Showing papers on "Surface finishing published in 2004"

System for surface finishing a workpiece

Abstract: A system is provided for finishing a surface of a workpiece, for instance by abrading a brazed area or welded area to remove excess brazed or weld material during the refurbishment of the turbine blade. A real-time control system has a controlled material removal rate strategy where a computer controls the different contact or polishing forces in real-time to achieve high accuracy.

Internal finishing process for alumina ceramic components by a magnetic field assisted finishing process

Abstract: This study presents the application of a new technique, magnetic field assisted finishing, for finishing of the inner surfaces of alumina ceramic components. The experiments performed on alumina ceramic tubes examine the effects of volume of lubricant, ferrous particle size, and abrasive grain size on the finishing characteristics. The finished surface is highly dependent on the volume of lubricant, which affects the abrasive contact against the surface; on the ferrous particle size, which changes the finishing force acting on the abrasive; and on the abrasive grain size, which controls the depth of cut. By altering these conditions, this process achieves surface finishes as fine as 0.02 μm in surface roughness ( R a ) and imparts minimal additional residual stress to the surface. This study also reveals the mechanism to smooth the inner surface of alumina ceramic tube and to improve the form accuracy, i.e. the roundness of inside the alumina ceramic tube.

Reducing surface roughness of metallic freeform-fabricated parts using non-tactile finishing methods

Abstract: Metallic parts created using current freeform fabrication processes have an unacceptably high surface finish (Ra » 1:0 mm) for many functional applications. This paper addresses the use of non-tactile laser polishing for surface finishing of commercial selective laser sintered iron±copper parts. A laser polishing window of energy density for roughness reduction up to a 37% of the original Ra value ranged between ~250 and 580 J cm-2. Several surface melting regimes are identified and analysed. The impact of oxidation on surface finish is discussed.

Surface Finishing and Evaluation of Three-Dimensional Silicon Microchannel Using Magnetorheological Fluid

Abstract: A surface-finishing method for three-dimensional microchannel structures is proposed. The method utilizes magnetorheological fluid mixed with abrasives as a polishing tool. The influences of the process parameters on the material removal were investigated, and the surface topographies before and after finishing were compared. When a microchannel was finished by proposed method, the roughness of bottom and side surfaces of the silicon channel was reduced by a factor of 5-10, and the pressure drop of a gas flow through the single microchannel was lowered to 26.7% of the pressure drop in an unfinished microchannel. The experimental results demonstrated that the proposed method was effective in finishing of microstructures.

Electrolytic processing of NiTi shape memory alloys

Abstract: The manufacturing of high-grade products made of nickel–titanium shape-memory alloys (NiTi-SMA) causes high demands on the surface finishing The disadvantage of mechanical procedures is the emerging of deformation layers, whereas thermal treatment may lead to a modification of the function properties of the NiTi-SMA in the heat-affected surface zone With electrolytic procedures it is possible to remove these zones even on smallest, finely structured components and to debur them due to the increased material degradation on the edges Therefore, this finishing process is of great importance not only for micro-system technology but also for components with elaborately manufactured structures A further field of application is the surface preparation for coating In this work NiTi-SMA of different initial topologies were electro-polished in austenitic and martensitic state and the development of roughness was recorded depending on time Satisfactory results from all initial surfaces were to be achieved However, longer polishing periods lead to the formation of waves due to material segregation Furthermore, the paper shows that the corrosive properties of a NiTi-SMA are not only dependent on the surface treatment but also on the initial topology of the surface

Methods of finishing quartz glass surfaces and components made by the methods

Abstract: Methods of surface finishing a component useful for a plasma processing apparatus are provided. The component includes at least one plasma-exposed quartz glass surface. The method includes mechanically polishing, chemically etching and cleaning the plasma-exposed surface to achieve a desired surface morphology. Quartz glass sealing surfaces of the component also can be finished by the methods. Plasma-exposed surface and sealing surfaces of the same component can be finished to different surface morphologies from each other.

Monitoring chamber walls coating deposited during plasma processes: Application to silicon gate etch processes

Abstract: During plasma etching processes, organic or mineral layers are deposited on the chamber walls. In general, these layers cause large and uncontrolled shifts in the etch process, which is becoming a major issue in some of the plasma processes used in integrated circuit fabrication. The chemical nature of these layers and their deposition mechanisms remain poorly understood due to the lack of in situ surface diagnostics available to monitor the reactor walls. In this article, we present a simple technique using x-ray photoelectron spectroscopy (XPS) analyses to monitor the chemical composition of the layer deposited on a sample floating on top of a 200-mm-diam wafer where the layers deposited are identical to those deposited on the chamber walls. The principle of the technique is to stick a small Al2O3 sample onto the 200-mm-diam silicon wafer, with an air gap between the sample and the wafer. Providing that the air gap is thick enough, the Al2O3 surface will be electrically floating even when the silicon wa...

