Showing papers on "Surface finishing published in 1994"

Titanium alloy products and methods for their production

Abstract: A titanium alloy product having good tribological properties without the need to introduce alloy into the surface is produced by casting or casting and forging a titanium alloy consisting of 2 to 15 % by weight silicon or 5 to 15 % by weight nickel, 0 to 7 % by weight of at least one strengthening alloy selected from aluminium, tin, zirconium, vanadium, chromium, manganese, iron, molybdenum and niobium, and 0 to 2 % by weight of a surface improving alloying element selected from boron, carbon, nitrogen, oxygen and zirconium, the balance apart from impurities and incidental ingredients being titanium. Such alloy is then surface treated by surface melting and rapid solidification so as to produce a hard, wear-resistant surface layer without substantially affecting the bulk properties of the alloy. In another aspect, titanium alloy product which is resistant both to rolling contact fatigue and to scuffing comprises casting or casting and forging a titanium alloy which is preferably of the above type, to the required product shape, deep surface hardening the resultant shaped product to a depth greater than 100 νm by localised surface re-melting without further alloying, optionally surface finishing (e.g., by machining, grinding, heat-treating or shot-peening to the required final shape and/or surface finish, and forming on the immediate surface a nitride or oxide or other surface film having a thickness which is not greater than 100 νm and which is resistant to scuffing.

Polishing diamond surface

Abstract: Process of smoothing or polishing a diamond surface to reduce asperities (12) thereon to a level as low as about 20 nm from the horizontal by implanting the diamond surface with ions (10) to form a non-diamond carbon damage layer (18) on or below the diamond surface below the disparity depth and dissolving the non-diamond carbon by submerging the non-diamond carbon in a liquid having sufficient electric field to dissolve the non-diamond carbon.

Friction and wear characteristics of electroless Ni-P-PFTE composite coatings

Abstract: Electroless nickel has been used as a versatile material to protect parts from corrosion and wear. Its wear resistance has been well-established by suitable heat treatment and as a composite coating by incorporation of hard particles into the matrix. 1-5 Composite coatings, using electroless nickel as the matrix, have interested the surface finishing and engineering communities for many years. A composite coating containing silicon carbide is one of the most successful for preventing wear and for relatively low friction

Method of surface finishing a medical device shield using metallic media

Abstract: A surface finishing process for medical device shields achieves a highly scratch-resistant satin finish prior to encapsulation of the medical device within the shield. The satin finish is achieved by bead blasting the metallic substrate material with stainless steel beads before forming the final shield. The disclosed process eliminates the necessity for surface finishing the shield surface of a completed medical device.

Wood pretreatment for water-based finishing schedules

Abstract: A wood treatment process is provided that allows surface finishing with water-based wood finishing coatings without the characteristic resultant surface roughness normally associated with the use of water-borne wood finishing compositions. The wood surface is wet with an aqueous solution of an aluminum salt and preferably dried prior to application of water-based finish coatings. The process can be carried out using novel wood stain compositions comprising aqueous solutions or suspension of aluminum salts and wood dyes.

Study of Residual Stress Distribution in the Machined Stainless Steel Components

Abstract: The demand for high quality and fully automated production, coupled with advances in alloy development, focuses attention on the surface condition of products, especially the residual stresses on the machined surface because of its effect on component performance, longevity, and reliability. Although stainless steel is an important, material with wide application, it is not easy to obtain favorable surface condition, due to its sensitivity to thermal and mechanical operations. In order to obtain favorable surface conditions in a stainless steel component, it is necessary to have practical data which include information concerning tool wear, surface roughness and surface residual stress. In the research toward developing a machinability chart which can provide suitable cutting parameters for the high production rate and good quality surface, and can be used in computer controlled machining tools, surface residual stress distributions in the turning process for stainless steel were studied. Austenitic 304 s...

Experimental determination of work function of silver alloys

Abstract: Models about arc roots need a good knowledge of physical constants characterizing contact material. With pure metal, all the constants are well known; but for alloys some are not known. In this paper we relate how we have measured work function of silver alloys.

