Browsing by Author "Das, Diganta"
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Item Automated Manufacturability Analysis: A Survey(1995) Das, Diganta; Gupta, Satyandra K.; Regli, W.C.; Nau, Dana S.; ISRIn the marketplace of the 21st century, there is no place for traditional ``over-the-wall'' communications between design and manufacturing. In order to ``design it right the very first time,'' designers must ensure that their products are both functional and easy to manufacture. Software tools have had some successes in reducing the barriers between design and manufacturing. Manufacturability analysis systems are emerging as one such tool---enabling identification of potential manufacturing problems during the design phase and providing suggestions to designers on how to eliminate them.In this paper, we provide a survey of current state of the art in automated manufacturability analysis. We present the historical context in which this area has emerged and outline characteristics to compare and classify various systems. We describe the two dominant approaches to automated manufacturability analysis and overview representative systems based on their application domain. We describe support tools that enhance the effectiveness of manufacturability analysis systems. Finally, we attempt to expose some of the existing research challenges and future directions.
Item Compromised Additive Manufacturing Supply Chain Workshop Report(University of Maryland, 2021-06-16) Sandborn, Peter; Lucyshyn, William; Boyd, Marcus; Das, Diganta; Akhavantaheri, Hirbod; Hedberg, Thomas JrThe potential widespread adoption of additive manufacturing (AM) technology represents a marked shift in the production value chain. This shift represents a transition from value residing within the physical parts and structures, built from traditional designs and fabricated using conventional manufacturing to systems and components produced via additive manufacturing processes, wherein the value resides in the digital technical designs themselves, e.g., technical data packages (TDPs). While the ability to produce parts and structures anywhere there are appropriate facilities and personnel provides great flexibility in the production process, the increasing reliance on digital data creates new challenges and complications (and new opportunities for malicious actors). Breaches of the data systems exchanging proprietary technical data packages enable anyone with access to the data and the appropriate equipment, to manufacture copies of the proprietary parts or structures and steal the intellectual property associated with the data package. Moreover, with the advent of affordable laser scanners, parts can be more readily reverse engineered to replicate the geometry (form & fit), but not necessarily function. These compromised parts could, in turn, be introduced into the supply chain, either for financial gain or other malicious purposes, without the requisite production controls (materials and processes), testing, evaluation, and qualification, leading to potential safety and liability issues. This Workshop focused on the unique issues posed by compromised AM parts and components and how they can be mitigated.Item Current Trends and Future Challenges in Automated Manufacturability Analysis(1995) Gupta, Satyandra K.; Das, Diganta; Regli, W.C.; Nau, Dana S.; ISRIn the marketplace of the 21st century, there is no place for traditional communications between design and manufacturing. In order to ``design it right the first time,'' designers must ensure that their products are both functional and easy to manufacture. Software tools have had some successes in reducing the barriers between design and manufacturing. Manufacturability analysis systems are emerging as one such tool---enabling identification of potential manufacturing problems during the design phase and providing suggestions to designers on how to eliminate them.In this paper, we survey of current state of the art in automated manufacturability analysis. We describe the two dominant approaches to automated manufacturability analysis and overview representative systems based on their application domain. Finally, we attempt to expose some of the existing research challenges and future directions.
Item Enterprise Network Models for Counterfeit Part Supply Chains Workshop Report(University of Maryland, 2021-08-05) Sandborn, Peter; Lucyshyn, William; Boyd, Marcus; Das, Diganta; Akhavantaheri, Hirbod; Hedberg, Thomas JrCounterfeit electronic products have been a reality for many years. Nearly all of the treatment of this problem to date has focused on the detection of counterfeits, which is necessary, but a purely defensive step. Without a network model of the supply chain, disruptions can be haphazard and inadequately targeted. A network model that includes business strategies of distributors of obsolete parts, the ability of laboratories to detect counterfeit parts, impacts of buyback, and return policies is needed. The implications of enforcement (e.g., administrative, legal, or reputational) of anti-counterfeiting policies and the levels of penalties for supplying and accepting counterfeit parts also need to be accommodated in network models. The objective of the workshop is to examine enterprise network modeling as a tool for understanding and disrupting counterfeit electronics supply chains. Participants in the workshop included electronics supply-chain members from OCMs to users, supply-chain monitoring technology developers, academics, policymakers, legal and law enforcement, and other stakeholders.Item Estimation of Setup Time for Machined Parts: Accounting for Work-Holding Constraints(1995) Das, Diganta; Gupta, Satyandra K.; Nau, Dana S.; ISRFor machined parts, setup time is a major component of the total time required to create a machined part. If the setup time can be reduced, this will not only decrease the machining time, but will also ensure better machining accuracy, require fewer work- holding devices and increase machine usage time.To achieve any improvement in setup time, first we need to estimate the setup time accurately. In this paper we propose a methodology to estimate the setup time for machining prismatic parts in a three axis vertical machining center. We consider three major factors in estimating the number of setups, namely---the precedence constraints among machining operations, the feasibility of work holding using vise clamping, and the availability of datum faces for locating the workpiece.
