Advanced manufacturing technologies - Article Example

Running Head: ADVANCED MANUFACTURING TECHNOLOGY Due to increased advancement in technology in various fields such as electronics, and medicine among others manufacturing engineers have advanced their techniques to cater for increasing demand in these other fields of technology. The complexities in manufacturing of parts required by the technologists in specialties such as medicine has necessitated development of various advanced manufacturing techniques. This paper seeks to outline Layered Manufacturing Technology (LM), Rapid Prototyping (RP) and other techniques used in advanced manufacturing technology in details. It will also establish the correlation between the technology and medicine; that is the use of the technology in manufacture of implants. Lastly the paper will discuss the details of reverse engineering technology as applied in Computer Aided Design (CAD). 354345 Advanced Manufacturing Technology: Introduction Advanced manufacturing technology is aspect of advancement in manufacturing technology that enables development of composites and composite materials that are beneficial to manufactures in the market. On the other hand it enhances productivity, efficiency and excellent quality of products manufactured. There are various aspects in the place of advanced manufacturing technology, which include Layered Manufacturing Technology, Computer Numerical Control among others. The Layered manufacturing technology has proved to be very diverse and in application and more so in the field of medicine. This technology though easy to implement since it does not require he contemporary tools needs a very skilled and knowledgeable know-how to implement if the desired results have to be obtained. This technology constitutes of various techniques that include Selective Laser Sintering (SLS), Selective Laser Melting (SLM) and Electron Beam Melting (EBM). Layered Manufacturing Technology Layered manufacturing technology (LM) can be defined as production of solid materials in laminated form. This technology of material production can be carried out using various methods but all of them apply the same idea of principle. In the process of manufacture the three-dimension design of the object to be produced should be well described with respect to its dimension. This is then formatted to give the slice; that is the layers in terms of their definite size and numbers so that they can be assembled together to form the solid material wanted. They are several technologies that are applicable in combination of the said layers or slices in this technology to come up with a solid object, thus this technology is perceived as construction of a definite solid shape from individual building units of given size. This technology as described, has some positive aspects to the technologists employing them; that is It makes the tools, moulds or dies usage not necessary. On the other hand the technologist can easily manipulate the quality of the surface finish of the object being manufactured Although the limitation to this technology is that the rate of manufacturing objects is slower than other methods of manufacturing which uses tools, moulds or dies and depends on the method used. This method of manufacturing in perception of the basic principle can be related to the following manufacturing methods. The layers are like bricks used by masons in constructions of objects of different required shapes. Clay threads layered together to form walls that will produce an object of required shape and size in pottery. Use of slices in expressing three-dimensional landscape in cartography. The big difference between layered manufacturing technology and above practices is that the units used in t LM technology are considerably very small to the tune of 10-100 microns. LM technology was developed from Rapid Prototyping (RP) technology, which involves high-speed production of patterns that are hard to produce using contemporary tools. Layered Manufacturing Techniques There are various techniques used in LM technology which include; SLS, SLM and EBM. History and Development The history of development of Layered Manufacturing Technology processes is notably dated 30 years ago. Before the evolution of the additive manufacturing technology these processes were simply known as rapid prototyping since it involved mass production of prototypes without having to use tools or other traditional processes of manufacturing (Wohlers, 2009). Selective Laser Sintering (SLS) In this method of LM technology the solid materials required are produced on a computer panel by sintering powder material on it. This method is useful since it does not require tools in fabrication of some parts and also it can be applied in production of parts that are complex in shape. However the method is limited to the mechanical strength and the texture of the material produced by its processes. The performance of this method is mainly affected by the scanning path's generation and the way the path is controlled (Jia, Bin Hong-Zan B & Zhang Xiao-Bo, 2002). Selective Laser Melting (SLM) This method fabricates solid objects by fusion of melted metal