Neutral ion figuring of chemical vapor deposited SiC

Abstract: Ion figuring of optical components is a relatively new technology that can alleviate some of the problems associated with traditional contact polishing. Because the technique is noncontacting, edge distortions and rib structure print through do not occur. This investigation was aimed at determining the effect of ion figuring on surface roughness of previously polished or ductile ground ceramic optical samples. This is the first step in research directed toward the combination of a prefinishing process (ductile grinding or polishing) with ion figuring to produce finished ceramic mirrors. Multiple, chemical vapor deposited silicon carbide (CVD SiC) samples were polished or ductile ground to specular or near-specular roughness. These samples were then characterized to determine topographic surface information. The surface evaluation consisted of stylus profilometry, interferometry, and optical and scanning electron microscopy. The surfaces were then ion machined to depths from 0 to 5 micron. The finished surfaces were characterized to evaluate the effects of the ion-machining process with respect to the previous processing methods and the preexisting subsurface damage. This study provides some of the information required to effectively utilize a combined ductile grinding or polishing with ion machining as a procedure for figuring optical components.

Theoretical method for edge figuring in computer-controlled polishing of optical surface

Abstract: second peaks appear cm the right parts & the prdlles due to the increase cithe &wnward forcebetween the pad and the workpiece.2) On the basis & the changed tool removal pr&ile, the edge removal is calculated, modified functions& the dwell time are worked mit to correct the edge removal prthl..3) A group & formulus for edge problem analysis is given for ep study.

The influence of temperature and humidity on printed wiring board surface finishes: immersion tin vs organic azoles

Abstract: Substitution of lead-free solders in electronic assemblies requires changes in the conventional Sn:Pb finishes on substrates and component leads to prevent contamination of the candidate lead-free solder. Options for solderability preservative coatings on the printed wiring board include organic (azole or rosin/resin based) films and tin-based plated metallic coatings. This paper compares the solderability performance and corrosion protection effectiveness of electroless tin coatings vs organic azole films after exposure to a series of humidity and thermal cycling conditions. The solderability of immersion tin is directly related to the tin oxide growth on the surface and is not affected by the formation of SnCu intermetallic phases as long as the intermetallic phase is underneath a protective Sn layer. Thin azole films decompose upon heating in the presence of oxygen and lead to solderability degradation. Evaluations of lead-free solder pastes for surface mount assembly applications indicate that immersion tin significantly improves the spreading of Sn:Ag and Sn:Bi alloys as compared to azole surface finishes.

Simulation of Manufacturing Processes

Abstract: : This report summarizes research surrounding the simulations of two manufacturing processes-the finishing and/or repair of material surfaces and the stamping of sheet metal parts. Regarding the surface finishing project, a unified mathematical theory for the process of material removal by abrasion (grinding and polishing) was developed. Then strategies were formulated for, material removal by Operator controlled (OC) or Computer Numerically Controlled (CNC) machines. For, the sheet metal stamping project, certain asymmetric numerical solution were characterized as symmetry breaking.