Finishing procedure for high-performance synchrotron optics

Abstract: Modern synchrotron radiation sources of the 3rd generation like BESSY II, Spring-8 and others with their high brilliance beam characteristics need very high quality optics to exploit the full power of this radiation. For the grazing incidence reflecting type of that optics (flat, spherical or aspherical) besides roughness the slope deviation error is the most important spec, which has to be improved to meet the present and future performance requirements. Together with partners from industry we investigate and develop on the one hand surface figuring and polishing techniques for final finishing by using mainly ion beam milling technology and on the other hand we improve and make use of the combination of the surface shape measurements by means of interferometry, long trace and auto-collimation profilometry. We aim to achieve the following slope deviation errors on silicon optical elements: flat surface 310 mm long 0.03 arcsec rms, flat surface 100 mm long 0.02 arcsec rms and elliptical cylinder surface 210 mm long 0.1 arcsec rms. This is a five to ten-fold improvement compared to the present state of the art in production. To achieve the demanding specification it is necessary to measure and to deterministically machine the surface over a wide range of spatial wavelength down to the sub-millimeter range. In depth scale the sub-nanometer shape error level has to be achieved. The roughness of about 0.2 nm rms has not to be increased during the shape finishing.

Improving electrical discharge machined surfaces using magnetic abrasive finishing

Abstract: A recast layer is invariably present on surfaces produced by electrical discharge machining (EDM). For some metals with high hardness, the recast layer may contain micro-cracks. This damaged layer can affect the service life of the parts produced by this method. This investigation demonstrates that magnetic abrasive finishing (MAF) process using unbonded magnetic abrasives (UMA), can improve the quality of EDM machined surfaces effectively. The UMA used herein is a mechanical mixture of steel grit and SiC abrasive. SKD11 tool steel was used as the workpiece. Experimental results show that the recast layer and micro-cracks on EDM machined surfaces can be completely removed and a new surface of roughness on the order of 0.04 μm Ra can be produced. Additionally, experiments using the Taguchi method and L18 orthogonal array enable the determination of the optimum process conditions for improving the surface finish. Further, the significance of the control factors was identified with the assistance of...

Transmission Electron Microscopy of Boundary-Lubricated Bearing Surfaces. Part I: Mineral Oil Lubricant

Abstract: Transmission electron microscopy (TEM) was performed on the near-surface material (depth <500 nm) of tapered roller bearing inner rings (cones) that were tested at two levels of boundary-lubricated conditions in mineral oil with no additives. Site-specific thinning of cross section cone surface sections for TEM analyses was conducted using the focused ion beam (FIB) milling technique. High-resolution structural and compositional characterization of near-surface material and surface layers was performed on an untested cone as well as cones tested at Λ∼1.1 and 0.3. This approach revealed near-surface microstructural distortion and grain size gradients that were attributed to surface finishing operations during manufacture. The characteristics of oxide surface layers and micro-cracks on the tested bearing surfaces were evaluated and found to depend on lubrication conditions.

Surface finishing apparatus and related method

Abstract: An apparatus and method for surface finishing a workpiece is disclosed as including a workpiece supporting mechanism supporting a workpiece having a target shaped periphery with a given width to be surface finished and a tool holder holding a surface finish tool in abutting contact with the target shaped periphery of the workpiece. A pressure applying mechanism is operative to apply a pressure force to the surface finish tool through the tool holder to cause the surface finish tool to be held in pressured contact with the target shaped periphery, with the pressure force exhibiting a given distribution pattern depending upon an axial direction of the workpiece. A drive mechanism rotates the workpiece to allow the surface finish tool to surface finish the target shaped periphery into a given geometrical profile, variably contoured along an axis of the workpiece depending on the given pressure distribution pattern.

