A Hybrid Intelligent System for Stamping Process Planning in Progressive Die Design

This paper presents an intelligent, hybrid system for stamping process planning in progressive die design. The system combines the flexibility of blackboard architecture with case-based reasoning. The hybrid system has the advantage that it can use past knowledge and experience for case-based reasoning when it exists, and other reasoning approaches when it doesn’t exist. A prototype system has been implemented in CLIPS and interfaced with Solid Edge CAD system. An example is included to demonstrate the approach.Singapore-MIT Alliance (SMA

A Study on the Boundary Conditions of 90° Paper Pop-up Structures

The design of a pop-up book or card has hitherto been labour intensive with tasks of trials and errors. The constructions of collapsible pop-up structures can be demanding and inefficient without adequate knowledge of their geometric properties. This paper examines the properties of creases in 90° pop-up structures. A 90° pop-up structure is one that erects fully when two adjacent base pages, on which it sits, are opened to a right angle. In particular, we define a boundary region for creating 90° pop-ups. Similarly, paper folds are able to achieve pop-up effects and can be integrated with 90° pop-up constructions. The development of these pop-up structures can be represented graphically. Through this study, a fundamental foundation for pop-up topology and geometry is built. This foundation would be vital for understanding the applications of pop-up making techniques. The mathematical relationships devised would be useful for developing computer-enhanced pop-up design.Singapore-MIT Alliance (SMA

Functional Modeling in Conceptual Die Design

The use of function has been recognized as an important part of the design process over last two decades, especially at the conceptual design stage, due to its critical role in determining the final product’s functionality. Although there are now some general methodologies dealing with functions or reasoning about functions, virtually no commercial CAD system can support conceptual design process due to their focus on geometrical modeling but not functional modeling. This paper presents a functional modeling approach to guide conceptual die design through functional reasoning steps including functional decomposition, functional supportive synthesis and function-structure mapping. The formed functional model provides a good basis to generate various die structures at the conceptual design stage, because function is a higher level of abstraction than structure, and helps to capture the designer’s intent. The functional modeling process has been implemented in a computerized design environment to expedite the conceptual die design process.Singapore-MIT Alliance (SMA

Building a Document Corpus for Manufacturing Knowledge Retrieval

When faced with challenging technical problems, R&D personnel would often turn to technical papers to seek inspiration for a solution. The building of a corpus of such papers and the easy retrieval of relevant papers by the user in his query is an area that has not been systematically dealt with. This is an attempt to build such a corpus for manufacturing R&D personnel. Manufacturing Corpus Version 1 (MCV1) is an archive of more than 1400 relevant manufacturing engineering papers between 1998 and 2000. In this paper, the origins and motivation of building MCV1 is discussed. The innovative coding process which is specially designed for manufacturing companies will be presented. All other relevant issues, like coding policy, category codes and input documents, will be explained. Finally, two quality indicators which integrate all concerns about coding quality will be examined.Singapore-MIT Alliance (SMA

Framework to Manage Customer Enquiries for SMEs

For most Smaller Manufacturing Enterprises (SMEs), how to manage customer enquiries at the customer enquiry stage is of great importance to maintain the competitive advantage and secure future customer orders. A lack of co-ordination between marketing/sales and production at this stage often leads to confirmed orders being delivered later than promised and/or being produced at a loss. In the paper, the problems and the solutions for managing customer enquiries faced by many SMEs are addressed. A general process for dealing with customer enquiries at the customer enquiry stage and a corresponding DSS approach are presented in detailed. The SMEs would benefit from the proposed DSS in which the considerations of current material and production capacity are given to the customer enquiry management process.Singapore-MIT Alliance (SMA

Experimental Study on the Demolding Force in Micro Metal Injection Molding

In this paper experimental study on the demolding force needed to eject micro structures in Micro Metal Injection Molding (μMIM) is conducted. Injection molding is done on a variotherm mold mounted on a Battenfeld injection molding machine and demolding force measurement is done on an Instron tensile testing machine. Green part is a round disc of φ16 mm and thickness 1.5 mm with an array of φ100 μm × height 200 μm micro structures at the center. The experimental results are in good accordance with the previous analysis results.Singapore-MIT Alliance (SMA

