Theoretical analysis on effects of grain size variation

et al. 2020

Precision Engineering

Micromachining of brittle materials like monocrystalline silicon to obtain deterministic surface topography is a 21 st Century challenge. As the scale of machining has shrunk down to sub-micrometre dimensions, the undulations in the machined topography start to overlap with the extent of elastic recovery (spring back) of the workpiece, posing challenges in the accurate estimation of the material's elastic recovery effect. The quantification of elastic recovery is rather complex in the grinding operation due to (i) randomness in the engagement of various grit sizes with the workpiece as well as (ii) the high strain rate employed during grinding as opposed to single grit scratch tests employed in the past at low strain rates. Here in this work, a method employing inclination of workpiece surface was proposed to quantify elastic recovery of silicon in ultra-fine rotational grinding. The method uniquely enables experimental extraction of the elastic recovery and tip radius of the grits actively engaged with the workpiece at the end of the ultra-fine grinding operation. The proposed experimental method paves the way to enable

Section: Experimental Setup and Methodologymentioning

confidence: 99%

Elastic recovery of monocrystalline silicon during ultra-fine rotational grinding

Ning

Yan

et al. 2020

Precision Engineering

“…4, increasing in leads to a long and thin shape of while keeps the area of unchanged. According to the principle of continuity, is shared by the number of effective cutting edges 2 • which are evenly distributed across the wheel working surface, where is the width of wheel segment, is the density of effective cutting edge (Zhou et al, 2017). Therefore, the chip cross section removed by an individual abrasive cutting edge at the wafer radial distance is given below.…”

Section: Chip Formationmentioning

confidence: 99%

“…Here, the effective cutting edge density is an important factor to determine the chip cross section and for the rest analysis. Our previous paper (Zhou et al, 2017) has theoretically studied the distribution of protrusion height of abrasives on the wheel working surface and expressed as below;…”

Section: δ • (3)mentioning

confidence: 99%

“…Liu et al investigated the effects of different abrasive shapes and dressing to predict surface roughness in grinding using kinematic simulations (Liu et al, 2013). Our previous study (Zhou et al, 2017) has theoretically analyzed the effects of grain size variation on the wafer surface topography. The study found that the actual surface roughness could become several folds larger than the theoretical prediction.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Material removal mechanism in rotary in-feed grinding - Modeling and analysis -

Shimizu

et al. 2020

JAMDSM

Self Cite

The rotary in-feed grinding is the most promising process to ensure the controllability of wafer geometry including the thickness and flatness. This makes it be widely applied into manufacturing of mono-crystal wafers, such as silicon, silicon carbide, sapphire, lithium tantalate, and etc. Unlike the conventional surface grinding, however, the rotary in-feed grinding is a complex material removal operation in which the extent of interaction between the abrasives and wafer keeps varying during the wheel/wafer contact zone. Such characteristic property significantly influences the chip formation, the homogeneousness of surface topography, the variations in grinding forces and the power consumption in the radial direction of the wafer.In this paper, the grinding mechanisms including the geometry, statics and surface topography were theoretically analyzed on a proposed grinding model and organized as follows. Described in Section 2 is the geometric analysis which mathematically expresses the wafer profile and a variety of information regarding to the dimensions of chip formed. The results suggest that the chip cross section increases proportionally as increasing in the wafer radial distance. Based on the results of chip formation, the grinding forces respectively exerted on an individual abrasive, a single wheel segment and whole wafer are calculated in the Section 3. Also, the necessary grinding power and generated grinding heat are estimated by statics analysis. In the Section 4, the surface roughness and its variation in a radial direction of the wafer are then derived by taking into consideration of the distribution of abrasive protrusion in height-wise.

“…These researches showed that the cross-sectional shape of abrasive grits has a non-negligible effect on surface roughness. Besides, there are some other parameters, such as abrasive radius [18] and the height of the cutting edge [19], also influence the ground surface roughness. These abrasive grits related parameters are sensitive to wheel wear and are unsteady during the grinding process.…”

mentioning

confidence: 99%

Wheel Wear Related Instability in Grinding of Quartz Glass

Wang

Pan

et al. 2021

Preprint

Grinding is a popular method for producing high-quality parts made of hard and brittle materials. A lot of researchers have focused on the impact of grinding parameters on surface quality. However, only a few studies discussed the surface quality instability caused by the grinding wheel wear during a long grinding process. In this paper, through wheel state monitoring and surface quality testing of ground samples, it is found that the relationship between ground surface roughness and theoretical undeformed chip thickness is significantly affected by the grinding wheel wear state, rather than maintain steady as described in most available models. By introducing the normal grinding force, a linearly relationship was found among normal grinding force, undeformed chip thickness and ground surface roughness. Besides, sensitivity analysis was conducted to guide the parameter adjustment to maintain the stability of ground surface roughness and grinding state. The mechanism of the effect of wheel wear on normal grinding force was also studied in detail. This study will help to further understand the mechanism of the influence of wheel wear on the grinding stability.