Ceramic Spindle Research Articles

ОРУДИЙНЫЙ КОМПЛЕКС АЛАКУЛЬСКОГО НАСЕЛЕНИЯ ПОСЕЛЕНИЯ ЗОЛОТОЕ-1 В ЛЕСОСТЕПНОМ ПРИТОБОЛЬЕ

The article presents the results of a typological and experimental traceological study of the tool complex of the Alakul time of the Zolotоe-1 settlement, located in the Tobol-Ishim interfluve. About 40 items made of stone, clay, bone, and bronze have been analyzed. As a result, the range of products has been determined and the functional purpose of most of them has been established. The tool complex includes ceramic spindle whorls, hammers for forging, passive tiles for grinding and grinding, piercers, blunt axe, agalus, etc. The inventory set finds numerous analogies in Alakul and other Bronze Age and later Bronze Age sites. It is concluded that the Alakul population in the area of the village was engaged in the processing of leather, metal, stone, bone, the manufacture of dishes, spinning — the main industries characteristic of the pastoral tribes of the Late Bronze Age (the authors adhere to the Eastern European chronological scale). Thus, the conducted studies made it possible to supplement the characteristics of the livestock economy of the Alakul population with data on production activities and confirm the earlier conclusions about the absence of differences in the traditions of farming among the population living along the rivers and in the interfluve.

Nonlinear dynamic analysis of ceramic motorized spindle considering bearing preload and span

Ceramic motorized spindle is more suitable for high-precision and high-speed machining because of its material with high stiffness, low deformation, and other excellent characteristics. The ceramic bearing assembly and support location are critical elements influencing the stiffness and dynamic characteristics of ceramic motorized spindle. In order to investigate the influence of bearing assembly on the dynamic characteristics of spindle, the relationship between preload and bearing stiffness is determined and a dynamic model of ceramic motorized spindle bearing rotor system is established taking the comprehensive impact of bearing span and preload into account. The bearing stiffness fluctuation caused by bearing preload and bearing thermal deformation is calculated, and the effect of bearing preload and span on the dynamic characteristics is investigated. The results show that the rotor amplitude firstly decreases with the bearing preload and span vary, and then increases. The best assembly combination of ceramic spindle is a preload of 400 N and a span of 190 mm in the speed of 12,000–18,000 r/min. The vibration experiments are conducted on the ceramic motorized spindle, and the average error between experimental date and calculated date is 2.49%, which verifies the accuracy of the model. This study lays a theoretical foundation for further investigation of the dynamic characteristics of ceramic motorized spindle and its structural optimization.

Analysis of dynamic characteristics of ceramic spindle considering the thermal magnetic coupling effect

The ceramic spindle rotor system is widely used in CNC machine tools. However, the dynamic characteristics are influenced by the magnetic forces and thermal deformation, which leads to the reduction of running accuracy. In this paper, the thermal deformation of the rotor system are calculated, and the magnetic field distribution is obtained based on the Maxwell theory. The thermal magnetic coupling effect is then analyzed to investigate the interaction between thermal deformation and magnetic force, and the impact of thermal magnetic coupling effect on the dynamic characteristics is obtained. Experiments are conducted to verify the simulation results, and the dynamic characteristics with and without consideration of thermal magnetic coupling effect are compared. Results show that the thermal deformation and magnetic force have nonlinear increases with speed, and the model considering the thermal magnetic coupling effect has a higher accuracy with the error decreased by 4%. The air gap is a key factor that determines the dynamic characteristics of the ceramic spindle rotor system, and a larger air gap can help lower the vibration at high speed. This study provides a theoretical basis for the structural design of ceramic spindle rotor system.

