Female Screw Research Articles

Using a frequency vibration approach, examine the impact of screw rotor clearance on the screw housing in an 11kW compressor

A screw compressor is one of the industrial machines needed for productivity and use in today's production. Industrial machines generally use pneumatic systems with the help of compressed air supplied by a compressor machine. The compressor working system must receive very special attention. Maintenance and prevention of damage to air screw compressor machines is very necessary, especially maintenance and prevention of damage to rotary screw air compressors. Problems that often occur with the shaft will result in reduced air supply flow or unstable air pressure resulting in disruption of the production line. The aim of this research was to discuss the vibration values produced against the rotor clearance from the ideal output on male and female screw compressor rotors using the frequency analysis method, taking the vibration values at the screw compressor housing point using an Accelerometer sensor and a Fast Fourier Transform (FFT) tool. The analyzer rotates at 1500 rpm in the X, Y and Z axes at each predetermined point. Research shows that the clearance is set at 0.03, 0.05 and 0.08. In this research, the high frequency sample values of 1x 25 Hz, 2x 50 Hz, and 3x 75 Hz often appear in each vibration data of 0.03 and 0.05, at the vibration frequency range value of 0.08 none appear. This shows the results that the ideal rotor clearance value is at a distance of 0.08 because there is no frequency graph of 1x, 2x, and 3x rpm at each point and axis on the end housing of the screw rotor compressor

Development of Vibratory Microinjection System for Instantaneous Cell Membrane Piercing in Cytoplasmic Microinjection into Fertilized Eggs

To complete microinjection as quickly as possible, we have developed Vibratory Microinjection Systems (VMSs) that vibrate a micropipette in its longitudinal direction and can significantly reduce the time needed for pronuclear microinjection compared to ordinary (non-vibratory) microinjection. The longest breakdown of the time is the time required to pierce the cell membrane and the pronuclear membrane simultaneously. Because cytoplasmic microinjection, which pierces the cell membrane alone, is far more difficult and time-consuming than pronuclear microinjection, we next aimed to develop a VMS capable of penetrating the cell membrane instantly. In this new and latest version, two types of ultrasonic-wave vibrators were developed: the first for commercially available micropipettes (Femtotip) and the second for self-made micropipettes. The two vibrators differ only in their airtight structure, where the micropipettes connect to their respective vibrators: a female screw plus O-ring for the first vibrator (VMS6_1) and a silicone–-rubber tube for the second (VMS6_2). The tube-type joint used in VMS6_2 only slightly damped or amplified vibrations from the vibrator to the micropipette tip, propagating them much more accurately than the screw-type joint in VMS6_1. In addition, VMS6_2 significantly shortened the time taken to pierce the cell membrane of a fertilized egg: an average of 1.52 s (N = 410) vs. 3.62 s (N = 65) in VMS6_1. The VMS6_2 group achieved a piercing time of zero in 86.1% of the allocated eggs, while only 10.8% of the VMS6_1 group did. In each vibrator, we also compared vibratory microinjection (VM; N = 475) and ordinary microinjection (OM; N = 457), which uses injection pressure in place of vibration. None of the eggs in the OM group achieved the zero-second piercing time. Compared to the OM, the VM group showed a significantly shorter piercing time, 1.80 vs. 10.69 s on average, and a significantly better survival rate, 90.3 vs. 81.8% on average. VMS6_2 not only improved on the already demonstrated superiority of VM to OM but also enabled instantaneous piercing of the cell membrane.

