New Freeform Manufacturing Chains based on atmospheric Plasma Jet Machining

Arnold, Thomas; Boehm, Gerhard; Paetzelt, Hendrik

doi:10.2971/jeos.2016.16002

Cited by 20 publications

(10 citation statements)

References 6 publications

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“…This is due to the fact that the relative motion of the plasma jet leads to the convolution of the local removal function

R (x, y)

with the plasma dwell time

t

at certain coordinates

x, y

in the Cartesian coordinate system. Then, the local etching depth

D (x, y)

is determined as follows:

D (x, y) = \iint R (x - \overset{x}{true}, y - \overset{y}{true}) \cdot t (\overset{x}{true}, \overset{y}{true}) d \bar{x} d \bar{y}

…”

Section: Resultsmentioning

confidence: 99%

“…In this context, a local dry etching process based on reactive plasmas and plasma jets was proposed as one step of a process chain for surface form generation and residual topography error correction as an alternative to freeform grinding and subaperture‐polishing . Such a process chain comprising plasma machining and soft tool polishing has been successfully applied for freeform fabrication of fused silica optical elements . It has been shown, that reactive plasma jet machining (PJM) provides high flexibility regarding the aimed shape, high process convergence, and avoidance of subsurface damage (SSD) due to the chemical nature of material removal.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Development of a model for ultra‐precise surface machining of N‐BK7® using microwave‐driven reactive plasma jet machining

Kazemi

Boehm

Arnold

2019

Plasma Processes & Polymers

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In this paper, extensive studies are conducted as key to overcoming several challenging limitations in applying fluorine‐based reactive plasma jet machining (PJM) to surface machining of N‐BK7®, particularly regarding the manufacture of freeform optical elements. The chemical composition and lateral distributions of the residual layer are evaluated by X‐ray photoelectron spectroscopy and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy analysis aiming at clarifying the exact chemical kinetics between plasma generated active particles and the N‐BK7 surface atoms. Subsequently, a model is developed by performing static etchings to consider the time‐varying nonlinearity of the material removal rate and estimate the local etching rate function. Finally, the derived model is extended into the dynamic machining process, and the outcomes are compared with the experimental results.

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“…This is due to the fact that the relative motion of the plasma jet leads to the convolution of the local removal function

R (x, y)

with the plasma dwell time

t

at certain coordinates

x, y

in the Cartesian coordinate system. Then, the local etching depth

D (x, y)

is determined as follows:

D (x, y) = \iint R (x - \overset{x}{true}, y - \overset{y}{true}) \cdot t (\overset{x}{true}, \overset{y}{true}) d \bar{x} d \bar{y}

…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Development of a model for ultra‐precise surface machining of N‐BK7® using microwave‐driven reactive plasma jet machining

Kazemi

Boehm

Arnold

2019

Plasma Processes & Polymers

View full text Add to dashboard Cite

show abstract

“…[ 11 ] Determined and localized dry etching enables PJM to create freeform shapes on the optical surface almost defect‐free and without any subsurface damage. [ 12 ]…”

Section: Introductionmentioning

confidence: 99%

“…[ 14–16 ] Manufacturability and fabrication efficiency are often a limiting factor when specialized individual optical elements or low lot sizes are to be produced by mechanical abrasive techniques such as grinding and subaperture polishing. [ 17 ] Here, a processing chain [ 12 ] including PJM steps comes into play, as it has been shown to be able to efficiently fabricate precise freeform surfaces. [ 10,11 ]…”

Section: Introductionmentioning

confidence: 99%

A novel Deal–Grove‐inspired model for fluorine‐based plasma jet etching of borosilicate crown optical glass

Kazemi

Boehm

Arnold

2020

Plasma Processes & Polymers

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The Deal–Grove model is a state‐of‐the‐art approach proposed for describing the thermal oxidation of silicon and the oxide thickness over time. In this study, the Deal–Grove concept provided the inspiration for a mathematical model for simulating plasma jet‐based dry etching process of borosilicate crown glass (N‐BK7®). The whole process is contained in two so‐called Deal–Grove parameters, which are extracted from experimental data including local etching depth and surface temperature distribution. The proposed model is extended for the evolution of dynamic etch profiles, and the obtained results are validated experimentally. By establishing such a model, it is possible to predict the effect of the residual layer and surface temperature on the evolution of local etching depths over dwell time.

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“…Mori et al combined elastic emission machining (EEM) and CVM for fabricating coherent X-ray optics, in which roughness in the spatial-wavelength range <1 µm was removed rapidly by EEM [24,25]. Based on the thermal effect of the plasma jet, Arnold et al developed plasma jet polishing (PJP) to improve surface quality before PJM [26]. Su et al combined APPP and BP for fabricating freeform surfaces [27,28].…”

Section: Introductionmentioning

confidence: 99%

Surface Texture Evolution of Fused Silica in a Combined Process of Atmospheric Pressure Plasma Processing and Bonnet Polishing

et al. 2019

Coatings

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The increasing demand for precision optical components invokes the requirement of advanced fabrication techniques with high efficiency. Atmospheric pressure plasma processing (APPP), based on chemical etching, has a high material removal rate and a Gaussian-shaped influence function, which is suitable to generate complex structures and correct form errors. Because of the pure chemical etching, an optically smooth surface cannot be achieved using only APPP. Thus, bonnet polishing (BP) with a flexible membrane tool, also delivering a Gaussian influence-function, is introduced to smooth the surface after APPP. In this paper, the surface texture evolution in the combined process of APPP and BP is studied. The etched texture with increased removal depth of APPP is presented and analyzed. Subsequently, the processed substrates are smoothed by BP. The texture smoothing and the roughness improvement is investigated in detail. The experimental results show that the APPP etched pits coalesce with each other and transform into irregular convex-concave structures, with roughness degraded to about 25 nm arithmetical mean deviation (Ra). The APPP etched texture can be successfully smoothed to 1.5 nm Ra, with 0.2–1 μm material removal of BP.

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New Freeform Manufacturing Chains based on atmospheric Plasma Jet Machining

Cited by 20 publications

References 6 publications

Development of a model for ultra‐precise surface machining of N‐BK7® using microwave‐driven reactive plasma jet machining

Development of a model for ultra‐precise surface machining of N‐BK7® using microwave‐driven reactive plasma jet machining

A novel Deal–Grove‐inspired model for fluorine‐based plasma jet etching of borosilicate crown optical glass

Surface Texture Evolution of Fused Silica in a Combined Process of Atmospheric Pressure Plasma Processing and Bonnet Polishing

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