Advanced Energy Transfer Systems Thermoset Molding

1/31/2011 © Acrolab 20111

Acrolab

Energy Transfer Systems

for

Thermoset Injection Molds

Joe Ouellette

Chief Technology Officer

Acrolab Ltd.

Advanced Thermal Engineering Research & Development

Products and Services

1/31/2011 © Acrolab 20112

Overview

Heating injection thermoset molds in a uniform manner

to achieve near isothermal mold face conditions is a

critical requirement for dimensionally sensitive

engineered products.

This presentation will highlight a case study that will

address a technologically advanced heating system

which provides near isothermal mold face conditions in

conjunction with rapid thermal energy throughput. This

system offers faster overall molding cycles, more

consistent product performance outcomes, simplified

maintenance and reduced down time.

1/31/2011 © Acrolab 20113

Case Study #1: Headlight Housing

Automotive headlight

reflector housings present

a particular challenge in

injection thermoset mold

processing.

The following presentation

will specifically deal with

these types of molds.

1/31/2011 © Acrolab 20114

Thermoset headlight reflector bodies/ headlight assembly

1/31/2011 © Acrolab 20115

Acrolab - Advanced heating system methodology

The heating system consists of a matrix of heatpipes

embedded in the mold inserts incorporating the working faces

of the mold. The mass energy input for the mold is provided

through a series of distributed watt density cartridge heaters

located remote from the mold face.

These heaters interact with the heatpipe matrix to provide a

uniform thermal energy transfer to the mold face.

Thermocouples mounted proximate to the mold face control

power to the heaters. A unique heated mold component

provides heat to the sprue cone to decrease the cure time of

the sprue.

1/31/2011 © Acrolab 20116

Integrally Heated

Sprue Spreader Pin

Sprue Spreader

extension

Heaters

Heatpipes

Thermocouples

Acrolab – Advanced energy transfer system

1/31/2011 © Acrolab 20117

System Components

Isoball® heat pipes

Distributed watt density cartridge heaters

Type J adjustable bayonet thermocouples

Integrally heated Sprue Spreader c/w thermocouple

1/31/2011 © Acrolab 20118

Component Features and Benefits

Distributed Watt Density Cartridge Heaters

Cartridge heaters are of a swaged construction to permit the most efficient transfer of heat to the O.D. of the heater

The pitch of the winding within the element is increased at each end to provide a linear thermal output over the length of the heater.

Uniform Temperature

Length

Temp

Cartridge Heater

1/31/2011 © Acrolab 20119

Standard Heater

Linear pitched winding with the standard cartridge results

in a nonlinear heat output with 50% of the energy of the heater

being generated in the center 33% of the heater length.

D TTemp

Length


Cartridge Heater

1/31/2011 © Acrolab 201110

Normal pitch

windings

Distributed wattage

pitched windings


Distributed Watt Density Cartridge Heaters

1/31/2011 © Acrolab 201111



Adjustable thermocouples (TCs) are installed in proximity tothe mold face.

TCs are installed in pairs to provide an on boardreplacement in the event of TC failure.

1/31/2011 © Acrolab 201112


Spring Loaded

Type J

Ungrounded Thermocouple


1/31/2011 © Acrolab 201113

Integrally heated Sprue Spreader and onboard thermocouple

Using a proprietary process, the Heated Sprue Spreader Pin isconstructed as a swaged distributed wattage heater integrally heated andcontrolled with its own on board replaceable TC.

The heated sprue pin now actively cures the sprue while directing theresin to the runners and gates.

Typically the resin sprue is the thickest cross section and takes the longesttime to cure.

Component Features and Benefits – Isosprue™ Spreader

1/31/2011 © Acrolab 201114

Component Features and Benefits – Isosprue™ Spreader

1/31/2011 © Acrolab 201115

Ball Radiused Heatpipes

Heatpipes are super thermal conductors whichtransfer energy at rates in excess of 10,000time the speed of metals.

Heatpipes are isothermal devices that do notrequire electrical power.

Ball radiused heatpipes are designed to beinstalled in holes with matching ball radii. Theradii prevent stress cracks from forming.

A matrix of heatpipes draw energy from aremote bank of heating elements and uniformlytransfer that energy to the mold face.

Component Features and Benefits – The Isoball™

1/31/2011 © Acrolab 201116

Heatpipe Function Schematic

Component Features and Benefits – The Isoball™

1/31/2011 © Acrolab 201117

Heating System Methodology

The next graph shows the time to steady state and themagnitude of that thermal steady state for one inch diameterby six inch long bars of various materials as well as anIsoball™ heatpipe of the same geometry.

