Carbon Fiber Composites Manufacturing Plant, Detailed Project Report, Profile, Business Plan, Industry Trends, Market Research, Survey, Manufacturing Process, Machinery, Raw Materials, Feasibility Study, Investment Opportunities, Cost and Revenue, Plant Economics, Production Schedule, Working Capital Requirement, Plant Layout, Process Flow Sheet, Cost of Project, Projected Balance Sheets, Profitability Ratios, Break Even Analysis
Carbon fibre is an important and strategic raw material for the fabrication of advanced composite materials. Carbon fibre polymer matrix composites are being extensively used as light weight structural materials in a large number of applications. In India the use of carbon fibre composites has a history of nearly two decades. The composites technology has reach a mature level and is comparable to the best in the world.
See more
https://goo.gl/1w7RRj
https://goo.gl/aqcTRC
Contact us:
Niir Project Consultancy Services
Email: npcs.ei@gmail.com , info@entrepreneurindia.co
Tel: +91-11-23843955, 23845654, 23845886, 8800733955
Mobile: +91-9811043595
Fax: +91-11-23845886
Website: http://www.niir.org , http://www.entrepreneurindia.co
Tags
Advanced Composites Materials and their Manufacture Technology, Aerospace growth climbs with carbon fiber, Applications of Carbon Fiber - Composites/Plastics, Best small and cottage scale industries, Business consultancy, Business consultant, Business guidance, Business guidance to clients, Business Plan for a Startup Business, Business start-up, Carbon Fiber and Carbon Fiber Composites, Carbon Fiber Based Small Scale Industries Projects, Carbon Fiber Composite Based Profitable Projects, Project consultant, Project for startups, Project identification and selection, Project profile on Carbon Fiber Composite plant, Project report on Carbon Fiber Composite industries, Project Report on Carbon Fiber Composite plant, Properties of carbon fibre, Properties of Carbon Fibre Composite Materials, Setting up and opening your Carbon Fiber Composite Business, Small Scale Carbon Fiber Composite Manufacturing Projects, Small scale Carbon Fiber Composite production line, Small scale Commercial Carbon Fiber Composite making, Small Start-up Business Project, Start up India, Stand up India, Starting a Carbon Fiber Composite Manufacturing Business, Startup, Start-up Business Plan for Carbon Fiber Composite plant, Startup ideas, Startup Project, Startup Project for Carbon Fiber Composite plant, Startup project plan, Techno-Economic feasibility study on Carbon Fiber Composite plant, What is carbon fiber?, Carbon Fiber Composite Business, Carbon Fiber Composite Manufacturing, Carbon Fiber Composite Manufacturing Industry in India, Carbon Fiber Composite Manufacturing Projects, Carbon Fiber Composite Materials, Carbon Fiber Composite Making Small Business Manufacturing, Carbon Fiber Manufacturers in India
PRESSURIZED FLUIDIZED BED COMBUSTION BOILERKRUNAL RAVAL
In PFBC, the combustor and hot gas cyclones are all enclosed in a pressure vessel. Both coal and sorbent have to be fed across the pressure boundary, and
similar provision for ash removal is necessary. For hard coal applications, the coal and limestone can be crushed together, and then fed as a paste, with 25% water. As with atmospheric FBC (CFBC or BFBC), the combustion temperature between 800-900°C has the advantage that NOx formation is less. SO2
emissions can be reduced by the injection of a sorbent, and its subsequent removal with the ash.
This presentation includes all the information regarding polymer batteries, lithium polymer batteries. Including animations and transitions this PowerPoint presentation is enough for you to understand all about Polymer batteries and cells.
Bearings support moving parts, such as shafts and spindles, of a machine or mechanism.
Bearings may be classed as
(i) Rolling contact (Ball and roller) bearings.
(ii) Plain bearings.
The measurement of the physical properties (density, viscosity, surface tension, thermal conductivity, etc) is of great importance to the research industry and for the physical, chemical and biomedical applications. The thermal conductivity is a measurement of the material’s ability to conduct heat. The transient hot wire method is a suitable method to measure the thermal conductivity due to its very cheap cost of construction, accuracy and because it is a fast method of measurement. The implementation requires accurate temperature sensing, automatic control, data acquisition and data analysis. The basic procedure consists of measuring the temporal temperature rise in a thermoresistance (thin wire) immersed in the solution by applying an electrical current in the wire. Therefore, the wire works as a heat source and a temperature sensor. The time of measurement is very short and therefore the convection effect could be minimized. Then, the heat transfer to the infinite medium is due only to the conduction transfer effect. The thermal conductivity can be determined from the slope of the curve ΔT versus ln(t) due to the linear relation between ΔT and ln(t).