Ion beam milling of silicon carbide optical components

Abstract: Silicon carbide (SiC) is emerging as an important ceramic material for optical applications requiring stiff,lightweight structures with good thermal conductivity. This report discusses the application of ion milling in thefabrication of SiC optical components. Ion beam milling combined with either ductile grinding or polishingprovides an excellent approach to deterministic fabrication of SiC optical components. Results of recent roughnessevolution studies for SIC samples prepared by several pre-ion milling fabrication processes suggest that ductilegrinding and some polishing processes can be used to produce low-subsurface-damage components suitable for ionmilling. Results are also presented of experiments in which these processes have been used in conjunction withion milling to figure SiC optical components. Typical improvements with optical figures after ion milling haveconvergences on the order of 2 or 3. Overall, these experiments indicate that ion milling combined with otherfabrication processes represents a viable, highly deterministic approach to producing high-precision SiC opticalcomponents.1. iNTRODUCTIONIon beam milling is an advanced optical fabrication process that offers a viable alternative to mechanical polishing.Mechanical polishing requires many iterations of polishing and measuring the surface to achieve figure accuracieson the order of hundreds of angstroms. Each iteration is time-consuming and costly. However, ion beam millingis a highly deterministic fabrication process. A predictable amount of material is removed; hence, as little as asingle iteration is needed to achieve the desired final surface accuracy, saving both time and money.Because ion beam milling applies no mechanical force to the optic being milled, fixturing the part is greatlysimplified. Unlike mechanical polishing, ion beam milling produces no edge roll-off or difficulty in corners and istherefore applicable to unusual component shapes. An additional benefit is that the process yields a final surfacethat is atomically clean, making it possible to coat in the same chamber used for milling. This capability makes theprocess even more economical.Because ion beam milling removes material in extremely small quantities, the optic must first be prepared bypolishing, diamond turning, or ductile grinding. If the ion beam milling process is used to remove larger amountsof material, it may uncover subsurface damage if present in the surface. The ion milling process itself does notcause subsurface damage in SiC; rather, it simply uncovers subsurface damage already present as a result of otherfabrication processes. When ion beam milling is used on prepolished chemical vapor deposited (CVD) SiC opticalcomponents, the process uncovers minor subsurface damage but is able to accurately figure optics.CVD SiC is emerging as an important ceramic material for optical applications requiring lightweight, stiffstructures with good thermal conductivity. CVD SiC thermal conductivity is 250 W/m•K, and other glass ceramicsare on the order of only 1—6 W/m•K. CVD SiC is well suited ftr many applications such as in the space andmicroelectronics industries. The Optics Manufacturing Operations Development and Integration Laboratory(MODIL) ion milling efforts have resulted in the successful figuring of CVD SiC flats and spheres.

Surface finishing method for work by using shot blasting

Abstract: PURPOSE:To form the surface of a work into an ideal condition in finish by making use of shot blasting which is a work process mainly aiming to remore corrosion products and scales, to debur, and to enhance residual stresses CONSTITUTION:This invention is concerned with a surface finishing method for a work in which shot blast injection steel beads 8 out of the tip end of a nozzle 7 are applied to the surface of the work 6 finished up by grinding in advance, conditions required by shot blasting shall be set as follows: steel bead size: 20 to 100mum, injection duration time: about 90 seconds, injection pressure: 1 to 3kg/cm , angle formed between the axial direction of a nozzle 7 and the surface of the work 6: about 90 deg, distance between the tip end of the nozzle 7 and the surface of the work: about 140mm, the hardness value of the work 6: about HV700

Reducing heat tint effects on the corrosion resistance of austenitic stainless alloys

Abstract: Arc welding can produce a heat tint on the surface of stainless and nickel-based alloys. In some services, a heat tint can decrease corrosion resistance. The conditions that cause heat tinting are discussed, and laboratory studies on post-weld cleaning procedures for removing this surface oxide scale from a 6% molybdenum super-austenitic alloy (UNS N08367) are reviewed. Cleaning can be done by either mechanical or chemical methods; a combination of both is recommended

Subsurface damage of optical components and the influence on scattering properties

Abstract: The influence of sub surface damage under smooth optical surfaces on the scattering properties was investigated. Usually this sub surface damage is filled and covered by a polishing layer. Therefore sub surface damage does not contribute to the micro roughness of the surface. Three glasses, SF3, BK7, and SUPRASIL, with different Knoop hardness and related different sub surface damage density were chosen for the measurements. Three samples of each glass were polished with increasing polishing time in order to reduce the layer which contains the sub surface damage. Beside the extensive measurements of the scatter behavior the samples were also investigated by means of microscopy (Nomarski, darkfield, cross polarization) and optical profilometry. The stray light was detected in the case of reflection (back scatter), transmission (forward scatter) and total reflection. In the case of totalreflection the scattered light behind the reflection surface was investigated. The detected scatter light was integrated over the measurement range and the resulting value was compared with the polishing time. Additional investigations were carried out to determine the influence on the light polarization.

