Jatinder Madan

Sustainability characterisation for manufacturing processes

Manufacturing industries lack the measurement science and the needed information base to measure and effectively compare environmental performances of manufacturing processes, across resources and associated services with respect to sustainability. The current use of ad hoc methods and tools to assess and describe sustainability of manufactured products does not necessarily account for manufacturing processes explicitly, and hence results in inaccurate and ambiguous comparisons. Such comparisons do not proactively contribute to sustainability improvement. Further, we identified that there are no formal methods for acquiring and exchanging information that help establish a consolidated sustainability information base. Our ultimate goal is to develop the needed measurement science and methodology to evaluate sustainability of fundamental manufacturing processes to ensure reliable and consistent comparisons. As a precursor, based on a literature study, this paper identifies the required elements to evaluate sustainability performance for manufacturing with a focus on the environmental impact. Societal and economic impacts, although equally important, are beyond the scope of discussion in this paper. In this paper, we first discuss identified manufacturing process classifications, sustainable manufacturing indicators and computable metrics, relevant information models and software tools, a conceptual model for sustainability characterisation, and finally, conclude with an overview of the future research directions.

Characterizing Energy Consumption of the Injection Molding Process

ABSTRACT Presently available systems for sustainability assessment do not fully account for aspects related to a product’s manufacturing. In an effort to make more sustainable decisions, today’s industry seeks reliable methods to assess and compare sustainability for manufacturing. As part of the Sustainable Manufacturing program at the National Institute of Standards and Technology (NIST), one of our objectives is to help develop the needed measurement science, standards and methodologies to evaluate and improve sustainability of manufacturing processes. As a first step towards developing standard reference sustainability characterization methodologies for unit manufacturing processes, in this paper we focus on injection molding with energy as the sustainability indicator. We present a science-based guideline to characterize energy consumption for a part manufactured using the injection molding process. Based on the study, we discuss the selection of process parameters and manufacturing resources, determination of cycle time, theoretical minimum energy computations, and estimated energy computations for characterizing the injection molding process.

Characterizing Sustainability for Manufacturing Performance Assessment

Manufacturing industries lack the measurement science and the needed information base to measure and effectively compare performance of manufacturing processes, resources and associated services with respect to sustainability. The current use of ad-hoc methods and tools to assess and describe sustainability of manufactured products do not account for manufacturing processes explicitly and hence results in inaccurate and ambiguous comparisons. Further, there are no formal methods for acquiring and exchanging information that help establish a consolidated sustainability information base. Our goal is to develop the needed measurement science and methodology that will enable manufacturers to evaluate sustainability performance of fundamental manufacturing processes ensuring reliable and consistent comparisons. In this paper, we propose and discuss a methodology for sustainability characterization to bridge the measurement science and the needed information base for sustainable manufacturing. This will set the stage for manufacturers to objectively assess and compare different manufacturing processes for sustainability.Copyright

Die-Casting Feature Recognition for Automated Parting Direction and Parting Line Determination

Determining parting direction and parting line for die-cast parts is a nontrivial task that not only depends upon shape and topology of the part, but also on many process related factors. Normally, a die-casting expert decides parting direction and parting line, intuitively taking into account a large number of factors, and this process can be time consuming and cumbersome in many cases. This study addresses automated determination of parting direction and parting line for a die-cast part from part CAD model. The proposed methodology takes STEP file of the part as input for extracting die-casting features, which consists of protrusion or depression regions of the part. These features are classified into those with single, double, or multiple withdrawal directions. Geometric reasoning is used for feature recognition, which includes nested and interacting features. Global visibility instead of local visibility is used for planning withdrawal direction, which makes the decision arrived by present system closer to industrial practice. Parting line is determined based on selected candidate parting direction considering process constraints and priorities. The contribution of this paper is in terms of development of an automated parting direction and parting line determination system, which is more comprehensive and overcomes limitations of the previous work. Results of this system have been validated with those arrived at by experts from the die-casting industry.

