Evgueni Bordatchev

The University of Western Ontario | UWO · Department of Mechanical and Materials Engineering

The natural surfaces of many plants and animals provide examples of textures and structures that remain clean despite the presence of environmental fouling contaminants. A biomimetic approach to deciphering the mechanisms used by nature will facilitate the development and application of fouling-resistant surfaces to a range of engineering challenge...

Several species of plants and animals demonstrate an ability to resist the accumulation of contaminants natural to their environments. To explain this phenomenon, mechanisms that facilitate fouling resistance have to be deciphered. Along these lines, this study is focused on the correlation between drag reduction and fouling resistance for underwat...

Laser polishing (LP) is an advanced finishing technology used to improve surface quality through laser remelting of the surface topography. A thorough understanding of the surface topography formation during laser remelting is critically required to monitor, optimize, and control the LP process. For this purpose, a method for automated detection of...

Surface polishing by laser remelting (SP-LRM) is a novel surface finishing technology that is characterized by rapidity, versatility, repeatability as well as the lack of material removal. SP-LRM can be implemented in several thermodynamic regimes whose presence depends on a complex combination of power-speed-focus-trajectory-material parameters. T...

Surface polishing by laser remelting (SP-LRM) uses the energy of a focused laser beam to remelt the thin top layer of the workpiece material in order to improve its surface quality by 3D topography smoothing. Visual observations of the experimentally-obtained remelted laser tracks revealed that the uniformity of the LRM surface topography highly de...

The increase in convenience and value of many industrial and household products due to their size and weight reduction over the years has triggered the rapid development of micromachining technologies. V-grooves have gained attention in micromachining due to their versatile use on a wide variety of products. To date, a double-flank axial cutting st...

Convolutional neural network (CNN) enhances laser polishing (LP) by reducing the complexity of thermophysical process identification through post-LP topography modelling. Furthermore, the laborious process of achieving the desired surface roughness through heuristic searches is avoided by means of AI-enhanced predictions targeting LP process parame...

Surface quality improvement by a laser polishing (LP) process is a new innovative technology enabling value-adding functionalities, such as improving visual appearance, wettability, friction, and others through the control and reconfiguration of the surface topography. However, the resultant surface is dependent upon many process parameters which m...

This work was focused on the recognition and classification of two coexisting laser remelting regimes – shallow- and deep-melting – by means of comparisons involving geometric properties extracted from metallographic cross-sections, statistical characteristics of initial and remelted surface topographies, and averaged roughness profiles. The attain...

Laser polishing is a surface finishing operation in which a superficial layer of material is being redistributed in a controlled manner, typically to achieve a better surface quality. In this study, three-dimensional numerical model has been developed to investigate the formation of remelted line during the laser polishing (LP) of H13 tool steel. T...

Light guiding is an essential functionality of automotive lighting responsible for styling, safety, and artistic effects. The functional performance of optical lighting and illumination products and components depends on novel optical designs and advanced technologies for cost-effective fabrication of tooling with strict surface quality and form ge...

One of the versatile microstructures with numerous applications is represented by V-grooves. Their range of the applicability is broad and covers many types of components from mechanical to optical. Their fabrication process is accompanied by challenges related to their tight form accuracy, shape complexity and surface quality requirements. The vas...

Surface finish is one of the most important quality characteristics of fabricated components. To complement that, laser polishing (LP) is one of the advanced manufacturing surface finishing techniques that has been recently developed and successfully employed for improving surface quality without deteriorating the overall structural form through su...

Elliptical vibration cutting (EVC) is an advanced micromachining technology that has a wide range of applications in high-precision micro/nano manufacturing. This technology is primarily used in fabrication of micro/nano-scale functional surfaces, geometrical features, optical and holographic components that are cut in ferrous and difficult-to-cut...

A method for visualization and monitoring of the laser polishing was developed using high-speed thermographic imaging. The preliminary analysis demonstrates correlation with different LP parameters suitability to process deep learning, optimization and control.

Laser polishing (LP) is an advanced manufacturing process for improving surface quality via laser remelting of the surface topography of the material. In this preliminary study, a high-speed thermographic imager was coaxially installed on a LP system and was used to capture the thermo-dynamics of the laser-material interactions under various proces...

