bluuebunny/crossref_metadata_2025 huggingface dataset:
The Most Probable Optimal Design Method for Global Optimization
Authors: Shi Qinzhong , Hagiwara Ichiro , Takashima Futoshi
Published: February 2021

In this study, to find the global optimum efficiently, holographic neural network is introduced to be an activate function of response surface methodology. Since the accuracy of approximation function near the global optimal design is merely important, techniques to search the region of containing the global optimal design using conditional random seeds, and techniques for finding more, accurate approximation near the global optimal design, using holographic neural network are exploited. In the study, the proposed approach called the most probable optimal design (MPOD) method to pick up one local optimum design which has the biggest probability in the design space. Design example of crash worthiness for the passenger injury with continuous and discrete design variables are shown the validity of the method.
Planar Cable-Suspended Haptic Interface: Design for Wrench Exertion
Authors: Williams Robert L.
Published: February 2021

Cable-suspended robots and haptics interfaces are appealing because of their structural simplicity, high stiffness, and high exerted wrench-to-weight ratio. A major drawback is that cables cannot push but can only exert tension. Therefore, actuation redundancy is required; even so, certain configurations and wrenches will fail since they would require one or more cables to push. The objective of this paper is to present the best design for a planar cable-suspended haptic interface with regard to largest workspace with general wrench exertion in light of this cable tension problem. There are infinite designs with infinite wrenches to apply; therefore, the best and worst designs are found by extensive computer simulation given a reasonable quantification of the problem parameters.
Smooth Collision Avoidance Trajectories: A Dynamic Collision Avoidance Algoritm for Mobile Robots
Authors: Newcomer Jeffrey L.
Published: February 2021

This paper presents an algorithm for generating Smooth Collision Avoidance Trajectories (SCAT). SCAT generation is a method that allows a mobile robot that is moving along a pre-planned path to alter a section of its path, so that it may smoothly exit the original path, avoid a predicted collision, and return to the original path smoothly and on schedule. The SCAT generation algorithm is an improvement over off-line methods, as it requires minimal a priori information, and is more robust than pre-planned methods by its very nature. The SCAT algorithm is also an improvement over on-line schemes that only alter velocity along a pre-planned path, as it is able to avoid collisions in cases that those methods cannot. Details of the SCAT generation algorithm are developed herein, followed by examples of the algorithm in action. Simulation results show that the SCAT algorithm is very dependable, given that it can be provided with reasonably accurate in-formation about the location of dynamic obstacles in its vicinity.
A Geometric Path Planner for Car-Like Robots
Authors: Chen Shiang-Fong , Deng Jiansong
Published: February 2021

This paper presents a simple geometric method for planning collision-free paths for car-like robots. A slabbing method, originally used for free-flying robots, is refined, by taking kinematic constraints and reversal maneuvers into account, for finding efficient nonholonomic paths. Successive configuration spaces are computed for different robot orientations. Resulting configuration spaces are called “orientation levels”. Each orientation level is slabbed by a group of parallel slabbing lines. The slopes of slabbing lines in each orientation level are positioned to have the same orientation as a robot in that level. The resulting slabbing lines act as “rails” to guide the robot. Thus, a robot can only translate straight forward or straight backward, if it keeps moving in a given orientation level. Limiting robot movement to straight forward or straight backward along slabbing lines prevents a robot from violating kinematic constraints, by moving sideways across slabbing lines. Our proposed algorithm has been fully implemented. Performance of our path planner is demonstrated by four examples.
Rational Bézier Line-Symmetric Motions
Authors: Li Shutian , Ge Q. J.
Published: February 2021

This paper brings together line geometry, kinematic geometry of line-symmetric motions, and computer aided geometric design to develop a method for geometric design of rational Bézier line-symmetric motions. By taking advantage of the kinematic geometry of a line-symmetric motion, the problem of synthesizing a rational Bézier line-symmetric motion is reduced to that of designing a rational Bézier ruled surface. In this way, a recently developed de Casteljau algorithm for line-geometric design of ruled surfaces can be applied. An example is presented in which the Bennet motion is represented as a rational Bézier line-symmetric motion whose basic surface is a hyperboloid.
Survey of Available Sensor Technology for Robotic Hands
Authors: Upasani Amit V. , Kapoor Chetan , Tesar Delbert
Published: February 2021

