Conformal cooling channel design of injection mold.

1. 2012
Moldex3D R11
European
Webinar
Series
Conformal Cooling Industrial Application
and Design Optimization Technology

2. Definition
Con-for-mal
adj.
1. :Leaving the size of the angle between corresponding curves
unchanged
2. of a map: representing small areas in their true shape
Origin:
Late Latin conformalis having the same shape, from Latin
Com- + formalis formal, from forma
First known use: 1893
Source:/www.merriam-webster.com/dictionary
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3. Dr. Andrew Hsu
» Current position:
CoreTech System senior engineer
» Education:
Ph.D. of Mechanical engineering
in University of California, Davis
» Research area:
Aerodynamics, heat transfer, numerical analysis,
advanced injection molding process (conformal
cooling, GAIM/WAIM
Dr. Hsu joined CoreTech System (Taiwan) in 2010. His recent research is focus on CAE
and several advanced injection molding fields such as gas/water assisted injection mold,
injection compression molding, optical parts, and conformal cooling.
Dr. Hsu has several years teaching experience in professional fields such as heat
transfer and injection molding. He have assisted several famous injection molding
manufacturers to solve real industry cases worldwide. His teaching combines theories
and practical cases which offers a thorough understanding for those from novice to
experienced professionals in injection molding field.
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4. Contents
> Introduction
– What and why is conformal cooling
– Benefits
> Mold Heat Transfer
– Conduction, Convection, Radiation
> Conformal Cooling Design and Manufacturing
– Design
– Manufacturing: laser sintering and vacuum brazing
> CAE Analysis on Conformal Cooling
> Case Study
– Carriage model
– Cup model
> Summary
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5. Introduction

6. Injection Molding Procedures
Cooling Stage
Mold open/Ejection
Mold Close
Screw moves forward
Filling Stage
Packing Stage
Nozzle shut off
Screw moves backward
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7. Advanced Injection Molding Processes
> Goals:
Shorten cycle time
Material saving
Quality improvement
Gas/Water assisted injection molding
- Weight reduction(~40%), improve product
quality, reduce cooling time
Conformal Cooling
- Reduce cooling time (20-60%)
- Improve product quality
Variotherm
- Improve product quality
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8. Cooling channel design
Q:What’s the best design for these products?
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9. Introduction of Conformal Cooling
> What is conformal cooling?
– Cooling channel design based on product contour.
> Why is conformal cooling?
– To increase cooling efficiency. With conformal cooling, cooling rate
difference can be minimized through the whole part.
– To reduce cycle time and cost
– To have better product quality
Source: EOS whitepaper, Siegfried Mayer (EOS GmbH)
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10. Introduction of Conformal Cooling
> When to use conformal cooling?
– For products with complex geometry. In order to remove heat from
areas where traditional tooling method can not reach.
> How to manufacture conformal cooling channels?
– DMLS (Direct Metal Laser-Sintering) and vacuum brazing methods
are usually applied. Traditional drilling method may have problems
in manufacturing conformal cooling system.
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11. Introduction of Conformal Cooling
> Some examples
From http:www.3dinnovation.dk/conformal_cooling_eng.htm
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12. What are the benefits of conformal
cooling?
> Problems on polymer molding
– Sink mark
– Warpage
– Cycle time
> Use conformal cooling during the injection molding
process to:
– Improve product quality such as warpage and sink
mark
– Decrease cycle time
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13. Mold Heat Transfer

14. The importance of heat dissipation
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15. Cooling system components
> Contains components like:
– Mold Temperature Controller
– Regular Channel
– Manifold
– Hose
– Others：Baffle or Bubbler
Insulated
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16. Mold Heat Transfer
> Heat Transfer Modes:
– Conduction
– Convection
– Radiation
> Heat Transfer Considered in Injection Molding:
– Heat removed from cavity to mold base
– Heat removed from mold base to cooling channels
– Mold surface radiation
– Mold surface convection
– Heat removed at ejection
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17. Heat Conduction and Convection
> Cooling system design and cooling time:
• Heat Conduction between cavity and cooling channels (Fourier’s Law):

"


dq
dT
q 
 k T  k 
Adt
dx
c
• Heat convection equation
inside cooling channels:

"

dq
q 
 hT  h(T 4  T 3)
Adt
• Coolant Type
• Coolant velocity
• Cooling channel diameter b
• Coolant temperature
h: conv. heat transfer coefficient
Cavity
b
Cooling
Channel
Mold base
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18. Conformal Cooling Design and
Manufacturing

19. Cooling Channel Design Parameters
• Three parameters on cooling channel design:
Distance between pipe and cavity: c
Distance between pipes: a
Pipe diameter: b
Theoretically, c should be as smaller as possible. And the values of a and b are
dependant. However, mold strength and lifecycle is a great concern.
So, there is a experimental design guideline for the three parameters as shown in the
table.
Source: EOS whitepaper, Siegfried Mayer (EOS GmbH)
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20. Conformal Cooling Channel Design
Source: EOS whitepaper, Siegfried Mayer (EOS GmbH)
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21. Conformal Cooling Manufacturing
Matsuura
Direct Metal Laser Sintering Machine
LUMEX Avance-25
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22. Conformal Cooling Manufacturing
LUMEX
①Powder Supply
Repeat 10
times
②Laser Sintering
10 times
③Milling
Repeat
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23. Vacuum Brazing
> Brazing is a metal-joining process whereby a filler
metal is heated above and distributed between two or
more close-fitting parts by capillary action.
> The filler metal is brought slightly above its melting
(liquidus) temperature while protected by a suitable
atmosphere, usually a flux. It then flows over the base
metal (known as wetting) and is then cooled to join
the workpieces together. It is similar to soldering,
except the temperatures used to melt the filler metal
are above 450 °C (842 °F).
> Vacuum brazing is a materials joining technique that
offers significant advantages: extremely clean,
superior, flux-free braze joints of high integrity and
strength.
Source: http://en.Wikipedia.org
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24. CAE Analysis on Conformal
Cooling

