■ "Combinations" Matter More Than Individual Materials
For example,
TIM alone
cannot fix things in place.
Graphite alone
cannot insulate.
Insulating film alone
cannot spread heat.
So combinations such as
TIM + graphite,
graphite + insulating film,
and metal foil + insulating material
are needed.
In other words, a processing company’s value lies not only in handling a single material, but in
combining multiple materials into a single functional component.
■ Connecting Functions That Material Manufacturers Cannot Connect Among Themselves
Graphite manufacturers.
Adhesive manufacturers.
Insulating film manufacturers.
Metal foil manufacturers.
Each knows its own materials well.
But what the customer needs is
not a single material,
but a component that can ultimately be built into the product.
In other words, OTIS can play the role of integrating the technologies of different material manufacturers into customer components.
■ Even High-Performance Materials Cannot Be Adopted If They Cannot Be Processed
Material A.
Very high thermal conductivity.
But too soft for volume production processing to be stable.
Material B.
Slightly lower thermal conductivity.
But it can be processed with high precision.
It can be applied automatically.
Volume production quality is stable.
In this case, material B may be better in the finished product.
In other words, the highest material performance = the highest volume production performance is not true.
■ Evaluate the Merits of Materials After Processing
When comparing thermal management materials,
they are evaluated only with test pieces of the material alone.
But in reality, they are
die-cut,
laminated,
given adhesive,
compressed,
and applied to the product.
In other words, the final state is different.
That is why in material evaluation, it is important to evaluate under conditions close to the actual processed and mounted state.
■ Processing Can Change Material Performance
Protective film is applied to graphite.
Insulation goes up.
But thickness increases.
An adhesive layer is added to TIM.
Applicability goes up.
But thermal resistance increases.
In other words, processing does not just preserve material performance.
While adding new performance, it changes other performance.
That is why it is necessary to look at the component performance after processing.
■ Thermal Performance Can Be Adjusted Through Shape
Even with the same material,
full surface,
long and narrow,
multi-branched,
and with holes
change how heat flows.
For example, changing the width of graphite
also changes the amount of heat it can carry.
In other words, the processed shape becomes a means of adjusting material performance within the product.
■ Avoiding Other Components with Opening Processing
Laying thermal management material over a large area makes heat spread easily.
But in reality,
connectors,
sensors,
antennas,
screws,
and electrodes
must be avoided.
So openings and notches are provided.
In other words, a processing company has the role of fitting high-performance materials to the mounting space.
■ Slits Can Change Conformability
A single sheet is hard and cannot be applied to a curved surface.
Slits are added.
It becomes partially easier to bend.
Or stress is relieved.
Such processing can change the mechanical behavior of the material.
In other words, without changing the chemical composition of the material, processing can change usage characteristics through shape.
■ Placing Only Necessary Functions with Partial Lamination
For example, a structure is made with
graphite in the center,
insulating film only around it,
and adhesive only on the perimeter.
This makes it possible to be
thin,
light,
and have only the necessary functions.
In other words, in processing thermal management materials, partial processing can deliver more value than full-surface processing in some cases.
■ Material Yield Also Affects the Cost of Thermal Management Components
High-performance graphite.
High-thermal-conductivity TIM.
High-performance insulating materials.
Such materials can be expensive.
That is why
how to arrange them,
how many to take per sheet,
and how much unnecessary material to reduce
are important.
If material yield can be improved through processing design, component costs can be lowered.
■ The More Expensive the Material, the Greater the Value of "Using It Only Where Needed"
Using high-performance material over the entire surface.
Reliable but expensive.
A composition with
high-performance TIM only where heat generation is really large
and general materials elsewhere
can also be considered.
In other words, by placing high-performance materials only where needed through processing, it may be possible to achieve both performance and cost.
■ It Can Be Processed by Hand in Prototyping but Is Difficult in Volume Production
In the laboratory, it can be
cut with scissors,
cut with a cutter,
and applied by hand.
Thermal evaluation is also good.
