Influence of Ultrasonic Assistance on Material Removal Mechanism of Hard and Brittle Materials Based on Single-Point Scratch

2011 ◽  
Vol 487 ◽  
pp. 413-418 ◽  
Author(s):  
Feng Jiao ◽  
Bo Zhao
Keyword(s):  
Material Removal ◽  
Single Point ◽  
Brittle Materials ◽  
Shielding Effect ◽  
Depth Of Cut ◽  
Cutting Depth ◽  
Critical Cutting Depth ◽  
Material Hardness ◽  
Ultrasonic Assisted ◽  
Hard And Brittle Materials

In order to deeply study the influence of ultrasonic assistance on material removal characteristics of hard and brittle materials, a series of ultrasonic assisted single-point scratch experiments have been carried out in this paper. Experimental results show that the assisted ultrasonic vibration is benefit to increase the critical cutting depth and enlarge the ductile regime of material removal. The main reason can be explained as the influences of blank cutting phenomenon, the decrease of the normal cutting force under the same depth of cut, the decrease of the material hardness under ultrasonic excitation and the shielding effect of lateral crack.

A Study of Ultrasonically Assisted Fly Cutting for High Precision Machining Hard Brittle Materials

2010 ◽  
Vol 126-128 ◽  
pp. 252-257
Author(s):  
Keisuke Hara ◽  
Hiromi Isobe ◽  
Shuichi Chiba ◽  
Keiko Abe
Keyword(s):  
Brittle Materials ◽  
Hot Press ◽  
Cutting Depth ◽  
Advanced Ceramics ◽  
Fly Cutting ◽  
Critical Cutting Depth ◽  
Ductile Mode ◽  
Ultrasonic Assisted ◽  
Ductile Mode Cutting ◽  
Glass Lenses

This paper describes ultrasonically assisted fly cutting for finishing advanced ceramics for hot-press dies used to fabricate glass lenses. Fly cutting can perform shallow machining, which realizes ductile-mode cutting of hard, brittle materials. Ultrasonically assisted machining can increase the critical cutting depth (i.e., the maximum cutting depth for ductile-mode machining of a surface). The technique proposed in this paper combines both techniques and enables precise finishing of advanced ceramics at a high machining efficiency. Ultrasonic assisted fly cutting was found to reduce tool fracture and improve the finished surface quality compared with conventional fly cutting.

Tool Wear and Form Accuracy in Ultrasonic-Assisted Milling of Soda-Lime Glass

2018 ◽  
Vol 786 ◽  
pp. 206-214
Author(s):  
Yasmine El-Taybany ◽  
Mohab Hossam ◽  
Hassan El-Hofy
Keyword(s):  
Tool Wear ◽  
Brittle Materials ◽  
Soda Lime ◽  
Machining Process ◽  
Depth Of Cut ◽  
Soda Lime Glass ◽  
Form Accuracy ◽  
Ultrasonic Assisted ◽  
Hard And Brittle Materials ◽  
Vibration Assistance

Machining of hard and brittle materials is inherently involved with tool wear, which influences the dimensional and form accuracy of the machined product. Ultrasonic-assisted machining process is suitable for hard-to-cut materials such as ceramics, glass, and metal matrix composites, etc. In the current study, the mechanism of tool wear is investigated during ultrasonic-assisted milling of soda-lime glass as one of hard and brittle materials. Ultrasonic-Assisted Milling (UAM) combines the material removal mechanism of grinding and the milling kinematics with ultrasonic assistance. The effect of different process parameters, i.e. feed rate, depth of cut, cutting fluid, and ultrasonic vibration assistance on the tool wear behavior are investigated. Form accuracy of the machined slots is also investigated. The results showed that UAM produces less tool wear than conventional milling (CM). However, CM gives less error in the slot dimensions than UAM.

