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New Solutions for One Shot Hand Held and Robot Drilling of CFRP/Titan and -/Aluminium Stack Drilling in H8 Quality for Aerospace Applications

Up to now, the reliability achieved by COTS components was largely sufficient for avionics, in terms of failure rate as well as time to failure. With the implementation of new and more integrated technologies (90 nm node, 65 nm and below), the question has arisen of the impact of the new technologies on reliability. It has been stated that the lifetime of these new technologies might decrease. The drift is expected to be technology dependent: integration, technology node, materials, elementary structure choices and process pay a key role. Figures have been published, which gives smaller lifetime than the 30 years generally required for avionics. This would of course impact not only the reliability, but also the maintenance of COTS-based avionics. Hence a new policy should be defined for the whole COTS supply chain. Faced with these impending risks, different methodologies have been developed.

High Speed Machining of CFRP Parts

High Speed Machining of CFRP Parts Investigation of the influence of new geometries, cutting datas and coolant capabilities on the surface finish of CFRP parts. State of the art: Different CFRP grades and machining conditions make geometry adjustments to the tool necessary. Mechanical failures through machining operations can be avoided in most of the cases. New unidirectional CFRP grades and dry machining processes again lead to machining problems. This study investigates new geometries to avoid heat damage with dry maching and air coolant in case of unidirectional CFRP. With help of a thermo camera and the surface investigation with a scanning electron microscope, heat damage can be analysed and therefore new geometries can be developed and tested. Target is to develop a new multi purpose CFRP geometry to meet the requirements of the future. The reduction of different geometries used leads to major cost savings. Presenter Ingo von Puttkamer, Guhring oHG

Study of Exit Burr Formation and Exit Burr Reduction in Automated Drilling of Titanium Stacked With Carbon Fiber Composite

A series of flight tests were conducted to design and evaluate a Combined Vision System (CVS) that integrates a forward looking infrared video image with synthetic vision on a primary flight display. System features included colorizing the video image to mesh with the synthetic terrain background, decluttering the approach symbology to facilitate the detection of the approach lights and runway markings, creating a semi-transparent IR sky to ensure continuous situational awareness of the surrounding terrain, and annunciating the decision height to facilitate the transition to the actual runway environment. Over 100 approaches were flown during three flight test sessions. For the first flight test session pilots reviewed early CVS proofs of concept on Honeywell's Citation Sovereign.

Automating AFP Tuning Using a Laser Sensor

A significant step is achieved on the flight control actuation system toward the more electrical aircraft through the Airbus A380, A400M and the A350 development phase ongoing. The A380/A400M/A350 features a mixed flight control actuation power source distribution, associating electrically powered actuators with conventional FlyByWire hydraulic servocontrols. In the scope of the preparation of the future Airbus Aircraft, this paper presents the perspectives of the use of the EMA technologies for the flight control systems in the more electrical aircraft highlighting the main technical challenges need to treat: jamming susceptibility, ?on board? maintenance reduction, Operational reliability increase, power electronics and power management optimization, and regarding the environmental constraints, the predicted performances; the benefits associated to the optimized utilization of on-board power sources.
Journal Article

Optimization of WEDM Cutting Parameters on Surface Roughness of 2379 Steel Using Taguchi Method

Abstract Surface roughness is one of the important aspects in producing quality die. Wire Electrical Discharge Machine (WEDM) is commonly used in tool and die fabrication, since the die material is usually difficult to cut using traditional metal removal processes. Selection of optimal WEDM cutting parameters is crucial to obtain quality die finish. In this study, 2379 steel which equivalent to SKD 11 is selected as the die material. Four main WEDM cutting parameters, namely, pulse duration (A), pulse interval (B), servo voltage (C), ignition pulse current (D), were experimentally evaluated for both main cut and multiple trim cuts using Taguchi Method. Taguchi’s L9 orthogonal array is employed for experimental design and analysis of variance (ANOVA) was used in recognizing levels of significance of WEDM cutting parameters.
Journal Article

Optimization Approach of Turning Process of Multiwalled Carbon Nanotubes-Aluminium Oxide/Epoxy Hybrid Nanocomposites

Abstract The high quality of the machined parts in a short time is a research challenge for enhancing these parts’ operating performance. Optimizing the machining operations and adequately selecting the cutting parameters can solve this challenge. Thus, this work proposes an optimization approach of the machining process parameters of epoxy hybrid nanocomposites reinforced by multiwall carbon nanotubes (MWCNTs) and aluminum oxide (Al2O3). Cutting speed (V), feed rate (F), insert nose radius, and depth of cut (D) were the machining parameters. The roundness error and surface roughness (Ra) were selected as process response control parameters. The optimization techniques such as response surface method (RSM) and grey relation analysis (GRA) with the variance of analysis (ANOVA) were involved. Forty experimental runs were performed. The RSM optimization and ANOVA results showed that the insert nose radius and F are the most significant factors that affect the Ra.
Journal Article

