Rotary-coordinate and shuttling-element cutting strategy for ultra-precision diamond turning of optical microstructures.

Toolpath generation techniques have become increasingly critical in ultra-precision diamond turning for optical microstructures due to the dramatically enhanced geometrical complexity of the machined region. However, the conventionally used spiral toolpath is required for interpolation from the structural models, leading to random instability of the feeding axis and additional profile error between the toolpath and designed structures, which means an enlarged effect on the machining quality in ultra-precision machining. In this paper, a rotary-coordinate and shuttling-element cutting strategy based on integrated geometrical modelling and spiral toolpath generation is presented for ultra-precision turning of optical microstructures.

E-PVT: enhanced position-velocity-time scheduler for computer-controlled optical finishing with comprehensive considerations of dynamics constraints, continuity and efficiency.

Deterministic computer-controlled optical finishing is an essential approach for achieving high-quality optical surfaces. Its determinism and convergence rely heavily on precise and smooth motion control to guide the machine tool over an optical surface to correct residual errors. One widely supported and smooth motion control model is position-velocity-time (PVT), which employs piecewise cubic polynomials to describe positions.

The mechanical, wear, antibacterial properties and biocompatibility of injectable restorative materials under wet challenge.

Objectives: To evaluate the mechanical, wear, antibacterial properties, and biocompatibility of injectable composite materials.

Methods: Two injectable composite resins (GU and BI), one flowable composite resin (FS), and one flowable compomer (DF), in A2 shade, were tested. Mechanical properties were tested via three-point bending test immediately after preparation and after 1-day, 7-day, 14-day, and 30-day water storage.

Coating-Free Superhydrophobic Hard Surfaces by Electric Discharge Machining with a Magnetic-Assisted Self-Assembly Sheet Electrode.

Artificial superhydrophobic surfaces hold significant potential in various domains, encompassing self-cleaning, droplet manipulation, microfluidics, and thermal management. Consequently, there is a burgeoning demand for cost-effective, mass-producible, and easily fabricated superhydrophobic surfaces for commercial and industrial applications. This research introduces an efficient, uncomplicated method for constructing hierarchical structures on hard substrates such as binderless tungsten carbide (WC) and glass substrates.

Surface Roughness Prediction in Ultra-Precision Milling: An Extreme Learning Machine Method with Data Fusion.

This paper pioneers the use of the extreme learning machine (ELM) approach for surface roughness prediction in ultra-precision milling, leveraging the excellent fitting ability with small datasets and the fast learning speed of the extreme learning machine method. By providing abundant machining information, the machining parameters and force signal data are fused on the feature level to further improve ELM prediction accuracy. An ultra-precision milling experiment was designed and conducted to verify our proposed data-fusion-based ELM method.

Simulation and Experimental Study of Laser Processing NdFeB Microarray Structure.

NdFeB materials are widely used in the manufacturing of micro-linear motor sliders due to their excellent permanent magnetic properties. However, there are many challenges in processing the slider with micro-structures on the surface, such as complicated steps and low efficiency. Laser processing is expected to solve these problems, but few studies have been reported.

Restraint of the mid-spatial frequency error on optical surfaces by multi-jet polishing.

Nowadays, the mid-spatial frequency (MSF) error existing in the optical surface after polishing is still a great challenge for the ultra-precision manufacturing of optical components. MSF error severely deteriorates the performances of optical components such as causing small-angle scattering and reducing imaging contrast. In this paper, multi-jet polishing (MJP) was proposed to restrain the MSF error, whose tool influence function (TIF) was relatively more complicated and adjustable than the TIFs of other tools.

Effect of the Binder during Ultra-Precision Polishing of Tungsten Carbide Using a Semirigid Bonnet Tool.

Tungsten carbide (WC) has the characteristics of high hardness, high strength, corrosion resistance, wear resistance and excellent fracture toughness. Accordingly, it has been commonly used as the material for cutting tools and molds in glass-forming techniques. To obtain ultra-smooth surfaces, fine polishing of WC is indispensable.

Curvature effect-based modeling and experimentation of the material removal in polishing optical surfaces using a flexible ball-end tool.

Optical surfaces with high quality have been widely applied in high-tech industries for their excellent performances. To precision manufacture those surfaces efficiently and effectively, various machining technologies involved become extremely crucial. As one of the promising ultra-precision machining technologies, inflated or solid elastic tool polishing has attracted more attention for its own superiority.

Multi-tool optimization for computer controlled optical surfacing.

With the rapid development of precision technologies, the demand of high-precision optical surfaces has drastically increased. These optical surfaces are mainly fabricated with computer controlled optical surfacing (CCOS). In a CCOS process, a target surface removal profile is achieved by scheduling the dwell time for a set of machine tools.

Synthesis of Green and Red-Emitting Polymethyl Methacrylate Composites Grafted from ZnAlO:Mn-Bonded GO via Surface-Initiated Atom Transfer Radical Polymerization.

