- Rapid manufacturing - what, why and how?
Foundry Trade Journal (UK), vol. 176, no. 3590, pp. 12,14-15, Apr. 2002
This family of technologies is most widely known as rapid prototyping, however, a plethora of alternative names such as rapid manufacturing, solid freeform fabrication, rapid tooling and layer manufacturing have also been used. One of the main reasons for the variety of terms used is that the original term 'rapid prototyping' implied that layer manufacturing may only be used for producing prototypes. Rapid prototyping processes have been widely used to create tooling, this leading to the term 'rapid tooling'. In 2000 the vast majority of the three million parts produced by layer manufacturing were used for prototyping. However, in the coming years it is likely that layer manufacturing will be used for the manufacture of end use products - so called 'rapid manufacturing'. In the following sections, a number of the main processes are described, along with their applications in the foundry.
- Rapid investment casting of metals
Foundry Trade Journal (UK), vol. 176, no. 3590, pp. 19, Apr. 2002
The vacuum investment casting (VIC) equipment recently used to produce rapid castings from different rapid prototyping (RP) patterns can be divided basically into low temperature (suitable for non-ferrous alloys: Al, Zn, Cu, Mg, etc) and high temperature (suitable for Fe, Ni, Ti, etc alloys) machines. Both type of equipment exists in the Manufacturing Engineering Center (MEC) in Cardiff University. During recent years, the utilisation of the VIC process has expanded rapidly in terms of new practical applications; acceleration of the lead time from CAD design to the real product; utilisation of new alloys.
- High Energy Tomography and Crack Detection
Haase, O; Goebbels, J; Illerhaus, B; Bailey, M; Sene, M
Journal of Nondestructive Testing & Ultrasonics (Germany), vol. 7, no. 2, Electronic format, Feb. 2002
The characterisation and evaluation of large and/or high density objects with X-ray computed tomography (CT) requires high energy X-ray sources especially electron linear accelerators (LINAC) with energies between 2 and 12 MeV. The decrease of linear attenuation coefficient with increasing energy reduces the necessary dynamic range of detector system as well as the number of artifacts both belonging to the main problems in CT today. Actually the following applications are well suited for using high energy tomography: geometrical analysis of complex parts for rapid prototyping (e.g. cylinder heads, CAD, FEM, Stereolithography), structure evaluation and detection of defects (e.g. tires), and characterisation of waste containers (e.g. HLW canisters, crack evaluation). The last mentioned application were discussed together with some details of the developed detector and collimator system. A full set of tomographic images of a glass block were measured and together with the planned leach testing experiments which should confirm the values for the accessible surface area a non-destructive method to characterize HLW glass blocks is expected.
- Cost-effective solid reconstruction from an X-ray image
Shum, SSP; Lau, WS; Yuen, MMF; Yu, KM
Journal of Materials Processing Technology (Netherlands), vol. 121, no. 2-3, pp. 207-216, 28 Feb. 2002
Solid reconstruction of a 3D computer solid model from 2D line drawings has been studied widely over the last two decades. In fact, it is one critical operation in the rapid reverse engineering of a mechanical part. The computer model reconstructed can be used in down-stream operations such as part re-design, engineering analysis, rapid prototyping or CAM. For industrial application, the method should be efficient, cost effective, with minimum human interaction, and reasonably accurate. A new method is studied and implemented using a computer-vision approach to extract information from a mechanical part and generate the corresponding computer model. The method takes advantage of X-rays to capture images of an object with obscured interior details. The reconstruction algorithm will generate an information-complete solid model. The paper explains and discusses the method with examples and explores its cost effectiveness. Materials used: steel and aluminum.
- Alternative materials for rapid tooling
King, D; Tansey, T
Journal of Materials Processing Technology (Netherlands), vol. 121, no. 2-3, pp. 313-317, 28 Feb. 2002
Rapid tooling is an extension of rapid prototyping technology. Rapid prototyping techniques are capable of producing prototypes of very complex part geometry directly from three-dimensional CAD software in a wide variety of materials such as polymer, wax, and paper without the benefit of specially designed tooling or fixturing. Rapid tooling is enabling art to production of quality parts and accelerating time to market by concentrating on the tool rather than the part. The selective laser sintering (SLS) rapid prototyping process has been adapted to produce metal-based prototypes that can be used in rapid tooling applications. The SLS process fuses, or sinters, the powder to form the mould geometry, which is then filled with bronze to form a metal matrix. This is a very recent development so there is some uncertainty associated with it. Modular injection mould tool inserts will be constructed with the view to greatly reduce the time to market allowing the use of alternative tool materials (i.e., RapidSteel, copper polyamide and CNC machined Ureol and Araldite). An investigation will be conducted to establish the process from the CAD data to the final product. These tools will also undergo numerous tests to confirm design accuracy for form, fit and function testing, turnaround times, and for marketing evaluation. This paper will discuss the outcome of my research for the selection of the most appropriate mould material where time to market is of critical importance.
- Finite element analysis of single layer forming on metallic powder bed in rapid prototyping by selective laser processing
Matsumoto, M; Shiomi, M; Osakada, K; Abe, F
International Journal of Machine Tools & Manufacture (UK), vol. 42, no. 1, pp. 61-67, Jan. 2002
A method for calculating the distribution of temperature and stress within a single metallic layer formed on the powder bed in rapid prototyping with the selective laser melting method is proposed. The solidified layer is assumed to be subjected to plane-stress deformation and the two-dimensional finite element methods for heat conduction and elastic deformation are combined. In the simulation, the finite element mesh is constructed on the surface of the powder bed. The heat caused by laser irradiation is given to the elements under the laser beam. Shrinkage due to solidification is assumed to result in only the change of the layer thickness. In the elastic finite element simulation, the Young's modulus of the solidified part is expressed as a function of temperature. To simplify the calculation, the whole area is treated to be continuous, and the powder bed and the molten part are assumed to have a very small Young's modulus. The heat conduction and the elastic finite element calculations are carried out alternately. The obtained results of deformation and tensile stress distribution show the possibility and places of cracking of the layer during forming. (Example material: nickel alloy.)
- Rapid prototyping
Foundry Management and Technology (USA), vol. 130, no. 1, pp. 92-93, Jan. 2002
Successfully launching a casting into the market depends on fast, efficient product development, coupled with quick and flexible manufacturing processes. For automotive companies, aerospace parts producers, and consumer product manufacturers, speed-to-market is essential. Metalcasting processes can be the most effective methods for producing metal parts in terms of material use and labor cost. However, the long lead-time between purchasing and product approval can offset these advantages: a result of the need for a pattern to create the mold. The pattern design process often requires iterative trial-and-error prototyping since gating design, usually described as an art, is often based on empirical, mostly undocumented, experience.
