"Predicting And Minimizing Working Zone Migration On Nd-Tools Used In Aspherical Micromachining With The Erickson-Watt Approach".

1986 ◽  
Author(s):  
J. Arnold
Keyword(s):  
Working Zone

An experience of elaboration and implementation of systems of slag-forming mixtures mechanized feeding into CCM moulds

2020 ◽  
Vol 76 (10) ◽  
pp. 994-1003
Author(s):  
S. P. Eron’ko ◽  
M. Yu. Tkachev ◽  
E. V. Oshovskaya ◽  
B. I. Starodubtsev ◽  
S. V. Mechik
Keyword(s):  
Economic Effect ◽  
Three Dimensional ◽  
Movable Part ◽  
High Quality ◽  
Working Zone ◽  
Fine Material ◽  
Mixing Chamber ◽  
Field Samples ◽  
Technical Solutions ◽  
Feeding Systems

Effective application of slag-forming mixtures (SFM), being fed into continuous castingg machine (CCM) moulds, depends on their even distribution on the melt surface. Manual feeding of the SFM which is widely usedd does not provide this condition, resulting in the necessity to actualize the work to elaborate systems of SFM mechanized feedingg into moulds of various types CCM. A concept of the designing of a system of SFM feeding into CCM moulds presented with the ratte strictly correspondent to the casting speed and providing formation of an even layer of fine material of given thickness on the whoole surface of liquid steel. The proposed methods of designing of the SFM mechanized feeding systems based on three-dimensional computer simulation with the subsequent verification of the correctness of the adopted technical solutions on field samples. Informattion is presented on the design features of the adjusted facilities intended for continuous supply of finely granulated and powder mixtuures on metal mirror in moulds at the production of high-quality billets, blooms and slabs. Variants of mechanical and pneumo-mechaanical SFM supply elaborated. At the mechanical supply the fine material from the feeding hopper is moved at a adjusted distance bby a rigid horizontally located screw. At the pneumo-mechanical supply the metered doze of the granular mixture is delivered by a sshort vertical screw, the lower part of which is located in the mixing chamber attached from below to the hopper and equipped with ann ejector serving for pneumatic supply of the SFM in a stream of transporting gas. It was proposed to use flexible spiral screws in the ffuture facilities of mechanical SFM feeding. It will enable to eliminate the restrictions stipulated by the lack of free surface for locatiion of the facility in the working zone of the tundish, as well as to decrease significantly the mass of its movable part and to decreaase the necessary power of the carriage moving mechanism driver. The novelty of the proposed technical solutions is protected by thhree patents. The reduction of 10–15% in the consumption of slag-forming mixtures during the transition from manual to mechanizeed feeding confirmed. The resulting economic effect from the implementation of technical development enables to recoup the costs inncurred within 8–10 months.

scholarly journals Use of Gracile and semi-tendinosus tendons (GRAST) for the reconstruction of irreparable rotator cuff tears

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Marie Protais ◽  
Maxime Laurent-Perrot ◽  
Mickaël Artuso ◽  
M. Christian Moody ◽  
Alain Sautet ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Donor Site ◽  
Anatomical Study ◽  
Donor Site Morbidity ◽  
Rotator Cuff Tears ◽  
Subacromial Space ◽  
Greater Tuberosity ◽  
Working Zone ◽  
Superior Capsular Reconstruction

