Cup wheel grinding-induced subsurface damage in optical glass BK7: An experimental, theoretical and numerical investigation

Solhtalab, Akbar; Adibi, Hamed; Esmaeilzare, Amir; Rezaei, Seyed Mehdi

doi:10.1016/j.precisioneng.2019.04.003

Cited by 39 publications

(7 citation statements)

References 41 publications

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“…They were produced from the machining with a cup grinding wheel with circular geometry. There is a limited number of published works that used diamond cup wheels for optical grinding 24 . It is understood that the nature of the streaks printed on the ground surface needs to be further investigated.…”

Section: Step 1: Grinding Of the β-Sic Plates: Feasibility Testmentioning

confidence: 99%

High-quality Finishing Process for Silicon Carbide Optical Components Using Conventional Equipment

2022

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The development of low-cost high quality surface finishing methods for silicon carbide (SiC) is an arduous task. Nowadays, the SiC mirrors manufacture involves extensive, complex, and costly finishing processes carried out on highly expensive ultra-precise machines. In this work, a cost-effective surface finishing method has been successfully developed, using conventional machines for the optical finishing of SiC. The results showed that the combination of ductile grinding and polishing in conventional low-cost machines allowed to obtain high-quality surface finish on SiC substrates with low roughness (4 -10 nm Ra ) and optical figure in the range λ / 4 -λ / 8, at a reduced 32 hours total processing time.

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Section: Step 1: Grinding Of the β-Sic Plates: Feasibility Testmentioning

confidence: 99%

High-quality Finishing Process for Silicon Carbide Optical Components Using Conventional Equipment

2022

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“…The results of the literature on grinding brittle materials show that the crack distribution characteristics are strikingly different [ 11 , 18 , 19 , 20 , 21 , 22 , 23 ]. By observing the subsurface damage of grinding BK7, Li found that the direction of the crack was random because the direction of the abrasive grits load was random [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

“…By observing the subsurface damage of grinding BK7, Li found that the direction of the crack was random because the direction of the abrasive grits load was random [ 21 ]. Solhtalab et al [ 22 ] detected the subsurface crack distribution characteristics of BK7 ground by a cup wheel. In their work, the crack distribution was random and did not have directionality (Figure 6 in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…In their work, the crack distribution was random and did not have directionality (Figure 6 in Ref. [ 22 ]). Suratwala et al [ 11 ] used magneto-rheological finishing (MRF) to polish the surface of the ground-fused silica to observe the damage depth, and they found that the distribution of cracks was random and had no obvious directionality.…”

Section: Introductionmentioning

confidence: 99%

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Distribution Characteristics of Sub-Surface Cracks in Fused Quartz Ground with Different Worn Wheels

et al. 2022

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The crack distribution characteristics in grinding damage have a significant impact on subsequent polishing efficiency and part strength. Grinding tests were carried out on fused quartz using grinding wheels with different wear states. The results showed that the cracks produced by sharp abrasive grits were mainly near chevron cracks and had no preferred direction. However, the blunt abrasive grits produced near partial cone cracks had a preferred direction. At a depth of 96.7 μm from the surface, the amount of cracks in the range of 50°~90° with an inclination angle between the crack and the cutting direction could reach 88.9%. The statistical results showed that the depth and total length of cracks produced by sharp grits were larger than those produced by blunt grits (the maximum crack depth difference was about 40 μm). Therefore, it was concluded that sharp abrasive grits were not conducive to damage control. The findings of this research enhance our understanding of the formation mechanism of grinding damage.

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“…The grinding experiments of silica glass with a coarse abrasive diamond wheel indicated that the ductile mode grinding and brittle mode grinding can be realized by changing the ratio of the workpiece feed speed to the grinding depth [5]. Solhtalab et al [6] studied the cup wheel grinding-induced subsurface damage in BK7 optical glass. Any increase in undeformed chip thickness leads to an enhancement in surface roughness and crack length.…”

Section: Introductionmentioning

confidence: 99%

Mechanism analysis and modelling of surface roughness for CeO2 slurry assisted grinding of BK7 optics considering both particle size and mass fraction

Zhang¹,

Yao

Li³

et al. 2022

Preprint

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Prolonged polishing deteriorates the shape accuracy of an optical element and reduces production efficiency simultaneously. In order to reduce the amount of polishing and polishing time, even obtain polish-free fine surfaces, a cerium oxide (CeO2) slurry assisted grinding (SAG) is investigated. A novel theoretical model was established to predict the surface roughness of the workpiece processed by CeO2 SAG. The modelling considered the effects of the protrusion height of active grains in the grinding wheel and the sizes and mass fractions of CeO2 particles in the grinding zone on undeformed chip thickness (UCT). Then, the mechanism of CeO2 SAG was investigated through nanoindentation method. Indentation hardness and energy spectrum of the surface were estimated to verify the softened layer. The results showed that the model of surface roughness was well consistent with the experiment. The CeO2 particle size significantly influenced on the surface roughness than the mass fraction. The load-bearing effect of larger CeO2 particle size reduced the protruding height of the grinding wheel grains and reduced the UCT to a greater extent in grinding process. The chemical reaction between CeO2 slurry and BK7 glass results in a softening layer which enhances the critical load and critical depth of ductile-brittle transition of grinding. Finally, the optimized parameters were used for CeO2 SAG of an ellipsoid BK7 optics.

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Cup wheel grinding-induced subsurface damage in optical glass BK7: An experimental, theoretical and numerical investigation

Cited by 39 publications

References 41 publications

High-quality Finishing Process for Silicon Carbide Optical Components Using Conventional Equipment

High-quality Finishing Process for Silicon Carbide Optical Components Using Conventional Equipment

Distribution Characteristics of Sub-Surface Cracks in Fused Quartz Ground with Different Worn Wheels

Mechanism analysis and modelling of surface roughness for CeO2 slurry assisted grinding of BK7 optics considering both particle size and mass fraction

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