Stability of the laser remelting (LRM) process was preliminary studied demonstrating an ability of the high-speed thermographic imaging to monitor the process conditions and estimate variations in the LRM line width.

Laser remelting (LRM) is a complex thermodynamic process that typically yields two main types of surface modifications: smoothing and bulging. These two changes are applicable to polishing and structuring, respectively. This study includes a preliminary analysis on the formation of shape and surface quality of LMR lines obtained with a defocused la...

Present report introduces some of most valuable achievements and developments of laser surface polishing and laser surface functionalization F technologies at the National Research Council of Canada over the past five years.

Surface structuring by laser processing is a key technology enabler for a wide range of surface functionalization applications. Statistical recognition of linear geometrical features produced on initially rough surfaces is developed and applied demonstrating reliable analysis of microstructures.

The main objective of this study was to demonstrate applicability of the Surface Structuring by Laser Remelting (SSLRM) process for efficient fabrication of edge-lit lightguide tools (LGT) for automotive lighting applications. Several LGTIs were fabricated demonstrating high accuracy and precision in form geometry achieving sine-shape period and am...

Light guiding is an essential functionality of automotive lighting responsible for styling, safety and artistic effects. The proposed light guide is characterized by a wedged design with a sine-shaped light-redirecting surface. In this study, a new microfabrication method called laser structuring-by-remelting was used to fabricate tooling for wedge...

Introduction. Two factors of metal turning are compared: the dissipated temperature and the power of irreversible transformations in the material of the product and the tool. The paper is devoted to the issues of mathematical modeling of their link.Materials and Methods. The mathematical apparatus is based on the modification of the Volterra equati...

Surface finish is one of the most important quality characteristics of fabricated components. Laser polishing (LP) is one of the advanced manufacturing surface finishing techniques that has been recently developed and successfully employed for improving surface quality without deteriorating the overall structural form through surface smoothing by m...

V-groove microstructures have found numerous applications in mechanical, electronic, photonic, bio-mechanical and optical components. However, despite their relatively wide use, the manufacturing strategies associated with the fabrication of V-grooves were little investigated so far. To address this, the current study provides an analytical formula...

V-groove microstructures have found a variety of applications across different fields. Presently, they are widely utilized for different surface functionalization purposes ranging from optical to non-optical. So far, single point cutting constitutes the main technology used to fabricate this particular type of surface microstructures. However, the...

Laser polishing (LP) represents one of the finishing/superfinishing technologies that has experienced a rapid growth over the past two decades. However, while undeniable progress has been achieved on the experimental and/or practical side, the development of the theoretical/numerical models of the continue to be somewhat slower and still dominated...

Due to their inherent functionality, retroreflective structures play a vital role in styling and safety that are typically associated with automotive lighting components. The optical performance of the automotive retroreflectors is strongly dependent on the quality of the functional facets that are involved in redirecting the incoming light. To dat...

The study of laser textured surfaces has been carried out in the pursuit of superhydrophobic and superhydrophilic functional surfaces on stainless steel and silicon carbide substrate materials, respectively. The theoretical aspects of laser texturing a surface were investigated in order to understand how replication of micro- and nanoscale features...

The study of laser textured surfaces has been carried out in the pursuit of superhydrophobic and superhydrophilic functional surfaces on stainless steel and silicon carbide substrate materials respectively. The theoretical aspects of laser texturing a surface were investigated in order to understand how replication of micro and nanoscale features c...

Flexible optical sheets are thin large-area polymer light guide structures that can be used to create innovative passive light-harvesting and illumination systems. The optically transparent micro-patterned polymer sheet is designed to be draped over arbitrary surfaces or hung like a curtain. The light guidance sheet is fabricated by bonding two or...

Ultraprecise single point inverted cutting (USPIC) is a microfabrication technique that has been recently developed for the generation of micro-optical microstructures with sharp concave geometries. Among the multiple challenges encountered during the micromachining process, tool alignment represents one of the critical factors affecting the overal...

Laser polishing is a manufacturing process in which a small amount of material is melted via laser irradiation and molten pool is then redistributed to create a smoother surface finish/superior surface quality. The focus of this study is to generate more comprehensive understanding of the effects that laser and scanner control parameters have on th...

