On the Extraction of Milling Tools Out of Shrink Fit Chucks

2012 ◽  
Vol 523-524 ◽  
pp. 445-450 ◽  
Author(s):  
Berend Denkena ◽  
Dennis Heinisch
Keyword(s):  
High Performance ◽  
Experimental Investigations ◽  
Process Conditions ◽  
Geometrical Parameters ◽  
Dynamic Force ◽  
Unique Type ◽  
Milling Operations ◽  
Torque Transmission ◽  
Shrink Fit ◽  
Milling Tools

Thermal shrink fit chucks are widely used in high performance machining where excellent concentricity and high torque transmission are required. It was reported that in those milling operations, severe damage of tools, workpieces, and also machine tools occurs due to an extraction of the milling tool out of the shrink fit chuck during the process. Although, theoretically the interference fit assembly should withstand certain process forces, milling tools are apparently pulled out under special process conditions. The resulting increase of the cutting depth often leads to tool overload and breakage. So far, the phenomenon of tool extraction could not be explained. This paper presents an experimental approach of the investigation of the phenomenon of axial tool extraction. Therefore, a unique type of test rig for main spindles and tool interfaces is used. Experimental investigations on dynamic force and torque combinations leading to tool extraction are described. Results show, that the holding force is not only affected by geometrical parameters of the shrink fit chuck, but also by the applied dynamic load.

scholarly journals Computational and experimental investigations of one-step conversion of poly(carbonate)s into value-added poly(aryl ether sulfone)s

2016 ◽  
Vol 113 (28) ◽  
pp. 7722-7726 ◽  
Author(s):  
Gavin O. Jones ◽  
Alexander Yuen ◽  
Rudy J. Wojtecki ◽  
James L. Hedrick ◽  
Jeannette M. García
Keyword(s):  
High Performance ◽  
Density Functional ◽  
Value Added ◽  
Single Step ◽  
Nucleophilic Attack ◽  
Experimental Investigations ◽  
Aryl Ether ◽  
One Step ◽  
Poly Carbonate

It is estimated that ∼2.7 million tons poly(carbonate)s (PCs) are produced annually worldwide. In 2008, retailers pulled products from store shelves after reports of bisphenol A (BPA) leaching from baby bottles, reusable drink bottles, and other retail products. Since PCs are not typically recycled, a need for the repurposing of the PC waste has arisen. We report the one-step synthesis of poly(aryl ether sulfone)s (PSUs) from the depolymerization of PCs and in situ polycondensation with bis(aryl fluorides) in the presence of carbonate salts. PSUs are high-performance engineering thermoplastics that are commonly used for reverse osmosis and water purification membranes, medical equipment, as well as high temperature applications. PSUs generated through this cascade approach were isolated in high purity and yield with the expected thermal properties and represent a procedure for direct conversion of one class of polymer to another in a single step. Computational investigations performed with density functional theory predict that the carbonate salt plays two important catalytic roles in this reaction: it decomposes the PCs by nucleophilic attack, and in the subsequent polyether formation process, it promotes the reaction of phenolate dimers formed in situ with the aryl fluorides present. We envision repurposing poly(BPA carbonate) for the production of value-added polymers.

Ultrapräzise Hochgeschwindigkeitsbearbeitung*/Ultra-precision high performance cutting - Part 1: Increasing the surface generation rate using tools with multiple cutting edges and high-speed spindels

2015 ◽  
Vol 105 (06) ◽  
pp. 366-370
Author(s):  
L. Schönemann ◽  
W. Preuß ◽  
O. Riemer ◽  
E. Foremny ◽  
E. Brinksmeier ◽  
...  
Keyword(s):  
High Speed ◽  
High Performance ◽  
Generation Rate ◽  
Surface Generation ◽  
Ultraprecision Machining ◽  
Single Edge ◽  
Ultra Precision ◽  
Optical Freeform Surfaces ◽  
Novel Approaches ◽  
Milling Tools