- Characterization, oxidation and sulphidation resistance of UNS7718 superalloy fabricated by laserforming process
Mahapatra, SK; Khanna, AS; Gasser, A
NACE International, Corrosion/2002 (USA), pp. 10, 2002
Laser forming is a direct metal deposition process that combines high power laser alloying technology with the advanced methodology of rapid prototyping to manufacture complex three-dimensional geometries directly. The present study involves the use of this technique to form nickelbased-superalloys in simple geometry to compare their characteristics with the conventional alloys. The superalloys used in this study are Alloy 718. The characterisation of the formed alloys comprised of a complete microstructural analysis, oxidation and sulphidation behaviour. The preliminary results obtained so far indicate re-orientation of gamma ' and gamma " precipitates, change in local composition and marginal improvement in oxidation behaviour.
- Manufacture of the die of an automobile deck part based on rapid prototyping and rapid tooling technology
Song, Y; Yan, Y; Zhang, R; Xu, D; Wang, F
Journal of Materials Processing Technology (Netherlands), vol. 120, no. 1-3, pp. 237-242, 15 Jan. 2002
To produce the metal die of an automobile deck part of high quality at low cost with a short cycle, a new method of manufacturing the die, based on rapid prototyping and rapid tooling, is proposed in this paper. First, the technological process of rapid processing (RP) technology and the large-scale rapid processing and manufacture (RP and M) equipment SSM-1600 that is based on the innovative idea of concurrent processing in a divided field are introduced. The SSM-1600 equipment supplies a gap in the field of making large prototypes. The technology of the unbaked ceramic mold casting process based on RP technology is also introduced. The method of 3D non-linear coupled thermo-mechanical FEM analysis is adopted to analyze the dimensional accuracy of the die of an automobile deck part during the casting solidification process. The simulation result can be used to modify the CAD model to further improve the precision of the die. The system of manufacturing the die of an automobile deck part based on rapid prototyping has gained success by the verification of practical production.
- Patternless casting molding technic and process research
Zhai, L; Xu, D; Lu, Q; Yan, Y
Zhuzao Jishu (Foundry Technology) (China) (China), vol. 23, pp. 37-39, Jan.-Feb. 2002
The patternless casting molding, a new rapid prototyping technology, is introduced and its forming process is researched. In order to reduce the content of resin in sand mold, the selective-filling molding method is put forward and applied in the experiment of mold making. The casting test proves that the casting molded made by this method can meet the casting technical requirements.
- Rapid manufacturing of metal die for shoot-squeeze molding (DISA) system
Mei, Q; Wu, Z; Ye, S; Deng, Q
Tezhong Zuzao Ji Youse Hejin (Special Casting & Nonferrous Alloys) (China) (China), pp. 10-11, Jan.-Feb. 2002
The rapid manufacturing process of the die for housing castings in DISA cast line was introduced. Based on 3D modeling and rapid prototyping in combination with coating transferring investment casting technology, the iron die was made. The manufacturing process has the advantages of high rate, low cost and high die precision and is suitable for wide application in making the metal die of DISA cast line. HT250 is used as the raw material for manufacturing the metal die of DISA system.
- EDM performance of TiC/copper-based sintered electrodes
Li, L; Wong, YS; Fuh, JYH; Lu, L
Butterworth-Heinemann Ltd., Materials and Design (UK), vol. 22, no. 8, pp. 669-678, Dec. 2001
This paper presents a study of the effect of titanium carbide (TiC) on the performance of sintered copper-based materials as electrical discharge machining (EDM) electrodes. The aim of this study was to provide a preliminary evaluation of EDM electrodes fabricated by laser-based sintering using rapid prototyping technology (RP). Six batches of titanium carbide with content from 5% to 45% were fabricated by mixing, ball milling, pressing, and liquid phase sintering with copper-tungsten (Cu-W) and copper (Cu), respectively. The performance of the newly formed material is compared with commercial electrodes. The densification of TiC /Cu-W system was improved by the addition of nickel (Ni), as Ni shows good solubility in both Cu and W. The distribution of particle size becomes narrow as the proportion of TiC is increased. A uniform dispersion of small TiC particles in the Cu-W system and a narrow particle size distribution provide the possibility of obtaining dense electrodes. With increasing TiC, the relative density first increased and then decreased, whereas the electrical resistivity first decreased and then increased. EDM electrodes, with the addition of TiC, show good performance in surface finishing. This is an important characteristic as RP-sintered EDM electrodes are expected to be used as finishing electrodes. The surface roughness of most specimens is less than those machined using commercial electrodes. Electrodes with 15% TiC show the highest relative density, lowest electrical resistivity, and good EDM performance, i.e. lowest tool wear ratio (TWR) and highest material removal rate (MRR) at low current, and the best surface finish not only at low current, but also at high current. (Steel workpiece.)
- Evaluation of inserts for modular thermoplastic injection moulds produced by spin casting
Gatto, A; Iuliano, L
Journal of Materials Processing Technology (Netherlands), vol. 118, no. 1-3, pp. 411-416, 3 Dec. 2001
Concurrent engineering enables a company to speed up its time to market: rapid prototyping forms a part of this approach. The term rapid tooling (RT) refers to the rapid creation of tools in much the same way as RP means the rapid creation of models. It is a method that offers both designers and manufacturers attractive advantages in the form of time compression and cost reduction. In an era of automated manufacturing the prototype can be produced layer by layer directly from a 3D CAD model using rapid prototyping (RP) techniques [Rapid prototyping and manufacturing, fundamental of stereolithography, SME, Dearborn, MI, 1992; Layer Manufacturing a Challenge of the Future, Tapir Publisher, Trondheim, Norway, 1992]. The drawback is that only a limited number of RP technologies cater for metal parts and taking the top three positions of vendors into account (Stratasys, 3D Systems, Sanders), their systems have no access to metal prototypes [Rapid prototyping, state of the industry report 1998, SME, Dearborn, MI, 1999]. Several RT techniques can be employed to save time in the manufacturing of plastic injection moulds: thermal spraying; quick casting, electroplating, direct metal sintering. These techniques have been subject to intensive study for a number of years and their extensive commercial potential makes them attractive propositions. Major advances in technology makes spin casting a fully proven tool for manufacturing and prototyping functional components. This paper describes the employment of spin casting for the construction of mould inserts in standard, commercial-grade pressure die casting zinc.