powder in layers by use of computer programs. SLM employs a 40-micron spot fiber laser to join metal powder into a solid object. The powder is fused using a computer program which scans cross-sections from the Computer Aided Design (CAD) model on the part manufactured on powder bed, addition of layers is done continually after each is laid on the bed to produce the desired shape. In SLM the fabricating platforms are pre heated to avoid cracking in some alloys. Apart from prototyping SLM is also applicable in Product development modeling Manufacture of high value components Production of representative structures Production of complex shapes Reverse engineering This method is mostly applicable to Aluminum silicon alloy and Stainless steel (TWI. Technology Engineering, 2008). A diagram indicating the process of selective laser melting The above four diagrams manufactured by the SLM method shows the complexity of the parts.( McLaren, 2006). Electron Beam Melting (EBM) Acram AB founded EBM technology in Sweden. This is additive method of layered manufacturing technology metal powder is melted and fused together in layers by use of an electron beam. This method produce very strong parts which are free of voids an advantage over the sintering methods. EBM is also computer based manufacturing method with the EBM machine obtaining data from CADS model and adding together layers as per the design. A computer process, which uses electron beam to melt and join layers together in a vacuum, is used in EBM to build parts of different shapes. The main alloys in the application of this technology are Titanium alloys mostly in medicine to manufacture medical implants. (Kruth, Lieu & Nakagawa, 1998). Alloys and other Materials Suitable for LM processes Research is continuously being conducted to realize various materials that are best suited for the layered manufacturing processes. The most popular alloys suitable for the SLS, SLM, and EBM processes currently are; Cobalt Chromium Inconel 625 Inconel 718 Maraging Steel 15-5 and 17-4 Stainless Steel. Titanium Ti6Alv4 Aluminum silicone Apatite Application of the prototypes, their level of surface finish and tolerance The application of parts produced by these parts is in the manufacture of parts with very complex geometry, very small sized components and production of tool inserts. The industries include dental, medical, aerospace and others. These prototypes have usually a high level of surface finish due to the use of CAD in generation of models. Geometrical tolerance of the prototypes is very finite for the same reason (Wohlers, 2009). Standard Triangulation Language (STL) Tool File Techniques The STL tool file is a computing application in manufacturing technology, which employs various techniques and methods interchangeably. These methods include; Rapid Prototyping (RP) Rapid Tooling (RT) Layered Manufacturing Technology (LM) Computer Aided Design (CAD) Direct Digital Manufacturing (DDM) Rapid prototyping This is a technique that is employed to produce components that may be of complex shapes or tiny and numerous to be produced by the ordinary manufacturing methods. This technique is one of the layered manufacturing technologies whereby physical solid object is built from layers that are joined together from the data in the 3-D and CAD models. This means that the digital tool employed in creating parts layer by layer builds objects without molding casting or machining (LIOU, 2007). Rapid Tooling Due to the efficiency of rapid prototyping in production of complex shapes, manufactures have adopted it in rapid tooling (RP) which is the production of tools dies or moulds by applying the RP technology. Tools moulds and dies whose purpose is also manufacturing may require more advanced technology in their production owing to the possibility of complexity in shape size and more so the need to have quality surface finish. (Geng, 2008) Layered Manufacturing As discussed earlier this is an aspect of advanced manufacturing technology that encompasses various techniques such as RP, SLS, SLM and EBM. Computer Aided Design CAD is the general term for the application of computers in design of objects in manufacturing. This technology involves production of virtual production of model shapes specifying dimensions, tolerances and processes that can be simulated to manufacture a real object. CAD as an STL file tool builds a model on the data that is used by the manufacturing system to produce the desired component. The whole system of using computers in manufacturing is denoted Computer Aide Manufacturing (CAM) which includes CAD. Due to the complexities in techniques like Rapid prototyping CAD is a necessity. Direct Digital Manufacturing. This technique also is interchangeably used with the word 3-D printing or it is simply rapid prototyping that shows objects directly from the 3D CAD files. It also employs additive building methods in manufacture of objects. The above technologies of manufacture have various advantages over the contemporary methods which include Ability to manufacture complex geometry parts. There is extremely very low wastage of materials used in manufacture when employing these methods. Only