■ The More Components Are Applied Separately, the More Opportunities for Misalignment
For example,
insulating film,
TIM,
graphite,
and adhesive
are each applied in separate processes.
Suppose each process has an application error of ±0.2 mm.
Then the final relative positions may vary even more.
On the other hand, if they can be laminated with high precision in advance into a single component, the number of applications on the customer side can be reduced.
In other words, integrating components has significance not only for thermal performance, but also for stabilizing positional accuracy.
■ However, Integration Also Has Limits
Integrating multiple components has the advantages of
● Fewer processes
● Improved positional accuracy
However,
● Increased thickness
● Warping
● Increased thermal resistance
● Greater peeling difficulty
can also occur.
That is why it is not the case that anything should be integrated.
It is necessary to consider how far integration should be done on the processing manufacturer’s side, and what should be left to the customer’s process.
■ Loose-Piece Supply Can Make Volume Production Difficult
Small TIM pieces of a few mm are supplied loose in bags.
The customer takes them out one at a time.
Checks the orientation.
Applies them.
In small quantities, this can be handled.
But as quantities increase,
● Picking up
● Component orientation
● Foreign matter
● Work time
become problems.
In that case, reel supply makes automation easier.
■ Reel Supply Is Not Just Packaging
With reel supply, it is necessary to decide
component pitch,
carrier width,
liner,
peeling force,
component posture,
and winding direction.
In other words, a reel is
not a packaging format, but an equipment interface.
Being aware of this changes the role of the processing company.
■ Lamination Accuracy Becomes the Functional Accuracy of the Final Product
The insulating material shifts 0.5 mm.
The TIM shifts 0.3 mm.
The graphite shifts 0.5 mm.
These look like dimensional defects on a drawing.
In reality, however, they affect functions such as
insulation,
heat dissipation,
EMI,
and waterproofing.
In other words, lamination accuracy is not appearance quality, but functional quality.
■ Variation in Lamination Becomes Variation in Temperature
The same material.
The same product.
Yet
product A is 70°C,
product B is 75°C,
and product C is 80°C.
The cause may be not material lots, but differences in application state.
In other words, in volume production, it is also necessary to consider the possibility that
variation in thermal performance = variation in lamination quality.
■ Some Defects Cannot Be Inspected
After application,
the appearance is clean.
The position is also correct.
But there are small air bubbles inside.
The compression state differs in part.
This sometimes cannot be seen from appearance alone.
That is why it is difficult to guarantee everything by post-completion inspection.
In volume production, what matters is not only inspection, but creating a process in which defects are unlikely to occur.
■ Process Capability Must Be Examined
The first piece is per the drawing.
The tenth is also per the drawing.
That alone does not tell you about volume production stability.
What is needed is to look at data over a long period.
Position.
Thickness.
Application accuracy.
Air bubbles.
How much do these vary?
In other words, in volume production, it is necessary to look not only at averages but at distributions.
■ Die Wear Also Leads to Application Accuracy
Die-cutting dies wear as they continue to be used.
Then
outer shape,
hole positions,
and burrs
may change little by little.
When such components are applied automatically, changes in outer shape can also affect image recognition and positioning.
In other words, changes in the processing step chain into the subsequent application step.
■ Material Lot Differences Cannot Be Ignored in Volume Production
Even materials with the same part number can have a certain variation in
● Thickness
● Hardness
● Peeling force
● Surface condition
In prototyping, only one material lot is used.
In volume production, multiple lots are used.
Problems can first appear there.
In other words, it is necessary to think that prototype evaluation is only one example of a material lot.
■ Absorbing Worker Differences Through the Process
Even when manual work remains, it is important to minimize differences between workers.
For example,
positioning jigs,
tabs,
reference holes for application,
and easy-to-peel liners
are provided.
Rather than relying only on workers’ skill, it is made easy for anyone to create the same state.
In other words, a good process is not a process that skilled people can do, but a process that ordinary people can do stably.
■ Failure Example: 10 Prototype Units Succeeded, but Temperatures Varied Across 500 Production Units
In development, 10 units were assembled by hand.
All had good temperatures.
Volume production began, and application was switched to automated.
Then only some products were hot.
Investigation found variation in
TIM application position,
compression bonding conditions,
and air bubbles.
The material was the same.
The design was also the same.
But thermal performance changed because the manufacturing method changed.
This is a failure of thinking that prototype conditions could be transferred as-is to volume production.
■ Failure Example: Good Thermal Performance, but It Cannot Be Peeled
A very soft TIM with high thermal performance was adopted.
In prototyping, people could peel it with tweezers and apply it.
