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Topic: Paste (rheology)


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In the News (Fri 19 Jul 19)

  
  SOLDER PASTE HANDLING GUIDELINES
The initial bead of solder paste should be the full length of the printable pattern on the stencil, in a diameter of approximately 1/2 inch.
If more solder paste is removed from refrigeration than is used, simply re-seal the jar or cartridge and leave it out at room temperature until it is ready to be used again.
One relatively common result of this interaction is older paste dry-out The solder paste supplier should be contacted in order to determine which stencil cleaners are safe to use with their particular products.
www.advancetech-info.com /sphg.htm   (1095 words)

  
 EMSNow - News Publishing
Analysis of paste deposits using a solder paste inspection system allows the average solder paste volume and the standard deviation across all deposits for each solder paste on test to be calculated.
Green areas highlight the point at which paste volume is closest to the nominal value, with the lowest standard deviation: that is, a close to ideal process.
Given that the Lead-free pastes are relatively new, and the technology is at the beginning of its lifecycle, this is perhaps to be expected.
www.emsnow.com /npps/story.cfm?ID=10080   (1833 words)

  
 Paste - Wikipedia, the free encyclopedia
Glue, an adhesive, which may be a paste.
Cut, copy and paste in computing, for the popular editing paradigm.
paste (Unix), also in computing, for the Unix utility tool which is used to join files horizontally.
en.wikipedia.org /wiki/Paste   (99 words)

  
 1999 Building Publications - Measurement of the Rheological Properties of Cement Paste: A New Approach.   (Site not responding. Last check: 2007-10-13)
It is known that the rheology of concrete is afkcted by the cement paste content, by contributing to the gap between the aggregates.
It is demonstrated that the distance between the plates affects the rheological parameters of cement paste.
As the mixing procedure affects the values of the rhealogical parameters of the cement paste, special precautions were taken to mix the paste under the same conditions as those experienced in the concrete.
fire.nist.gov /bfrlpubs/build99/art059.html   (199 words)

  
 Paste (rheology) - Wikipedia, the free encyclopedia
In physics, a paste is a substance that behaves as a solid until a sufficiently large load or stress is applied, at which point it flows like a fluid.
In rheoological terms a paste is an example of a Bingham plastic fluid.
Pastes typically consist of a suspension of granular material in a background fluid.
en.wikipedia.org /wiki/Paste_(rheology)   (193 words)

  
 Influence of mineral admixtures on the rheology of cement paste and concrete - Background
The main reason for this is that cement paste rheology is typically measured under conditions that are never experienced by the cement paste in concrete.
It has been established [12] that the rheological properties of cement paste change if the material is squeezed between two surfaces or aggregates as in concrete.
In this paper, cement paste rheological parameters were measured using the above method as a function of type and dosage of mineral admixture.
ciks.cbt.nist.gov /~garbocz/ccr2000/ccr2.htm   (1066 words)

  
 Lead-free thick film paste composition - Patent 5378408
The paste composition of claim 1 wherein the electrically conductive particles are flake Ag, powdered Ag or mixtures thereof.
The paste composition of claim 3 wherein the log (eta) specific viscosity is in a range from 2 at 500.degree.
The silver paste is screen printed onto either the airside or tinside of a fiat glass substrate or onto unfired enamel using a conventional screen, typically 195 mesh polyester.
www.freepatentsonline.com /5378408.html   (5519 words)

  
 Australian Society of Rheology -Meetings and Conferences
Due to the overwhelming success of the Australian Centre for Geomechanics' (ACG) First Minerals Processing and Tailings Rheology Workshop, the ACG is in the process of planning another Minerals Processing and Tailings Rheology Workshop to be held in Perth, Western Australia prior to the 2-day ACG Tailings Management and Decommissioning Seminar, December 2003.
The keynote lectures began with renowned rheology expert, David Boger, Director and Professor, Particulate Fluids Processing Centre, The University of Melbourne, presenting a brief overview of why rheology is important to the minerals industry and how this science impacts on the design and operation of a range of unit operations in the minerals industry.
The global demand for information about the importance of rheology in paste and thickened tailings operations and the overwhelming success of this workshop have resulted the in planning of another Minerals Processing and Tailings Rheology Workshop to be held in Perth, December 2003.
www.pfpc.unimelb.edu.au /asr/agcworkshop.htm   (989 words)

