Generative Precision Grinding of Optical Glass

Sinhoff, V.; König, Wilfried

doi:10.1016/s0007-8506(07)62829-7

Cited by 12 publications

(5 citation statements)

References 11 publications

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“…The self-defined constitutive model is employed to characterize the behavior of the material, thereby encompassing the determination of the mold properties. The material’s yield and failure criteria are established using the Drucker–Prager criterion that considers various factors such as hydrostatic pressure, work hardening, strain rate, and thermal softening [ 15 ]. This criterion is expressed as:

where

is the working hardening function,

is the strain rate function, and

is the thermal softening function.…”

Section: Resultsmentioning

confidence: 99%

A Study on the Material Removal Characteristics and Damage Mechanism of Lapping for Pressureless Sintered Silicon Carbide (SSiC) Microlens Cavity

Zhou,

Li,

Guo

et al. 2023

Micromachines

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Microlens arrays have been widely employed to control the reflection, refraction, and diffraction characteristics of light due to its distinctive surface properties. Precision glass molding (PGM) is the primary method for the mass production of microlens arrays, of which pressureless sintered silicon carbide (SSiC) is a typical mold material due to its excellent wear resistance, high thermal conductivity, high-temperature resistance, and low thermal expansion. However, the high hardness of SSiC makes it hard to be machined, especially for optical mold material that requires good surface quality. The lapping efficiency of SSiC molds is quite low. and the underlying mechanism remains insufficiently explored. In this study, an experimental study has been performed on SSiC. A spherical lapping tool and diamond abrasive slurry have been utilized and various parameters have been carried out to achieve fast material removal. The material removal characteristics and damage mechanism have been illustrated in detail. The findings reveal that the material removal mechanism involves a combination of ploughing, shearing, micro-cutting, and micro-fracturing, which aligns well with the results obtained from finite element method (FEM) simulations. This study serves as preliminary reference for the optimization of the precision machining of SSiC PGM molds with high efficiency and good surface quality.

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where

is the working hardening function,

is the strain rate function, and

is the thermal softening function.…”

Section: Resultsmentioning

confidence: 99%

A Study on the Material Removal Characteristics and Damage Mechanism of Lapping for Pressureless Sintered Silicon Carbide (SSiC) Microlens Cavity

Zhou,

Li,

Guo

et al. 2023

Micromachines

View full text Add to dashboard Cite

show abstract

“…They concluded that material pulverization was the dominant material removal mechanism in BK7 grinding as long as the depth of cut was bigger than a critical value. Sinhoff and König [8] tried to establish a theoretical model that can describe BK7 behaviors in the grinding process. This model considered BK7 damage as the result of both the brittle fracture and the transition from brittle fracture to ductile plow removal.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on grinding characteristics of optical glass BK7: with special emphasis on the effects of machining parameters

Wang

2015

Int J Adv Manuf Technol

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As a kind of widely used optical material, optical glass BK7 is machined by first grinding and then polishing in industrial production. However, the polishing process is timeconsuming and high-cost. Therefore, it is very meaningful to produce high-quality BK7 workpieces by grinding. To understand the grinding characteristics of BK7, many studies were conducted and reported. But most studies available so far had low industrial relevance and were difficult to be applied to guide real production of BK7 glass. To fill this gap, in this study, BK7 grinding characteristics are investigated and special emphasis is laid on the effects of machining parameters in terms of machined surface morphology, subsurface damage, and grinding force. Results show that wheel depth of cut plays the most important role in BK7 grinding, and a little difference of it leads to completely different material removal modes. Wheel speed is the second important parameter. It cannot change the dominant removal mode but can slightly adjust the characteristics of machined surface, subsurface damage, and grinding force. Workpiece feed rate has a small impact on BK7 grinding. From the viewpoint of industrial application, it suggests that the wheel depth of cut of 1.0 μm, high wheel speed, and high workpiece feed rate are more rational and practical because under this condition the grinding process can produce BK7 workpieces, which possess crack-free surface and sublet subsurface damage, with high removal rates and stable grinding forces. The findings of this paper are expected to be meaningful to provide the experimental references for the studies of the BK7 grinding process and guide industrial production of BK7 optical components.

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“…Hence, it would be a better idea to produce these glass micro-features by mechanical processes [2]. Literature review shows that many researchers have studied glass machining process which involves single-point diamond turning tool [3,4], conventional grinding wheel [5][6][7][8][9][10][11][12], and milling cutter [13][14][15]. However, the hardness and brittleness of glass makes these mechanically micro-machining processes problematic due to damage resulting to brittle fracture, cutting forceinduced tool deflection or breakage, and tool wear [16].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of different geometry cutting tools and their effect on the vertical micro-grinding of BK7 glass

Perveen

San

Rahman

2011

Int J Adv Manuf Technol

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With the demand for microstructures of not only with diversified shape but also of reduced dimension on glass, fabrication of polycrystalline diamond (PCD) tool/ microelectrodes with different shape has become important. However, to date, fabrication of different shapes in single setup is not possible and also needs special indexing attachment. To solve this problem, in this study, a specially designed block containing three v-slots of 60°, 90°, and 120°has been designed and fabricated using wire cut. Thereafter with the help of block electro-discharge machining method and using this specially designed block, different shapes of microelectrodes with symmetrical and non-symmetrical section has been fabricated. This study also investigates the feasibility of using these different geometry PCD tool for micro-grinding of BK7 glass. In this context, a relative study on the micro-grinding performance of four different geometry tools (circular, D-shaped, triangular, and square) has been carried out. It has been observed that among the different shaped tools, D-shaped tool experienced lowest cutting force along x-and y-axes where as triangular tool faced lowest force along z-axis, and highest cutting forces were found to be experienced by square tool. Average and maximum roughness of machined surface was found to be improved from circular to others tool except triangular one. But, it was also observed that side surface started to deteriorate from circular to other tool due to edge wear. In case of tool wear, square and triangular tool experienced more wear than circular and D-shaped tool due to their frequent edge blunting or rounding effect. Finally, among four different geometry tools, D-shaped tool was considered to provide better performance in terms of the achieved surface finish, tool wear, and cutting force analysis.

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Generative Precision Grinding of Optical Glass

Cited by 12 publications

References 11 publications

A Study on the Material Removal Characteristics and Damage Mechanism of Lapping for Pressureless Sintered Silicon Carbide (SSiC) Microlens Cavity

A Study on the Material Removal Characteristics and Damage Mechanism of Lapping for Pressureless Sintered Silicon Carbide (SSiC) Microlens Cavity

Experimental investigation on grinding characteristics of optical glass BK7: with special emphasis on the effects of machining parameters

Fabrication of different geometry cutting tools and their effect on the vertical micro-grinding of BK7 glass

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