On the Use of Angled, Dynamic Laser Beams to Improve Stereolithography Surface Finish

Improved surface finish of Stereolithography (SLA) parts is an important goal for furthering the resolution of the technology. In order to improve the surface finish, a dynamic laser beam with changing angle, beam size, beam shape, and irradiance distribution is proposed. In this paper, an analytical irradiance model of an angled, dynamic laser beam in the SLA process is presented. This model is used to simulate cured shapes of SLA builds. Simulated build shapes are compared to established SLA analytical models and conclusions are drawn on the accuracy of the developed model.Mechanical Engineerin

Use of Parameter Estimation for Stereolithography Surface Finish Improvement

In order to improve Stereolithography (SLA) surface finish, a systematic approach based on estimation of process parameters is needed. In this paper, the exposure on a desired SLA build surface is formulated as a function of process parameters. The deviation of exposure on this surface from the critical exposure, which is the threshold that determines curing in the SLA process, is formulated using least squares minimization. By applying inverse design techniques, SLA process parameters that satisfy this least squares minimization are determined. Application of parameter estimation formulation to important SLA geometries is presented and the results, including surface finish improvement, are discussed.Mechanical Engineerin

Stereolithography Process Resolution

To build smaller parts in StereoLithography (SL) and detect some build errors before fabrication, a good understanding of process resolution is needed. A categorization of resolution factors into process-inherent and software-induced categories is presented in the paper. Results from several experiments testing different aspects of SL resolution illustrate the effects of these factors. A method based on offsetting algorithms is presented to determine as-built part crosssections and aid detection of possible build errors. A method that will enhance build resolution of SL parts is proposed.Mechanical Engineerin

Experimental Studies in Stereolithography Resolution

As we move towards micron-scale rapid manufacturing, it is critical to understand build resolution of Stereolithography technology. In order to determine the resolution limitations, positive and negative features on Stereolithography parts were built and analyzed. Results from several experiments were compared to an analytical model and important resolution issues are highlighted. Based on these experimental results, parameters that will maximize build resolution for a number of well-understood shapes are suggested in the paper. Build resolution experimental results, analysis, and measurement techniques are discussed. Conclusions are drawn related to feature shape as resolution limits are approached.We gratefully acknowledge the support from the RPMI member companies and the George W. Woodruff School of Mechanical Engineering at Georgia Tech. This work was partially funded by the National Science Foundation under Grant Number DMI-9988664.Mechanical Engineerin

Stereolithography Characterization for Surface Finish Improvement: Inverse Design Methods for Process Planning

To facilitate the transition of Stereolithography (SLA) into the manufacturing domain and to increase its appeal to the micro manufacturing industry, process repeatability and surface finish need to be improved. Researchers have mostly focused on improving SLA surface finish within the capabilities of commercially available SLA machines. The capabilities of these machines are limited and a machine-specific approach for improving surface finish is based purely on empirical data. In order to improve surface finish of the SLA process, a more systematic approach that will incorporate process parameters is needed. To achieve this, the contribution of different laser and process parameters, such as laser beam angle, irradiance distribution, and scan speed, to SLA resolution and indirectly to surface finish, need to be quantified and incorporated into an analytical model. In response, a dynamic analytical SLA cure model has been developed. This model has been applied to SLA geometries of interest. Using flat surfaces, the efficacy of the model has been computationally and experimentally demonstrated. The model has been applied to process planning as a computational inverse design method by using parameter estimation techniques, where surface finish improvement on slanted surfaces has been achieved. The efficacy of this model and its improvement over the traditional cure models has been demonstrated computationally and experimentally. Based on the experimental results, use of the analytical model in process planning achieves an order of magnitude improvement in surface roughness average of SLA parts. The intellectual contributions of this research are the development of an analytical SLA cure model and the application of this model to process planning along with inverse design techniques for parameter estimation and subsequent surface finish improvement.Ph.D.Committee Chair: Dr. David W. Rosen; Committee Member: Dr. Ali Adibi; Committee Member: Dr. Cliff Henderson; Committee Member: Dr. Farrokh Mistree; Committee Member: Dr. W. Jack Lacke

A method for understanding and predicting stereolithography resolution

M.S.David W. Rose

Implications of a Multi-Disciplinary Educational and Research Environment: Perspectives of Future Business, Law, Science, and Engineering Professionals

Functioning well in a global, technology-driven, multi-disciplinary environment necessitates a more robust educational paradigm in science and engineering. For a technical education to be complete, it is no longer enough to train scientists and engineers solely in technical areas. There are clear shortcomings in academic curricula that need to be addressed in order to bring about this required paradigm shift. Much the same is true for students of law and business, who will have to understand many of the technological underpinnings and corresponding implications to impart their perspectives. While it is true that multi-disciplinary education and innovation programs are starting to surface, the question of “how the participants’ experiences will influence future career plans and personal goals’ is largely unanswered. Our focus in this paper is the importance of understanding social, economic, and legal aspects of science and engineering within the context of graduate-level education. Specifically, the authors take a closer look at the TI:GER (Technological Innovation: Generating Economic Results) program from the participants’ perspective. TI:GER is a multi-disciplinary program between Georgia Institute of Technology and Emory University, focused on integrating science, engineering, business, and law for the commercialization of innovations in the global marketplace. Based on their experiences, the authors present their learning and insight on multi-disciplinary education in a mixed technical and professional degree setting

SRL Research Overview - Rosen's Students

Presentation given for SRL meeting Summer 200