- Critical parameters influencing the quality of prototypes in fused deposition modelling
Anitha, R; Arunachalam, S; Radhakrishnan, P
Journal of Materials Processing Technology (Netherlands), vol. 118, no. 1-3, pp. 385-388, 3 Dec. 2001
Rapid prototyping (RP) meets the current needs in the industry to shorten design cycles and improve the design quality. Fused deposition modelling (FDM) is one of the key technologies of RP. Various process parameters used in FDM affect the quality of the prototype. Work was undertaken to assess the influence of the parameters on the quality characteristics of the prototypes using Taguchi technique. This paper discusses the results of the study and the conclusions arrived from it.
- Casting of titanium and its alloys
Journal of Japan Foundry Engineering (Japan), vol. 73, no. 12, pp. 784-790, Dec. 2001
Diagrams compare the 1999 year percentage of titanium use in sheet metal forms in US and Japanese industries. In US, 50% of produced Ti and its alloys are used in commercial aircraft while in Japan, 53% is used in exported goods. An attractive feature of titanium castings is certainly their small size. In the paper a diagram gives the tonnage export of 11 categories of products made form titanium and exported between 1991 and year 2000. For large scale castings of Ti and Ti alloys today; the consumable electrode technique is widely used in which large amounts of currents is passed through the casting and an electrode made of same alloy to generate electric arc and melt the combination. In the Levitation melting technique as per illustration, the metal molten pool is levitated by magnetic forces within ceramics mold cavities. Photographs of golf clubs made by such technique are shown. Through use of stereo lithography and rapid prototyping technology the application of titanium and titanium alloy castings are becoming more practical in recent years. (Materials noted: Ti-6Al-4V, Ti-1100, IMI-834.)
- A brief history of rapid prototyping and manufacturing: the growth years
P/M Science & Technology Briefs (USA), vol. 3, no. 5, pp. 13-16, Nov. 2001
This article is the second of a trilogy. The first, entitled 'A Brief History of Rapid Prototyping and Manufacturing: The Early Years' appeared in P/M Science and Technology Briefs, Vol. 3, No. 2, April 2001. That article focussed on the birth of RP and M, with special emphasis on its relevance to powder metallurgy. The so-called 'early years', from 1986 through 1992, were dominated by the invention, development, and subsequent advances in stereolithography. Appropriately, the first article of this trilogy focused on this revolutionary technology. This article will concentrate on 'the growth years', from 1991 through 1996. This period was marked by almost 50% annual expansion in the number of RP and M systems used worldwide, the birth of competing technologies, and the gradual awakening of a wider audience to the many advantages afforded by RP and M. This article will describe some of the alternative RP and M systems, with special emphasis on their increased use of powder metallurgy based techniques.
- Rapid manufacturing from integrating rapid prototyping and casting process
Liang, J; Shan, Z; Zhang, R; Yan, Y
Zhuzao Jishu (Foundry Technology) (China) (China), pp. 29-32, Nov.-Dec. 2001
This paper introduces the integrated rapid manufacturing processes which combine rapid prototyping with casting process. Parts or tools with high quality can be fabricated at low cost and fast speed to meet the market demand. The applications of rapid prototyping technology are analyzed in the field of foundry by case study.
- The progresses in formability of materials in rapid prototyping and manufacturing technique
Shen, Y; Chen, W; Zhao, J; Yu, C; Tan, Y; Liu, F
Cailiao Kexue yu Gongcheng (Materials Science and Engineering) (China) (China), vol. 19, pp. 90-96, Oct.-Dec. 2001
Fundamentals and characteristics of several typical rapid prototyping and manufacturing (RP&M) techniques are introduced. Furthermore, the latest study and application of materials for RP&M technology are described, and the formability problems of materials in RP&M are discussed. Developing materials for RP&M technology and researching the formability of the materials are important research directions.
- Enormous growth potential for rapid prototyping
Giesel Verlag fur Publizitat GmbH, Aluminium (Germany), vol. 77, no. 9, pp. 669-670, Sept. 2001
The company Weihbrecht Lasertechnik in Wolpertshausen sees enormous potential for growth in the area of rapid prototyping. At CasTec the firm presented Information about its extensive services in this sector. It has a universal 'Speedvac' unit that enables metallic prototypes to be made by precision casting in only a few days, from 3D data files up to the ready cast metal article. Here, the maximum possible component dimensions are 300 x 300 x 300 mm and wall thicknesses can even be less than 1 mm. Casting of the light metals aluminium and magnesium is possible. The structure is virtually pore-free and is similar to that produced by pressure diecasting, so that maximum comparability with a component to be mass produced later is ensured.
- Influence of heat treatment upon SLS processed composites fabricated with alumina and monoclinic HBO sub 2
Journal of Materials Science Letters (USA), vol. 21, no. 3, pp. 209-212, 1 Feb. 2002
Selective laser sintering (SLS) is a form of the rapid prototyping technology which produces geometrical objects directly from a three-dimensional computer image without part-specific tooling or human intervention. These rapid prototyping techniques have recently been developed to overcome some of the barriers of conventional manufacturing techniques, such as difficulties in tooling complex-shaped ceramic parts and long production time in fabricating prototypes. The computer image is generated using CAD /CAE software or a computer imaging process. The three-dimensional computer image is numerically sliced into a series of two-dimensional cross-sections. The SLS machine regenerates these two-dimensional patterns on the powder bed by selectively scanning the powder bed with a focused laser beam and binding the loose powder. The thickness of the sintered powder layer is generally 125-250 mu m. The sintered layer is lowered from the sintering plane and a new layer of the powder is spread again. The laser scans again, resulting in sintering of the powder particles, and bonding the present layer to the underlying previous layer. The desired object is generated by laying down a number of such layers and successively sintering them. The primary advantage of SLS process is the flexibility of selection of material systems compared to other SFF techniques. High purity alumina (melting point 2050 deg C) was chosen as a high melting component since it is one of the most widely used advanced ceramics and is relatively low in cost in comparison to other high temperature ceramic materials. Boron oxide (melting point 450 deg C) was selected as a starting low melting phase.
- Rapid prototyping - future for bioceramic implants
Materials Technology (UK) (UK), vol. 16, no. 3, pp. 177-179, Sept. 2001
From the top of the head to the bottom of the feet, it has become increasingly possible to use 'engineered' parts to correct medical problems that the human body cannot fix. Through a combination of rapid prototyping, advanced software, and state-of-the-art materials processing, Javelin, a Utah-based design firm, has pioneered a process to directly create mimetic bone biostructures. Javelin has used their process, MedLAM to demonstrate the direct fabrication of wrist, inner ear, and facial bones from patient-supplied Computed Tomography (CT) data. The process has been used to demonstrate bone biostructures out of alumina, zirconia, and phosphate-based bioceramic materials.