Abstract Background Irreparable rotator cuff tears are common and difficult to treat. Techniques for “filling the loss of substance” require fixation to the rotator cuff stump (tendon augmentation) or to the glenoid (superior capsular reconstruction), which are complicated by the narrow working zone of the subacromial space. The main objective of this study was to determine whether a braided graft of gracilis (GR) and semitendinosus (ST) could fill a loss of tendon substance from an irreparable rupture of the supra- and infraspinatus, by fixing the graft to the greater tuberosity and the spine of the scapula. Methods This was a cadaveric study with the use of ten specimens. The GRA and ST tendons were harvested, braided and reinforced with suture. An experimental tear of the supraspinatus (SS) and upper infraspinatus (IS) retracted at the glenoid was made. The GRAST transplant was positioned over the tear. The transplant was attached to the greater tuberosity by two anchors and then attached to the medial third of the scapular spine by trans-osseous stitching. The percentage of filling obtained was then measured and passive mobility of the shoulder was assessed. We proceeded to the same technique under arthroscopy for a 73 years old patient whom we treated for a painful shoulder with irreparable cuff tear. We inserted a GRAST graft using arthroscopy. Results The Braided-GRAST allowed a 100% filling of the loss of tendon substance. Mobility was complete in all cases. Conclusion This technique simplifies the medial fixation and restores the musculo-tendinous chain where current grafting techniques only fill a tendinous defect. The transplant could have a subacromial “spacer” effect and lower the humeral head. The donor site morbidity and the fate of the transplant in-vivo are two limits to be discussed. This anatomical study paves the way for clinical experimentation.

scholarly journals The Behaviour of Graphitized Steels in Machining Processes

2016 ◽  
Vol 879 ◽  
pp. 1600-1605
Author(s):  
H. Roelofs ◽  
N. Renaudot ◽  
D. Smolenicki ◽  
J. Boos ◽  
F. Kuster
Keyword(s):  
Interface Temperature ◽  
Case Hardening ◽  
Low Carbon ◽  
Machining Processes ◽  
Working Zone ◽  
Test Methodology ◽  
Case Hardening Steel ◽  
Graphite Inclusions ◽  
Optimum Working

Graphitized steels are claimed to perform excellent in machining processes. They therefore can be considered as environmental friendly alternatives to the widely used Pb-alloyed steels. Due to liquid metal embrittlement and in-situ lubrication Pb improves machinability in a narrow tool-chip interface temperature window corresponding to low machining speeds. Although graphite inclusions are also supposed to generate in-situ lubrication, the mechanism and the corresponding optimum working zone is not very clear. The present work applies a new test methodology (including in-situ tribology, analysis of material flow and chip formation, optimum working zone analysis) to investigate the effects of graphite inclusions on turning and drilling operations. A Pb-alloyed low carbon free-cutting steel and Pb-alloyed case hardening steel were used as reference steels.

scholarly journals On Adaptive Control for Electrical Discharge Machining Using Vibroacoustic Emission

Technologies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 96 ◽  
Author(s):  
Yury Melnik ◽  
Mikhail Kozochkin ◽  
Artur Porvatov ◽  
Anna Okunkova
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Hard Alloys ◽  
Monitoring And Control ◽  
Working Zone ◽  
Conductive Ceramics ◽  
And Control ◽  
Adequate Data

The article is related to the research of the parameters of vibroacoustic emission for development of the monitoring and adaptive control system for electrical discharge machining. The classical control system based on a response of electrical parameters does not give an adequate data in the cases of a new class of materials processing as conductive ceramics reinforced by conductive nano additives and carbon nanotubes and whiskers. The idle pulses, which are working on the destruction of the erosion products in the gap, count as working pulses. The application of the monitoring and control tools based on vibroacoustic emission gives adequate data about conditions in the working zone. The developed system is available to count only impulses involved in working on the destruction of the workpiece. The experiments were conducted on the samples of materials with a low melting point as austenitic steel and aluminum alloy, and hard alloys. The records of vibroacoustic signals were analyzed for detection of the monitoring and adaptive control criteria.

scholarly journals Computing the Safe Working Zone of a 3-RRS Parallel Manipulator

