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Song L.,University of Michigan | Bagavath-Singh V.,POM Group, Inc. | Dutta B.,POM Group, Inc. | Mazumder J.,University of Michigan | Mazumder J.,POM Group, Inc.
International Journal of Advanced Manufacturing Technology | Year: 2012

This paper presents a hybrid control system that is able to improve dimensional accuracy of geometrically complex parts manufactured by direct metal deposition process. The melt pool height is monitored by three highspeed charged couple device cameras in a triangulation setup. The melt pool temperature is monitored by a dualcolor pyrometer. A two-input single-output hybrid control system including a master height controller and a slave temperature controller is used to control both height growth and melt pool temperature at each deposition layer. The height controller is a rule-based controller and the temperature controller uses a generalized predictive control algorithm with input constraints. When the melt pool height is above a prescribed layer thickness, the master height controller blocks control actions from the temperature controller and decreases laser power to avoid overbuilding. When the melt pool height is below the prescribed layer thickness, the temperature controller bypasses the height controller and dynamically adjusts laser power to control the melt pool temperature. This hybrid controller is able to achieve stable layer growth by avoiding both overbuilding and under-building through heat input control. A complex 3-D turbine blade with improved geometrical accuracy is demonstrated using the hybrid control system. © Springer-Verlag London Limited 2011.


Dutta B.,POM Group, Inc. | Palaniswamy S.,POM Group, Inc. | Choi J.,University of Michigan | Song L.J.,University of Michigan | Mazumder J.,University of Michigan
Advanced Materials and Processes | Year: 2011

DMD is an enabling technology that allows the right material to be added to the right place, thus adding value to products. A patented closed-loop control adds to the robustness of the process and helps to produce near-netshape parts. The technology has been applied successfully in areas of remanufacturing, hard coating, and new complex part manufacturing. Recent advancements in process sensor technology open up a new horizon for researchers to explore areas of new material synthesis and additive manufacturing of complex geometries.


Bhattacharya S.,University of Michigan | Dinda G.P.,Center for Advanced Technologies | Dasgupta A.K.,Center for Advanced Technologies | Natu H.,POM Group, Inc. | And 3 more authors.
Journal of Alloys and Compounds | Year: 2011

In the current investigation Cu-30Ni alloy was successfully laser deposited on a rolled C71500 plate substrate by Direct Metal Deposition technology. The microstructural investigation of the clad was performed using optical and scanning electron microscopy. The phase and crystal structure analysis was performed using X-ray diffraction technique and transmission electron microscopy. The microstructure consisted of columnar and equiaxed dendrites with face centered cubic crystal structure. The dendrites grew epitaxially from the substrate and layer and bead boundaries. Dendrites' growth direction 〈0 0 1〉 and growth angle 60° was maintained in each layer. The average primary dendritic arm spacing at the bottom part of the layers was about 7.5 μm and average secondary dendritic arm spacing in the upper part of the layer varied between 2 μm and 4.5 μm. The lattice parameter of the identified phase was found to be longer than that reported in literature. The reported lattice parameters in literature are however from samples processed under equilibrium conditions. The microhardness of the clad was found to be less than the substrate but very consistent along the clad. Cu-30Ni clad specimen showed higher ultimate tensile strength but lower yield strength and percentage elongation as compared to the C71500 substrate. DMD Cu-30Ni clad/C71500 substrate specimen showed the worst mechanical properties. The corrosion resistance of the specimens was found to decrease in the order DMD Cu-30Ni clad, half-and-half DMD Cu-30Ni clad-C71500 substrate, and C71500 substrate. © 2011 Elsevier B.V. All rights reserved.


Dinda G.P.,Center for Advanced Technologies | Dasgupta A.K.,Center for Advanced Technologies | Bhattacharya S.,University of Michigan | Natu H.,POM Group, Inc. | And 2 more authors.
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2013

Direct metal deposition (DMD) technology is a laser-aided rapid prototyping method that can be used to fabricate near net shape components from their CAD files. In the present study, a series of Al-Si samples have been deposited by DMD in order to optimize the laser deposition parameters to produce high quality deposit with minimum porosity and maximum deposition rate. This paper presents the microstructural evolution of the as-deposited Al 4047 sample produced with optimized process parameters. Optical, scanning, and transmission electron microscopes have been employed to characterize the microstructure of the deposit. The electron backscattered diffraction method was used to investigate the grain size distribution, grain boundary misorientation, and texture of the deposits. Metallographic investigation revealed that the microstructural morphology strongly varies with the location of the deposit. The layer boundaries consist of equiaxed Si particles distributed in the Al matrix. However, a systematic transition from columnar Al dendrites to equiaxed dendrites has been observed in each layer. The observed variation of the microstructure was correlated with the thermal history and local cooling rate of the melt pool. © 2012 The Minerals, Metals & Materials Society and ASM International.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 149.93K | Year: 2012

