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Technical Paper

49 Development of Pb-free Free-Cutting Steel Enabling Omission of Normalizing for Crankshafts

Crankshafts of motorcycles require high strength, high reliability and low manufacturing cost. Recently, a reduction of Pb content in the free-cutting steel, which is harmful substance, is required. In order to satisfy such requirements, we started the development of Pb-free free-cutting steel which simultaneously enabled the omission of the normalizing process. For the omission of normalizing process, we adjusted the content of Carbon, Manganese and Nitrogen of the steel. This developed steel can obtain adequate hardness and fine microstructure by air-cooling after forging. Pb-free free-cutting steel was developed based on Calcium-sulfur free-cutting steel. Pb free-cutting steel is excellent in cutting chips frangibility in lathe process. We thought that it was necessary that cutting chips frangibility of developed steel was equal to Pb free-cutting steel. It was found that cutting chips frangibility depend on a non-metallic inclusion's composition, shape and dispersion.
Technical Paper

A Case Study of a Full Inverse Poroelastic Characterization of an Open-Cell Porous Material Using an Impedance Tube: The Need to Properly Prepare the Material and to Control the Measurement

This paper presents a case study on the full inverse characterization of the material properties of an open-cell poroelastic foam using impedance tube measurements. It aims to show the importance of controlling the lateral boundary condition in the impedance tube, and selecting an appropriate acoustic model to obtain the most accurate material properties. The case study uses a four-inch thick melamine foam and a 100-mm diameter tube. The foam is mechanically cut to fit within the circular tube. However, the cutting process is not perfect and a tiny lateral air gap exists between the material and the tube (i.e. the foam diameter is 99.5 mm for a 100-mm diameter tube). The typical characterization procedure is to mix direct and indirect measurements to retrieve the material properties of the foam. First, open porosity, bulk density, and static airflow resistivity are directly measured.
Technical Paper

A Comparative Study on Machinability Characteristics in Dry Machining of Inconel X-750 Alloy Using Coated Carbide Inserts

Nickel based superalloys have a wide range of applications due to high mechanical strength at high temperatures, fracture toughness and resistance to corrosion. However, because of their outstanding properties, it is considered as the difficult to machine materials. Inconel alloy X-750 is used extensively in rocket-engine thrust chambers. Airframe applications include thrust reversers and hot-air ducting systems along with large pressure vessels are formed from Inconel alloy X-750. Moreover, the comparative analysis of machinability aspect using coated carbide inserts is reported few. The current study explains the machinability investigation on Inconel alloy X-750 superalloys using coated carbides. To collect the experimental data, the L16 experimental design plan is used to experiment with a machining length of 40 mm.
Technical Paper

A Comparison of the Mechanical Performance of AA6061-T6 Extrusions Subjected to Axial Crushing and Axial Cutting

Conventional axially loaded energy absorbers dissipate kinetic energy through progressive folding. The significant fluctuations in load and high risk of transition to global bending are drawbacks that engineers have attempted to mitigate through several methods. A novel energy dissipation mechanism, referred to as axial cutting, utilizes thin-walled extrusions and a strengthened cutting tool to absorb energy in an axial impact. Compared to progressive folding, this can be achieved with minimal fluctuations in load during the deformation process. Based upon estimates from finite element models, a series of test cases were postulated where, for 8 and 10-bladed cutting scenarios, greater total energy absorption could be achieved through axial cutting than with progressive folding of geometrically similar extrusions. The specimens were AA6061 extrusions having T6 temper conditions that possessed 63.5 mm outer diameters and 1.5 mm wall thicknesses.
Technical Paper

A Comprehensive Study of Hole Punching Force for AHSS

The elevated strength of advanced high strength steels (AHSS) leads to enormous challenges for the sheet metal processing, one of which is hole punching operation. The total tonnage must be estimated at each trimming stage to ensure successful cutting and protect the press machine. This paper presents the effects of hole punch configurations on the punching force with the consideration of punch shape, cutting clearance and material grade. The hole punching experiments were performed with DP590, DP980, DP1180 and one mild steel as a reference. The punching force coefficient is defined and presents a negative correlation with the material strength based on the experimental data. Surface quality was examined to analyze the damage accumulation during the punching process. The cutting mechanisms with various punch shapes were revealed through an extensive finite element simulation study.
Journal Article