DSS Model for Profit Maximization at Customer Enquiry Evaluation Stage

This paper presents an optimal method and a heuristic approach which aims at maximizing the profit when responding to a set of customer enquiries under limited capacity. The model takes into consideration the quantity of available-to-promise (ATP) which measures the capability to fill customer orders, along with enquiry quantity and product price. The optimal method and the heuristic approach are tested using ATP, product price and enquiry quantity each at their different levels. From the example conducted, it is found that (1) the optimal model can help to make appropriate decision for selecting a subset of enquiries, and (2) the heuristic approach can produce a result within 5% from the optimum achieved by optimal method for most parameter settings.Singapore-MIT Alliance (SMA

Functional design of mechanical products based on behavior-driven function-environment-structure modeling framework

The relative significance of upstream design activity to downstream design activity is widely recognized, due to its critical role in determining the final product’s functionality. Although there are now some general methodologies dealing with functions or reasoning about functions, virtually no commercial CAD system can support functional design. In functional modeling, a design problem is represented in a hierarchy of functions and the behaviors that realize the functions. This paper presents a functional design methodology based on a behavior-driven function-environment-structure (B-FES) modeling framework to guide functional design through functional reasoning steps including causal behavioral reasoning (CBR) and functional decomposition. The proposed functional design starts from a set of design specifications including functional requirements and design constraints, and results in diverse behavioral schema corresponding to a set of design alternatives. A design example for functional design of a terminal cut-off unit in an automatic assembly system is used to provide a demonstration of the proposed functional design methodology.Singapore-MIT Alliance (SMA

Fulfillment of Rush Customer Orders under Limited Capacity

Customer demand fulfillment is the business process within a company that determines how the customer demand is fulfilled. A rush order is the last minute customer order after the production plan of a company has been concluded. For these rush orders, appropriate and reasonable response is imperative as it could put strain on customer relationship and services. A good and positive response could help the company to build and retain its market share in today’s highly competitive markets. A model aims at decreasing the product inventory cost is proposed in this paper. In this model, the prioritized fulfillment sequence of rush customer demands can be searched in terms of the product inventory cost. The paper focuses on two main issues: the available-to-promise (ATP) based fulfillment ability and the prioritized fulfillment of customer demands. For ATP based fulfillment, a dynamic bill-of-material (BOM) is proposed to handle the complicated issues of BOM, BOM explosion and production capacity. By means of dynamic BOM, material availability as well as production capacity can be taken into consideration simultaneously and efficiently. Two methods, mathematical optimization and heuristic algorithm, are constructed and elaborated on in the second issue. The proposed model allows companies to prioritize customer rush orders in terms of product inventory cost.Singapore-MIT Alliance (SMA

PVC-LOT-008-J-038

Laser-based powder-bed fusion additive manufacturing or three-dimensional printing technology has gained tremendous attention due to its controllable, digital, and automated manufacturing process, which can afford a refined microstructure and superior strength. However, it is a major challenge to additively manufacture metal parts with satisfactory ductility and toughness. Here we report a novel selective laser melting process to simultaneously enhance the strength and ductility of stainless steel 316L by in-process engineering its microstructure into a crystallographic texture. We find that the tensile strength and ductility of SLM-built stainless steel 316L samples could be enhanced by ~16% and ~40% respectively, with the engineered textured microstructure compared to the common textured microstructure. This is because the favorable nano-twinning mechanism was significantly more activated in the textured stainless steel 316L samples during plastic deformation. In addition, kinetic simulations were performed to unveil the relationship between the melt pool geometry and crystallographic texture. The new additive manufacturing strategy of engineering the crystallographic texture can be applied to other metals and alloys with twinning-induced plasticity. This work paves the way to additively manufacture metal parts with high strength and high ductility.NRF (Natl Research Foundation, S’pore)Published versio