■ Irregular-Shape Lamination Has High Lamination Difficulty
Stacking full-surface films.
Relatively easy to align.
Small irregular-shaped components are
placed at specified positions,
and another component is stacked on top.
Positional accuracy becomes difficult.
In other words, in irregular-shape lamination,
lamination equipment, positioning technology and carrier design
are important.
■ The Smaller the Component, the Harder Positioning Becomes
A 5 mm square component is placed at ±0.2 mm.
The positional deviation rate is large.
Furthermore, if it is
thin,
soft,
and transparent,
the difficulty rises.
In other words, microfabrication and irregular-shape lamination are closely related.
■ Fixing Position on a Carrier
Small irregular-shaped components are hard to handle when separated into individual pieces.
They are held on a liner or carrier.
A reference position is created.
The next material is laminated in that state.
In other words, the carrier plays the role of a jig that supports the positional accuracy of irregular-shape lamination.
■ Providing Recognition Holes and Marks for the Process
Not needed in the final product.
But needed during processing.
For example,
position recognition holes,
tabs,
and alignment marks
are provided.
They are removed after lamination is complete.
In other words, in irregular-shape lamination, not only the finished shape but also the shape during processing is designed.
■ Temporary Fixing Followed by Final Pressing
If irregular-shaped components are bonded strongly all at once, the position may shift.
So the process is
temporary fixing with low-tack adhesive,
position confirmation,
and final pressing.
This can sometimes increase accuracy.
In other words, adhesive technology can also be used for positional accuracy.
■ Accuracy Changes with Lamination Order
Material A is applied first.
B on top of it.
Then C.
That is one order.
On the other hand,
B and C are integrated first,
and finally applied to A.
Which is better?
It changes depending on
material size,
softness,
and positional accuracy.
In other words, lamination order is also part of process design.
■ Decide the Reference Material
The material with the highest dimensional stability.
For example, a thicker PET carrier.
Using this as the reference,
copper foil,
TIM,
and insulating material
are placed.
Then the overall position is easier to stabilize.
In other words, rather than treating multiple materials equally,
there is also the idea of using one material as the reference framework.
■ Laminating First and Then Cutting the Outer Shape
Multiple materials are aligned.
Then the finished outer shape is die-cut all at once.
This method makes it easier to align the outer shape position.
However, the difficulty of die-cutting dissimilar materials simultaneously increases.
In other words, it is necessary to consider the balance of
positional accuracy
and cutting quality.
■ Processing Irregular Shapes First and Then Laminating
Each material is processed into the required shape.
Then laminated.
It is easier to optimize processing conditions for each material.
On the other hand, lamination positional accuracy is difficult.
In other words, in irregular-shape lamination, there is no universal process order.
An optimal process must be created for each project.
■ Lamination Using Half-Cutting
Irregular-shaped components are left on the liner.
Only unnecessary parts are removed.
In that state, they are transferred and laminated onto another material.
This allows small components to be laminated while being held.
In other words, half-cutting is also important in irregular-shape lamination.
■ The Concept of Transfer Processing
Irregular-shaped components on liner A
are transferred to another substrate B.
This is repeated to place multiple materials.
In other words, beyond
cutting
materials, a process that moves and transfers them to the required position is sometimes needed.
■ Managing Accumulation of Positional Deviation
Material A ±0.1 mm.
B ±0.1 mm.
C ±0.1 mm.
The more processes there are, the more relative deviation accumulates.
That is why, working backward from the final functional position,
the accuracy of each process is determined.
In other words, the idea of allocating process tolerances from the final tolerance is needed.
■ Not Everything Needs to Be High Precision
For example,
the insulation boundary is ±0.1 mm,
while the adhesive perimeter may be ±0.5 mm.
In this way, the required accuracy differs by function.
Making everything the minimum tolerance raises costs.
What matters is using different accuracies for each function.
■ In Irregular-Shape Lamination, Visual Inspection Alone Is Not Enough
The outer shape is clean.
But it is necessary to check whether
the overlap between materials A and B,
the insulation edge position,
and the adhesive area
are correct.
In other words, the inspection target is not individual dimensions but the relationships between materials.
