scholarly journals Precision Drilling of Ceramic-Coated Components With Abrasive-Waterjets

1991 ◽  
Author(s):  
M. Hashish ◽  
J. Whalen
Keyword(s):  
Small Diameter ◽  
Aircraft Engine ◽  
Hole Drilling ◽  
Hole Quality ◽  
Barrier Coating ◽  
Drilling Parameters ◽  
Abrasive Waterjets ◽  
Engine Testing ◽  
Engine Components ◽  
Accuracy And Repeatability

This paper addresses an experimental investigation on the feasibility of using abrasive-waterjets (AWJs) for the precision drilling of small-diameter holes in advanced aircraft engine components. These components are sprayed with ceramic thermal barrier coating (TBC), and the required holes are typically 0.025 inch in diameter with a drilling angle of 25°. The parameters of the AWJ were varied to study their effects on both quantitative and qualitative hole drilling parameters. The unique techniques of assisting the abrasive feed process, ramping the waterjet pressure during drilling, and varying the jet dwell time after piercing were effectively implemented to control hole quality and size. The results of the experiments indicate the accuracy and repeatability of the AWJ technique in meeting the air flow and hole size requirements. Production parts were drilled for prototype engine testing.

Precision Drilling of Ceramic-Coated Components With Abrasive-Waterjets

1993 ◽  
Vol 115 (1) ◽  
pp. 148-154 ◽  
Author(s):  
M. Hashish ◽  
J. Whalen
Keyword(s):  
Small Diameter ◽  
Aircraft Engine ◽  
Hole Drilling ◽  
Hole Quality ◽  
Barrier Coating ◽  
Drilling Parameters ◽  
Abrasive Waterjets ◽  
Engine Testing ◽  
Engine Components ◽  
Accuracy And Repeatability

This paper addresses an experimental investigation on the feasibility of using abrasive-waterjets (AWJs) for the precision drilling of small-diameter holes in advanced aircraft engine components. These components are sprayed with ceramic thermal barrier coating (TBC), and the required holes are typically 0.025 in. in diameter with a drilling angle of 25 deg. The parameters of the AWJ were varied to study their effects on both quantitative and qualitative hole drilling parameters. The unique techniques of assisting the abrasive feed process, ramping the waterjet pressure during drilling, and varying the jet dwell time after piercing were effectively implemented to control hole quality and size. The results of the experiments indicate the accuracy and repeatability of the AWJ technique in meeting the air flow and hole size requirements. Production parts were drilled for prototype engine testing.

scholarly journals Analyzing the Effects of the Kinematic System on the Quality of Holes Drilled in 42CrMo4 + QT Steel

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4046
Author(s):  
Mateusz Bronis ◽  
Edward Miko ◽  
Lukasz Nowakowski
Keyword(s):  
Cutting Speed ◽  
Hole Drilling ◽  
Internal Cooling ◽  
Hole Quality ◽  
The Third ◽  
Kinematic System ◽  
Turning Center ◽  
Dimensional Errors ◽  
The Relationship

This article discusses the relationship between the kinematic system used in drilling and the quality of through-holes. The drilling was done on a CTX Alpha 500 universal turning center using a TiAlN-coated 6.0 mm drill bit with internal cooling, mounted in a driven tool holder. The holes were cut in cylindrical 42CrMo4 + QT steel samples measuring 30 mm in diameter and 30 mm in length. Three types of hole-drilling kinematic systems were considered. The first consisted of a fixed workpiece and a tool performing rotary (primary) and linear motions. In the second system, the workpiece rotated (primary motion) while the tool moved linearly. In the third system, the workpiece and the tool rotated in opposite directions; the tool also moved linearly. The analysis was carried out for four output parameters characterizing the hole quality (i.e., cylindricity, straightness, roundness, and diameter errors). The experiment was designed using the Taguchi approach (orthogonal array). ANOVA multi-factor statistical analysis was used to determine the influence of the input parameters (cutting speed, feed per revolution and type of kinematic system) on the geometrical and dimensional errors of the hole. From the analysis, it is evident that the kinematic system had a significant effect on the hole roundness error.