Surface-finishing agent and finished material and method of surface finishing

Abstract: The present invention provides a surface-treating agent to form fine roughness on the surface of a material and more specifically a surface treating-agent which forms fine roughness on the surface of a material and is easy to process, thereby being useful for materials for highly water-repellent glass, lenses and fabric, materials with an excellent anti-soiling property, panels having an excellent light scattering property, illumination of optical fiber and the like, materials and coatings to prevent accumulation and adhesion of snow or icicle formation on antennas, wires and steel towers, and roughness formation on the surface of semiconductor substrates; the treated materials; and a method of surface treatment to develop the roughness The surface-treating agent of the present invention has an average primary particle diameter in the range of 1-50 nm, contains fine particles in the range of 5-60% by mass of the total amount of the surface-treating agent in a slurry of nanoparticles which are treated for water repellency and mechanically dispersed in a solvent containing a volatile solvent, and forms a roughness structure with upward protrusions having a spatial periodicity of 01-50 μm on the surface of a material by volatilizing the solvent or dipping repeatedly in water upon treating the surface of the material

Method of manufacturing a wafer

Abstract: The present invention relates to a method of manufacturing a semiconductor wafer that includes providing a substrate of a single crystalline first material that has an unfinished or rough surface, and epitaxially growing at least one layer of a second material directly on the unfinished or rough surface of the first material. The second material has a lattice that is different from that of the first material and the epitaxial growing of the second material is advantageously performed before a final surface finishing step on the unfinished or rough surface of the substrate to increase bonding between the materials.

Discoloration related failure mechanism and its root cause in electroless nickel immersion gold (ENIG) pad metallurgical surface finish

Abstract: Electroless nickel and immersion gold (ENIG) plating is one of the common pad metallurgical surface finish for area array packages and printed circuit boards. ENIG provides a uniform coating on copper pads for excellent solderability and enhanced resistance to corrosion and wear. Nickel plays an important role as a diffusion barrier for Cu while the thin immersion gold layer over nickel protects the Ni from oxidation. This paper describes a discoloration related failure mechanism in ENIG pads. The discoloration is caused by severe oxidation of the Ni, which in extreme severity leads to electrical fails due to increased contact resistance. This paper explains the root cause for the Ni oxidation as due to the porosity of the immersion gold and the synergistic degradation of the pores during the down-stream backend and assembly's thermal and wet treatment. Optimization of the IG plating solution recipe and IG bath control parameters is necessary to mitigate the degrading impact of the downstream processes on ENIG surface finish and for elimination of the discoloration related ENIG quality issue.

Process for producing multilayer coating with high abrasion resistance

Abstract: Procedure to obtain multilayer coatings with high wear resistance, in particular for light alloy metal materials and for metal matrix composite materials, wherein the material to be coated is subjected to the following operations: a) surface deposition, using thermal spray techniques, of a first cermet coating, with thickness ranging from 20 to 600 µm; b) surface finishing treatment; c) deposition on the first coating, using vapour phase deposition techniques, of a second nitride or carbon coating, with thickness ranging from 1 to 10 µm.

Floor surface finishing device

Abstract: A floor surface finishing device includes a plane leveling machine having a plurality of rotary blades adapted to be rotated in a propeller manner by the driving force from a motor while keeping in contact with a floor surface to be finished. A planar finishing blade is connected to the planar leveling machine through a connecting member. In this state, the finishing blade is located in a portion of the outer peripheral regions of the planes of rotation of the rotary blades. Further, on the side opposite to the finishing blade of the plane leveling machine, an operating handle for the operator to manipulate the floor surface finishing device is attached. The final finishing operation on the floor surface to be finished can be conducted by placing the floor surface finishing device on the floor surface to be finished, rotating the rotary blades by the motor while pulling the operating handle to horizontally move the whole of the floor surface finishing device along the floor surface to be finished in the direction of an arrow A.

PROCESS FOR OBTAINING Y-TiAL PIECES BY CASTING

Abstract: The present invention concerns the development of a process for obtaining Ϝ-TiAl castings, with a maximum thickness of 20 mm, starting from melting charges constituted by commercially pure Ti and Al. In this process the metallic charge is induction melted in a ZrO2 ceramic crucible inside coated with Y2O3, the pouring being performed by centrifugation in ZrO2 moulds, with an Y2O3 contact coating, obtained by the lost wax moulding process. The whole sequence of operations is accomplished under argon atmosphere. The use of this process, besides avoiding the use of previously melted charges needing very specific furnaces, allows to obtain parts with homogeneous chemical composition and very low contamination with residual elements, without surface oxidation, with a hardness quite uniform from the surface to the inside of castings, which reveal a surface finishing identical to that recommended by the international standards for steel castings obtained by the same moulding process.

