Concurrent engineering: Automation, tools, and techniques

As products become ever more diversified, their life cycles are becoming shorter. To reduce production costs, increased process automation and concurrent design are priorities. Therefore, a collaborative integrated design system is crucial in the mold design and manufacturing process. This research develops a collaborative navigation system for concurrent mold design within the computer-aided design (CAD) browser, using Pro/Web.Link as the core tool. Providing both concurrent engineering and collaborative design functions, the navigation system is capable of assisting designers in accomplishing 3D mold development efficiently and accurately with the help of the standard component library and design decision-making system. The results show significant time savings over other mold design process methodologies.

An Internet-enabled integrated system for co-design and concurrent engineering

This paper presents ongoing work to standardize model-based system engineering as a complement to point design development in the conceptual design phase of deep space missions. It summarizes two first steps towards practical application of this capability within the framework of concurrent engineering design teams and their customers. The first step is standard generation of system sensitivities models as the output of concurrent engineering design sessions, representing the local trade space around a point design. A review of the chosen model development process, and the results of three case study examples, demonstrate that a simple update to the concurrent engineering design process can easily capture sensitivities to key requirements. It can serve as a valuable tool to analyze design drivers and uncover breakpoints in the design. The second step is development of rough-order- of-magnitude, broad-range-of-validity design models for rapid exploration of the trade space, before selection of a point design. At least one case study demonstrated the feasibility to generate such models in a concurrent engineering session. The experiment indicated that such a capability could yield valid system-level conclusions for a trade space composed of understood elements. Ongoing efforts are assessing the practicality of developing end-to-end system-level design models for use before even convening the first concurrent engineering session, starting with modeling an end-to-end Mars architecture.

An integrated graphical user interface (GUI) for concurrent engineering design of mechanical parts

This research focuses on the development of a quantitative intelligent system for implementing concurrent engineering design. The paper first discusses the task of concurrent engineering design and the basic requirements for conducting integrated concurrent engineering design. The proposed quantitative intelligent system approach combines qualitative reasoning, based upon design and manufacturing knowledge, and quantitative evaluation and optimization, conducted using design information and manufacturing data generated in the knowledge-based reasoning. The method allows considerations on non-operating principle aspects of a product to be incorporated into the design phase, such as manufacturing, maintenance, service, recycle, etc., with an emphasis on production costs. The proposed method serves as a convenient software tool for gathering information required in the concurrent engineering design process and integrates tasks from different parts of the product development life cycle, particularly function design, manufacturability analysis and production cost estimation. A prototype software system is developed based upon this method using Smalltalk-80. In the prototype system, concurrent engineering design is carried out by: (1) describing and representing design requirements; (2) generating feasible design candidates and evaluating their design functions; (3) representing design geometry; (4) finding the associated production processes and predicting the production costs of each feasible design; and (5) identifying the costeffective design that satisfies given design requirements and requires minimum production costs.

The rapid response to the requirements of customers and markets promotes the concurrent engineering (CE) technique in product and process design. The decision making for process quality target, SPC method, sampling plan, and control chart parameter design can be done at the stage of process quality plan based on historical data and process knowledge database. Therefore, it is a reasonable trend to introduce the concepts and achievements on process quality evaluation and process capability analysis, CE, and SPC techniques into process plan and tolerance design. A new systematic method for concurrent design of process quality, statistical tolerance (ST), and control chart is presented based on a NSFC research program. A set of standardized process quality indices (PQIs) for variables is introduced for meeting the measurement and evaluation to process yield, process centering, and quality loss. This index system that has relatively strong compatibility and adaptability is based on raisonne grading by using the series of preferred numbers and arithmetical progression. The expected process quality based on this system can be assured by a standardized interface between PQIs and SPC, that is, quality-oriented statistical tolerance zone. A quality-oriented ST and SPC approach that quantitatively specifies what a desired process is and how to assure it will realize the optimal control for a process toward a predetermined quality target.

North American undergraduate mechanical engineering design education has failed to meet the needs of industry in educating students in effective design philosophies typified by the concurrent engineering design philosophy. Current programmes emphasize traditional engineering analysis courses, leaving little room for truly educating the students in the fundamentals of mechanical engineering design. This paper uses the concurrent engineering design paradigm to design a programme for the education of students in mechanical engineering design. The basics of concurrent engineering design are outlined, the failings of typical design education stated, and an exploration of the required features of a new design curriculum presented.

