Influence of Cutting Compound on Critical Cut Depth of Glass BK7

2013 ◽  
Vol 579-580 ◽  
pp. 97-100
Author(s):  
Peng Jia

In diamond cutting of optical glasses, the magnitude of critical depth of cut for brittle-ductile transition is an important factor affecting the machinability of the work material in terms of production rate and surface quality. In this work, scratching tests with increasing depths of cut were conducted on glass BK7 to evaluate the influence of the cutting fluid properties on the critical depth of cut. Boric acid solutions of different concentrations were selected as cutting fluids in the tests. The resulting scratches were examined utilizing a white light interferometer and the values of the critical depth of cut were determined based on the observations of the micro-morphology of the scratch surfaces produced. Experimental results indicated that compared with the process without cutting fluid action, the critical depth of cut in diamond cutting of glass BK7 can be increased by using boric acid solution as the cutting fluid.

2013 ◽  
Vol 770 ◽  
pp. 230-233 ◽  
Author(s):  
Peng Jia

In diamond cutting of optical glasses, the magnitude of critical depth of cut for brittle-ductile transition is an important factor affecting the machinability of the work material in terms of production rate and surface quality. In this work, scratching tests with increasing depths of cut were conducted on glass BK7 to evaluate the influence of the cutting fluid properties on the critical depth of cut. Boric acid solutions of different concentrations were selected as cutting fluids in the tests. The resulting scratches were examined utilizing a white light interferometer and the values of the critical depth of cut were determined based on the observations of the micro-morphology of the scratch surfaces produced. Experimental results indicated that compared with the process without cutting fluid action, the critical depth of cut in diamond cutting of glass BK7 can be increased by using boric acid solution as the cutting fluid.


2013 ◽  
Vol 589-590 ◽  
pp. 480-484 ◽  
Author(s):  
Peng Jia

In diamond cutting of optical glasses, the magnitude of critical depth of cut for brittle-ductile transition is an important factor affecting the machinability of the work material in terms of production rate and surface quality. In this work, scratching tests with increasing depths of cut were conducted on glass BK7 to evaluate the influence of the cutting fluid properties on the critical depth of cut. Boric acid solutions of different concentrations were selected as cutting fluids in the tests. The resulting scratches were examined utilizing a white light interferometer and the values of the critical depth of cut were determined based on the observations of the micro-morphology of the scratch surfaces produced. Experimental results indicated that compared with the process without cutting fluid action, the critical depth of cut in diamond cutting of glass BK7 can be increased by using boric acid solution as the cutting fluid.


2010 ◽  
Vol 431-432 ◽  
pp. 126-129 ◽  
Author(s):  
Ming Zhou ◽  
Peng Jia ◽  
Min Li

In diamond cutting of optical glasses, the magnitude of critical depth of cut for brittle-ductile transition is an important factor affecting the machinability of the work material in terms of production rate and surface quality. In this work, scratching tests with increasing depths of cut were conducted on glass BK7 to evaluate the influence of the cutting fluid properties on the critical depth of cut. Boric acid solutions of different concentrations were selected as cutting fluids in the tests. The resulting scratches were examined utilizing a white light interferometer and the values of the critical depth of cut were determined based on the observations of the micro-morphology of the scratch surfaces produced. Experimental results indicated that compared with the process without cutting fluid action, the critical depth of cut in diamond cutting of glass BK7 can be increased by using boric acid solution as the cutting fluid.


2009 ◽  
Vol 626-627 ◽  
pp. 47-52 ◽  
Author(s):  
Ming Zhou ◽  
P. Jia ◽  
M. Li

Glass possesses poor machinability in diamond cutting due to its high hardness and high brittleness. In order to investigate the effect of cutting fluids on the machinability of glass, this paper first conducted soda-lime indentation experiment, and then examined the resulting indentation by optical microscope. Based on this, turning tests were carried out to evaluate the influence of the cutting fluid properties on the machinability of glass. Boric acid solutions were selected as cutting fluids in the tests. The surface processing quality of soda-lime was assessed based on the observations of the micro- morphology of the turned surfaces utilizing AFM. Experimental results indicated that compared with the process without cutting fluid action, the machinability of glass soda-lime can be improved by using boric acid solution as the cutting fluid.