■ Transparent Materials Sometimes Become Invisible After Lamination
Transparent insulating film
and transparent adhesive
are stacked.
Boundaries are hard to see from the outside.
That is why position is inspected during processing.
Or recognition marks are used.
In other words, functions that become invisible after completion
must be assured within the process.
■ Metal Foil Is Easy to Recognize by Imaging but Reflective
Copper foil and aluminum foil have easily visible contours.
On the other hand, they reflect light.
Depending on camera conditions, contour recognition may become unstable.
In other words, in irregular-shape lamination,
inspection lighting and recognition methods must be adjusted for each material.
■ Foreign Matter at Material Boundaries Becomes a Problem
Foreign matter at boundaries between multiple materials.
Part lifts.
A step forms.
Thermal resistance increases.
Insulation risk.
These result.
In other words, in irregular-shape lamination, there are many material interfaces, so foreign matter control is also important.
■ The Smaller the Irregular Component, the Greater the Impact of Foreign Matter
The component is 5 mm.
The foreign matter is 0.1 mm.
Relatively large.
In other words, with fine irregular-shaped components,
fine particles that were not previously a problem become a problem.
Requirements for clean processing also increase.
■ The More Edges There Are, the Greater the Risk of Delamination
Complex shapes have many
corners,
notches,
and narrow parts.
In other words, edges also increase.
Stress tends to concentrate at edges.
With
thermal cycling
and vibration,
they can become starting points for delamination.
In other words, the more complex the shape, the more durability must also be considered.
■ The Meaning of Rounding Sharp Corners
Sharp inside corners.
Stress concentration,
tearing,
and delamination
are likely to occur.
If possible, add a radius.
This can sometimes improve processability and durability.
In other words, improving the drawing shape itself for volume production is also a role of the processing company.
■ For Narrow Bridges, Look at the Balance Between Function and Mass Producibility
Two large areas are connected by narrow material.
It is necessary as a heat path.
However, it may
break during processing,
deform during peeling,
and be unstable in volume production.
So it is made slightly thicker.
A temporary carrier is added.
In other words, design and process are considered as a set.
■ Overly Complex Irregular Shapes Also Increase Cost
The shape is complex.
The die is difficult.
Material yield is poor.
Waste stripping is difficult.
Inspection also increases.
In other words, complexity that is unnecessary for function should be avoided.
What matters is keeping only the necessary complexity.
■ Material Yield Changes Greatly with Irregular Shapes
L-shapes.
U-shapes.
Long, narrow shapes.
Depending on how they are arranged on the roll, material loss becomes large.
Rotating.
Nesting.
Staggered arrangement.
These can improve yield.
In other words, in irregular-shape lamination, even material costs relate to processing design.
■ Material Yield Also Changes with Lamination Order
Expensive material is applied over the entire surface first.
Then large amounts of waste are cut away.
Large amounts are discarded.
On the other hand,
expensive material is processed into irregular shapes first,
and only the necessary parts are laminated.
Yield improves.
This can be the case.
In other words, process design
is also directly linked to material costs.
■ It Is Worth Laminating Expensive Materials After Shaping Them
Graphite.
Special TIM.
High-performance metal foil.
These are expensive.
Rather than laminating over the entire surface and then discarding large amounts of unnecessary parts,
laminating only the required shapes can be advantageous.
This is where the value of irregular-shape lamination emerges.
■ However, Making It Too Small Raises the Cost of Positional Accuracy
To save material, it is made as small as possible.
Then there is no margin for positional deviation.
High-precision lamination is needed.
Equipment and inspection costs increase.
In other words, it is necessary to look for the optimal point between material yield and processing cost.
■ It Can Be Applied by Hand in Prototyping, but Is Difficult in Volume Production
Irregular-shaped components are aligned with tweezers.
That is possible in prototyping.
In volume production, it takes time.
Operator variation also appears.
So
carriers,
jigs,
reels,
and automatic application
are considered.
In other words, irregular-shape lamination is only established once the volume production method is designed too.
■ Irregular-Shape Lamination and Automation Are Closely Related
The customer applies components
A,
B,
and C
separately.
Automated equipment also needs three processes.
They are integrated on the OTIS side.
