Ultrasonic Finishing Research Articles

Influence of Abrasive - Free Ultrasonic Finishing Process of Steel on Wear

The intensity of wear and particles formation are important factors at practical application of rotating machine components, because of negative effects on operability of the machines. The presence of undesired wear particles, for example in lubricating systems, poses a risk in terms of subsequent accelerated wear of lubricated points. In the extreme case, the negative impact of the wear particles leads to seizure of lubricated points. The aim of the research was to compare the classical machining and abrasive - free ultrasonic finishing (bufo) of steel. Ultrasonic set I-4 consisting of the ultrasonic generator (output power 630 W) with working frequency 22 kHz ± 10% was used for preparation of test surface. There were compared three different process fluids containing nanoparticles during abrasive - free ultrasonic finishing. In order to describe machined surface there was used measurement of surface roughness, hardness HBW 2.5/187.5 and results of microscopy. Research was focused on determining resistance of machined surfaces, using a standardized test Reichert M2 tester. Number of wear particles and their morphology are important for practical application. Wear particles were analyzed by automatic particle counter LaserNet Fines-C.

Influence of Cutting Fluid on Abrasive - Free Ultrasonic Finishing of Aluminium Alloy

The aim of the research was to compare a classical (turning) machining and an abrasive-free ultrasonic machining (bufo) at aluminium alloy. An ultrasonic set I - 4 consisted of the ultrasonic generator, power output 630 W and working frequency 22 kHz ± 10%, was used for the research. Three different cutting fluids containing nanoparticles were compared at the abrasive-free ultrasonic finishing. A rise of a hardness HV0.05 and HBW2.5/62.5 compared to the classical machining occurred at the application of the abrasive-free ultrasonic machining technology at the aluminium alloy by various cutting fluids containing nanoparticles. It is obvious from the results that a considerable fall of the surface roughness parameters Ra and Rz occurred at the application using the abrasive-free ultrasonic finishing.

Improvement of Compressor Seal Assembly Elements. Part 2

A new more efficient technology for manufacturing protective sleeves is proposed, whose surface layer is subjected to integrated strengthening technology: ion nitriding, polishing, carburizing using electro-erosion alloying, and nonabrasive ultrasonic finishing. The protective sleeve material may be steel 38KhMYuA or 40KhN2MA.

STRUCTURE AND MICROHARDNESS OF TITANIUM ALLOYS AFTER ELECTROMECHANICAL TREATMENT AND ULTRASONIC SURFACE ALLOYING

The authors proposed the complex technology of surface hardening of titanium alloys based on a combination of surface alloying with boron and carbon, electromechanical treatment (EMT) and non-abrasive ultrasonic fi nishing (NUF). The results of the study of microhardness and features of the structural-phase state of the surface layer of 5V titanium pseudo-α-type alloy were presented after various combinations of treatments (EMT, NUF, surface alloying). It was shown that for a variety of schemes hardening was achieved by increasing the surface microhardness of the treated material to 30 – 40 %. The greatest effect can be observed when using alloying agent during EMT + NUF (graphite cast powder in combination with an organic binder). Increase in microhardness was provided due to the hardening by severe plastic deformation of the metal, grain size refi nement (from 50 to 1 μm) during phase transitions, as well as the formation of fi ne reinforcing borides and carbides of titanium (whose content in the surface layer increased up to 1.88 and 0.46 %, respectively).

Chromium Alloyed Steel Nitriding within Close-To-Critical Temperature Range

The paper presents X-ray diffraction and scanning electron microscope analyses, and durometer measurements used to investigate the structural properties and phase composition of nitride layers of type 20Kh13 mild steel. A method of nitriding by low-pressure arc discharge was applied along with the combined surface treatment including ultrasonic finishing and nitriding. It was shown that within the close-to-critical temperature range starting from 200oС, the nitride layers was formed on the surface of type 20Kh13 mild steel. The ultrasonic pre-treatment shown its effect on the steel nitriding that increased the amount of nitride phases and the value of microharness on the steel surface.