THE BARROW OF THE EARLY IRON AGE NEAR MOTRONYN HILLFORT

In 2019, the Scythian Right-bank expedition organized by the Institute of Archaeology of the National Academy of Sciences of Ukraine and the National Historical and Cultural Reserve «Chyhyryn» excavated the barrows on the Motronyn hillfort suburb, located near Melnyky village, Chyhyryn district, Cherkasy Region, in the south of the Forest-Steppe of Dnieper Right-bank area.
 The barrows were erected in pre-Scythian Age and the barrow 97 also contained the inlet Scythian burial. This mound was 0.65 m high, the diameter was 8.8—9.8 m. A pre-Scythian burial-memorial complex was discovered under the mound, destroyed by a later burial. Finds from it are represented by fragments of ceramic ware: pots, large earthenware pots, bowls, ladles. Some fragments are decorated with geometric patterns. Ceramic spindle whorls, iron knives, bronze arrowheads, plaques, and animal bones were also found.
 During the Middle Scythian period another deceased was buried in the center of the mound. The tomb had the shape of a rectangular pit, oriented along the west — east line. Its length was 1.89—2.16 m, width — 0.7—0.82 m, depth from the surface of the mound — 1.45 m. The skeleton laid supine, with its head to the west. The left leg was lying on a stone slab. A quiver with arrows was placed next to it. An iron sword and a knife with a bone handle were found near the belt. This burial was also accompanied with the laying of wares in the mound borders. A pot was buried in the north, and handmade and wheel-made bowls in the east.
 Pre-Scythian finds from the mound have analogies in different regions of the Ukrainian Forest-Steppe where antiquities of the Late Chornoliska and Zhabotyn cultures are widespread, in particular on the Middle Dniester and in the Southern Bug River region, on the Right-bank of the Dnieper and in the Vorskla River region. A set of pottery and an arrowhead of the Novocherkassk type allows us to date the mentioned assemblage by the second half of the 8th century BC.
 Funeral rite and grave goods of the Scythian Age burial also have parallels in the sites of that time, including the south of the Right-bank of Middle Dnieper. According to the pot type and arrowheads, this burial can be dated to the second half of the 6th century BC.

Study on vibration characteristics of motorized spindle based on multi-physics fields

Ceramic motorized spindle plays an important role on CNC machine tool. Its dynamic characteristic determines the machining quality of spindle. This paper established a dynamics model of ceramic bearing, and explored the relationship of bearing stiffness and vibration response. The temperature field model of ceramic motorized spindle was established to analyze the temperature field. The motorized spindle air gap influence on unbalanced magnetic pull was studied. The dynamic model of ceramic motorized spindle was established through considering the multiple physical fields influence factors, the changing law of dynamic characteristics was studied. It has been verified by experiments. The average error of ceramic spindle decreased from 5.1% to 2.1%. The establishment of multi-fields dynamic model provided an important guidance for spindle design.

Research on Ceramic Spindle Loss Based on Ceramic Reverse Magnetic Effect

Ceramic motorized spindle is a multifield, nonlinear, and strong coupling system. The present model ignores the reverse magnetic effect and has a poor accuracy on the loss of the spindle system. In the paper, Park transformation was used to establish the electromagnetic physical model of ceramic motorized spindle. By combining with the Jiles–Atherton theory, an eccentric magnetization model of a ceramic motorized spindle considering reverse magnetic properties was established. Energy consumption parameters were calculated under various working conditions. The influence of ceramic reverse magnetic characteristics on the motorized spindle loss was analyzed and verified by experiments. The results show that the simulation of the ceramic motorized spindle loss model is in good agreement with the experimental results. Compared with the experimental results, the average loss error was 2.1%. Due to the reverse magnetic characteristics, the application of ceramic motorized spindle can help reduce the system loss. The ceramic motorized spindle model provides a theoretical basis for the development of ceramic spindle energy loss and efficiency.

A Female Burial with Gold Jewellery from the Ust’-Al’ma Necropolis (Crimea) Dating from the 1st Century AD

Abstract This is the publication of a female burial in Catacomb No. 1119 of the Ust’-Al’ma necropolis situated on the south-western shore of the Crimea. In it were found items of personal jewellery (gold earrings, amphora-shaped pendants, beads of a necklace and plaques originally sewn on to garments) as well as grave goods (gold leaves from a funerary wreath, gold eye-pieces, two hand-moulded ceramic incense-burners, a ceramic jug, an iron knife, a ceramic unguentarium of the bulbous type, a ceramic red-slip bowl and two ceramic spindle whorls). The grave might have belonged to a representative of the social élite and it dates from the first half of the 1st century AD.

