Integrating digital design and fabrication and craft production

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 61-63).This thesis examines if methods of manual craft production can be utilised to overcome the indeterminacies of physical materials and processes that hinder Digital Design and Fabrication (DDF). Indeterminacies in physical materials and processes are considered to be errors that prevent DDF from achieving its stated goal of a seamless transition from digital model to physical artefact. One of the definitions of craft, by contrast, is "(potentially) error through and through...[where error is]... an incomputable deviation from the norm" (Dutta, 2007, p. 211). This concept of error as being 'incomputable' is analysed using theories from computation, systems theory and sociology to formulate a definition of material craft production for this thesis. Material craft production is then compared to the concept of digital craft and it is argued that digital craft is limited in its capacity to negotiate physical materials and processes. Tools from systems theory are then used to propose a model describing material craft production. This model is called the Sensing-Evaluating-Shaping (SES) model. The validity of the SES model is tested through case studies of material craft production. The SES model is analysed using systems analysis tools and a role for DDF is proposed within the SES model, giving rise to digital SES production. The ability of digital SES production to negotiate indeterminacies in physical materials and processes is tested through the fabrication of a series of increasingly complex physical artefacts.by Ayodh Vasant Kamath.S.M

Robotic Manipulation of Environmentally Constrained Objects Using Underactuated Hands

Robotics for agriculture represents the ultimate application of one of our society\u27s latest and most advanced innovations to its most ancient and vital industry. Over the course of history, mechanization and automation have increased crop output several orders of magnitude, enabling a geometric growth in population and an increase in quality of life across the globe. As a challenging step, manipulating objects in harvesting automation is still under investigation in literature. Harvesting or the process of gathering ripe crops can be described as breaking environmentally constrained objects into two or more pieces at the desired locations. In this thesis, the problem of purposefully failing (breaking) or yielding objects by a robotic gripper is investigated. A failure task is first formulated using mechanical failure theories. Next, a grasp quality measure is presented to characterize a suitable grasp configuration and systematically control the failure behavior of the object. This approach combines the failure task and the capability of the gripper for wrench insertion. The friction between the object and the gripper is used to formulate the capability of the gripper for wrench insertion. A new method inspired by the human pre-manipulation process is introduced to utilize the gripper itself as the measurement tool and obtain a friction model. The developed friction model is capable of capturing the anisotropic behavior of materials which is the case for most fruits and vegetables.The limited operating space for harvesting process, the vulnerability of agricultural products and clusters of crops demand strict conditions for the manipulation process. This thesis presents a new sensorized underactuated self-adaptive finger to address the stringent conditions in the agricultural environment. This design incorporates link-driven underactuated mechanism with an embedded load cell for contact force measurement and a trimmer potentiometer for acquiring joint variables. The integration of these sensors results in tactile-like sensations in the finger without compromising the size and complexity of the proposed design. To obtain an optimum finger design, the placement of the load cell is analyzed using Finite Element Method (FEM). The design of the finger features a particular round shape of the distal phalanx and specific size ratio between the phalanxes to enable both precision and power grasps. A quantitative evaluation of the grasp efficiency by constructing a grasp wrench space is also provided. The effectiveness of the proposed designs and theories are verified through real-time experiments. For conducting the experiments in real-time, a software/hardware platform capable of dataset management is crucial. In this thesis, a new comprehensive software interface for integration of industrial robots with peripheral tools and sensors is designed and developed. This software provides a real-time low-level access to the manipulator controller. Furthermore, Data Acquisition boards are integrated into the software which enables Rapid Prototyping methods. Additionally, Hardware-in-the-loop techniques can be implemented by adding the complexity of the plant under control to the test platform. The software is a collection of features developed and distributed under GPL V3.0