- Rapid tooling approaches for small lot production of sheet-metal parts
Muller, H; Sladojevic, J
Journal of Materials Processing Technology (Netherlands), vol. 115, no. 1, pp. 97-103, 22 Aug. 2001
Using Rapid Prototyping Techniques (RPTs) like Stereolithography or Selective Laser Sintering, the automotive industry produces plastic parts for prototypes faster and cheaper compared to the techniques used up to now. As a consequence of this process, the automotive industry increasingly demands to have sheet-metal parts also earlier than now at their disposal. This paper deals with rapid prototyping (RP) process chains to manufacture large sheet-metal forming tools. It gives an overview of technically possible solutions. After that, the paper deals more in detail with two of the approaches, namely layer milling and resin casting. It describes these manufacturing methods and presents the result of a case study which compares the approaches with the actually used production method. Materials mentioned for tools: Zamak(zinc base alloy), bismuth-tin alloy and polymer resin.
- Rapid prototyping technique for fabricating ceramics
Zhang, J; Han, J; He, X; Du, S
Cailiao Gongcheng (Journal of Materials Engineering) (China) (China), pp. 37-40, June 2001
Principle, process and characteristics of rapid prototyping (RP) techniques used for fabricating sophisticated ceramic objects, such as laminated objected manufacturing (LOM), fused deposition modeling (FDM), shape deposition modeling (SDM), stereo-lithography (SLA), selective laser sintering (SLS) and ink jet method (IJM), are reviewed. The results show that the RP has the potential to fabricate sophisticated ceramic objects, such as structural ceramics, functional ceramics, biological ceramics and piezoelectrical ceramics. The quality of RP ceramics is compared well with that of conventionally processed ceramics.
- Determination of fabricating orientation and packing in SLS process
Hur, S-M; Choi, K-H; Lee, S-H; Chang, P-K
Journal of Materials Processing Technology (Netherlands), vol. 112, no. 2-3, pp. 236-243, 25 May 2001
Rapid prototyping (RP) technology has been implemented in all industries needed to reduce the time for the development of new products. An orientation and packing in RP process, especially selective laser sintering (SLS), are considered as the most important factors to maximize the utilization of space in the build vat and reduce build time. However, the decision of these parameters is mainly dependent on the skill level and experience of the SLS machine operator. This paper addresses the methodology to find the optimal build layout, by considering an orientation and packing of multiple parts in SLS processing. For the optimal orientation, the fabricating height and the feeding powder quantity to reduce build time and the surface quality improvement of prototypes is considered as major objectives. In packing process, each prototype to be fabricated is modeled as a voxel structure to deal with the inefficiency of a bounding box approach. The developed orientation and packing system employs the adapted bottom-left(BL) approach with a genetic algorithm(GA) and is demonstrated in real prototypes for processing with SLS and illustrates a good enabling optimization building system to the real industries.
- Shrinkage effects in photopolymerizable resin containing polymer filler for SL
Duan, Y; Wang, S; Li, D; Fan, X; Lu, B
Cailiao Kexue yu Gongcheng (Materials Science and Engineering) (China) (China), vol. 19, pp. 39-42, Apr.-June 2001
The influence of polymer filler on the shrinkage of photocurable resin used for stereolithography (SL) is studied by measuring the viscosity, the specific gravity, the photocuring speed, the linear shrinkage and the volume shrinkage of the resin containing polymer filler. The resin containing polymer filler is tested on the laser rapid prototyping manufacturing system, and the result indicates that the resin containing polymer filler can reduce the shrinkage of the photocurable resin used for stereolithography.
- Strength analysis of mold shell manufactured with selective laser sintering technology
Zhao, J; Zhang, J; Yu, C; Huang, Y; Zhang, Y; Yu, X
Journal of Nanjing University of Aeronautics & Astronautics (China), vol. 33, no. 1, pp. 41-45, Feb. 2001
Polymer coated ceramic powder can be used to manufacture mold shell with selective laser sintering technology, and the mold shell is usually used to cast and produce metal part. Usually, the laser energy used in rapid prototyping manufacturing is not beyond 100 W. It is not enough to sinter ceramic powder directly. So indirect-sintering is adopted. But, the wear intensity of mold shell, which is determined by some sintering parameters, is a fatal reason to cast unsuccessfully. Generally, post-processing, such as high temperature sintering, is unavoidable for those wear intensity shell. This paper presents some results which show the effect of scan speed and scan space on shell intensity, describes the post-processing, and discusses its application to SLS mold shell. Results gained from this process show that it is obvious to improve the intensity of mold shell. An example is used to validate these results above.
- Rapid precision casting for complicated thin-walled aluminium-alloy parts
Dong, XP; Huang, N; Fan, Z; Wu, S; Liu, H
Indian Foundry Journal (India), 47, (8), 17-22, Aug. 2001
Based on Vacuum Differential Pressure Casting (VDPC) precision forming technology and the Selective Laser Sintering (SLS) Rapid Prototyping (RP) technology, a computer based rapid manufacturing metallic parts method called Rapid Precision Casting (RPC) process has been investigated. The experimental results showed that the main advantage of RPC is not only its ability to impart higher internal quality and accuracy to complicated thin-walled Al-alloy metallic parts, but also shorten the time cycle of production greatly compared to SLS plastic prototyping to metallic parts. The key parameters of forming technology of RPC for complicated thin-walled metallic parts for developing new production and method and tooling were settled, established. It has been shown that it is possible to rapidly manufacture high quality and accuracy metallic parts by means of RP in foundry industry. Materials used: ZL101 aluminum alloy.
- Characterization of laser-deposited TiAl alloys
Zhang, XD; Brice, C; Mahaffey, DW; Zhang, H; Schwendner, K; Evans, DJ; Fraser, HL
Scripta Materialia (USA), 44, (10), 2419-2424, 25 May 2001
Laser Engineered Net Shaping (LENS) is a direct laser deposition technique. Combining laser cladding technologies with advanced rapid prototyping methods, LENS has a capability to manufacture fully dense, complex three-dimensional components directly from a computer model of an object without part-specific tooling. A continuous wave (CW) Nd:YAG laser has been used in the present study. In addition to the processing advantages in net shape, containerless melting (solid freeform) and dramatically shortened development cycle times for engineering systems, LENS processing can also offer fine, rapidly solidified microstructures (cooling rates up to 10 exp 6 Ks exp -1 ). Materials processed in this way experience small heat-affected zones, which will have significant potential for further improvements in properties relative to cast and wrought materials. In this paper, recent results are presented involving the microstructural characterization of TiAl intermetallics produced by LENS, with the aim of better understanding the effect of LENS processing on the microstructure, and ultimately on the mechanical properties, of the deposited materials. Comparison of microstructures produced by LENS and conventional processing techniques will also be given in the paper.
