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Also known as RCAM, the mission of the center is to promote and apply university led advanced manufacturing research and development work. In order to respond to the industry's needs and to provide the conditions to educate undergraduate and graduate students in the area of manufacturing engineering, the Department of Mechanical Engineering along with SMU School of Engineering established the Research Center for Advanced Manufacturing (RCAM) in September of 1999. Activity within RCAM (Center) lies at the interface between science, engineering, and industrial practice. The Center provides the intellectual foundation for industry to collaborate with faculty and students to resolve generic, long-range challenges, thereby producing the knowledge base for steady advances in technology and their speedy transition to the marketplace.
The Center consists of the following laboratories: Rapid Prototyping and Manufacturing Laboratory, Laser Materials Processing Laboratory, E-beam Materials Processing Laboratory, R&D in Welding Laboratory, Abrasive Waterjet Materials Processing Laboratory, Friction Stir Welding Laboratory, and Materials Characterization Laboratory. The Center is equipped with the most advanced equipment and instrumentation, and is supported by a well equipped machine shop and computing facilities. The Center is housed in the SMU Richardson facility in the space of about 7,000 sq.ft.
The research team has a wide range of technical expertise including the following areas:

Rapid Manufacturing of Functional Parts
Repair of High Value Parts (engine parts, dies, molds, etc.)
High Power Laser in Welding/Surface Modification
Waterjet/Abrasive Waterjet Cutting
Control and Optimization of Welding Processes
Application of Friction Stir Welding
Integration of Machine Vision Systems for Monitoring and Controlling Different Processes
Integration of Different Positioning Systems, Sensors and Controllers
Numerical Analysis: ANSYS Software
Material flow simulation of polymers (MoldFlow Software).
Application of CAD Software: Pro-E, SolidWorks, AutoCad.
Application Software: C, C++, Assembly Language, LABVIEW, MATLAB
Materials Science: SEM, X-Ray Diffraction, Metallographic Characterization
Development of Control Systems Based on Neural Networks and Fuzzy Logic

The Southern Methodist University Research Center for Advanced Manufacturing (RCAM) has recently filed invention disclosures (1 and 2 in the list below) for sensing technologies for variable polarity plasma arc welding (VPPAW) and friction stir welding (FSW) respectively. These sensing technologies would markedly improve the quality control and performance of these processes used by aerospace industries and others. While these new systems have been proven by RCAM to be effective sensing techniques, the laboratory devices currently used are in the prototype stage. Further hardware development and refinement of the analysis and control software will be required to create market-ready systems.

The set of technologies described in disclosures 3 through 10 will enable RCAM to develop, along with an industry partner, the Multi Fabrication (MultiFabTM) system for rapid manufacturing and repair. RCAM has been working intensively on the development of a hybrid SFF system based on deposition by welding and multi-axis CNC milling for the last several years. The ultimate goal is to incorporate laser-based additive manufacturing (LBAM) or 3D laser cladding in this hybrid SFF system. The outcome of this integration will lead to the development of a multi functional processing system called MultiFabTM. This will be a production system that will provide the most concentrated part creation ability in the world. In the same setup on one computer-controlled MultiFabTM system platform, the following operations could be performed: two additive operations (deposition of metal by welding-base and laser-based additive process), subtractive operations (CNC milling, drilling), scanning for reverse engineering, and post-processing inspection. The MultiFabTM system will be characterized by the advantages of both deposition processes. Welding-based deposition is characterized by one order faster metal deposition rate than laser-based deposition which is reflected in its ability to build larger structures in a much shorter time. Laser-based deposition is characterized by the ability to build finer geometrical features with a smaller heat affected zone, less porosity, multiple material compositions, better control of material properties, and the possibility to deposit metal powder in any direction. The combination of these two deposition processes with multi-axis CNC milling provides the capability to make complex internal and external geometrical features, and to achieve high dimensional accuracy and surface quality.

The ten invention disclosures recently filed by Southern Methodist University Research Center for Advanced Manufacturing (RCAM) are described briefly below:

Two-Sided Image Sensor for Monitoring Keyhole in Variable Polarity Plasma Arc Welding: This is a new system to increase the accuracy of the front-side image-based measurement of the keyhole size in the variable polarity plasma arc welding (VPPAW) of aluminum alloys. For the typical equipment used in VPPAW, the welding torch and the base metal block the view of the keyhole portion of the welding pool, thereby limiting the field of view. This complicates the acquisition of images from the front side of the workpiece. In order to solve this problem, RCAM has developed a novel optical device to acquire keyhole welding pool images simultaneously from two sides of the plasma arc-welding torch. Currently, there are no commercially available image sensing systems capable of providing consistent, high-quality feedback for the VPPAW process. The new system would augment the viability of VPPAW for various industrial welding applications.

On-Line Monitoring of Quality of Weld and Tool Conditions in Friction Stir Welding: This system can be used for the on-line monitoring of the friction stir welding (FSW) process. Using two rolling acoustic sensors, two preamlifiers, and an acoustic emission analysis tool, acoustic emissions (AE) derived from the release of stress in the welded material as well as those derived from the friction between the tool and the material together are recorded and analyzed to reveal the existence, location and size of material defects, as well as tool wear and breakage. These capabilities are of obvious use to the aircraft and aerospace industries, which are currently developing FSW as a revolutionary time and cost-saving joining process.

