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 MDFPU Aeroboard 70 Density800 kg/m ³ 630 kg/m ³ Thermal expansion7.5* *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  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 MaterialAmountPrice CFRP 600g/m 2 for negative molds30m EUR CFRP 250g/m 2 for monocoque40m EUR Foam Core 5mm6m 2 300EUR MDF0.8m 3 500EUR Resin35kg600EUR Vacuum material300EUR Total4300EUR

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