Download - The Isoplaten -"Thermal Performance of Electrically Heated Platens" - May 2011

Acrolab Ltd.© May 2011

Heated platens are fundamental components in

the molding process of a variety of composites.

Platens provide heat necessary to complete the

molding /curing reaction.

Conventionally heated platens consist of a single

level of heaters housed in a plate.

Acrolab’s Isoplaten® is a bi-level matrix of

heaters and Isobar® heat pipes housed in a metal

plate.

Introduction to Isoplatens®


2

Standard Platen With Heaters

3

Standard

electrically

heated platen

with five

cartridge

heaters and one

thermocouple


Standard Platen With Heaters

4

Electrically

heated

Isoplaten® with

5 cartridge

heaters (yellow)

and 17 Isobars®

(white & red)


Standard platens do not

provide uniform temperature

distribution on the plate

surface.

Temperatures can vary by

up to 25 C along the surface

of the platen.

Non-uniformity can result

in insufficient curing,

increased cycle times,

decreased thermal recovery,

and poor part quality.

Standard Platens

5

Thermogram of a standard electrically

heated platen


Temperature uniformity results in:

1. Decrease in under and over

cured parts

2. Rapid temperature recovery

3. Decreased cycle times

4. Reduced energy consumption

5. Improved overall part quality

Temperature distribution varies

only 2 C across 95% of the

platen.

Isoplatens®

6

Thermogram of an electrically

heated Isoplaten®


“Provide for exceptional temperature uniformity”

Objective:

A comparative analysis of an

electrically heated Isoplaten® vs. a

conventional or standard electrically

heated platen of the same physical

dimensions, the same thermal energy

in-put and with the same load

conditions.

Research Experiment

7


Steady state, loading, boiling/thermal

footprint growth, beginning of recovery,

recovery, complete recovery.

Isoplaten® with 20mL of water in 4” load

container; central loading location (5)

Raw data from “Thermacam Researcher” as

seen during experiment.

Experiment Stages

8Acrolab Ltd.© May 2011

1. To characterize the difference in thermal response between

conventional standard platens and Isoplatens® when subjected to

various thermal loads, at different load positions.

2. A comparative examination of the surface thermal uniformity of

either platen when they are subjected to random cartridge heater

failures.

Standard Platen Isoplaten ®

Overview: Research Experiment


9

Equipment

18” x 18” Isoplaten

IR Camera: FLIR

SC3000

Sampling rate: 1 Hz

Image size: 320 x

180

DAC: Real-time

monitoring

Recording of IR

image sequence

Experiment - Set up


10

Loading Container Loading Positions

Load

Chamber

Configuration common to both platens


11

Phase 1: Comparative dynamic thermal load analysis

a) Steady state

b) Loading

c) Boiling/thermal footprint growth,

d) Beginning of recovery

e) Recovery

f) Complete recovery

Experiment Phases (3)


12

20 mL of water in 4” load chamber; central loading position #5

(both platens)

Load

Chamber

Position# 5


Phase 2 – Position #5

13

Loading at location 5 (center of platen)

T(t)-T0 are plotted during the recovery period

Position #5 - Temperature difference Isotherms


14

Absolute Temperature

Platen Isoplaten

Position #5 - Animated sequences


15

Temperature Difference

Platen Isoplaten



16

1. Steady state

2. Loading

3. Boiling/thermal footprint growth,

4. Beginning of recovery

5. Recovery

6. Complete recovery

Thermographic video sequence


17

Position #5 - Thermal video


18

20 mL of water in 4” load chamber; central loading position #7

(Both platens)

Phase 2 – Position #7

Load

Chamber

Position# 7


19

Absolute Temperature

Platen Isoplaten


The true measured temperature


20

Temperature Difference

IsoplatenPlaten


The temperature difference between the two platens


21

Uniform heat distribution = Quality improvement

Reduction of hot spots in molds = Quality Improvement

Uniform cure rate = Quality Improvement

Improvement of cycle time = Productivity improvement

Reduction of thermal energy required from heaters = Energy Savings

Conventional Platen Acrolab Isoplaten®

Isoplaten:

Conventional platen vs. Isoplaten®


22

Steady-state performance of the Isoplaten is

improved over that of the platen, even with

heater failure.

Recovery time is reduced in all loading modes:

C (θ = 63%) 7 – 26 %

T (within 1 C of SS) 14 – 30 % (or more)

The recovery time is mostly affected by load

position.

23

Summary


The Isoplaten® provides for curing times that

are shorter than the standard platen.

The Isoplaten® provides for a 44-54% faster

curing time over the standard platen.

The Isoplaten® also has a faster recovery

time.

The Isoplaten® will decrease cycle times and

energy consumption.

24

Results


©Acrolab 2011 25

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Advanced Research & Development

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