Polishing process, is an important process of ensuring surface quality and precision. However, it is difficult to achieve quantitative material removal and polish to target surface profile ...accurately, due to the special structure characteristic of polishing pad and the complex contact mechanism between polishing pad-abrasive particle-workpiece surface. Therefore, this study proposes a statistic model for polyurethane polishing pad surface, which take into consideration of the circular hole size (Gaussian distribution), density and location distribution (random distribution) on polishing pad surface. On the basis of the polishing pad surface model, this study further establishes a predicting model for polishing surface profile through analyzing of the effective number of abrasive particles between polishing pad and workpiece, the real contact force between a single abrasive particle and workpiece surface, the single abrasive particle footprint, the overlapping and superimposing of abrasive particle footprint. A series of polishing pad comparative analysis and SiC polishing experiments with different parameters are performed. Both of the two models are validated through qualitative and quantitative comparisons of simulation and experiment results. The proposed models not only lay the foundation for an in-depth understanding of the material removal mechanism in polishing process with polyurethane polishing pads, but also meaningful to other polishing process with polyurethane polishing pads and the optimization of polishing process.
With the fast development of modern science and technology, two or three-dimensional surface profile measurement techniques with high resolution and large dynamic range are urgently required. Among ...them, the techniques based on optical interferometry have been widely used for their good properties of non-contact, high resolution, large dynamic measurement range and well-defined traceability route to the definition of meter. A review focused on surface profile measurement techniques of optical interferometry is introduced in this paper with a detailed classification sorted by operating principles. Examples in each category are discussed and analyzed for better understanding.
•Optical interferometric profilometry have been used widely for good properties.•A review on profile interferometric measurement techniques is introduced with a classification.•Typical designs are selected to be examples with figures.
A mixture of sudan yellow 3G dye and poly methyl methacrylate film is fabricated by casting. The optical constants are determined using measurements of absorbance, transmittance, and reflectance ...spectra. The indirect optical band gap is obtained from Tauc's formula, which is found to be 2 eV. By excitation of the sample with a continuous wave laser beam, the nonlinear optical and the optical limiting properties are studied. The change in refractive index, Δn, and nonlinear refractive index, n2, for the sample is calculated from the diffraction ring patterns and is found to be 44.10 × 10−3 and 18.29 × 10−6 cm2/W respectively. We employ Z-scan to determine nonlinear refractive index n2 = 0.6 × 10−6 cm2/W and nonlinear absorption coefficient β = 8.79 × 10−3 cm/W. The sample is proven to possess the properties of an optical limiter, as the threshold limiting value of the film is equal to 5.3 mW.
The peel‐off strength of the electroplated specimens exhibits corresponding increase, particularly pronounced in ABS‐rich blends. However, it is observed that the interface displays incomplete ...contact between the metal and polymer. We suggest a new parameter, the Sdr ratio (Sdr,polymer/Sdr,plating), which provides the prediction of the adhesion strength of the physically interlocked metal‐polymer interface. The change in Sdr ratio effectively reflects the change of peel‐off strength, which is more efficient for phases with increasing ABS content. By examining the relationship between surface morphology and adhesion strength, our research provides the insights into optimizing the adhesion properties of electroplated metal‐polymer interfaces for PC/ABS blend.
The peel‐off strength of the electroplated specimens exhibits corresponding increase, particularly pronounced in ABS‐rich blends. However, it is observed that the interface displays incomplete contact between the metal and polymer. We suggest a new parameter, the Sdr ratio (Sdr,polymer/Sdr,plating), which provides the prediction of the adhesion strength of the physically interlocked metal‐polymer interface. The change in Sdr ratio effectively reflects the change of peel‐off strength, which is more efficient for phases with increasing ABS content. By examining the relationship between surface morphology and adhesion strength, our research provides the insights into optimizing the adhesion properties of electroplated metal‐polymer interfaces for PC/ABS blend.
A new method to quantify the ridging phenomenon in ferritic stainless steels has been developed based on the evaluation of surface profiles after the tensile elongation of 100 mm wide sheet ...specimens. The ridging components of the surface profiles are extracted by a tailored spline filtering procedure. A ridging index is proposed to quantify the severity of the surface defect based on surface profile height and spacing parameters. The procedure is independent of the type of profilometer used as long as unfiltered raw profiles can be recorded. The reproducibility of the measurement method and its correlation with the visual assessment of strained specimens is discussed.
