Ductile regime machining is an alternative method for polishing of brittle materials to obtain a high quality surface finish by a ductile or plastic material removal process. Hence, there is a growing interest to study ductile regime machining over several decades.

Mar 29, 2006· Diamond turning, precision grinding, ductile regime machining, surface integrity. Ductile Machining of Brittle Materials. Hard and brittle materials such as glasses and ceramics are amongst the most difficult to machine.

diamond turning of brittle materials like Silicon Nitride (Si3N4) have been reported as an alternative to finishing processes such as grinding and polishing [2,3]. Ductile machining of brittle materials, where material removal is by plastic deformation is possible at very low material removal rates, usually in the micrometer range [7,8].

Abstract Ductile-regime grinding is a new technology made possible by the use of real-time control and precision engineering in the grinding process. By ensuring that the abrasive grinding forces do not exceed a threshold value, it is possible to grind materials that are normally considered "brittle" in such a way that the material removal ...

1 November 1990 Ductile regime grinding of glass and other brittle materials by the use of ultrastiff ... William J. Wills-Moren, Keith Carlisle, Patrick A. McKeown, and Paul Shore "Ductile regime grinding of glass and other brittle materials by the use of ... high stiffness CNC grinding machines for ductile mode grinding... Proceedings of SPIE ...

PREDICTIVE MODELING FOR DUCTILE MACHINING OF BRITTLE MATERIALS A Dissertation Presented to The Academic Faculty By Sivaramakrishnan Venkatachalam In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology December, 2007

Aug 07, 2013· The normal stress distribution profile associated with grinding a ductile material does not apply to grinding a brittle material like an advanced ceramic. Any induced tensile stress, which is usually caused by restricted thermal expansion at high temperatures, has already resulted in micro-cracking beneath the surface, as in a brittle material ...

[3] Z.W.Zhong in his paper on ductile or partial ductile mode machining of brittle materials discussed the machining mode for silicon, glass, and some advanced ceramics. Scanned electron ...

For the precision engineering ceramics parts, semi-ductile regime machining technologies are usually adopted to obtain the final surface. It is very important to research the brittle-ductile material removal characteristics and corresponding monitoring technology in ultrasonic aided lapping of engineering ceramics to obtain better surface quality.

Ductile-regime grinding is a new technology made possible by the use of real-time control and precision engineering in the grinding process. By ensuring that the abrasive grinding forces do not exceed a threshold value, it is possible to grind materials that are normally considered "brittle" in such a way that the material removal takes place through plastic deformation rather than fracture.

For different grinding processes, these results are also substantially improved with the change of grinding conditions. It is found that the material removal mechanism is dominated by brittle fracture at rough and semifinishing grinding processes, while ductile flow mode can be observed at the finishing grinding process.

Furthermore, an analytical and experimental investigation of the infeed rates necessary for ductile-regime grinding of brittle materials is presented. Finally, a model is proposed, relating the grinding infeed rate necessary for ductile material-removal with the properties of the brittle workpiece material.

The applied hydrostatic pressure enhanced the critical cross sectional area and reduced the cracks and chippings of all the tested materials. Effects of hydrostatic pressure on the machining characteristics of the crystalline and glassy materials are discussed in detail.

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.

With the brittle cracks remains, the finished surface quality of ultrahigh-speed machining is worse than that of high-speed machining. The results show that the material property undergoes ductile-to-brittle transition so the brittle regime machining of ductile materials …

This process is known as ductile-regime grinding. When brittle materials are ground through a process of plastic deformation, surface finishes similar to those achieved in polishing or lapping are produced. Unlike polishing or lapping, however, grinding is a deterministic process, permitting finely controlled contour accuracy and complex shapes.

Jan 01, 1997· Under appropriate conditions, brittle materials may be ground to produce surfaces with no observable fracture damage. This chapter reviews the techniques for... Ductile-Regime Grinding of Brittle Materials | NIST

grinding ductile or brittle materials. In a brittle material, the "chips" are just smaller. The removal mecha-nism for a brittle material is achieved through micro-fracture and the sub-sequent removal of the chips by the next passing grain (see Figure 1).

Precision machining of germanium and silicon was studied using single‐point diamond turning. Special attention was directed to the so‐called ductile regime wherein optical quality surface finishes can be machined directly on brittle materials.

For the ductile mode grinding of hard and brittle materials, the critical machining depth ranges from 50 nm to 1 m [20]. To perform ductile mode machining of brittle materials, machine tools with high-accuracy servomechanisms (resolution 1.25–10 nm), high loop stiffness, and full flood

the other hand, the micro-brittle fracture mechanism results in surface fracture and fragmentation. Ductile regime grinding of ceramics is preferred since no grinding flaws are introduced if the machining is performed in this mode. A theoretical model, based on fracture mechanics theory, for the determination of surface flaws has been developed ...

Brittle materials have been widely employed for industrial applications due to their excellent mechanical, optical, physical and chemical properties. But obtaining smooth and damage-free surface on brittle materials by traditional machining methods like grinding, lapping and polishing is very costly and extremely time consuming.

hard, or soft, crystalline or amorphous, etc.). Grinding of brittle materials under conditions that allow predominantly ductile material-remova l is a new technolog y known as ductile-regime grinding, which is the subject of this paper. The transition from brittle to ductile material-removal at

Ductile regime grinding, proposed by Bifano, is an important method for achieving high quality surfaces of hard brittle materials . Bifano also gave a theoretical description of the ductile grinding condition of different brittle materials, pointing out that ductile-regime grinding could be achieved by a …

2 Grinding of brittle materials Many advanced materials such as ceramics, silicon and optical glass are hard and brittle materials. Since 1980s, ductile regime grinding of brittle materials has been and is continuing to be an intensive research area because of its …

Ductile regime grinding is an effective machining process that has been used for brittle materials for several years now. In ductile regime grinding, material is removed through plastic deformation, which reduces the risk of fractures and compromised materials. Regime grinding also eliminates or minimizes the need for polishing and lapping ...

Jan 01, 2006· Effect of cutting edge truncation on ductile-regime grinding of hard and brittle materials Effect of cutting edge truncation on ductile-regime grinding of hard and brittle materials Kang, Xijun ; Tamaki, Jun'ichi ; Kubo, Akihiko 2006-01-01 00:00:00 Cutting edge truncation is a micro-truing process in which the diamond cutting edges of a grinding wheel are truncated and aligned at the same height.

In ultraprecision grinding of brittle materials, the transition from ductile-regime grinding to brittle-regime grinding that results from an increasing grinding grain depth of cut is accompanied by a reduction in the specific grinding energy. Furthermore, as the grain depth of cut is increased beyond the transition point into purely

Fig 1 Photograph of the ductile and brittle fracture on the machined shoulder. 145 x PRECISION ENGINEERING 1991 Butterworth- Heinemann 95 Blackley and Scattergood- Ductile-regime machining model for diamond turning of brittle materials Blake',' focused on measuring ductility through the movement of the ductile-to-brittle transition as a ...

Similarities and differences between ductile material and brittle material are provided in this article. At a particular temperature, a ductile material exhibits substantial plastic deformation under external loading, while a brittle material breaks with negligible plastic deformation under tensile stress.