In this paper, we apply Taguchi Methods in the framework of concurrent engineering design for robot-based manufacturing sys tems to obtain higher accuracy and repeatability for robot end-effectors. It is well known that the configurations of robot end-effectors in workspace will affect the accuracy and repeatability Taguchi Methods are employed to find the configuration and location within which the accuracy and repeatability are the best. The optimal position with higher accuracy and repeatability is determined by using the signal-to- noise ratios (S/N ratios), which are defined according to the "smaller-the-better" characteristics of Taguchi Methods to measure the accu racy and repeatability The results match well with the theoretical analysis of the repeatability and accuracy of the end-effector based on the kinematic relationship. In addition, we also study the random and systematic errors due to joint uncertainties and examine their effects on the accuracy and repeatability. The analysis using S/N ratios yields results that are consistent with expectation. The results demonstrate that Taguchi Methods and S/N ratios are very useful tools in design for accuracy and repeatability of robotic end-effectors. The sensitivity and consistency of accuracy with respect to the tolerance of joint angles are represented by 3D surfaces. The tolerance design is per formed, using the sensitivity analysis, to satisfy requirements stipulated by design criteria One of the significant results of consistency analysis is the "threshold" value of tolerance for concurrent engineering design considerations. Simulation results show that the consistency of accuracy and repeatability will be increased dramatically once the tolerance is below such a threshold Both sensitivity and consistency analysis are shown to be important in tolerance design for achieving the desired accuracy and repeatability and for enhancing quality.

Total quality tolerance (TQT) has been widely recognised as a strategic weapon for improving manufacturing performance. The evaluation of quality tolerance efficiency can assist factories in improving their operations across a variety of dimensions. Effective benchmark of high performance in tolerance design, dimension analysis, machinability and assemblability are identified for improving the quality tolerance in manufacturing units. In this paper, drive shaft assembly is considered which is adopted from literature and finding the overall quality tolerance through neuro-fuzzy flow diagram method for different level with minimum inputs are analysed in different fuzzification range values to get optimisation in overall quality tolerance. The characteristics of neuro-fuzzy, multi-stage evaluation and decision making in concurrent product design process are also analysed and a decision support system for tolerance design in concurrent engineering is presented.

Re-engineering of the design process for concurrent engineering

Computer Aided Engineering tools and technologies that hold the potential for creating a simulation based Concurrent Engineering environment in the near-term and a design optimization based capability for the future are analyzed. Technical challenges and opportunities associated with integrating these tools into a software environment that can support multidisciplinary engineering teams are defined and illustrated. A road map for evolutionary creation of a simulation based Concurrent Engineering design environment in the near-term and a design optimization environment in the longer term is presented. Projects underway to create the capability advocated by the road map are presented, to illustrate technical considerations peculiar to Concurrent Engineering of mechanical systems and challenges associated with network based multidisciplinary CAE system integration for Concurrent Engineering.

One method of speeding up traditional engineering activities is by introducing parallel development paths. Although cycle time is reduced, coordination and project documentation become more difficult and are further exacerbated by synchronous collaboration. These needs can be addressed by capturing, accessing, and reusing knowledge consisting of the design, together with its rationale and development history. Successful capturing of design knowledge includes these elements and answers to several questions: What is the design? How was the design achieved? Why were choices made? The paper describes how to capture the history of the informal phase of the specification and design process using the Collaborative Environment for Concurrent Engineering Design (CECED). >

7. Concurrent engineering and collaborative design

CONCURRENT ENGINEERING APPROACH TO FMS DESIGN USING A BLACKBOARD ARCHITECTURE

Concurrent engineering, the practice of simultaneously designing a product and its manufacturing system, is generally viewed as a major source of Japanese competitive advantage (Clark & Fujimoto, 1991). U.S. companies have rushed to construct structured design processes and multifunctional, often colocated teams in order to compete (Nevins & Whitney, 1989). Ironically, however, we discovered in our research that most managers at Japanese auto companies are fairly new to concurrent engineering, which many regard as a Toyota invention. Equally paradoxical, our research found that managers at Toyota, which has long experience with concurrent engineering, made little use of many commonly touted “crucial elements” of successful concurrent engineering. Toyota uses neither colocated nor dedicated multidisciplinary teams, and significant portions of the development process remain relatively unstructured.