creating a future for engineers formula student germany wet laminated cfrp monocoque manuel baumann...
TRANSCRIPT
Creating a Future for Engineers
Formula Student Germany
Wet laminated CFRP monocoque
Manuel Baumann amz.ethz.ch
Creating a Future for Engineers
Introduction
Creating a Future for Engineers
Mold manufacturing
Part manufacturing
Additions
Potential
Bill of Material
Timeline
Index
Creating a Future for Engineers
Positive molds
Laminated negativ molds
Wet laminated monocoque
Bonded halves
Mold manufacturing – Concept
Creating a Future for Engineers
Mold manufacturing – Molding material
MDF PU Aeroboard 70
Density 800 kg/m ³ 630 kg/m ³
Thermal expansion 7.5*10-6 46.8*10-6
Thermal resistance >100° 93°
Cost 500 EUR/m³ 8000 EUR/m³
Disadvantage MDF
Inhomogeneous density over thickness
Sensitive to humidity
Creating a Future for Engineers
Mold manufacturing – Positive molds Bonding
Creating a Future for Engineers
Mold manufacturing – Positive molds Milling
Creating a Future for Engineers
Mold manufacturing – Positive molds Sanding
Creating a Future for Engineers
Mold manufacturing – Positive molds Priming
Creating a Future for Engineers
Mold manufacturing – Positive molds Bolts for insert positioning
Internal thread
Creating a Future for Engineers
Material choice: CFRP
Alternative material: GFK
Mold manufacturing – Negative molds
Creating a Future for Engineers
Formenharz P
Mold manufacturing – Negative molds
Creating a Future for Engineers
Formenharz P
Connection layer:
Epoxy
Fibreglas
Flocs
Thixotropiermittel
Mold manufacturing – Negative molds
Creating a Future for Engineers
Formenharz P
Connection layer
6 Layers carbon fibre
600 gr/m²
Mold manufacturing – Negative molds
Creating a Future for Engineers
Formenharz P
Connection layer
6 Layers carbon fibre
Vacuum
Mold manufacturing – Negative molds
Creating a Future for Engineers
Formenharz P
Connection layer
6 Layers carbon fibre
Vacuum
Demoldi
Mold manufacturing – Negative molds
Creating a Future for Engineers
Formenharz P
Connection Layer
6 Layers Carbon Fibre
Vacuum
Demold
Finished mold
Mold manufacturing – Negative molds
Creating a Future for Engineers
Core material:
Divinycell HP 60 foam
Insert material
Carbon and wood
Part Manufacturing – Material choice
Creating a Future for Engineers
2 core layers of 5mm
Heat bending
Part manufacturing – Monocoque halves
Creating a Future for Engineers
2 core layers of 5mm
Heat bending
Vacuum bonding
Sanding
Part manufacturing – Monocoque halves
Creating a Future for Engineers
Mold release agent
Frecote
Part manufacturing – Monocoque halves
Creating a Future for Engineers
Mold release agent
Frecote
Resin: Hexion L 235
Hardener L236
Microballons for filling the gaps
Part manufacturing – Monocoque halves
Creating a Future for Engineers
Procedure
4 layers CFRP
Placing core / inserts
12 h vacuum
4 inner layers CFRP
15 h vacuum
12-20 h curing at 80°
Part manufacturing – Monocoque halves
Creating a Future for Engineers
Bonding
the halves
Part manufacturing – Joining upper and lower halves
Creating a Future for Engineers
Roll hoop
Part manufacturing – Additional structural parts
Creating a Future for Engineers
Roll hoop
Rib
Part manufacturing – Additional structural parts
Creating a Future for Engineers
Weight: 21kg (without rollhoops)
Part manufacturing – Result
Creating a Future for Engineers
Painting
Degreasing
Primer
Sanding
White color
Sanding
White color
Clear varnish
4kg
Part manufacturing – Additional structural parts
Creating a Future for Engineers
Prepreg Monocoque: -Temperature resistant resin for negative molds
-Same manufacturing process
Advantage: Less weight, better surface, no painting needed
Additions – Potential
Creating a Future for Engineers
Additions – Bill of material
Material Amount Price
CFRP 600g/m2 for negative molds 30m2 1200EUR
CFRP 250g/m2 for monocoque 40m2 1400EUR
Foam Core 5mm 6m2 300EUR
MDF 0.8m3 500EUR
Resin 35kg 600EUR
Vacuum material 300EUR
Total 4300EUR
Creating a Future for Engineers
Important:
Well organiced workspace for laminating and sanding
2-4 people needed during laminating (due to little pot-life)
We used 8 weeks, mostly one person for positive molds, negative molds and monocoque
Additions – Timeline
Creating a Future for Engineers
05. – 09. August 2009
See you at Hockenheim