This paper documents a survey of sensor technology for use in robotic hands. This is achieved by studying sensors used in the UTAH/MIT Hand, the Belgrade/USC hand, the Stanford/JPL hand and the Hirzinger Hand. Additionally, off-the-shelf available sensors as well as those under development in research labs are also evaluated. Different types of sensing covered in this report are position, torque, touch/contact force, proximity, vision, and temperature. Different options available for each type of sensing are also outlined. Major attention was given to the contact force sensor, as it is crucial for the grasping task.
Surface and Process Modeling and Off-Line Programming for Robotic Spray Painting of Curved Surfaces
Authors: Balkan Tuna , Arikan M. A. Sahir
Published: February 2021

An algorithm and a computer program is developed for off-line programming of industrial robots for spray painting of curved surfaces. The study is initiated to find a more productive and repeatable, and thus higher quality method for painting of car body components in car body repair shops, where only the deformed region or part is straightened or replaced, and then painted. Body components of a specific car are modeled, and painting strategies, parameters and paths are determined. CAD models of relatively simple surfaces are formed by using the surface generation tools of the software. For parts with more complex surfaces, point data related to the part is collected by using a laser scanner, and this data is used to form the CAD model of the part surface. For paint (coating) thickness distribution analysis, the surface is divided into small elements, and their centroid coordinates and unit normals are determined. These properties are then used together with the spray distance, painting velocity and the paint flow rate flux for paint thickness analysis. Paint flow rate flux through the spray gun is determined by using experimental paint thickness distributions obtained by using different spray gun settings and painting parameters. Besides the technical specifications of the spray gun, air and paint nozzles, and paint needle; basic settings like paint tank pressure and gun needle-valve position affect paint cone angle and paint flowrate, which finally characterize the spray painting process. After deciding on an acceptable paint thickness distribution, the robot program is generated in the robot’s programming language. While moving along the path, the Cartesian position, velocity and orientation of the gun are necessary. Since there is no Cartesian input function available in the controller of the industrial robot used in this study, an inverse kinematic solution algorithm is developed to obtain the generated data in the joint space of the manipulator.
Design and Experimental Verification of a New Direct Cold Drawing Die for Section Rod From Round Bar
Authors: Wang Liping
Published: February 2021

This paper presents the design and verification of a new direct cold drawing die used for drawing of hexagon/square section rods from round bars. Advanced computer-aided design and analysis tools are utilized to assist in the design of die profile and manufacturing parameters. The strain gage method is adopted to measure the mean drawing force and verify the die design and machining process.
Optimal Synthesis of a Robomech: Procedure and Application
Authors: Canfield Stephen , Kolanupaka Giridhar , Smaili Ahmad
Published: February 2021

This paper presents and compares two optimal synthesis techniques for direct application in creating a robomech-II, the second manipulator presented in a new class of linkage arms called Robomcchs. The first optimal synthesis approach will solve the problem as a nonlinear optimization, with a subset of the device parameters described in a linear system and solved directly in a least squares sense. The second approach will employ a least squares optimization using Lagrange Multipliers to contend with nonlinear constraints. In this paper, each optimal synthesis procedure is developed for the general case and then applied to robomcch-II through an example.
Catalog-Based Customization
Authors: Chidambaram Bala , Agogino Alice M.
Published: February 2021

This paper develops a new method for implementing mass-customization, namely, the customization around standard products, or catalog-based customization. The method addresses the customization requirements of a class of products that are complex in configuration, multi-functional and structurally similar. We formulate catalog-based customization as an optimization problem consistent with the manufacturer’s goal of incurring minimal costs in the redesign of existing standard components, while meeting customer specifications and satisfying design constraints. The ‘catalog-based’ nature of the formulation raises concomitant issues of cost function development and problem simplification/solution. We identify the generational structure as best suited to exploit the cost data in existing catalogs and construct a product cost function. The cost-estimation methods used by the generational structure in the construction are identified as weight-based — for modeling the material costs, and methods based on similarity principles and regression analyses — for the production costs. The optimization formulation of catalog-based customization may be simplified by an a priori identification of a standard catalog design as the customization basis. This is accomplished with function costing — a cost-estimation hypothesis that uses product functionality to develop an approximate cost-estimate. The function-costing estimate is also used to abstract features from the standard base design into the optimization formulation. The preferred solution strategy for the optimization formulation is identified as genetic algorithms. We apply the customization method developed to Brushless D.C. Permanent Magnet (BDCPM) motors and obtain optimal minimal cost custom designs (from the standard designs of a BDCPM motor family) for different sets of customer requirements.
Optimal Design of Multibody Systems by Using Genetic Algorithms
Authors: Datoussaïd Sélim , Verlinden Olivier , Conti Calogéro
Published: February 2021