Carbon Fiber Composites Manufacturing Plant, Detailed Project Report, Profile, Business Plan, Industry Trends, Market Research, Survey, Manufacturing Process, Machinery, Raw Materials, Feasibility Study, Investment Opportunities, Cost and Revenue, Plant Economics, Production Schedule, Working Capital Requirement, Plant Layout, Process Flow Sheet, Cost of Project, Projected Balance Sheets, Profitability Ratios, Break Even Analysis
Carbon fibre is an important and strategic raw material for the fabrication of advanced composite materials. Carbon fibre polymer matrix composites are being extensively used as light weight structural materials in a large number of applications. In India the use of carbon fibre composites has a history of nearly two decades. The composites technology has reach a mature level and is comparable to the best in the world.
See more
https://goo.gl/1w7RRj
https://goo.gl/aqcTRC
Contact us:
Niir Project Consultancy Services
Email: npcs.ei@gmail.com , info@entrepreneurindia.co
Tel: +91-11-23843955, 23845654, 23845886, 8800733955
Mobile: +91-9811043595
Fax: +91-11-23845886
Website: http://www.niir.org , http://www.entrepreneurindia.co
Tags
Advanced Composites Materials and their Manufacture Technology, Aerospace growth climbs with carbon fiber, Applications of Carbon Fiber - Composites/Plastics, Best small and cottage scale industries, Business consultancy, Business consultant, Business guidance, Business guidance to clients, Business Plan for a Startup Business, Business start-up, Carbon Fiber and Carbon Fiber Composites, Carbon Fiber Based Small Scale Industries Projects, Carbon Fiber Composite Based Profitable Projects, Project consultant, Project for startups, Project identification and selection, Project profile on Carbon Fiber Composite plant, Project report on Carbon Fiber Composite industries, Project Report on Carbon Fiber Composite plant, Properties of carbon fibre, Properties of Carbon Fibre Composite Materials, Setting up and opening your Carbon Fiber Composite Business, Small Scale Carbon Fiber Composite Manufacturing Projects, Small scale Carbon Fiber Composite production line, Small scale Commercial Carbon Fiber Composite making, Small Start-up Business Project, Start up India, Stand up India, Starting a Carbon Fiber Composite Manufacturing Business, Startup, Start-up Business Plan for Carbon Fiber Composite plant, Startup ideas, Startup Project, Startup Project for Carbon Fiber Composite plant, Startup project plan, Techno-Economic feasibility study on Carbon Fiber Composite plant, What is carbon fiber?, Carbon Fiber Composite Business, Carbon Fiber Composite Manufacturing, Carbon Fiber Composite Manufacturing Industry in India, Carbon Fiber Composite Manufacturing Projects, Carbon Fiber Composite Materials, Carbon Fiber Composite Making Small Business Manufacturing, Carbon Fiber Manufacturers in India
PRESSURIZED FLUIDIZED BED COMBUSTION BOILERKRUNAL RAVAL
In PFBC, the combustor and hot gas cyclones are all enclosed in a pressure vessel. Both coal and sorbent have to be fed across the pressure boundary, and
similar provision for ash removal is necessary. For hard coal applications, the coal and limestone can be crushed together, and then fed as a paste, with 25% water. As with atmospheric FBC (CFBC or BFBC), the combustion temperature between 800-900°C has the advantage that NOx formation is less. SO2
emissions can be reduced by the injection of a sorbent, and its subsequent removal with the ash.
This presentation includes all the information regarding polymer batteries, lithium polymer batteries. Including animations and transitions this PowerPoint presentation is enough for you to understand all about Polymer batteries and cells.
Bearings support moving parts, such as shafts and spindles, of a machine or mechanism.
Bearings may be classed as
(i) Rolling contact (Ball and roller) bearings.
(ii) Plain bearings.
The measurement of the physical properties (density, viscosity, surface tension, thermal conductivity, etc) is of great importance to the research industry and for the physical, chemical and biomedical applications. The thermal conductivity is a measurement of the material’s ability to conduct heat. The transient hot wire method is a suitable method to measure the thermal conductivity due to its very cheap cost of construction, accuracy and because it is a fast method of measurement. The implementation requires accurate temperature sensing, automatic control, data acquisition and data analysis. The basic procedure consists of measuring the temporal temperature rise in a thermoresistance (thin wire) immersed in the solution by applying an electrical current in the wire. Therefore, the wire works as a heat source and a temperature sensor. The time of measurement is very short and therefore the convection effect could be minimized. Then, the heat transfer to the infinite medium is due only to the conduction transfer effect. The thermal conductivity can be determined from the slope of the curve ΔT versus ln(t) due to the linear relation between ΔT and ln(t).
