A Case Study in Extended Value Engineering

Extended value engineering techniques provide an efficient, systematic approach to expose unnecessary costs, spur innovation, and direct efforts toward product and process improvement. Extended value engineering involves the comprehensive application of function diagramming, cost/cycle analysis, process diagramming, and competitive cost comparison. The application of these techniques to a mining equipment manufacturer, specifically to an ore haulage vehicle, is described in terms of cost reduction and manufacturing process improvement.

Forging a Geometric Link Between Function-Based Design and DfM

Design for Manufacture (DfM) tends to explore only a small space of possible designs toward improving manufacturability. By focusing primarily on detailed geometry, DfM tends to recommend incremental changes. This paper presents a methodology that begins at the conceptual design stage, applying functional modeling to the generation of design configurations. These functional abstractions are merged with real part geometry toward generating potentially manufacturable design skeletons. The direct connection from function to manufacturable form afforded by this method allows the designer to make better-informed design decisions at the earliest stages of the design process.

Simplified Method of Calculating Assembly Time

This paper presents a simplified method for functional evaluation of parts and subsequent combination and elimination of parts with redundant and unnecessary functions. The method uses a simple spreadsheet-based tool that has proven to be an effective aid during design review and brainstorming sessions. Also presented is a simple method of initial assessment of manual assembly times. The assessment is performed by taking into account basic factors influencing part recognition, handling, manual assembly workspace and putting the parts together. Usefulness of both tools has been initially tested on a wide range of assembly configurations, from a variety of simple consumer goods to aerospace components. Both tools can also be presented as checklists thus having a ready-to-use cookbook appearance, which was particularly valued by manufacturing engineers making quick on-the-floor assessments.

Modeling of Wrinkles and Its Application in Footwear Design

We develop a parametric description of a wrinkle as a shape feature that may be superposed upon selected regions of a 3D surface defined by B-splines or NURBS. We show the use of such a feature in footwear design. We found that the shape modification operator for such a feature can be developed using geodesic offsets. A computer program has been implemented providing such a feature, and some examples of the output of the program are presented in this paper. We also address the need for automatically generating 2D surface developments of 3D shapes with superposed wrinkles. A finite-element style iterative algorithm is outlined for the performing this task; a new distortion energy model is developed for this algorithm in this paper.

Design for Disassembly and the Value of Robotic Semi-Destructive Disassembly

This article explores robotic semi-destructive disassembly’s relationship with design for disassembly, and the article investigates its value as a disassembly approach for remanufacture and / or recycling. Specifically, the compatibility of design for disassembly guidelines with semi-destructive disassembly is explored. Regulatory pressures, recovering the value of products’ materials and the long-range environmental importance of cycling material flows motivate the exploration. The article compares general design for disassembly guidelines drawn from the literature with experimental results from the semi-destructive disassembly of a simple consumer product. Additionally, the value of semi-destructive disassembly is investigated. The prevailing view of semi-destructive disassembly’s value is discussed, and the realities of an experimental semi-destructive disassembly study are contrasted with these beliefs.

RPBloX Rapid Prototyping: More Than Just Layers

Rapid Prototyping and Manufacturing (RP&M) technologies are increasingly being applied to produce functional prototypes and directly manufacture small batches of components (where the “prototype” is itself the final product). Although there are various forms of RP&M, almost all rely on a layered manufacturing approach. However despite the flexibility of these systems, they have common drawbacks such as slow build rates, a limited number of build axes (typically one) and the need for post processing, i.e. removal of support structures and finishing. This paper reports the preliminary research that aims to combine sophisticated CAM software and automated assembly technologies to demonstrate that a non-layered method of RP can be engineered. The system under development is referred to as RPBloX. This novel technique has the potential to not only supplement current RP techniques but also act as a standalone method in which products can be brought to market within a shorter design-manufacture cycle time. Essentially, the RPBloX methodology involves a cellular approach to building up a part. Rather than slicing up the CAD model into numerous thin sheets, RPBloX segments the model into 3D cells (or Bloxes) of varying sizes. In contrast to current RP technology, conventional machine tools such as CNC machines and robots are employed for manufacturing and assembly work. Consequently, production costs could be significantly reduced without the forfeiting accuracy and timeliness.

Observations on Raytheon 6 σ: The ASTOR Early Engagement

Raytheon Six Sigma (R6Sigma) is a six-step quality management approach and culture change effort that has proven to be highly effective. It incorporates lessons learned from the earlier efforts by Motorola, Texas Instruments, Allied Signal, General Electric, and many others. Within each of these major companies, the Six Sigma approach is a reflection of the company’s unique culture and specific industry needs. However, one criticism common to most of these programs is that the change analysis and leadership tools are engaged too late in the overall process. Building upon the lessons learned by other organizations, the paper recounts the early engagement of the Six Sigma tools, coupled with direct customer involvement, on a large-scale program by the Raytheon Company: The Airborne Stand-off Radar (ASTOR) system, which is under development for the UK Ministry of Defense (MOD). Because the ASTOR program is still years from completion, this paper cannot provide detail in terms of final lessons learned or quantified results derived from the front-end application of R6Sigma on this program. The purpose of this paper is to capture the thought processes behind (and initial stages observed during) early customer involvement and the application of R6Sigma process improvement approaches at the beginning of the program.

Accessibility Driven Spatial Partitioning for Generating Sacrificial Multi-Piece Molds

This paper describes an algorithm based on accessibility-driven partitioning approach to the design of sacrificial multi-piece molds. We construct gross shape of the mold by subtracting the part model from the mold enclosure and analyze its accessibility. The gross mold shape is partitioned using accessibility information. Each partitioning improves accessibility and we produce a set of mold components that are accessible and therefore can be produced using milling and drilling operations. Our approach has the following advantages. First, by using multi-piece molds we can create geometrically complex objects that are impossible to create using traditional two-piece molds. Second, we make use of sacrificial molds. Therefore, using multi-piece sacrificial molds, we can create parts that pose disassembly problems for permanent molds. Third, mold design steps are significantly automated in our methodology. Therefore, we can create the functional part from the CAD model of the part in a matter of hours and so our approach can be used in small batch manufacturing environments.

A Feature-Based Approach for Representing Composite Components

The progress with which composite materials are being used in industry has been staggering. The methods, processes and procedures of developing and manufacturing composite materials have always been the center stage for the composite materials research and applications. While feature technologies, in particular feature-based design, have been widely practiced by many in the areas of designing and manufacturing conventional materials, one has not yet seen it help to reap the benefits for composite materials manufacturing. This paper proposed a feature-based approach for representing composite components. Two types of features have been defined, structural and geometrical. Based on the suggested approach toward representing features on a composite component, a concurrent engineering kernel is being developed, in which design and manufacturing of composite manufacturing come together seamlessly to enable a complete product development environment for composite material design and manufacturing.

Tolerance Specification for Cost Reduction

The paper presents a novel optimal tolerance specification technique to minimize product cost. By introducing the properties of order statistics and the theory of tolerance limit to the traditional simulation method, a n dimensional tolerance search problem is transformed into a two dimensional one. The established tolerance limit inference method has the advantages of high efficiency for computation, robust for any distribution, and guaranteed confidence level compared with other tolerance specification methods. In addition, to obtain the optimal product cost, unlike most cost analysis models, the production yield level in the analysis is treated as an optimal variable instead of a constant. The approach is demonstrated by examples.