1) Automated preforming processes can produce complex composite parts in large numbers with lower cycle times and costs compared to existing technologies through techniques like tailored braids, non-crimp fabrics, and automated assembly lines. 2) Key challenges for future composite preforms include developing single-step and multi-step preforming methods to produce parts with locally tailored material properties as well as simulating and designing complex preform geometries. 3) Automated assembly lines show potential for mass production of composites through techniques such as robotic cutting and handling of textiles, quality control, binder application, and novel activation methods.

1. Textile Preforms
V.P.Senthilkumar
11MT71

2. Production Technologies for Composites
 Non-crimp fabrics (NCF)
 Prepregging
 Braids
 3D-preforming
Overbraiding
ITA
NCF machine NCF

3. Strategies for Future Preforming
• Tailored Braids
• Tailored NCFs
• Automated Preform Assembly

4. Preforming technology
The three major challenges for the production of textile preforms
• Reduction of cycle times
• Reduction of costs
• Production of complex parts in large
numbers
BMW I3 car body

5. Motivation for Research in Composites
• Fiber reinforced plastics (FRP) are a promising engineering
material for:
• Aerospace
• Automotive industry
• High-end machine parts
• Wind energy

6. Motivation for Research in Composites
Why FRP for conventional vehicles?
• Emissions: 100 kg car weight ≈ 9 g CO2 per km[2]
• Fuel consumption: 100 kg car weight ≈ 0.4l per 100 km[2]
• Improved safety
• Higher accelerations
Why FRP for electrically driven vehicles?
• Critical distance range
• Expensive batteries
• Integration of functionality
1. Source BMW
2. Source Audi

7. Motivation for Research in Composites
The production of FRP parts in high volume can be realised
by means of Preforming-Liquid Composite Moulding (LCM)
processes
• Short cycle times
• Heavy tow material can be used
• Complex designs
• High amount of manual labour
For composite materials, there is a close interaction
Between
* Production processes
* Part design
* Material properties

8. Future Preforms
WeavingWeaving NCFNCFBraidingBraiding
RovingRoving
Fibre
placement
Fibre
placement
Multi step
preform
Multi step
preform
Preform assemblyPreform assembly3D
Preform
3D
Preform
3D Weaving3D Weaving
3D
Preform
3D
Preform
Single-step
preforming
Multi-step
preforming

9. Strategy For Future Preforms
• Combination of single-step and multi-step preforming
• Single-step: Production tailored textiles with locally adjusted properties
• Multi-step: Automated assembly of tailored textiles into complex preforms
Single-step preforming
(Tailored-NCF)
Tailored-Braid Multi-step preforming
Preforming
Tailored Blank Tailored Tube Assembly line
Source: Thyssen Krupp Source: Thyssen Krupp
Steel
processing
Source: KUKA
Single-step preforming
(Tailored-NCF)
Tailored-Braid Multi-step preforming
Tailored Blank Tailored Tube Assembly line
Source: Thyssen Krupp Source: Thyssen Krupp Source: KUKA

10. Tailored Braids
Process Overview
Roving
(3D Fiber
Weaving) placement
3D sub-
preform
Braiding
Preform
assembly
Multi-step
preform
Warp-
Weaving
knitting
2D
preform

11. Tailored braids
• Overbraiding technology
 Two groups of bobbins moving on concentric circles
 Mandrel is moved through braiding eye
 Tubular braid is laid down on shaped mandrel
Bobbin path in radial braiding
ITA
Radial braiding machine

12. Tailored braids
• Overbraiding technology
 Economic production of near-net shape textile preforms
 0°-layers possible
 Automation possible
 Wide range of materials
Braiding of ceramic fibers Braiding of 0°-layer

13. Tailored braids
• 3D-rotary braiding technology
• Independent bobbin movement
• Highly complex structures
• Fully interlaced structures

14. Tailored braids
Examples for 3D-rotary braids
3D-braided T-profile Preform for crash-absorber with integrated flange
10 mm
Continuous change of cross section 3D-braided branching
16

15. Tailored braids
Challenges braiding technology
• High productivity
• Complex geometries
• No continuous production
if thickness changes
• More possibilities in
production than in
simulation
• Simulation
• Mechanical parameters
• Design tools
• Modification of thickness
• Braiding speed

