Automated freeform assembly of threaded fasteners

Over the past two decades, a major part of the manufacturing and assembly market has been driven by its customer requirements. Increasing customer demand for personalised products create the demand for smaller batch sizes, shorter production times, lower costs, and the flexibility to produce families of products - or different parts - with the same sets of equipment. Consequently, manufacturing companies have deployed various automation systems and production strategies to improve their resource efficiency and move towards right-first-time production. However, many of these automated systems, which are involved with robot-based, repeatable assembly automation, require component- specific fixtures for accurate positioning and extensive robot programming, to achieve flexibility in their production. Threaded fastening operations are widely used in assembly. In high-volume production, the fastening processes are commonly automated using jigs, fixtures, and semi-automated tools. This form of automation delivers reliable assembly results at the expense of flexibility and requires component variability to be adequately controlled. On the other hand, in low- volume, high- value manufacturing, fastening processes are typically carried out manually by skilled workers. This research is aimed at addressing the aforementioned issues by developing a freeform automated threaded fastener assembly system that uses 3D visual guidance. The proof-of-concept system developed focuses on picking up fasteners from clutter, identifying a hole feature in an imprecisely positioned target component and carry out torque-controlled fastening. This approach has achieved flexibility and adaptability without the use of dedicated fixtures and robot programming. This research also investigates and evaluates different 3D imaging technology to identify the suitable technology required for fastener assembly in a non-structured industrial environment. The proposed solution utilises the commercially available technologies to enhance the precision and speed of identification of components for assembly processes, thereby improving and validating the possibility of reliably implementing this solution for industrial applications. As a part of this research, a number of novel algorithms are developed to robustly identify assembly components located in a random environment by enhancing the existing methods and technologies within the domain of the fastening processes. A bolt identification algorithm was developed to identify bolts located in a random clutter by enhancing the existing surface-based matching algorithm. A novel hole feature identification algorithm was developed to detect threaded holes and identify its size and location in 3D. The developed bolt and feature identification algorithms are robust and has sub-millimetre accuracy required to perform successful fastener assembly in industrial conditions. In addition, the processing time required for these identification algorithms - to identify and localise bolts and hole features - is less than a second, thereby increasing the speed of fastener assembly

The 29th Aerospace Mechanisms Symposium

The proceedings of the 29th Aerospace Mechanisms Symposium, which was hosted by NASA Johnson Space Center and held at the South Shore Harbour Conference Facility on May 17-19, 1995, are reported. Technological areas covered include actuators, aerospace mechanism applications for ground support equipment, lubricants, pointing mechanisms joints, bearings, release devices, booms, robotic mechanisms, and other mechanisms for spacecraft

The 24th Aerospace Mechanisms Symposium

The proceedings of the symposium are reported. Technological areas covered include actuators, aerospace mechanism applications for ground support equipment, lubricants, latches, connectors, and other mechanisms for large space structures

The 21st Aerospace Mechanisms Symposium

During the symposium technical topics addressed included deployable structures, electromagnetic devices, tribology, actuators, latching devices, positioning mechanisms, robotic manipulators, and automated mechanisms synthesis. A summary of the 20th Aerospace Mechanisms Symposium panel discussions is included as an appendix. However, panel discussions on robotics for space and large space structures which were held are not presented herein

NASA Tech Briefs, July 1992

Topics include: New Product Ideas; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

The 31st Aerospace Mechanisms Symposium

The proceedings of the 31st Aerospace Mechanisms Symposium are reported. Topics covered include: robotics, deployment mechanisms, bearings, actuators, scanners, boom and antenna release, and test equipment. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms

Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Technology 2001: The Second National Technology Transfer Conference and Exposition, volume 2

Proceedings of the workshop are presented. The mission of the conference was to transfer advanced technologies developed by the Federal government, its contractors, and other high-tech organizations to U.S. industries for their use in developing new or improved products and processes. Volume two presents papers on the following topics: materials science, robotics, test and measurement, advanced manufacturing, artificial intelligence, biotechnology, electronics, and software engineering

Design And Analysis Of Mechanical Mating Interfaces For Reconfigurable Machine Tools

Reconfigurable Machine Tools (RMTs) which are designed under modularity concept are a new approach in machine tools technology which is characterized by customized flexibility to serve current production requirements. It allows changes in machine physical configuration whenever required. This concept of machine tools is still under development stage. Even though there are numbers of design methodologies proposed, there is no method specifically mentioned on how each module would be assembled together. Using a structured design approach, the newly design of mechanical mating interface method is proposed. Two non-vertex cones with pin-slot arrangement were found to be the best concept. Using Finite Element Method (FEM), the detail design on the optimum design variables was determined. The stiffer assembly was assured when the ratio of depth of penetration to the total mating interface thickness used is 0.6. The 1/10 tapered angle was the best value for the cones and 0.15 mm of the face clearance between mating interfaces ensured 5μm of interference fit. Using simulation modelling, the performance of the newly designed mating interface was investigated and compared with conventional interface method. The newly designed mating interfaces were confirmed to perform better compared to conventional method. Finally, the tolerance analysis was conducted and appropriate tolerance values were allocated. The intended interference fit of the assembled modules was achieved

Demanufacturing metrics for industrial fasteners and disassembly process

As the society progresses towards ecological maturity, the issue of reducing the environmental burden imposed by used products becomes increasingly important Environmental issues are becoming increasingly relevant for product designers and manufacturers. Public awareness of the value and fragility of an intact ecology is constantly growing, and the traditional assumption that the cost of ecological burdens to be shared by a society, as a whole is no longer accepted. Environmental protection legislation requiring manufacturers to take back and recycle used products will be a commonplace throughout Europe and the U.S. in the near future. Demanufacturing involves separating and disassembling a \u27product\u27 into its smaller \u27subassemblies\u27 and \u27components\u27. Unfastening carries out the physical separation itself and other separation techniques are also used to separate the unfastened component. There are two types of Disassembly methods they are destructive disassembly and non-destructive. The term \u27product\u27 means a complete entity, such as an automobile, a washing machine, etc. \u27Sub-assembly\u27 refers to a product .A \u27component\u27 is a subassembly that cannot be disassembled any further. The principle aims and objectives of this research are to analyze the mechanical aspects of demanufacturing a component with respect to fasteners and disassembly Processes. This research involved developing Disassembly Effort Index Metrics (DEIM) for a wide variety of industrial fasteners, destructive and non destructive disassembly processes. The industrial Fasteners were separated into four categories i.e. One Piece Fasteners, Two Piece Fasteners, Integral Fasteners and Miscellaneous Fasteners. They were analyzed with respect to the accessibility of a fastener with respect to the part, tools necessary to disassemble them, time needed to unfasten them, part hold and fixturing issues ,forces needed to unfasten them and instructions to the dissemblers to dissemble the fastener. A scoring pattern was developed. The Disassembly Processes were categorized into Non-Destructive Disassembly and Destructive Disassembly. The Non-Destructive Disassembly methods like Magnetic Separation, Suction and Drainage, Self Removal, Separation of both Fastened and Unfastened Components, and only two of the Destructive Disassembly methods i.e. Weld Breakage and Impact breakage were analyzed using Disassembly Effort Index Metrics (DEIM) parameters. The DEIM parameters, for the Disassembly Processes are, time needed to disassemble the component, tools needed to separate them, Forces (both human and Machine), Part hold , Process Instructions and Hazard Tools. The scoring pattern was developed