patents in additive manufacturing associated with energy applications; and economic and financial aspects of AM in energy related industries. In this review paper it was noted that in-spite of phenomenal growth in AM, it seldom replaces traditional production methods due to associated constraints. Many companies are finding complimentary AM processes along with subtractive manufacturing techniques to meet the market demands. However, AM is particularly advantageous and attractive compared to traditional manufacturing methods for low volume complex geometry parts.

scholarly journals The Corrosion of Stainless Steel Made by Additive Manufacturing: A Review

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 516
Author(s):  
Gyeongbin Ko ◽  
Wooseok Kim ◽  
Kyungjung Kwon ◽  
Tae-Kyu Lee
Keyword(s):  
Stainless Steel ◽  
Additive Manufacturing ◽  
Relevant Literature ◽  
Corrosion Property ◽  
Corrosion Study ◽  
Direct Laser ◽  
Manufacturing Methods ◽  
Traditional Manufacturing ◽  
Wire Arc Additive Manufacturing ◽  
Am Processes

The advantages of additive manufacturing (AM) of metals over traditional manufacturing methods have triggered many relevant studies comparing the mechanical properties, corrosion behavior, and microstructure of metals produced by AM or traditional manufacturing methods. This review focuses exclusively on the corrosion property of AM-fabricated stainless steel by comprehensively analyzing the relevant literature. The principles of various AM processes, which have been adopted in the corrosion study of stainless steel, and the corrosion behaviors of stainless steel depending on the AM process, the stainless steel type, and the corrosion environment are summarized. In this comprehensive analysis of relevant literature, we extract dominant experimental factors and the most relevant properties affecting the corrosion of AM-fabricated stainless steel. In selective laser melting, the effects of the scan speed, laser power, energy density, and the post-treatment technologies are usually investigated. In direct laser deposition, the most relevant papers focused on the effect of heat treatments on passive films and the Cr content. There has been no specific trend in the corrosion study of stainless steel that is fabricated by other AM processes, such as wire arc additive manufacturing. Given the rising utilization of AM-produced metal parts, the corrosion issue will be more important in the future, and this review should provide a worthwhile basis for future works.

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