- Rapid prototyping of a headlight with sheet metal
Jeswiet, J; Hagan, E
Materials in the Automotive Industry: Proceedings of the International Symposium on Materials in the Automotive Industry as held at the 40th Annual Conference of Metallurgists of CIM (COM 2001), Canadian Institute of Mining, Metallurgy and Petroleum, 109-114, 2001
It will be shown how incremental forming can be used as a rapid prototyping method with sheet metal. An actual example is given, in which the reflective surface for the headlight of a 2004 vehicle is rapid prototyped. This type of reflective surface provides the ultimate challenge to incremental forming because it requires the reproduction of surfaces which have complicated fourth order polynomial shapes which must intersect seamlessly without causing any perturbation to the reflection of light in the cavity. The two critical parameters for a reflective surface are penetration, in candelas, and dispersion in percentage. In this case, the incrementally formed aluminum sheet, once aluminized, produces a light penetration that is better than the specification. This paper will describe the results. (Materials used: 3003 aluminum or copper roofing.)
- Using numerical simulation with rapid prototyping and investment casting
Wu, M; Schadlich-Stubenrauch, J; Wanger, I; Sahm, PR
JOM (USA), 52, (8), 45-47, Aug. 2000
This article presents an approach to making an aluminum automobile prototype by integrating numerical simulation and rapid prototyping into investment casting. Following the integrated prototype procedure, a sound aluminum (Al-Si-7Mg) manifold prototype with excellent contour and an acceptable surface finish was made with only one casting trial. This study indicated that the potential of the rapid prototyping-investment casting coupling could be more effective with the aid of integrated numerical simulation, and numerical optimization of the casting parameters aids in minimizing the risk of casting failure and avoiding the iterative casting trials.
- Padding, welding and freeform fabrication of nickel aluminide intermetallic compound by reactive rapid prototyping process
Matsuura, K; Koyanagi, T; Kudoh, M; Oh, JH; Kirihara, S; Miyamoto, Y
Materials Transactions (Japan), vol. 43, no. 5, pp. 1146-1152, May 2002
A novel method for padding, welding and freeform fabrication of intermetallic alloys based on an exothermic synthesis reaction between powder and droplets is proposed, and its feasibility is examined using nickel monoaluminide, NiAl, as a demonstration material. In an experiment for NiAl padding on steel, a small amount of nickel powder was fed onto a steel surface, followed by supplying an aluminum droplet onto the powder. The nickel and aluminum exothermically reacted and produced a NiAl bead on the steel surface, bringing about strong bonding between the NiAl bead and the steel. In an experiment for welding of NiAl, when an aluminum droplet was dropped onto nickel powder fed into a root gap between two NiAl base metals, they exothermically reacted and produced a molten NiAl bead. The heat from the reaction melted the base metals near the interface with the molten NiAl bead. After solidification of the molten NiAl bead and the melted parts of the base metals, welding of the base metals was completed. In an experiment for freeform fabrication of NiAl, when an aluminum droplet was dropped onto a nickel powder bed, the two metals reacted and produced a small NiAl bead. When a next droplet was fallen to a position very close to the NiAl bead, a new NiAl bead was similarly produced and was bonded to the former one. By continuous dropping of aluminum droplets a two-dimensional structure of the NiAl beads was configurated. After the two-dimensional structure was finished, nickel powder was added until it wholly covered the structure on the former plane, and then a new structure was similarly configured in the added nickel powder bed. The NiAl beads were bonded to each other in both horizontal and vertical directions. Finally, a three-dimensional structure was finished after repeating the addition of the powder and the supply of the droplet.
- Use of LOM rapid prototyping in metal founding
Indian Foundry Journal (India), vol. 48, no. 4, pp. 41, Apr. 2002
Laminated Object Manufacturing (LOM) is a rapid prototyping process that offers an alternative for the rapid and cost-effective production of patterns, particularly for milling, and is suitable for the production of metal castings in sand moulds. The sticking together of cut-out pieces of special paper one on top of the other builds up 3-dimensional patterns in layers. The earlier problem of the subsequent growth of the pattern in the z-axis has been overcome by the development of a new type of paper which was initiated by Invenio GmbH and implemented by a well-known paper manufacturer. The paper layers are no longer stuck together over the whole surface but at points. The resulting spaces between the points are then infiltrated with a resin. In addition to the hygroscopic effect in the edge region of the component a vacuum is applied. The resin penetrates into the component to a standard depth of 2 mm. If required greater depths are possible, up to complete impregnation. According to the component geometry it is possible to realize dimensionally and geometrically stable patterns with wall thicknesses from 2 mm upwards. The basic accuracy of the components is within the middle tolerance class specified in DIN ISO 2768. According to requirements it is possible to achieve dimensional tolerances down to plus/minus 0.2 mm in the x an y directions. Variations of 0.5% can occur in the z-axis.
- Corrosion-resistant casting alloys
Spence, TC; Stickle, DR
Advanced Materials & Processes (USA), vol. 160, no. 1, pp. 51-54, Jan. 2002
Many significant strides have been made over the past quarter century in developing new corrosion-resistant casting alloys such as the super austenitics and super duplex stainless steels, but it is unlikely that such breakthroughs will continue in the future. This article discusses the five factors that are critical to production of corrosion-resistant castings; issues important to the development of cast alloys from wrought compositions; and technologies that speed casting development, including rapid prototyping and solidification modeling. (Sample materials include nickel, Alloy 20, CD4MCuN, and various other Ni-Cr-Mo alloys.)
- Rapid prototyping of 5356-aluminum alloy based on variable polarity gas tungsten arc welding: process control and microstructure
Ouyang, JH; Wang, H; Kovacevic, R
Materials and Manufacturing Processes (USA), vol. 17, no. 1, pp. 103-124, Jan. 2002
This paper concentrates on rapid prototyping of a 5356-aluminum alloy based on a new deposition process of variable polarity gas tungsten are welding (VPGTAW), and describes the microstructure and geometrical properties of the deposited layers. The wettability and distortion tendency of the deposited layers is effectively improved by preheating the substrate up to 118 deg C, monitoring the arc-length, and adjusting the arc current during the deposition process. The relationships between the geometry of the deposited layers and the welding parameters are developed. The surface roughness of the deposited parts is found to be in the order of 2 mu m. The deposited layers exhibit equiaxed dendrites at the top layer, fine equiaxed grains at the middle, and bottom of a deposited wall together with some precipitates distributed at the grain boundary regions, and coarse columnar grains at the bonding zone between the deposited wall and the substrate. The residual microstructure such as grain size and distribution of precipitates is highly dependent on the related locations in the deposited wall. The deposited samples possess a maximum hardness at the top layer and exhibit a slight decreasing trend towards the middle and bottom of the fabricated part due to the heat effects of the material that occurs during the deposition. By understanding these relationships between parameters and their effect on the process output, the process can be used more effectively and the quality can be improved as well.