  
 Suspension and Paste Rheology - Course: 23 Mar and 16 Nov 2006
Suspension and Paste Rheology - Course: 23 Mar and 16 Nov 2006
This course aims to provide an understanding of the rheological characterisation of slurries and pastes, and an appreciation of the physical and chemical effects determining rheological behaviour.
Case histories on the effects of particle size distribution on suspension rheology, rheological design for suspending solids and the use of rheology as an aid to quality control and product formulation will be given.
www.bhrgroup.co.uk /confsite/rhe-suspension-prog.htm   (425 words)

  
 Article - PVC pastes: plastisols, organosols, hydrosols I - What?
Paste processes consume roughly 4-9% of the total PVC that is to say more than 10% of the flexible PVC.
Paste processes could consume roughly 4-9% of the total PVC that is to say more than 10% of the flexible PVC.
PVC pastes, liquid dispersions of PVC into liquid plasticizer(s), coexist under two complementary forms, plastisols based on plasticizer(s) only for rather thick parts and organosols containing an extra diluent, solvent or thinner to reduce their viscosity for thin films.
www.specialchem4polymers.com /resources/articles/article.aspx?id=1790   (1330 words)

  
 Minerals Engineering International - Environmental Issues: Conference Reports
The workshop was designed to demystify the complexities of rheology, enabling attendees to further understand how slurry operations and minerals processing benefit from this innovative technology.
Coghill then proceeded to explain that mineral slurry rheology is not a fixed parameter and the slurry can indeed be manipulated through variation to ore type, water quality, the environment and of course, the addition of reagents.
Rheology Solutions generously provided 10 vistometres for use at the workshop, enabling attendees to get a “hands-on” experience in measuring slurry-like substances and seeing what happens to the slurry when reagents such as salt are added.
www.min-eng.com /environmental/reps/9.html   (917 words)

  
 European Cells & Materials Journal - Theoretical and experimental approach to test the cohesion of calcium ...
The goal of the present study was to better understand which factors affect the cohesion of a calcium phosphate paste using the combination of a theoretical and experimental approach.
In the experimental approach, a new method to measure the cohesion of a non-setting calcium phosphate paste was presented and used to assess the effects of various factors on this property.
The experimental results confirmed the theoretical predictions: an increase of the liquid-to-powder ratio of the paste and of the powder particle size, as well as the addition of citrate ions and in limited cases dissolved xanthan polymer chains reduced the paste cohesion.
www.ecmjournal.org /journal/papers/vol012/vol012a03.php   (303 words)

  
 Handbook succeeds in filling in gaps
The importance of these topics, and the unfortunate lack of understanding by many mine operators, is illustrated by the chronicles of recent failures at backfilling operations in Australia and elsewhere caused by hydraulic fill piping events, bulkhead collapses and fill failures.
In particular, the authors reinforce some of the fundamentals key to the success of paste systems such as adequate fines, matching the rheology of the paste to the hydraulics of the system and maximising the use of gravity for delivery.
Such a system of capitalising risks lends itself to highlighting the cost effectiveness of paste backfill when the potential risks of surface disposal of tailings are weighed against the cost of underground disposal.
www.ferret.com.au /articles/65/0c031d65.asp   (1291 words)

  
 Industrial Seminar & Workshop Series for Surface Coatings   (Site not responding. Last check: 2007-10-13)
IainÕs background in rheology includes a PhD in the flow of molten plastics, 13 years as a university lecturer in chemical engineering, specialising in the processing of non-Newtonian fluids, and 8 years in the dairy industry in Australia and New Zealand.
Moore has considerable expertise in the field of food processing and rheology and will present his experience regarding the use of rheology in the food industry, with many references to his personal experiences.
Rheology is a tool that is generally under-utilised in the food industry, but which can offer solutions to a range of processing problems.
www.rheologysolutions.com /seminar_food.html   (2043 words)

