Grinding Wheel Elasticity

1971 ◽  
Vol 93 (2) ◽  
pp. 609-613 ◽  
Author(s):  
K. Nakayama ◽  
J. Brecker ◽  
M. C. Shaw
Keyword(s):  
Contact Zone ◽  
Chip Thickness ◽  
Grinding Wheel ◽  
Undeformed Chip Thickness ◽  
Fine Grinding ◽  
Abrasive Grains ◽  
Work Material ◽  
Cutting Surface ◽  
Order Of Magnitude ◽  
Zone Deformation

The deflection of individual abrasive grains in the cutting surface of a vitrified grinding wheel has been postulated to explain many fine grinding results; however, the magnitude of the deflection has never been firmly established. Experiments conducted to measure the deflection associated with an individual grain showed it to be of the same order of magnitude as the undeformed chip thickness. A model of a grinding wheel which allows both the deflection of the center of an individual grain and the deformation in the contact zone between the grain and the work material to be evaluated was developed. Contact zone deformation was found to be approximately twice as great as the deflection of the center of the grain.

The Role of Grain Tip Radius in Fine Grinding

1975 ◽  
Vol 97 (3) ◽  
pp. 1119-1125 ◽  
Author(s):  
G. K. Lal ◽  
M. C. Shaw
Keyword(s):  
Grain Size ◽  
Surface Finish ◽  
Chip Thickness ◽  
Radius Of Curvature ◽  
Undeformed Chip Thickness ◽  
Fine Grinding ◽  
Abrasive Grains ◽  
Grinding Conditions ◽  
Tip Radius

The scratches produced by single abrasive grains in overcut fly milling show that the transverse shape of a grain is closely approximated by an arc of a circle. This radius of curvature is found to be independent of grain type and grinding conditions but varies with the grain size. The equation for undeformed chip thickness for surface grinding is rederived in terms of this radius. The important role that the transverse curvature of the grain plays relative to surface finish is also discussed.

Geometrical Contact Zone Analysis of the Skive Hobbing Process

2016 ◽  
Vol 1140 ◽  
pp. 157-164
Author(s):  
Volker Böß ◽  
Berend Denkena ◽  
Marc André Dittrich ◽  
Stefan Henning
Keyword(s):  
Contact Zone ◽  
Material Removal ◽  
Chip Thickness ◽  
Analytical Description ◽  
Process Modelling ◽  
Innovative Approach ◽  
Orthogonal Direction ◽  
Cartesian Coordinates ◽  
Undeformed Chip Thickness

In this paper, an innovative approach for contact zone analysis of skive hobbing is presented. This process is characterised by varying tool engagements and very small chip thicknesses. The paper describes the process-modelling and the analysis of the workpiece-tool contact. For efficient modelling, a novel dexel-based method for the description of a gear segment with discretized stock allowance is presented. Characteristic for the method is an analytical description of the target workpiece contour which allows to describe points of the surface by Cartesian coordinates on the winding off. On this workpiece contour, dexel are modelled in surface-orthogonal direction. The initial lengths of these dexel describe the stock allowance. By cutting these dexel with a tool, a time-and position-dependent prediction of material removal values, like width of undeformed chip, undeformed chip thickness or cutting directions can be obtained. Selected results are presented and interpreted.

Analysis on the Effects of Grinding Wheel Speed on Removal Behavior of Brittle Optical Materials

2016 ◽  
Author(s):  
Ping Li ◽  
Tan Jin ◽  
Zongfu Guo ◽  
Jun Yi ◽  
Meina Qu
Keyword(s):  
Surface Quality ◽  
Material Removal ◽  
Optical Materials ◽  
Chip Thickness ◽  
Ground Surface ◽  
Subsurface Damage ◽  
Wheel Speed ◽  
Grinding Wheel ◽  
Undeformed Chip Thickness ◽  
Grinding Processes

It is often desired to increase the machining rate while maintaining the desired surface and subsurface integrity during fabricating high-quality optical glass components. This paper proposed a high-speed high-efficiency low-damage grinding technology for machining brittle optical materials, which consists of three grinding processes: rough grinding, semi-finishing grinding and finishing grinding. Grinding characteristics is investigated with respect to grinding forces, specific cutting energy, surface roughness, ground surface quality, subsurface damage, and material removal mechanisms in grinding of fused silica optical glasses with this technology at the grinding speeds of up to 150 m/s. These indications are thoroughly discussed by contacting the undeformed chip thickness. The results indicate that the level of these indications are significantly improved with an increase in the wheel speed due to the decrease of the undeformed chip thickness. It is also found that the improvement of ground surface quality is limited when the wheel speed from 120 m/s increases to 150 m/s may be due to the influence of vibration caused by the higher wheel speed. 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 semi-finishing grinding processes, while ductile flow mode can be observed at the finishing grinding process. There are some differences between the experimental results and the previous predicted model of subsurface damage depth.