But automated machines could not peel it stably from the liner.
The component remained on the liner.
It deformed.
Takt time could not be achieved.
As a result, a material change was needed.
In other words, the supply format was not considered at the time of the adoption decision.
■ Failure Example: Full-Surface Adhesion Increased Air Bubbles
To prevent misalignment, full-surface adhesion was used.
Fixing strength increased.
But when large-area components were applied, air bubbles tended to remain in the center.
Thermal performance actually worsened.
In other words,
as a result of improving fixing performance,
contact thermal performance was worsened.
In thermal management, it is necessary to check whether improving one function breaks another.
■ The Researcher's Perspective: In Volume Production, "Variation" Matters More Than "Average Performance"
In prototyping, confirming peak performance is important.
In volume production, in addition, it is necessary to look at
worst-case values,
variation,
and change over time.
For example, even if the average temperature is 70°C,
it is a problem if some products reach 85°C.
In other words, in volume production, what matters is how to create minimum guaranteed performance, not peak performance.
■ The Shop-Floor Perspective: Look Not Only at Finished Products, but at the Application Process
A temperature defect appeared.
Change the material.
Before that, look at the application process.
Look at
peeling angle,
pick-up method,
application speed,
roller pressure,
and worker motions.
Then the cause may turn out to be in the process rather than the material.
Even in heat problems, it is important to look at the actual item, the actual site and the actual process.
■ OTIS's Perspective: Volume Production Lamination Is OTIS's Main Battlefield
Material manufacturers develop high-performance materials.
Equipment manufacturers make high-performance application equipment.
What is needed in between is
turning materials into forms that equipment can handle.
What OTIS can take on is
● Outer shape design
● Partial adhesion
● Half-cutting
● Carrier design
● Reel conversion
● Lamination
● Positional accuracy control
connecting materials to volume production processes through these.
This is one of the areas where the value of a processing company is most easily delivered.
■ Cutting per the Drawing Is Not Enough
A drawing is received from the customer.
It is processed as is.
Of course, that is also important.
But if volume production capability is also considered,
proposals can be made such as
“Won’t this narrow shape deform during peeling?”
“Won’t air bubbles remain with this full-surface adhesion?”
“Wouldn’t this component be easier to automate if made into a reel?”
In other words, a processing company can move from a company that reproduces drawings to a company that makes volume production processes work.
■ The Significance of Connecting Processing Companies and Equipment Manufacturers
To make automation work,
components alone are not enough.
Equipment alone is not enough either.
Compatibility between components and equipment is needed.
For example,
OTIS
→ Designs and processes reel components
Equipment manufacturer
→ Designs peeling, pick-up and application equipment
Customer
→ Presents actual volume production conditions
If these three parties design together, the accuracy of volume production start-up can be raised.
In other words, it is important to look at components + equipment + customer process as one.
■ What OTIS Can Do
At OTIS, through
● High-precision die-cutting
● Thin-film processing
● Microfabrication
● TIM processing
● Graphite processing
● Insulating film processing
● Adhesive processing
● Partial adhesion
● Opening processing
● Slit processing
● Half-cutting
● High-precision lamination
● Lamination of dissimilar materials
● Carrier design
● Reel-to-reel processing
● Component design for automated application
● Image inspection
● Stabilization of volume production conditions
we can process thermal management materials into components that are easy to apply in volume production.
■ Outside OTIS's Expertise
OTIS is not a company that specializes in
● Design and manufacture of automated application equipment itself
● Robot control
● Development of image recognition algorithms themselves
● Development of thermal materials themselves
As needed, we collaborate with equipment manufacturers, material manufacturers and customers.
What OTIS should take on is making the component side work between materials and volume production equipment.
■ Summary: Being Able to Apply It in Prototyping Is Not Proof That It Can Be Mass-Produced
In prototyping, people can make corrections.
If the position shifts, they fix it.
If there are air bubbles, they remove them.
If it will not peel, they peel it slowly.
But in volume production, those judgments cannot be left to people every time.
What is needed are components and processes that
are positioned correctly,
are unlikely to trap air bubbles,
are easy to peel,
are easy to pick up,
are unlikely to deform,
can be applied automatically,
and end up in the same state no matter how many tens of thousands are made.
In other words, in bringing thermal management materials to volume production, material performance alone is not enough.
Lamination itself must be designed.
Making one piece well in prototyping and making ten thousand pieces in the same state in volume production
are completely different technologies.
And to make thermal performance work as product performance, the latter technology is needed.
That is why, in thermal management for volume production,
design is only complete when it considers not only “Does this material cool?” but also “Can this material be applied in the same state every time?”
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.