A novel dual green and red-emitting photoluminescent polymer composite ZnAlO:Mn-bonded GO/polymethyl methacrylate (PMMA) was synthesized in a single-step reaction by surface-initiated atom transfer radical polymerization (SI-ATRP). The polymer chain was surface-initiated from the ZnAlO:Mn/GO, and the final products have a homogenous photoluminescent property from ZnAlO:Mn and better mechanical properties strengthened by graphene oxide (GO). The morphologies of ZnAlO:Mn/GO and the polymer composites were verified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Experimental Investigation on the Effect of Surface Shape and Orientation in Magnetic Field Assisted Mass Polishing.

Magnetic field assisted finishing (MFAF) technology has been widely used in industries such as aerospace, biomedical, and the optical field for both external and internal surface finishing due to its high conformability to complex surfaces and nanometric surface finishing. However, most of the MFAF methods only allow polishing piece-by-piece, leading to high post-processing costs and long processing times with the increasing demand for high precision products. Hence, a magnetic field-assisted mass polishing (MAMP) method was recently proposed, and an experimental investigation on the effect of surface posture is presented in this paper.

Material Removal and Surface Integrity Analysis of Ti6Al4V Alloy after Polishing by Flexible Tools with Different Rigidity.

Ti6Al4V alloy has been widely used in many fields, such as aerospace and medicine, due to its excellent biocompatibility and mechanical properties. Most high-performance components made of Ti6Al4V alloy usually need to be polished to produce their specific functional requirements. However, due to the material properties of Ti6Al4V, its polishing process still requires significant development.

Editorial for the Special Issue on "Frontiers of Ultra-Precision Machining".

Ultra-precision machining is a multi-disciplinary research area that is an important branch of manufacturing technology [...

Universal dwell time optimization for deterministic optics fabrication.

Computer-Controlled Optical Surfacing (CCOS) has been greatly developed and widely used for precision optical fabrication in the past three decades. It relies on robust dwell time solutions to determine how long the polishing tools must dwell at certain points over the surfaces to achieve the expected forms. However, as dwell time calculations are modeled as ill-posed deconvolution, it is always non-trivial to reach a reliable solution that 1) is non-negative, since CCOS systems are not capable of adding materials, 2) minimizes the residual in the clear aperture 3) minimizes the total dwell time to guarantee the stability and efficiency of CCOS processes, 4) can be flexibly adapted to different tool paths, 5) the parameter tuning of the algorithm is simple, and 6) the computational cost is reasonable.

Fabrication of Micro-Structured LED Diffusion Plate Using Efficient Micro Injection Molding and Micro-Ground Mold Core.

In this paper, a new style of micro-structured LED (light-emitting diode) diffusion plate was developed using a highly efficient and precise hybrid processing method combined with micro injection molding and micro-grinding technology to realize mass production and low-cost manufacturing of LED lamps with excellent lighting performance. Firstly, the micro-structured mold core with controllable shape accuracy and surface quality was machined by the precision trued V-tip grinding wheel. Then, the micro-structured LED diffusion plate was rapidly fabricated by the micro injection molding technology.

Time-varying tool influence function model of bonnet polishing for aspheric surfaces.

For bonnet polishing of an aspheric surface, the tool influence function (TIF) is inevitably time varying, induced by the different surface curvatures on the aspheric surface. Accordingly, this paper investigated how the surface curvature affects the bonnet-workpiece contact area, and then presented a time-varying TIF model. The time-varying TIF was modeled based on the finite element analysis and kinematics analysis methods, and validated by experiments.

Fluid jet-array parallel machining of optical microstructure array surfaces: publisher's note.

This publisher's note amends the funding section of [Opt. Express 25, 22710 (2017)].

Fluid jet-array parallel machining of optical microstructure array surfaces.

Optical microstructure array surfaces such as micro-lens array surface, micro-groove array surface etc., are being used in more and more optical products, depending on its ability to produce a unique or particular performance. The geometrical complexity of the optical microstructures array surfaces makes them difficult to be fabricated.

Unicursal random maze tool path for computer-controlled optical surfacing.

A novel unicursal random maze tool path is proposed in this paper, which can not only implement uniform coverage of the polishing surfaces, but also possesses randomness and multidirectionality. The simulation experiments along with the practical polishing experiments are conducted to make the comparison of three kinds of paths, including maze path, raster path, and Hilbert path. The experimental results validate that the maze path can warrant uniform polishing and avoid the appearance of the periodical structures in the polished surface.

Dwell-time algorithm for polishing large optics.

The calculation of the dwell time plays a crucial role in polishing precision large optics. Although some studies have taken place, it remains a challenge to develop a calculation algorithm which is absolutely stable, together with a high convergence ratio and fast solution speed even for extremely large mirrors. For this aim, we introduced a self-adaptive iterative algorithm to calculate the dwell time in this paper.