■ What Is Lamination Misalignment?
Lamination misalignment means that a component is applied shifted from its designed position.
For example,
● Positional misalignment of heat dissipation sheets
● Application misalignment of graphite sheets
● Misalignment of insulating films
● Misalignment of adhesive materials
● Misalignment of EMI materials
● Misalignment of waterproof tapes
● Misalignment between laminated components, and so on.
At first glance, it may look like a slight misalignment.
In thermal management, however, this slight misalignment becomes a major problem.
■ If It Is Off the Heat Source, It Will Not Cool
Heat dissipation materials must be placed in the correct position relative to heat-generating components.
Off the center of the heat-generating component.
Off the hot spot.
Off the contact area with the cooling component.
Then the escape route for heat weakens.
In other words, lamination misalignment causes the problem of being off the heat path.
Thermal management components are meaningless just by being there.
They function only when they correctly connect the place where heat is generated and the destination where heat is released.
■ The Area Becomes Insufficient
With heat dissipation sheets and TIM, contact area is important.
When the application position shifts, the overlapping area with the heat-generating component decreases.
Then the area through which heat flows also decreases.
When the area through which heat flows decreases, thermal resistance increases.
In other words, lamination misalignment creates insufficient contact area.
As a result, even if the material’s thermal conductivity is high, actual heat dissipation performance decreases.
■ When the Edges Lift, Air Layers Form
Lamination misalignment can cause components to ride up on steps or their edges to lift.
Air layers form in the lifted parts.
Air conducts heat poorly.
In other words, lamination misalignment also
causes air layers.
This increases thermal resistance and leads to localized temperature rises.
■ Laminate Misalignment Breaks Combined Functions
Thermal management components are often not single materials but laminated structures of multiple materials.
For example,
● Graphite + insulating film
● Metal foil + adhesive material
● Heat dissipation sheet + protective film
● EMI material + insulating layer
● Waterproofing material + adhesive material, and so on.
At this point, if each layer is misaligned, the combined functions break down.
Heat flows, but it cannot insulate.
It waterproofs, but heat does not escape.
It counters noise, but the edges are exposed.
In other words, laminate misalignment can break not only heat but multiple functions at the same time.
■ Misalignment of Insulating Layers Is Dangerous
Thermal management components are sometimes combined with insulating layers.
For example, graphite and metal foil may be conductive.
That is why they need to be covered with insulating film.
However, if the insulating film shifts, the conductive material is exposed.
As a result, it may lead to
● Short circuits
● Electrical leakage
● Noise paths
● Reduced safety
In other words, lamination misalignment of thermal management components
also leads to electrical risks.
■ Misalignment of Waterproof Lines Leads to Water Entry
With waterproof tapes and sealants, the application position is extremely important.
When the waterproof line shifts, gaps form.
The edges lift.
Compression bonding becomes insufficient.
As a result, water may get in.
In other words, lamination misalignment also affects waterproofing.
When thermal management components also serve a waterproofing function,
both thermal performance and waterproofing performance are broken by misalignment.
■ Misalignment of Noise Countermeasure Materials Is Also a Problem
EMI materials and shielding materials must also be placed in the correct position.
If they shift,
● The shielding range becomes insufficient
● The ground connection becomes unstable
● Noise paths change
● Conductive materials approach unnecessary places
In other words, with heat × noise countermeasure components, application position accuracy is extremely important.
■ Lamination Misalignment in AI Servers
In AI servers, GPUs, HBM, power supply components, and high-speed communication components are arranged at high density.
The gaps between components are small, and thermal management materials also become complex.
In such an environment, slight lamination misalignment may lead to
● Hot spots
● Insufficient cooling
● Insulation defects
● EMI defects
● Assembly defects
In other words, in AI servers,
the higher the density, the more important lamination accuracy becomes.
■ Lamination Misalignment in EVs and ESS
In EVs and ESS, battery cells, cooling plates, insulating materials, thermal insulation materials, and components around busbars are combined.
If lamination misalignment occurs here, it can lead to
● Cell temperature differences
● Insufficient insulation
● Defects in thermal runaway countermeasures
● Waterproofing defects
● Reduced vibration durability
In EVs and ESS, safety and long-term reliability are important.
That is why lamination misalignment is not just a cosmetic defect,
but can become a problem related to safety.
■ Lamination Misalignment in Smartphones and Wearables
In smartphones and wearable devices, components are extremely small and thin.
That is why even slight misalignment has a large impact.
For example, problems arise such as
● Heat dissipation sheets coming off the heat source
● Graphite not connecting to the enclosure
● Waterproof tape coming off the seal line
● Adhesive material squeezing out
● Insulating film shifting
Especially in wearable devices, because they are close to the human body, localized thermal unevenness can lead to discomfort.
■ Why Does Lamination Misalignment Occur?
There are various causes of lamination misalignment.
● Material stretching
● Material warping
● How the release liner peels
● Static electricity
● Positional accuracy of automated machines
● Unstable suction transport
● Adhesive tack
● Changes in temperature and humidity
● Curl from winding
● Variation in manual application by workers
In other words, lamination misalignment is not just a material problem.
It arises from a combination of materials, processing, supply format, equipment conditions, and work conditions.