A Study On Parametric Appraisal of Fused Deposition Modelling (FDM) Process

The manufacturing industries are contemplating to develop new technologies for production of complex end use parts possessing high strength and low product development cycle in order to meet the global competition. Rapid prototyping (RP) is one of the proficient processes having the ability to build complex geometry parts in reasonably less time and material waste. Fused deposition modelling (FDM) is one of the RP processes that can manufacture 3D complex geometry accurately with good mechanical strength and durability. Normally, the FDM process is a parametric dependant process due to its layer-by-layer build mechanism. As FDM build parts are used as end use parts, it is prudent to study the effect of process parameters on the mechanical strength under both static and dynamic loading conditions and wear (sliding) behaviour. In order to investigate the behaviour of build parts in a systematic manner with less number of experimental runs, design of experiment (DOE) approach has been used to save cost and time of experimentation. As the selection of input process parameters influence on build mechanism, the mechanical properties and wear behaviour of FDM build parts change with process parameters. Notably, the raster fill pattern during part building causes FDM build parts to exhibit anisotropic behaviour when subject to loading (static or dynamic). In this research work, an attempt has been made to minimise the anisotropic behaviour through controlling the raster fill pattern during part building by adequate selection of process parameters. Statistical significance of the process parameters is analysed using analysis of variance (ANOVA). Influence of process parameters on performance characteristics like mechanical strength, fatigue life and wear of build part is analysed with the help of surface plots. Internal structure of rasters, failure of rasters, formation of pits and crack are evaluated using scanning electron machine (SEM) micro-graphs. Empirical models have been proposed to relate the performance characteristics with process parameters. Optimal parameter setting has been suggested using a nature inspired metaheuristic firefly algorithm to improve the mechanical strength. Finally, genetic programming (GP) and least square support vector machine (LS-SVM) are adopted to develop predictive models for various performance characteristic

Computer aids for process model-building

Imperial Users onl

Exploitation and exploration of PCR in microfluidic systems with gradient temperature environments

The main goal of the work was to establish a wholesome picture off all relevant processes for a sample-in, answer out genetic system and to integrate the whole process on a one step device from sample collection to final result. The genetic analysis process consists of ideally three steps: sample preparation, chemical reaction, and analysis. Each of the steps is different and requires a specific environment, where sample preparation might use additives, they might later interfere with the reaction itself or lead to misleading results in the analysis phase. It was found to be quite a challenging process to synchronize the three without compromising each other efficiency. The design of the devices was a gradual process with an iterative approach. The initial trials were focused on enabling on-chip PCR with spatial melting analysis. In the later work, sample preparation was embedded into the process, though at the cost of reaching the used fabrication method limitations. Apart from the challenges of integrating the process into one complete entity, the gradual enhancement of the system in respect to size and performance consistency was pursued. A range of applications and variations to the devices were fabricated each representing a unique solution to many modern-day problems

Mass Production Processes

It is always hard to set manufacturing systems to produce large quantities of standardized parts. Controlling these mass production lines needs deep knowledge, hard experience, and the required related tools as well. The use of modern methods and techniques to produce a large quantity of products within productive manufacturing processes provides improvements in manufacturing costs and product quality. In order to serve these purposes, this book aims to reflect on the advanced manufacturing systems of different alloys in production with related components and automation technologies. Additionally, it focuses on mass production processes designed according to Industry 4.0 considering different kinds of quality and improvement works in mass production systems for high productive and sustainable manufacturing. This book may be interesting to researchers, industrial employees, or any other partners who work for better quality manufacturing at any stage of the mass production processes

National Educators' Workshop: Update 95. Standard Experiments in Engineering Materials Science and Technology

This document contains a collection of experiments presented and demonstrated at the National Educators' Workshop: Update 95. The experiments related to the nature and properties of engineering materials and provided information to assist in teaching about materials in the education community

Laser direct-write of optical components prepared using the sol-gel process

Research in manufacturing techniques for novel and cost effective optical components has focused on versatile new materials and low temperature processing. The laser direct-write of sol-gel optical films has the potential for addressing these two needs for the fabrication of photonic components for rapid prototyping purposes. The combination of Solid Freeform Fabrication (SFF) and Direct-Write (DW) approaches to manufacturing, along with the use of high optical quality materials prepared by the sol-gel process, can result in optical components produced with maskless techniques and with the potential of being used as real products. The fundamental approach in this research consisted in four steps. Initially the sol was synthesized under controlled atmospheric conditions. This was followed by the deposition of the sol-gel thin films by spin coating. After deposition the film was thermally and in some cases chemically treated. The final step involved the use of a laser source for photothermal or photochemical processing of the film, translating the sample through an XY stage. This research provides a detailed study of the preparation procedures of various sol-gel materials (inorganic and hybrid organic/inorganic), with the goal of developing a repeatable and reliable process of high optical quality films. The main experimental aspects explored were the synthesis, deposition, thermal and laser processing of the sol-gel materials. It also presents experimental results that demonstrate light propagation through a simple waveguide made by the proposed process. In addition, this research provides an example of the importance of using design methodology and systems design techniques, as effective strategies for the development of innovative manufacturing processes that involve a great number of parameters. The results of this research set the groundwork for the development of a fully automated direct-write SFF machine that is capable of depositing high optical quality sol-gel films, thermally treating the films, and using a laser to direct-write the structures on inorganic or hybrid organic/inorganic glassy matrices.Mechanical Engineerin

