Metal Parts Generation by Three Dimensional Printing

Mechanical Engineerin

Injection Drug Use Among West Virginia Medicaid Beneficiaries: An Analysis of Health Outcomes, Service Utilization, and Cost

In the United States, injection drug use is a serious public health concern associated with an array of negative health outcomes and substantial financial consequences for systems of care. The purpose of this study was to characterize a statewide sample of Medicaid insured persons who inject drugs in terms of health outcomes, service utilization and cost. A cross-sectional, retrospective analysis of West Virginia Medicaid claims data between 2014 and 2016 was conducted. Between 2014 and 2016, 5,082 West Virginia Medicaid beneficiaries amassed 14,414 service visits, among which inpatient, emergency room, and mental health and substance abuse were the most common. Drug poisonings (n=5,077), soft-tissue infections (n=4,127) and other infectious diseases (n=2,141) were the most common clinical conditions within this sample. Medicaid claims data were not a suitable proxy for state surveillance data as it pertains to new cases of Hepatitis B, Hepatitis C, HIV and heroin overdoses. Ordinal logistic regression results indicate that infectious diseases like endocarditis and soft-tissue infections are associated with increased service utilization. Similarly, multiple regression models show increased cost among individuals with HIV, endocarditis, and Hepatitis B. Preventative services, e.g. syringe exchange programs, are important tools to reducing the spread of infectious diseases, and thereby decrease frequent service utilization and cost among injection drug users

Production of Injection Molding Tooling with Conformal Cooling Channels using The Three Dimensional Printing Process

Three Dimensional Printing is a desktop manufacturing process in which powdered materials are deposited in layers and selectively joined with binder from an ink-jet style printhead. Unbound powder is removed upon process completion, leaving a three dimensional part. Stainless steel injection molding inserts have been created from metal powder with the 3DP process. The freedom to create internal geometry by the use of the 3D-Printing process allows for the fabrication of molds with complex internal cooling passages. Tooling was developed with cooling channels designed to be conformal to the molding cavity. A finite difference simulation was constructed to study conformal channel design. A direct comparison of the mold surface temperature during the injection cycle of a 3D Printed mold with conformal channels and a mold machined with conventional straight channels was completed. The conformal passages produced with the 3DP process provide the ability to accurately control the temperature of the molding cavity throughout the process cycle. Surface temperature measurements demonstrated that the inserts with conformal cooling channels exhibited a more uniform surface temperature than the inserts machined with straight channels. Issues such as powder removal and post processing of green parts with small cooling channels were investigated.Mechanical Engineerin

Three Dimensional Printing of Tungsten Carbide-Cobalt Using a Cobalt Oxide Precursor

Tungsten Carbide 10 wt% Cobalt parts were formed by Slurry-based Three Dimensional Printing (3DPTM). The slurry contained a mixture of Tungsten Carbide and Cobalt Oxide powders, as well as dispersing and redispersing agents. The cobalt oxide is fully reduced to cobalt metal during the early stages of the sintering process. A new binder system, polyethylenimine, is described for use with powders with acidic surfaces, such as WC. Sintered densities approach the theoretical values for WC-10% Co, and the microstructures produced are similar to those of conventionally processed (press and sinter) materials. Up to four parts were produced in a single print run using a layer thickness of 25 Pm, with good dimensional agreement between them, and within the range of target dimensions after sintering.Mechanical Engineerin

Toward Manufacturing of Fine Components by 3D Printing 191

Solid Freeform Fabrication has earned its place in the industrial practice of prototyping and is beginning to have an impact in the fabrication of tooling. The next and perhaps greatest opportunity for SFF lies on the direct manufacture of components. This paper will present efforts directed toward the MANUFACTURE IN HIGH QUANTITY of small, precision components by 3D Printing. The primary focus is on ceramic and ceramic/metal components, although all metal components are envisioned as well. The production of small, fine-featured parts presents two opportunities for a new machine architecture. First, the powderbeds required for small parts are themselves small and lightweight. Thus, a machine can be designed where powderbeds move from the layer spreading station to the print station and back again. Multiple powder beds can be in play, taking full advantage of all stations of the machine. The second opportunity is to define the perimeter of the part using vector motions of a nozzle with the interior filled by raster scanning. Such an approach has the advantage that the boundary of the part will be defined as a smooth contour. Moving powderbeds and vector printing are combined in the linear shuttle-type machine for research purposes. Ultimately, a rotary machine is envisioned for high production.Mechanical Engineerin

Modeling and Designing Components with Locally Controlled Composition

SFF processes have demonstrated the ability to produce parts with locally controlled composition. In the limit, processes such as 3D Printing,cancreate parts with composition control on thelength scaleiof 100 microns.ToexploitthispC)tential,~e\\ZJnethodsto rnod~l, exchange, and process parts.with local composition needtobe.deyeloped..... Anapproachtc) modeling a part's geometty,.topology, and composition will be presented.· This.approachis based on sUbdividing the solidmodel into sub-regions and associating analytic composition blending functions \\lith each region. These blending functions definethe composition throughout the model as mixtures ofthe primary materials available to·the SEF machine. Various design tools will also be presented, for example, specification of com~ositionasa function of the distance from the surface of a part. Finally,the role of design rules specifying maximum concentrations and concentration.gradients will be discussed.Mechanical Engineerin

