Adaptive layer approximation of free‐form models using marching point surface error calculation for rapid prototyping

In this chapter, we address various issues related to data processing for rapid prototyping. In contrast to traditional material removal processes, rapid prototyping techniques build a part by incrementally adding materials layer by layer (Kruth 1991, Barequet and Kaplan 1998), so they are also called layer-based manufacturing or layered manufacturing. The processes are fully automatic and offer a number of competitive advantages over traditional manufacturing processes. Hence, they are particularly useful for rapid product development. The entire process for model prototyping is illustrated in Figure 5-1 and can be summarized as follows: CAD modeling: The first step in rapid prototyping is to prepare a computer-aided design (CAD) model of the object to be fabricated using layer based manufacturing processes. For most of the available RP technologies, a solid model with complete topological and geometric information is required. STL interfacing: STL is the de-facto standard for the rapid prototyping industry. It is a file format for approximately defining an object using triangular facets. When a CAD model is available, the entire part geometry is converted into STL format based on a tolerance for accuracy control. Part orientation: Before processing for prototyping, a RP engineer needs to figure out the specific orientation in which the prototype model will be produced. Part accuracy, the amount of supporting material required and ease of post-processing are important factors influencing part orientation determination. Support generation: Depending on the specific RP process to be used, one may need to further define support structures for supporting down-facing areas during part build-up. Support generation can be done on the basis of a STL model or the original CAD model. Model slicing and tool path generation: In contrast to material removal manufacturing technologies, rapid prototyping technologies refer to a class of layer-based material increase manufacturing processes. The digital model of the object and related support structures need to be sliced layer by layer. For each layer, a set of surface contours is obtained and a tool path is defined within the material area for model production in a layer-wise fashion. Model production on a RP machine: The produced tool path is sent to a RP machine for building up the prototype model, including support, layer by layer. Post-processing: Depending on the RP process involved, a post-processing step might be needed for post-curing in the case of stereolithography, for infiltration and furnace sintering in the case of SLS, and/or for removing the support structures and surface polishing in the cases of most other RP processes.

Prototypes of a design are always needed for the purposes of visualisation and evaluation for manufacturability, functionality, and aesthetic appearance. Since the prototyping process requires a significant amount of cost and time, various rapid prototyping processes have recently been introduced. However, it is usually necessary for a part built up by a rapid prototyping system to be finished by a post-processing process, in which the stair steps on the surfaces, the support structures (if they exist), and the unprocessed material are eliminated. This post-processing is usually done manually and is a time-consuming task. Eliminating the trapped volumes (the volume of the unprocessed material entrapped by the solidified portion) is sometimes impossible in some processes. This study provides a designer with a tool to detect the existence of trapped volumes and to calculate the quantity in a given build-up direction, so that a suitable build-up direction is chosen or the part is built in pieces to avoid the problems caused by the trapped volumes. Since the proposed algorithm can efficiently calculate the amount of the trapped volumes in any build-up direction, it has the potential for such applications as optimising the build-up direction to minimise the trapped volumes.

A new approach to remove point data with Delaunay triangulation is introduced to deal with the size problems of the STL file and the difficulties in the operation of the rapid prototyping (RP) process. The selection of a group of triangles, based on the angle, is used for a robust and reliable implementation of the Delaunay triangulation method. The developed software enables the user to specify the criteria for the selection of the group of triangles by the angle between triangles, the percentage of reduced triangles, and the allowable area. This approach can be used to reduce the measuring data from the laser scanner, thus save the handling time of point data during the modelling process and is useful for verifying and slicing the STL model during the RP process.

A model for interfacing geometric modeling data with rapid prototyping systems

It is a rapid prototyping and manufacturing process that deposits metals and ceramics by local heating of a substrate with a laser. Laser Chemical Liquid Deposition (LCLD) process planning requires new efforts due to its unique characteristics. Based on LCLD system powered with a 50 W Fibers-laser, a set of experiments performed was described. The morphologies of the metals deposits were studied while varying laser power, chemical liquid reagent concentration, scanning speeds and scanning patterns, and explore process issues in using LCLD to create multi-layer metals structures were addressed. Through studies of the LCLD process, the unique deposit characteristics were identified. The spatial resolution is potentially very fine, depending on the accuracy of stage or laser movement, and the size of the laser spot used for the localized heating. Multi-layered structures require an understanding of interlayer adhesion and the propagation of geometric anomalies through multiple layers. It can build conformal layers (conform to non-planar substrates) and thin walls. Current research efforts focus on the creation of more advanced three-dimensional metals objects through the use of multi-layered deposition.