Analysis of the market of mine support systems in Russia

The analytical results on the current condition and growth prospects of the market of mine support systems in Russia are presented. The scope of the analysis involved all available and open sources of information: databases of the Federal Customs Service and of the Federal Service for State Statistics of the Russian Federation; regulatory documents in open access; printed and electronic business materials and analytical reviews; global Internet; expert inquiries; information provided by the participants of the domestic and international markets; research data of marketing and consulting agencies; databases of sectoral institutions; pricing monitoring results; research papers and proceedings of scientific conferences. The present-day business climate in the mining industry in Russia is assessed. The major importers of mine support systems and the average price dynamics of the relevant imports for the last 5 years are identified. The vulnerable spots are detected on the Russian market, namely, the lack of the pre-feasibility study procedures of new, innovative and expensive systems and types of mine support; the lack of testing machines to estimate and demonstrate operation of different mine support systems and types under static and dynamic loading with a view to determining their energy absorption capacity and deformation characteristics, etc. The mineral resources and mineral reserves of Russia are evaluated per regions of the country. The information on production of mine support systems in Russia is given together with the review and characteristic of the suppliers, as well as with the procedure and sequence of mine support system certification in Russia. The manufacturers of sheet and rolled products, metal (forged) female screws, special structural iron and H-beams are listed. Based on the analytical results on the market of mine support systems in Russia, at the current stage of development of the mining industry, the Russian manufacturers and suppliers of mine support systems have good prospects for the effective internal marketing of the products and for engineering of innovative systems and materials. These prospects are for the first turn connected with: the ability to completely supply production with domestic rolled products, structural iron and other required materials; the elimination of imports of such products from unfriendly countries; the stiffening of the government supervision over safety in mining; and with the concern of the scientific community in Russia for engineering and design of novel and nonstandard mine support systems for different geological and geotechnical conditions. The 2021 Report on the Market of Mine Support Systems in Russia and Kazakhstan includes a substantial volume of statistical data on all essential areas and topics. The report is available on request at the Research Center for Applied Geomechanics and Convergent Technologies in Mining of the NUST MISIS’ College of Mining.

The Screw Threads of Antiquity: To Raise, to Adjust, to Measure, to Press, and to Hold

The screw in antiquity took many forms suitable to an equally wide range of functions. Where pressure was to be exerted or a firm union achieved, both male and female screw threads were necessary. These were rarely produced in metal in the remote past. This paper describes a number of Late Roman crossbow brooches with tapering threaded pins and brass demountable lampstands or candelabra where the components were held together by a male screw engaging with the corresponding female screw. The way should have been open for the development of the familiar nut and bolt. Instead the succeeding demountable lampstands were held by much simpler bayonet fitting, and screws and bolts as known today had to wait for another thousand years.

Female Screw Forming of Aluminum Alloy A7075 by Semi-solid Forging

Female Screw Forming of Aluminum Alloy A7075 by Semi-solid Forging

The Use of Optical Methods in the Analysis of the Areas with Stress Concentration

Abstract Anchoring parts of technical systems are often damaged due to the heavy forces acting on these systems during their operation. For that reason, various modifications are suggested and created on the anchoring screws, which should help to reduce the mechanical stress values in a place of the first load-bearing thread of a female screw. For the determination of stress fields on the surface of a plane model of a threaded joint, two non-contact optical methods were used – conventional transmission photoelasticimetry and modern digital image correlation.

Profiling disk tool for generating female rotor screw compressor component by meaning of graphical method

The paper proposes a method of profiling the disk tool generating the helical groove of the female rotor of the compressor, on the basis of a complementary theorem of enveloping surfaces, e.g. theorem "Substitution Circles Family", whose principles are developed in analytical way. On the basis of this theorem is proposed a method developed in the graphical environment Auto-CAD, in purpose to design the disk tool for profiling the female rotor and also to determinate the front view profile of this rotor, screw compressor component. Has been also detailed a numerical example for a known built compressor.

Unusual Structure and Fabrication Process of Japanese Matchlock Gun (Hinawajuu), Made at the Late EDO Period

The metallurgical macro- and micro-structure, and the residualstress of the Japanese matchlock gun, fabricated at the late Edo period, have been investigated with an optical microscope, an SEM, an EPMA and an X-ray residual stress meter for estimating the fabricating process and their materials. This gun was fabricated by Udonbari (in Japanese) process, which is similar to that of the Russell's method, tubes was created by the joining together opposite edges of a flat iron strip with an iron core bar. The joining line was wavy. Their residual stress was mainly compressive and the values were from 180 to 280 MPa in the longitudinal direction and from 240 to 380 MPa at the transverse direction.The gun was made of low carbon steel with equiaxed ferrite grains; their grain size was mainly 10 μm partly with 100 μm and exceptionally more than 1000 μm grains. Moreover, we find the special banded structure, consisted of fine ferrite grains bands and large ferrite grains bands.The firing part was fabricated by the joining of five parts for getting the L-shape hole. The female screw was made by forging; therefore the shape was tapered screw and the male screw was cut from a low grade steel bar, confirmed by their macro-structure.