Die ultrapräzise Fräsbearbeitung ist eine flexible Möglichkeit zur Herstellung optischer Freiformflächen. Aufgrund der hohen Genauigkeitsanforderungen kommen hierbei jedoch zumeist einschneidige Werkzeuge und niedrige Spindeldrehzahlen zum Einsatz. Diese Arbeit zeigt zwei neue Ansätze zur Steigerung der Flächenleistung in der Ultrapräzisionsbearbeitung: den Einsatz thermisch verstellbarer Mehrfachwerkzeuge sowie die Verwendung ultrapräziser Hochgeschwindigkeitsspindeln in Verbindung mit neuen Methoden zur Auswuchtung.   Ultraprecision milling is a flexible process for generating optical freeform surfaces. Due to the tight tolerances of such parts, only single-edge tools and low spindle frequencies are applied. This publication presents two novel approaches to increase the surface generation rate in ultraprecision machining: the use of milling tools with multiple cutting edges that are aligned via a thermomechanical actuator and the application of high speed spindels that require novel approaches for balancing.

Model Approach for Displaying Dynamic Filament Displacement during Impregnation of Continuous Fibres Based on the Theory of Similarity – Theory and Modelling

2021 ◽  
Vol 36 (4) ◽  
pp. 423-434
Author(s):  
F. Schulte-Hubbert ◽  
D. Drummer ◽  
L. Hoffmann
Keyword(s):  
Process Parameters ◽  
Similarity Theory ◽  
Dynamic Compaction ◽  
Experimental Investigations ◽  
Process Conditions ◽  
Scaled Model ◽  
Compaction Behavior ◽  
Thermoplastic Matrix ◽  
Analytical Foundation ◽  
Reinforced Thermoplastics

Abstract The underlying process for the production of textile reinforced thermoplastics is the impregnation of dry textile reinforcements with a thermoplastic matrix. The process parameters such as temperature, time and pressure of the impregnation are mainly determined by the permeability of the reinforcement. This results from a complex interaction of hydrodynamic compaction and relaxation behavior caused by textile and process parameters. The foundation for the description and optimization of impregnation progresses is therefore the determination of the pressure-dependent permeability of fibre textiles. Previous experimental investigations have shown that the dynamic compaction behavior during the impregnation of fibre reinforcements with thermoplastics or thermosets can be successfully characterized. However, for most cases, an analytical representation has not been possible due to the complexity of the process. Although it may be possible to reproduce this behavior by numerical calculations, the results need to be confirmed by experiments. This paper lays the analytical foundation for building a scaled model system, based on the theory of similarity, to observe, measure, and evaluate the dynamic compaction behavior of textile reinforcements under controlled process conditions.

Criteria for Best Performance of Pre-Optimized Solid Dampers

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Chiara Gastaldi ◽  
Muzio M. Gola
Keyword(s):  
High Performance ◽  
Nonlinear Finite Element ◽  
Design Stage ◽  
Experimental Investigations ◽  
Early Design Stage ◽  
Real Contact ◽  
Starting Point ◽  
Definition Of ◽  
Stiffening Effect ◽  
Contact Parameters

This paper furthers recent research by these authors. The starting point is the pre-optimization of solid dampers, which ensures that all dampers bound to “misbehave” are excluded since the early design stage. The authors now enlarge the scope of their investigations to explore those damper configurations selected inside the admissible design area. The purpose of the paper is to present a set of criteria apt to select a damper configuration which not only avoids unwanted situations, but in addition guarantees high performance under different design conditions. The analysis starts with the definition of a set of requirements a high performance damper should meet. In detail, the present investigation seeks to answer the following questions: in the low excitation regime, what is the frequency shift and the stiffening effect each damper can provide? for increasing excitation levels, which damper will start slipping sooner? in the high excitation regime, which damper provides the maximum dissipation? Like pre-optimization, it does not involve nonlinear finite element calculations, and unlike existing optimization procedures, is not linked to a specific set of blades the damper may be coupled to. The numerical prediction of the blade-damper coupled dynamics is here used only for validation purposes. The approach on which this paper rests is fully numerical; however, real contact parameters are taken from extensive experimental investigations made possible by those purposely developed test rigs which are the distinctive mark of the AERMEC Lab of Politecnico di Torino.