The design step of multibody systems requires in some specific cases an optimization process, in order to determine the set of parameters which lead to optimal kinematic or dynamic performances. The aim of this paper is to propose an optimal design method adapted to general multibody systems and submitted to kinematic and/or dynamic time-dependent criteria. The optimization process is based on stochastic techniques referred to genetic algorithms, which are inspired from natural evolution and can often overtop classical optimization methods when applied to practical problems. Illustrative examples are given in the context of the optimization of the kinematics of a motorcar suspension and the lateral dynamics of an urban railway vehicle.
Extended Bintrees for Representing the Spatial Decomposition of 3D Objects
Authors: Bao Zhuojun
Published: February 2021

Extended bintree as a new class of approximation models for solid modeling is presented in this paper. Based on the bintree data structure, it allows face, edge and vertex node types as well as the classical black, white and grey nodes. Using extended bintrees, Boolean operations can be carried out and are used to generate a new object representation. The required memory is less than that in term of bintree, that is a generalization of the quadtree and octree. This gives a new efficient way to represent polygonal and polyhedral objects exactly. The extended bintree is a general method of binary cellular models. From that, the corresponding other binary models can be easily deduced. The extended bintree representation can be used in image processing and model converting in CAD/CAM systems.
Integration of Solid Modelling and FEM Analysis for the Design of Scroll Compressors
Authors: Jiang Z. , Cheng K. , Harrison D. K.
Published: February 2021

This paper presents an integration approach to solid modelling and finite element method (FEM) analysis on the components design of a scroll type of compressors which are becoming popular and widely used in refrigeration and air conditioners. It is time consuming to design and manufacture a scroll compressor since its two key components are complex shaped and high precision requirements. The authors use C++ programming and Pro/ENGINEER to implement the proposed approach and associated design development. Constructive solid geometry (CSG) modelling of two scroll components are created and presented. FEM analysis is used to further consolidate the modelling with respect to force and heat influences, etc. The paper concludes with a discussion on the potential of the proposed approach in mechanical product design.
Direct Method of Blank Determination in Stamping
Authors: Durand Daniel , Girot Franck , Coupard Dominique
Published: February 2021

Usually, the exact geometry of the blank of a stamping is obtained by successive corrections of a presupposed blank subjected to the operation of stamping or its simulation.

This paper presents an innovating method of direct predetermination of the blank. The part is set flat that it gives the required part when subjected to the action of the tool for stamping. The setting flat presents splits and the part carried out some discontinuities. The setting flat is then deformed to reabsorb the splits and the shape thus obtained is the optimized blank. This method is illustrated and validated on a rectangular cup by a comparison between the calculated blank and the part obtained.
Matching Design Tasks to Knowledge-Based Software Tools: When Intuition Does Not Suffice
Authors: Amen R. , Rask I. , Sunnersjö S.
Published: February 2021

Choosing methods and tools to automate engineering design tasks has farreaching implications. A system that is first established for a limited task may later require being scaled up and maintained for many years of operational life. As the system grows, the company’s reliance on the system increases and the need for a stable platform to start from becomes critical. The system must be tailored to the specific design process and knowledge structure at hand. The purpose of this work is to present a structured methodology to classify design task(s) and to give guidelines for how this definition should be linked to suitable solution strategies and computerised tools.
A Model for the Prediction of Form Errors in Face Milling and Turning
Authors: Masset Luc , Debongnie Jean-François , Foreau Sylvie , Dumont Thierry
Published: February 2021

A method is proposed for predicting form errors due to both clamping and cutting forces in face milling and turning. It allows complex tool trajectories and workpiece geometries. Error computation is performed by the finite element method. An experimental validation of the model for face milling is presented. Two industrial applications are produced in order to demonstrate the capabilities of the method.
Controlling Form Errors From 3D Measures
Authors: Debongnie Jean-François , Masset Luc
Published: February 2021

Owing to the fact that a correct evaluation of form errors is particularly difficult by the classical ways, it seems more efficient to develop numerical algorithms from 3D measures. Several methods are described, including direct and iterative ones. A new method is proposed, which is based on Lp-norms and a specialized algorithm. It proved to be the most effective and robust one on every studied application.
A Twinkling Technique for Brownian Moves in Optimization Processes
Authors: Mekhilef Mounib
Published: February 2021