New Mexico State University 1
New Mexico State University
Mechanical & Aerospace Engineering Department
Experimental Methods II
ME 445
LAB Exercise-4
TIME FOR BRIDGEWIRE BREAK
4.1 Objective
To apply the principles of heat transfer to estimate the break time of a resistive wire through
which a constant electric current is flowing.
Through this experiment, students will theoretically estimate the time using energy
balance equations.
Apply linear regression to fit manufacturer’s data with the model to deduce unknown
heat transfer parameters.
Predictions will be verified or contradicted by experimental measurement.
4.2 Theoretical Background
The physical representation of the problem is shown in the following figure:
Figure 4.0.1: Physical representation of the wire
A wire of length L and diameter D is considered. Due to the passage of electric current through
the wire, heat is generated internally. If radiation and convective heat loss are presumed as the
principal heat loss mechanisms, the energy balance for this problem, based on lumped mass for
the wire and infinite length, can be written:
Rate of change of Internal Energy (Qstored)
= Rate of Internal Energy Generation (Qgenerated) – Rate of Heat Loss (Qloss)
In the above equation, note that the heat input is not considered since no heat is being supplied
to the wire from its boundaries.
Symbolically, we can write the energy equation as:
TThATTAi
dt
dT
mc
wireswires
442
(4.1)
New Mexico State University 2
where,
m = mass of the wire = density of the wire * volume of the wire = ρV
Twire = Surface temperature of the wire
i = Current
R = Resistance of the wire
σ = Stefan-Boltzmann constant = 5.67 X 10
8
W/m
-2
K
-4
c = Specific heat capacity of the wire material
ε = Emissivity of the wire
As = Surface area of the wire
For present purposes the assumption is made that convection around the horizontal wire is fully
developed. The quantities m, c, I, , σ, As and Ts are presumed known. However, uncertainty
exists in the emissivity of the wire because of oxidized state is not precisely known, and the
convection coefficient is known to vary somewhat with size, and mean temperature across the
thermal boundary layer.
For the case of the wire which is to be used in this experiment, the manufacturer has provided
temperature versus current data for steady state. Hence, by using a multi-variable linear
regression, it is possible to use this data along with the steady state energy equation, to obtain
estimates for h and ε. However, when such an approach is taken, it is found that the value of ε
exceeds unity, an impossible condition. In order to resolv.
Engineering Research Publication
Best International Journals, High Impact Journals,
International Journal of Engineering & Technical Research
ISSN : 2321-0869 (O) 2454-4698 (P)
www.erpublication.org
Results of a recent survey of the top 40 domestic bare printed circuit board manufacturers. The survey evaluated the PCB fabricators on the following quality system certifications: UL, ITAR, C 7000, AS9100 and TS16949.
PCBs are electronic real estate. Establishing the foundation for assembly, there is a direct correlation between the reliability of a final electronic product and the bare printed circuit board. There is much to knowing what it takes as both a buyer and a producer of of PCBs to ensure high-reliability PCB performance.
FR-4 PCBs for LED Applications: Testing Performance of PTH and Copper Pour In...Domestic PCB Fabrication
FR-4 Circuit Boards: Testing the performance of PTH and Copper Pour instead of Metal Core PCBs in LED Applications. From the June issue of SMT Magazine.
SEC uses PTFE for our customer's Radio Frequency Microwave High Bandwidth applications. PTFE hybrids utilize Teflon in the dielectric material of the printed circuit board. Often synthesized with other high speed materials, our PTFE hybrid boards for RFMW incorporate the use of ceramic and other high-speed resin systems.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
GridMate - End to end testing is a critical piece to ensure quality and avoid...ThomasParaiso2
End to end testing is a critical piece to ensure quality and avoid regressions. In this session, we share our journey building an E2E testing pipeline for GridMate components (LWC and Aura) using Cypress, JSForce, FakerJS…
SAP Sapphire 2024 - ASUG301 building better apps with SAP Fiori.pdfPeter Spielvogel
Building better applications for business users with SAP Fiori.
