Controlled Plasticity Burnishing to Improve the Performance of Friction Stir Processed Ni-Al Bronze

2007 ◽  
Vol 539-543 ◽  
pp. 3807-3813 ◽  
Author(s):  
Paul S. Prevey ◽  
Douglas J. Hornbach ◽  
N. Jayaraman
Keyword(s):  
Salt Solution ◽  
Local Heating ◽  
Fatigue Performance ◽  
Cnc Machine Tools ◽  
Neutral Salt ◽  
Cnc Machine ◽  
Treatment Technology ◽  
Friction Stir ◽  
Tool Positioning ◽  
Post Process

Friction stir welding (FSW) allows the joining of aluminum alloys in ways previously unattainable offering new manufacturing technology. Friction stir processing (FSP) of cast alloys such as Ni-Al bronze eliminates casting voids and improves the properties to that of wrought material. However, the local heating produced by both FSW and FSP can leave a fusion zone with reduced mechanical properties and a heat-affected zone with tensile residual stresses that can be deleterious to fatigue performance. Controlled plasticity burnishing (CPB) is an established surface treatment technology that has been investigated and described extensively for the improvement of damage tolerance, corrosion fatigue, and stress corrosion cracking performance in a variety of alloys. Mechanical CPB processing in conventional CNC machine tools or with robotic tool positioning is readily adapted to industrial FSW and FSP fabrication of components, either simultaneously or as a post process. CPB was applied to FSP Ni-Al Bronze to produce a depth of compression of 2.5 mm and a maximum subsurface magnitude of –150 ksi. The effect of FSP on the fatigue performance in a saltwater marine environment and in the presence of foreign object damage (FOD) was documented with and without CPB processing. FSP was found to increase the fatigue strength of the Ni-Al Bronze by 70% without affecting the corrosion behavior of neutral salt solution. FSW actually produced a more noble material in the acidic salt solution. CPB after FSP mitigated damage 1 mm deep.

Mitigation of Fretting Fatigue Damage in Blade and Disk Pressure Faces With Low Plasticity Burnishing

2007 ◽  
Author(s):  
Paul S. Preve´y ◽  
N. Jayaraman ◽  
Ravi A. Ravindranath ◽  
Michael Shepard
Keyword(s):  
Gas Turbine ◽  
Design Method ◽  
Surface Damage ◽  
Gas Turbine Engine ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Residual Stress Field ◽  
Treatment Technology ◽  
Turbine Engine ◽  
Low Plasticity Burnishing

Low Plasticity Burnishing (LPB) is now established as a surface enhancement technology capable of introducing through-thickness compressive residual stresses in the edges of gas turbine engine blades and vanes to mitigate foreign object damage (FOD). The “Fatigue Design Diagram” (FDD) method has been described and demonstrated to determine the depth and magnitude of compression required to achieve the optimum high cycle fatigue (HCF) strength, and to mitigate a given depth of damage characterized by the fatigue stress concentration factor, kf. LPB surface treatment technology and the FDD method have been combined to successfully mitigate a wide variety of surface damage ranging from FOD to corrosion pits in titanium and steel gas turbine engine compressor and fan components. LPB mitigation of fretting induced damage in Ti-6AL-4V in laboratory samples has now been extended to fan and compressor components. LPB tooling technology recently developed to allow the processing of the pressure faces of fan and compressor blade dovetails and mating disk slots is described. Fretting induced micro-cracks that form at the pressure face edge of bedding on both the blade dovetail and the dovetail disk slots in Ti-6-4 compressor components can now be arrested by the introduction of deep stable compression in conventional CNC machine tools during manufacture or overhaul. The compressive residual stress field design method employing the FDD approach developed at Lambda Technologies is described in application to mitigate fretting damage. The depth and magnitude of compression and the fatigue and damage tolerance achieved are presented. It was found that microcracks as deep as 0.030 in., (0.75 mm) large enough to be readily detected by current NDI technology, can be fully arrested by LPB. The depth of compression achieved could allow NDI screening followed by LPB processing of critical components to reliably restore fatigue performance and extend component life.

Study on Post-Processing of Five-Axis Cnc Machining

2011 ◽  
Vol 141 ◽  
pp. 524-528
Author(s):  
Jing Zhang Zhi ◽  
Cheng Zu Ren ◽  
Jing Chuan Dong
Keyword(s):  
Coordinate System ◽  
Machine Tools ◽  
Cnc Machining ◽  
Cnc Machine Tools ◽  
Post Processing ◽  
Cnc Machine ◽  
Post Process ◽  
Non Linear ◽  
Position And Orientation ◽  
Five Axis

According to the feature of five-axis CNC machine tools’structure, do researches on post-process technique. By means of analysis of the kinetic model of five-axis CNC machine tools, Position and orientation of the tool in the workpiece coordinate system transforms to that of the machine coordinate system. Besides, Because of the rotation，Five-axises maching will produce the non-linear error．This article provides an easy algorithm to find the maximum non-linear error. Finally, an impeller, for example, simulates in the computer and machine by a 5-axis machine tool.

