Using Ecosystem Landscape Models to Investigate Industrial Environmental Impacts

This article explores the use of ecosystem landscape models to estimate the environmental impacts of industrial activities at the regional / local scale. Integrated ecosystem and industrial modeling is first introduced within the context of life cycle assessment. Then, the use of integrated modeling to overcome problems stemming from the lumped parameter, static, site non-specific nature of life cycle assessment is discussed. Finally, the results of linking a handful of industrially relevant material and information flows demonstrate the ability of current ecosystem landscape models to respond to industrial burdens and estimate some environmental impacts.

Exploration of Local Blade Motions During Blade Shaping for Thick Layered Foam Cutting

The FF-TLOM (Free Form Thick Layered Object Manufacturing) technology is a Rapid Prototyping process based on flexible blade cutting of polystyrene foam. The heated blade is shaped by three parameters, which allows an infinite amount of minimum strain energy blade shapes with none, one or two inflexions. In the shaping domain stable and unstable blade shapes can exist. Stable shapes are defined as curves with none and one-inflexion and are applied for operational cutting of foam layers with the FF-TLOM technology. The tool motions are generated from the static tool poses and are calculated for a linear change of the flexible blade, when the cutting tool moves from one tool position to the next. The cutting blade is positioned to the foam slab with help of a point relative positioned on the flexible blade. The tool frame is positioned with a point fixed relatively to the tool frame. During the tool motions the blade curvature is changed and will introduce a shift of the half way point fixed on the blade (especially in the case of asymmetrical support inclinations and high curvature). Next the local displacement of the blade points in the bending plane of the blade due to blade shaping and tool pitching are quantified during the tool motions. These displacements induce an angle of attack of the blade in cutting direction, and will influence cutting speed and cutting accuracy. The quantification software is developed and will be used in the future for an overall prediction of the total tool curve displacements due to blade shaping, such as roll, pitch, yaw and linear positioning motions of the tool. A general rule for FF-TLOM cutting is minimization of all tool motions, which are not related to the forward cutting motion.

A Methodology for Integrating Welding in DFA

A design for assembly worksheet is introduced that enables flexible accounting of assembly activities, especially welding. Welding activity is broken down into a variety of pre- and post-welding activities and the time penalty is estimated. This weld estimate is included into the traditional worksheet. This approach is especially useful for large complex products that are produced in small volumes where a significant portion of the assembly activity is through welding. These types of products often pose challenges for employing DFMA techniques cost effectively because of the increased engineering cost, divided among relatively few products, outweighs the potential benefits.

Structured Approach to Dimensioning and Tolerancing: A Comprehensive Solution Strategy

This paper is the second of two in which a methodology is presented that provides a structured way of solving Dimensioning and Tolerancing (D&T) problems on new product design. In the previous paper, a methodology was developed for representing the D&T problems of a product in a matrix form known as a Dimensional Requirements/Dimensions (DR/D) matrix. In this paper a comprehensive strategy is presented for determining the values of dimensions and tolerances by satisfying all the relationships represented in DR/D matrix. The comprehensive strategy presented here includes: strategy for separating D&T problems into groups, for determining an optimum solution order for coupled functional equations and tolerance allocation strategies for solving different types of D&T problems. A number of commonly used cost minimization strategies such as the use of standard parts, preferred sizes, preferred fits, and preferred tolerances have also been incorporated into the proposed methodology. The methodology is interactive and suitable for use in a Concurrent Engineering environment.