2013 ◽  
Vol 589-590 ◽  
pp. 194-197 ◽  
Author(s):  
Peng Jia

For the technology of diamond cutting of optical glass, the machinability of glass is poor, which hindering the practical application of this technology. In order to investigate and ameliorate the machinability of glass, and achieve optical parts with the satisfied surface quality and dimensional accuracy, this paper first conducted SF6 indentation experiment by Vickers microhardness instrument, and then the scratching tests with increasing depths of cut were conducted on glass SF6 to evaluate the influence of the cutting fluid properties on the machinability of glass. Based on this, turning tests were carried out, and the surface quality of SF6 was assessed based on the detections of the machined surfaces roughness. Experimental results indicated that compared with the process of dry cutting, the machinability of glass SF6 can be improved by using the cutting fluid


Author(s):  
Jinyang Ke ◽  
Xiao Chen ◽  
Jianguo Zhang ◽  
Changlin Liu ◽  
Guoqing Xu ◽  
...  

Abstract Laser-assisted diamond cutting is a promising process for machining hard and brittle materials. A deep knowledge of material removal mechanism and attainable surface integrity are crucial to the development of this new technique. This paper focuses on the application of laser-assisted diamond cutting to single crystal silicon to investigate key characteristics of this process. The influence of laser power on the ductile machinability of single crystal silicon, in terms of the critical depth of cut for ductile-brittle transition in laser-assisted diamond cutting, is investigated quantitatively using a plunge-cut method. The experimental results reveal that this process can enhance the silicon’s ductility and machinability. The critical depth of cut has been increased by up to 330% with laser assistance, and its degree generally increases with the increase of laser power. The cross-sectional transmission electron microscope observation results indicate that laser-assisted diamond cutting is able to realize the subsurface damage free processing of single crystal silicon. In order to verify the ability of the laser-assisted diamond cutting to improve the surface quality, the face turning tests are also carried out. A significant improvement of surface quality has been obtained by laser-assisted diamond cutting: Sz (maximum height) has been reduced by 85% and Sa (arithmetical mean height) has been reduced by 45%.


Author(s):  
Hao Wu ◽  
Shreyes N. Melkote

The ductile-to-brittle cutting mode transition in single grit diamond scribing of monocrystalline silicon is investigated in this paper. Specifically, the effects of scriber tip geometry, coefficient of friction, and external hydrostatic pressure on the critical depth of cut associated with ductile-to-brittle transition and crack generation are studied via an eXtended Finite Element Method (XFEM) based model, which is experimentally validated. Scribers with a large tip radius are shown to produce lower tensile stresses and a larger critical depth of cut compared with scribers with a sharp tip. Spherical tipped scribers are shown to generate only surface cracks, while sharp tipped scribers (conical, Berkovich and Vickers) are found to create large subsurface tensile stresses, which can lead to nucleation of subsurface median/lateral cracks. Lowering the friction coefficient tends to increase the critical depth of cut and hence the extent of ductile mode cutting. The results also show that larger critical depth of cut can be obtained under external hydrostatic pressure. This knowledge is expected to be useful in optimizing the design and application of the diamond coated wire employed in fixed abrasive diamond wire sawing of photovoltaic silicon wafers.