Method for Controlling the Operational Welding Parameters in Welding-Based Deposition Process: This disclosure describes an apparatus and method for producing parts by a welding-based deposition process. A component is fabricated by a computer-controlled deposition process which deposits a succession of overlying beads. This method differs from previous methods in that the welding parameters are calculated as a function of the volume of the heat sink below and around the weld bead at all times during the deposition.

Apparatus and Method for Rapid Manufacturing of 3D Aluminum Parts: RCAM has developed a novel deposition process for directly building axisymmetric parts of aluminum alloys using variable polarity gas tungsten arc welding (VPGTAW). A machine vision sensor is used to monitor and control the arc length, which is a key welding parameter in the creation of a uniform deposition process. Overheating of the metal during part creation is avoided by optimizing the deposition rate and the thickness of the deposited layers, thus obviating the need for a cooling system for the welding stage. This system is capable of producing three-dimensional parts with smooth and uniform surfaces and good material properties.

Powder Feeder for Low Flow Rates: Laser-based additive manufacturing (LBAM) requires precise control over the metal, ceramic, or carbide powder added to the molten pool. The feeding rate of the powder must be very consistent, and it must respond rapidly to commands to change the feeding rate. LBAM also requires feeding rates as low as one gram per minute. Currently, commercially available powder feeders are optimized for such tasks as feeding powder to thermal spraying processes, which generally require a much higher feeding rate than LBAM, and can usually tolerate much more variation in the feeding rate. These powder feeders are therefore not suitable for the LBAM process. This disclosure describes a new powder feeder capable of consistent, repeatable powder delivery at extremely small flow rates. The powder feeder can be regulated by a variety of feedback systems.

Apparatus and Method for Controlling Multiple Powder Feeding Systems: Functionally Gradient Material (FGM) fabrication requires the control of multiple metal/ceramics powder feeding systems, so that the delivery rates of different kinds of powder can be adjusted in real-time to obtain the desired compositions. RCAM has designed a new embedded powder feeder controller that controls an individual powder feeder, and is capable of regulating the powder delivery rate by a weight-based or optoelectronic-based feedback system. Several of these controllers (up to four) can be linked to a central PC to create a control system for multiple powder feeding systems.

Apparatus and Method for Controlling the Size of Molten Pool in Laser-Based Additive Manufacturing: Laser-based additive manufacturing (LBAM) requires a stable and controllable process. The size of the molten pool is critical to the results of the LBAM process, which for instance affect geometrical accuracy and material microstructure. Currently, no commercial system is available for controlling the size of the molten pool in LBAM. RCAM has designed and built a closed-loop control system based on infrared image sensing for controlling the size of the molten pool in the LBAM process. A high frame-rate camera is installed coaxially on the top of the laser-nozzle setup. The laser output power is controlled based on the feedback from the infrared image. A stable and controllable molten pool can thus be achieved during the LBAM process, greatly improving the geometrical accuracy of parts, and simultaneously providing the desired microstructure.

Design of a Friction Stir Welding Tool for Welding High Melting Temperature Materials: This disclosure describes a new friction stir welding tool which will be able to weld higher melting point materials such as titanium, stainless steel, and nickel alloys. The new tool is based on the idea of functional gradience, in which the material constitution and properties of the tool at any point within and on the surface of the tool are optimized for the thermophysical stresses at that point. RCAM builds these tools layer-by-layer, using a laser-based additive manufacturing (LBAM) process, which uses a high-powered Nd:YAG laser and a combination of two or more powder feeders to create a tool with a surface of very heat and abrasion-resistant material and a functionally graded tool body. Such tools have superior abrasion resistance, but the welding of some high-melting-temperature materials requires active control of the heat within the tool. The RCAM-LBAM process is also capable of building conformal cooling channels into the tool as it is built, to allow the tool to be liquid cooled as it is used.

A Solid Freeform Fabrication Process Based on the Plasma Transferable Arc Powder Deposition

Assisted by a High Power Laser: This disclosure describes a novel method for directly building metallic parts, which may include ceramic and carbide constituents, using plasma transferable arc powder deposition technology combined with a high-power laser beam to produce three-dimensional parts in a layer-by-layer additive manufacturing process. This method is capable of producing parts with functional gradience, in which the material constitution and properties of the part at any point within and on the surface of the part are optimized for the thermo-physical stresses at that point. Using a laser beam which passes coaxially through the plasma torch, the combined system exhibits the greatly increased deposition rates which are typical of the plasma transferable arc powder deposition system while maintaining the fine control over the molten pool size and its location.

Multi Fabrication (MultiFab) System for Rapid Manufacturing/Repair

The Research Center for Advanced Manufacturing has been developing the multi fabrication (MultiFab) system for rapid manufacturing/repair. In the same setup on one computer-controlled production platform, the following operations will be performed: three additive operations (deposition by welding-based processes (GMAW, GTAW), deposition by plasma powder cladding, and multi-axis CNC machining (milling, drilling, etc.), scanning for reverse engineering and post-processing inspection. Welding-based and plasma-based deposition is characterized by one order of the magnitude faster metal deposition rate than laser-based deposition. However, laser-based deposition is characterized by the ability to build finer geometrical features with a smaller heat affected zone, multiple material composition (functionally graded structures), better control of material properties, and possibility to deposit metal powder in any direction. The combination of these deposition processes with multiple axis CNC machining provides the capability to make complex internal and external geometrical features, and to achieve high dimensional accuracy and surface quality.