■ The Softer the Material, the More Easily It Shifts
Many thermal management materials are soft.
For example,
● Gels
● Greases
● Flexible heat dissipation sheets
● Adhesive materials
● Foam materials, and so on.
Soft materials are advantageous for contact.
However, their shape is less stable, and they can shift easily during lamination.
In other words, materials that make good contact can also be
materials that are hard to apply.
■ The Thinner the Material, the More Easily It Shifts
Thin materials also require care.
Thin films and sheets may
● Stretch
● Wrinkle
● Stick due to static electricity
● Flutter during transport
● Lift when peeled
In other words, the further thinning advances, the more difficult lamination accuracy becomes.
In future industries, miniaturization, thinning, and higher density will advance.
That is why the problem of lamination misalignment will become even more important in the future.
■ The Researcher's Perspective: Lamination Misalignment Is a Mounting Error
In research and development, material properties and thermal analysis are emphasized.
In actual products, however, components are not necessarily in their designed positions.
Lamination misalignment is a mounting error.
This mounting error affects
● Thermal resistance
● Insulation distance
● Waterproof lines
● EMI performance
● Contact area
In other words, even at the research stage, design that assumes misalignment, not just ideal placement, is important.
■ The Shop-Floor Perspective: Assume That Lamination Misalignment Will Always Occur in Volume Production
On the shop floor, it is difficult to reduce lamination misalignment to zero.
What matters is not only not shifting.
It is designing so that performance is unlikely to break even if it shifts.
For example, ways of thinking such as
● Allowing positional tolerances
● Giving component areas some margin
● Making insulating layers slightly larger
● Devising release liners
● Making shapes that are easy for automated machines to pick up
● Clarifying lamination reference points
are necessary.
■ Problems That Tend to Occur with Lamination Misalignment
In volume production processes, the following kinds of problems can occur.
● Heat dissipation materials coming off the heat source
● Insufficient contact area
● Edge lifting
● Air bubble entrapment
● Insulating layers shifting
● Conductive materials becoming exposed
● Waterproof lines breaking down
● EMI material positions shifting
● Adhesive material squeezing out
● Unstable application positions on automated machines
These affect not only thermal performance but also insulation, waterproofing, noise, reliability, and yield.
■ What to Check to Reduce Lamination Misalignment
To reduce lamination misalignment, the following must be checked.
● Whether the material stretches easily
● Whether the release liner peels stably
● Whether it is easy to pick up by suction on automated machines
● Whether the application reference is clear
● Whether positioning holes or reference shapes are needed
● Whether the adhesive tack is appropriate
● Whether it meanders during reel supply
● Whether its dimensions change with temperature and humidity
● Whether interlayer misalignment occurs during lamination
● Whether an allowable misalignment range has been designed
In other words, lamination misalignment countermeasures are not just material selection, but process design.
■ OTIS's Perspective
OTIS is not a company that develops thermal materials themselves.
However, we may be able to contribute in the area of processing thermal management materials into forms that are easy to apply in the correct position and supplying them stably in volume production.
What matters from OTIS’s perspective is
● High-precision die-cutting
● High-precision lamination
● Lamination of dissimilar materials
● Shape design that makes positioning easy
● Release liner design
● Reel supply
● Supply formats for automated processes
● Lamination accuracy
● Dimensional stability
Lamination misalignment cannot be solved by material performance alone.
Processing into shapes that are unlikely to shift and
creating supply formats that are unlikely to shift are important.
■ What OTIS Can Do
At OTIS, through
● Heat dissipation sheet processing
● TIM processing
● Graphite processing
● Insulating material processing
● Adhesive material processing
● EMI material processing
● Waterproof tape processing
● High-precision die-cutting
● Microfabrication
● High-precision lamination
● Lamination of dissimilar materials
● Reel supply
● Designing supply formats for automated processes
and more, we may be able to contribute to suppressing lamination misalignment and bringing multifunctional components closer to a state in which they can be used stably in volume production.
■ Outside OTIS's Expertise
On the other hand, OTIS is not a company that specializes in
● Development of materials themselves
● Structural design of customers’ entire products
● Design of automated machines themselves
● Dedicated thermal simulation analysis
● Dedicated EMI analysis
However, in the area of making thermal management components into forms that are easy to place in the correct position and stabilizing them in volume production processes,
we may be able to play an important role.
■ Industries Where This Technology Will Be Important
★★★★★ AI servers
★★★★★ EVs and batteries
★★★★★ ESS and energy storage systems
★★★★★ Smartphones
★★★★☆ Wearable devices
★★★★☆ Robots
★★★★☆ Communication equipment
■ Summary
Thermal management materials function only when applied in the correct position
In thermal management, material performance tends to attract attention.
In reality, however, performance changes just from a shift in the lamination position.
Lamination misalignment causes
● Coming off the heat source
● Reduced contact area
● Air layers
● Shifted insulating layers
● Broken waterproof lines
● Weakened noise countermeasures
In other words, lamination misalignment affects not only heat but multiple functions.
That is precisely why, in thermal management, not only what to use,
but also where, how accurately, and how it is applied is important.
Thermal management materials are not complete as materials alone.
They deliver their true performance only when applied in the intended position, in the intended shape, and without misalignment even in volume production.
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.