The customer applies only one component.
In other words, irregular-shape lamination has value as pre-processing that simplifies the customer’s automated process.
■ Reducing Processes Also Reduces Positional Deviation
The customer applies three times.
Positional deviation occurs at each process.
With an integrated component, once.
Relative positions are already controlled on the OTIS side.
In other words, reducing part count through lamination leads not only to fewer assembly man-hours, but also to stabilization of functional positions.
■ Integration into One Sheet Can Also Simplify Image Recognition
Recognizing three small transparent films separately.
Difficult.
A large recognition hole is provided in the integrated component.
The equipment recognizes it once.
In other words, irregular-shape lamination can sometimes also simplify recognition design on the customer’s equipment side.
■ Continuous Supply Through Reel Conversion
Irregular-shape laminated components are
arranged on a liner
at a fixed pitch
and in a fixed orientation.
Converted to reels.
The customer’s equipment peels and applies them.
This makes even complex components easier to automate.
In other words, by combining irregular-shape lamination and reel supply,
complex functional components are turned into simple volume production processes.
■ How Much Should OTIS Laminate?
Positional accuracy between materials A and B is very important.
Integrated at OTIS.
Material C can easily be applied on the customer’s equipment.
C is done on the customer’s side.
In this way, the division of processes is designed.
In other words, irregular-shape lamination is also process design for the supply chain.
■ Failure Example: Too Much Full-Surface Material Leads to Excessive Cost
The hot spot is only in one area.
But expensive graphite was placed over the entire surface.
Performance was good.
But the cost did not work.
It was changed to irregular-shape placement only where needed.
Material usage was reduced while maintaining performance.
In other words, this is an example where overall optimization was achieved through irregular-shape lamination.
■ Failure Example: The Opening Position of Insulating Material Shifted and Blocked the Heat Path
An opening for TIM contact in the center.
But the lamination position shifted.
The insulating film covered part of the heat-generating surface.
Thermal performance worsened.
In other words, the relative accuracy between insulation position and thermal position was important.
■ Failure Example: The Irregular Shape Was Made Too Narrow to Be Peeled Automatically
To reduce material cost, the graphite width was made as narrow as possible.
It worked in terms of thermal design.
But it deformed when peeled from the liner.
It could not be transported stably by the equipment.
As a result, the width had to be increased slightly.
In other words, minimum material usage and minimum total cost are not the same.
■ Failure Example: TIM Lifted Due to a Step from Stacked Materials
Partial metal foil on top of insulating material.
Then TIM.
A step formed only at the metal foil area.
The TIM did not make full-surface contact.
Thermal resistance increased.
In other words, it was necessary to consider not only lamination position but also thickness distribution in the Z direction.
■ Failure Example: Integration Succeeded in Prototyping, Boundary Delamination After Thermal Cycling
Different materials were laminated in irregular shapes.
Initial performance was good.
After thermal cycling, delamination occurred from material boundaries.
The cause was thermal expansion differences and stress concentration.
In other words, initial positional accuracy alone could not guarantee long-term performance.
■ The Researcher's Perspective: Irregular-Shape Lamination Is "Spatial Optimization of Materials"
Material A is excellent.
Material B is also excellent.
So they are stacked over the entire surface.
Rather than that idea, consider
where A is needed,
where B is needed,
and where nothing is needed.
In other words, irregular-shape lamination is
an evolution from the technology of choosing materials to the technology of optimally placing materials in space.
■ The Shop-Floor Perspective: Complex Shapes Have Reasons
Look at the drawing.
There are many notches.
There are small holes.
There are narrow parts.
Rather than immediately thinking about processing methods,
confirm
why it has this shape.
To avoid heat.
Insulation distance.
Avoiding screws.
Air release.
If the purpose is known, it may be possible to propose a shape that is easier to mass-produce.
■ Not Just Making the Customer's Drawing as Is, but Proposing a Workable Shape
If there are
overly narrow parts,
sharp corners,
and unnecessarily complex cutouts,
improvement proposals such as
adding a radius,
increasing width slightly,
and integrating two parts.
In other words, in irregular-shape lamination, the value of DFM is very large.
■ "Making It One Sheet" Is Not Valuable in Itself
Customer processes can be reduced.