Research on Vibration Characteristics of a Ceramic Spindle Based on the Reverse Magnetic Effect

The electromagnetic radial force about a ceramic spindle affects the spindle dynamic, which determines the quality of processing. Using a Timoshenko beam unit to build the dynamic model for the ceramic spindle, the dynamic characteristic of an angular contact ball bearing is analyzed using a nonlinear bearing model. The electromagnetic magnetization model was established based on Maxwell’s theory to calculate electromagnetic magnetic density and radial force. The influence about the reverse magnetic field characteristic of the ceramic rotating shaft and dynamic stiffness of the contact ball bearing on the dynamic phenomena of the spindle is analyzed, which is verified by experiments. The results show that the magnetic effect produced by the reverse magnetic of ceramic rotation shaft has a great influence on the electromagnetic radial force. Compared with the paramagnetic effect of the metal shaft, the dynamic characteristics of the spindle can be significantly improved. Considering the coupling relationship between the radial force of the magnetic field and the bearing contact force, dynamic stiffness, and other factors, the accuracy of the model simulation is highly consistent with the test results. In particular, the ceramic spindle model has been successful in predicting with high accuracy and is suitable for multiple extreme working conditions. The parameters, such as initial eccentricity of the rotor, bearing preload, and rotating speed, can be adjusted to restrain the vibration of spindle. The ceramic spindle model provides a theoretical basis for the dynamics development of a high‐speed spindle.

Spindle Whorls of Late Trypillia – Troy(aniv) and Troy

Trypillian ceramic spindle whorls are a poorly understood category of artifacts. They do not even always fall into the general reviews of Trypillian materials. This type of items is widespread and is typical for the late stage of Trypillia (CII). More than 200 spindle whorls were found in the Troianiv settlement. Dozens of these items were obtained during the excavation of such settlements, as Pavoloch, Horodsk and others. Contextual analysis of the spindle whorls finds shows that most of them originated from the ruins of burnt dwellings. In many late Trypillian settlements, they are found in pits, which can be interpreted as religious objects. Finds of these items are also well known in the Kasperivtsi cultural layer of the Verteba cave, recognized as a sanctuary. In addition, spindle whorls were part of the funeral gifts in the Vykhvatyntsi necropolis. In Kolodyste they were discovered in graves placed under the barrow. Here they were located in pots, full of calcinated human bones. In other case a spindle whorl was placed in ashes at the necropolises of Sofiivka group. Formal analysis of spindle whorls shows the diversity of their types, which do not form any groups. The shape, measurements and weight did not affect their technological properties. A significant amount of them is decorated with a deepened decor, and certain ornamental patterns are common to all the locally-chronological groups of Trypillia C II. The exterior view of spindle whorls, the context of their finding and the symbolic decoration makes it possible to consider them as religious objects. Their decoration isn’t connected technologically with their manufacturing. The tradition of spindle whorls usage in Trypillia C II arises along with the phenomenon of “badenization” of this culture at the beginning of the Early Bronze Age (EBA). The common features of Trypillia C II items and finds from the Troy’s EBA layers allows seeking answers to the question of the spread of sacral traditions in the Old World.

Experimental Research on High Speed Grinding of Silicon Nitride Ceramic Spindle

Grinding is a main method of silicon nitride ceramic in finish machining stage. The technical parameters had an important influence on the surface quality of silicon nitride ceramic. The silicon nitride ceramic spindle was ground by the high-speed cylindrical grinder MGKS1432-H. The relations between different speed parameters and surface roughness were researched. The cylindrical and internal high speed grinding experiments of silicon nitride ceramics spindle were carried out. The S-4800 scanning electron microscope was used to explore the roughness change rule of the grinded surface under the condition of only changed grinding wheel’s velocity. In the process of cylindrical and internal grinding on silicon nitride ceramic spindle, the roughness tended to decrease with the linear velocity increasing, and increased with the radial feed speed increasing and decreased with the wheel shaft’s oscillation speed increasing. The result indicated that the linear velocity of grinding wheel influenced the sample’s roughness most. The effect of radial feed speed on the roughness is next only to the effect from linear velocity. The effect of shaft’s oscillation speed on the roughness is the lowest of the three factors. In the process of internal grinding, with the linear velocity increasing, the ceramic material transformed from brittle rupture to plastic deformation and the roughness appeared one peak. These results were very helpful to optimize the grinding parameters and improve grinding efficiency.

Research on Application of Advanced Ceramics in Machine Tool Spindles

One important demand on spindle systems in modern machine tools is to realize higher rotational speed in order to increase the machining efficiency. So, the low rotational inertia and high fundamental natural frequency are indispensable. Because of advanced ceramics' extraordinary physical properties such as high hardness, low thermal expansion, light weight, abrasion resistant and good chemical and thermal stability, it accommodates very well the high-speed and precision requirements of machine tool spindles. In this study, a high-speed ceramic spindle system equipped with high-performance structural ceramic shaft and fully-ceramic ball bearings was designed and developed. The high-speed ceramic motorized spindle prototype was assembled with high precision successfully, and its performance test and analysis were finished. The test results show that ceramic motorized spindle can reduce the high-speed rotational centrifugal force and inertia force and increase the stiffness and rotation accuracy of spindle-bearing system greatly.