the layering energy is required in the manufacture hence there is almost perfect energy saving. There is no requirement of moulds tools or dies hence the design and production of part is fast from the time it is designed. Bio-Medical Materials and Implants: History Development Biomedical materials are materials that are suitable for use by medical doctors and surgeons in their practice. They should be light, compatible with structural and the biological function of the body system and easy to produce. They include; Titanium alloys Apatite (Calcium compound Silicon compounds for example Aluminum Silicone A device that is used to substitute a biological structure, complement it or support it is referred to as a medical implant. a) b) c) This diagram shows a) hemi- knee joint implant b) supported by titanium implant, c) as implant on femur bone. (.He, Li & Lu 2006). History and development Though primitively: implants have been used by different communities hundreds of years before this date. Dental prosthesis was found in a skeleton of a woman in a Roman tomb by researchers. These ancient implants were sometimes more of aesthetic than medical in their purpose. In the 16th century Gotz Von Berlichingen used an artificial arm. Implants are artificial devices made of either metallic or composite materials contrary to transplants, which are biological tissues that are used for the same purpose. A material is said to be biomedical compatible if in the event of its use as an implant material it does not react with the body tissues or cells negatively. Examples of materials that are excellent in biomedicine compatibility are apatite, titanium or silicone, which depends on the usage of each. Implants are not only limited to mechanical aspect of devices but can also be electronic depending on its function, for example cochlear implants and the artificial pacemaker, which is an implant in the heart. The most used implants today are dental implants and the orthopedic implants. (Bidanda, & Bartolo, 2007). Dental Implants This is an artificial replacement of tooth root that gives support to a tooth or teeth replaced. The discovery by a Swedish Professor Per-Ingvar Branemaark that titanium (metal) implant can effectively connect with a bone to structurally and functionally perform contributed further to the advancement in the technology of dental implants. Orthopedic Implants These are devices that are fixed in the body to hold bones either due to fracture or its weakness. Devices that are used in this field of medicine to replace a part or all joint is called prosthesis. There are various types of orthopedic implants, which are designed according to the functions of the part of the body being considered. Examples of orthopedic implants are. Hip prosthesis Crania Maxillofacial Implants. Nails, pins, and wires Fragment implants Spine Surgery among others Layered Manufacturing (LM) technology has proved to be the most effective method in manufacture of medical implants this is due to the following factors. Its workability with bio-medical materials such as titanium and silicone The need to manufacture complex shapes associated with biological structures. The ease and speed in manufacture in the event of design of a devise. Uniqueness of biological parts since every being is unique to him or her. (Ramsden1 & Goch, 2007). Reverse and Direct Engineering The outlining of technical aspects of a device through its structural, operational and functional analysis is called reverse engineering. This is very significant in maintenance of a device or in efforts to develop such a device. Reverse engineering for this instance is used in Computer Aided Design (CAD) to create a three dimension model of a real physical part. This is done by analyzing the measurements of an object through scanning For example by use of Laser scanners then making it as a 3D model. The data taken by scanners is represented as point cloud data; that is it is short of topological orientation hence it is represented as a triangular faced mesh, a CAD model or as NURBS (Varady, Martin & Cox, 1997). Point Cloud Data This is three dimensional se of vertices created by 3D scanners which cover large areas on an object and represent it as a point cloud in data file. They are applied in building3D models for the parts to be produced in a manufacturing system, animation, multitude visualization and in metrology. Point cloud is directly applicable in industrial metrology whereby point cloud of a produced part is compared to a Cad model to establish variations which come out as color maps indicating variation in the part and the model (Savio1, De Chiffre & Schmitt, 2007). A polygon is a set of faces while a polygon mesh is a representation of faces edges and vertices in three dimensions that defines a shape. Polygons mesh representing a dolphin. There are various ways of converting point cloud to polygon mesh; they include Delaunary Triangulation Ball pivot algorithm, Marching cubes Marching triangles Processing of Point Cloud Data The best example of the latest program for processing of point cloud data techniques is the VISI it inputs the data on point cloud and polygon mesh from 3D