Critical Depth of Cut and Specific Cutting Energy of a Microscribing Process for Hard and Brittle Materials

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Jiunn-Jyh Junz Wang ◽  
Yong-Yuan Liao
Keyword(s):  
Brittle Materials ◽  
Depth Of Cut ◽  
Specific Cutting Energy ◽  
Critical Depth ◽  
Cutting Depth ◽  
Crystal Silicon ◽  
Cutting Energy ◽  
Process Characteristics ◽  
Hard And Brittle Materials ◽  
Critical Depth Of Cut

This paper investigated the scribing process characteristics of the hard and brittle materials including single crystal silicon, STV glass, and sapphire substrate. Under various cutting angles, major process characteristics are examined including the groove geometry, specific cutting energy, and critical depth of cut at the onset of ductile-to-brittle cutting transition. As the cutting depth increases, groove geometry clearly reveals the ductile-to-brittle transition from the plastic deformation to a brittle fracture state. The material size effect in the ductile region as well as the transition in scribing behavior is well reflected by change in the specific cutting energy. Further, it is shown that the change of specific cutting energy as a function of the cutting depth can serve as a criterion for estimating the critical depth of cut. Such estimated critical depth of cut is confirmed by measurement from a 3D confocal microscope. The critical depths of cut for these hard materials are found to be between 0.1μm and 0.5μm depending on the materials and cutting angles.

Werkzeuge der ultraschallunterstützten Bearbeitung*/Modelling of an Actorsystem - Development of a tool for ultrasonic assisted machining with an axial-tangential vibration vector

2018 ◽  
Vol 108 (01-02) ◽  
pp. 53-57
Author(s):  
K. Drewle ◽  
T. Stehle ◽  
H: Möhring
Keyword(s):  
Contact Zone ◽  
Brittle Materials ◽  
Wird Eine ◽  
Alternative Method ◽  
Ultrasonic Assisted ◽  
Ultrasonic Assisted Machining ◽  
Hard And Brittle Materials ◽  
Feed Axis

Die schwingungsunterstützte Bearbeitung hat sich bereits bei der Zerspanung von hartspröden Werkstoffen mit einer einachsigen Schwingung in der Kontaktzone bewährt. Untersuchungen zu schwingungsunterstützten Bohrprozessen beschränken sich bisher auf eine Schwingungserzeugung, die entlang der Vorschubachse ausgerichtet ist. Für alternative Schwingungsrichtungen fehlt in erster Linie die geeignete Aktorik. In diesem Beitrag wird eine alternative Methode zur Erzeugung einer axial-tangentialen Schwingung in der Kontaktzone untersucht.   Ultrasonic assisted machining with uniaxial vibration is a well-proven process for machining hard and brittle materials. Existing investigations of vibration assisted drilling and boring processes so far are limited to an oscillation along the feed axis, which primarily due to nonexistent actuators. This contribution will present investigations into an alternative method for creating axial-tangential vibrations in the tool contact zone.

Effects of Alpha-Cellulose Supply on the Working Life of MCF Slurry in MCF Polishing

2020 ◽  
Author(s):  
Yuta Nonaka ◽  
Mitsuyoshi Nomura ◽  
Tatsuya Fujii ◽  
Tsunehisa Suzuki ◽  
Yongbo Wu
Keyword(s):  
High Precision ◽  
Single Point ◽  
Brittle Materials ◽  
Surface Damage ◽  
Diamond Turning ◽  
Optical Systems ◽  
Smart Devices ◽  
Tool Marks ◽  
Hard And Brittle Materials ◽  
Inspection Systems

Abstract High precision surfaces exhibit prominent capabilities for enhancing the imaging quality, expanding the visibility of equipment, simplifying structures, and reducing total costs of optical systems. Hence, they are regarded as essential optical surfaces for replacing traditional elements to modify optical systems, including space systems, optical inspection systems, and smart devices. Single point diamond turning (SPDT) and ultra-precision grinding have been adopted preliminarily to manufacture high-quality elements. However, these processes create sub-surface damage and tool marks on the work surface. To meet performance requirements, polishing is critical for post-processing to improve the quality of the products. MCF (Magnetic Compound Fluid) polishing, which is one of polishing methods using magnetic fields, is a processing method for finishing hard and brittle materials with high accuracy. Previous research has shown that MCF polishing is effective for hard and brittle materials. However, despite the high cost of the magnetic fluid that is a component of the MCF slurry, the MCF slurry used for polishing has been discarded. Another major issue was that unused MCF slurry could not be used due to drying. The purpose of this study is to recycle MCF slurry to solve this problem, and to develop high precision finishing technology. Therefore, in this study, a novel MCF polishing method using ultrasonic atomization is proposed, and the effects of α-cellulose on the MCF polishing are investigated. In addition, in order to make it possible to reuse the MCF slurry, In addition, experiments are conducted to enable reuse of MCF slurry.