During the last four decades laser beam machining has been used as a powerful tool in rapid prototyping. Nd:YAG lasers are most widely used in machining of engineering materials, especially silicon for Micro-Electro-Mechanical-Systems (MEMS). Apart from laser micro-welding or laser micro-drilling, laser micro-cutting is one of the most important processes in rapid prototyping. In recent years the researchers have focused on the parameters of the laser beam, such as the pulse duration, the wavelength, the laser power, and the repetition rate. All these parameters depend on the laser system and can be varied in a wide range. The basic parameters - the focus position, the pulse overlap, the track overlap, the number of tracks, and the influence of wobbling - were mostly neglected, although their effect on laser micro-cutting is essential and independent of the above mentioned parameters of the laser system. This research work investigated laser micro-cutting holes in silicon wafers with a nanosecond Nd:YAG UV laser and determines for each parameter the number of scans, the required manufacturing time, the diameter on the laser beam output side as well as on the input side, and the corresponding flank angle.

In the dynamic and customer-centric business landscape of the 21st century, organizations are increasingly turning to innovative methodologies to drive meaningful and effective solutions to complex problems. This paper explores the integration of LEGO® SERIOUS PLAY® into design thinking sessions as a method for rapid prototyping with a focus on customer-centricity. By combining the principles of design thinking, rapid prototyping, and LEGO® SERIOUS PLAY® methodology, this study aims to investigate how the construction of these scenes, coupled with storytelling and pitch development, can facilitate the exploration of customer pain points and gains to inform solution ideation and iteration. A detailed case study is presented to illustrate the application of this approach, highlighting the process from problem identification to prototype creation and feedback gathering. Through analysis and reflection, this paper identifies key insights into the effectiveness of using LEGO® SERIOUS PLAY® for rapid prototyping within design thinking sessions, as well as challenges and opportunities for future research and practice. Ultimately, this study underscores the potential of prototyping as a valuable tool for fostering creativity, collaboration, and customer-centric innovation in organizations seeking to drive positive change and deliver impactful solutions. We are exploring how using this approach can help organizations unlock the full potential of their teams, drive breakthrough innovation and create lasting impact in an ever-changing world. OBJECTIVES: Exploration of LEGO® SERIOUS PLAY® within the design thinking process for rapid prototyping in the context of envisioning the future of cities. Specifically, the paper aims to demonstrate how these methodologies can foster creativity, collaboration, and customer-centric innovation, particularly in uncertain and complex environments as categorized by the Stacey Matrix. METHODS: This study employs a series of 20 design thinking sessions using LEGO® Serious Play to engage diverse stakeholders in imagining the city of 2030. The methods include defining the initial problem statement, conducting empathy exercises to understand user needs and utilizing LEGO® SERIOUS PLAY® for constructing scenes that highlight customer pain points and gains. Developing and presenting pitches and stories based on these LEGO® models and reframing and recreating prototypes based on cross-pollination of ideas. RESULTS: Participants quickly generated rapid prototypes that visually and tangibly represented their ideas. Several specific problems were identified, each accompanied by customer-centric solutions. The use of LEGO® SERIOUS PLAY® facilitated deeper engagement, creativity, and collaboration among participants. Storytelling and pitching helped effectively communicate the envisioned future scenarios and solutions. Feedback from stakeholders provided valuable insights that guided iterative refinement of the prototypes. CONCLUSION: Design thinking, when combined with LEGO® SERIOUS PLAY®, proves to be an effective methodology for rapid prototyping and innovation in complex and uncertain environments. The approach encourages a customer-centric mindset, ensuring that solutions are relevant and impactful. The iterative process of prototyping and feedback leads to continuous improvement and refinement of ideas. LEGO® SERIOUS PLAY® enhances creativity and collaboration, making it a valuable tool in the design thinking toolkit. This integrated methodology can help organizations navigate and transform ambiguity into actionable opportunities for innovation, particularly in the context of future urban planning and development.

The emergence of stereolithography in 1998 is a milestone for an entirely new class of layer-based manufacturing processes. This new manufacturing approach which allows direct digital manufacturing from CAD to a physical part, is the most flexible and versatile form of fabrication process. This paper provides an overview on the development of digital additive manufacturing processes, commonly known as rapid prototyping processes, and chart its progress and challenges towards the ultimate goal of rapid manufacturing with supporting case examples.