25. Moldex3D Solution for Conformal
Cooling
> For any complex cooling channel design. Meshing can be
constructed in Moldex3D with ease.
> STL format files can be imported and defined as cooling
channel or heating rod in Designer.
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26. Moldex3D Solution for Conformal
Cooling – eDesign procedures
Step 1: import part and runner
Step 4: generate mesh
Step 2: import .stl cooling channel
Step 3: define attribute as “cooling channel”
Step 5: export file for simulation
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27. Moldex3D Solution for Conformal
Cooling – Solid procedures
Step 1: import part and runner model in Rhino
Step 4: construct BLM/hybrid solid mesh
for cooling channels
Step 2: build runner/cavity solid mesh
Step 3: import cooling channel file
Step 5: build mold base solid mesh
Step 6: export solid model
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28. Moldex3D Solution for Conformal
Cooling
> Cooling time and transient mold temperature can be
estimated. The right figure shows the temperature
animation.
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29. Moldex3D Solution for Conformal
Cooling
> The flow properties (temperature, pressure, velocity) inside
the cooling channels can be estimated in 3D.
R11 Solid only
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30. Moldex3D Solution for Conformal
Cooling
Moldex3D can:
 Predict required coolant flow rate to fit production cycle
time
 Predict possible pressure loss in your cooling channel
design
 Prevent vortex/dead water area in your cooling channel
design
 Simulate baffle/bubbler designs in a true 3D approach
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31. 1. Carriage Model
> As shown in the figure below, the hallow interior of this
part is the crucial area. With traditional cooling channel
design, this is mostly the area with heat accumulation.
This will cause inward warp during injection molding
process.
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32. Cooling Channel Design
> The conventional design has no cooling channel inside
the hallow interior. With conformal cooling design, warp
can be reduced.
Conventional
Conformal
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33. Cooling Analysis – Cooling
Temperature
Conventional Cooling
Cooling Temperature
60.650 ~ 114.647 ℃
Conformal Cooling
Cooling Temperature
60.388 ~ 69.126 ℃
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34. Cooling Analysis – Cooling Time
Conventional Cooling
Cooling Time
Conformal Cooling
Cooling Time
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35. Cooling Analysis – Cooling
Efficiency
Conventional Cooling
Conformal Cooling
Cooling Efficiency
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36. Cooling Analysis – Mold Temp
Difference
Conventional Cooling
Mold Temp Difference
Conformal Cooling
Mold Temp Difference
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37. Cooling Analysis -- Mould
Temperature
> The two figures below show the mould temperature
distribution of conventional and conformal cooling
design. We can see the maximum temperature drops
from 114.7 ℃ to 69.2 ℃
Conventional Cooling
Conformal Cooling
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38. Result Summary
> For this case, the z-direction warp is the most concerned
point. Compare the conventional cooling system design
with conformal design, z-direction warp reduced by 87%.
Conventional
Conformal
Improved
(%)
X
-0.2512 ~
0.2439 mm
-0.2585 ~
0.2499 mm
-3
Y
-0.113 ~ 0.133
mm
-0.098 ~
0.12mm
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Z
-0.677 ~ 0.655
mm
-0.084 ~
0.086 mm
87
Total
0.001 ~ 0.685
mm
0.001 ~
0.265mm
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Displacement comparison
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39. Result Summary
> From the photo of actual product, we can also see the
warpage improvement is significant in z direction.
Conventional Cooling
Conformal Cooling
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40. 2. Cup Model
•Length： 90 mm
•Width： 90 mm
•Height：120 mm
•Thickness：
2 mm
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41. Product temperature -- Baffle
Temperature
animation
Temperature range：
75~103 ℃
EOC product surface
temperature: 82~91 ℃
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42. Moldbase temperature -- Baffle
Temperature animation
Temperature range：
79~105 ℃
EOC mold temperature
range:79~91 ℃
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43. Temperature history at sensor nodes
Cooling rates at each node are not the
same, this will affect product quality. EOC
product surface temperature is 84~91 ℃,
temperature difference is 5~7 ℃.
Flow
Pack
Cool
Open
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44. Product temperature -- Conformal
Temperature
animation
Temperature range：
75~98 ℃
EOC product surface
temperature range: 80~82 ℃
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45. Moldbase temperature -- Conformal
Temperature animation
Temperature range：
79~98 ℃
EOC Moldbase
temperature:79~84 ℃
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46. Temperature history at sensor nodes
Cooling rates at each node are closer
than traditional cooling. EOC product
surface temperature is 80.5~81.5 ℃,
temperature difference is 2~3 ℃ .
Flow
Pack
Cool
Open
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47. Summary

48. Summary
> Conformal cooling is an effective way to shorten cycle
time and improve product quality at the same time.
– In carriage model:
• warpage in z direction improve 87%
• cooling time shorten 61%.
– In cup model:
• cycle time reduction up to 42%
> Moldex3D can predict:
– Transient mold/part temperature
– Coolant physical properties
– Cooling time and efficiency
which is a useful tool for conformal cooling design validation.
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49. Thank you for your attention!

50. Contact Information
Dr. Hsu
andrewhsu@moldex3d.com
Larry
larryren@moldex3d.com
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