1. Mould tools
John Summerscales

2. Outline of lecture Tool design Tool materials Decision matrix
Heating and cooling
Lost cores
Clamping
Ancillary materials and systems

3. Tool design size, complexity and dimensional tolerances surface finish
thermal expansion, conductivity etc
holes, bosses and ribs
inserts and fasteners
re-entrants/multi-part moulds
number of components to be produced
durability, ease of modification and repairability

4. Tool materials Reductive manufacture (CNC machining)
steel
aluminium
monolithic graphite
syntactic foam (hollow microsphere composite)
Additive manufacture
wet lay-up glass reinforced plastics
prepreg carbon fibre composite
electroform nickel (EFN)
backing structures
Plastech MITTM Multiple Insert Tooling

5. Pre-preg/EFN tooling master splash tool
HT male mandrel/bath master LTM tooling system omits this stage
Female tool
LTM tooling system omits this stage
Tool with backing structure

6. Decision matrix: tooling options
Nicholas Tiffin, "Choosing better tooling", Advanced Composites Engineering, Autumn 1988, 18/19.
Note that the following analysis from Tiffin's paper is specific to a CFRP structural fairing
P = Priority
R = Rating
V = Value (P*R)

7. Decision matrix: tooling options
Steel Al
Wet Lay Up
Prepreg
EF Nickel
Critical parameter P R V
Dimensional accuracy 10 7 70 6 60 8 80
100
Operating temperature 9 90
Temperature uniformity 4 36 5 45 63
Long tool life 72 1 64
Short cure cycle 3 18 24 54
Tool build time 30
TOTAL
340
337
329
452
418

8. Tracking barcodes or RFID inserts may be attached to mould tools
to permit integration,
e.g. with resin delivery systems,
and automation.

9. Heating Cooling fluid in pipes embedded electrical heaters
ovens and autoclaves
Cooling

10. Embedded heaters 1 Thermion fabric Gorix ECT
Plastech cotton/lycra heater cloth

11. Embedded heaters 2
PPM Solutions
Plastech copper piping

12. Heating performance
Comparison of cure cycle for 11 mm laminate on heated tool and in oven. The two temperature traces in each case are for the opposed laminate faces
heated tool
oven

13. Simulated temperature distribution
Steady-state temperature distribution over tool (below) and laminate (above), for fixed heater temperature of 130°C
Model = ¼ flat tool (symmetric).

14. Thermographic monitoring
Infrared camera image of an electrically-heated tool-plate
showing hot spots due to wrinkled heater cloth

15. Thermogram of electrically-heated mould tool 1
tool face during heat-up showing cool spots/lines corresponding to the thermocouple positions/wires and cooler outline at the resin-rich mould cavity lip

16. Thermogram of electrically-heated mould tool 2
tool face at target temperature of 90°C showing ~10°C variation across the component

17. Thermogram of electrically-heated mould tool 3
insulated back surface during dwell at 90°C

18. Thermogram of electrically-heated mould tool 4
tool back face (GRP side) without insulation showing the resistive heater element spacing (horizontal shading)

19. Lost cores rubber/elastomers [Musch and Bishop]
inflatable mandrels [Musch and Bishop]
low melting point alloys [Haines]
candle or paraffin wax (melting points typically 50-90ºC)
soluble salts or plaster (subsequently washed or machined out)
Plastech SmartCore (granules enclosed in a shaped vacuum bag)

20. Clamping bolts hydraulic press vacuum labour intensive, low pressure
capital equipment, good alignment
vacuum
inexpensive, limit ~1000 mbar, sealing issues

21. Ancillary materials and systems
mould release (coatings and films)
bagging films (1-sided moulds)
breather and bleeder cloths (vacuum bag)
flow media (infusion)
tacky tape - edge dams - breach units
pressure intensifiers
preforming supports

22. Acknowledgements
the respective companies for illustrations of the embedded heaters
Dr Stephen Grove for the performance graph and simulation
Dave Nelson of FLIR Systems Limited for wrinkled heater cloth thermograms
Scott Foster of Metrum Information Storage Limited for skeg thermograms