A study on thick plate forming using flexible forming process and its application to a simply curved plate

In this study, design and fabrication of a flexible forming machine are carried out for the purpose of manufacturing a prototype of curved plate block for hull structure used in shipbuilding industry. Flexible forming dies which consist of numbers of punches in an array form for upper and lower sides are designed in view of thick plate forming. A punch has formation of male and female screws to adjust its length with regard to a given surface, and all punches are supported by each other in punch housing. Software for process configuration and punch control are developed to operate the novel flexible forming machine. The software are composed of the punch height calculation part which uses an offset surface scheme. Prior to manufacturing of a prototype, numerical simulations for a saddle-typed thick plate forming process including metal forming and spring-back analyses are carried out to predict the forming performance. Experiments are also carried out to validate and confirm the feasibility of flexible forming technology in view of practical application of thick plate forming process. Curvature radii observed in the simulation and experiment are investigated and compared. Consequently, development and practical application of flexible forming technology to the thick plate forming process are described from design of the forming machine to manufacturing of the prototype. It is confirmed that the flexible forming technology suggested in this study has enough feasibility in new application of thick plate forming in shipbuilding structures which has been formed through expensive and laborious conventional line heating.

A Case of Accidental Hypotension Caused by Drug Leakage through the Rubber Piston in a Prefilled Inovan Injection 0.3% Syringe

A Case of Accidental Hypotension Caused by Drug Leakage through the Rubber Piston in a Prefilled Inovan Injection 0.3% Syringe

Performance Assessment of Surface Finishing Using Completely Inserted Module of Female-Screws

It is very difficult to execute the finishing process of the concavo-convex surface of female-screws. The current study offers a screw-form design electrode and a new area-finishing process using an ultrasonic generator. The ultrasonic energy generated is transmitted into the electrolyte to assist the process of electrochemical finishing. The surface of female-screws is electrochemically finished by different types of completely inserted electrodes and put through both continuous and pulsed direct current as a finishing operation. For inserted screw-form electrodes, a smaller circumference electrode on the cylinder provides more sufficient discharge space, which is advantageous for finishing. Pulsed direct current can promote the effect of electrochemical finishing, but the machining time is longer and the cost is raised. The average ultrasonic effect is much better than the pulsed current while the machining time needs not be prolonged by the off-time. The higher current density and higher current rating with ultrasonic assistance can avoid the difficulty of dreg discharge, thus reducing the finishing time. It is a great contribution that the ultrasonic-assistance electrochemical finishing after screw machining requires a shorter time than manual or machine polishing to make the surface of female screws smooth and bright.

江戸時代に製造された火縄銃の金属組織

The metallurgical microstructure and mechanical properties of the steel barrel of a Japanese matchlock gun fabricated in the Edo period have been investigated. The purpose of this work is to obtain modern materials-science data of the Japanese matchlock gun and to study the manufacturing technique of the steel barrel. Test pieces are cut from the center, the muzzle and the screw of the barrel. The carbon concentration is determined by chemical analysis. The metallurgical microstructure and nonmetallic inclusions of the barrel are observed using an optical microscope and a scanning electron microscope (SEM). Test pieces for measuring the mechanical properties are cut from the gun. To evaluate the hardness, Vickers hardness (Hv) is used. The stress-strain curve, tensile strength and elongation of the gun are obtained. The carbon concentration is 0.01∼0.1mass% for the center of the barrel, 0.04∼0.1 mass% for the muzzle of the barrel, 0.05∼0.5 mass% for the front sight (Saki-meate in Japanese) and 0.13∼0.3 mass% for the male screw. The distribution of nonmetallic inclusions in the center and in the muzzle of the barrel suggest that the barrel was fabricated by a manufacturing technique called Udonbari (in Japanese). The metallurgical microstructure of the specimen taken from the muzzle of the barrel in the vertical direction suggests that the barrel and a front sight were joined mechanically. Both male and female screws were made by a cutting technique. The tensile strength and elongation are 316∼366 MPa and 25.0∼31.4%, respectively.