This paper outlines a computational method for constructing displacements subspaces in optimization processes. In the first section, we present the research field. The second section is devoted to the mathematical formulation of the twinkling technique. The basic idea is that moving the state vector according to random subspaces while generating a new point is better than displacements in the whole optimization space. We then provide in the third section two different problems. We have made the choice to study the behavior of this technique on non specific areas to show that this efficiency is not problem dependent. The first case concerns the general NP-hard problem by the means of the travel salesman problem, the second problem deals with a continuous problem built in a random space. The following section is devoted to some numerical results. We discuss the results and give some orientations for the determination of the optimal subspace dimension. The second part is devoted to the study of the distribution law on the convergence. We compare three laws, the first one is the uniform distribution, the second the normal gaussian and finally we discuss the circular selection of the parameters.
Side Impact Crash Modelling: Development of a Numerical Identification Tool Using Optimization Methods
Authors: Jaskulski Jean-Yves , Mekhilef Mounib
Published: February 2021

Currently, in automotive industry, identification of vehicle crash model parameters on test measurements is a key point. This paper outlines an approach based on optimization methods for this problem in the context of side impacts. It presents the problematic of crash model parameter identification. The engineer’s evaluation criteria of correlation are translated into an optimization objective function. Several optimization strategies are applied to identification of side impact crash model parameters. The comportment on our problem of these strategies are characterized, and numerical results show that the method of tabou search provides a good solution.
Modeling Tolerances and Dispersions of Mechanical Assemblies Using Virtual Joints
Authors: Laperrière Luc , Lafond Philippe
Published: February 2021

This paper presents a novel approach to model the propagation of tolerance buildups in tolerance chains. Starting with a suitable representation of the assembly in terms of its functional elements grouped in pairs (points, curves, surfaces, either real or fictive), we associate a set of six virtual joints to one functional element in every pair, making it possible to simulate moves of this element with respect to others. For these moves to be general, i.e. to represent the manufacturing inaccuracies of a wide variety of manufacturing processes, the six virtual joints are divided into three mutually perpendicular translations and three mutually orthogonal rotations. As these moves are small (dispersions), the theory of small displacements using standard Jacobian matrix computations is directly applicable to model the individual or cumulative effect of any dispersion of any functional element in the chain. This paper describes in details how the Jacobian matrix is computed once the virtual joints have been assigned to the functional elements pairs. An example is provided to demonstrate the potential use of the developed model.
Computer-Assisted Kinematic Tolerance Analysis of a Gear Selector Mechanism With the Configuration Space Method
Authors: Sacks Elisha , Joskowicz Leo , Schultheiss Ralf , Hinze Uwe
Published: February 2021

This paper presents a case study in computer-assisted tolerancing with the configuration space method. We analyze part of a gear selector mechanism in an automotive automatic transmission. The model contains three complex parts with 99 functional parameters. The analysis, which takes less than a minute on a workstation, indicates that the critical kinematic variation occurs in third gear and identifies the parameters that cause the variation. The analysis program handles general planar systems of curved parts with contact changes, including open and closed kinematic chains. It computes the worst-case variation in the system kinematic function and detects potential failure modes due to unexpected qualitative variations in function, such as jamming. It constructs configuration space models of the kinematic variations of the pairs in the system then derives the system variation by composing the pair models.
A Second-Order Method for Assembly Tolerance Analysis
Authors: Glancy Charles G. , Chase Kenneth W.
Published: February 2021

Linear analysis and Monte Carlo simulation are two well-established methods for statistical tolerance analysis of mechanical assemblies. Both methods have advantages and disadvantages. The Linearized Method, a form of linear analysis, provides fast analysis, tolerance allocation, and the capability to solve closed loop constraints. However, the Linearized Method does not accurately approximate nonlinear geometric effects or allow for non-normally distributed input or output distributions. Monte Carlo simulation, on the other hand, does accurately model nonlinear effects and allow for non-normally distributed input and output distributions. Of course, Monte Carlo simulation can be computationally expensive and must be re-run when any input variable is modified.

The second-order tolerance analysis (SOTA) method attempts to combine the advantages of the Linearized Method with the advantages of Monte Carlo simulation. The SOTA method applies the Method of System Moments to implicit variables of a system of nonlinear equations. The SOTA method achieves the benefits of speed, tolerance allocation, closed-loop constraints, non-linear geometric effects and non-normal input and output distributions. The SOTA method offers significant benefits as a nonlinear analysis tool suitable for use in design iteration.