Progress on Tooling by 3D Printing; Conformal Cooling, Dimensional Control, Surface Finish and Hardness

Three Dimensional Printing is being applied to the direct fabrication of tooling using metal powders. This paper presents progress updates in four areas: i) thermal management using conformal cooling and related work on enhanced heat transfer using surface textures, ii) data on dimensional control, iii) ) improvements in surface finish, and iv) harder tooling. Conformal cooling has demonstrated significantly improved performance in a production part geometry with simultaneous gains in production rate and part quality obtained as measured against conventional tooling. Surface textures printed on cooling channels have demonstrated 8X enhancement of heat transfer over smooth channels. A set of 18 tooling inserts was fabricated using hardenable stainless steel powder with a resultant tooling hardness of 25-30 Rockwell C. Harder alloy systems are being designed with the aid of computational thermodynamic tools which allow accurate prediction of the interaction of powder and binder. Significant improvements in surface finish were obtained using improved printing technology. Dimensional control of tools conformed well to the expected result of being dominated by control of shrinkage and being predictable to within ±.25%.Mechanical Engineerin

In Vivo rapid delivery of vasopressin from an implantable drug delivery micro-electro-mechanical device

A miniaturized implantable rapid drug delivery device based on micro-electro-mechanical-systems technology was recently developed and characterized. This device is intended to address acute conditions in high-risk subjects. This work provides an in vivo proof-of-concept for the device in a rabbit model, by releasing a physiologically active dose of vasopressin, a vasoconstrictor. The devices were implanted subcutaneously and activated to rapidly release vasopressin, with monitoring of mean arterial pressure and plasma levels.Device releases showed a rapid and measurable effect on mean arterial pressure as well as a continuous diffusion of vasopressin into the bloodstream, consistent with a depot effect. Plasma levels in rabbits receiving vasopressin with the device rose monotonically to 24.4 ± 2.9 ng/mL after one hour. Bioavailability after one hour was calculated to be 6.2 ± 2.8 % (mean ± s.d.).A new modality for rapid and controlled drug delivery has been developed. The device can be used as a new implantable device controlled by medical algorithms (based on heart rate or mean arterial pressure, for example) for autonomous operation in high-risk populations that require immediate ambulatory intervention.Keywords: Subcutaneous drug delivery; vasopressin; MEMS; rabbit; bioavailability

In Vivo rapid delivery of vasopressin from an implantable drug delivery micro-electro-mechanical device

A miniaturized implantable rapid drug delivery device based on micro-electro-mechanical-systems technology was recently developed and characterized. This device is intended to address acute conditions in high-risk subjects. This work provides an in vivo proof-of-concept for the device in a rabbit model, by releasing a physiologically active dose of vasopressin, a vasoconstrictor. The devices were implanted subcutaneously and activated to rapidly release vasopressin, with monitoring of mean arterial pressure and plasma levels.Device releases showed a rapid and measurable effect on mean arterial pressure as well as a continuous diffusion of vasopressin into the bloodstream, consistent with a depot effect. Plasma levels in rabbits receiving vasopressin with the device rose monotonically to 24.4 ± 2.9 ng/mL after one hour. Bioavailability after one hour was calculated to be 6.2 ± 2.8 % (mean ± s.d.).A new modality for rapid and controlled drug delivery has been developed. The device can be used as a new implantable device controlled by medical algorithms (based on heart rate or mean arterial pressure, for example) for autonomous operation in high-risk populations that require immediate ambulatory intervention.Keywords: Subcutaneous drug delivery; vasopressin; MEMS; rabbit; bioavailability

Zero-order controlled release of ciprofloxacin-HCl from a reservoir-based, bioresorbable and elastomeric device

A reservoir-based device constructed of a completely biodegradable elastomer can enable several new implantation and insertion options for localized drug therapy, particularly in the case of urological therapies. We performed an in vitro performance evaluation of an implantable, bio-resorbable device that supplies short-term controlled release of ciprofloxacin-HCl (CIP). The proposed device functions through a combination of osmosis and diffusion mechanisms to release CIP for short-term therapies of a few weeks duration. Poly(glycerol-co-sebacic acid) (PGS) was cast in a tubular geometry with solid drug powder packed into its core and a micro-machined release orifice drilled through its wall. Drug release experiments were performed to determine the effective release rate from a single orifice and the range of orifice sizes in which controlled zero-order release was the main form of drug expulsion from the device. It is demonstrated that PGS is sufficiently permeable to water to allow the design of an elementary osmotic pump for drug delivery. Indeed, PGS's water permeability is several orders of magnitude larger than commonly used cellulose acetate for elementary osmotic pumps.Deshpande Center for Technological InnovationSamsung Scholarship Foundatio