Machining Quality Analysis of Powertrain Components Using Plane Strain Finite Element Cutting Models

Abstract Finite Element Analysis (FEA) of metal cutting is largely the domain of research organizations. Despite significant advances towards accurately modelling metal machining processes, industrial adoption of these advances has been limited. Academic studies, which mainly focused on orthogonal cutting, fail to address this discrepancy. This paper bridges the gap between simplistic orthogonal cutting models and the complex components typical in the manufacturing sector. This paper outlines how to utilize results from orthogonal cutting simulations to predict industrially relevant performance measures efficiently. In this approach, using 2D FEA cutting models a range of feed, speed and rake angles are simulated. Cutting force coefficients are then fit to the predicted cutting forces. Using these coefficients, forces for 3D cutting geometries are calculated.
Journal Article

Improving Hole Expansion Ratio by Parameter Adjustment in Abrasive Water Jet Operations for DP800

Abstract The use of Abrasive Water Jet (AWJ) cutting technology can improve the edge stretchability in sheet metal forming. The advances in technology have allowed significant increases in working speeds and pressures, reducing the AWJ operation cost. The main objective of this work was to determine the effect of selected AWJ cutting parameters on the Hole Expansion Ratio (HER) for a DP800 (Dual-Phase) Advanced High-Strength Steel (AHSS) with s0 = 1.2 mm by using a fractional factorial design of experiments for the Hole Expansion Tests (HET). Additionally, the surface roughness and residual stresses were measured on the holes looking for a possible relation between them and the measured HER. A deep drawing quality steel DC06 with s0 = 1.0 mm was used for reference. The fracture occurrence was captured by high-speed cameras and by Acoustic Emissions (AE) in order to compare both methods.


This specification covers one type of high-contrast, medium-grain radiographic film in the form of cut sheets or rolls.
Journal Article

Mechanical Performance of Circular AA6061-T6 Extrusions Under Axial Cutting Deformation

Dynamic and quasi-static axial cutting of circular AA6061-T6 extrusions with variable instantaneous wall thickness in the axial direction was completed to investigate the capability of controlling the load/displacement responses of the extrusions. Circular specimens considered for this research had an original nominal wall thickness of 3.175 mm, an external diameter of 50.8 mm, and a tube length of 300 mm. Variations of the wall thickness were completed by material removal of the extrusions using a CNC machine. Specially designed cutters having a block height of 20 mm, a blade tip width of 1.0 mm and a blade shoulder width of 3.0 mm were employed to generate the axial cutting deformation mode. Either one or two cutters were selected to initiate a single or dual cutting deformation. A curved deflector with a profile radius of 50.8 mm was used to flare the cut petalled sidewalk and facilitate the cutting system.
Journal Article

Effect of Machining Feed on Surface Roughness in Cutting 6061 Aluminum

The general manufacturing objective during the fabrication of automotive components, particularly through machining, can be stated as the striving to achieve predefined product quality characteristics within equipment, cost and time constraints. The current state of the economy and the consequent market pressure has forced vehicle manufacturers to simultaneously reduce operating expenses along with further improving product quality. This paper examines the achievability of surface roughness specifications within efforts to reduce automotive component manufacture cycle time, particularly by changing cutting feeds. First, the background and attractiveness of aluminum as a lightweight automotive material is discussed. Following this, the methodologies employed for the prediction of surface roughness in machining are presented. The factors affecting surface roughness as well as practical techniques for its improvement through optimizing machining parameters are discussed next.
Journal Article

Development of Precision Rolling Machine

This paper proposes a rolling machine that forms fine corrugated section patterns for thin sheets. A prototype of the machine was made and the performance of the machine was tested. As compared with press forming, rolling has the advantages of the high forming limit, the low forming reaction force, the easy control of the thin sheet's curve and high productivity. We confirmed these four advantages by using finite element analyses and the prototype rolling machine. Stainless steel sheets and titanium sheets, which were one of the materials with a low forming limit, were used. Firstly, the rolling showed a 1.3-times higher forming limit than the press forming in the case that a fine corrugated section pattern was formed in a stainless steel sheet of 22-mm square sizes. Secondly, the forming reaction force of the rolling was about one-twentieth of the press forming without coining, and the experimental results agreed with the finite element simulation.
Journal Article

An Experimental Study Investigating the Influence of the Number of Blades in a Cutter Used in Axial Cutting of AA6061-T6 and T4 Round Tubes