16. Tailored NCFs
Process Overview
Roving
(3D Fiber
Weaving) placement
3D sub-
preform
Braiding
Preform
assembly
Multi-step
preform
Warp-
Weaving
knitting
2D
preform

17. Tailored NCFs
Multiaxial non-crimp fabrics (NCFs)
0°-Layer supply
Creel for rovings
Production
direction
Take-up
Warp-knitting unit
Computer controlled weft-
insertion-systems
Warp-knittting machine
[LIBA Maschinenfabrik GmbH]

18. Tailored non-crimp fabrics
Production of near-netshaped semi-finished parts in one production process
Non-crimp fabrics (NCF) with
locally adjusted properties
allowing different
• Thickness
• Bending stiffness
• Drapability
Benefits for preforming
• Less cutting operations
• Less cutting waste (up to 60 %)
• Less handling operations
Schematic structure of
multiaxial warp-knit
[LIBA GmbH]

19. Automated preform assembly
WeavingWeaving NCFNCFBraidingBraiding
RovingRoving
Fiber
placement
Fiber
placement
Multi step
preform
Multi step
preform
Preform assemblyPreform assembly3D
Preform
3D
Preform
(3D Weaving)(3D Weaving)
3D
Preform
3D
Preform
Automated

20. Automated preform assembly
Handling
Draping
Handling
Draping
Quality
control
Quality
control
CuttingCutting AssemblingAssembling
preform centre
7 m
5 m

21. Automated preform assembly – step 1: 3-D cutting
 Robotically guided cutting device
 Ultrasonic knife
 Cutting of complex geometries
Robot
Textile
Knife
Housing
Ultrasonic 3D-cutter

22. Automated preform assembly – step 2: handling
 Needle grippers
 Cryo grippers
 Vacuum technology
Needle gripper Cryo gripper Vacuum technology
Pick and place operation at preform centre

23. Automated Preform Assembly – step 3: quality control
Online quality control
 Texture
(material, textile type)
 Orientation and geometry
of textiles
 Defects in textiles
Monitoring head
Lighting
module
Lasersensor
Casing
Camera
Robot flange
Interface
Digital image processing

24. Automated preform assembly – step 4: assembling
Sewing
technology
Sewing
KSL-tufting
Sewing
KSL-blind stitch
Binder
Hot melt

25. Automated Preform
Assembly
Tailored binder application
• Robotically guided
• Local application
• Different binder materials
• Varying binder quantities
Local binder application
Novel binder activation
• Activation by hot air
• Compression of preform
• Robust system with low invest
• Modular system
Novel binder activation device

26. Automated Preform
Assembly
Exemplary process chain for the automated production
of binder-preforms
Loop
cutting handling
Binder
application
Binder
handling
activation

27. Summary
Automated preforming process vs. existing technologies:
 Lower cycle times
 Less waste (down by 60 %)
 Lower costs
 Complex parts in large numbers
→Mass production of composites

28. Properties of some textile performs
Textile
Preform
Advantage Limitation
Low crimp,
uniweave
High in-plane properties; good
taliorability; highly automated
preform fabrication process
Low transverse and out-of-plane
properties; poor fabric stability;
labor intensive ply lay-up
2-D Woven Good in-plane properties; good
drapability; highly automated
perform fabrication process;
integrally woven shapes possible;
suited for large area coverage
and extensive data base
Limited taliorability for off-axis
properties ; low out-of-plane
properties

29. Properties of some textile performs
Textile
Preform
Advantage Limitation
3-D Woven Moderate in-plane and out-of-
plane properties; automated
preform fabrication process and
limited woven shapes are
possible
Limited taliorability for off-axis
properties and poor drapability
2-D Braid Good balance in off-axis
properties; automated preform
fabrication process; well suited
for complex curved shapes; good
drapability
Size limitation due to machine
availability and low out-of-plane
properties

30. Properties of some textile performs
Textile Preform Advantage Limitation
3-D Braid Good balance in in-plane
and out-of-plane properties;
well suited for complex
shapes
Slow preform fabrication
process; size limitation due
to machine availability
Multi-axial warp knit Good taliorability for
balanced in-plane
properties; highly automated
preform fabrication process;
multi-layer high throughput;
material suited for large
area coverage
Low out-of-plane properties
Stitched fabrics Good in-plane properties;
highly automated process;
provides excellent damage
tolerance and out-of-plane
strength and excellent
assembly aid
Small reduction in in-plane
properties; poor accessibility
to complex curved shapes