Press Consolidation/ Thermoforming: Properties and Applications

1. Co-funded by the
European Union
Press Consolidation / Thermoforming:
Properties and Applications
Justine Beauson, Stergios Goutianos (DTU)
Hans Knudsen (COMFIL)
Laurens Van Audenaerde (SAMSONITE)
Silvia Pavlidou (MIRTEC)

2. Introduction
 In the Bio4self project, 2
manufacturing routes to
produce self-reinforced PLA
composite were investigated:
injection moulding and
thermoforming
 The application aimed for
thermoforming manufacturing
are suitcases. The industrial
partner COMFIL produces
organo-sheet (pre-consolidated
sheet) from the PLA fabrics,
which are then thermoformed
by Samsonite to produce
suitcases.
Now looking at the composite level…

3. Content
1. Objectives for thermoforming manufacturing in Bio4self
2. Development work
3. Properties of self reinforced PLA composite
4. Lifetime prediction
5. Potential other applications

4. 1. Objectives for thermoforming manufacturing
Thermoformed suitcase by Samsonite
• Small suitcase - Firelite SP55
• Large suitcase - Cosmolite SP75
Requirements:
• Low weight – Density < 1500 g/m2
• Stiffness / Tensile modulus ≥ 3.2 GPa
• Impact properties: Passing the Samsonite
suitcase test serie

5. 2. Development work
 Description of manufacturing route,
 Setting the right processing conditions,
 Adjustment of other parameters

6. 2. Development work
Description of the manufacturing route
Organosheet correspond to pre-
consolidated fabric plates. Plane plates are
then used in thermoforming.
Organosheet by COMFIL
 Thickness: From 0.5 mm to app. 5mm
 Length: 
 Width: depending on the quantity, up to
650mm
 One off (or a few) can be made in 1200 x
800 x 200 mm

7. 2. Development work
Description of the manufacturing route

8. 2. Development work
Setting the right processing conditions
Manufacturing challenge
 Consolidation temperature: Both of the PLA filament (matrix and reinforcement)
can melt, therefore the processing temperature Tprocess should be carefully
adjusted in order not to melt the reinforcement.
Tm,1 < Tprocess < Tm,2

9. In order to find this temperature, trials were performed.
 Melting temperature of low Tm PLA / matrix material: 155C
 Melting temperature of high Tm PLA / reinforcement: 177C
Plan:
• Manufacture UD fiber composite using different consolidation temperature: 155,
160, 165 and 170C
• Characterize the materials and determine the best processing conditions.
Tm,1 < Tprocess < Tm,2
2. Development work
Setting the right processing conditions

10. Manufacturing at DTU
Filament winding
 Unidirectional fibre composite – 2 mm thick
 Drying overnight in vacuum chamber at
35C
Press consolidation
 Heating: 10 min at selected temperature
under vacuum
 Pressing : 1 min at 30C - Pressure: 2 MPa
2. Development work
Setting the right processing conditions

11. Characterization – Microstructure
 160°C, 165°C and 170°C => microstructure look very similar.
 Few dry areas, no porosities or cracks, good quality overall
160°C 170°C165°C
300 μm
2. Development work
Setting the right processing conditions

12.  155°C microstructre looks very different: porosities, unproper melting of the matrix fibres
 Poor interface properties
155°C
300 μm
165°C
2. Development work
Setting the right processing conditions

13. 2. Development work
Setting the right processing conditions
OK Temperatures
Too high Temperatures

14. Consolidation
temperature
Stiffness Strength
[˚C] [GPa] [MPa]
155˚C 6.3 ± 0.1 104 ± 5
160˚C 5.8 ± 0.2 106 ± 4
165˚C 5.9 ± 0.0 98 ± 2
170˚C 5.8 ± 0.1 84 ± 7
Characterization – Static tensile test 0˚
 E-modulus as expected
 Effect of consolidation temperature on strength properties
2. Development work
Setting the right processing conditions

15. Characterization – Static tensile test off axis
 155°C not performing as well we the other composites in off axis directions
 Indication of poorer interface properties
165C selected
temperature
2. Development work
Setting the right processing conditions

16. Development work related to thermoforming process and suitcase
properties:
 Effect of Number of fabric layer
 Effect of the fabric type and weaving pattern
 Effect of temperature of press consolidation of organo-sheet and
thermoforming
 Effect of PLA matrix material
 …
2. Development work
Adjustment of other parameters

17. Properties of self reinforced PLA composite materials:
Tensile
strength
E-
modulus
Density
[Mpa] [GPa] [g/m2]
UD
composite
113 +/- 3 6.1 +/- 0.1
1341
Fabric
composite
40 +/- 1 3.8 +/- 0.1
3. General properties of PLA
0
1
2
3
4
5
Tensile modulus
[GPa]
PLA self-reinforced composites compared
industrial benchmark:
■ Fabric based PLA composite
■ Curv® self reinforced PP

18. Why it is important..
 Lifetime prediction assessment predicts the long term performance of
the composite materials.
 One of the common drawback of biobased composite materials is
their durability in time, due to their sensitivity to moisture.
 Self-reinforced PLA material developed in the Bio4self project is
stabilized for moisture intake.
4. Lifetime prediction

19. Experimental set up:
 Material is tested to accelerated aging.
 This is performed by exposing the material to 6 different sets of
conditions, which are a combination of temperature and humidity.
 The material is then tested for the most critical property identified by
the end user. For the samsonite case, it was the tensile properties.
 Failure criteria was set to a drop of 20 % in the tensile properties.
4. Lifetime prediction

20. 4. Lifetime prediction

21. 5. Potential other application
Key drivers: lowering the carbon footprint, recyclability, green image of
product.
 Medical devices: implants, orthopedic shoe,…
 Furniture: PLA SRPC has potential as material for structural components
of furniture.
 Automotive: under body shields, interior panels, load floors, scuff plates
and panels for trucks and vans,…
 Industrial equipment: Protection shrouds, Machine cover,…
 Protective (sports) gear: Body armour, Canoes,…

22. Seat structure
 Dimension (in mm): 840 x 470 x 130
 Weight: 600 g
 Manufacturing process: In-mold hybridization.
Thermoforming of consolidated PLA fabrics and
overmolding (rib structures including the overmolding
of metal inserts, which are used as load introduction
elements).
5. Potential other application

23.  Material PLA-PLA fabric (Weave WP1-PLA-400)
 Fabric area weight 420 g/m²
 Planned thickness approx. 1.3 – 1,35 mm (Requirement for Samsonite suitcase SP75)
 4 layers with 1850 x 1050 mm²
 Automated fabric cutting on Zünd cutting table
Automated fabric cutting Manual fabric placement in Fibercon
5. Potential other application

24. IR Heating Contact cooling
Fabric loading between IR transparent
glass ceramics
5. Potential other application

25. Medical device / Orthopedic shoe
5. Potential other application

26. Transport box
 Dimension (in mm): 400 x 300 x 200
 Weight: 400 g
 Manufacturing process: The box consists of a
combination of several plastic intermediates
made via:
 Extruded PLA foam process (inner foamed
structure)
 Thermoforming process (outer layer of
consolidated sheets for protection)
5. Potential other application

27. Automotive part
5. Potential other application

28. Automotive part
5. Potential other application
Layout for thermoplastic composite molding

29. Thank you for your attention!
Any questions?