Automatic polishing process of plastic injection molds on a 5-axis milling center

The plastic injection mold manufacturing process includes polishing operations when surface roughness is critical or mirror effect is required to produce transparent parts. This polishing operation is mainly carried out manually by skilled workers of subcontractor companies. In this paper, we propose an automatic polishing technique on a 5-axis milling center in order to use the same means of production from machining to polishing and reduce the costs. We develop special algorithms to compute 5-axis cutter locations on free-form cavities in order to imitate the skills of the workers. These are based on both filling curves and trochoidal curves. The polishing force is ensured by the compliance of the passive tool itself and set-up by calibration between displacement and force based on a force sensor. The compliance of the tool helps to avoid kinematical error effects on the part during 5-axis tool movements. The effectiveness of the method in terms of the surface roughness quality and the simplicity of implementation is shown through experiments on a 5-axis machining center with a rotary and tilt table

Segmentation and Coverage Planning of Freeform Geometries for Robotic Surface Finishing

Surface finishing such as grinding or polishing is a time-consuming task, involves health risks for humans and is still largely performed by hand. Due to the high curvatures of complex geometries, different areas of the surface cannot be optimally reached by a simple strategy using a tool with a relatively large and flat finishing disk. In this paper, a planning method is presented that uses a variable contact point on the finishing disk as an additional degree of freedom. Different strategies for covering the workpiece surface are used to optimize the surface finishing process and ensure the coverage of concave areas. Therefore, an automatic segmentation method is developed to find areas with a uniform machining strategy based on the exact tool and workpiece geometry. Further, a method for planning coverage paths is presented, in which the contact area is modeled to realize an adaptive spacing between path lines. The approach was evaluated in simulation and practical experiments on the DLR SARA robot. The results show high coverage for complex freeform geometry and that adaptive spacing can optimize the overall process by reducing uncovered gaps and overlaps between coverage lines

Micro/Nano Manufacturing

Micro manufacturing involves dealing with the fabrication of structures in the size range of 0.1 to 1000 µm. The scope of nano manufacturing extends the size range of manufactured features to even smaller length scales—below 100 nm. A strict borderline between micro and nano manufacturing can hardly be drawn, such that both domains are treated as complementary and mutually beneficial within a closely interconnected scientific community. Both micro and nano manufacturing can be considered as important enablers for high-end products. This Special Issue of Applied Sciences is dedicated to recent advances in research and development within the field of micro and nano manufacturing. The included papers report recent findings and advances in manufacturing technologies for producing products with micro and nano scale features and structures as well as applications underpinned by the advances in these technologies

The Development of Automatic On-Machine Metrology

The manufacture of large off-axis aspheric optics for the next generation of extremely large telescopes presents a number of unique challenges. For example, the European Southern Observatory (ESO) Extremely Large Telescope (E-ELT) requires the manufacture of one 1.4 m class ultra-precision mirror segment per week in order to satisfy the first-light deadline. One of the factors limiting the pace of manufacture is metrology. Many of the tasks associated with measurement, such as optic positioning, alignment and acquisition are carried out manually. It is also common for the optic to be removed to a laboratory for measurement, which can be time consuming and risk damage. This thesis presents research into the development of new on-machine metrology techniques, which allow measurement to be carried out in the manufacturing environment. This work is supported by a software application developed by the author to allow the design and control of on-machine metrology. This application uses the computer numerical control (CNC) polishing system as part of the positioning and alignment system. The inclusion of CNC has enabled the development of a close-loop control system which facilitates automatic alignment and acquisition of metrology data. The software presented uses a modular architecture, allowing many different types of metrology to be planned and control using a single application. This is demonstrated using two case studies, which allow automatic on-machine sub-aperture stitching metrology using a metrology tower placed over the machine, and automatic on-machine texture measurement. The use of a closed loop software application to control automatic on-machine texture measurement is a novel step. It is also demonstrated that on-machine metrology in the manufacturing environment can produce measurement data of comparable quality to that of the laboratory. Automatic measurements systems such as those presented are likely to play an increasing role in the large and high-volume optical fabrication sectors

