Typical Mechanical Part Research Articles

Feature-based energy consumption quantitation strategy for complex additive manufacturing parts

Additive manufacturing (AM) has significant advantages, including design freedom, mass customization, and complex-structure manufacturing capabilities. As reducing the manufacturing energy is challenging in terms of the industrial sustainability, the AM energy consumption must be further explored. Existing energy consumption quantitation methods for AM require complex models that considering the energy characteristics of equipment. Therefore, we propose a feature-based energy consumption quantitation method for complex AM parts using simple models and suitable for different AM technologies. First, a feature segmentation method is proposed to divide complex AM parts into typical AM features. Then, the energy consumption model for each AMF is developed for energy consumption quantification during part fabrication. Finally, the energy consumption of a typical mechanical part manufactured via three different AM processes is investigated using the proposed method and measured experimentally. The results show that the proposed method can effectively and rapidly predict the energy consumption of AM processes with an accuracy of more than 95 %. Furthermore, the efficiency of the three AM processes is compared and discussed to address suitable efficiency improvement methods. In general, the proposed method can be integrated into three-dimensional AM models, providing a reference for the structural optimization of AM parts and sustainable manufacturing.

Methodology for integrated additive-subtractive process chain generation

The production share of laser powder bed fusion increases in industrial application and single piece and small series production are core markets. Still, many process steps in the field of additive manufacturing are manually operated, especially in post-processing. Additionally, it is not possible to achieve tight dimensional tolerances or low surface roughness which are necessary for typical mechanical parts. Hence, a process chain has to be set up to combine the design flexibility and function integration capabilities of AM with further machining technologies to achieve workpiece requirements. As L-PBF has some particular properties and process parameters influencing post-processing, an individual approach for process chain generation is needed. These properties and parameters are, in particular, support structures and free positioning options within the build chamber of the AM machine. Both properties have a major influence to post-processing and have to be addressed in machine selection, clamping options, processing steps and workpiece description. The approach shows how an additive manufactured workpiece can be described taking into account the complex part consisting of workpiece, support structures and substrate plate. Further, kinematic limitations for further processing are added as meta-information and workpiece requirements and machine performances are compared for a manufacturing process selection for further processing. Based on technological and economical parameters a manufacturing process selection is performed. Finally, improved parameters are suggested to optimize the L-PBF process with regard to further processing. So, the L-PBF process design can combine AM parameters with further processing parameters to improve the whole process chain. The methodology shall be implemented in a software tool to simplify the practical application.

Cost, resources, and energy efficiency of additive manufacturing

Additive manufacturing (AM) is the process of joining materials to make objects from Computer Aided Design (CAD) model data, usually layer upon layer, as opposed to using subtractive manufacturing methods. The use of rapid prototyping technologies has increased significantly in recent years. These new techniques, while still evolving, are projected to exert a profound impact on manufacturing. They can reduce energy use and time to market and offer industry new design flexibility. We include a brief study on the cost and energy efficiency of selected methods of additive manufacturing compared to traditional methods of manufacturing parts. One common claim is that 3D printers are more energy-efficient than other manufacturing technologies. We present energy efficiency and time requirements for producing a typical mechanical part and a very complicated element, using both traditional manufacturing and rapid prototyping methods. This paper represents an attempt to answer the questions of when 3D printing can be used efficiently and of choosing the appropriate technology on the basis of batch size, element size, complexity, and material requirements.

Fusion of Multi-Vision of Industrial Robot in MAS-Based Smart Space

The paper presents a fusion method of muti-vision of industrial robot in a smart space based on multi-agent system(MAS), the robotic multi-vision consists of top-view, side-view, front-view and hand-eye cameras, the moving hand-eye provide vision guidance and give the estimation of robot position, other three cameras are used for target recognition and positioning. Each camera is connected to an agent based on an image-processing computer that aims at analyzing image rapidly and satisfying the real-time requirement of data processing. As a learning strategy of robotic vision, a back-propagation neural network(BPNN) with 3-layer-architecture is first constructed for each agent and is independently trained as a classifier of target recognition using batch gradient descent method based on the region features extracted from the images of target samples(typical mechanical parts), and then the outputs of trained BPNNs in MAS-based smart space are fused with Dempster-Shafer evidence theory to form a final recognition decision, the experimental results of typical mechanical parts show that fusion of multi-vision can improve the robotic vision accuracy and MAS-based smart space will contribute to the parallel processing of immense image data in robotic multi-vision system.

A Reliable Wireless Sensor System for Monitoring Mechanical Wear-Out of Parts

A ball screw is a typical mechanical part that experiences wear-out and is widely used in computer numerical control machine tools to control the movement of processing targets and spindles. These types of parts need frequent checks so that they are replaced before excessive wear occurs. Until now, there was no simple way to measure directly the state of wear quantitatively. An indirect approach is logging the signals (vibration, temperature, and preload change) during the operation of mechanical parts. This information can be used to construct a wear model for estimating its remaining lifetime. For embedding sensors into mechanical devices, wireless sensors bring advantages in that they may be installed freely without constraints from data or power cables. However, wireless transmission is subjected to interference. To make wireless sensors that can be used practically within an industrial environment, we propose a wireless sensor system that: 1) emphasizes low-power and low cost in hardware design; 2) logs the signals during the operation of a mechanical part that could experience wear; and 3) guarantees that all the logged data can be wirelessly delivered to the data server. To our knowledge, this is the first wireless sensor system for measurement of mechanical operation signals that guarantees complete data delivery and correctness. We designed, implemented, and evaluated this system in real environments. This ensures that the design is practical. We envision that a miniature version of our design could be embedded in the ball screw shaft and gearbox reducer for logging signals to enable the building of a wear model to estimate the part's lifetime.