Experimental Equipment for Surface Finishing Precise Hole through Gas-Particle Two-Phase Swirling Flow

Abstract: Based on the basic principle of the gas-particle two-phase swirling flow finishing, the paper designs and develops the experimental equipment for the bi-directional gas-particle two-phase swirling flow finishing with the adjustable machining parameters. With the novel processing method machining parameters have preferably been determined after the careful study of the characteristics and parameters of the spherical particle, the machining time and the adjustable machining parameters of equipment under the definite condition of a machined part and its requirement. It is evidence that the ideal technique can improve the quality of the surface of precise hole and the parts operational performance after its application to the machining of cross hole and blind hole. Introduction Fig.1 shows the basic principle diagram of the gas-particle two-phase swirling flow finishing(SFF). The high-pressure air from air pump is accelerated to subsonic air flow by convergent nozzle. Since nozzle is not only tangent to inside wall of swirling head but also at an angle with the cross section of swirling head, the air flow moves spirally in swirling head and the machined hole, which makes particles revolve at high speed and forms an eccentric pressure. This kind of pressure expels particles to make scraping and scoring adhering to the hole surface, so it has the micro-grinding and rolling against the hole surface, finally aim of finishing is achieved [1]. Design of Experimental Equipment Fig.2 is a photo of the experimental equipment of the gas-particle two-phase SFF, which is mainly made up of supporting parts, forming equipment of swirling flow, clamp device, gas producer system and control system etc. According to the basic principle, machining by one swirling head will lead to asymmetry due to axial attenuation of swirling flow, so we adopt the bi-directional swirling head. The spherical particles are preloaded in the machined hole, isolating nets are installed on bi-directional air vent, which prevents the particle from outting by air flow. Through automatic control system, the bi-directional swirling head carry out alternate machining cycling, thus it leads to axial symmetry of machining effect [2-3]. z

Electrodeposition of alloys and composites with superior corrosion and electrocatalytic properties

Abstract: Tremendous potential exists for the growth of the metal finishing industry in this century through the development of processes that are either environmentally friendly or are applicable at the nanoscale. The chemical composition and the structure of electrodeposited metals, alloys and composites control their functional properties. This paper will discuss some of the theoretical and experimental studies done to achieve such coatings. Nanostructured alloys and innovative composite materials were developed through adaptation of existing bath chemistries. Process development was based on techniques developed in our laboratories such as: under potential deposition (UPD) of monoatomic metal layers, autocatalytic reduction and potentiostatic pulse (PP) plating of layers of amorphous and crystalline nanostructured metals and alloys. The development processes have been optimized based on obtaining superior corrosion and electrocatalytic properties. Further refinement of the coating process was achieved through the development of first principles based theoretical models. Electrodeposited nanostructured alloys and composites find applications in metals and the surface finishing industry. This paper will feature the development of electrochemical deposition processes to synthesize secondary and ternary alloys such as Ni-Zn-X (X=P or Cd). These materials were targeted as a replacement for Cd deposition and can inhibit corrosion and completely eliminate the hydrogen induced cracking. Electrodeposited nanostructured metals and alloys are also applicable in electronics and in the next generation of batteries, supercapacitors and fuel cell assemblies. With increasing miniaturization of electronic devices, current focus is on developing portable energy sources that can power these devices. The paper will demonstrate that pulse electrodeposition is an attractive method for controlling composite microstructure and morphology, thus yielding superior electrocatalytic properties.

Ball finishing apparatus and process

Abstract: An apparatus and process of surface finishing golf balls prior to painting is provided. The apparatus and process make use of nylon loops as a finishing material that is used to abrade the surface of adjacent moving golf balls. Optionally, the abrading process between the nylon loops and the surface of the golf balls may be carried out in the presence of a continuous stream of water. As water is removed from the processing equipment, the removed water carries with it abraded material. The process provides for improved adhesion of the paint to the surface of the golf ball.

Surface hardness increasing of iron alloys by nitrogen-deuterium ion implanting

Abstract: In situ x-ray photoemission spectroscopy is used to study the deuterium and hydrogen oxygen etching effect in nitrogen-implanted iron alloys. A suitable deuterium-nitrogen mixture can increase the surface original steel hardness up to ∼40%. In similar conditions, hydrogen-nitrogen mixtures improves the hardness by ∼10%. On deuteration, the main change is the reduction of the zero-point energy of the hydrides bond. Due to this, the lower scission energy of hydrogen-metal bonds as compared with deuterium-metal bonds determines the favorable effect of deuterium on the nitriding process.