A Study on the Characteristics of Micro Deep Hole Machining Processes

2007 ◽  
pp. 566-571
Author(s):  
Tae Il Seo ◽  
Dong Woo Kim ◽  
Myeong Woo Cho ◽  
Eung Sug Lee
Keyword(s):  
Deep Hole ◽  
Machining Processes ◽  
Hole Machining

A Study on the Characteristics of Micro Deep Hole Machining Processes

2007 ◽  
Vol 364-366 ◽  
pp. 566-571
Author(s):  
Tae Il Seo ◽  
Dong Woo Kim ◽  
Myeong Woo Cho ◽  
Eung Sug Lee
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Printed Circuit Boards ◽  
Hole Drilling ◽  
Deep Hole ◽  
Machining Processes ◽  
Deep Hole Drilling ◽  
Micro Drilling ◽  
Hole Machining

Recently, the trends of industrial products move towards more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is required to perform more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multilayered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. The industries of precision production require smaller holes, high aspect ratio and high speed working for micro deep hole drilling. However the undesirable characteristics of micro drilling is the small signal to noise ratios, wandering motion of drill, high aspect ratio and the increase of cutting force as cutting depth increases. In order to optimize cutting conditions, an experimental study on the characteristics of micro deep hole machining processes using a tool dynamometer was carried out. And additionally, microscope with built-in an inspection monitor showed the relationship between burr in workpieces and chip form of micro drill machining.

scholarly journals Temperature monitoring in the subsurface during single lip deep hole drilling

2020 ◽  
Vol 87 (12) ◽  
pp. 757-767
Author(s):  
Robert Wegert ◽  
Vinzenz Guski ◽  
Hans-Christian Möhring ◽  
Siegfried Schmauder
Keyword(s):  
Cutting Parameters ◽  
Drill Hole ◽  
Machining Process ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Machining Processes ◽  
Deep Hole Drilling ◽  
Feed Force ◽  
Cutting Zone

AbstractThe surface quality and the subsurface properties such as hardness, residual stresses and grain size of a drill hole are dependent on the cutting parameters of the single lip deep hole drilling process and therefore on the thermomechanical as-is state in the cutting zone and in the contact zone between the guide pads and the drill hole surface. In this contribution, the main objectives are the in-process measurement of the thermal as-is state in the subsurface of a drilling hole by means of thermocouples as well as the feed force and drilling torque evaluation. FE simulation results to verify the investigations and to predict the thermomechanical conditions in the cutting zone are presented as well. The work is part of an interdisciplinary research project in the framework of the priority program “Surface Conditioning in Machining Processes” (SPP 2086) of the German Research Foundation (DFG).This contribution provides an overview of the effects of cutting parameters, cooling lubrication and including wear on the thermal conditions in the subsurface and mechanical loads during this machining process. At first, a test set up for the in-process temperature measurement will be presented with the execution as well as the analysis of the resulting temperature, feed force and drilling torque during drilling a 42CrMo4 steel. Furthermore, the results of process simulations and the validation of this applied FE approach with measured quantities are presented.

Deep Hole Honing Based on Squeeze Film Damping Technology

2009 ◽  
Vol 76-78 ◽  
pp. 252-257
Author(s):  
Tian Biao Yu ◽  
Ya Dong Gong ◽  
Wan Shan Wang
Keyword(s):  
Differential Equation ◽  
Experimental Result ◽  
Squeeze Film ◽  
Design Parameters ◽  
Improve Quality ◽  
Deep Hole ◽  
Squeeze Film Damper ◽  
Squeeze Film Damping ◽  
Hole Machining

In order to improve quality of deep hole machining, a new method of deep hole honing based on squeeze film damping technology is put forward. For analysis effect on damper parameters on honing quality, motion differential equation of honing spindle with a squeeze film damper (SFD) is established according to D' Alembert principle and according simulations are studied. Spindle of deep hole honing with a SFD is designed based on the result of simulations and experiments are carried on. Experimental result shows that SFD with reasonable design parameters has excellent damping function to honing spindle, and it can make the vibration of honing spindle reduced 20%～30% and the quality of deep hole machining improved 10%～20%.

Centering deep hole drilling system with three oil films like centering rotating journal with oil films in bearing

2021 ◽  
Vol 73 (6) ◽  
pp. 993-999
Author(s):  
Daguo Yu ◽  
Ming Zhao
Keyword(s):  
Hydrodynamic Lubrication ◽  
Hole Drilling ◽  
The Novel ◽  
Deep Hole ◽  
Drilling Tool ◽  
Content Type ◽  
Hydrodynamic Bearing ◽  
Drilling System ◽  
Oil Films ◽  
Hole Machining

Purpose This study and its centering device with Archimedes spirals designed on hydrodynamic lubrication aims to reduce the deviation of deep holes because the drill tube is long and easy to deviate in deep hole machining. Design/methodology/approach The centering device with Archimedes spirals was designed and fixed between the drilling tool and the drill tube. The wall of the deep hole and the novel centering device formed three wedge-shaped oil films. When the workpiece rotated relative to the centering device, pressure was generated in the oil films; therefore, three oil films supported drilling system as oil films support rotating journal in the full-film hydrodynamic bearing. Findings When the Boring and Trepanning Association (BTA) drilling system was equipped with the centering device, the cutting oil flowed smoothly and carried all the iron chips; the motors run normally; no additional vibration or sound was detected during processing; the surface of the centering device was smooth; and the deviation of the drilled deep hole decreased with a high probability. Originality/value To the best of the authors’ knowledge, no one has designed and made the centering device with Archimedes spirals to reduce the deviation of deep holes in deep hole machining. Three oil films formed by the centering device with Archimedes spirals support drilling system and prevent it from deviating, which has never appeared before and is creative.

