1.
Application of vacuum-assisted high-pressure RTM-process for the series production of CFRP components for car bodies

2. Schuler SMG – the company
Schuler SMG is part of the Schuler Group
The Schuler Group is the technological and world-market leader in forming technology
Schuler SMG is a system supplier for hydraulic presses and press lines with the brands SMG, Hydrap and Müller Weingarten
Employees Schuler SMG 2011/12: 666, of which 49 are apprentices

3. Overview of presentation
Motivation for the use of CFRP parts in the automotive industry
The vacuum-assisted high pressure RTM press process
Press technology for the high pressure RTM process with example of supplied presses 36,000 kN – 3.6 x 2.4 m
System overview of complete RTM process
New development of press technology

4. Light weight design in the automotive industry - Motivation
Future of mobility
Energy costs will rise
Fuel consumption and emmissions will be increasingly financially punished.
Laws concerning emissions influence mobility (E- mobility, etc.)
For development of new vehicles there is a challenge of balancing safety, efficiency (environment) and joy of driving
car
Joy of driving
Efficiency (environment)
Safety
Vehicle concept
Component function
Choice of material

5. Light weight design in the automotive industry - Potential
Potential of various materials with regard to light weight design
Steel
Aluminum
Quasi-isotropic
CFRP
unidirectional
CFRP
Source: Audi AG

6. Overview of presentation
Motivation for the use of CFRP parts in automotive industry
The vacuum-assisted high pressure RTM press process
Press technology for the high pressure RTM process with example of supplied presses 36,000 kN – 3.6 x 2.4 m
System overview of complete RTM process
New development of press technology

7. Press processes for fiber reinforced plastic
Thermosetting plastics
Thermoplastics
Long fibers < 50 mm
arbitrary fiber
SMC / D-SMC
GMT / LFT / LFT-D
Endless fibers > 50 mm
Dedicated fiber orientation
RTM / HP-RTM
Organic sheet
e.g. deck lid, bumper…
e.g. spare wheel well, front end…
Organoblech: Opel Sitzschale
SMC: Daimler CLK Heckklappe
RTM: i3 Fahrgastzelle
e.g. passenger cell, roof…
e.g. seat shell, front end…
Source: BMW and BASF

8. The vacuum assisted high pressure RTM press process
Preform placement
Press closing, start apply vacuum
Resin injection, with position control
Curing with compression force
max. 80 bar slide position +/ mm force up to kN
Force up to kN

9. The vacuum assisted high pressure RTM press process
Mold opening
Press opening
Unload part
Mold cleaning
Mold break open force
Up to kN

10. Overview of presentation
Motivation for the use of CFRP parts in automotive industry
The vacuum-assisted high pressure RTM press process
Press technology for the high pressure RTM process with example of supplied presses 36,000 kN – 3.6 x 2.4 m
System overview of complete RTM process
New development of press technology

11. CFRP sample parts produced on Schuler presses
BMW i3 – passenger cell
BMW M3 – roof

12. Requirements for the RTM press
Uniform wall thickness of the pressed part
Maintaining of resin injection position for gap-injection
Minimizing of non-productive time for mold cleaning / handling
Smooth mold opening
Reliable media supply to the molds
Short pressure build-up and efficient energy use

13. Requirements for the RTM press
Uniform wall thickness of the pressed part
Press statics with congruent bending lines of slide and table
Parallelism of slide to table also at high eccentric load

14. Press design with congruent bending lines
Traditional design
Raising deviation of bending lines
Wall thickness non-uniform
Uniform wall thickness

15. Press design with congruent bending lines
FEM optimized slide
Congruent bending lines lead to a flat slide construction

16. Requirements for the RTM press
Uniform wall thickness of the pressed part
Press statics with congruent bending lines of slide and table
Parallelism of slide to table also at high eccentric load

17. Hydraulic slide parallelism control
Eccentric load for the slide results from the process
Non-symmetric part geometry = eccentric center of force load
The liquid / pasty-like resin compound flows arbitrarily, when closing the mold
Press frame
Counter-acting parallelism control cylinders
Mold
Center of force load

18. Hydraulic slide parallelism control
Four counter-acting cylinders
Each cylinder max. 2,000 kN / max. moment 8,000 / 4,000 kNm
Achievable parallelism: 0.05 mm absolute at 0.5 mm/s
Adjusting spindle for adaption of different mold heights (between 1,200 – 1,800 mm)
Parallelism cylinder with integrated position encoder