The effect of grain-boundary devitrification on the wear of glass-bonded alumina ceramics

Abstract: The steady-state wear behaviour of a 94 wt% alumina was investigated in the as-fired condition and after a post-sintering heat treatment. The post-sintering heat treatment yielded devitrification of the 6 wt% calcia-magnesia-alumino-silicate (CaO · MgO · Al2O3 · SiO2) glass grain-boundary phase. In addition, the effect of surface finishing on the wear behaviour of as-fired and heat-treated samples was studied. Steady-state wear rates were determined using a single-pin-on-disc tribometer. The results indicated that heat treated, unfinished samples exhibit a higher steady-state wear rate than as-fired, unfinished samples. The differences observed may arise in response to one or more of the following mechanisms: (i) creation of intergranular thermoelastic stresses due to thermal-expansion mismatch among intergranular species, (ii) elimination of the lubricative glass phase in devitrified specimens, and (iii) elimination of the advantageous effects of viscoplastic deformation of the intergranular glassy phase on stress relaxation. Surface finishing further increased the steady-state wear rate of the heat-treated samples only, and it correlated with an increase in subsurface microcracking and grain pull-out. A lubricative glass film was found to persist on all sample wear tracks, suggesting that the differences in wear behaviour are dominated by intergranular fracture and grain pull-out.

Plasma etching and deposition as a method of polishing CVD diamond

Abstract: As grown, CVD diamond windows have low infra-red absorption, but are highly scattering in transmission due to the presence of crystalline facets on the material surface. Conventionally, these facets are removed by mechanical polishing techniques which are slow, not easily adapted to complex shapes, and which can lead to mechanical damage and loss of strength. In this work, an attempt has been made to use a patented plasma etching and deposition method to polish CVD diamond window material optically flat. Low pressure radio frequency (rf) discharges of a variety of plasma etchant gases (Ar, H2 CCl4, SF6, CO2) have been used to etch the diamond surface. Etch rates of 2000 angstroms/minute can be obtained using carefully optimized etch chemistries. It has been shown that plasma etching the diamond window under conditions which give a high self-induced dc bias causes preferential sputtering of the edges of microcrystallites and hence polishes the diamond surface flat. Certain plasma chemistries, notably those involving chlorine, have also been found to flatten the surface by preferentially removing the crystalline facets. By plasma depositing silicon oxide on the window material it is possible to planarize the surface prior to a plasma etch stage and then plasma etch away the silicon oxide and diamond in a subsequent etch stage so smoothing the diamond surface. The affect of these polishing methods on a variety of CVD diamond films is discussed and the limitations of the technique addressed.

Surface finishing method for inorganic porous substrate

Abstract: PURPOSE:To provide a surface finishing method for an inorg. porous substrate by which the adhesive unit stress of a metal layer formed on the surface of the inorg. porous substrate is enhanced and the formed metal layer peels hardly. CONSTITUTION:A coating film consisting of urethane resin and a permeability improver such as ethyl silicate is first formed on the surface of an inorg. porous substrate such as a cement product, a rough surface forming agent such as a mixture of epoxy resin with ceramic powder is sprayed on the coating film and then a metal layer is formed on the rough surface forming agent by thermal spraying at ordinary temp.