Geometrical nonlinearity stabilizes a wave solid-state gyro

It was recognized long ago that quasi-harmonic standing waves in a thin-walled axisymmetric resonator, mounted on a rotating platform, are subject to a precession. This significant phenomenon is naturally associated with a concept of a solid-state wave gyro, or an inertial instrument used to measure angular rotation rate, as if any wave may be interpreted as a material particle moving in a rotating frame of reference. Because there are no typical mechanical parts, these wave sensors can be utilized with a lot of advantages. To run such a gyro in vita, one should excite and keep on by certain means a standing wave in the thin-walled axisymmetric resonator. Up to now, there are known two ways how to do it, and namely, using either external or parametric resonant mechanisms of excitation. Although both cases necessarily require an additional feedback control device in order to stabilize instable or other parasite oscillations of the resonator. This paper, following the study of nonlinear waves in a thin circular ring, demonstrates that the solid-state wave gyro may be naturally stabilized just at the expense of the geometrical nonlinearity by combining advantages of both the positional resonant excitation and the parametric resonance.

Approach Toward Parametric Design of Typical Parts and Parts-Library Based on UG

With the basic tool of the powerful secondary development function of UG NX and based on the analysis of the characteristics of typical mechanical parts, put forward a digital method and system of parametric design for the parts, created the relavent parts-library for the system. In the parametric design, mechanical parts were divided roughly into four classes according to GT. The characteristic parameters were selected from the shared attributes of each class. By utilizing the secondary development tool of UG/Open, compiled, connected by means of Visual C++, and realized the integration of a mechanical-part orientated UG system for parametric design with user-friendly interface and counterpart dynamic-link library files. Taking characteristic parameters of typical parts as the variables, different models were established through man-computer interaction according to size constraint, and then created the parts-library. The system has worked successfully taking the inner gear as example of the typical part, and given expected result. It is shown from the execution of system that the current system with the virtual parts-library can respond the designer's demand fast, avoid repetition, save manpower and time, and improve the speed of new product development significantly.

Development of Parametric CAD System Based on Pro / Toolkit and Database Technology

With Pro/Toolkit of Pro/E and ADO(ActiveX Data Object) database technology, part parametric CAD system is developed and an successful instance is introduced in the paper. In the CAD system, interface between Pro/E and VC++6.0 is created correctly using Pro / Toolkit and user interface for part parametric designing can be achieved by means of dll( dll dynamic link) library built in VC++6.0 .Meanwhile ADO database is applied in the CAD system to manage all part parameters and thus part revising and updating can be realized quickly. The developing method in the CAD system not only is applicable to typical mechanical part designing but also be helpful to establishing standard part library.

Geometric assistance for visual reasoning and construction of solids with curved surfaces from 2D orthographic views

As the extensive use of solid models becomes widespread, it is important to have a mechanism by which existing engineering drawings can be converted into solid models. Therefore, a geometric assistance that can aid in visual reasoning and constructing of solid models is beneficial. In this paper, we present key operations for a system called the Assistant for Reasoning and Construction of Solids (ARCS), which provides this assistance given a set of two orthographic views. The geometric domain of ARCS encompasses curved solids with cylindrical and spherical surfaces, such as those found in typical mechanical parts. We have devised the Cylindrical and Spherical Warping operations to create cylindrical and spherical surfaces, which use interactive computer graphics that guide a human user to curved faces of a solid. These operations are then illustrated with examples using ARCS to create the solid models of typical mechanical parts from their orthographic projections.

Algorithms for computing the volume and other integral properties of solids. II. A family of algorithms based on representation conversion and cellular approximation

This paper discusses a family of algorithms for computing the volume, moments of inertia, and other integral properties of geometrically complex solids, e.g. typical mechanical parts. The algorithms produce approximate decompositions of solids into cuboid cells whose integral properties are easy to compute. The paper focuses on versions of the algorithms which operate on solids represented by Constructive Solid Geometry (CSG), i.e., as set-theoretical combinations of primitive solid “building blocks.” Two known algorithms are summarized and a new algorithm is presented. The efficiencies and accuracies of the three algorithms are analyzed theoretically and compared experimentally. The new algorithm uses recursive subdivision to convert CSG representations of complex solids into approximate cellular decompositions based on variably sized blocks. Experimental data show that the new algorithm is efficient and has predictable accuracy. It also has other potential applications, e.g., in producing approximate octree representations of complex solids and in robot navigation.

Orienting Mechanical Parts by Computer-Controlled Manipulator

In order to assemble mechanical parts which are initially disordered, a computer-controlled manipulator needs some procedure for orienting these parts. An apparatus is described which assists the manipulator in performing this function. The device is a dihedrally tipped open box attached to a vibrator. When placed in the box, a typical mechanical part assumes one of a small finite number of possible orientations. Once the particular orientation is established, the manipulator shifts the part into the desired orientation.