Interfacial Adhesion between Thermal Spray Coating and Substrate Achieved by Ultrasonic Finishing

The paper presents a pretreatment of the substrate material prior to the thermal spraying process. The ultrasonic finishing method allowed creation of a rolling topography comprising alternating projections and cavities, compressive stress, and increase of the number of defects on the surface. Optical profilometry and metallographic analysis allowed detecting of adhesion zones which form a strong physicochemical bond at the interface between the coating and the substrate material. This interfacial adhesion should provide a firm adhesion strength in end products.

Micro-Nano Burr Removing Mechanism of Precision Ceramics Surface

The micro and nano burr removing mechanism of precision surface of the nano-ZrO2 ceramics were investigated. The ultrasonic vibration finishing experiments showed that the critical ductility finishing depth of the ceramics was 3μm by conventional finishing, but the increment of the critical ductility finishing depth was 50 percent by ultrasonic finishing. The critical ductility finishing depth increased to 6μm. Analyzed by means of SEM, it was transgranular cracking during the micro-nano burr removing process. The nano-ZrO2 ceramics have high toughness so the critical ductility finishing depth increased. The shape, length, width and thickness of the finishing differed greatly from that obtained by conventional finishing.

Abrasive-free Ultrasonic Finishing of Metals

The aim of the research was to compare a classical (turning) machining and an abrasive-free ultrasonic machining (bufo) at three different materials. The surface was evaluated on the basis of an Olympus LEXT 3100 measuring of a surface roughness and hardness HV5. An ultrasonic set I - 4 consisted of the ultrasonic generator, power output 630 W and working frequency 22 kHz ± 10%, was used for the research. Main results are: increasing of the hardness HV5 of the machined surface, lowering of the roughness parameters Ra at the application of the abrasive-free ultrasonic machining, lowering of the roughness parameters Rz was not statistically proved at the application of the abrasive-free ultrasonic machining. It is possible to say according to a visual observing of the steel sample surface that a corrosive resistance was increased at the application of the abrasive-free ultrasonic machining.

Crack Resistance of Weld Seals, Hardening Methods and Composite Tools Quality

The paper presents a pretreatment of the substrate material prior to the thermal spraying process. The ultrasonic finishing method allowed creation of a rolling topography comprising alternating projections and cavities, compressive stress, and increase of the number of defects on the surface. Optical profilometry and metallographic analysis allowed detecting of adhesion zones which form a strong physicochemical bond at the interface between the coating and the substrate material. This interfacial adhesion should provide a firm adhesion strength in end products.

New Method of Friction Assemblies Reliability and Endurance Improvement

Thus a new method of shaft necks processing is suggested for practical application, including application of soft antifriction metal coating, chosen from group: indium, tin, copper, silver, which differs that the coating is applied by electroerosion alloying on the shaft neck surface with discharge energy 0,01-0,03 J in the final operation, or the coating of copper or silver is applied with discharge energy 0,04-0,4 J and subject to post-processing, for example nonabrasive ultrasonic finishing. In such cases the surface layer with the microhardness less that the microhardness of the backing is formed. That promotes the fall of friction assembly normal operation and reduces the possibility of babbit microfractures formation in cubic crystals SnSb, which subsequently become the center of fractions formation in bulk of the layer.

Experimental Study on the Surface Roughness of 40Cr by Ultrasonic Finishing Machining

The research object is 40Cr shaft parts after quenched and tempered. Optimize the main process parameters working pressure, frequency and amplitude of ultrasonic finishing. It is obtained that the various parameters influence the surface roughness of the machining samples and the optimum technological parameters combination which is consistent with experimental results. Using the SPSS software to analyze the results, obtained the process parameters impact trend of the postprocessing roughness. Contrast groups of test data, the best result was reduced by 98.4% compared with the initial roughness , reached the Ra0.04μm.