A comparison was performed between the Linearized Method, Monte Carlo simulation, and the SOTA method. The SOTA method provided a comparable nonlinear analysis to Monte Carlo simulation with 106 samples. The analysis time of the SOTA method was comparable to the Linearized Method.
Tolerance Control in Workpiece Fixturing
Authors: Armillotta A. , Biggioggero G. F. , Semeraro Q. , Moroni G. , Polini W.
Published: February 2021

When designing parts with tight tolerances, care must be paid to ensure that specified accuracy can be yielded despite manufacturing deviations. An issue to be considered is how deviations on datum elements propagate on toleranced features, taking into account configuration of locating fixtures used in manufacturing set-ups. The paper focuses on calculating position errors on machined features due to fixture configuration and tolerances on datums. Referring to some examples, it is shown how the most significant factors for tolerance control can be recognised by a proper geometric description of the locating fixture. The analysis is intended as a support to both fixture design and detection of critical aspects of part geometry and tolerancing scheme.
Integrating Tools for Manufacturability Analysis of Assemblies
Authors: Barrón-Cano Olivia M. , Gordillo José Luis
Published: February 2021

This paper presents a modular computer system for manufacturability analysis of robot-made assemblies.

In order to say if a specific design can be assembled in a specific robotic cell, designers must answer a number of questions about sequencing, stability, fixturing, grasping, motion planning, and tool accessibility.

Although several tools have been developed to compute some of the answers needed by designers,. they have been developed in an isolated fashion making hard to integrate their results. Each tool uses its own object models (which highlight some particular analysis features), sets of constraints, scale factors, and base units (inches, mm, etc) leading to incompatibility problems when designers need to chain them, i.e. to use the output from one tool as the input for another one.

Unfortunately, these problems make designers would rather answer their questions by hand, and thus an integrative tool is needed. This paper details the work we have already done in order to build such a tool.
ADN: An Agent-Based Decision Network for Concurrent Design and Manufacturing
Authors: Danesh Mohammad Reza , Jin Yan
Published: February 2021

Engineering design is a complex process. Even in designing a simple product, tens, if not hundreds, of decisions must be made by a single designer or manufacturer. The problem gets more complex when a group of designers work as a team to design an artifact. In this paper, we take a decision-based approach to model design process and introduce an agent-based decision network (ADN) to support concurrent decision-making and collaboration in design and manufacturing. Our research on ADN focuses on making team members consider other members’ decisions when making their owns and attempts to achieve coherent design decisions among designers by explicitly representing and capturing individual design decisions and negotiation processes. To achieve this goal we introduce a decision-based design process model (DDPM) and a condition-based negotiation model (CNM). The DDPM was developed to capture individual designers’ design processes. The CNM was developed to facilitate condition-based negotiation process and to track both conditions generated and decisions made at each design stage for downstream negotiation support. In ADN, each designer is associated with an agent and both the DDPM and CNM are captured and facilitated by agents and are not explicitly visible to designers. Agents generate and utilize the DDPM and CNM information to support their designers. This paper describes the ADN framework in detail, points out its advantages, and presents an application example to demonstrate the effectiveness of the ADN framework.
Characterizing Customer Value for Product Customization
Authors: Du Xuehong , Tseng Mitchell M.
Published: February 2021

Product customization has become an important approach to meet individual customers’ needs. One of major challenges in product customization is to assist customers making informed decisions in terms of the company capability and the value-added by customization. The ramification is not only helping customers selecting the most appropriate products but also helping the company to decide what to design and produce. In this paper, taking into consideration of its diversity, customer value can be measured as the quality utility per unit cost, or the ratio of marginal utility and marginal cost. Customer Value Oriented Product Customization (CVOPC) is developed as a systematic process to quantify the quality utility through guiding customers to make customization choices that reflect the balance of customer-valued quality and cost. A modified conjoint analysis is applied to capture the customer’s utility function of quality in terms of specific product features. A case study of designing module power supplies for a telecommunication system is presented.
Challenges in Robust Concurrent Product Development Across the Supply Chain
Authors: Esterman Marcos , Ishii Kosuke
Published: February 2021

This paper describes challenges faced by companies that form partnership with global suppliers in developing an integrated product. Many experts agree that concurrent product development (CPD) across the supply chain is the next significant challenge in design for manufacturability. Effective management of this process is a key to achieve superior time-to-market and life cycle quality. Drawing on a recent Global Supply Chain Seminar at Stanford, the paper first surveys the challenges faced by various companies ranging from electronics and automotive to aircraft engines. From the survey emerges some key and common issues that these, companies face: cultural barriers, product definition and joint product development practices. The paper then identifies the need for a systematic tool to achieve robust development strategies under uncertainties associated with global partnerships. A proposed robust development approach includes strategies such as key tuning parameters and functional redundancies. The paper concludes by presenting an idealized CPD process and future research agenda.
Optimal Component Consolidation in Molded Product Design
Authors: Fagade Adekunle A. , Kazmer David
Published: February 2021