Positional accuracy improves.
Material yield improves.
It becomes easier to automate.
Integrate when there are such effects.
In other words, the goal is not to make complex laminated components.
It is to simplify the customer’s product and the customer’s process.
■ OTIS's Perspective: Irregular-Shape Lamination Is the Area That Integrates OTIS's Processing Technologies
Irregular-shape lamination requires
high-precision die-cutting,
microfabrication,
thin-film processing,
partial adhesion,
high-precision lamination,
alignment,
and reel processing.
In other words, it is an area that combines the technologies from 10-1 to 10-6.
This is where OTIS’s expertise stands out strongly.
■ Process Design Capability, Not Single Processing, Is Tested
It does not work with dies alone.
It does not work with lamination alone either.
Material selection,
process order,
positional references,
carriers,
and inspection
are combined.
In other words, in irregular-shape lamination, the ability to assemble the entire process matters more than a single processing technology.
■ OTIS "Componentizes" Functions
Material manufacturers make
high-thermal-conductivity materials,
insulating materials,
adhesives,
and metal foils.
OTIS
processes them into the required shapes,
places them in the required positions,
integrates them,
and designs even the supply format.
In other words, OTIS can have the role of converting multiple material functions into a single mountable component.
■ Making Components Not Found in Material Manufacturers' Catalogs
Material manufacturers’ catalogs list
graphite sheets,
insulating films,
and double-sided tapes.
But what the customer wants may be a component with
graphite in the center,
insulation on the perimeter,
and adhesive in only part.
This is not a standard product of a single manufacturer.
In other words, there is value in a processing company making customer-specific functional components that combine multiple materials.
■ What OTIS Can Do
At OTIS, by combining
● Irregular-shape lamination
● Partial lamination
● High-precision lamination
● Partial placement of TIM
● Partial placement of graphite
● Partial placement of insulating materials
● Partial placement of copper foil and aluminum foil
● Partial placement of adhesives
● Partial placement of foams and seal materials
● High-precision die-cutting
● Microfabrication
● Thin-film processing
● Opening processing
● Slit processing
● Half-cutting
● Transfer processing
● Carrier design
● Positional accuracy control
● Reel-to-reel processing
● Image inspection
● Supply formats for automatic application
● Process design from prototyping to volume production
we can mass-produce integrated components in which multiple functional materials are placed in the required positions.
■ Outside OTIS's Expertise
OTIS is not a company that specializes in
● Formulation development of each functional material itself
● Thermal design of customers’ entire products
● Design of entire electrical circuits
● Design and manufacture of automatic application equipment itself
As needed, we work with material manufacturers, equipment manufacturers and customers’ design departments.
What OTIS takes on is
the area of placing multiple materials where they are needed, with the required accuracy, and turning them into a single volume production component.
■ Summary: Irregular-Shape Lamination Is a Departure from "Using High-Performance Materials Everywhere"
Thermal management.
Insulation.
Adhesion.
EMI.
Waterproofing.
Just because these functions are needed does not mean all materials must be stacked over the entire component.
Thermally conductive material only where heat should be released.
Graphite only in the direction heat should spread.
Insulating material only where insulation is needed.
Adhesive only where fixing is wanted.
Seal material only where sealing is wanted.
Placing only the necessary functions where they are needed.
This is the idea of irregular-shape lamination.
Material usage can be reduced.
Components can be made thinner.
Weight can be reduced.
Unnecessary heat paths can be prevented.
Multiple customer application processes can be combined into one.
But for that,
shape accuracy,
positional accuracy between materials,
thickness,
steps,
thermal expansion,
interfaces,
and automation
must be controlled.
In other words, irregular-shape lamination is more difficult than simple bonding.
In return, by combining the multiple technologies a processing company has, very great value can be created.
Placing functions where they are needed, rather than stacking materials over the entire surface.
What material manufacturers make is high-performance raw material.
What the customer needs is not that raw material.
It is specific functions within the product, such as
cooling only here,
insulating only here,
bonding only here,
and not letting heat flow here.
Turning that map of functions into real components through the lamination of thin-film materials.
That is the value of irregular-shape lamination 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.