Automated identification of complex undercut features for side-core design for die-casting parts

This article describes automated identification, classification, division and determination of release direction of complex undercut features of die-cast parts. The proposed system uses the concepts of visibility and accessibility to identify undercut features from a B-rep model of a die-casting part. The undercut features are then classified using a rule-based algorithm. Thereafter, the identified complex undercut features are separated into simple ones. Finally, the release direction for each simple undercut feature is determined and those having common release direction are grouped. The proposed system is implemented on case study die-cast parts, and the results are verified. This article would help bridge the design-manufacturing integration gaps in the die-casting process.

System for computer-aided cavity layout design for die-casting dies

Die-casting is one of the methods used to produce a large number of components with a good surface finish by injecting cast alloys into a metal mould under high pressure. The design of a die-casting die requires human expertise and is normally performed by trial and error, which leads to monetary and time losses. Automation at the initial die design stage would result in higher productivity and would reduce the production lead time. Decisions regarding the number of cavities, the layout pattern and the placement of cavities in die-casting are critical for die design and manufacturing. This paper presents research work on a system for computer-aided cavity layout design for die-casting dies. The proposed system consists of three modules: (1) determination of number of cavities; (2) selection of layout pattern; and (3) placement of cavities in the die base. It enables die designers to generate a cavity layout design automatically from a computer-aided design (CAD) file of the part with little information provided manually. The optimal number of cavities is determined by considering economic, technical, geometrical and time limitations, followed by the selection of a layout pattern. Thereafter, cavities are placed in the die base. The developed system depends on a database of die-casting machines and materials along with a knowledge base of die design. This system has been tested on a number of die-casting parts and results have been found to be along the lines of those obtained by the industry. The proposed system is more comprehensive than those presently available and is a step in the right direction for design-manufacturing integration for die-casting.

Computer aided design of gating system for a die-casting die

Design of gating system of a die-casting die is a non-trivial task, which depends on a number of parameters influenced by part design and die-casting alloy. Today, a lot of CAD/CAM tools are used for design, development and manufacturing of die-casting dies. However, design of a die-casting die and its gating system, still depend on a die-casting expert and require lot of time. Present work is about computer-aided design of gating system for die-casting die. System proposed in this paper takes CAD file of the die-casting part as input and uses process knowledge to determine different parameters of the gating system. Design of various components of the gating system, namely runner, gate and overflow is attempted. A feature library is proposed, which together with parametric design, generates CAD model of the components of the gating system. The system would be useful to bridge the gap between design-manufacturing integration for die-casting.

A Computer-Aided System for Sustainability Analysis for the Die-Casting Process

Currently available sustainability analysis systems for the die-casting process primarily depend on the material properties and do not account for process information. As a result they are unable to assess or compare the sustainability of parts made using different process plans. In this paper, we propose a new computer-aided system named Sustainability Analyzer for Die-casting Process. Here, we discuss the details of the architecture and the working of the proposed system. We analyze sustainability using three sustainability indicators, namely energy use, solid waste and carbon emissions. The proposed system is verified by comparing results with the actual data measured from the shop floor. The proposed system is beneficial for sustainability analysis comparing different plans alongside material properties, ultimately helping the die-casting industry to reduce carbon emissions and material waste besides improving energy efficiency.Copyright

Optimal-parting direction selection for die-casting

Parting-direction selection for die-casting parts is an important decision, which affects further downstream activities like manufacturing. Selecting a suitable parting direction in die-casting is difficult as it is influenced by many factors based on shape, topology and manufacturing process. Normally it is decided by die-casting experts. There is still no qualitative or quantitative method that considers all influencing factors. A comprehensive methodology to identify optimal parting direction for die-casting has been developed. Candidate parting directions are evaluated using Pahl and Beitz method. Comparison of results for many parts, with those obtained from industry has been found to be satisfactory.