Per standard DFMA practice, designers are taking advantage of the full capability of manufacturing processes by consolidating multiple parts and functions into fewer, more complex parts. This paper examines the component consolidation issues for injection molded parts. Detailed tooling cost and lead-time models are first developed from industry data; material and processing cost models are established based on analytic and empirical models. Differential calculus is then applied to a generic profit model to establish nonspecific guidelines for component consolidation for both a single and mix of products. A quantitative demonstration of these concepts is also provided for a family of complex internal chassis. The results indicate that some additional DFMA rules are necessary regarding component consolidation. Components should not be combined if: the consolidation does not reduce the number of tools, the components have vastly different quality requirements, the design process is not certain of delivering the product and there is significant sales cost sensitivity, and the manufacturing processes are not capable of delivering high yields of complex products.
Product Variety Deployment and its Optimization Under Modular Architecture and Module Commonalization
Authors: Fujita Kikuo , Sakaguchi Hisato , Akagi Shinsuke
Published: February 2021

Simultaneous design of multiple products has become essential for manufacturing firms to expand design optimization basis. Various viewpoints on this issue have been provided from investigation of practices, but their outcomes still stay on descriptive stages. This paper discusses product variety design under modular architecture and module commonalization toward a computational methodology. It reviews the module based product variety with a mixture of views from customer’s needs, functions, manufacturing modules and hierarchical representation of systems. Based on the consequent framework, this paper also mathematically formulates the problem of product variety design as a 0-1 integer-programming problem in a systematically abstract form, and develops an optimization algorithm based on a simulated annealing technique. These discussion and optimization method are applied to a virtual design problem of television receiver circuits to show their validity and promise.
Designing for Time-to-Market: Predicting the Effects of Product Design on Production Rate
Authors: Govil Manish K. , Magrab Edward B.
Published: February 2021

This paper presents a methodology and a corresponding software tool for estimating a product’s production rate very early in the product development cycle. It evaluates the product’s proposed geometric attributes, materials, manufacturing processes, vendors and assembly methods for each of its components with respect to its affect on the production rate. It does this evaluation by first interactively converting the product’s functional decomposition into a product structure and then into an assembly structure. Then, based on a factory’s resource allocations and vendors’ lead times over the time horizon of interest it computes the production rate, identifies those components that are critical to increasing the production rate and suggests means to improve the fit between the product’s design and the production system. For the example selected it is shown that the methodology indicates that one can increase the production rate by 100% by either (i) modifying the thickness of one component and changing the manufacturing scheme of two other components, or (ii) changing the manufacturing scheme of three components out of the 20 components in the product.
Multidisciplinary Machine Cell Formation for Design of Cellular Manufacturing Systems
Authors: He David , Adamyan Angela
Published: February 2021

Machine cell formation in design of cellular manufacturing systems has traditionally ignored the issues of reliability. As such, the machine cell formation methods have been developed without the explicit considerations of system reliability and maintainability and the systems designed by these methods may have poor reliability and maintainability and hence result in low availability and productivity. In this paper, we discussed how the reliability issues should be incorporated into solving machine cell formation problems. A new formulation for machine cell formation with reliability considerations in cellular manufacturing systems was developed. The formulation is based on multi-attribute utility theory and represents the tradeoff the designers are willing to make between reliability and other design attributes in design of cellular manufacturing systems. An example was used to illustrate the application of the formulation for machine cell formation with reliability considerations. An algorithm for determining the optimal machine cell size in design of cellular manufacturing systems is also proposed.
Selection of Rapid Tooling Materials and Processes in a Distributed Design Environment
Authors: Hermann Amy , Allen Janet K.
Published: February 2021

Rapid prototyping has made a substantial contribution to reducing product development time. Here we discuss rapid tooling, that is, rapid prototyping of production tools, especially injection molds. The rapidly prototyped tools are then used to produce final parts. As the market demands ever more rapid production of parts, at Georgia Tech we are developing a distributed design environment in which the various stakeholders in the product development process can contribute information and expertise. We present the overall vision for the design for manufacture portion of the Rapid Tooling TestBed. The design framework for Rapid Tooling TestBed is based on an attention-directing tool, the Decision Support Problem Technique, in which we postulate that design progress is measured by the types and nature of decisions about the product which are being made. Here we study two of these decisions which must be made simultaneously, the selection of the most feasible process and material combination for the development of an injection mold. This coupled decision is formulated with the attention directing tool, coupled selection-selection Decision Support Problems. Specifically, a we solve a decision problem to determine the most feasible process and material combination for the production of a simple rib to be produced using a rapidly prototyped injection mold. The resulting mold must be able to withstand the forces, stresses and strains imposed on it in the injection molding process. The emphasis of this paper in on the methods rather than on the results, per se.
Metrics for Evaluating Machining Process Plans
Authors: Hirode Kartheek , Shah Jami J.
Published: February 2021