But volume production requires
high precision,
high speed,
continuity,
and the same state.
In other words, the role of a processing company is to turn thermal management that worked in the laboratory into a form that can be reproduced in the factory.
■ Sometimes Prototype Materials Need to Be Changed to Volume Production Materials
At the research stage, high-performance material A.
In volume production, processability is poor.
So, in consultation with the material manufacturer,
changing the liner,
slightly changing the thickness,
changing the surface treatment,
and changing the adhesive layer
improve mass producibility.
In other words, there is also value in the processing company giving feedback to material manufacturers.
■ Joint Development by Material Manufacturers and Processing Manufacturers
Material manufacturers
have high material performance,
but do not know processing methods.
Processing manufacturers
have processing experience,
but material design is outside their expertise.
If the two work together, they can create
thermal materials that are easy to process
and compositions that are easy to mass-produce.
In other words, it is important not to separate material development from processing development.
■ In Volume Production, Material Lot Differences Must Also Be Considered
Even with the same part number, there can be some variation in
hardness,
thickness,
adhesive strength,
and surface condition.
The material lot changes.
Processing conditions are kept exactly the same.
The result changes.
This can happen.
In other words, processing conditions need margin to absorb material tolerances.
■ Thermal Management Materials Can Be Affected by Temperature and Humidity
Adhesives,
foams,
and resin-based TIM
may change in hardness and tackiness with temperature.
Some materials also absorb moisture with humidity.
In other words, on the processing floor,
not only the material part number but
the processing environment is also a quality condition.
■ Storage Conditions Also Affect Processability
Materials stored refrigerated.
Materials with a specified usage time after opening.
Materials requiring humidity control.
With such functional materials, the storage state before processing is also important.
In other words, processing thermal management materials includes not only the cutting process, but
control from material receipt through storage, processing and shipment.
■ With Adhesive Materials, Look at Changes over Time
Right after processing.
Good peelability.
One week later.
Peel force changes.
After high-temperature transport.
It changes further.
This can happen.
With reel products, there is time before the customer uses them.
That is why it is necessary to consider not only the time of processing, but the state when the customer uses it.
■ Connecting Thermal Management Materials to Automated Processes with Reel Supply
Small TIM.
Insulating film.
Graphite.
Adhesive components.
These are arranged on reels at a fixed pitch.
The equipment
peels,
picks up by suction,
and applies them.
This allows thermal management components to be assembled automatically.
In other words, material processing can be extended from creating the shape to supplying it to the customer’s equipment.
■ Reel Conversion Requires Understanding Material Properties
Graphite.
TIM.
Film.
Each has a different winding set.
Peel force also differs.
Component weight also differs.
That is why
pitch,
liner,
winding diameter,
and tension
must be designed for each material.
In other words, reel supply is not just packaging.
It is the volume production interface for thermal management materials.
■ Changing to Shapes That Can Be Automated
Thermally, a long, narrow shape is ideal.
But the equipment cannot pick it up by suction.
So a tab is left on part of it.
A carrier is attached.
Recognition holes are made.
In this way,
shapes not needed in the final product are added only during the process.
In other words, a processing company can use product shapes and process shapes differently.
■ Inspection Also Changes by Material
Transparent film.
Black graphite.
Mirror-finish metal foil.
Soft TIM.
They cannot be seen with the same image inspection conditions.
That is why
lighting,
background,
and angle
are changed.
In other words, processing thermal management materials also requires inspection methods matched to the material.
■ Inspecting Thermal Performance Itself on Every Unit Is Difficult
Measuring the thermal resistance of each unit
is often not realistic in volume production.
That is why
dimensions,
thickness,
position,
air bubbles,
and appearance
are controlled.
Furthermore, processing conditions are stabilized.
In other words, rather than directly inspecting thermal performance on every unit, it is important to control the process conditions that determine thermal performance.
■ Think of Processing Quality in Terms of Functional Quality
Dimension ±0.1 mm.
This is processing quality.
But why is it needed?
So that the TIM does not come off the heat-generating surface.