scanners and other devices then transforms it into a simple meshed model. The subprograms in VISI also provides for merging of point cloud data to generate a polygon mesh. Production of a triangulated mesh is automatic in VISI Reverse from the input of the point cloud data into the system. After refining and compensations on the polygon mesh generated it is directed to 3D models like STL OBJ and others. Reconstruction of the polygon mesh model is usually automatic by the VISI Reverse since it acquires all the data on CAD model upon imputing it in STL (VISI Reverse, 2009). NURBS This is an abbreviation of Non Uniform rational B-spline and as used in CAD it is a versatile model used to represent curves and surfaces. Polygon and NURBS Phases These are steps and procedures as discussed earlier, followed in realizing the outcome of reverse engineering when employing the aspects of point cloud or NURBS (Savio1, De Chiffre & Schmitt, 2007). Reverse engineering in automobile and aerospace industries As explained earlier reverse engineering being the analysis of structural functional and operational aspects of a device to enhance its maintenance or development of its kind. It is very applicable in the two industries since parts manufactured have to be very standard for interchangeability in case of need of spare part in maintenance on the other hand different industries may adopt another's design model to enhance its productivity by using reverse engineering technology. It is applied in parts or component design in automobile and aerospace industries by generating already existing parts in CAD models to produce new parts for use in production of new components or repairs. This technology is significant in this aspect since some parts are very complex in geometry and highly valued in the case of aerospace industry. The components mostly produced using these technologies are; the body structure engine systems among others (Vinesh, Kiran & Fernandes, 2008). Conclusion and Future Work Advanced manufacturing technology is increasingly becoming vitally important aspect in functionality of the field of medicine and other disciplines. Some devices used in medical practice cannot be effectively manufactured without employing the methods of advanced manufacturing technology such as layered manufacturing technology and rapid prototyping among others because of their complex geometry and high value. These methods are still being developed and they require high technological skills such as knowledge on CAD and Reverse Engineering among others to implement, this necessitates more ventures in these technologies by manufacturing technologists. In order to fully exploit the benefits of advanced manufacturing technology researchers in this field should venture into seeking to establish more alloys that have good workability with this technology and are bio-medically compatible. References Bidanda, B & Bartolo, J.(2007): Virtual Prototyping & Bio Manufacturing in Medical Applications Derby, B.(2004), Materials Opportunities In Layered Manufacturing Technology. Journal of Material Science. Springer Netherlands. Retrieved on January 25 2010 from http://www.springerlink.com/content/59kahhergby18f7c/ Geng H,(2008) Rapid Prototyping, Tooling, and Manufacturing: Technology overview. Retrieved on January 26 2010 from http://www.globalspec.com/reference/10657/121073/Chapter-5-2-Rapid-Prototyping-Tooling-And-Manufacturing-Technology-Overview .He J, Li D, Lu B (2006) Custom fabrication of a composite hemi knee joint based on rapid prototyping. Rapid Prototype J 12 (4):198-205 Jia Y, Bin Hong-Zan B & Zhang Xiao-Bo (2002) Research on fractal-scanning path for arbitrary boundary layer in Layered Manufacturing, Journal of Shanghai University. Retrieved on January 25 2010 from http://www.springerlink.com/content/xmr3212860432mj8/ Kruth, J. Lieu, M. & Nakagawa, T (1998):Progress in Additive Manufacturing and Rapid Prototyping , Journal Paper. LIOU.F (2007). Rapid Prototyping And Engineering Applications A Toolbox For Prototype Development (Dekker Mechanical Engineering). McLaren, W. (2006). LM Selective Laser Melting-Metals of Nothing. Retrieved on January 26 2010 from http://www.treehugger.com/files/2006/03/slm_selective_l.php Ramsden1, J, & Goch. G (2007): The Design and Manufacture of Biomedical Surface, Journal Paper, ELSEVIER Savio1, E. De Chiffre, L & Schmitt, R (2007): Metrology of freeform shaped parts: Journal Paper, ELSEVIER TWI. Technology Engineering (2008), Selective Laser melting. Retrieved on January 26 2010 from http://www.twi.co.uk/content/laser_slm.html Varady T, Martin R & Cox J (1997):Reverse Engineering of Geometric Models-An Introduction, Computer Aided Design 29 (4), 255-268, 1997 Vinesh R, Kiran J & Fernandes (2008): Reverse Engineering an Industrial Perspective VISI Reverse (2009): Advanced CADCAM Software Solutions For The Manufacturing Industry. Retrieved on January 28 2010 from http://www.vero-software.com/products.phppage_id=1&sub_id=26 Wohlers, T.(2009): Rapid Prototyping/Rapid Tooling: State of Industry. Gardner Publications. Inc. Retrieved on January 28 2010 from http://www.moldmakingtechnology.com/articles/1106additives.html Read More