All bars were uninsulated and oriented vertically on atemperature controlled hot plate maintained at 350º F.Thermal bridging compound of the type used in installing theheating system was used to bridge the gap between the hotplate and the end of the bars.

1/31/2011 © Acrolab 201118

Isoball™ heatpipe vs. various metal bars of common geometries

Thermal Transients to Steady State

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

0 5 10 15 20 25 30 35 40 45 50 55 60 65

Time (minute)

Tem

p. (

deg

. F)

Isobar-Top

Copper rod-Top

Steel rod-Top

Alu. Rod-Top

Tem

p°

F

Time [min]

1/31/2011 © Acrolab 201119


Historically each of these materials have, at one time or another, been installed in hardened inserts to promote rapid heat transfer.

The heatpipe achieved the highest level of thermal steady state after the shortest interval.

1/31/2011 © Acrolab 201120

Of particular note, all of the metal bars with the exception of

the heatpipe demonstrated a significant delta T from end to

end both during the transient to steady state and at steady

state.

The heatpipe remained Isothermal during both the transient

and at steady state.

The difference between the steady state temperature of the

heatpipe and the temperature of the hot plate is due to losses

to the atmosphere.


1/31/2011 © Acrolab 201121

Core and Cavity

Left and Right hand – “theoretical headlamp reflector mold”

System Design

1/31/2011 © Acrolab 201122


Every heating system is custom engineered to insure the

matrix of heatpipes is optimally developed to provide heat

energy uniformly to the mold working faces based on the

geometry of the part being molded.

A remotely located heater bank is situated either within the

mold inserts, within the holder block or within the holder block

backing plate.

In all instances these heaters are positioned to thermally

integrate with the heatpipe array so that all the energy

generated is redistributed at high speed by the heatpipes.

1/31/2011 © Acrolab 201123


When design considerations require that the heaters are not

integral with the inserts, heatpipes are designed with lengths

to bridge the thermal break which occurs at the mating

surfaces of the inserts. Heatpipe lengths extend to permit

close proximity with the remote heaters.

Heatpipes incorporate a spherical radiused end to mate with

a spherical radius at the bottom of all installation holes. This

assures no stress cracking and places the thermodynamic

action for the heatpipe closest to the mold face.

1/31/2011 © Acrolab 201124


When heaters are installed within the inserts, their length is

defined by the insert. Spacers are installed at either end of

through holes that line up with the insert heater holes. These

spacers position the heater within the insert.

In all cases, heaters are installed in through-holes to permit

extraction via push rods if necessary.

All heaters are wired to local terminal blocks mounted in the wire

channel. The wiring harness is attached to these terminal blocks

and resides permanently in the mold.

1/31/2011 © Acrolab 201125


Thermocouples are mounted through the back plate of the

tool and are wired to local terminal blocks. All control zones

have both an active thermocouple and a spare, both wired to

the wire harness.

The terminations for the thermocouples can be found in the

terminal box for each half of the mold.

If a thermocouple fails, its spare can be connected to the

control system by jumpering to the spare terminals.

1/31/2011 © Acrolab 201126

Heatpipe Matrix

in a

cavity insert[prior to insertion]

Example:

1/31/2011 © Acrolab 201127

System Design

Core insert Isoball™ heatpipe array

1/31/2011 © Acrolab 201128

Cavity insert Isoball™ heatpipe array

System Design

1/31/2011 © Acrolab 201129


The isoball™ heatpipe matrix is custom engineered to

assure that the whole insert is dynamically responsive to

temperature changes and reactive to thermal throughput

demands.

The next slide shows an acceptable and unacceptable

array configuration.

1/31/2011 © Acrolab 201130

Detailed view: Heatpipe Matrix

3.875

2.652

6.8xØ

2.652

6.8xØ

Additional Cooling Required

1.624

2.6xØ

1.875

3xØ

1.875

3xØ

1.875

3xØ

ARRAY DESIGN FOR Ø5/8

1.875

3xØ

1.875

3xØ

3.875

System Design

Non reactive heated areas

1/31/2011 © Acrolab 201131

Ball radiused

heatpipes

Distributed wattage

cartridge heaters

Type J adjustable

thermocouples

Electrical

Terminal Boxes

System Design

1/31/2011 © Acrolab 201132

System Design – 4 configurations

1/31/2011 © Acrolab 201133

Heatpipes remain within the inserts to integrate with heaters also within

the inserts.