Item Failure Modes, Mechanisms, Effects, and Criticality Analysis of Ceramic Anodes of Solid Oxide Fuel Cells(MDPI, 2018-11-15) Patel, Nripendra K.; Bishop, Sean R.; Utter, Robert G.; Das, Diganta; Pecht, MichaelSolid oxide fuel cells (SOFCs) are a highly efficient chemical to electrical energy conversion devices that have potential in a global energy strategy. The wide adoption of SOFCs is currently limited by cost and concerns about cell durability. Improved understanding of their degradation modes and mechanisms combined with reduction–oxidation stable anodes via all-ceramic-anode cell technology are expected to lead to durability improvements, while economies of scale for production will mitigate cost of commercialization. This paper presents an Ishikawa analysis and a failure modes, mechanisms, effects, and criticality analysis (FMMECA) for all-ceramic anode based SOFCs. FMMECA takes into account the life cycle conditions, multiple failure mechanisms, and their potential effects on fuel-cell health and safety.Item Generating Redesign Suggestions to Reduce Setup Cost: A Step towards Automated Redesign(1995) Das, Diganta; Gupta, Satyandra K.; Nau, Dana S.; ISRAll mechanical designs pass through a series of formal and informal redesign steps, involving the analysis of functionality, manufacturability, cost and other life-cycle factors. The speed and efficacy of these steps has a major influence on the lead time of the product from conceptualization to launching. In this paper we propose a methodology for automatically generating redesign suggestions for reducing setup costs for machined parts.Given an interpretation of the design as a collection of machinable features, our approach is to generate alternate machining features by making geometric changes to the original features, and add them to the feature set of the original part to create an extended feature set. The designer may provide restrictions on the design indicating the type and extent of modifications allowed on certain faces and volumes, in which case all redesign suggestions generated by our approach honor those restrictions.
By taking combinations of features from the extended feature set generated above, we can generate modified versions of the original design that still satisfy the designer's intent. By considering precedence constraints and approach directions for the machining operations as well as simple fixturability constraints, we can estimate the setup time that will be required for each design. Any modified design whose setup time is less than that of the original design can be presented to the designer as a possible way to modify the original design.
Item Intersections of Illicit Trafficking and Counterfeit Parts Workshop Report(University of Maryland, 2021-10-28) Sandborn, Peter; Lucyshyn, William; Boyd, Marcus; Das, Diganta; Akhavantaheri, Hirbod; Hedberg, Thomas JrThe project that sponsored this workshop focuses on the disruption of the supply chains for counterfeit hardware used in critical systems. “Critical systems,” in the context of this project are defined as systems associated with human safety (e.g. transportation, medical), the delivery of critical services (infrastructure, energy generation), important humanitarian and military missions, and global economic stability. These systems are costly to procure, are generally expected to have a long service life, and as a result, they must be supported for long periods of time. However, counterfeit parts are only a single thread of a larger illicit trafficking tapestry. While the world’s largest firms have cracked down on illicit and illegal labor practices, illicit and illegal labor remains a key part of innumerable supply chains. Narcotics production is a hazardous criminal enterprise, but increased professionalization and the availability of quality parts and chemical precursors from China have allowed narcotrafficking cartels to manufacture massive quantities of fentanyl. Weapons traffickers and criminal entities now use additive manufacturing for weapons development and modification. Trafficking of wildlife, agricultural products, and animal parts present various serious concerns including the introduction of invasive species to the spread, and novel development, of viruses. Often, these differing types of criminal behavior are siloed, but as transnational criminal entities continue to replicate neoliberal business practices, they are agglomerating into polycrime entities. These polycrime entities bridge different lines of the trafficking business. Humans are trafficked for forced or illegal labor. People have been trafficked and forced to serve as caretakers of illegal cannabis plants. Mexican drug cartels have purchased 3D printers and hired engineers to develop weapons modifications, uparmor vehicles, and developed manufacturing techniques that increase the potency of various narcotics. This workshop sought to bring together social scientists, engineers, law enforcement, policymakers, and industry to push us out of our comfort zones to build connections and identify gaps. Individual sessions focused on modalities of trafficking: arms trafficking and construction, wildlife trafficking, labor trafficking, and narcotics manufacturing and trafficking.Item Reducing Setup Cost by Automated Generation of Redesign Suggestions(1994) Das, Diganta; Gupta, Satyandra K.; Nau, Dana S.; ISRAll mechanical designs pass through a series of formal and informal redesign steps, involving the analysis of functionality, manufacturability, cost and other life-cycle factors. The speed and efficacy of these steps has a major influence on the lead time of the product from conceptualization to launching.In this paper we propose a methodology for automatically generating redesign suggestions for reducing setup costs for machined parts. Our approach is based on interpreting the design as a collection of machinable features. Our methodology generates alternate machining features by making geometric changes to the part, and adds them to the feature set of the original part. The designer may provide, restrictions indicating that certain surfaces and volumes should not be changed, in which case all redesign suggestions generated by our approach honor those restrictions. Using features from the extended feature set generated above, one or more new designs may be found that need fewer setups than the original part.
Item The Distribution and Detection Issues of Counterfeit Lithium-Ion Batteries(MDPI, 2022-05-21) Lingxi, Kong; Das, Diganta; Pecht, Michael G.This paper presents the various ways that lithium-ion batteries are being counterfeited, the problems that counterfeit batteries present, how they enter the consumer market, and the difficulties of detection. Simple external visual inspection of the battery is unreliable. As shown in the presented case study, even for the same brand batteries, their internal structures are different. The current counterfeit prevention methods focus on the manufacturing step. To reduce the risk of counterfeit batteries, device manufacturers and retail stores should characterize the batteries they receive. In addition, related authorities or organizations should set standards to enable a universal battery tracking method along the supply chain to prevent counterfeit lithium-ion batteries from entering the market.