Galling wear detection and measurement in sheet metal forming

Galling wear of sheet metal stamping tooling is an expensive issue for sheet metal forming industries. Forming of high strength steels, particularly in the automotive industry, has led to accelerated tool wear rates. These wear rates lead to product quality and die maintenance issues, making galling wear an expensive issue for automotive manufacturers and the sheet metal forming industries in general. Process monitoring allows for the continuous monitoring of tooling condition so that wear development can be detected. The aim of this investigation was to develop an in-depth understanding of the relationship between punch force variation and wear for implementation in future process monitoring regimes. To achieve this aim, the effect of wear and other friction influencing factors on punch force signatures were investigated. This required the development of an accurate method for quantifying galling wear severity so that the relationship between galling wear progression and punch force signature variation could be quantified. Finally, the specific effects of wear and friction conditions on the punch force signatures were examined. An initial investigation using a statistical pattern recognition technique was conducted on stamping force data to determine if the presence of galling wear on press tooling effected punch force variation. Galling wear on tooling, changes in lubrication type, and changes in blank holder pressure were all found to effect variation in punch force signatures shape. A new galling wear severity measurement methodology was developed based on wavelet analysis of 2D surface roughness profiles that accurately provided an indication of the location and severity of galling wear damage. Using the new method for quantifying galling wear severity in the relationship between punch force variation and galling wear progression was investigated, and a strong linear relationship was found. Finally, two prominent vii forms of punch force signature shape variation were linked to friction conditions driven by wear, lubrication, and blank holder pressure. This work describes and quantifies the relationship between galling wear and punch force signature variation. A new methodology for accurate measurement of galling wear severity is presented. Finally, specific forms of punch force signature variation are linked to different friction conditions. These results are critical for future implementation of punch force based galling wear process monitoring and a significant reduction in costs for the metal forming industries

An Environmental and Cost Analysis of Stamping Sheet Metal Parts

Little work has been done on quantifying the environmental impacts and costs of sheet metal stamping. In this work, we present models that can be used to predict the energy requirements, global warming potential, human health impacts, and costs of making drawn parts using zinc (kirksite) die-sets and hydraulic or mechanical presses. The methodology presented can also be used to produce models of stamping using other die materials, such as iron, for which casting data already exists. An unprecedented study on the environmental impacts and costs of zinc die-set production was conducted at a leading Michigan die-maker. This analysis was used in conjunction with electrical energy measurements on forming presses to complete cradle-to-gate impact and cost analyses on producing small batch size hood and tailgate parts. These case studies were used to inform a generalized model that allows engineers to predict the impacts and costs of forming based on as little information as the final part material, surface area, thickness, and batch size (number of units produced). The case studies show that the press electricity is an insignificant contributor to the overall impacts and costs. The generalized models highlight that while costs for small batch production are dominated by the die-set, the environmental impacts are often dominated by the sheet metal. These findings explain the motivation behind the research into die-less forming processes such as incremental sheet forming, and emphasize the need to minimize the sheet metal scrap generation in order to reduce environmental impacts.United States. Department of Energy (Grant DOE/EE-0998

Understanding and developing capabilities for large area and continuous micro contact printing

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 141-143).Micro contact printing is a high spatial resolution-patterning tool that can be used for printing on large and non-planar surfaces because of which it has begun to find important applications in printed organic electronics and fiber optics. However, problems like achieving precise alignment and registration, air bubble trapping and low production rate still remain unresolved. The goal of this thesis is to conceptualize and implement a low cost solution to these problems to be used by a nano-technology based company in Cambridge, Massachusetts. In this dissertation, we first present an extensive literature review of soft lithography techniques, focusing more on micro-contact printing and critical factors for taking this technology from laboratory to commercial production. We then introduce another printing technique called flexography and discuss how this method when combined with micro contact printing can help in overcoming the above stated limitations and at the same time achieve high throughput rate at low cost. We propose a Flexography style micro contact printing mechanism with rotating cylindrical stamps enabling reel to reel processing. Finally, results from the experiments conducted to study the effect of parameters like ink concentration, speed and pressure on the print quality are documented.by Ambika Goel, Sowmya Laxminarayanan and Yun Xia.M.Eng

Design of pulse jet coolant delivery system for minimal quantity lubricant (IP MQL) operation