•The surface topography of large-diameter optical elements is a key parameter that determines the overall performance index of high-precision optical systems. The precise measuring of the surface ...topographies of large optical components is essential. To address the problems associated with high-precision phase shift of heavily loaded reference mirror in large-aperture interferometry, this study introduces a method based on nano-precision grating sensor monitoring.•We proposed a mechanical phase shifting method based on heavy-load reference mirror. Nanoscale resolved spatial translation of heavy-load reference mirrors by air-bearing support gravity load and reference mirror spatial phase shift error calibration model.•We proposed a phase-shift error calibration algorithm based on nanometer-scale grating scale monitoring. In-situ monitoring of three points in space with PID closed-loop drive by combining nano-precision grating sensors with piezoelectric ceramics.•We proposed a nanometer-scale phase shifting driving method. It achieves heavy-load reference mirrors in spatial nanoscale phase shifting by spatial three-point synchronous driving of piezoelectric ceramics combined with flexible hinges.•The final realization of high-precision and high-stability mechanical phase shifting in large-aperture interferometry circumvents the principle defects of existing large-aperture wavelength-tuned phase shifting. The established heavy-load reference mirror mechanical phase shift system has a resolving power of 1.5 nm, frequency response of 116 Hz, and synchronization accuracy of 2° for the three-phase shift quantities.•This method provides a new phase shifting technique for the construction of large-aperture phase-shifting interferometers and provides an effective way to improve the accuracy of large-diameter optical inspection and processing.
In large-aperture interferometry, achieving high-precision phase shifting for heavy-load reference mirrors is challenging. This study introduces a method based on nano-precision grating sensor monitoring. The technique utilizes spatial three-point synchronous driving by piezoelectric ceramics, combined with flexible hinges, to enable nanoscale phase shifting of heavy-load reference mirrors. Additionally, it integrates in-situ PID closed-loop drive monitoring at these three points, using nano-precision grating sensors and piezoelectric ceramics. To ensure nanoscale resolved spatial translation, the mirrors are supported by air-bearings that counteract gravity, coupled with a phase shift error calibration model. The final realization of high-precision and high-stability mechanical phase shifting in large-aperture interferometry circumvents the principle defects of existing large-aperture wavelength-tuned phase shifting. The experiments show that the established mechanical phase shifting system with heavy-load reference mirror has a resolution of 1.5 nm, a frequency response of 116 Hz, and a synchronization accuracy of 2° for the three phase shifting quantities, and the method provides a new method and means of phase shifting for the construction of large-aperture phase shifting interferometer.
Poor surface quality of Additively Manufactured (AM) components, can greatly increase the overall cost and lead time of high-performance components. Examples are medical devices where surfaces may ...contact the patient's skin and hence need to be smooth and aerospace components with high fatigue strength requirements where surface roughness could reduce fatigue life. The average surface roughness (Ra) of AM parts can reach high levels greater than 50 μm and maximum distance between the high peaks and the low valleys of more than 300 μm. As such, there is a need for fast, cost effective and selective finishing methods of AM produced components targeted at high-performance industries. In this paper Ti-6Al-4V Grade 23 ELI, popular for medical devices and aerospace parts production, was L-PBF processed to manufacture parts which were subsequently treated via laser polishing. Here in this work, CO2 laser polishing was used for the surface modification of the Ti-6Al-4V produced samples. The most significant processing parameters were optimised to achieve approximately an 80% reduction in the average surface roughness and a 90% reduction in the peak-to-valley distance with a processing time of 0.1 s/mm2 and cost of 0.2 €/cm2.
•CO2 laser polishing of additively manufactured Ti-6Al-4V is presented.•Flat and cylindrical samples were successfully polished by using the methodology detailed in this article.•The percent overlap of the laser scanning track was an effective processing parameter to reduce surface roughness.•Double-pass lasing offered a further reduced surface roughness.
Fractal dimension is the most important parameter for surface characterization. In this paper, four methods used to estimate the fractal dimensions of surface profiles and their applications in ...machined surfaces are studied. These methods are first evaluated using surface profiles created by Weierstrass–Mandelbrot function from the three aspects of fitting accuracy, calculation accuracy and calculation stability, and then applied to the machined rough surfaces. By comparing the results of the four methods, it is found that none of the methods is particularly prominent in all of the three aspects. However, the three point sinuosity method is found to be relatively the most suitable and reliable method among the four tested methods for extracting fractal dimensions of both generated and measured rough surface profiles.
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