• What is SAP Fiori and why it matters to you
• How a better user experience drives measurable business benefits
• How to get started with SAP Fiori today
• How SAP Fiori elements accelerates application development
• How SAP Build Code includes SAP Fiori tools and other generative artificial intelligence capabilities
• How SAP Fiori paves the way for using AI in SAP apps
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
1. Thermal Interface Material Basics for Electronic Engineers
Clemens J.M. Lasance
Philips Research Laboratories, Emeritus
Eindhoven, the Netherlands
Basics of Heat Transfer
To understand the heat transfer properties of thermal interface materials (TIMs) we need to understand
the meaning of thermal conduction, convection and resistance.
Conduction
The notion of thermal conduction is not very old. Biot (1804) and Fourier (1822) were the first to
quantitatively study the heat flow through a piece of solid material. Fourier observed that the heat flow
q was proportional to the temperature difference ΔT over the test piece, proportional to the cross
sectional area A of the bar, and inversely proportional to the length or thickness ℓ., known as Fourier’s
law:
A
q k T (1)
The proportionality constant k is called the thermal conductivity in W/mK. It is a material property and a
measure for the ability of a material to conduct heat. The range for engineering materials is from air
(0.03W/mK), via plastics (0.2 W/mK), glass (1 W/mK), aluminium (200 W/mK) to copper (400 W/mK).
Typical TIM values cover the range 0.4-4 W/mK.
Convection
The heat generated in an electronic device is usually transported by conduction to a heat sink or an area
where the heat is transferred to a fluid which is called convection. The fluid can be a gas such as air, or a
‘real’ fluid such as water. As a result, the convection heat is proportional to the area A and the
temperature difference between the wall and the main stream flow:
q hA T (2)
This equation is commonly known as “Newton’s Cooling Law”; however, it should be realized that it is
neither a law nor was it derived by Newton. In this equation, the proportionality coefficient h is called
the heat transfer coefficient in W/m2 K. As a rule-of-thumb, take for natural convection h=10 W/m2 K and
for fan-driven forced convection h=50 W/m2 K.
Resistance
The last term to discuss shortly is the thermal resistance. In a DC electrical circuit, Ohm’s law describes
the relations between the voltages and the currents. It states that a voltage difference over a resistor
causes an electrical current, which is proportional to the voltage difference: ΔV = I * R.
In steady state heat transfer, a temperature difference causes a heat flow which is proportional to the
temperature difference as is seen in equations (1,2). Both equations can be written in the form ΔT = q *
Rth, with Rth the thermal resistance (also commonly noted as R when there is no chance for misreading it
as an electrical resistance). This is analogous to Ohm’s law. In both the electrical and the thermal case
we observe that a driving force exists (either voltage difference or temperature difference), which
causes a flow (of current, or of heat) over a resistor.
2. In general, we can write the following equation for the thermal resistance in K/W:
T
R
q
The thermal resistance for conduction is:
R
kA
The thermal resistance for convection is:
1
R
hA
The thermal resistance per unit area is equal to the ratio between thickness t and thermal conductivity
k and is often used to allow for a direct comparison of the heat transfer performance of commercially
available TIMs.
t
k
The Role of TIMs in Thermal Management
Heat dissipation of semiconductor packages has become one of the limiting factors in miniaturization.
The thermal budget consists of three parts: 1) the thermal resistance of the package itself, 2) the
convective heat transfer to the outside world (to be improved by better heat sinks, higher air velocities
and/or liquid cooling), and 3) the thermal interface resistance that is defined as the sum of the thermal
resistance of the interface material plus both contact resistances.
Figure 1 Sketch of interface between two materials
Figure 1 shows a TIM between two materials, and it is clear that the effective thermal resistance consists
of the TIM plus two contact resistances. The effective material thickness is called the bond line thickness
(BLT). The problem in a nutshell is that in high-performance applications the interface thermal
resistance can easily account for 80% of the allowed total resistance. Hence, to enable an optimal choice
the thermal performance of TIMs should be known with certain accuracy. The main problem is the often
3. unknown contact resistance. Measurements are in fact the only choice because no theory exists that
predicts the value with the required accuracy despite serious progress in the science of contact
resistance.
Problems Related to TIM Specifications
Ref [1, 2] discusses the main problem with TIM characterization: the often significant difference
between standard tests performed by TIM manufacturers and real-life tests. It is instructive to
summarize the parameters that are application-specific and may influence the thermal behaviour of the
TIM in the final product.