Quasi-static axial cutting of AA6061-T6 and T4 round extrusions were completed using a specially designed cutter with multiple blades. The round specimens had a length of 200 mm, a nominal outer diameter of 50.8 mm, and a wall thickness of 3.175 mm or 1.587 mm. Four different cutters, constructed from heat-treated 4140 steel, having 3, 4, 5 and 6 blades on each cutter with a nominal tip width of 1.0 mm were used to penetrate through the round extrusions. A clean cutting mode was observed for the AA6061-T6 and T4 extrusions with wall thickness of 3.175 mm with an almost constant steady state cutting force. A braided cutting mode was observed for extrusions with both tempers with wall thickness of 1.587 mm, which resulted in a slightly oscillating steady state cutting force. For all extrusions with a wall thickness of 3.175 mm, the steady state cutting force increased with an increase in the number of cutter blades.
Journal Article

Laser Profilometry For Non-Contact Automated Countersink Diameter Measurement

Automated countersink measurement methods which require contact with the workpiece are susceptible to a loss of accuracy due to cutting debris and lube build-up. This paper demonstrates a non-contact method for countersink diameter measurement on CFRP which eliminates the need for periodic cleaning. Holes are scanned in process using a laser profilometer. Coordinates for points along the countersink edge are processed with a unique filtering algorithm providing a highly repeatable estimate for major and minor diameter.
Journal Article

New Vibration System for Advanced Drilling Composite-Metallic Stacks

To reduce the weight of aero structures, composite materials are combined with metallic parts. These multilayer materials are one-shot drilled during the assembly process. During drilling, interactions appear between the different layers creating new quality issues. To improve machining efficiency, the portable semi-automated drilling units commonly used for such operations need to be upgraded. For this purpose, vibration systems have been recently introduced into drilling units. This article first considers the effect of the reciprocating axial movement on the quality of the machined surface, then focuses on the effect of the oscillation parameters (frequency, magnitude) on the cutting process (cutting forces, thermal load, etc.). Experimental and numerical results are used to find the method that produces the optimal vibration setting. This method is then applied to the case of drilling composite-metallic stack.
Journal Article

Wear Dependent Tool Reliability Analysis during Cutting Titanium Metal Matrix Composites (Ti-MMCs)

Metal matrix composites (MMCs) exhibit superior characteristics such as low weight, high stiffness, and high mechanical and physical properties. Inheriting such an outstanding combination of specifications, they are nowadays considered as the promising materials in the aerospace and biomedical industries. However, the presence of high abrasive reinforcing particles in MMCs leads to severe manufacturing issues. Due to the tool-particle interactions which occur during the machining of MMCs, high tool wear and poor surface finish are induced and those elements are considered as the main drawbacks of cutting MMCs. In this study, dry turning experiments were conducted for two different inserts and coated carbide on a bar of titanium metal matrix composite (Ti-MMC). Semi-finishing machining is operated with cutting parameters based on the tool supplier's recommendations which were not fully optimized. The maximum flank wear length (VBBmax) was selected as the tool wear criteria.
Journal Article

Experimental Study of Interaction between Brake-Disc Surface Texture and Friction Material on Friction and Wear through Small-Scale Tests on Tribotester

There are various processes for finishing the friction surfaces of a brake disc, which affect the braking effectiveness of a vehicle in the early stages of use in some cases. To examine the interaction between the disc surface texture, rotational direction, and friction material, a series of experiments on a tribotester using small-scale specimens was conducted. In a previous paper (2013-01-2056), the results from the first series of experiments, which involved of thirty disc surface textures and a less aggressive non-asbestos organic (NAO) friction material in on-brake-drag conditions combining constant speed and normal-load, was reported. Disc surfaces were finished by the following finishing processes in two rotational directions: turning under four cutting conditions, roller burnishing after turning, turning with a wiper insert, and grinding with two stones. Contact-pressure dependency of friction and wear was confirmed.
Technical Paper

Analytical Study on Influence of Shape of Bucket Cutting Edge of a Wheel Loader on Load Transfer

Wheel loader is a heavy construction equipment, which is commonly used in construction, mining, transferring material etc. According to off highway research about Construction Equipment analysis in India, Wheel loader market is continuously growing because of road construction and mining [1]. One of the parameters which influences the productivity of the machine, is shape of the cutting edge of loader bucket. Poor design of bucket cutting edge results in poor digging, which ultimately affects machine performance and durability. In a wheel loader working cycle, the trajectory of the bucket structure is complicated and variable, which lead to complex working conditions. Cutting edge is the part of Wheel loader bucket, on which the OEMs put a lot of efforts in improving the penetration into the pile and performance. The maximum applied force on bucket cutting edges depend on working load conditions.