2016 ◽  
pp. 113-120 ◽  
Author(s):  
Dhruvesh Patel ◽  
Rohit Kalla ◽  
Halil Tetik ◽  
Gökhan Kiper ◽  
Sandipan Bandyopadhyay
Keyword(s):  
Parallel Manipulator ◽  
Working Zone ◽  
Safe Working Zone ◽  
Safe Working

scholarly journals FLAT ASYNCHRONOUS ELECTRIC DRIVE OF STONE MILL

2019 ◽  
Vol 14 (2) ◽  
pp. 77-82
Author(s):  
Рустам Аипов ◽  
Rustam Aipov ◽  
Рустам Галиуллин ◽  
Rustam Galiullin ◽  
Раушан Нугуманов ◽  
...  
Keyword(s):  
Asynchronous Motor ◽  
Rotation Frequency ◽  
Point Of View ◽  
Working Zone ◽  
Electric Drives ◽  
Belt Drives ◽  
Asynchronous Electric Drive ◽  
Asynchronous Motors ◽  
Longitudinal Edge ◽  
Flour Production

In modern flour production, the preservation of all vitamins and minerals in it is relevant. Minerals and vitamins are stored in flour, ground from whole grains. In the stone mills, the grain is subjected to repeated exposure to the working surfaces of the millstones, as a result of which the flour contains a large percentage of the most important components of the grain. The stone mill’s drive should provide a low rotational speed of the mills (peripheral speed up to 10 m/sec.) and the possibility of smooth control of its speed and torque without reducing the performance of the mill. From this point of view, it is promising to use in the mill’s drive, instead of asynchronous motors, rotation with additional devices (gearboxes, belt drives, V-belt drives, etc.) of flat asynchronous electric drives. The article suggests possible variants of technical solutions for stone mills with flat electric drives. It was concluded that the use of a flat asynchronous motor in the mill’s drive allows not only smoothly adjusting the frequency and torque of the millstones, but also because of the presence of edge effects, to prevent flour sticking in the millstone working zone. Compiled with the possibility of solving by analytical methods a mathematical model of mill’s drive, based on a flat electric drives, taking into account the longitudinal edge effect, the strength of viscous (internal) and dry (external) friction. The mechanical characteristics of the drive were found when moving the flat electric drives inductors and the dependencies of the change in the mill productivity on the millstone rotation frequency when grinding various grains, changing the fill factor of the grinding zone and the gap between the millstones were obtained.

Comprehensive Anatomic and Morphometric Analyses of Triangular Working Zone for Transforaminal Endoscopic Approach in Lumbar Spine: A Fresh Cadaveric Study

2020 ◽  
Vol 138 ◽  
pp. e486-e491
Author(s):  
Halil Can ◽  
Tugrul Cem Unal ◽  
Ilyas Dolas ◽  
Gucluhan Guclu ◽  
Furkan Diren ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Cadaveric Study ◽  
Endoscopic Approach ◽  
Working Zone ◽  
Morphometric Analyses

scholarly journals Influence of Exhaust System Setup on Working Zone Pollution by Dust during Sawing of Particleboards

2020 ◽  
Vol 17 (10) ◽  
pp. 3626 ◽  
Author(s):  
Bartosz Pałubicki ◽  
Luďka Hlásková ◽  
Tomasz Rogoziński
Keyword(s):  
Air Pollution ◽  
Exhaust System ◽  
High Impact ◽  
Dust Concentration ◽  
Dust Particles ◽  
Extraction System ◽  
Wood Dust ◽  
Dust Extraction ◽  
Working Zone ◽  
Machine Work

Air pollution by wood dust in furniture production sites is an important hygiene issue. The dust is created by all types of wood and wood-based material machining, and its concentration in the working zone surrounding the machining stand depends on the effectiveness of the dust exhaust system. In present research, three setups of the dust extraction system for a conventional table sawing machine are considered while machining particleboards. The results showed a high impact of the exhaust system connection setup on the dust concentration in the air surrounding the sawing machine work stand. The use of both main and auxiliary sawdust extraction connectors together ensured the highest clearness of the air, with only 0.5 mg/m3 of dust concentration. Closing the upper hood leads to a concentration five times higher, while disconnecting it results in a ten times higher dust content. The finest dust particles (<1 µm), however, are the most numerous in the case of closing the hood.

Sign in / Sign up

Export Citation Format

Share Document