Mitigation of Fretting Fatigue Damage in Blade and Disk Pressure Faces With Low Plasticity Burnishing

2010 ◽  
Vol 132 (8) ◽  
Author(s):  
Paul S. Prevéy ◽  
N. Jayaraman ◽  
Ravi A. Ravindranath ◽  
Michael Shepard
Keyword(s):  
Gas Turbine ◽  
Design Method ◽  
Gas Turbine Engine ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Residual Stress Field ◽  
Treatment Technology ◽  
Turbine Engine ◽  
Low Plasticity Burnishing

Low plasticity burnishing (LPB) is now established as a surface enhancement technology capable of introducing through-thickness compressive residual stresses in the edges of gas turbine engine blades and vanes to mitigate foreign object damage (FOD). The “fatigue design diagram” (FDD) method has been described and demonstrated to determine the depth and magnitude of compression required to achieve the optimum high cycle fatigue strength, and to mitigate a given depth of damage characterized by the fatigue stress concentration factor, kf. LPB surface treatment technology and the FDD method have been combined to successfully mitigate a wide variety of surface damage ranging from FOD to corrosion pits in titanium and steel gas turbine engine compressor and fan components. LPB mitigation of fretting-induced damage in Ti–6Al–4V in laboratory samples has now been extended to fan and compressor components. LPB tooling technology recently developed to allow the processing of the pressure faces of fan and compressor blade dovetails and mating disk slots is described. Fretting-induced microcracks that form at the pressure face edge of bedding on both the blade dovetail and the dovetail disk slots in Ti-6-4 compressor components can now be arrested by the introduction of deep stable compression in conventional computer numerical control (CNC) machine tools during manufacture or overhaul. The compressive residual stress field design method employing the FDD approach developed at Lambda Technologies is described in application to mitigate fretting damage. The depth and magnitude of compression and the fatigue and damage tolerance achieved are presented. It was found that microcracks as deep as 0.030in.(0.75mm) large enough to be readily detected by current nondestructive inspection (NDI) technology can be fully arrested by LPB. The depth of compression achieved could allow NDI screening followed by LPB processing of critical components to reliably restore fatigue performance and extend component life.

Influence of CNC Machine Tool Technical Condition on the Geometrical Accuracy of Freeform Surfaces

2013 ◽  
Vol 199 ◽  
pp. 315-320 ◽  
Author(s):  
Łukasz Czerech ◽  
Roman Kaczyński
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Technical Condition ◽  
Cnc Machine Tools ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Freeform Surfaces ◽  
Tool Positioning ◽  
Geometric Deviations ◽  
Roundness Deviation

The paper presents results of diagnostic tests for a CNC machine tool used for manufacturing elements with restricted freeform surfaces. Some selected errors possible to identify and estimate in numerically controlled machine tools using a QC20-W Ballbar were described and analyzed. The following parameters were subjected to thorough analysis: roundness deviation, perpendicularity and straightness deviation, cyclic error, backlash and reversal spike. The tests made it possible to carry out a correction of selected components of total tool positioning error and their influence on the process of geometric deviations of curvilinear surfaces produced with CNC machine tools.

scholarly journals Dynamic Interaction between Machine, Tool, and Substrate in Bobbin Friction Stir Welding

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Mohammad K. Sued ◽  
Dirk J. Pons
Keyword(s):  
Friction Stir Welding ◽  
Situational Factors ◽  
Numerical Control ◽  
Weld Quality ◽  
Negative Consequences ◽  
Cnc Machine ◽  
Friction Stir ◽  
Tool Holder ◽  
Tool Positioning ◽  
Machine Type

The bobbin friction stir welding (BFSW) process has benefits for welding aluminium alloy 6082-T6 in the boat-building industry. However this alloy is difficult to weld in the thin state. There are a large number of process variables and covert situational factors that affect weld quality. This paper investigates how tool holder and machine-type affect BFSW weld quality of 4 mm Al6082-T6. The variables were tool features (three types), machine-controller type (two types), and tool holder (fixed versus floating). Fourier analysis was performed on motor spindle current to determine the frequency response of the machine. An interaction was found between the computer numerical control (CNC), the degrees of freedom of the tool holder, and the substrate (workpiece). The conventional idea that the welding tool has a semisteady interaction with the substrate is not supported. Instead the interaction is highly dynamic, and this materially affects the weld quality. Specific vibrational interactions are associated with poor welding. The CNC machine-type also emerges as a neglected variable that needs to be given attention in the selection of process parameters. Although compliance in the tool holder might seem useful, it is shown to have negative consequences as it introduces tool positioning problems.

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