The analysis of failure of thoracolumbar vertebral fracture patients used in the pedicle screw fixation systems.

Objective To analysis the possibilities which have caused posterior pedicle screw loosen, break and other failures found in the thoracolumbar vertebral fracture patients, and analysis the strategy.Methods This retrospectively review contained 625 patients suffered thoracolumbar vertebral fracture who was treated in our hospital and completed the follow-up period for at least 2 years.There are 401 males and 224 females, with the mean age of 32.8 years, ranged from 15 to 58 years, and 389 patients with bone graft, 236 patients without bone graft.All the 625 patients' complete X-ray records as well as patients records were analyzed.The diagnosis of failure should be supported by both patient records and X-ray image records.All these patients' operation records were reviewed to identify whether the patients have the bone grafting during the operation.Results There were totally 21 patients experiencing the pedicle screw fixation system failure, which included thoracic-lumbar conjunction region in 14 patients and lumbar region in 7 patients.The failure rate was 3.36%.The pedicle screw break was found in 15 patients, the connection rod break in 1 patient, the looseness of the system in 3 patients, and the female screw shedding in 2 patients.The failure time was 1.97 years in average.The failure rate in bone grafting patients group was 1.03%, while in the group of without bone grafting patients was 7.20%; there was a significant difference between two groups(x2=3.92,P<0.05).Conclusion There is no difference between the thoracic-lumbar conjunction region and the lumbar region.Effective bone grafting can help the system to get a good result and avoid failure.For the burst vertebral fracture patients, both posterolateral and transverse bone grafting should be performed.The systematic rehabilitation and avoidance of heavy labor postoperatively can be helpful in achieving a good result. Key words: Spinal fractures; Internal fixators; Treatment failure

Ultrasonic-aided Electrochemical Finishing of female screw using completely inserted electrode

An effective system of ultrasonic-aided electrochemical finishing using low cost design electrodes for a female screw is developed. The process can be integrated with the primary processes of traditional turning, tapping, or rolling to achieve a good surface finish for screw threads. In the experiment, ultrasonic energy is transmitted to the electrolyte to assist the dregs discharge during polishing process. Four types of design electrode are completely inserted and put through both continuous and pulse direct current. It was found that the electrode with one side plate performs better than one with both sides. An electrode with one side plate with short width of plate provides larger discharge space and produces the best polishing effect. The average effect of the ultrasonics is found to be more effective than the use of pulsed current, without sacrificing the polishing time. The ultrasonic-aided electrochemical finishing needs quite a short period of time to make the surface of the female screw smooth and bright.

Design of Completely Inserted and Feeding Electrode for Female Screw in Electrochemical Finishing

This study discusses electrochemical finishing of female screw using different types of completely inserted electrodes as well as feeding electrodes for die material. In the experiment, four types of design electrode are completely inserted and put through both continuous and pulse direct current and another four types of electrode are used with the application of continuous direct current and axial electrode feed. The controlled factors include the chemical composition and the concentration of the electrolyte, the electrolyte temperature, the flow rate of electrolyte, rotational speed of the electrode, current density, and current rating. The parameters are electrolytic time, die material, pulse period, feed rate of the electrode, and electrode geometry. For inserted electrodes, an electrode with thin plate provides more sufficient discharge space, which is advantageous for polishing. The electrode of single plate performs better than the double plate. Pulse direct current can promote the effect of electrochemical finishing, but the machining time is longer and the cost is raised. For feeding electrodes, an electrode of one side borer tip and thinner heavy section performs the best polishing effect in the current investigation. The electrochemical finishing after screw cutting just needs quite short time to make the surface of female screw smoothing and bright.

