Machine Issues Associated with Solid Freeform Fabrication

Before we begin a discussion of machine issues it is important that we categorize exactly what we mean. There are differences between the design of a research piece of equipment as compared to a commercial piece of equipment. A research piece of equipment has to have the flexibility to demonstrate a success pattern. A commercial piece of equipment, on the other hand, assumes that you have a stable platform and you are now trying to assess how broad a success path you have (Figure 1). In fact, you are trying to make that path as broad as possible so that the machine will not fail and will always work the same way. This particular talk, and my expertise, is much more along the lines of design of a research piece of equipment. What I will be talking about today are machine issues associated with developing a success path in Solid Freeform Fabrication. The machines we will be talking about have to have the flexibility to operate in a wide variety of ways with a wide variety of experiments.Mechanical Engineerin

Application of Factorial Design in Selective Laser Sintering

Selective Laser Sintering (SLS) is a complex process involving many process parameters. These parameters are not all independent. A factorial design technique is utilized to study the effects of three main process parameters, laser power, laser beam scanning speed, and powder packing density as well as their interactions on the sintering depth and fractional density. The results of this investigation provide useful information for the further experimental analysis of the process parameters and for selecting suitable parameters for SLS process.Mechanical Engineerin

Laser Polishing of Silica Rods

Lasers have been widely used in surface modification. In this research a CO2 continuous wave laser has been used to polish the slot surface of the silica rods. The strong absorption of the lO.6 um C02 radiation by the silica surface promotes the softening of a very thin layer of material that flows under the action of surface tension. As a result, a mirror smooth glassy surface has been formed which decreases the surface roughness without any substantial change in the surface geometries. The effect of laser to surface inclination angle on the requisite power requirement was assessed experimentally and theoretically. With laser beam scanning controlled by a computer aided design (CAD) database without specific tooling or human intervention, reliability and reproducibility of this process have been greatly improved compared to conventional fire polishing. The potential use of laser polishing as a post-processing step for freeform-fabricated parts is very promising.Mechanical Engineerin

Support-Free Infiltration of Selective Laser Sintered (SLS) Silicon Carbide Preforms

Non-metallic objects are often difficult to manufacture due to high melting temperatures, poor sinterability, limited ductility, and difficulty in machining. Freeform fabrication techniques coupled with liquid infiltration offer a cost-effective and rapid manufacturing mechanism for composite parts with complex geometry and adequate properties. Selective laser sintered (SLS) silicon carbide (SiC) preforms infiltrated with liquid silicon develop localized infiltrant overextrusions onto surfaces and at surface irregularities. Several shrinkage mechanisms including densification were studied as possible causes of these overfilling extrusions, and the results are discussed below. This research was supported by NSF Grant Number DMI-0522176.Mechanical Engineerin

A Model for Partial Viscous Sintering

A mathematical model describing the sintering rate of a viscous material powder bed is presented. This model assumes that the powder bed is composed of cubic packed, equal-size spherical particles. The sintering rate equation is derived in terms of a unit cell dimension or the relative density of a powder bed. A mathematical factor, fraction of sintering, is introduced to explain the phenomena of partial sintering. Key words: model, viscous sintering.Mechanical Engineerin

Solid Freeform Fabrication: An Historical Perspective

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Rescue the Clinical Nurse Educator with a Transformative Mentorship Program

The purpose of this project was to develop a transformative mentorship program for clinical nurse educators. Jean Watson’s Theory of Human Caring (THC) was used as the theoretical framework for the development of this program. The population for this evidenced-based project was 12 clinical nurse educators who work in a private baccalaureate liberal arts college. These educators provide supervision for students in the hospital as well as community clinical practice settings. This evidence-based project examined if the implementation of a mentorship program would help increase the confidence level of the clinical educator. The project was implemented over a three-month period with the delivery of power points through the college’s platform to the clinical educators. The topics presented within the power points included commonly encountered challenges faced by clinical educators and strategies for solutions to these challenges. Opportunities were provided throughout the three-month period for debriefing regarding any questions or comments related to the topics presented in the power points. The Confidence Scale (C-scale) developed by Susan Grundy was administered to the clinical educators as a pre-test prior to the mentorship program and as a post-test following completion of the program. The scale was used to determine if the educator’s confidence increased. The Wilcoxon signed ranks test was used to determine if there was a significant difference in C-Scale item scores before and after participation in the mentorship program. Two of the five C-Scale items were significant at the .05 level of significance. There was sufficient evidence to support an increase in confidence level in performance and satisfaction with performance post-implementation. Post implementation data collection also consisted of Evaluation of the Mentorship Program to provide additional data regarding the value of the mentorship program. All participants felt that the program was effective and provided them with opportunities to examine challenges of the clinical nurse educator role. Experienced nurse educators have a responsibility to mentor future educators as they transition from clinicians to the role of a nurse educator. Effective clinical nurse educators facilitate quality clinical practice for nursing students, which is a priority in the nursing profession. The practice of effective nurses for the future is mainly dependent upon the present practices of role modeling observed by students in the clinical setting (Cunze, 2016). A mentorship program that uses experienced nurse educators who value qualities of transformative mentoring provides a solution to help in the successful growth and retention of nursing faculty

Teaching a Human Rights Education Through Youth Athletics

Throughout my research and work in education I realized there is often a disconnect between schooling and students especially in low-income areas. It can be incredibly difficult to feel confident at school when the curriculum is not relatable to your experiences and life. In this paper I explore how an athletic program can be used to teach a Human Rights Education to fill in the gaps the traditional school day may not provide. I used a Human Rights Education framework with the teacher/coach as a facilitator and a Critical Race Theory lens examining intersectionality, counter-story telling, and interest convergence in the school day. I interviewed 14 students at two different urban elementary schools who take part in a “junior coach” leadership program to get an oral history perspective on their lives, experiences in school, and how sports impacted them. Based on my findings I provide recommendations on how best a coach, teacher, team, and community can support and empower students to solve community problems and inspire students to follow their dreams. In the Appendix there are some sample lesson/practice plans on how a coach can use a Human Rights Education at a sports practice

SLS Materials Development Method for Rapid Manufacturing

As soon as SFF technology development began to make Rapid Prototyping possible the interest in Rapid Manufacturing (RM) began to grow. The advantages in terms of functional integration, elimination of tooling and fixtures and mass customization make a compelling case for RM, leading some in the field to call it the next industrial revolution. Yet without the materials properties necessary to provide the function and variety currently available from mass production methods, the application of RM will remain limited. Developing new materials for the SLS process, one immediate step toward a larger portfolio of RM materials, is very challenging. The formation of high quality SLS parts relies on appropriate powder characteristics, thermal cycles and sintering behavior. Based on a brief examination of the key factors in SLS processing and a research project to develop a new binder material for Silicon Carbide composites, a systematic materials development method is proposed in this paper. The method provides guidance for introducing new SLS materials, support for educating new SLS users and researchers and direction for several future research projects.Mechanical Engineerin