Guard heaters

in the holder block

System Design

1/31/2011 © Acrolab 201134

Heatpipes within the inserts. Heaters located in the holder block

System Design

1/31/2011 © Acrolab 201135

Heatpipes extending from the inserts through the holder block to

integrate with heaters in the holder block.

System Design

1/31/2011 © Acrolab 201136

Heatpipes extending from the inserts through the holder block to

integrate with heaters in the holder block clamp plates

System Design

1/31/2011 © Acrolab 201137

Sprue Spreader

installed to core out

the sprue cone

and cure the cone

independently

sprue bushing

Local terminal block

for the Sprue Spreader

and thermocouple

Sprue spreader extension

cut to size and made

from a core sleeve section

Isosprue ™Spreader System Design

1/31/2011 © Acrolab 201138

Isosprue spreader animation is located on this disk in a separate AVI file.

Isosprue spreader animation

1/31/2011 © Acrolab 201139

System Assembly

1/31/2011 © Acrolab 201140

The system is electrically installed using locally mountedterminal blocks located in wiring troughs adjacent to the exits ofthe heaters and thermocouples.

Each thermocouple and heaters are independently wired to itsindividual terminal block. A wiring harness is permanently set intothe wiring trough to bring the connections to the main terminalbox for the core and cavity.

Multipin receptacles mounted on the box ends provide interfacewith a multizone control system.

System Assembly

1/31/2011 © Acrolab 201141

Termination

box showing

the wiring

harness,

terminal strips

and multipin

receptacles

System Assembly

1/31/2011 © Acrolab 201142

Heating System

Multipin

Receptacle

Multipin receptacles are

used for both power and

thermocouple connections

on both the cavity and core

halves of the mold.

System Assembly

1/31/2011 © Acrolab 201143

System Schematic Methodology

The covers of the main termination boxes on the

mold are placarded with both physical location

schematics of the heater and thermocouple exit

points.

An electrical schematic of the heater wiring and

thermocouple wiring scheme from the terminal

strips to the multipin receptacles on the box

ends is also mounted.

1/31/2011 © Acrolab 201144

ZONE#9 ZONE#10 ZONE#13ZONE#14

ZONE#11 ZONE#12 ZONE#16 ZONE#15

HTR

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9,

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HTR

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HTR

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HTR

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HTR

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HTR

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HTR

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5,

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HTR

#3

6,

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x 1

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HTR

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HTR

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3,

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x 1

5.7

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HTR

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13

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HTR

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x 1

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5", 1

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HTR

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9,

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x 1

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TC

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STC

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TC

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ATC

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STC

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ATC

#3

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TC

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ATC

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TC

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TC

#6

STC

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A

TC

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TC

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TC

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WF WF

Location schematics for heaters & thermocouples grouped by zone

System Schematic Methodology

1/31/2011 © Acrolab 201145

THERMOCOUPLE

CONNECTORMULTI-PIN

PIN

NU

MB

ER

ZO

NE N

UM

BER

PIN

NU

MB

ER

TER

MIN

AL N

UM

BER

POWERMULTI-PIN

CONNECTOR

TOTAL WATTAGE FOR STATIONARY HALF = 36,000W

BCTOTAL AMPS

ZONE 4

CAVITY HALF (STATIONARY)ZONE 1

R

AC

AB

WATTS

ZONE 3ZONE 2 ZONE 5 ZONE 6

TOTAL

(WATTS)

12000

12000

12000

E

ZONE 1

1A

ZONE 1

(ACTIVE)

-CO 210 RED

8 WHITE

RED16

IR

1

RED

WHITE

RED

WHITE

RED

WHITE

RED

WHITE

RED

WHITE

5

14

15

7

6

13

12

4

11

3

+IR5

-CO

IR

CO

+

-

6

CO

IR

-

+

CO

IR

-

+

4

3

WHITE

RED

WHITE1

2

9

+IR

IR

CO

+

- 1

3B8

CO

ZONE 5

(SPARE)

ZONE 3

(SPARE)

ZONE 3

(ACTIVE)

10

CO

ZONE 2

(ACTIVE)

CO

ZONE 1

(SPARE)

IRCO

9

IR

2

CO

ZONE 2

(SPARE)

IR IR CO

3 11

IR

ZONE 4

(SPARE)

IR

ZONE 4

(ACTIVE)

COIR CO

124

ZONE 5

(ACTIVE)

CO IR

5

IRCO

13

IR

ZONE 8

(ACTIVE)

ZONE 6

(SPARE)

14

CO

ZONE 6

(ACTIVE)

IR

6

COIR

ZONE 7

(SPARE)

IR CO

ZONE 7

(ACTIVE)