In factory assembly applications, the inability to measure the thickness and actual TIM material
quantity applied with materials such as thermal greases,
Flatness and surface conditions of both heat sink and component,
Pressure applied. The current ASTM D5470-01 standard prescribes a pressure of 3 MPa, far above
what is used in practice (0.1 MPa) (in the next revision the standard will permit for lower pressure
testing),
Clip clamping force or screw torque,
Clip installation,
Time-dependent phenomena, e.g. reduction in clamping force, warpage, ageing of TIM, pump-out of
silicones or other fluids or carrier constituents,
Non-uniform surface heating,
Thermocouple placement. The best but also most difficult method is to measure the case
temperature of the package at the hottest spot,
Presence of manufacturing machining oils, solvents, washing agents, plastic injection molding
release agents, or other contaminants present on volume-manufactured components,
Problems increase with higher thermal conductivity (the future direction), because the influence of
the contact resistances becomes larger.
The conclusion is that it is very difficult or even impossible to reproduce operational contact resistances
in a standardized test method, for the simple reason that the vendor cannot possibly know what the
application will be. However, the conclusion should not be that henceforth the standard test should not
be performed. After all, the vendors are responsible for the characterization of their materials, which
should include information of some reproducible contact resistance. It is the responsibility of the user to
address the application-specific contact resistance issue.
Reliable vendor data should be interpreted as the minimum value a customer can possibly acquire,
given a certain pressure.
In a paper from 2005, Maguire et al. [3] did a series of tests with a high-power amplifier on an extruded
heat sink and demonstrated clearly the huge differences between vendor data and field data. Greases,
gap pads, PCMs and some homemade compounds were compared. The vendor data and the field tests
showed differences of a factor of two. Even the ranking was different. In all cases, the vendor data
underestimated the real-life interface resistance.
4. Thermal Impedance???
It is important that all people involved use the same terminology to define the performance of TIMs.
The problem is that part of the people (mostly vendors) uses the word 'thermal impedance' as
shorthand for ‘thermal resistance per unit area’. This violates the electrothermal analogy commonly in
use because of two reasons. First, in the electrical world ‘electrical resistance’ and ‘electrical impedance’
have the same unit, namely Ohm. Consequently, 'thermal impedance’ should have the dimension K/W,
not K m2/W. Second, ‘electrical impedance’ is a time-dependent quantity. In limiting cases, for frequency
zero or large enough times approaching steady state, the impedance becomes equal to the resistance.
Sticking to the current definition of ‘thermal impedance’ will cause a lot of confusion in the future,
because the use of dynamic test methods is the obvious choice for application-specific tests, one output
of which is thermal impedance. When quoting the performance of a TIM per area, we propose to use ‘R-
value’ (universally accepted in the building field), ‘thermal resistance per unit area’ or simply ’unit
thermal resistance'.
Some remarks on the standard test method
The ASTM D-5470 test method is a standard method to measure thermal resistance and bulk
conductivity for TIMs such as pads, tapes, greases and phase change materials. The sample is placed
between a hot meter bar and a cold meter bar and a steady state of heat flux is established. The ASTM
test defines thermal resistance per unit area, , to include the thermal resistance of the material
( material) plus the interfacial contact resistance of the TIM to the substrates ( interface);
total = material + interface (3)
material is bulk property and is equal to:
material = t/kbulk (4)
Where t is the thickness of the sample, and kbulk is the material bulk conductivity. Combining equations 3
and 4:
total = interface + t/kbulk (5)
The ASTM method measures total as a function of the thickness of the TIM. If the plot is linear, the
slope of the line is proportional to 1/kbulk, and the intercept is a measure of interface.
5. Conclusions
In practice the effective thermal resistance is a function of both the chosen TIM, determined by its
thickness and thermal conductivity, and the contact resistances that are usually not known.
It is the responsibility of the designer to estimate this value and judge the relative magnitude of the
TIM and contact resistance contributions.
References
[1] Lasance C. "The urgent need for widely accepted test methods for thermal interface materials", Proc.
SEMITHERM XIX, March 2003, San Jose, pp.123-128.
[2] Lasance C., Murray C., Saums D., Rencz M., Challenges in Thermal Interface Material Testing Proc.
SEMITHERM XXII, March 2006, San Jose
[3] Maguire L, Behnia M., Morrison G., Systematic Evaluation of Thermal Interface Materials - Case Study in
High Power Amplifier Design, Microelectronics Reliability vol.45, pp.711-725, 2005