scholarly journals Enhanced Central System of the Traversing Rod for High-Performance Rotor Spinning Machines

2017 ◽  
Vol 17 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Jan Valtera ◽  
Petr Žabka ◽  
Jaroslav Beran
Keyword(s):  
Mathematical Model ◽  
High Performance ◽  
Mechanical Energy ◽  
Optimal Number ◽  
Dynamic Force ◽  
Rectilinear Motion ◽  
Central System ◽  
Rotor Spinning ◽  
New System

Abstract The paper deals with the improvement of central traversing system on rotor spinning machines, where rectilinear motion with variable stroke is used. A new system of traversing rod with implemented set of magnetic-mechanical energy accumulators is described. Mathematical model of this system is analysed in the MSC. Software Adams/View and verified by an experimental measurement on a real-length testing rig. Analysis results prove the enhancement of devised traversing system, where the overall dynamic force is reduced considerably. At the same time, the precision of the traversing movement over the machine length is increased. This enables to increase machine operating speed while satisfying both the maximal tensile strength of the traversing rod and also output bobbin size standards. The usage of the developed mathematical model for determination of the optimal number and distribution of accumulators over the traversing rod of optional parameters is proved. The potential of the devised system for high-performance rotor spinning machines with longer traversing rod is also discussed.

scholarly journals Ultrasonic stabilization technology of geometrical parameters of elastic plates

2017 ◽  
Vol 2 (2) ◽  
pp. 14-18
Author(s):  
Андрей Балаев ◽  
Andrey Balaev ◽  
Альберт Королев ◽  
Albert Korolev ◽  
Тимур Балтаев ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Pressure Sensors ◽  
Experimental Investigations ◽  
Geometrical Parameters ◽  
Elastic Plates ◽  
High Productivity ◽  
Technological Factors ◽  
Ultrasonic Oscillations ◽  
Ultrasonic Technology ◽  
Processing Modes

The paper reports the substantiation of the stabilization technology for geometrical parameters of elastic plates in pressure sensors carried out by means of residual stresses affected by ultrasonic oscillations. For the confirmation of the efficiency of the developed ultrasonic stabilization technology in accordance with the procedure described the experimental investigations are carried out. The results of the experimental study are presented by the equation of regression and diagrams of residual stresses dependences upon technological factors. Amplitudes of ultrasonic oscillations, a static force of tool pressure and machining duration were assumed as variable technological factors. High productivity and efficiency of the ultrasonic technology for elastic plate stabilization are proved experimentally. As a result of the experiment there are defined rational values of ultrasonic processing modes for specific geometrical and physical-mechanical parameters of a plate.

Criteria for Best Performance of Pre-Optimized Solid Dampers

2018 ◽  
Author(s):  
Chiara Gastaldi ◽  
Muzio M. Gola
Keyword(s):  
High Performance ◽  
Nonlinear Finite Element ◽  
Design Stage ◽  
Experimental Investigations ◽  
Early Design Stage ◽  
Real Contact ◽  
Starting Point ◽  
Definition Of ◽  
Stiffening Effect ◽  
Contact Parameters

This paper furthers recent research by these authors. The starting point is the pre-optimization of solid dampers, which ensures that all dampers bound to misbehave are excluded since the early design stage. The authors now enlarge the scope of their investigations to explore those damper configurations selected inside the admissible design area. The purpose of the paper is to present a set of criteria apt to select a damper configuration which not only avoids unwanted situations, but in addition guarantees high performance under different design conditions. The analysis starts with the definition of a set of requirements a high performance damper should meet. In detail the present investigation seeks to answer the following questions: – in the low excitation regime, what is the frequency shift and the stiffening effect each damper can provide? – for increasing excitation levels, which damper will start slipping sooner? – in the high excitation regime, which damper provides the maximum dissipation? Like pre-optimization, it does not involve nonlinear Finite Element calculations, and unlike existing optimization procedures, is not linked to a specific set of blades the damper may be coupled to. The numerical prediction of the blade-damper coupled dynamics is here used only for validation purposes. The approach on which this paper rests is fully numerical, however real contact parameters are taken from extensive experimental investigations made possible by those purposely developed test rigs which are the distinctive mark of the AERMEC Lab of Politecnico di Torino.