19. Requirements for the RTM press
Uniform wall thickness of the pressed part
Maintaining of resin injection position for gap-injection
Minimizing of non-productive time for mold cleaning / handling
Smooth mold opening
Reliable media supply to the molds
Short pressure build-up and efficient energy use

20. Maintaining injection position of the slide
Resin injection
with slide position +/ mm
Task:
Maintaining of injection position against rising internal resin pressure and rising eccentrical load.
F at injection up to kN
Solution:
Closed-loop control for position + parallelism with set value position of parallelism cylinders and actuating value slide force
Cavity pressure
max. 80 bar

21. Requirements for the RTM press
Uniform wall thickness of the pressed part
Maintaining of resin injection position for gap-injection
Minimizing of non-productive time for mold cleaning / handling
Smooth mold opening
Reliable media supply to the molds
Short pressure build-up and efficient energy use

22. free position for bolster 2
Design with 2 moving bolsters
Two lower molds and one shared upper mold
Part loading and unloading during the secondary processing time
Cleaning of the lower mold during the secondary processing time
moving bolster 1
moving bolster 2
free position for bolster 2

23. Telescopic cover for the bolster trench
Design with two moving bolsters
Telescopic cover for the bolster trench

24. Requirements for the RTM press
Uniform wall thickness of the pressed part
Maintaining of resin injection position for gap-injection
Minimizing of non-productive time for mold cleaning / handling
Smooth mold opening
Reliable media supply to the molds
Short pressure build-up and efficient energy use

25. Smooth mold opening through parallelism control cylinders
Break-open of glued molds
Mold break open force up to kN
Moving bolster locking device
Die clamps
Example: turn-pull die clamps in slide and bolster
Lock-pockets in the moving bolster
Locking bolts in the lateral upright

26. Requirements for the RTM press
Uniform wall thickness of the pressed part
Maintaining of resin injection position for gap-injection
Minimizing of non-productive time for mold cleaning / handling
Smooth mold opening
Reliable media supply to the molds
Short pressure build-up and efficient energy use

27. Reliable media supply of molds
Detail view media supply of upper mold
automatic multi-couplings

28. Requirements for the RTM press
Uniform wall thickness of the pressed part
Maintaining of resin injection position for gap-injection
Minimizing of non-productive time for mold cleaning / handling
Smooth mold opening
Reliable media supply to the molds
Short pressure build-up and efficient energy use

29. Short pressure build-up time and efficient energy use
Accumulator drives
Charging pumps continuously charge with low power
Temporarily a high volume flow with nominal pressure is available for a working speed of 30 mm/s at kN
Charging pump units 2 x 55 kW Noise < 75 dB(A)

30. Overview of presentation
Motivation for the use of CFRP parts in automotive industry
The vacuum-assisted high pressure RTM press process
Press technology for the high pressure RTM process with example of supplied presses 36,000 kN – 3.6 x 2.4 m
System overview of complete RTM process
New development of press technology

31. System overview complete HP-RTM process
From carbon fiber mats to a finished part
HP-RTM
Preforming
Handling
Stack production
Material magazine
Handling
Trimming of finished part
Heating
Trimming of Fiber mats
Mixture and dosage technology
Trimming of preform

32. System overview complete HP-RTM process
Technology partners Schuler and Frimo
Provision of garments
Production of preform
Trimming of preform
Handling of preform
RTM- press
RTM-mold
Mixing / Dosage technology
Handling of cured part
Machining of cured part

33. Overview of presentation
Motivation for the use of CFRP parts in automotive industry
The vacuum-assisted high pressure RTM press process
Press technology for the high pressure RTM process with example of supplied presses 36,000 kN – 3.6 x 2.4 m
System overview of complete RTM process
New development of press technology

34. Short stroke press – Function principle
Short stroke press – Function principle 1 2 3 4
slide
mold
press plate
- Slide starts moving downwards (parallelism controlled)
- Slide reached working position
- Slide is locked by split nuts
- Press plate starts movement upwards (parallelism controlled)
- Working stroke with press plate from bottom

35. Two central positioned cylinders Four edge-positioned cylinders
Short stroke press – Parallelism control
Individual setting of press force between cylinders
Parallelism control integrated
Bending line of press table can be influenced
Congruent bending lines of press table and slide
Two central positioned cylinders
Four edge-positioned cylinders

36. Short stroke press – Technical innovation
Reduction of machine height
Easy accessibility
Integrated parallelism control
Short pressure build up time
Reduced energy consumption

37. We are looking forward to your visit at our booth
Thank you very much
for your attention
We are looking forward to your visit at our booth