Selection of the best plan from alternative process plans, and/or plan improvement, requires that we have a set of evaluation metrics. In this paper, we explore the issues related to measures of goodness of process plans at different levels. Several evaluation metrics are proposed such as feasibility, accuracy, consistency, operation-time and setups. These measures can not only help in plan selection but also in pin pointing the flaws in the process plans. Using the proposed metrics, a structured feedback mechanisms and a refinement framework could be developed to arrive at the best process plan. Evaluation is done at the operation and sequence levels, and could be extended to other levels. The measures take into account shapes, sizes, feature relations and all ANSI Y14.5M tolerances in the evaluation of process plans. The proposed measures are also relevant to DFM, since the inability to produce a satisfactory process plan implies difficult to satisfy design specifications.
Design for Machining Over the Internet
Authors: Kim Jae H. , Wang Fu-Chung , Séquin Carlo H. , Wright Paul K.
Published: February 2021

Inspired by MOSIS, the CyberCut project has been developing a manufacturing service for mechanical parts over the Internet. Among the various services provided by CyberCut, this paper will focus on the front end of the design process, in particular on the on-line CAD tool that the designers will be working with when defining the final geometry of a part to be fabricated with 3-axis milling. To date we have constructed two prototype versions of a design interface for CyberCut, called WebCAD, and tested them on audiences consisting mostly of students at Berkeley and at some sister institutions with research groups working on similar problems in design for machining. We learned that it is surprisingly difficult to create such a front end that will lead the designer to manufacturable design on 3-axis milling machine. We will discuss the results of these initial trials, and the insights gained from them, which then led to the specifications for WebCAD 1.5 which is currently nearing completion. We will discuss the simple and consistent view of the milling process that needs to be presented to the users of WebCAD, some of the key paradigms in the user interface, and the extra utilities that we had to incorporate into the WebCAD tool for users who have had no previous exposure to machining.
Practical Passive Assembly: Gripper Design and Assembly Sequence Optimization
Authors: Marehalli Jayavardhan N. , Sturges Robert H.
Published: February 2021

For efficient assembly without feedback systems (or, passive assembly), the assembler should know the ideal orientation of each component and the assembly sequence. A heuristic presented here finds an optimal assembly sequence and prescribes the orientation of the components for a minimum set of grippers — ideally one. The heuristic utilizes an index of difficulty (ID) that quantifies assembly. The ID for each task in the assembly process is computed based on a number of geometrical and operational properties. The objective of the optimization problem here is to minimize the assembly ID and categorize parts/subassemblies based on their preferred direction of assembly while allowing re-orientation of the base part. It is assumed that the preferred direction of assembly is vertically downwards consistent with manual as well as most automatic assembly protocols. Our attempt is to minimize the number of degrees of freedom required in a re-orienting fixture and mathematically derive the requirements for such a fixture. The assembly of a small engine is used as an example in this study due to the variety of ideally rigid parts involved.
Performance of a Shape Deposition Manufacturing Cell
Authors: Pinilla J. Miguel , Prinz Fritz B.
Published: February 2021

As Rapid prototyping processes start delivering production quality parts, the demand for low volume manufacturing is increasing. This paper explores the performance of an SDM cell for volume production of one-of-a-kind parts. The SDM process is modeled from an operations perspective and a queuing network that implements the process simulated. On this simulated cell, a number of scheduling policies are evaluated and their results analyzed for cycle time performance and variability.
Operation Decomposition for Freeform Surface Features in Process Planning
Authors: Sun Ganping , Wang Fu-Chung , Wright Paul , Sequin Carlo
Published: February 2021

Freeform surface features are often machined with multiple operations. The geometry, tools, and cutting parameters of these operations have to be determined during process planning. In this paper, strategies and algorithms to decompose a freeform surface feature into multiple operations, which include roughing (facing and end milling), finishing, tapering, and corner rounding, are presented. For each operation, tool and parameter selections are based on minimizing machining time with the constraints of the specified roughness, tolerance, and machine tool safety. Geometry decompositions are based on the selected tools and the surface slope for the purpose of improving the cutting efficiency. Methods to control the quality requirements (roughness and tolerance) and to estimate the total machining time are also developed. In addition, the manufacturability of freeform surface features is discussed.
Building an Integrated Large Scale Step Database for Virtual Enterprises
Authors: Sun Jianhong , Hardwick Martin
Published: February 2021

The rapid expansion of high performance computer networks such as the Internet allows companies to come together electronically to exploit emerging market conditions and produce new products. Such a group of companies has been called a virtual enterprise (VE). One barrier to VE collaboration is the lack of interoperability among the application systems of different companies — product data produced by the systems at one company cannot be read by the systems at another.