Analytical Elastic–Plastic Cutting Model for Predicting Grain Depth-of-Cut in Ultrafine Grinding of Silicon Wafer

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Bin Lin ◽  
Ping Zhou ◽  
Ziguang Wang ◽  
Ying Yan ◽  
Renke Kang ◽  
...  
Keyword(s):  
Silicon Wafer ◽  
Elastic Recovery ◽  
Brittle Materials ◽  
Analytical Models ◽  
Depth Of Cut ◽  
Ultrafine Grinding ◽  
Hard And Brittle Materials ◽  
Predominant Factor ◽  
Improved Model ◽  
Cutting Model

Grain depth-of-cut, which is the predominant factor determining the surface morphology, grinding force, and subsurface damage, has a significant impact on the surface quality of the finished part made of hard and brittle materials. When the existing analytical models are used to predict the gain depth-of-cut in ultra-precision grinding process of silicon wafer, the results obtained become unreasonable due to an extremely shallow grain depth-of-cut, which is inconsistent with the theory of the contact mechanics. In this study, an improved model for analyzing the grain depth-of-cut in ultra-fine rotational grinding is proposed, in which the minimum grain depth-of-cut for chip formation, the equivalent grain cutting tip radius, elastic recovery deformation in cutting process, and the actual number of effective grains are considered in the prediction of the ultrafine rotational grinding of brittle materials. The improved model is validated experimentally and shows higher accuracy than the existing model. Furthermore, the sensitivity of the grain depth-of-cut to three introduced factors is analyzed, presenting the necessity of the consideration of these factors during the prediction of grain depth-of-cut in ultrafine grinding.

scholarly journals Effect of Thermal Softening on Anisotropy and Ductile Mode Cutting of Sapphire Using Micro-Laser Assisted Machining

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Hossein Mohammadi ◽  
John A. Patten
Keyword(s):  
Removal Rate ◽  
Brittle Materials ◽  
Single Crystal Silicon ◽  
Thermal Softening ◽  
Depth Of Cut ◽  
Crystal Silicon ◽  
Ductile Mode ◽  
Hard And Brittle Materials ◽  
Fracture Damage ◽  
Diamond Cutting Tool

Ceramics and semiconductors have many applications in optics, micro-electro-mechanical systems, and electronic industries due to their desirable properties. In most of these applications, these materials should have a smooth surface without any surface and subsurface damages. Avoiding these damages yet achieving high material removal rate in the machining of them is very challenging as they are extremely hard and brittle. Materials such as single crystal silicon and sapphire have a crystal orientation or anisotropy effect. Because of this characteristic, their mechanical properties vary significantly by orientation that makes their machining even more difficult. In previous works, it has been shown that it is possible to machine brittle materials in ductile mode. In the present study, scratch tests were accomplished on the monocrystal sapphire in four different perpendicular directions. A laser is transmitted to a diamond cutting tool to heat and soften the material to either enhance the ductility, resulting in a deeper cut, or reducing brittleness leading to decreased fracture damage. Results such as depth of cut and also nature of cut (ductile or brittle) for different directions, laser powers, and cutting loads are compared. Also, influence of thermal softening on ductile response and its correlation to the anisotropy properties of sapphire is investigated. The effect of thermal softening on cuts is studied by analyzing the image of cuts and verifying the depth of cuts which were made by using varying thrust load and laser power. Macroscopic plastic deformation (chips and surface) occurring under high contract pressures and high temperatures is presented.

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