- Micro rapid prototyping
Metal Industries (China) (Taiwan), vol. 36, no. 4, pp. 59-61, 2002
Introduced Micro Rapid Prototyping technologies in this article are Micro Stereolithography and Micro Stere-Photolithography. Materials involved: metals, polymers and ceramics.
- Real-time molten pool area extraction for control of gas tungsten arc welding
Wang, YZ; Jandric, Z; Kovacevic, R
National Institute of Standards Technology, Eleventh International Conference on Computer Technology in Welding (USA), pp. 87-94, 2002
This paper presents a real-time molten pool area extraction method for the control of gas tungsten arc welding (GTAW) with a wire filler in the hybrid rapid prototyping and tooling (RP and T) technique based on welding and CNC milling. The molten pool shape and size were strongly influenced by the two-dimensional geometry of the built part. A coaxial machine vision unit is used to acquire images of molten pool and its surrounding area through the torch. After image processing, the boundary of the molten pool is extracted. Because the molten pool is partially hidden by the tungsten electrode, its boundary is incomplete. The molten pool area is selected as the feedback to the closed-loop control of the GTAW process. In order to calculate the area of the molten pool with an incomplete boundary, a neural network is used. By changing welding parameters, the neural network is trained for different sizes of molten pools. The testing of the neural network is performed by another group of molten pool images.
- Fabrication of patterns in the sand foundry without models
Giesserei-Praxis (Germany), vol. 11, pp. 439-441, Nov. 2001
ACTech has developed and patented a rapid prototyping method for producing a sand pattern with a model. Using 3D-CAD data, complex castings can be produced very rapidly in sand casting quality. The technology, especially the direct milling of the form material, is especially suitable for larger casting segments.
New proportions during laser sintering for efficient casting production
Giesserei-Praxis (Germany), vol. 11, pp. 442-444, Nov. 2001
Laser sintering technology has widely established itself as rapid-prototyping method for accelerating and efficient designing of development processes. It is now not only a tool for production development but also is increasingly considered as a production tool for the manufacture of limited quantities. New developments include a new material for optimum component quality with a faster throughput, new software for greater flexibility and accuracy during CAD data processing as well as new hardware and process software features that further increase productivity and user friendliness.
- Prototype parts in magnesium alloys by express casting
Defouloy, D; Monnier, L
Hommes et Fonderie (France), vol. 318, pp. 12-15, Nov. 2001
The important progress in innovative technologies, associating laser techniques, computers and electronics, added with the 3D-scanning of pieces answer the 3 current fundamental features: cost reduction, significant diminution of the delivery time, general increase of the quality. The rapid prototyping associated to the express foundry allow a rising range of parts that could be cast in sand moulds or by investment casting, for instance with thin wall thickness, while staying rigorously inside the usual strain: cost-delivery time-quality! Obtaining models in lost materials by laser sintering or obtaining direct sand cores or obtaining resin stereolithography models which allow manufacturing of low conception moulds for wax injection or even obtaining wax models directly by deposition-extrusion allow a production of prototype parts corresponding entirely to the current expressed needs. So it is the entire chain skil (CAD/RP/express casting) that allows those evolutions.
- Current rapid tooling technologies
Diecasting World (UK), vol. 175, pp. 16-17, Sept. 2001
Two methods of rapidly making casting dies are described, namely steel laminate manufacture and direct metal laser sintering. These methods are at the stage where they are emerging from the laboratory and into pilot scale production in commercial diecasting shops. This article is intended to make diecasters aware of these new weapons in the industry's manufacturing armoury.
- DMLS moves from rapid tooling to rapid manufacturing
Metal Powder Report (UK), vol. 56, no. 9, pp. 24, 26-29, Sept. 2001
The Direct Metal Laser Sintering (DMLS) process from EOS is well established for the netshape fabrication of prototype and short series tooling for plastic injection moulding and diecasting. Now, recent developments in the powders coupled with the durability of the materials are extending its reach to the direct manufacturing of functional prototypes for powder metallurgical (PM) and cast components - in the following referred to as rapid manufacturing - as well as tooling for powder injection moulding and other applications. This article reviews the development of DMLS and its current and potential applications.
- Annual review of molding sands. Part 2. Molding processes with non-clay bonded molding sands; coatings; full mold casting processes. (38th continuation)
Giesserei (Germany), vol. 88, no. 9, pp. 60, 62, 65-66, 69-70, 72, 75, 11 Sept. 2001
A literature review covering process summaries and comparisons, process with inorganic and organic binders, miscellaneous processes, coatings, core sand regeneration full mold casting method and rapid prototyping.
- Rapid tool making in the service of concurrent engineering
Vasconcelos, P; Lino, FJ; Neto, RJ
Tecnometal (Portugal), vol. 23, no. 136, pp. 17-21, Sept.-Oct. 2001
Rapid prototyping (RP) and direct rapid tooling (DRT) technologies have reduced the time to design manufacture of metal castings and plastic moldings. Mathematical modeling of the structures and manufacturing processes has provided an important technique to the practice of concurrent engineering. Various RP and DRT technologies lend themselves to integration with 3D CAD and CAM systems. Brief explanations of various DRT techniques such as direct AIM tooling, SLS, DMLS, and DSPC are given along with indirect RT techniques for making prototypes in silicone, plastic and metal molds.
- Reaping RP's benefits
Foundry Management and Technology (USA), vol. 129, no. 7, pp. 20-24, July 2001
Making its metalcasting debut nearly 10 years ago, rapid prototyping (RP) technology has become at once both commonplace and revolutionary. Commonplace, in that more and more foundries are regularly integrating the technology into their production schedules. Revolutionary in that as RP becomes more and more refined, its possible uses grow exponentially. The question becomes then, how can metalcasters blend both the mundane and the revolutionary aspects of this technology to make sure they're getting the most out of it.
- Stainless steel part by laser rapid prototyping
Xi, M; Zhang, Y; Zhang, P; Shi, L; Cheng, J
Tezhong Zuzao Ji Youse Hejin (Special Casting & Nonferrous Alloys) (China) (China), pp. 19-20, July-Aug. 2001
The thin-walled 316L stainless steel parts were prepared by the laser rapid prototyping. The results show that the shaped parts with compact microstructure is characterized by the dendrite formation and the uniformly distributed chemical composition. And the mechanical properties of the thin-walled metal parts by laser rapid prototyping are comparable to those of the conventionally machined metal parts.