STEP is a state-of-the-art technology for product data exchange and provides a basis for VE data sharing. In this paper, some challenges and difficulties of building an integrated large-scale database of STEP data are discussed. A prototype database was designed and implemented to test our solutions. Preliminary results show that the database is scalable and able to integrate STEP data. We believe the solutions are a basis for building a practical STEP database that can be used to support VE collaboration.
System-Level Robustness Through Integrated Modeling
Authors: Suri Rajiv , Otto Kevin
Published: February 2021

Variation reduction strategies have traditionally focused on treating the output of a single manufacturing operation. In practice, however, manufacturing systems are comprised of multiple operations, each of which can add to or reduce product variation. Additionally, the sensitivity of each operation to input variation is a function of the operating point, which can only be changed in conjunction with the operating points of all other operations in that system. As such, optimizing each operation within a system individually does not guarantee lowest end-of-line variation. What is needed instead is a method for conducting a system-level parameter design in which the operating points of each operation are optimized as a complete set to reduce final product variation. The logistics of such an integrated parameter design scheme make changes or designed experiments on the actual system unwieldy or impossible; instead a system level model can be used. In this paper we use Integrated System Models to conduct system-level parameter design. We demonstrate this technique on a model of a sheet stretch-forming manufacturing system. Through this example, we show that selecting operating points while considering the entire system results in a greater reduction in variation than Taguchi-style robust design conducted independently on each of the operations within the system.
A Proposal of Design Methodology for Upgradable Products
Authors: Umeda Yasushi , Shimomura Yoshiki , Yoshioka Masaharu , Tomiyama Tetsuo
Published: February 2021

One of main causes of the environmental issues is the current mass production paradigm. Developing upgradable products is one of the most hopeful approaches for solving these issues, because they will have longer lives, encourage reuse of artifacts, and therefore, create new business chances at later stages of product life cycles. However, design for upgradability has been hardly discussed.

This paper proposes a design methodology for upgradable products. First, we clarify the definition of design for upgradability by comparing it with other design strategies. Second, by analyzing data of existing series design, we propose several design patterns and two basic guiding principles; namely, making function independent and making function insensitive. Based on these analyses, a design methodology for upgradability is proposed and a prototype of upgrade design support system is illustrated. Finally, feasibility of the methodology is discussed by applying result of an experimental design to the prototype system.
Passive Assembly of Screws: Part 1 — Modeling Screw Threads for Contact Analysis
Authors: Wiedmann Stephen L. , Sturges Robert H.
Published: February 2021

Successful assembly of threaded fasteners by compliant devices, like the SRCC, requires a thorough understanding of all possible contact configurations. In this study, the threaded pair is modeled numerically and contact tests are automated through software manipulation. It is shown that contact types and locations lack symmetry with respect to symmetrical test orientations of the screw.
The Representation of Function in Computer-Based Design
Authors: Szykman Simon , Racz Janusz W. , Sriram Ram D.
Published: February 2021

This paper proposes a standardized representation of function for use by the research community, industry, and eventually commercial software vendors. This includes schemata (information models) for representation of function and associated flows, as well as an initial attempt at developing taxonomies of functions and flows. The objective of the latter effort is to generate taxonomies that are as small as possible, yet generic enough to allow modeling of a broad variety of engineering artifacts. This representation is intended to provide a generic infrastructure that will facilitate the capture and exchange of function information among researchers at present, and eventually in industry by contributing to interoperability between design systems, be they commercial or developed internally within a company.
Toward a Reasoning Framework of Design As Synthesis
Authors: Yoshioka Masaharu , Tomiyama Tetsuo
Published: February 2021

Most of the previous research efforts for design process modeling had such assumptions as “design as problem solving,” “design as decision making,” and “design by analysis,” and did not explicitly address “design as synthesis.” These views lack notion and understanding about synthesis. Compared with analysis, synthesis is less understood and clarified. This paper discusses our fundamental view on synthesis and approach toward a reasoning framework of design as synthesis. To do so, we observe the designer’s activity and formalize knowledge operations in design processes. From the observation, we propose a hypothetical reasoning framework of design based on multiple model-based reasoning. We discuss the implementation strategy for the framework.