Conformal Cooling

Conformal Cooling Industrial Application

and Design Optimization Technology

2012

Moldex3D R11

European

Webinar

Series

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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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» 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.

Dr. Andrew Hsu

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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

Introduction

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Injection Molding Procedures

Cooling Stage Mold open/Ejection

Mold Close

Screw moves forward

Filling Stage

Packing Stage

Nozzle shut off Screw moves backward

7 7 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

8 8 8

Cooling channel design

Q:What’s the best design for these products?

9 9 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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> 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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> Some examples

From http:\\\www.3dinnovation.dk/conformal_cooling_eng.htm

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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

Mold Heat Transfer

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The importance of heat dissipation

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Cooling system components

> Contains components like:

– Mold Temperature Controller

– Regular Channel

– Manifold

– Hose

– Others：Baffle or Bubbler

Insulated

16 16 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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Heat Conduction and Convection

> Cooling system design and cooling time:

• Heat Conduction between cavity and cooling channels (Fourier’s Law):

• Heat convection equation

inside cooling channels:

• Coolant Type

• Coolant velocity

• Cooling channel diameter b

• Coolant temperature

h: conv. heat transfer coefficient

Cavity

Mold base Cooling

Channel

c

xd

dTkTk

Adt

qdq"

b

)( 34" TThTh

Adt

qdq

Conformal Cooling Design and

Manufacturing

19 19 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.


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Conformal Cooling Channel Design


21 21 21

LUMEX Avance-25

Direct Metal Laser Sintering Machine

Matsuura

Conformal Cooling Manufacturing

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LUMEX

①Powder Supply

②Laser Sintering

③Milling

10 times

Repeat 10

times

Repeat

Conformal Cooling Manufacturing

http://www.youtube.com/watch?v=fc9SVKTc8YI

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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

http://en.wikipedia.org/wiki/Liquidus

http://en.wikipedia.org/wiki/Flux_(metallurgy)

http://en.wikipedia.org/wiki/Soldering

CAE Analysis on Conformal

Cooling

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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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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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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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Cooling

> Cooling time and transient mold temperature can be

estimated. The right figure shows the temperature

animation.

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Cooling

> The flow properties (temperature, pressure, velocity) inside

the cooling channels can be estimated in 3D.

R11 Solid only

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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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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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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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Cooling Analysis – Cooling

Temperature Conventional Cooling Conformal Cooling

Cooling Temperature 60.388 ~ 69.126 ℃

Cooling Temperature 60.650 ~ 114.647 ℃

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Cooling Analysis – Cooling Time

Conventional Cooling Conformal Cooling

Cooling Time Cooling Time

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Cooling Analysis – Cooling

Efficiency Conventional Cooling Conformal Cooling

Cooling Efficiency

36 36 36

Cooling Analysis – Mold Temp

Difference Conventional Cooling Conformal Cooling

Mold Temp Difference Mold Temp Difference

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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 ℃


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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

11

Z -0.677 ~ 0.655 mm

-0.084 ~ 0.086 mm

87

Total 0.001 ~ 0.685 mm

0.001 ~ 0.265mm

61

Displacement comparison

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Result Summary

> From the photo of actual product, we can also see the

warpage improvement is significant in z direction.


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2. Cup Model

•Length： 90 mm

•Width： 90 mm

•Height：120 mm

•Thickness： 2 mm

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Product temperature -- Baffle

EOC product surface temperature: 82~91 ℃

Temperature range：75~103 ℃

Temperature

animation

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Moldbase temperature -- Baffle

EOC mold temperature range:79~91 ℃


Temperature animation

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Temperature history at sensor nodes

Flow Pack Cool Open

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 ℃.

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Product temperature -- Conformal

EOC product surface temperature range: 80~82 ℃


Temperature

animation

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Moldbase temperature -- Conformal


EOC Moldbase temperature:79~84 ℃

Temperature animation

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Flow Pack Cool Open

Cooling rates at each node are closer than traditional cooling. EOC product surface temperature is 80.5~81.5 ℃, temperature difference is 2~3 ℃ .

Temperature history at sensor nodes

Summary

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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.

Thank you for your attention!

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Contact Information

Dr. Hsu

[email protected]

Larry

[email protected]

Documents

Conformal Cooling