Integration of On-Machine Measurements in the Force Modeling for Machining of Advanced Nickel-Based Superalloys

Nickel-based superalloys are specially designed for applications where high strength, creep resistance, and oxidation resistance are critical at high temperatures. Many of their applications are the hot gas sections of turbo-machinery (e.g. jet engines and gas turbines). With greater demands on the performance and efficiency of these types of machines, the firing temperatures are reaching higher levels and nickel-based superalloys are being utilized more because of their excellent mechanical qualities at extreme temperatures. However, the properties that make them attractive for these applications present difficult challenges for the manufacture, particularly machining, of the components that are made from these materials. Considering the extreme environment that these components operate in, part quality, in particular surface quality, is paramount. The damage and stresses introduced to the surfaces of these components during manufacture needs to be well understood and controlled in order to ensure that premature component and machine failures do not occur. With improved process models and on-machine measurement capabilities, the in-process cutting forces and temperatures can be better understood and therefore subsurface damage can be better controlled. Since cutting forces and temperatures are direct contributors to subsurface damage, better control of these aspects would then lead to better control of subsurface damage. This paper discusses the use of on-machine touch probes to measure wear on milling tools and using those measurements to update a mechanistic force model for more accurate prediction of the cutting forces incurred during the milling of nickel-based superalloys.

Job Shop Scheduling to Meet Due Dates With Consideration to Sequence Dependent Setup Times in a Dynamic Environment

In this paper, we propose a dynamic job shop scheduling method to minimize tardiness with consideration to sequence dependent setup times. Schedules are optimized on a rolling basis using the mixture of genetic algorithm and switching priority rules. Both in genetic algorithm and switching rules, schedules are generated to increase due date allowances to be robust in dynamic environment. Numerical experiments show the effectiveness of the proposed method.

Direct Digital Additive Manufacturing and Cyber-Enabled Manufacturing Systems

The technology of direct digital additive manufacturing (D2AM) has received considerable attention in recent months. Several government agencies and commercial interests are planning to explore D2AM to find solutions to manufacturing problems. The attraction of D2AM is the benefit of rapidly producing without fixtures or tools or human intervention customized objects of complex geometry not possible by traditional methods. The interest in D2AM ranges from fabrication of critical, high value aerospace metallic components to fabrication of objects having an organic look or as nature would have intendedi. For D2AM to be commercially accepted, it must reliably and predictably make products. It must achieve consistency in reproducibility across relevant D2AM methods. The Office of Naval Research (ONR) has launched a new basic research program, known as Cyber-enabled Manufacturing Systems (CeMS). The long-range goal of the program is to achieve the level of control over D2AM processes for industrial acceptance and wide-use of the technology. This program will develop measuring, sensing and control models and algorithms for D2AM by harnessing principles underpinning cyber-physical systems (CPS) and fundamentals of physical processes. This paper describes the challenges facing D2AM and the CeMS program goals to meet them.

A Case Study in 3D Printed Porous Ceramics: Infant Incubator Humidification System

This paper describes research in adapting 3D printers to operate with low-cost ceramic materials. The components produced with these clay-based ceramic powders can be fired to produce strong, complex and lightweight ceramic parts. The final material properties, including the porosity of the parts, can be controlled through the part design and, potentially, through additives to the material that burn out during firing. The paper begins with a brief description of the 3D printing process and how it can be used with clay powders. It then introduces a factorial design experiment initiated to explore the effect of ingredient and parameter variations on the dimensional stability and material properties of green and fired ceramic parts. It then presents a case study in which 3D printed ceramic parts are used in the humidification system for an infant incubator for developing countries.

A Simple Inverter-Motor System to Improve Energy Consumption and Maximum Torque

A new inverter-AC motor system having four power source lines, which can control each coil current independently, is compared to an ordinary inverter-AC motor system using a Y-type coil connection and three power lines. In this paper, three-phase rectangular-type currents are generated by the inverter made of simple ICs. In a previous paper[1], similar comparison experiments were executed using a high-speed DSP board. The board can calculate the three-phase currents to generate a rotating, resultant, magnetic flux with a precise constant strength and phase. It was verified by experiments that an energy consumption of 15% can be saved by using the proposed independent, motor-coil currents. However, it requires high speed and high cost DSP or CPU. In this paper, it is verified by using a new inverter-AC motor system that an energy consumption of 15% can be saved, and also the maximum torque increases 10%.