High Speed Milling of Turbine Blades

Abstract: The efficiency of steam- and gasturbines is mainly influenced by the geometry and the surface roughness of the turbine blades. Therefore the profile contour of the blades must be machined as accurate as possible. High speed cutting (hsc) offers a lot of advantages for surface finishing of turbine blades. The paper describes the influence of different cutting parameters as well as the importance of tool geometry for the surface quality achievable by high speed milling. Specific requirements for machine tools for high speed milling will be discussed.Copyright © 1994 by ASME

Fitting structure of wall surface finishing board and working method thereof

Abstract: PURPOSE:To reduce the manhours of boarding work of finishing boards, and to shorten the period of construction CONSTITUTION:An upper trim 2 is horizontally fixed in the upper part of a wall surface 1, and a groove 5 is formed in the lower edge of the upper trim 2 so that a gap G for inserting the upper end part of a finishing board 4 can be formed between the wall surface 1 and the upper trim A lower trim 3 is fixed to the lower part of the wall surface, and a groove 6 is formed in the upper edge of the lower trim 3 so that a gap G for inserting the lower end part of the finishing board 4 can be formed between the wall surface 1 and the lower trim The upper and lower ends of the finishing board are inserted into the gaps G formed between the wall surface 1 and the upper and lower trims 2, 3 respectively, so that the finishing board can be temporarily fixed; and after it has been positioned, the board is fixed to the wall surface 1 by means of nails or the like Since the finishing board 4 is temporarily fixed to the trims 2, 3, even in a large finishing board 4, both the positioning and fixing work can be easily carried out by one person

Surface finish of metal matrix composite under high speed turning

Abstract: Problems arising when machining metal matrix composites are the excessive abrasion of the cutting tools by the reinforcing fibres and the poor quality of the surface finishing. The aim of the paper is the investigation of the last aspect in turning operations of metal matrix composites. Face turning trials under high speed conditions were performed on SiC whiskers/2009 Al and SiC particle /2009 Al employing uncoated carbide tools characterized by a positive side rake angle. The effects of the cutting parameters on the cut surface quality are described by statistical models. The morphology of machined surface, their sections and profiles were examined by SEM and using the suitable techniques

Mirror surface finishing polishing method for carbon substrate

Abstract: PURPOSE:To provide a mirror surface finishing polishing method for a carbon substrate by which mass-processing becomes possible and the carbon board can be polished at a low cost with high efficiency by using an extremely lower- cost alumina abrasive grain than a diamond abrasive grain, and using a normally used double side polishing machine. CONSTITUTION:In a mirror surface finishing polishing method for a carbon substrate, mirror surface finishing polishing is carried out on the carbon substrate composed of a carbon material by using water, an alumina abrasive grain, and a polishing assistant. The alumina abrasive grain is obtained by dispersing a material selected from the group consisting of a pulverized alumina type abrasive grain having an average particle diameter of not more than 2mum, a hexagonal plate-like alumina type abrasive grain having an average particle diameter of not more than 5mum and a particulate alumina type abrasive grain having an average particle diameter of not more than 1mum by not more than 10weight% in polishing liquid composed of water and the polishing assistant. The polishing assistant is a water soluble inorganic substance constituting a bichromate group, a nitric acid group or a chlorine group and aluminum salt.

Protective floor member excellent in overturn safety

Abstract: PURPOSE:To improve safety by piling the basic members having a slight deflection onto a soft surface finishing member and backing the basic member by cushion members. CONSTITUTION:Under a soft surface finishing member 1 which is made of plolyvinyl chloride, etc., and has the nonslip type surface, the basic members 2 each of which consists of veneers and has a thickness of 3-15mm are piled. A cushion member 3 made of the projecting foamed body made of polyvinyl chloride, etc., is back-applied on the basic body 2, and a protecting floor member having the hardness in the turning-over collision of the max. acceleration speed G of 100G or less is formed.

Ion-beam surface treatment: a new capability for rapid melt and resolidification of surfaces

Abstract: The emerging capability to produce high average power (5 - 250 kW) pulsed ion beams at 0.2 - 2 MeV energies is enabling us to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This new technique uses high energy, pulsed ( 9 - 10 10 K/sec) cause rapid resolidification, resulting in the production of non-equilibrium microstructures (nano-crystalline and metastable phases) that have significantly improved corrosion, wear, and hardness properties. We have conducted IBEST feasibility experiments with results confirming surface hardening, nanocrystalline grain formation, metal surface polishing, controlled melt of ceramic surfaces, and surface cleaning.