scholarly journals Effect of Twist Drill Geometry and Drilling Parameters on Hole Quality in Single-Shot Drilling of CFRP/Al7075-T6 Composite Stack

2021 ◽  
Vol 5 (7) ◽  
pp. 189
Author(s):  
Muhammad Hafiz Hassan ◽  
Jamaluddin Abdullah ◽  
Gérald Franz ◽  
Chim Yi Shen ◽  
Reza Mahmoodian
Keyword(s):  
Feed Rate ◽  
Thrust Force ◽  
Critical Dimension ◽  
Helix Angle ◽  
Single Shot ◽  
Twist Drill ◽  
Hole Quality ◽  
Drilling Parameters ◽  
Industry Practice ◽  
Maximum Thrust

Drilling two different materials in a layer, or stack-up, is being practiced widely in the aerospace industry to minimize critical dimension mismatch and error in the subsequent assembly process, but the compatibility of the drill to compensate the widely differing properties of composite is still a major challenge to the industry. In this paper, the effect of customized twist drill geometry and drilling parameters are being investigated based on the thrust force signature generated during the drilling of CFRP/Al7075-T6. Based on ANOVA, it is found that the maximum thrust force for both CFRP and Al7075-T6 are highly dependent on the feed rate. Through the analysis of maximum thrust force, supported by hole diameter error, hole surface roughness, and chip formation, it is found that the optimum tool parameters selection includes a helix angle of 30°, primary clearance angle of 6°, point angle of 130°, chisel edge angle of 30°, speed of 2600 rev/min and feed rate of 0.05 mm/rev. The optimum parameters obtained in this study are benchmarked against existing industry practice of the capability to produce higher hole quality and efficiency, which is set at 2600 rev/min for speed and 0.1 mm/rev for feed rate.

scholarly journals Repair of Precision Castings Made of the Inconel 713C Alloy

2017 ◽  
Vol 17 (3) ◽  
pp. 210-216
Author(s):  
K. Łyczkowska ◽  
J. Adamiec
Keyword(s):  
Model Test ◽  
Aircraft Engine ◽  
Casting Defects ◽  
Exhaust Gas ◽  
Plasma Arc ◽  
Nickel Based Superalloy ◽  
Melted Zone ◽  
Base Materials ◽  
Inconel 713C ◽  
Engine Components

Abstract Inconel 713C precision castings are used as aircraft engine components exposed to high temperatures and the aggressive exhaust gas environment. Industrial experience has shown that precision-cast components of such complexity contain casting defects like microshrinkage, porosity, and cracks. This necessitates the development of repair technologies for castings of this type. This paper presents the results of metallographic examinations of melted areas and clad welds on the Inconel 713C nickel-based superalloy, made by TIG, plasma arc, and laser. The cladding process was carried out on model test plates in order to determine the technological and material-related problems connected with the weldability of Inconel 713C. The studies included analyses of the macro- and microstructure of the clad welds, the base materials, and the heat-affected zones. The results of the structural analyses of the clad welds indicate that Inconel 713C should be classified as a low-weldability material. In the clad welds made by laser, cracks were identified mainly in the heat-affected zone and at the melted zone interface, crystals were formed on partially-melted grains. Cracks of this type were not identified in the clad welds made using the plasma-arc method. It has been concluded that due to the possibility of manual cladding and the absence of welding imperfections, the technology having the greatest potential for application is plasma-arc cladding.

Effect of cooling method on small diameter blind-hole drilling of new β-type dental Ti-Zr-Nb alloy

2020 ◽  
Vol 59 ◽  
pp. 421-431
Author(s):  
Bo Chen ◽  
Feixiang Xiong ◽  
Hongqun Tang ◽  
Liang He ◽  
Shanshan Hu
Keyword(s):  
Small Diameter ◽  
Hole Drilling ◽  
Blind Hole ◽  
Cooling Method
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