Study of microstructure of surface layers of low-carbon steel after turning and ultrasonic finishing

Profilometry and optical and transmission electron microscopy are used to examine the microstructure of surface layers of a low-carbon ferrite-pearlite steel subjected to turning and ultrasonic finishing. It is shown that turning peaks and valleys have different microstructures, which stipulates manifestation of technological hereditary when processing surfaces of machined parts. Ultrasonic finishing causes the severe plastic deformation of the surface layer, which favors the elimination of a technological heredity that is acquired during turning.

An In Vitro Comparative Study of Intracanal Fluid Motion and Wall Shear Stress Induced by Ultrasonic and Polymer Rotary Finishing Files in a Simulated Root Canal Model

Objective. This in vitro study compared the flow pattern and shear stress of an irrigant induced by ultrasonic and polymer rotary finishing file activation in an acrylic root canal model. Flow visualization analysis was performed using an acrylic canal filled with a mixture of distilled water and rheoscopic fluid. The ultrasonic and polymer rotary finishing file were separately tested in the canal and activated in a static position and in a cyclical axial motion (up and down). Particle movement in the fluid was captured using a high-speed digital camera and DaVis 7.1 software. The fluid shear stress analysis was performed using hot film anemometry. A hot-wire was placed in an acrylic root canal and the canal was filled with distilled water. The ultrasonic and polymer rotary finishing files were separately tested in a static position and in a cyclical axial motion. Positive needle irrigation was also tested separately for fluid shear stress. The induced wall shear stress was measured using LabVIEW 8.0 software.

Some features of the formation of the surface microrelief of steel under ultrasonic finishing treatment

The surface microrelief of carbon steel after ultrasonic finishing treatment was studied using a Micro Measure 3D Station three-dimensional contactless profilometer. The effect of the parameters of the initial surface on the microrelief of the obtained surface was considered. Some features of the formation of a microrelief under the regimes of hardening and finishing hardening treatment were described. To remove rehardening traces on the surface layer, introduction of a geoactivating material into the zone of treatment was proposed.

Study on Model of Ultrasonic Polishing Machining - Pulse Electro- Chemical Machining Compound Finishing for the Hard and Brittle Metals

The application of ultrasonic polishing and machining pulse electrochemical machining compound finishing is presented in the paper. The machining principle and experimental set-up of UPM-PECM compound finishing are introduced in the paper, discussing mechanism and model of the UPM-PECM in theory, and carrying on the experiment, which would co-act on hard-brittle metals in the machining. Furthermore, the material removal depth of UPM-PECM compound finishing is approximately proportional to the polishing time, and would decrease with the polishing time. This study indicates that machining velocity, machining accuracy and surface quality can be improved under UPM-PECM.

Experimental Research on Ultrasonic Assisted Pulse Electrochemical Compound Finishing for Hard and Brittle Metal

The experiment of ultrasonic assisted pulse electrochemical compound finishing is carried in this paper. The machining principle of the compound finishing is discussed in this paper. Processing experiments of compound finishing are carried out to study the effects of the main processing para- meters, including the particle size, the ultrasonic vibration amplitude, the minimum gap between the tool head and workpiece and the pulse voltage, on the material removal rate and the surface quality for hard and brittle metal materials. The curves of the corresponding relationships are also obtained. The study indicates that the processing velocity, machining accuracy and surface quality can be improved under the compound finishing, obtaining the processing technology conductions of the compound finishing. Introductions

Design of Synchronous Processes of Rolling-Leveling and Ultrasonic Electrochemical Finishing of Holes