Analysis about the Influence of Load on Loss of the Ceramic Spindle

The increase of loss causes the temperature rise in motor, reducing the using life of spindle, which can seriously affect the performance of motor. Thus, accurate calculating of loss is meaningful to optimal design of electric spindle. In this paper, the losses both with load and without load were analyzed by time-step finite element method. As the result of simulation analysis, the spindle losses with load are higher than those without load. Comparison analysis indicates that losses are various with different load. And the load impacts on core loss mostly in ceramic spindle. In addition, in asynchronous ceramic spindle with 4N•m rated load, the core loss, solid loss and stranded loss are least when the load change from 1.8 N•m to 3.8N•m. Accordingly, the best operation condition under the influence of load in electric spindle is gained.

Analysis of Influence to Electric Spindle Losses Caused by Carrier Ratio in Frequency Converter

Aiming at analyzing the influence to ceramic electric spindle and metal electric spindle caused by carrier ratio in frequency converter, in this paper, the time-step finite element model was built based on SPWM method. The changing law of the loss in different carrier ratios were gained by simulation. The result shows that the greatest impact by carrier ratio is solid loss, the least is core loss. The ceramic electric spindle is less impact by carrier ratio than metal electric spindle. Additionally, the corresponding carrier ratio with minimum loss in both ceramic electric spindle and metal electric spindle were found.

The Accuracy Analysis on the External Circular of Zirconia Ceramic Spindle by Precision Machining

The high-speed ceramic electric spindle is applied in high-speed NC machine tools. Now the technology of ceramic spindle with its excellent performance applied to electric spindle is becoming a kind of important development trend. Each surface processing accuracy requirement of high-speed ceramic electric spindle is high. The performance of the electric spindle in largely determines machining precision and production efficiency of the high-speed machine tool. In order to meet the requirements of high speed, high accuracy, high reliability and small vibration in the rapid processing of machine tool, it is necessary to make a rigorous precision testing for the precision-processed spindle and obtain reliable data to meet the design standards and performance requirements of all ceramic high-speed spindle. This paper focuses on the research of surface roughness, roundness and cylindricity analysis of spindle external circular, which can make the precision-processed zirconia ceramic spindle pore to meet the design requirements and provide reliability safeguard to promote the using life and high-speed dynamic balance stability of the whole electric spindle.

The Inner Hole Precision Detection of Precision Machining Zirconia Ceramics Spindle

The high-precision component named full ceramic high-speed electric spindle is used in high speed NC machine tools. Electric spindle have very high demand for the stability and dynamic balance of ceramic spindle when high-speed rotation. In order to ensure the smooth operation of high-speed spindle and realize the dynamic balance of the spindle, it is necessary to make a rigorous precision testing for the precision-processed spindle and obtain reliable data to meet the design standards and performance requirements of all ceramic high-speed spindle. In this paper, contact Surtronic25 type roughness measuring instrument is used for surface roughness analysis, and Leitz ultra PMM-C12.10.7 type tri-ordinate measuring machine is used for the roundness and cylindricity testing analysis of spindle hole, which can make the surface roughness, roundness, and cylindricity of the precision-processed zirconia ceramic spindle pore ​​to meet the design requirements and provide reliability safeguard to promote the using life and high-speed dynamic balance stability of the whole electric spindle.

The External Circular Precision Detection of Precision Machining Zirconia Ceramics Spindle

The electric spindle is the main form of high-speed NC machine spindle. Now the technology of ceramic spindle with its excellent performance applied to electric spindle is becoming a kind of important development trend. The performance of the electric spindle in largely determines machining precision and production efficiency of the high-speed machine tool. In order to meet the requirements of high speed, high accuracy, high reliability and small vibration in the rapid processing of machine tool, it is necessary to make a rigorous precision testing for the precision-processed spindle and obtain reliable data to meet the design standards and performance requirements of all ceramic high-speed spindle. In this paper, contact Surtronic25 type roughness measuring instrument is used for surface roughness analysis, and Leitz ultra PMM-C12.10.7 type tri-ordinate measuring machine is used for the roundness and cylindricity testing analysis of spindle external circular, which can make the surface roughness, roundness and cylindricity of the precision-processed zirconia ceramic spindle pore ​​to meet the design requirements and provide reliability safeguard to promote the using life and high-speed dynamic balance stability of the whole electric spindle.