- Rapid tooling method using Plasma Transferred Arc
Hayashi, C; Shinoda, T; Kato, Y
Denki Seiko (Electric Furnace Steel) (Japan), vol. 72, no. 3, pp. 147-154, July 2001
Directed Plasma Fabrication (DPF) is a rapid tooling process that is based on the controlled deposition of molten metal particles according to computer-controlled patterns. It makes fully dense, near net shape metallic components without casting, pressing or forging processes in molds or dies. Experimental works were carried out using a conventional low current Plasma Transferred Arc welding system, and the atomized Stellite #21 powder. Cylindrical shapes are successfully deposited into the wall 2.5-4.2 mm thick. The key factor is the non-dimensional "operating parameter n" which, was proposed by Christensen. The better deposition efficiency is obtained with the shorter arc length and the slower traveling speed under the same plasma current.
- Rapid hard tooling by plasma spraying for injection molding and sheet metal forming
Zhang, H; Wang, G; Luo, Y; Nakaga, T
Thin Solid Films (Switzerland), vol. 390, no. 1-2, pp. 7-12, 30 June 2001
Amidst the harsh competition over the development of new products around the world, rapid prototyping, especially rapid tooling methods have received widespread attention. Amongst the rapid hard tooling methods, thermal spraying can manufacture metal molds without limitation of pattern size. However, it has the disadvantage that only soft metals with low melting points such as zinc alloy can be sprayed to original mold, such as a rapid prototyping model or a natural material pattern, due to their lack of heat resistance and shrinkage of spray metals. So the wear resistance of spray tool is poor, it can be used only for trial or small-lot production. In this study, attempts were made to improve the heat resistance by using composite materials made of ceramic and metal powders as the sprayed original mold materials, and using stainless steel, tungsten carbide alloy, iron--nickel--chromium alloy with excellent wear resistance as spraying materials, respectively. The results show that injection molding spray mold and sheet metal forming spray die can be made by transferring from natural patterns and rapid prototyping models. As the durability and dimensional accuracy of the sprayed tools has sharply improved, the tools can be used for mass production.
- Direct metal laser sintering for rapid tooling: processing and characterisation of EOS parts
Khaing, MW; Fuh, JYH; Lu, L
Journal of Materials Processing Technology (Netherlands), vol. 113, no. 1-3, pp. 269-272, 15 June 2001
Direct metal laser sintering (DMLS) fabricates metal prototypes and tools directly from computer aided design (CAD) data. The process is popular in rapid tooling (RT), since a suitable metal powder can be used to produce the metal parts and tools. The powder system may be pre-alloyed powder or multi-phase powder. The properties of the RT parts, however, depend on its composition and solidification conditions. Accuracy, wear resistance and mechanical properties are critical on choosing the rapid tooling mould as the production-grade tooling. This study includes the design of metal prototypes which are then fabricated by EOS's DMLS. The EOS material system is a mixture of nickel, bronze and copper-phosphide material. The dimensional accuracy, surface roughness, impact toughness, hardness, and strength of EOS parts are measured. SEM pictures of EOS parts are also thoroughly analysed.
- Dynamic tensile reponse of structured alumina-Al composites
Atisivan, R; Bandyopadhyay, A; Gupta, Y
Bulletin of the American Physical Society (USA), vol. 46, no. 4, pp. 90, June 2001
Plate impact experiments were carried out to examine the high strain-rate tensile response of alumina-aluminum composites with tailored microstructures. A novel processing technique was used to fabricate interpenetrating phase alumina-aluminum composites with controlled and reproducible microstructures. Fused deposition modeling (FDM), a commercially available rapid prototyping technique, was used to produce the controlled porosity mullite ceramic preforms. Alumina-Al composites were then processed via reactive metal infiltration of porous mullite ceramics. With this approach, both the micro as well as the macro structures can be designed via computer aided design (CAD) to tailor the properties of the composites. Two sets of dynamic tensile experiments were performed. In the first, the metal content was varied between 23 and 39 wt. percent. In the second, the microstructure was varied while holding the metal content nearly constant. Samples with higher metal content, as expected, displayed better spall resistance. For a given metal content, samples with finer metal diameter showed better spall resistance. Relationship of the microstructural parameters on the dynamic tensile response of the structured composites will be discussed.
- Rapid prototyping with Thermojet object printer offers flexibility for testing parts
Metal Casting Technologies (Australia), vol. 47, no. 2, pp. 45, June 2001
The introduction of a Thermojet 3D solid object printer 10 months ago at the Victorian firm A.W. Bell, has more than halved the lead time for the production of prototype parts. According to the Patterns Manager Mark Smith, a part can now be produced in three weeks whereas using conventional tooling methods could take from 6 to 10 weeks depending on the complexity of the shape. The key to the rapid process is the Thermojet solid object printer. It injects wax in a similar way to an ink jet printer, building up a wax representation of a part using a computer-generated 3D model. Parts produced by Bell so far, range from a small jewelery ring to a car component measuring 500 x 400 x 350 mm. Apart from delivery and cost savings, another advantage of rapid prototyping and the investment casting process is the ability to quickly produce parts in any material the customer requires including most grades of stainless steel, steel, copper or zinc.
- A rapid manufacturing technique for complex metal parts with thin wall
Dong, X-P; Huang, N-Y; Wu, S-S; Fan, Z-T; Liu, H-J
National Foundry Information Network, Foundry (China) (China), vol. 50, no. 6, pp. 321-324, June 2001
Based on the rapid precision shaping technology by VDPC (Vacuum Differential Pressure Casting) combined with the RP (Rapid Prototyping) technology by SLS (Selective Laser Sintering) and the ceramic shell mold precision casting technology, a rapid manufacturing method of the metal parts named 'Rapid Precision Casting (RPC)' process from a computer three dimension solid model to the metal part was investigated. The main advantage of this process was its ability to manufacture the quality and complex Al-alloy metal parts with thin wall. The focal points described in this paper are the technical characters of this process including the rapid making technology of the ceramic shell mold using a SLS plastic prototype and the RPC technology by VDPC. So the key problems for rapid manufacturing the metal parts in the process to develop new products have been solved, and this technology has opened up a new field for applying the RP technology in the foundry industry.