In other words, thermal functional quality.
The edge position of the insulating film.
Why is it important?
To secure the required insulation distance.
In other words, safety functional quality.
In this way, it is important to understand processing numbers by linking them to product functions.
■ Failure Example: High-Performance TIM Was Adopted, but Its Shape Was Not Stable in Volume Production
TIM with high thermal conductivity was adopted.
Prototype temperatures were good.
But the material was soft, and dimensions were not stable in volume production die-cutting.
It also deformed during automatic peeling.
As a result, the application position varied.
In other words, the material performance was high, but it was not stable as component performance.
■ Failure Example: Graphite Was Processed, but Edge Insulation Was Not Considered
Graphite was adopted for heat spreading.
Thermal performance was good.
But the edges were exposed near conductive parts.
An insulation risk arose.
An additional protective film became necessary.
In other words, only graphite performance was looked at, and the structure of the finished component was not considered.
■ Failure Example: Copper Foil Had Good Thermal Performance but Added Too Much Weight
Copper foil was added over a large area to release heat laterally.
Thermal performance improved.
But weight increased.
Cost increased.
It also affected EMI design.
As a result, it was changed to partial placement.
In other words, rather than making the entire surface high-performance, making only the necessary places high-performance was more rational.
■ Failure Example: Making the Insulating Material Too Thin Made Processing Scratches a Problem
The insulating material was made thinner to reduce thermal resistance.
The withstand voltage of the material alone was not a problem.
But the effects of tiny processing scratches and metal burrs became larger.
In other words, although it was established on paper by material specifications, there was insufficient margin in volume production quality after processing.
■ Failure Example: The Customer Applied Multiple Materials Separately, and Positions Shifted
TIM.
Graphite.
Insulating film.
Applied three times in the customer’s process.
Each shifted slightly.
In the end, the required heat path and insulation position no longer matched.
If integrated on the processing manufacturer’s side, the relative positions would have been easier to control.
In other words, separating components is not necessarily the simplest approach.
■ The Researcher's Perspective: Think of Thermal Management Materials in Terms of "Heat Paths," Not "Thermal Conductivity"
Thermal conductivity of 5 W/m·K.
10 W/m·K.
Such material comparisons are important.
But in the finished product,
at what thickness,
over what area,
through which interfaces,
and where heat is released to
determine performance.
In other words, material properties are one element of the heat path.
Processing gives that heat path an actual shape.
■ The Shop-Floor Perspective: Do Not Decide Processability Just by Looking at the Material
Hearing only the material name.
Immediately answering
“We can process it.”
But one should really look at
thickness,
shape,
dimensions,
quantity,
adhesive composition,
and supply format.
Even with the same material, difficulty changes greatly depending on conditions.
In other words, in processing thermal management materials, it is necessary to judge by material × shape × volume production conditions.
■ What to Ask the Customer
In consultations about processing thermal management materials, information such as
what is to be cooled,
where heat is to be released,
whether insulation is needed,
what the operating temperature is,
what the application method is,
whether it will be automated,
and what quantity is needed
is important.
In other words, beyond the processing drawing, the more one knows about how it is used, the better the processing proposals that can be made.
■ The Value of Being Consulted Before Materials Are Specified
The customer consults at the stage of
“We want to lower the temperature of this component.”
The material has not been decided yet.
At this point,
working with material manufacturers,
candidates such as
TIM,
graphite,
and metal foil
are proposed.
And they are evaluated including processability.
In other words, even though OTIS does not sell materials, it can connect material selection and processing design.
■ OTIS's Perspective: Handling Thermal Management Materials and Making Thermal Management Components Are Different
“We can process TIM.”
“We can process graphite.”
These are necessary capabilities.
But that alone stops at describing a material processing company.
What OTIS should aim for is to think about
which material,
in which shape,
combined with what,
and supplied how, can be used in the customer’s process.
In other words, it is to progress from a company that processes thermal management materials to a company that establishes thermal management components.