ABSTRACT: Direct Digital Manufacturing (DDM) of aircraft metallic components is an emerging and innovative manufacturing process, which can create or repair metallic parts directly from powder metal. DDM promises cost, time and efficiency benefits over traditional machining processes (in which material is removed using cutting tools) in the area of low production volumes, processes involving constant design iterations and manufacturing parts that have relatively complex geometric shapes. For conventional materials, machining processes and material irregularities they cause are well known and any potential failure points or induced stress points that could result in failures have corrective actions to take (e.g. Heat treat). But the newer technologies of additive metal fabrication materials are unknown. We are proposing a research of the required machining processes (Turning, milling, grinding) for final machining of DDM parts and the standardization of these processes to eliminate stress build up or failure points. Phase I research will be restricted to demonstrate the viability of the DDM process by developing machining parameters that will not alter the DDM part microstructures and define metrics for measuring the effectiveness of implementation of the machining parameters and proposed standards, the methodology used, and concept analytical tools produced. BENEFIT: Worldwide market for titanium alone is estimated at $225bn for 2008-2009. Aerospace, being the single largest user in this market, constitutes 56% of the market segment. 16% is for military aerospace market, while commercial aerospace market is the rest 40%. Non-aerospace market, such as medical devices, chemical, automotive, sports industry together constitutes the rest 44% of the titanium market. Last year alone, 5000MTon of titanium has been used in USA in aerospace applications and 90% of this is structural application. Largest single use of titanium is in the aircraft gas turbine engine. In the most modern jet engines, titanium-based alloy parts make up 20% to 30% of the dry weight, primarily in the compressor. The potential market for this technology, specific to metallic aircraft parts for defense application is estimated to be more than $100 millions annually within Northrop Grummen alone, and more than $500 millions industry-wide. Since DMD, a leading DDM process, integrated with proposed machining parameters, achieving improved dimensional accuracy and material integrity described in this proposal, is enabling and certified, it is expected that fundamentally new design concepts and applications could expand the market well beyond $1 billion. To access this market opportunity, POM will offer application and engineering services to introduce new customers to a state-of-the art DMD technology, and to optimize specific processes. Customers will have the option to have POM directly manufacture production parts, or alternatively, to purchase DMD systems.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 78.56K | Year: 2012

In the Navy, severe seawater corrosion is the main cause for damage and failure of high value components in submarine or other vessel components, and weapon systems. While replacement of these components are expensive and time consuming, in-situ repair is challenging due to the geometry constraints by their small bore sizes. Long lead-times and high costs of procuring, inventorying and transporting replacement parts has resulted in a reduction of equipment readiness rates, while DoD operation and support costs have increased. Insertion of additive manufacturing technologies, such as Direct Metal Deposition (DMD) offers an excellent solution to this challenging problem. With its close loop process control and 5-axis deposition capability, DMD allows finer microstructure, shorter heat affected zone, and better mechanical strength of refurbished parts as compared to other open loop processes. This proposal aims to design and develop a new type of wire-based laser cladding nozzle that will be able to meet all the challenges currently facing. Based on POM's extensive past experience in laser cladding nozzle and machine design, a compact nozzle will be designed with quick disconnects for easy and fast mounting/dismounting capability, while a telescopic hardware design will allow deep reach within a short space.


POM Group, Inc. | Entity website

Membership Details Posted in Home Category Tuesday, 24 December 2013 05:55 by Tim Mapes Hits: 7777 DM3D Technology is a proud member of the following Associations/Institutes:


POM Group, Inc. | Entity website


POM Group, Inc. | Entity website

Five plus seven is? (answer as number)


POM Group, Inc. | Entity website

DM3R Details Posted in Production Services & Components Thursday, 26 December 2013 00:08 by Tim Mapes Hits: 24109 MANUFACTURING CHALLENGE Demands for longer life and higher efficiency results in higher wear and tear of components requiring better methods for repairing and re-manufacturing. The need for high performance components for sustainable operations, coupled with the ever increasing cost of materials, has intensified the search for re-manufacturing technologies that offer better quality and a near net shape finish ...

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