A three-dimensional CFD model has been developed to predict track width during laser polishing (LP) of H13 tool steel. The developed model incorporates several different mechanisms for heat transfer such as conduction, convection, and radiation as well as temperature dependencies for relevant material properties. Experimental calibration was carrie...

To meet the demands of an increasingly competitive market, automakers are continuously looking for aesthetically appealing and performant lighting components. Among them, retroreflectors constitute the core functional structure of the taillights equipping virtually every vehicle available on the market. For many decades, automotive retroreflectors...

Retroreflectors (RR) are passive optical structures that are capable of returning incident light back to the source. The focus of the current study is represented by the right triangular prism (RTP) geometry which could be a more efficient alternative to the traditional inverted corner cube geometry. While current manufacturing practices rely solel...

Large area polydimethylsiloxane (PDMS) flexible optical light guide sheets can be used to create a variety of passive light harvesting and illumination systems for wearable technology, advanced indoor lighting, non-planar solar light collectors, customized signature lighting, and enhanced safety illumination for motorized vehicles. These thin optic...

Imaging applications at terahertz frequencies are, in general, limited to relatively low spatial resolution due to the effects of diffraction. By using a subwavelength aperture in the near-field, however, it is possible to achieve subwavelength resolution, although low transmission through the aperture limits the sensitivity of this approach. Plasm...

Retroreflectors (RR) represent optical elements whose primary functionality is to return to the incident light back to its originating source. While inverted cube-corner (ICC) geometry constitutes de facto standard in automotive lighting applications, other RR designs exist. Among them, right triangular prism (RTP) constitutes a viable alternative...

A retroreflector (RR) is an optical device that reflects the light back to the originating source. Two of the most common types of RRs are lens-and-mirror (commonly called cat’s eye) and inverted corner cube (ICC). While lens-and-mirror RR relies on a mirror to return the incident beam, ICC makes use of its three mutually perpendicular facets to ac...

This study is focused on the evaluation of the optical performance for right triangular prismatic (RTP) geometry. In this context, a particular emphasis will be placed on its retroreflective (RR) properties to be determined by means of the correlations between design/geometric parameters and optical output. The optical performance of the RTP will b...

Retroreflective (RR) optical elements play a critical role in signaling, safety, and aesthetic/styling functionality of automotive lighting. The commonly-used inverted corner cube (ICC) RR structures with hexagonal aperture have several critical limitations that are primarily rooted in their manufacturing technique that involves complex assemblies/...

Soft-lithography techniques can be used to fabricate mechanically flexible polydimethylsiloxane (PDMS) optical waveguide sheets that act as large area light collectors (concentrators) and illuminators (diffusers). The performance and efficiency of these optical sheets is determined by the position and geometry of micro-optical features embedded in...

The controlled guidance of light rays through a mechanically flexible large area polymer optical waveguide sheet is investigated using Zemax OpticStudio software. The geometry and spatial distribution of micro-optical features patterned on the waveguide sheet determines whether the surface acts as a light concentrator or diffuser. To illustrate the...

The quality of a laser micro-polished (LμP) surface is dependent upon the part material, initial surface topography and roughness, and the energy density of the beam used to produce a thin molten layer on the finished part. Prior research has shown that the amount of energy delivered to the work piece can also be controlled by adjusting the 'focal...

The strong advent of computer-assisted technologies experienced by the modern orthopedic surgery prompts for the expansion of computationally efficient techniques to be built on the broad base of computer-aided engineering tools that are readily available. However, one of the common challenges faced during the current developmental phase continues...

Surface texture of a part or a product has significant effects on its functionality, physical-mechanical properties and visual appearance. In particular for miniature products, the implication of surface quality becomes critical owing to the presence of geometrical features with micro/nano-scale dimensions. Qualitative and quantitative assessments...

Laser polishing is presently regarded as one of the enabling technologies hoped to eventually replace the need for time-consuming and error-prone manual polishing operations which are often required by metallic surfaces. During laser polishing, a thin layer of material is being melted as a result of laser irradiation. Since molten metal is characte...