A New Flexible and Multi‐purpose System for Printing 3D Microstructures with Heterogeneous Materials for Tissue Engineering

Tissue engineering is a regenerative medicine approach that combines the applications of engineering methods, material science, and biology research toward the development of biological substitutes that restore, maintain, or improve human tissue or organ function. It has appeared as a rapidly expanding field to address the organ shortage problem and comprises tissue regeneration and organ substitution. A variety of freeform fabrication methods for constructing tissue scaffolds have been developed due to the feasibility of producing scaffolds with customized external shape and predefined internal morphology, allowing accurate control of pore sizes and pore distribution. A new type of solid freeform fabrication (SFF) machine combined with a novel heterogeneous algorithm based on Automatically Programmed Tools (APT) language has been developed to construct hydrogel scaffolds and porous structures. In this study, the system was connected into a PC to act as a high‐performance servo controller for monitoring the control of a three axis x‐y‐z moving arm. The printing procedures were repeated layer‐by‐layer to form a 3D structure. Several biocompatible or thermosensitive materials such as PEG‐PLGA‐PEG triblock copolymer, poly (ε‐caprolactone) (PCL), and a composite of sucrose‐based mixture have been printed by this new three‐dimensional direct printing machine and the experimental results are discussed with respect to potential applications. The SFF technique will allow us to easily control the porosity and the interconnectivity of the pores. However, some enhancements must be achieved in order to obtain optimal resolution of the fabricated 3D scaffolds. The modification of several dominant parameters of the deposition of the biopolymer such as the traveling speed, extrusion speed, flow rate, layer height, nozzle diameter, biopolymer concentration, viscosity and mechanical properties, as well as the design of the scaffold, will lead to the fabrication of optimized 3D scaffolds. Our self‐designed biomaterial SFF system has notable advantages over other commercial SFF machines, including: 1. Changeable printing nozzles for materials with different viscosities and compositions. 2. Reconstructible system setup for different printing purposes. 3. Capability for heterogeneous printing. 4. User‐friendly software development 5. Economical system design. The study of the hardware and software and their integration are described and its new heterogeneous printing algorithm is discussed for multiple purpose uses. The integrated software has been developed to link all components of the control system together and it is easy to adapt to different applications. In addition, PCL scaffolds, sucrose structures, and heterogeneous structures have been fabricated and tested with our SFF system. The optimization of dominant parameters for the fabrication of 3D scaffolds with desired pore sizes in the range of 100‐500 μm was confirmed by light microscopy, and we have shown that our system is capable of fabricating heterogeneous structures efficiently and economically. The system also demonstrated potential for modifications to be adapted for directly and accurately implanting cells for tissue regeneration based on the CAD system design.Ph.D., Mechanical Engineering and Mechanics -- Drexel University, 201

Development of a virtual reality milling machine for knowledge learning and skill training

Current methods of training personnel on high cost machine tools involve the use of both classroom and hands on practical training. The practical training required the operation of costly equipment and the trainee has to be under close personnel supervision. The main aim of this project is to reduce the amount of practical training and its inherent cost, time, danger, personal injury risk and material requirements by utilising a virtual reality technology. In this study, an investigation into the use of Virtual reality for training operators and students to use the Milling Machine was carried out. The investigation has been divided into two sections: first the development of Milling Machine in the 3D virtual environment, where the real machine was re-constructed in the virtual space. This has been carried out by creating objects and assembling them together. The complete Milling machine was then properly modelled and rendered so it could be viewed from all viewpoints. The second section was to add motion to the virtual world. The machine was made of functions as for the real machine. This was achieved by attaching Superscape Control Language (SCL) to the objects. The developed Milling machine allows the users to choose the material, speed and feed rate. Upon activation, the virtual machine will be simulated to carry out the machining process and instantaneous data on the machined part can be generated. The results were satisfactory, the Milling Machine was modelled successfully and the machine was able to perform according to task set. Using the developed Virtual Model, the ability for training students and operators to use the Milling Machine has been achieved