A Coupled Eulerian Lagrangian Finite Element Model of Drilling Titanium and Aluminium Alloys

Despite the increasing use of carbon fibre reinforced plastic (CFRP) composites, titanium and aluminium alloys still constitute a significant proportion of modern civil aircraft structures, which are primarily assembled via mechanical joining techniques. Drilling of fastening holes is therefore a critical operation, which has to meet stringent geometric tolerance and integrity criteria. The paper details the development of a three-dimensional (3D) finite element (FE) model for drilling aerospace grade aluminium (AA7010-T7451 and AA2024-T351) and titanium (Ti-6Al-4V) alloys. The FE simulation employed a Coupled Eulerian Lagrangian (CEL) technique. The cutting tool was modelled according to a Lagrangian formulation in which the mesh follows the material displacement while the workpiece was represented by a non-translating and material deformation independent Eulerian mesh.
Technical Paper

A Flexible Production Environment

New technologies, evolving customer requirements, different process procedures, part changes, inequities between CAD model and actual fixtures and parts, and other problems all require a flexible process environment. However, increased process complexities place a burden on production operators. CIMCORP has developed a flexible environment for drilling, routing and waterjet cutting composites. The system accepts off-line CAD/CAM generated part programs, allows on-line creation and editing of programs, integrates customer expertise to help optimize production, yet maintains a simple production level environment. The environment utilizes pop-up menus and pull down interaction windows to reduce operator input to known values. An on-line RS-274 editor, communication with intelligent peripheral devices, and system administration screens for reconfiguration of process parameters are also included.
Technical Paper

A Methodology for Determining Process and System-Level Manufacturing Performance Metrics

Given the low business safety margins of today's highly competitive marketplace and companies' inevitable efforts towards cutting cost and continuous improvement, the automotive industry, as well as other manufacturing arenas, are in a deep need for developing quantifiable definitions of their relevant performance improvement criteria. Manufacturing operations often represents the core of a company's business strategy. Hence, this paper describes an analytical and a simulation-based integrated methodology for determining Manufacturing Performance Metrics (MPMs) at both process and system levels. The proposed methodology focuses on determining MPMs associated with four key Industrial Engineering criteria: Productivity, Quality, Reliability, and Effectiveness (PQRE). Other criteria such as Cost and Safety, which are commonly used in conjunction with the PQRE criteria for systems design and improvement, are not the focus of this paper.
Technical Paper

A Model of Vibratory Soil Cutting

A lumped parameter model consisting of a spring and coulomb friction is developed to simulate soil cutting by a plow blade vibrating horizontally. The spring represents blade and soil elasticity; the coulomb friction represents soil strength. Predicted instantaneous and average forces agree favorably with those obtained experimentally for a sinusoidally vibrating blade in a compacted silty sand. Results indicate that, for a given cutting speed, average force can be reduced by increasing frequency, displacement amplitude, and/or system stiffness. For practical design values of these parameters, the force can be reduced to 25% of the nonvibrating cutting force. Further reductions can be achieved only by large increases in the parameters.
Technical Paper

A New Line of 600 Series Tandem Disks

The new Series 600 John Deere Disks are designed for optimum disking performance in primary and secondary tillage conditions. The tandem design retains the performance characteristics of double offset configurations due to an exclusive rolling disk middlebreaker. Welded main and wing frames feature large square and rectangular tubes which are manufactured on common weld fixtures, providing a strong “family” appearance as well as reduced factory setups and inventories. These disks provide farmer-customers with many options and features necessary to operate in varying soil types and conditions while achieving level disking performance and uniform cutting action.
Technical Paper