  
 2001 Building Publications - Influence of Mineral Admixtures on the Rheology of Cement Paste and Concrete.   (Site not responding. Last check: 2007-10-13)
The conclusions reached based on cement paste tests were validated by concrete slump tests.
The cement paste rheological data were also compared using two simpler tests, mini-slump and Marsh cone.
The goal was to determine whether the simpler tests could be used to characterize the rheology of cement paste adequately.
fire.nist.gov /bfrlpubs/build01/art011.html   (218 words)

  
 Measurements for electronics assemblies
There are significant variations in paste printability and stencil performance, as well as paste working and storage life which are not clearly understood.
This project will investigate the key parameters in the stencil printing process, looking at paste printability with laser profilometry, and paste rheology as a function of the local environment.
In this project the amount of solder paste applied to the joint and the pad area is being varied.
www.npl.co.uk /materials/programmes/mmp/mfea.html   (523 words)

  
 EMSNow - News Archives   (Site not responding. Last check: 2007-10-13)
PRA is effectively a micro-fine pattern created on the squeegee side of the stencil which has been designed to significantly improve paste roll.
The PRA wave pattern assists in activating and 'conditioning' the paste to improve its rheology.
The company recognises that optimum paste condition is critical to the printing process.
www.emsnow.com /newsarchives/archivedetails.cfm?ID=4446   (191 words)

  
 PASTE Articles from AMAZINES.COM - The Article Database and EZine Publishers Database   (Site not responding. Last check: 2007-10-13)
For the past few years, in the processor field, the trend has been slowly shifting from a single high Hz CPU to multicore processors.
Intel has Xeon dual core and has managed to paste two such chips to bring out what it calls quad core, AMD still has only Opteron dual-core CPUs and is likely to release native quad-core chip next year.
Aside from using the Clipboard to collect and paste text cut or copied from multiple Office Applications, the Clipboard is handy when researching information on the internet or reading e-mails.
www.amazines.com /Paste_related.html   (1340 words)

  
 RIT CEMA - Surface Mount Technology - Already Accomplished
Topics include an in-depth look at stencils, solder paste, squeegee, process parameters, process characteristics, inspection techniques, defect identification and corrective actions.
Participants in this course are sure to acquire a sound understanding of the solder paste print process and its influence on yield.
Understand the importance and the influence of solder paste, flux, temperature, humidity, board support and machine setup.
www.rit.edu /~smt/stencilprinting.php3   (261 words)

  
 Dr.ing. Jon E. Wallevik   (Site not responding. Last check: 2007-10-13)
Rheology of cement pastes used for thermal wells (temperature effects on filler modified cement paste).
Rheological relationship between filler modified cement paste and fresh concrete, using polycarboxylate based superplasticizer (a high-range water-reducer).
[20] Hammer T. and Wallevik, J. (2005); On the Correlation Between Rheology of Paste, Mortar and Concrete; Proceedings of the Second North American Conference on the Design and Use of Self-Consolidating Concrete (SCC) and the Fourth International RILEM Symposium on Self-Compacting Concrete, Chicago, USA 2005, A Hanley Wood Publication, ISBN 0-924659-64-5.
folk.ntnu.no /jonelvar/cv.html   (1160 words)

  
 SMTA - The Surface Mount Technology Association
Paste rheology, board warp, aperture size and many other assembly features drive the need for continuous monitoring of solder deposition volume.
Current screen print equipment offers 2D and 3D paste inspection capability, but fails to archive the inspection data to permit continuous monitoring of solder volume.
Defining the Paste Deposition Process Window There are many factors that come into play when defining solder volume control limits.
www.smta.org /knowledge/proceedings_abstract.cfm?PROC_ID=772   (319 words)