■ Not Being a Material Manufacturer Can Be OTIS's Strength
If one has its own materials, one wants to sell those materials.
OTIS is not a specific thermal material manufacturer.
That is why
it can choose materials according to the application,
combine multiple manufacturers,
and combine thermally conductive materials with insulating materials.
In other words, precisely because it is a neutral processing company, it can think in terms of customer challenges rather than starting from materials.
■ Collaboration with Material Manufacturers Increases OTIS's Value
OTIS does not need to have everything on its own.
Material manufacturers have material development capabilities.
Cooling equipment manufacturers have cooling technology.
Customers have product design capabilities.
OTIS takes on
processing,
lamination,
supply formats,
and volume production stabilization.
In other words, there is value in the position that connects each company’s expertise.
■ Do Not Let Material Performance Stop at "the Last 1 mm"
A high-performance material has been completed.
But if
it cannot be applied,
cannot be formed,
or cannot be mass-produced,
it does not get into the customer’s product.
Between the material manufacturer’s performance and the customer’s product lies
the last small processing area.
Establishing this.
In other words, what OTIS calls “the last 1 mm of heat” is exactly this area.
■ What OTIS Can Do
At OTIS, by combining
● TIM processing
● Graphite processing
● Copper foil processing
● Aluminum foil processing
● Processing of insulating thermally conductive materials
● Insulating film processing
● Thermal insulation material processing
● Foam processing
● Adhesive processing
● Seal material processing
● High-precision die-cutting
● Microfabrication
● Thin-film processing
● Opening processing
● Slit processing
● Half-cutting
● High-precision lamination
● Partial lamination
● Lamination of dissimilar materials
● Carrier design
● Reel-to-reel processing
● Supply formats for automatic application
● Image inspection
● Process design from prototyping to volume production
we can turn thermal management materials into functional components usable in customer processes.
■ Outside OTIS's Expertise
OTIS is not a company that specializes in
● Formulation development of TIM materials themselves
● Manufacturing graphite raw materials themselves
● Refining and rolling metal foil itself
● Designing semiconductor chips themselves
● Designing cooling equipment itself
● Dedicated CFD analysis
As needed, we work with material manufacturers, cooling equipment manufacturers, analysis companies and customers’ design departments.
What OTIS takes on is the area of turning high-performance thermal management materials into forms that can actually be used in volume production processes.
■ Summary: Thermal Management Materials Only Work Inside Products Once They Are Processed
TIM.
Graphite.
Copper foil.
Insulating thermally conductive materials.
Thermal insulation materials.
All are high-performance materials.
But materials alone do not make a product.
Shape is needed.
Position is needed.
Lamination is needed.
Adhesion is needed.
Insulation is needed.
A supply format is needed.
Volume production reproducibility is needed.
In other words, between material performance and product performance, there is a process called processing.
Searching for materials with high thermal conductivity is important.
But what really matters is
at what thickness the material is used,
what shape it is made into,
where it is placed,
what it is combined with,
and whether the same state can be made in volume production.
Thermal management is not complete at the time high-performance materials are purchased.
Processing.
Laminating.
Making it applicable.
Inspecting.
Converting to reels.
Loading into the customer’s equipment.
Only after going through all of this does material performance become product performance.
That is why what OTIS should take on is not “cutting TIM”
nor “cutting graphite.”
It is what lies beyond that: turning thermal management materials into volume production components that can actually be used.
Material manufacturers create thermal performance.
Customers design products.
In between,
shape,
interface,
lamination,
supply format,
and volume production process
are established.
That is the role of thermal management material processing at OTIS.
Column Supervisor: Koji Kakumoto (President, OTIS Co., Ltd.)
After studying abroad and working in planning and development at a trading company, he joined OTIS Co., Ltd. in 2011. While primarily working in the Corporate Planning Department, he has also served concurrently in manufacturing and technical divisions, and since 2018 has served as President, working to drive business growth and strengthen the organization.
This article is a general technical explanation intended for educational purposes and does not refer to any specific company, product, or technology.