A New Method of TESTING AND GRADING Fine Abrasives

THE difficulty of selecting the proper abrasives or “stones” for Superfinishing machines made by his company, because of the “apparent inability of stone manufacturers to grade the hardness of the bond properly and uniformly,” led to the development described, Mr. Hemingway explains. Reciting the difficulties encountered in Superfinishing operations due to lack of correct bond grading he declares that, when a stone of too great hardness is applied to a ground surface, its too-rigidly-held grits are not removed to dress and sharpen its face and the cutting action slows down much sooner than desired. When the stone used has too little bond strength its action on the hill peaks results in an extremely rapid removal of metal as the stone breaks down very fast. After describing various preliminary tests, he reveals that a Rockwell hardness tester with a ⅛-in. steel ball and a 60-kg load finally was selected for grading Superfinishing stones.
Technical Paper

A Nonlinear Automatic Feedback Blade Controller for Improved Bulldozer Performance

Underwater bulldozers have been built for development of the ocean floor. Yet it is impractical for a diver to operate an underwater bulldozer from within the vehicle. Remote control of a bulldozer is extremely difficult due to complicated relationships between vehicle inclination, blade cylinder deflection, and the terrain profile in front of the bulldozer. In this paper a nonlinear automatic feedback blade control system is designed to replace direct operator control of the blade. To accomplish this design, mathematical models were developed for the vehicle dynamics and the hydraulic system dynamics of a typical bulldozer. Since both subsystem models are complicated nonlinear ones, the blade control system was designed using only a simplified hydraulic system model. The performance of the complete nonlinear system with the blade feedback control system added was then investigated using a hybrid computer simulation compared to available experimental data using a skilled operator.
Technical Paper

A Parametric Simulation Model for Analyzing the Performance of a Steel-Tracked Feller Buncher

A parametric simulation model of a steel-tracked feller buncher was developed1. This model can be used to predict the lift capacity, side tipping angles, grade-ability, and joint forces during a cutting cycle. The feller buncher is defined parametrically, allowing the user to quickly analyze different machine configurations simply by changing the value of a variable. Several simulations were performed to illustrate the application of the model.
Technical Paper

A Proposed Entry System for the Conveyance of Uncured SMC into a Pyrolysis System

This paper describes an entry system that could be used to convey uncured sheet molding composite (SMC) into a pyrolysis system. This entry system consists of: a compression chamber, a cutting chamber, and a final temperature control chamber. This research was accomplished through a joint effort of the Eagle Picher Plastic Division and the Thayer School of Engineering, Dartmouth College on behalf of the SMCAA. Motivation for this research is the total recycling goal of all thermoset composites by the SMCAA.
Technical Paper

A Rapid Assessment Technique for the Screening of Sweetpotato for Use in Bioregenerative Life Support Applications

Single leaf sweetpotato cuttings were used for rapid screening of a sample population for adaptation to hydroponics. Leaves cut at the union with the stem were planted in channels covered with white plastic. Holes were punctured through the plastic for the leaf petiole to stand in the channels. They grew in an environmental chamber at 28/22° C, 70% relative humidity and 14 hours light regime at 600 μmol m −2 s−1/10 hours dark. Five leaves per line were evaluated after 14 days. This technique differentiated the performance of genotypes and showed that there is much variability for the characters measured.
Technical Paper

A Study on Autonomous Hole Machining Process Analysis by Reverse Engineering of NC Programs

The machining know-how or knowledge exists in the NC programs if they are generated through experienced workers. To realize autonomous CNC machining, accumulation and representation of such know-how in a reusable way is needed. In this paper, an autonomous machining process analyzer for hole machining is studied. With the method, the machining process can be analyzed and the know-how can be extracted from existing successful NC programs. Specifically, machining feature, operation sequence, and cutting parameters including used tools, feedrate and spindle/cutting speed can be extracted. Based on the proposed method, a prototype system has been developed to verify the feasibility of the know-how extraction.
Technical Paper

A Test Comparison of Model and Full-Size Bulldozer Blades

Five geometrically similar bulldozer blades, ranging in width 6.45-77.2 in., were tested in four different soil types. Tests were run at low speed and a constant cutting depth equal to 20% of blade height. Horizontal and vertical soil forces, soil force moments, and travel distances were measured. An analysis of the test data is presented and a method of predicting the draft force of larger blades from tests on smaller scale models is proposed. Test equipment, instrumentation, and test technique are described.