  
 Rheology Courses
Rheology Courses at the University of Strathclyde, Glasgow.
Free rheology seminars at the above three locations in order for potential delegates to get a flavour of planned courses and to be able to find out more with respect to other courses.
Rheology and Texture of Cereal Foods A short course sponsored by the AACC Rheology Division CONTACT: Dr Mahesh Padmanabhan
www.ncl.ac.uk /rheology/conferences/courses.html   (773 words)

  
 NPL: Application of Electronic Interconnection Media
This is particularly testing for the application of solder pastes and adhesives where performance enhancements in terms of speed and pitch have had to be made.
Recently solder paste has been printed directly from printer cartridges conferring different printing characteristics and protecting the paste from the ambient environment.
Issues such as dispensing mechanisms, screw or positive displacement, nozzle design and dispensing pressure, and rheology were studied.
www.npl.co.uk /materials/programmes/mpm/aoeim.html   (343 words)

  
 Rheology of Cement Paste and Concrete
Much has been learned in recent years about the rheology of cement paste and how it relates to microstructure.
This paper reviews recent studies of cement paste in our laboratory in which dynamic rheological properties are used to follow the effects of cement hydration.
It appears likely that concrete rheology is controlled by rheology of its paste, although such links have not yet been directly established.
www.astm.org /JOURNALS/CEMENT/PAGES/94.htm   (221 words)

  
 Processing | ACBM
These give rise to frictional forces, which resist particle rotation and sliding, such that particles do not simply collapse to random close packing when an external load is applied, but rather compress to some new density and microstructure in equilibrium with the applied load.
ACBM has developed unique methodologies for studying the processing of polymer-cement composites which couple torque measurement during shear mixing with rheological analysis of the paste prior to hardening.
This data provides a base for quantifying paste rheology and allows the prediction of scale-up behavior.
acbm.northwestern.edu /processing.html   (441 words)

  
 BHR Group's courses in Solutions, Suspensions, Solids and Slurries - Rheology in Action
A wide range of industrial materials occur in the form of slurries, emulsions, pastes and polymer solutions and melts.
These courses cover rheological characterisation and processing and handling of a wide range of industrial materials including liquids, slurries, emulsions, pastes, polymer solutions and melts.
Our specialist information service, in conjunction with our rheology staff, offers an information retrieval service on a one-off or regular basis.
www.bhrgroup.co.uk /confsite/rheology.htm   (386 words)

  
 Industrial Coatings - Cray Valley Rheology and Surface Modifiers
Rheology Modifiers for the control of sedimentation and sag resistance.
For rheology control, Cray Valley offers the formulator a wide range of products based on a variety of chemistries:
Compared to castor wax based rheology modifiers, pure amide modifiers are considerably more tolerant of strong solvents and elevated processing temperatures, particularly those normally encountered with the use of Cowles-type high-speed dispersers.
www.crayvallac.com /indust.html   (367 words)

  
 Chepaume
The smooth, tapered aperture walls offer the best paste release characteristics available which, when combined with the surface properties of Nickel, maximize both the solder paste deposit and its release, even from the finest of stencil apertures.
The unique pattern on the NES has been developed to ensure the solder paste will roll and not skid across the stencil with the progression of the squeegee blade.
In response to the problem of applying solder paste for both surface mount connectors and finer pitch components without excess solder deposits that may cause bridging, Chepaume Industries has developed Multi Level Electroformed stencils.
www.chepaume.com /electroforming.html   (395 words)

  
 Cut Paste
For arheological properties of pastes such as toothpaste or putty, see Paste (rheology).
In computing, cut and paste is a user-interface paradigm for a means of moving text (typically plain text) or other data from a source to a destination.
The term ""cut and paste"" of course derives from the traditional practice in manuscript editing in which paragraphs were literally cut from a page with scissors and physically pasted onto another page.
www.handybackup.net /backup_terms/cut_paste.shtml   (244 words)

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