Regular Surface Texture Generated by Special Grinding Process

2009 ◽  
Vol 131 (1) ◽  
Author(s):  
Piotr Stȩpień
Keyword(s):  
Surface Texture ◽  
Chip Thickness ◽  
Active Surface ◽  
Wheel Speed ◽  
Random Component ◽  
Regular Surface ◽  
Abrasive Grains ◽  
Work Material ◽  
Texture Generation ◽  
Nominal Surface

Most of the methods for generating regular surface texture (RST) consist of shaping a set of regular grooves (cavities) arranged in a regular way. This paper presents possibilities for regular surface texture generation by so-called “pattern grinding” with the wheel prepared in a special way. The simple variant of the method involves grinding with the wheel having helical grooves. The grooves shaped on the work material are the result of specific wheel surface reproduction. The ratio between work-material feed and wheel speed is an important factor, determining the layout of the grooves generated on the work-material and the shape of the groove sides. Surface texture consists of two components: deterministic, resulting from the nominal wheel active surface, and random, resulting from the random shape and arrangement of abrasive grains. The limited contribution of the random component of surface texture is discussed based on the ratio between the undeformed chip thickness and the sizes of the grooves. Kinematical analysis of the wheel reproduction process is performed for description of nominal surface texture. Experimental results of flat and cylindrical surfaces, obtained with pattern grinding are also provided. Two critical values of the ratio between work-material feed and wheel speed were derived, and three ranges of this ratio are discussed. The kinematical approach provided relationships between input data of the process (wheel shape and grinding parameters) and nominal groove dimensions and groove layout. The geometrical characteristics of the work-material nominal surface texture are presented for each of the three types of surface texture. It is important to ensure that the work feeds are greater than the lower critical value. For achievable work feeds the shape of the sides of the grooves is cycloid. Experiments revealed the limited contribution of the random component of the surface structure of the work material. Random arrangement of abrasive grains is important only at local (micro-) level and affects the roughness of groove bottoms, while the dimensions and arrangement of the grooves are affected only to a minimal degree.

Analysis on the Effects of Grinding Wheel Speed on Removal Behavior of Brittle Optical Materials

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Ping Li ◽  
Tan Jin ◽  
Zongfu Guo ◽  
Jun Yi ◽  
Meina Qu
Keyword(s):  
Surface Quality ◽  
Material Removal ◽  
Optical Materials ◽  
Chip Thickness ◽  
Ground Surface ◽  
Subsurface Damage ◽  
Wheel Speed ◽  
Grinding Wheel ◽  
Undeformed Chip Thickness ◽  
Grinding Processes

It is often desired to increase the machining rate while maintaining the desired surface and subsurface integrity during fabricating high-quality optical glass components. This paper proposed a high-speed high-efficiency low-damage grinding technology for machining brittle optical materials, which consists of three grinding processes: rough grinding, semifinishing grinding, and finishing grinding. Grinding characteristics are investigated with respect to grinding forces, specific cutting energy, surface roughness, ground surface quality, subsurface damage, and material removal mechanisms in grinding of fused silica optical glasses with this technology at grinding speeds of up to 150 m/s. These indications are thoroughly discussed by contacting the undeformed chip thickness. The results indicate that the level of these indications is significantly improved with an increase in the wheel speed due to the decrease of the undeformed chip thickness. It is also found that the improvement of ground surface quality is limited when the wheel speed increases from 120 m/s to 150 m/s, which may be due to the influence of vibration caused by the higher wheel speed. 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. There are some differences between the experimental results and the previous predicted model of subsurface damage depth.

Surface Grinding Force Model of Steel 55 Based on Undeformed Chip Thickness with CBN Electroplated Wheels

2011 ◽  
Vol 189-193 ◽  
pp. 1768-1773 ◽  
Author(s):  
Jun Ming Wang ◽  
Ren Zhen Ye ◽  
Hui Peng Chen ◽  
Hong Zan Bin
Keyword(s):  
Velocity Ratio ◽  
Influence Factors ◽  
Chip Thickness ◽  
Grinding Force ◽  
Calculation Model ◽  
Surface Grinding ◽  
Force Model ◽  
Undeformed Chip Thickness ◽  
Abrasive Grains ◽  
Random Direction

Undeformed chip thickness is one of the most important parameters in grinding process, which is related to the entire abrasive grains in grinding simultaneously and changed periodically with time. Simplifying the geometric shape of abrasive grains ,the paper modifies the mathematic models of undeformed chip thickness by analytic method, establishes an universal calculation model of grinding force based on undeformed chip thickness, then optimizes the parameters of the model by restrictive random direction method according to the measuring experiments of the inter-grain spacing about CBN electroplated wheels and the grinding experiments of steel 55 during surface grinding, analyses the influence factors of the friction ratio on the grinding force. The results show that under the same grinding depth， both of the ratio and the grinding force will be decreased with the increase of velocity ratio VS/VW, but the ratio increases and the grinding force decreases with the increase of inter-grain spacing.

scholarly journals Wheel Wear Related Instability in Grinding of Quartz Glass

2021 ◽  
Author(s):  
Yonghao Wang ◽  
Ping Zhou ◽  
Yuhang Pan ◽  
Ying Yan ◽  
Dongming Guo
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Chip Thickness ◽  
Ground Surface ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Wheel Wear ◽  
Undeformed Chip Thickness ◽  
Grinding Wheel Wear ◽  
Ground Surface Roughness

Abstract 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.

scholarly journals Geometric Analysis of Undeformed Chip Thickness in Ball-Nosed End Milling

2004 ◽  
Vol 47 (1) ◽  
pp. 2-7 ◽  
Author(s):  
Hisanobu TERAI ◽  
Minghui HAO ◽  
Koichi KIKKAWA ◽  
Yoshio MIZUGAKI
Keyword(s):  
End Milling ◽  
Geometric Analysis ◽  
Chip Thickness ◽  
Undeformed Chip Thickness
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