Optimal Design of Multi-Edge Cutting Tools for BTA Deep-Hole Machining

1979 ◽  
Vol 101 (2) ◽  
pp. 281-290 ◽  
Author(s):  
V. Latinovic ◽  
R. Blakely ◽  
M. O. M. Osman
Keyword(s):  
Objective Function ◽  
Cutting Force ◽  
Cutting Tools ◽  
Design Procedure ◽  
Preliminary Test ◽  
Cutting Parameters ◽  
Deep Hole ◽  
Cutting Head ◽  
Nonlinear Objective Function ◽  
Hole Machining

The design procedure of optimal multi-edge BTA deep-hole machining tools with unsymmetrically located cutters and preliminary test evidence are presented. Based on a mathematical model of cutting forces in terms of fundamental cutting parameters of the tool, a multivariable, nonlinear objective function was derived and modified to an unconstrained type with bounded decision variables. A numerical, direct search method, accelerated in distance, was selected to minimize the objective function. This procedure insures, on one hand, a predetermined cutting force resultant necessary for tool guidance; on the other hand, it minimizes the variation of cutting edge pressure. A relatively fast computer routine was adapted to provide the optimal tool parameters, which then were used to design cutting head prototypes. Two trepanning heads of three and two cutters were manufactured and tested at production facilities. The test results showed that the cutting force resultant was well predicted in both heads and that they were well guided. Much higher feed rates were possible compared to those achieved with single-edge tools without any loss of hole accuracy straightness or surface finish.

A Study of Deep-Hole Machining of Stainless Steel with Small-Diameter Drill

2012 ◽  
Vol 565 ◽  
pp. 376-381 ◽  
Author(s):  
Yoshiyuki Masuta ◽  
Koichi Okuda ◽  
Hiroo Shizuka ◽  
Masayuki Nunobiki
Keyword(s):  
Stainless Steel ◽  
Thrust Force ◽  
Small Diameter ◽  
Cutting Condition ◽  
Deep Hole ◽  
Shape Accuracy ◽  
Tool Performance ◽  
Deep Depth ◽  
Tool Diameter ◽  
Hole Machining

This paper describes an influence of the cutting condition on the tool performance and the hole shape accuracy in a deep-hole machining of stainless steel with small-diameter drill. The drilling tests were carried out by changing the feed, tool diameter and drill length in order to investigate the appropriate cutting conditions for drilling the holes with deep depth. The results indicate that the increase of the thrust force leads to the buckling of the drill and the work hardening of the workpiece causes the tool failure.

On the Problem of Spiralling in BTA Deep-Hole Machining

1994 ◽  
Vol 116 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Y. B. Gessesse ◽  
V. N. Latinovic ◽  
M. O. M. Osman
Keyword(s):  
Natural Frequency ◽  
Experimental Approach ◽  
Deep Hole ◽  
Boring Bar ◽  
Critical Speeds ◽  
Standard Position ◽  
Boring Tool ◽  
Hole Machining

The phenomenon of spiralling or helical multi-lobe formation in holes, produced by the BTA (Boring and Trepanning Association) machining, is experimentally investigated for the solid boring tool. The causes leading to spiralling are deduced from this investigation. The experimental approach pursued in exploring the problem involved the running of the machine, at analytically predicted critical speeds and observing the reoccurrence of the phenomenon. It has been established that sprialling is caused by defectiveness of the tool (radial oversize of the circle-land with respect to the leading pad around the circumference) and the coincidence of the lateral natural frequency of the boring bar-tool asssembly, with five cycles per revoution of the tool, relative to the workpiece. It has also been established that spiralling occurs only in five lobes for the commercially available BTA-solid tool and is a consequence of the standard position of the circle-land, relative to the leading pad. The trials are repeated a number of times with various workpiece materials, to assert validity of the observations.

Study on Application of SFD for Deep Hole Machining

2006 ◽  
Vol 304-305 ◽  
pp. 450-454
Author(s):  
Tian Biao Yu ◽  
Ya Dong Gong ◽  
J. Liu ◽  
F. Xu ◽  
Wan Shan Wang
Keyword(s):  
Differential Equation ◽  
Experimental Result ◽  
Squeeze Film ◽  
Grinding Wheel ◽  
Deep Hole ◽  
Work Efficiency ◽  
Squeeze Film Damper ◽  
Machining Precision ◽  
Is Design ◽  
Hole Machining

Based on the shortcoming and deficiency of deep hole machining, a grinding wheel spindle with squeeze film damper—SFD is design based on squeeze film damped theory. The motion differential equation of SFD grinding wheel spindle is constituted according to D’ Ale mbert principle，and a lot of simulated research has been carried out about the locus of grinding wheel spindle affect by SFD. Founded on the simulated result, the SFD grinding wheel spindle of internal grinder have designed, and the grinding experiments have been performed. Experimental result indicate that the rationality of design for SFD can make the vibration of the grinding wheel spindle reduce 25% , and make machining precision of hole improve 20% , make work efficiency of the grinder raise 15%.

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