Dynamics and Stability of Partial Immersion Milling Operations

1999 ◽  
Author(s):  
M. X. Zhao ◽  
B. Balachandran ◽  
M. A. Davies ◽  
J. R. Pratt
Keyword(s):  
Hopf Bifurcation ◽  
Time Variation ◽  
Periodic Motion ◽  
Contact Time ◽  
Period Doubling ◽  
Experimental Investigations ◽  
Partial Immersion ◽  
Milling Operations ◽  
Wide Range ◽  
The Stability

Abstract In this paper, numerical and experimental investigations conducted into the dynamics and stability of partial immersion milling operations are presented. A mechanics based model is used for simulations of a wide range of milling operations and instabilities that arise due to regeneration and/or impact effects are studied. Poincaré sections are used to assess the stability of motions. The studies reveal that apart from Hopf bifurcation of a periodic motion, a period-doubling bifurcation of a periodic motion may also lead to chatter in partial immersion milling operations. Issues such as tooth contact time variation and structure of stability charts are also discussed.

Process and Evaluation of High Reliability Reworkable Edge Bond Adhesives for Large Area BGA Applications

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 002018-002053
Author(s):  
Swapan Bhattacharya ◽  
Fei Xie ◽  
Daniel F. Baldwin ◽  
Han Wu ◽  
Kelley Hodge ◽  
...  
Keyword(s):  
High Performance ◽  
Printed Circuit Boards ◽  
Process Development ◽  
High Reliability ◽  
Optimum Process ◽  
Process Conditions ◽  
Harsh Environment ◽  
Mechanical Shock ◽  
Large Area ◽  
Reliability Performance

Reworkable underfills and edge bond adhesives are finding increasing utility in high reliability and harsh environment applications. The ASICs and FPGAs often used in these systems typically require designs incorporating large BGAs and ceramic BGAs. For these high reliability and harsh environment applications, these packages typically require underfill or edge bond materials to achieve the needed thermal cycle, mechanical shock and vibration reliability. Moreover, these applications often incorporate high dollar value printed circuit boards (on the order of thousands or tens of thousands of dollars per PCB) hence the need to rework these assemblies and maintain the integrity of the PCB and high dollar value BGAs. This further complicates the underfill requirements with a reworkability component. Reworkable underfills introduce a number of process issues that can result in significant variability in reliability performance. In contrast, edge bond adhesives provide a high reliability solution with substantial benefits over underfills. One interesting question for the large area BGA applications of reworkable underfills and edge bond materials is the comparison of their reliability performance. This paper presents a study of reliability comparison between two robust selected reworkable underfill and edge bond adhesive in a test vehicle including 11mm, 13mm, and 27mm large area BGAs. Process development for those large area BGA applications was also conducted on the underfill process and edge bond process to determine optimum process conditions. For underfill processing, establishing an underfill process that minimizing/eliminates underfill voids is critical. For edge bond processing, establishing an edge bond that maximizes bond area without encapsulating the solder balls is key to achieving high reliability. In addition, this paper also presents a study of new high performance reworkable edge bond materials designed to improve the reliability of large area BGAs and ceramic BGAs assemblies while maintaining good reworkablity. Four edge bond materials (commercially available) were studied and compared for a test vehicles with 12mm BGAs. The reliability testing protocol included board level thermal cycling (−40 to 125°C), mechanical drop testing (2900 G), and random vibration testing (3 G, 10 – 1000 Hz).

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