A new finishing method of holes that uses an effective electrode and a nonconductive roller to execute the design of synchronous processes of ultrasonic electrochemical finishing and rolling-leveling is investigated. The submitted processes can be used among the traditional techniques of various holes machining. Through simple equipment attachment, ultrasonic electrochemical finishing and rolling-leveling can follow to execute the finishing process on the same machine. Among the factors affecting finishing processes, the performance of rolling-leveling combined with ultrasonic electrochemical finishing is primarily discussed. In the experiment, the electrode is used with continuous and pulsed direct current. The controlled factors include roller material, roller geometry, chemical composition and concentration of the electrolyte, and flow rate of electrolytes. The experimental parameters are frequency and power level of ultrasonics, feed rate of electrode and roller, rotational speed of the finish-tool, die material, electrical current rating, and pulsed period. The design of the synchronous processes through rolling-leveling is the most influential parameter in this study. An adequate finish-tool rotational speed produces better finishing. The average effect of the ultrasonic is better than the pulsed current while the machining time needs not to be prolonged by the off-time. An effective and low-cost finishing process through the ultrasonic electrochemical finishing and using the rolling-leveling assistance after the process of traditional holes machining make the surface of the holes smooth and bright is presented.

Synchronous Finish Processes Using Grinding and Ultrasonic Electrochemical Finishing on Hole-Wall Surface

The current study using ultrasonic energy transmitted into the electrolyte to assist in discharging of electrolytic product and cuttings out of the machining gap in the synchronous finish processes of grinding and electrochemical finishing on hole-wall surface beyond traditional process of holes machining instead of conventional hand or machine polishing. The design finish-tool includes a grinding-tool and an electrode as a hole-wall surface finish improvement that goes beyond traditional rough boring. In the experiment, the finish-tool is completely inserted to the hole; the electrode is used with continuous or pulsed direct current. The electrode form and the machining process are obviously different from electrochemical grinding (ECG). The experimental results show that the large supply of current density is effectively to reach the amount of the material removal and is advantageous to the finish processes. The finish effect is better with a high rotational speed of the finish-tool because the dregs and cuttings discharge of electrochemical finishing and grinding becomes easier and is also advantageous to the finish. The average effect of the ultrasonics is more better than the pulsed current while the machining time needs not to be prolonged by the off-time. The synchronous processes of grinding and ultrasonic electrochemical finishing just require a short time to make the hole-wall surface smooth and bright.

Compound Finish Processes Using Burnishing and Ultrasonic Electrochemical Finishing on Hole-Wall Surface

This study using ultrasonic energy transmitted into the electrolyte to assist in discharging of electrolytic product out of the machining gap in the compound finishing processes of electrochemical finishing and burnishing on hole-wall surface beyond traditional process of holes machining instead of conventional hand or machine polishing. The design finish-tool includes a burnishing-tool and an electrode as a hole-wall surface finish improvement that goes beyond traditional rough boring. In the experiment, the finish-tool travels across the hole-wall surface with continuous or pulsed direct current. The experimental results show that the large supply of current rating is effectively to reach the amount of the material removal and is advantageous to the finishing processes. The average effect of the ultrasonic is more better than the pulsed current while the machining time needs not to be prolonged by the off-time. The finish effect is better with a high rotational speed of the finish-tool because the dregs discharge of electrochemical finishing becomes easier and is also advantageous to the finish. The compound processes of burnishing and ultrasonic electrochemical finishing just require a short time to make the hole-wall surface smooth and bright.

Design of Finish System Using Rotational Magnetic-Assistance in Ultrasonic Electrochemical Finishing of Freeform-Surfaces

A new finish process that uses a rotational magnetic-assistance with high efficiency to assist discharging dregs out of the electrodes’ gap during the ultrasonic electrochemical finishing on the freeform-surfaces is investigated in the current study. The factors affecting the effects of the magnetic-assistance in ultrasonic electrochemical finishing are primarily discussed. The mainly experimental parameters are rotational speed of the magnetic-assistance mechanism, magnetic strength, distance between the two magnets, current density, and frequency and power level of ultrasonics. A large rotational speed of the magnetic-assistance mechanism produces a better finish. Providing large magnetic field intensity or using a small distance between the two magnets produces a larger magnetic force and discharge ability, and a better finish. A higher current density with magnetic-assistance reduces the finish time and avoids the difficulty of dreg discharge. The rotational magnetic-assistance during the ultrasonic electrochemical finishing process makes a great contribution in a short time by making the freeform-surfaces of workpiece smooth and bright.