- Rapid manufacturing technologies
Advanced Materials & Processes (USA), vol. 159, no. 5, pp. 32-36, May 2001
Rapid prototyping has advanced to rapid manufacturing in many areas. This survey summarizes reports from several manufacturers about their technologies. (Examined are laser additive manufacturing used to fabricate aerospace components from metal powders; selective laser sintering, with parts built by deposition of material in layers, in the case cited, using stainless steel alloy. Also considered are three dimensional printing, also a powder metallurgy process, which involves infiltration of the fabricated part with a second metal after debinding and sintering. Dynamic magnetic compression, a powder compaction technique utilizing high intensity magnetic fields, is described, as is laser engineered net shaping, and direct metal farbication.)
- Rapid prototyping of masks for through-mask electrodeposition of thick metallic components
Wang, W; Holl, MR; Schwartz, DT
Journal of the Electrochemical Society (USA), vol. 148, no. 5, C363-C368, May 2001
A flexible and inexpensive approach for rapid prototyping of thick masks (approx =130 mu m in height) for through-mask electrodeposition of metallic microstructures is demonstrated. The electrodeposition masks are fabricated directly from a computer-aided design layout by patterning adhesive-backed polyvinyl chloride tape using a CO sub 2 laser. The pliant tape masks can then be transferred directly to planar or nonplanar substrates. We demonstrate the use of the tape mask on a nonplanar substrate by plating a NiFe microcoil on a cylindrical rod. The pattern transfer characteristics of the tape mask are illustrated by plating copper columns on a platinum rotating disk electrode. We also fabricate a two-level NiFe criss-cross structure to show how these tape masks can be used to build structures in three dimensions. Limitations of the existing laser system permit minimum lateral feature dimensions of 130 mu m, though the method developed here should readily scale down in feature dimensions using a higher energy pulsed laser. Substrate: stainless steel and Pt (with, respectively, NiFe and Cu coating materials).
- Recent trend about the metal rapid prototyping using powder
Funtai Funmatsu Yakin Kyokai, Journal of the Japan Society of Powder and Powder Metallurgy (Japan), vol. 48, no. 5, pp. 415-421, May 2001
The rapid prototyping technology was born with the development of laser stereolithography. At the beginning, metal products were made by replication using laser stereolithography models as the master. Since then, numerous developments on the use of various materials for the layer lamination method, the basis of the RP method, have been attempted. This paper discusses the trends of fundamental developments and the methods of using metal powder in RP.
- Development of a welding system for 3D steel rapid prototyping process
Yang, S; Han, M; Wang, Q
China Welding (China), vol. 10, no. 1, pp. 50-56, May 2001
Metal device rapid prototyping with welding is one of the research interests at present. A controlled inertial droplet transfer MAC welding (CIDTMAGW) process was developed for the 3D steel device rapid prototyping with metal deposition. In this process, by using a special designed wire feeder, a controlled inertia is imposed on the droplet formed on the wire tip and combines with the arc force to make it detached. Thus, according to the requirements of rapid prototyping, the arc heat and the droplet detaching force can be separately controlled to attain a stable and satisfactory metal deposition process. A CIDTMAGW system and a testing manipulator for the 3D steel device rapid prototyping are presented. The required software is completed as well. The experiments proved that the geometric formation of the rapid prototyping device with welding deposition is well agreed the data of the device CAD modeling. The surface of the deposited device is comparatively smooth.
- Development of rapid tooling for sheet metal drawing using nickel electroforming and stereolithography processes
Yarlagadda, PKDV; Ilyas, IP; Christodoulou, P
Journal of Materials Processing Technology (Netherlands), vol. 111, no. 1-3, pp. 286-294, 25 Apr. 2001
Tooling is an important area in the manufacturing of various sheet metal products. This aspect can be extremely expensive as well as time consuming. The increase in the complexity of tooling for any operation results in a corresponding increase in the time and costs required in developing such tooling. The ideal candidate operations for rapid tooling (RT) have been those for which it is difficult to develop tooling by the usual methods. The quest is to produce complex tooling quickly and at low cost. This paper describes the development of RT techniques for the production of sheet metal drawing tooling by using a combination of stereolithograhy and nickel electroforming processes. Two types of prototype tools have been designed and manufactured. The first type is a stereolithography QuickCast pattern infiltrated with aluminium-filled epoxy designated as QuickTool, and the second type has been manufactured by combining stereolithography technique with the nickel electroforming process. While the QuickTool may be indeed rapidly manufactured it can be only a prototype tool, as the material it is made of does not render much durability. On the other hand, the nickel electroformed tool is far more durable and can withstand more extreme working conditions. By combining nickel electroforming and the stereolithography process, press tools for sheet metal forming have been successfully produced. Further, the developed tools have been evaluated in the press metal forming process by producing components with 0.8 mm aluminium sheets.
- Integration of rapid prototyping and CAE in mould manufacturing
Kuzman, K; Nardin, B; Kovac, M; Jurkosek, B
Journal of Materials Processing Technology (Netherlands), vol. 111, no. 1-3, pp. 279-285, 25 Apr. 2001
In order to shorten the manufacturing time for new products and their moulds, the use and the development of modern techniques are critical. One of such technologies is the rapid prototyping method, which enables the designer and the customer to see the physical presentation of a new product which will be ready for marketing in the period of 3-6 months, already at the early stage of its development. During this period of 3-6 months, the mould must be manufactured and the product must be placed to the market. In this comprehensive R and D work, modern computer techniques must be applied. With the help of computer aided numerical simulations, solving of the greater part of the problems that can emerge during the product and/or mould manufacturing can be predicted. This paper is a result of the co-operation between three Slovenian companies in the development of new products. It starts with the rapid prototyping and computer simulations in the development phase of the product. The same CAE approach will be used in the implementation of modern mould manufacturing techniques, the whole development of the products being treated as an industrial implementation of concurrent engineering methods.
- Application of laser measuring, numerical simulation and rapid prototyping to titanium dental castings
Wu, M; Tinschert, J; Augthun, M; Wagner, I; Schadlich-Stubenrauch, J; Sahm, PR; Spiekermann, H
Dental Materials (Netherlands), vol. 17, no. 2, pp. 102-108, Mar. 2001
This paper describes a method of making titanium dental crowns by means of integrating laser measuring, numerical simulation and rapid prototype (RP) manufacture of wax patterns for the investment casting process. By using the integrated scanning simulation, RP pattern and casting procedure, cast crowns, free of porosity, with excellent functional contour and a smooth surface finish, were obtained from the first casting trial. The coupling of laser digitizing and RP indicates a potential to replace the traditional 'impression taking and waxing' procedure in dental laboratory, with the quality of the cast titanium prostheses also being improved by using the numerically optimized runner and gating system design.