COIR

19

24IR

ZONE 8

(SPARE)

CO CO

2223

21

20

13

16

1817

1514

11

12

10

9

5A

6A6B6C

5B

5C

4B

4C

4A

3C

ZONE 5

5C

CAVITY HALF (STATIONARY)ZONE 3

3B

ZONE 2

1C1B 2A 2B 2C 3A

ZONE 4

4A3C 4B 5A4C 5B 8A6B6A 6C

ZONE 6

7B7A 7C

ZONE 73

8B5

7

6

8C 4

ZONE 8 2

1

1C

2B

3A

2C

2A

1B1A

ZONE 8ZONE 7

CO

IR

CO

IR +

-

+

-

7

87A

7B

7C8A8B

8C7 15 8 16

1

RE

WATTS WATTS

ER

1500

23.5

11.4

WATTS

ERER

WATTS WATTS

ER

WATTS

ER

WATTS

ER

1500W,230V

Ø5/8 x 15.75"

2

3 6

5

4

9

8

7

12

11

10

15

14

13

18

17

16

21

20

19

24

23

22

DCX 09DS H/L REFL

DCX 09DS H/L REFL

1500W,230V

1500W,230V

1500

1500

Ø5/8 x 15.75"

Ø5/8 x 15.75"

23.5

23.5 23.5

1500

23.5

1500

1500

23.5

23.5

1500

23.5

1500

1500

23.5

23.5

1500

23.5

1500

1500

23.5

23.5

1500

23.5

1500

1500

23.5

23.5

1500

23.5

1500

1500

23.5

23.5

1500

23.5

1500

1500

23.5

23.5

1500

23.5

1500

1500

23.5

11.4 11.4 11.4 11.4 11.4 11.4 11.4

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 13.00"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 13.00"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

Ø5/8 x 15.75"

1500W,230V

1500W,230V

Ø5/8 x 13.00"

1500W,230V

Ø5/8 x 15.75"

Ø5/8 x 15.75"

1500W,230V

1500W,230V

Ø5/8 x 15.75"

1500W,230V

Ø5/8 x 15.75"

Ø5/8 x 15.75"

1500W,230V

1500W,230V

Ø5/8 x 13.00"

Electrical schematics showing wiring connections for heaters and

thermocouples grouped by zone

System Schematic

1/31/2011 © Acrolab 201146

Case Study # 2: Breaker Housing

Subject to confidentiality, specific mold designs, system layouts or detailed molding parameters

will not be presented. The photos above are only a general representation.

1/31/2011 © Acrolab 201147


Square D Corporation molds commercial, industrial andresidential switch gear and electrical breakers.

A six cavity residential breaker housing mold was builtfor operation in a 200T Bucher injection thermoset moldingmachine.

The material being molded was a polyester BMC.Injection thermoset was chosen over a manually loadedvertical press in order to reduce scrap and increaseproduction and part uniformity.

1/31/2011 © Acrolab 201148

This complex mold incorporated slide actions andwas constructed using mold face inserts.

These inserts presented intrinsic thermal gaps at theircontact surfaces. The mold was electrically heated bypositioning cartridge heaters in locations that were asclose as possible to the contact surfaces of the inserts.

When heated, the mold indicated temperaturevariations from random point to point on the workingfaces from 300º F to 350º F, a 50º F delta T. Theresultant cycle time for the mold was unacceptable. Themold part exhibited heat stress and blistering.


1/31/2011 © Acrolab 201149

The mold was modified to accept a matrix ofover 150 heatpipes in various diameters tobridge the inserts with the heater array.

The mold was machined to accept the retrofit bythe mold maker, Artag Plastics Corp of Chicago.The heatpipe matrix and associated componentswere installed.

The mold was then installed in the same pressand operated using the same parameters loadedinto the PLC as in the first instance.


1/31/2011 © Acrolab 201150

Major improvements were noted immediately.

1) The mold face delta T random point to point dropped from 50º F to 10º F.2) The cure time was reduced by 13 seconds.3) The overall cycle time was reduced by 22 – 23%.4) The surface appearance of the housings were improved and now met Square D standards.

As a result of the uniform temperature and rapid energythroughput provided by the heating system, Square D wasable to reduce the process temperature by over 40º F witha corresponding reduction in energy costs.


1/31/2011 © Acrolab 201151

Thank YouAdvanced Heatpipe Energy Transfer Systems

for Thermoset Injection Molds

Joe OuelletteChief Technology Officer

Acrolab Ltd.Advanced Thermal Engineering Research & Development

Products and Services

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Advanced Energy Transfer Systems Thermoset Molding