Minimum quantity lubrication (MQL) machining is one of the promising solutions to the requirement for reducing cutting fluid consumption. The work here describes MQL machining in a range of lubricant consumption of 2.0-2.355ml/s, which is between 10– 100 times lesser than the consumption usually adopted in industries. MQL machining in this range is called pulse jet coolant delivery system. A specially designed system, the IP MQL, was used for concentrating small amounts of lubricant onto the cutting interface. The performance of concentrated spraying of lubricant in pulse jet coolant delivery system design was simulated and compared with that of current ‘Pulse Jet MQL’ systems. The concentrated spraying of lubricant with a specially designed system was found to be effective in increasing tool life in the pulse jet coolant delivery system range

EXTENDING ORIGAMI TECHNIQUE TO FOLD FORMING OF SHEET METAL PRODUCTS

This dissertation presents a scientific based approach for the analysis of folded sheet metal products. Such analysis initializes the examination in terms of topological exploration using set of graph modeling and traversal algorithms. The geometrical validity and optimization are followed by utilizing boundary representation and overlapping detection during a geometrical analysis stage, in this phase the optimization metrics are established to evaluate the unfolded sheet metal design in terms of its manufacturability and cost parameters, such as nesting efficiency, total welding cost, bend lines orientation, and maximum part extent, which aides in handling purposes. The proposed approach evaluates the design in terms of the stressed-based behavior to indicate initial stress performance by utilizing a structural matrix analysis while developing modification factors for the stiffness matrix to cope with the stress-based differences of the diverse flat pattern designs. The outcome from the stressed-based ranking study is mainly the axial stresses as exerted on each element of folded geometry; this knowledge leads to initial optimizing the flat pattern in terms of its stress-based behavior. Furthermore, the sheet folding can also find application in composites manufacturing. Thus, this dissertation optimizes fiber orientation based on the elasticity theory principles, and the best fiber alignment for a flat pattern is determined under certain stresses along with the peel shear on adhesively bonded edges. This study also explores the implementation of the fold forming process within the automotive production lines. This is done using a tool that adopts Quality Function Deployment (QFD) principle and Analytical Hierarchy Process (AHP) methodology to structure the reasoning logic for design decisions. Moreover, the proposed tool accumulates all the knowledge for specific production line and parts design inside an interactive knowledge base. Thus, the system is knowledge-based oriented and exhibits the ability to address design problems as changes occur to the product or the manufacturing process options. Additionally, this technique offers two knowledge bases; the first holds the production requirements and their correlations to essential process attributes, while the second contains available manufacturing processes options and their characteristics to satisfy the needs to fabricate Body in White (BiW) panels. Lastly, the dissertation showcases the developed tools and mathematics using several case studies to verify the developed system\u27s functionality and merits. The results demonstrate the feasibility of the developed methodology in designing sheet metal products via folding

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

ANALYSIS OF PART CONSOLIDATION TECHNIQUES FOR AUTOMOTIVE BODY IN WHITE PANELS BASED ON ADVANCED SHEET METAL FORMING TECHNOLOGIES

The automotive industry is looking to move from mass production to mass customization in order to manufacture and sell a variety of products in different markets on a global scale. This requires a robust and cost effective manufacturing system which would help design new products in the shortest possible lead time. This thesis tries to investigate the current sheet metal forming process for body in white, identify the limitations and propose an alternative which would help the industry cut down product lead time and costs. Decision making tools are used to identify the technical requirements of a BIW manufacturing system and optimize the same. Part consolidation techniques are studied in detail and the various means to achieve them are investigated. Industrial origami¨ is proposed as an alternative to automotive stamping and a means to achieve part consolidation. Origami joints and their design features were modeled using cad tools and their load bearing and strength characteristics are compared to that of stamped joints using finite element analysis simulations. A bill of materials of a small sedan is constructed to identify the opportunities for part consolidation and process substitution of stamping using origami

New manufacturing techniques for antennas

This paper is a discussion of new manufacturing techniques for antennas. Many existing manufacturing methods, including conductive ink printing, plastic plating, hot foil printing, etching, sintering and die cutting, are investigated to determine their usefulness in the manufacture of antennas. The advantages and disadvantages of each are discussed, and the most promising method—plating on plastic—is further analysed. The method of adapting the plating technique so that it can be used for antennas is discussed. Two prototype antennas (a PIFA and omni antenna) were manufactured to test the plating method’s effectiveness as a manufacturing technique for antennas. Results showed a frequency shifted VSWR pattern for the PIFA antenna of 10% on each notch. The gain plot for the omni antenna showed a higher gain for the plated antenna at a frequency shifted by approximately 0.4 GHz. A cost analysis was also performed to complete the investigation of the new manufacturing method. A saving of up to 4 000% can be realised on the substrate material, and the metal costs can be lowered by 700% for each PIFA antenna