The Inner Hole Grinding Surface Roughness Analysis of Zirconia Ceramics Electric Spindle

The high-speed ceramic electric spindle is applied in high-speed NC machine tools. Each surface processing accuracy requirement of high-speed ceramic electric spindle is high. The inner hole surface roughness is the key factor which affects its high-speed stability and moving accuracy. This paper focuses on the research of the relationship between inner hole and grinding wheel granularity and grinding wheel linear velocity and transverse feeding and grinding camber ratio through the experiment of diamond wheel grinding the inner hole of ceramic spindle. The optimal grinding parameter combination of ceramic spindle inner hole grinding is obtained. The surface roughness of ceramic spindle inner hole reaches 0.21μm, through the analysis of orthogonal test. The results can completely satisfy the ceramic spindle high-speed operation requirements and enhance the ability of corrosion resistance and fatigue damage resistance. It then improves the whole work performance, reliability and life of ceramic spindle.

Vibration and Noise Monitoring of Ceramic Motorized Spindles

High speed machining (HSM) technology is used in a broad range of applications to machine ferrous metals and nonmetallic material. The motorized spindle is one of the major elements to keep the machine running at high productivity. In recently years, the requirement of rotational speed and rigidity of motorized spindle is getting higher and higher in order to satisfy the high speed processing. Engineering ceramic is the ideal material for high-speed and high precision electrical spindle due to perfect characteristics of light weight, wear resistance, high temperature, high strength, and so on. So a ceramic motorized spindle is designed for higher speed and rigidity. The shaft and bearing of the motorized spindle are made from ceramic material and other parts are made from metal. Rated power of this electrical spindle is 15Kw; its torque is 14Nm and revolving speed is up to 30,000 rpm as maximum. Motorized spindle is a typical mechatronics product and its dynamic property is very important. The signal of vibration and noise of motorized spindle may display its running status, so the vibration and noise of motorized spindle is an important index in the dynamic performance. This paper monitors the vibration and noise of ceramic motorized spindles using spectral analysis techniques. The effects of rotating speed and lubrication condition on vibration and noise of the ceramic electrical spindle are analyzed. These results are very helpful to the structure optimization and application of the ceramic motorized spindle.

Analysis about Vibration and Noise of Ceramic Electrical Spindle

High speed machining (HSM) technology is used in a broad range of applications to machine ferrous metals and nonmetallic material. The electrical spindle is one of the major elements to keep the machine running at high productivity. In recently years, the requirement of rotational speed and rigidity of electrical spindle is getting higher and higher in order to satisfy the high speed processing. So a high speed grinding electrical spindle equipped with hot isostatic pressed silicon nitride (HIPSN) fully-ceramic ball bearings without inner rings and yttria partially stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic spindle shaft is designed for higher speed and rigidity. Because the processing precision is relevant to the vibration of electrical spindle, it is necessary the vibration and noise of the ceramic electrical spindle is detected. This paper presents results of vibration and noise of the ceramic electrical spindle and analysis the reason of phenomenon. The analysis shows the vibration and noise of the ceramic electrical spindle is up to the standard.

Parameter Optimization for Oil/Air Lubrication of High Speed Ceramic Motorized Spindle without Bearing Inner Rings

Recently, hybrid ceramic bearings and oil/air lubrication have been used more and more on high speed spindles. However, applying an appropriate lubrication and the hybrid bearings can’t be overemphasized, and the oil/air supply with inadequate parameters is undesirable. In this study, a high speed ceramic spindle equipped with HIPSN (Hot Isostatically Pressed Silicon Nitride) full-ceramic ball bearing and Y-TZP (Yttria partially stabilized Tetragonal Zirconia Polycrystal) ceramic spindle shaft was designed for higher speed, stiffness, precision and longer operating life. Furthermore, the performance of a high-speed ceramic motorized spindle under different lubrication parameters was investigated. The optimum lubrication conditions that create the smallest temperature increase were obtained by the applying of the Taguchi method. The results show that oil volume per lubrication cycle, interval time per lubrication cycle and air pressure are three pacing factors that affect the temperature increase most significantly in ceramic motorized spindle with oil/air lubrication.