Light RTM (LRTM) Moulding “Mould build technology"

1. Light RTM (LRTM) Moulding

“Mould build technology"
Presented By
Alan Harper, Managing Director, Plastech TT. UK.
Plastech TT Ltd.,
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2. Master Model

Orientation
Flange
Surface
Draft
angle
Release agent
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3. Master Model Orientation

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4. Lounger pattern Flange

Dual level flanging
Simple flange
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5. Flange/seal rules

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6. Primary and secondary seals may follow different paths

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7. Corner radii restriction must be observed

Seals
placed on
pattern to
simulate
paths
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8. Other Flange examples

130 mm +/- 5mm
Flange direction
change
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9. Master Model -Pinch off detail

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10. Inserts in the first mould flange

Flange
vacuum
Injection port
Alternatives
Autosprue
10mm pipe
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11. Location of inserts on master pattern

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12. Injection port on Face tool

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13. Inserts illustrated

Flange vacuum
insert
Autosprue
insert
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14. General mould cross section

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15. Typical VM mould production set up

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16. Location - Dowelling

X
and y location
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17. Peripheral Fill

Resin
mould flow designed to find initial
easy path around cavity.
Ideal - path fills before cavity starts to fill.
Theory to practise example………
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18. Flow path built into Mould flange

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20. 4m² small craft VM mould - filling

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21. Reality

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22. More Flow shots

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23. Face tool Lay up

Release
agent
Tooling gel coat VE
Tissue + VE
First layer 450 g/m² CSM + VE
Second 3 x 450 g/m² CSM + LP
Frame – wood or light steel
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24. Calibration of first mould

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25. Seals and flow channel profiles

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26. Seals and profiles

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27. Resin Runner Profile

In face
mould
or
contra
mould
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28. Resin runner position

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29. Two vacuum levels

Vacuum
1 to clamp mould flange.
At least 85% providing 1 tonne/linear m.
Vacuum 2 to clamp cavity and assist fill.
55% provides 0.55kg/cm ² clamping.
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30. Air driven vacuum control

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31. Accuracy is the Key – Vacuum lock during LRTM Mould build

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32. Total Cost of moulds

Mould material costs £340 / m²
Labour costs average 30 hrs /m²
Comparison, LRTM tooling is less than
50% the cost of conventional RTM
tooling
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33. High Volume VM up to 800/ day!

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34. VM will mould Small to Large Parts

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35. LRTM can go big and complicated

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36. Wind Turbine housing – approx. 100 m2 surface area

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Difference between RTM and LRTM
Moulding Speed
Moulding accuracy
Equipment requirements
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39. “RTM” and complimentary “LRTM” closed moulding for composites

Difference between RTM and LRTM
Moulding Speed
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40. Moulding Speed

LRTM
injects the fibre pack at
approximately 1/3 the speed of RTM
LRTM cannot be speeded up by using
higher injection pressure
RTM is able to inject 2 to 4 times faster
Optimised RTM 6 times faster
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41. “RTM” and complimentary “LRTM” closed moulding for composites

Difference between RTM and LRTM
Moulding Speed
Moulding accuracy
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42. Moulding Accuracy

moulds within +/- 0.025”at best
RTM moulds within +/- 0.002” at best
LRTM mould accuracy governed by fibre
pack and vacuum level- unpredictable
RTM mould set accuracy controlled by
design - predictable
LRTM
Plastech TT Ltd.,
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43. “RTM” and complimentary “LRTM” closed moulding for composites

Difference between RTM and LRTM
Moulding Speed
Moulding accuracy
Equipment requirements
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44. Equipment requirements

RTM
needs a low pressure meter mix
machine and tool manipulator.
LRTM needs a VERY low pressure meter
mix machine and two vacuum sources
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45. Low pressure LRTM Machine

Mould
Pressure
Guard
Regulates
speed of
pump to
achieve safe
low pressure
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46. More Application examples

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47. Sunlounger

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48. Pacific Composites - Australia

Pacific
Composites Australia
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49. Invalid Bath

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50. 10mm thick 80kg VE resin

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53. VM can go big and complicated

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56. Other VM applications

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57. Conclusions

LRTM
is a viable lower cost system
complimentary to RTM.
Tooling manufacture must be accurate
Material selection, resin, fibre critical.
Operating procedures must be
consistent for success.
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58. Heating /Temperature control

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Electrical Heater-Cloth Application.
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