The solar energy industry strives to produce more efficient and yet cost effective solar panels each consisting of an array of photovoltaic (PV) cells. The goal of this study was to enhance the performance of PV cells through increasing the cells' optical efficiency defined as a percentage of surface incident light that reaches the PV material. Thi...

Presence of contaminants, such as gasoline, moisture, and coolant in the engine lubricant indicates mechanical failure within the engine and significantly reduces lubricant quality. This paper describes a novel sensing system, its methodology and experimental verifications for analysis of the presence of contaminants in the engine lubricants. The s...

A major limitation in terahertz (THz) imaging applications is the relatively poor diffraction limited spatial resolution. A common approach to achieve subwavelength resolution is near-field imaging using a subwavelength aperture, but the low transmission efficiency through the aperture limits the sensitivity of this method. Bullseye structures, con...

An increasing number of recent technological advancement is linked to the widespread adoptions of ultra-short picosecond (ps) pulsed laser in various applications of material processing. The superior capability of this laser is associated with the precise control of laser–material interaction as an outcome of extremely short interaction times resul...

Porous titanium, characterized by interconnected and large open-cell structures, constitutes one of the most promising bone substitutes that are currently available for surgical orthopedic and dental implantation procedures. Since little is known about the behavior of this highly porous material during material removal operations, the main objectiv...

Edge-lit light guide panels (LGPs) with micropatterned surfaces represent a new technology for developing small- and medium-sized illumination sources for application such as automotive, residential lighting, and advertising displays. The shape, density, and spatial distribution of the micro-optical structures (MOSs) imprinted on the transparent LG...

Purpose – The purpose of this paper is to develop new knowledge in experimental characterization of contaminants in engine lubricants, using surface plasmon resonance (SPR) sensing that can be applicable for on-line condition monitoring of lubricant quality and engine component performance. Design/methodology/approach – The effect of change in opti...

This paper explores the applicability of picosecond laser (ps) in laser micro polishing (LμP) of AISI H13 tool steel. The melting regime associated with this process was determined experimentally through the variation of the focal offset in order to attain a desired fluence level. To ensure the consistency and certainty of initial surface geometry,...

This work proposes a process planning for machining of a Floor which is the most prominent elemental machining feature in a 2½D pocket. Traditionally, the process planning of 2½D pocket machining is posed as stand-alone problem involving either tool selection, tool path generation or machining parameter selection, resulting in sub-optimal plans. Fo...

Polishing by laser beam radiation is a novel manufacturing process to modify the initial surface topography in order to achieve a desired level of surface finish. The performance of laser polishing (LP) is determined by an optimum combination of several key process parameters. In this regard, the overlap between two successive laser beam tracks is...

Laser micropolishing (LμP) is an innovative part-finishing process that reduces machining roughness by melting a thin layer of material on the micromilled surface using a focused laser beam. The quality of the final polished surface is dependent upon the part material, initial surface topography and roughness, and the energy density of the beam. Th...

The effect of tool orientation on the final surface geometry and quality in five-axis micro-milling of brass using ball-end mills is investigated. Straight grooves with a semicircular cross section are cut with different tool inclination and tilt angles, and the resulting surfaces are characterized using an optical profilometer and microscope. Micr...

Micro-end-milling requires high spindle rotational speed to achieve effective material removal. This results in the requirement of tool stoppage or slowdown during a micro-end-milling operation, a deterrent to productivity and to part acceptability. A circular tool path geometry can avoid discontinuities in the tool movements leading to a more cons...

Machining along continuous circular tool-path trajectories avoids tool stoppage and even feed rate variation. This helps particularly in high-speed milling by reducing the effect of the machine tool mechanical structure and cutting process dynamics. With the increase in popularity of this machining concept, the need for detailed study of a valid ch...

The solar energy industry strives to produce more and more efficient and yet cost effective photovoltaic (PV) panels. Integration of specific micro/nano optical structures on the top surface of the PV panels is one of the efficient ways to increase their PV performance through enhancing light trapping and in-coupling. In this study, periodic triang...

Edge-lit backlighting has been used extensively for a variety of small and medium-sized liquid crystal displays (LCDs). The shape, density and spatial distribution pattern of the micro-optical elements imprinted on the surface of the flat light-guide panel (LGP) are often "optimized" to improve the overall brightness and luminance uniformity. A sim...