2007 ◽  
Vol 339 ◽  
pp. 395-399 ◽  
Author(s):  
Ming Zhou ◽  
X.D. Liu ◽  
S.N. Huang

Soda-lime glass is a typical brittle material, which is difficult to realize ductile-regime machining by using conventional cutting technology due to the extremely small critical depth of cut. In this work, the micro-deformation characteristics of this kind of materials were analyzed by micro indentation. Ultrasonic vibration assisted diamond cutting was performed in order to investigate the effect of tool vibration on material removal process and surface quality. The profiles of cut surfaces were measured and compared with those obtained by conventional diamond cutting. Real depths of cut in ultrasonic vibration cutting correspond well with the nominal ones. The change in the tribology of the cutting process as well as the alteration of the deformation mechanism of the work material might be responsible for the reduction in tool wear in vibration cutting.


2021 ◽  
Author(s):  
Mohammad Rasheed Khan ◽  
Guenther Glatz ◽  
Devon Chikonga Gwaba ◽  
Gallyam Aidagulov

Abstract More than two decades have passed since the introduction of the scratch testing method for rock strength determination. The test method typically involves dragging a rigid-shaped cutter across the rock surface at a fixed cutting depth. This depth determines the failure mechanism of the rock, ductile for shallow depths and brittle for deeper. In the ductile mode, intrinsic specific energy is primarily a measure of the unconfined-compressive-strength (UCS), which is pivotal for rate of penetration (ROP) during drilling and for borehole stability analysis. On the contrary, brittle failure can lead to permanent core damage and is usually not desired as it impacts interpretation of the scratch testing results. Consequently, it is imperative to identify the critical depth, and at which transition from ductile to brittle failure occurs which will help optimize rock testing and tool designs. In this study, a novel methodology is proposed utilizing micro-computed tomography (CT) imaging to determine critical depth through morphological analysis of scratch test cuttings. Scratch tests are carried out on Indiana limestone core samples with the cutter-rock interaction geometry characterized by a cutter width of 10mm and a back-rake angle of 15°. The sample is scratched in the range of 0.05mm to 0.40mm with increments of 0.05mm. Scratch powder is carefully collected after each scratch increment and stored for further analysis. This powder is then loaded into slim rubber tubes and imaged at a high resolution of 1 µm with a helical micro-CT scanner. The scans are then reconstructed using a computer program to initiate the visualization of individual grains from each cutter depth including evaluation of grain morphologies. Finally, the results from this morphological analysis are corroborated and compared with three other methods: force response analysis, force inflection point analysis, and the size effect law (SEL). Based on shape analysis, it was found that the transition from ductile to brittle regime occurs at a depth of 0.25mm. Elongation and appearance of the enhanced degree of angularity of the grains as the depth of cut (DOC) increases past 0.25mm was observed. Moreover, large grain sizes were detected and are representative of formation of chips (typical brittle regime response). Furthermore, it is illustrated that the image analysis helps eliminate the ambiguity of force signal analysis and in combination can aid in the critical depth of cut determination. The other methods involving force alone and the SEL are not able to pin-point onset of brittle regime. Using a similar methodology, creation of a database for various rock types is recommended to develop a guide for the depth of cut selection during scratch testing. This novel methodology utilizing micro-CT analysis and comparative study with other techniques will put in place an accurate strategy to determine the critical depth of cut when designing rock scratch testing programs.


2008 ◽  
Vol 375-376 ◽  
pp. 206-210
Author(s):  
Hui Ping Zhang ◽  
Zhen Jia Li ◽  
Er Liang Liu ◽  
Guo Liang Wei

This paper deals with chip breaking behaviour of 3-D complex groove inserts in machining carbon constructional steel-45 steel at high cutting speeds .Cutting experiments were performed at eleven different cutting speeds. Firstly, the results showed that by increasing cutting speeds, the changes of the critical feedrate and chip breaking scopes at high cutting speeds machining with 3-D complex groove inserts were nonlinear and not monotonous function relations. Then, mathematic models were built. Secondly, the results showed that the critical depth of cut was a constant value at various cutting speeds. And, the curves of the critical depth of cut were perpendicular lines. For this purpose, the critical depth of cut mathematic model has been built. The study above lays a theory and basis for future investigation of the mechanism of chip breaking with 3-D groove insert in high speed machining.


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