The Effects of Resharpening Accuracy on Drill Failure and Hole Straightness in High Aspect Ratio Gundrilling of Inconel-718

2012 ◽  
Vol 565 ◽  
pp. 388-393
Author(s):  
Keng Soon Woon ◽  
Shigeyuki Kanno ◽  
Kui Liu
Keyword(s):  
Pilot Study ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Inconel 718 ◽  
Failure Modes ◽  
Drilling Process ◽  
The Stability ◽  
Drilling Conditions ◽  
High Degree

This paper presents a pilot study on the consistency of high aspect ratio gundrilling of Inconel-718 that involves the drilling of three holes of 8mm in diameter and 1600mm in depth, under constant drilling conditions. But high degree of straightness variations among these holes indicates that critical drill geometries could not be accurately regenerated through the drill resharpening operation. As a result, vast variability is introduced to the process which has severe detrimental effects on the stability of the drilling process and degradation and failure modes of the drill as well the straightness accuracy of the holes.

scholarly journals Impact of the Deionized Water on Making High Aspect Ratio Holes in the Inconel 718 Alloy with the Use of Electrical Discharge Drilling

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1476 ◽  
Author(s):  
Magdalena Machno ◽  
Rafał Bogucki ◽  
Maciej Szkoda ◽  
Wojciech Bizoń
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Inconel 718 ◽  
Electrical Discharge ◽  
Initial Temperature ◽  
Deionized Water ◽  
Working Fluid ◽  
Inconel 718 Alloy ◽  
Electrical Discharge Drilling ◽  
Side Gap

Nickel-based superalloys are being increasingly applied to manufacture components in the aviation industry. The materials are classified as difficult-to-machine using conventional methods. Nowadays, manufacturing techniques are needed to drill high aspect ratio holes of above 20:1 (depth-to-diameter ratio) in these materials. One of the most effective methods of making high-aspect-ratio holes is electrical discharge drilling (EDD). While drilling high aspect ratio holes, a crucial issue is the flushing of the gap area and the evacuation of the erosion products. The use of deionized water as the dielectric fluid in the EDD offers a considerable potential. This paper includes an analysis of the influence of the machining parameters (pulse time, current amplitude and discharge voltage) on the process performance (drilling speed, linear tool wear, taper angle, hole’s aspect ratio, side gap thickness), during the EDD with the use of deionized water in the Inconel 718 alloy. The obtained through holes were subjected to the extended analysis. The impact of the initial working fluid temperature and pressure on the conditions of the flow through the electrode channel was also subjected to the analysis. The deionized water properties were changed by applying an initial temperature. Based on the results of an analysis of the previous research, the EDD of the through holes was performed for a pre-set initial temperature (~313.15 °K) and initial pressure of the working fluid (8 MPa) and selected process parameters. An analysis of the results indicates increasing of hole’s aspect ratio by about 15% (above 30), decreasing the side gap thickness by about 40% and enhanced surface integrity.

A Two-Step Spacer Etch for High-Aspect-Ratio Gate Stack Process

2000 ◽  
Vol 611 ◽  
Author(s):  
Chien Yu ◽  
Rich Wise ◽  
Anthony Domenicucci
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Gate Stack ◽  
Methyl Fluoride ◽  
Thermal Oxide ◽  
Profile Control ◽  
The Stability ◽  
Better Than

ABSTRACTA highly selective nitride etch was developed for gate stack spacer process in advanced memory programs. Based on methyl fluoride chemistry with better than 8:1 selectivity of nitride:oxide, this process exhibits minimal erosion to the underlying RTO thermal oxide for consistent diffusion ion-implant control. As the groundrule changed to 0.175um and below, a two-step etch scheme was employed to maintain the profile control in high-aspect-ratio structures. The stability and repeatability of the process is demonstrated in the SPC chart of the post etch FTA site measurement.

Pulsed Injector Induced Mixing in High Aspect Ratio Microchannel Flow

2003 ◽  
Author(s):  
B. Siripoorikan ◽  
J. A. Liburdy ◽  
D. V. Pence
Keyword(s):  
Aspect Ratio ◽  
Flow Rate ◽  
High Aspect Ratio ◽  
Rate Ratio ◽  
Main Channel ◽  
Flow Rate Ratio ◽  
Passive Mixing ◽  
Mixing Techniques ◽  
Biochemical Production ◽  
High Degree

Micro-fluid mixing is an important aspect of many of the various micro-fluidic systems used in biochemical production, biomedical industries, microenergy systems and some electronic devices. Active or highly effective passive mixing techniques are often required. In this study, two pulsed injectors are used to actively enhance mixing in a high aspect ratio microchannel (125 μm deep and 1 mm wide). The main channel has two adjacent flowing streams with 100% dye and 0% dye concentrations, respectively. Two injectors (125 μm deep and 250 μm wide) are located on opposite sides of the channel and off-set in the downstream direction. A dye solution is used to map local mixing throughout the channel by measuring concentration variations as a function of both space and time. Images of the concentration variations within the channel are used to quantify mixing. It is shown that there is a high degree of repeatability of concentration distribution as a function of phase of the pulsing cycle. The flow rate ratio between the injectors and main channel is found to be the most influential parameter on overall mixing, and evidence of an optimal flow rate ratio and frequency is presented. A nondimensional correlation is presented that could be used to predict the level of mixing for the conditions studied.

scholarly journals Using Stereolithographic Printing to Manufacture Monolithic Microfluidic Devices with an Extremely High Aspect Ratio

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3750
Author(s):  
Pin-Chuan Chen ◽  
Po-Tsang Chen ◽  
Tuan Ngoc Anh Vo
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Dimensional Accuracy ◽  
Microfluidic Devices ◽  
Oxygen Inhibition ◽  
Dimensional Precision ◽  
Inner Surface ◽  
Inhibition Process ◽  
High Degree

Stereolithographic printing (SL) is widely used to create mini/microfluidic devices; however, the formation of microchannels smaller than 500 μm with good inner surface quality is still challenging due to the printing resolution of current commercial printers and the z-overcure error and scalloping phenomena. In the current study, we used SL printing to create microchannels with the aim of achieving a high degree of dimensional precision and a high-quality microchannel inner surface. Extensive experiments were performed and our results revealed the following: (1) the SL printing of microchannels can be implemented in three steps including channel layer printing, an oxygen inhibition process, and roof layer printing; (2) printing thickness should be reduced to minimize the scalloping phenomenon, which significantly improves dimensional accuracy and the quality of inner microchannel surfaces; (3) the inclusion of an oxygen inhibition step is a critical and efficient approach to suppressing the z-overcure error in order to eliminate the formation of in-channel obstructions; (4) microchannels with an extremely high aspect ratio of 40:1 (4000 μm in height and 100 μm in width) can be successfully manufactured within one hour by following the three-step printing process.

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