Laser micro-polishing (LμP) is a new laser-based microfabrication technology for improving surface quality during a finishing operation and for producing parts and surfaces with near-optical surface quality. The LμP process uses low power laser energy to melt a thin layer of material on the previously machined surface. The polishing effect is achie...

Polishing by laser beam radiation is a novel technique used to modify the initial surface geometry in order to achieve a desired level of surface finish. The performance of laser polishing (LP) is determined by its process parameters, whose optimum combination is essential for the achievement of the best possible surface quality. In this regard, th...

The performance, efficiency and lifetime of modern combustion engines significantly depend on the quality of the engine lubricants. However, contaminants, such as gasoline, moisture, coolant and wear particles, reduce the life of engine mechanical components and lubricant quality. Therefore, direct and indirect measurements of engine lubricant prop...

A corner is an elemental machining feature for internal pockets that is difficult to plan and execute. During machining of a corner, there is continuous variation in radial depth of cut and frequent changes in magnitude as well as direction of the feed rate. These result in inconsistent machining leading to machine tool jerk, excessive cutting forc...

Porous titanium foam is now a standard material for various dental and orthopedic applications due to its light weight, high strength, and full biocompatibility properties. In practical biomedical applications, outer surface geometry and porosity topology significantly influence the adherence between implant and neighboring bone. New microfabricati...

Porous metals, typically produced through powder metallurgy, represent a class of relatively new materials with wide industrial applications, lately extending into the microscale domain. Although produced in near-net shapes, most components fabricated from these materials still require some form of secondary machining. Despite the progress made in...

The effect of tool orientation on the final surface geometry and quality in five-axis micro-milling of brass using ball-end mills is investigated. Straight grooves are cut with different tool inclination and tilt angles, and the resulting surfaces are characterized using an optical profilometer and microscope. Results of various cutting experiments...

Laser micropolishing (LμP) is a new advanced material microprocessing technology that attempts to smooth the original surface geometry through laser-material interactions such as melting or material ablation. Despite the significant advantages of LμP micro features, surfaces, parts, moulds and dies with complex 3D geometries from a wide range of ma...

Introduction of gasoline, water, coolant and other contaminants into the engine lubricant as well as the normal ag ing process affects the optical properties of liquid medium, such as transparency, absorption, and refractive index. A new methodology for optical analysis of contaminated engine lubricants is proposed and described in details in this...

In conventional circular end-milling practice, chip formation is generally approximated as in linear end-milling. For applications such as micro-milling, circular tool paths are used extensively in the fabrication of high-precision/quality micro features, components, parts, and moulds and dies for biomedical, optoelectronic and automotive applicati...

Machining data handbooks are important reference books in the machining industry, as they provide recommended process parameter values for common machining operations. The machining data, although covering a wide range of relevant cutting conditions, are only listed under discrete cutting conditions. Rough interpolation-based calculations are often...

A minimum limiting axial depth of cut guarantees stable machining for any cutting speed and is selected as the height of the z-level of cut used for 2 D pocket machining. It is determined based on the frequency response function (FRF) and receptance coupling substructure analysis (RCSA) to minimize experimentation. For process planning consideratio...

This article presents a systematic and logical study of the topology optimized design, microfabrication, and static/dynamic performance characterization of an electro-thermo-mechanical microgripper. The microgripper is designed using a topology optimization algorithm based on a spatial filtering technique and considering different penalization coef...

This work studies the feasibility of on-line monitoring of surface roughness in turning operations using a developed opto-electrical transducer. Regression and Neural Network (NN) models are exploited to predict surface roughness and compared to actual and on-line measurements. The comparative study suggests feasibility of using the transducer with...

This paper presents results obtained from our studies on the 3D laser micromachining and micromilling technologies. Specific examples of micro moulds and dies, fabricated using these techniques, are presented. The layer-by-layer material removal for 3D precision laser micromachining was proposed and the required process parameters were identified....

Piezoelectric polymers have been known to exist for more than 40 years, but in recent years they have been recognized as smart materials for the fabrication of microsensors, microactuators and other micro-electro-mechanical systems (MEMS). In this work, femtosecond laser micromachining of a polyvinylidene fluoride (PVDF) film, coated with NiCu on b...