Low-Cost Inventions and Patents

Inventions have led to the technological advances of mankind. There are inventions of all kinds, some of which have lasted hundreds of years or even longer. Low-cost technologies are expected to be easy to build, have little or no energy consumption, and be easy to maintain and operate. The use of sustainable technologies is essential in order to move towards a greater global coverage of technology, and therefore to improve human quality of life. Low-cost products always respond to a specific need, even if no in-depth analysis of the situation or possible solutions has been carried out. It is a consensus in all industrialized countries that patents have a decisive influence on the organization of the economy, as they are a key element in promoting technological innovation. Patents must aim to promote the technological development of countries, starting from their industrial situations

Cold Micro Metal Forming

This open access book contains the research report of the Collaborative Research Center “Micro Cold Forming” (SFB 747) of the University of Bremen, Germany. The topical research focus lies on new methods and processes for a mastered mass production of micro parts which are smaller than 1mm (by forming in batch size higher than one million). The target audience primarily comprises research experts and practitioners in production engineering, but the book may also be of interest to graduate students alike

Determination of Process Parameters for the Manufacturing of Thermoplastic Composite Cones Using Automated Fiber Placement

In-situ fiber placement, in combination with automated tape laying and filament winding, is the key to high-volume production of large-scale composite aerostructures ranging from simple flat plates, to panels with mild curvatures, to complex three-dimensional surfaces, promising reliable, consistent and cost-effective fabrication. However, manufacturing cost, slit tape quality, lack of knowledge and experience of the in-situ consolidation fiber placement process are major barriers preventing aircraft manufacturer from implementing this unique processing technique. This dissertation aims to gain knowledge and experience of in-situ consolidation fiber placement by identifying and resolving four technical issues associated with the manufacturing of thermoplastic composite tailbooms. The first study demonstrates that the percentage of gap/lap and the angular deviation of fiber orientation can be controlled by dividing a single tool surface to multiple and equal sections. The second study shows that the interlaminar defects have minimal effects on the mechanical properties of autoclave molded thermoplastic composite laminates. The third study predicates a set of optimum processing parameters for manufacturing tailboom demonstration articles using automated fiber placement. The last study suggests that the in-situ consolidation fiber placement process needs to be improved to lower the micro-size void content and minimize the process induced warpage

Special Issue of the Manufacturing Engineering Society (MES)

This book derives from the Special Issue of the Manufacturing Engineering Society (MES) that was launched as a Special Issue of the journal Materials. The 48 contributions, published in this book, explore the evolution of traditional manufacturing models toward the new requirements of the Manufacturing Industry 4.0 and present cutting-edge advances in the field of Manufacturing Engineering focusing on additive manufacturing and 3D printing, advances and innovations in manufacturing processes, sustainable and green manufacturing, manufacturing systems (machines, equipment and tooling), metrology and quality in manufacturing, Industry 4.0, product lifecycle management (PLM) technologies, and production planning and risks

Workshop Proceedings: Optical Systems Technology for Space Astrophysics in the 21st Century, volume 3

A technology development program, Astrotech 21, is being proposed by NASA to enable the launching of the next generation of space astrophysical observatories during the years 1995-2015. Astrotech 21 is being planned and will ultimately be implemented jointly by the Astrophysics Division of the Office of Space Science and Applications and the Space Directorate of the Office of Aeronautics and Space Technology. A summary of the Astrotech 21 Optical Systems Technology Workshop is presented. The goal of the workshop was to identify areas of development within advanced optical systems that require technology advances in order to meet the science goals of the Astrotech 21 mission set, and to recommend a coherent development program to achieve the required capabilities

NASA SBIR abstracts of 1990 phase 1 projects

The research objectives of the 280 projects placed under contract in the National Aeronautics and Space Administration (NASA) 1990 Small Business Innovation Research (SBIR) Phase 1 program are described. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses in response to NASA's 1990 SBIR Phase 1 Program Solicitation. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 280, in order of its appearance in the body of the report. The document also includes Appendixes to provide additional information about the SBIR program and permit cross-reference in the 1990 Phase 1 projects by company name, location by state, principal investigator, NASA field center responsible for management of each project, and NASA contract number