１５％ＳｉＣ粒子強化２６１８アルミニウム合金のＴｉＮコーティング溝なしタップによる加工性能

Machining processes such as drilling and tapping are necessary before MMC can be used as a machine parts. However, since MMC contains ultra-hard particles and short fibers machining is difficult due to the severe tool wear in cutting operations. Therefore in this study, an efficient machining method of the female screw which is essential for fastening machine parts is examined by subjecting the work piece material to plastic deformation and an attempt is made to tap MMC with fluteless tap that forms the female screw. Tapping tests on Al–15%SiC alloy were carried out using two types of fluteless taps HSS and TiN coated fluteless taps. The following conclusion can be drawn after examining results of the processing characteristics. The friction coefficient of the TiN coated tap is less than that of the HSS tap, due to the excellent wear resistance of the TiN coated tap processing resistance is small resulting in a 3.8 fold increase in tool life. The plastic flow evident during the formation of threads is small. As a result, with TiN coated tap, the work hardening of the thread surface is 35% lower than with HSS tap. It is evident that thread formation is efficiently performed.

Variable directional capacitor microphone comprising elastic acoustic resisting member

The present invention includes a variable directional capacitor microphone in which two capacitor elements are combined. Each of the capacitor elements includes a vibrating plate and a fixed electrode, and an acoustic resistance can be adjusted in the state that the microphone has been assembled. The variable directional capacitor microphone of this invention includes capacitor elements 10 a, 10 b. In each of the capacitor elements 10 a, 10 b, each of vibrating plate supporting members 12 a, 12 b, each of spacer rings 13 a, 13 b, each of fixed electrodes 14 a, 14 b having through holes 141 and each of pedestals 15 a, 15 b having a through hole in each center of the pedestals are assembled in this order, respectively, in each of ring-shaped cases 16 a, 16 b. Each of vibrating plates 11 a, 11 b is strained and fixed on each of vibrating plate supporting members 12 a, 12 b, respectively. The capacitor elements 10 a, 10 b are combined through a connecting ring 22 having female screw threads 221 with the pedestal 15 a, 15 b facing back-to-back. An elastic acoustic resisting member 31 is disposed between the pedestals 15 a, 15 b. The acoustic resistance of the acoustic resisting member 31 can be adjusted with the lengths of thread engagement of the pedestals 15 a, 15 b with the connecting ring 22.

Separable speaker cover box containing speaker system

A novel speaker box system for a deep bass amplification consists of a front trumpet horned speaker cover box and a rear speaker box. The rear speaker box consists of a cylindrical box and a speaker installed at one end of the cylinder. The other side of the speaker box has a hole for electrical wires to the speaker. The front trumpet horned speaker cover box consists of a cylindrical box and a trumpet. The trumpet is attached to one end of the cylindrical box. The center of the trumpet has an air port connecting the inner side of the trumpet box and the open air. The trumpet horned speaker cover box and the speaker box of this invention are assembled in one set by, including but not limited to, a male thread screw carved on the outside of the speaker box and a female thread screw inside of the trumpet box. Those boxes are assembled in one set for a hip-hop or a rap, which needs a deep bass sound. For a classical music or opera, the bass amplifying trumpet horned speaker cover box is separated from the speaker box.

空気式静圧送りねじの変動解析(O.S.14-3 伝動機構・装置(3))

The purpose of this study is to make clear analytically the fluctuation phenomenon of an aerostatic lead screw supposing to having an influence on its positioning accuracy. As the first step of its study, we succeeded measuring the fluctuation per 2π radian each screws experimentally, and considering theoretically. As the results, (1) The positioning accuracy was improved by using an air bearing effect, we call "Balancing effect". (2) It is assumed that the theoretical value of the female screw fluctuation is able to calculate by the balance of each axial loads.

2539 空気式静圧送りねじに関する研究 : ストローク 200mm ねじの製作

This study is related on the performance improving of the aerostatic lead screw. It is characterized by the followings; free from friction and wear, no trouble due to air leakage, and so forth. Therefore, an aerostatic lead screw is adopted in the precision positioning device by reason of achieving higher positioning accuracy. We designed and manufactured the aerostatic lead screw of 200mm stroke as second trial production. As a result, we succeeded to measure; maximum cumulative pitch error of every 3 pitches is 13μm, angle of male screw thread is 60°3', static stiffness toward axial direction is 3.3N/μm experimentally when a clearance between male and female screws is 17μm.