A Multimodal Environment for the Simulation and Training of Maintenance Operations: A Case Study

The paper describes the development of a multimodal environment that can be used as a tool to train operators to perform maintenance tasks of industrial products during their lifecycle. The environment provides a visual and haptic representation of a product through the use of commercially-available hardware and software technologies. The new environment mixes interactive simulations of products, based on Virtual Reality technologies, and the information included in the traditional instruction manuals. The paper discusses about what can be effectively simulated with the available technology, and how the current technological limitations can be overcome by using the potentialities offered by a multimodal approach. Technology limitations can also be overcome by mixing two different strategies for coupling parts: the physics-based and the constraint-based approach. A case study provided by a company working in the field of household appliances has been used to prove the concept, to develop, test and finally refine the multimodal environment. The paper describes the development of the multimodal environment and presents the results of the user tests.

Technologizing and Digitalizing of Medical Professional Skills for a Non-Invasive Ultrasound Theragnostic System

Information and robot technology (IRT) is drawing increasing attention in the technologizing and digitalizing of medical professional skills. In fields such as manufacturing, high-precision tasks, not possible with human, skills have been already realized by industrial robots. The medical field thus expected to advance with progress in the development of medical robots able to provide diagnosis and therapy that are much more precise than those of conventional medical professionals.

Job-Shop Scheduling Approach to Order-Picking Problem

In recent years, a large-scale logistic center plays an important role in mail-order business with Internet. In the logistic center, the efficient managing is required to deliver products to customers as soon as possible. Researches to efficiently control the logistic center have been done in the various approaches. This study proposed a new method for the order-picking problem considering worker’s jamming at the same shelf in the logistic center. In the proposed method, we formulate worker’s scheduling in the logistic center as Job-shop Scheduling Problem and optimize this problem. Numerical experiments show the proposed method improve worker’s scheduling compared with rule-based scheduling.

Electric Vehicle Drivetrain Development in China

Despite great progress recently made on applications of in-wheel motors in electric vehicles, almost all production or near-production electric vehicles still utilize mechanical speed reduction systems for transferring torque from the traction motor to wheels for the purposes of torque augmentation and speed reduction. These systems in general fall into three categories, i.e. fixed ratio, stepped variable ratio, or continuously variable ratio. In China, most electric cars retrofitted from internal combustion engine propelled vehicle models use gear reduction systems of a fixed speed ratio, in order to minimize the time to market. Typically a conversion is made to the original 5-speed manual transmission by taking out a few unused gear sets. With the rapid growth in electric vehicle industry, some gearboxes of fixed speed have been engineered and they typically have a layshaft configuration. Most of them still do not come with a “park” gear due to a lack of understanding on customer’s needs. As an exception, a transmission of fixed speed ratio dedicated for electric vehicle applications has been developed at the Electric Vehicle R&D Center, Chinese Academy of Sciences (UCAS). Among electric vehicles announced by domestic vehicle manufacturers in China, some employ 5-speed manual transmissions (MTs) or automatic transmission (ATs) that typically found in traditional vehicles. From the driving convenience, transmission efficiency, or cost standpoints, these transmissions are, in general, not appropriate for applications in electric vehicles. The “misusage” of these transmissions has often something to do with their availability rather than suitability. A great deal of effort has been put into the research and development of automated mechanical transmissions (AMTs) in China to date. Significant progress has been made to the reduction of shift time, improvement of shift quality, and optimization of the mechanical components. Continuously variable transmission (CVT) is considered to be an important trend in drivetrain technology. However, the pulley-belt types of CVT commonly seen in traditional vehicles are not proper for electric vehicle applications. An EVT dedicated for electric vehicles is under development at UCAS, in which the power from an electric motor of dual-rotors is coupled by means of a planetary gear set, allowing continuous variable of the output speed. In summary, the electric vehicle drivetrain technology in China is undergoing rapid advances, which will impact the development of electric vehicle industry at home and abroad.

A Method for Efficient Flexible Process Planning by Mathematical Optimization

Computer support technology for modern manufacturing should deal with variable situations to accomodate to high-mix low-volume manufacturing. Computer-aided process planning (CAPP) has been discussed from this point of view, and a method for flexible CAPP, which generates a new proper process plan easily when manufacturing situation has changed, was proposed for rough milling by a three-axis vertical machine. This method was enhanced to handle millings by a multiaxis vertical machine and by both vertical and horizontal machines. The basic idea of these methods is to generate all process plans and then choose the best one. In the choice process of the best plan, all of the generated plans are evaluated. However, this process requires a large computational power when employed in actual machining where products of complex shapes have to be produced. For this computational problem, this paper discusses application of the mathematical optimization framework to this choice process.