Subject of Research.The paper presents the study of methods for control of rapid prototyping processes with the use of technical vision hardware and software system. Product monitoring is a crucial function of any manufacturing process. It becomes more important when the monitoring is performed during the the product manufacturing. Three-dimensional printing technology requires this kind of monitoring system in order to improve the visual and durable qualities of the product, optimize the material costs and the speed of manufacturing. Method. The parameters of the optical system for capturing images in the printing process are defined in theory. Optical systems are selected providing the necessary image quality. The analysis of the camera placement configuration has been carried out to match optimally the task. The analysis was based on overall dimensions of the 3D printer, its working area and free space in the printer case. The ways for solution of software part problems were analyzed. Main Results. A mathematical apparatus was developed for calculation of the optical system parameters of a technical vision complex. Different variants of optical systems were selected for efficiency verification of the hardware and software system. Different methods for development of programs and algorithms for data processing from video cameras were considered. Practical Relevance. The development of the hardware and software system that controls the rapid prototyping process has a significant benefit in expanding the possibilities of automating rapid prototyping processes. The results of the work can be useful in quality control of the product during its manufacturing, in disclosure of deviations from the virtual three-dimensional model, in development of recommendations for control commands update in order to improve the quality and increase the speed of product manufacturing.

A novel roll powder sintering (RPS) technology is proposed for processing real plastic, ceramic, metal and other 3-D objects 1m³ (or more) in volume directly from a CAD model within several hours. The breakthrough advantages of the technology are compared to the dominant rapid prototyping and manufacturing (RP&M) processes that are currently on the market.

Conventional shaping processes for ceramics are mostly based on a powder‐technological molding process using a negative mold and subsequent thermal compaction. Especially for prototypes and small lot series of microcomponents the outlay for molds are the major costing factor. Consequently the use of rapid prototyping (RP) processes can decisively reduce the costs and time in product development of ceramic microcomponents. In spite of the fact, that a large number of freeform fabrication techniques for different materials were developed in recent years, most generative techniques of ceramics still have different drawbacks for the fabrication of prototypes and often exhibit limited resolution compared to those of polymers. The combination of RP techniques such as micro stereolithography and ceramic injection molding in a RP process chain can fill in the gap between the limited applicability of solid freeform fabrication of ceramics and the restricted material properties of polymers.

Some of the Rapid Prototyping (RP) processes have seen enormous improvements in the recent past and are racing towards Rapid Manufacturing (RM), the ability to produce end use parts directly from CAD files. While this sounds quite exciting, considering the time-to-market constraints constantly faced by manufacturing engineers, the key question to be answered is whether the processes are truly capable of achieving the required quality standards. This paper addresses this question considering the mechanisms of material consolidation in a couple of RP processes that are currently considered sure candidates for RM. The conclusion is that RM is a possibility, but depends on the outcomes of research and development activities yet to be undertaken in many directions.

PurposeTo discuss integration of the rapid prototyping environmental aspects with the primary focus on electrical energy consumption.Design/methodology/approachVarious manufacturing parameters have been tested on three rapid prototyping systems: Thermojet (3DS), FDM 3000 (Stratasys) and EOSINT M250 Xtended (EOS). The objective is to select sets of parameters for reduction of electrical energy consumption. For this, a part is manufactured in several orientations and positions in the chamber of these RP systems. For each test, the electrical power is noted. Finally, certain rules are proposed to minimize this electrical energy consumption during a job.FindingsIt is important to minimize the manufacturing time but there is no general rule for optimization of electrical energy consumption. Each RP system must be tested with energy consumption considerations under the spotlight.Research limitations/implicationsThe work is only based on rapid prototyping processes. The objective is to take into consideration the complete life‐cycle of a rapid prototyped part: manufacturing of raw material as far as reprocessing of waste.Practical implicationsReduction of electrical energy consumption to complete a job.Originality/valueCurrently, environmental aspects are not well studied in rapid prototyping.

Octree reinforced thin-shell rapid prototyping

In a typical arc spray prototyping process, two metal wires was melt by electric arc at certain distance and sprayed to the mold surface with high speed compressed air from the jet. To prevent failures such as deformation and cracking, homogeneous temperature field distribution was required for every spray layer. This can be achieved by optimizing the processing parameters using numerical simulating of the temperature distribution. The 3-D temperature simulating technology in the rapid prototyping process using arc spray was introduced. A 3-D model for temperature distribution was established using finite element method. In this model, arc spray rapid prototyping is considered as a process in which every molten drop moves along the path and overlays one another. The movement of the heat source was defined by a function. The temperature evolution as a function of time and the temperature distribution gradient of the sprayed layer were simulated. A real-time measurement of the temperature field was also conducted using infrared thermal imaging system. Results show that the simulating fits well with the experimental data.