1. CONFIDENTIAL Silk metal cover concepts Silk/ Nokia Uni-body

2. CONFIDENTIAL 31/08/2010Pauli Havukainen2 Uni-Body Sheet Metal Concept proposal V1 Inside welded concept –A-Cover_Bezel_Front SUS304 Annealed T=0.8 mm Punching, machining –A-Cover_Frame SUS304 Annealed T=0.8 mm Drawing, stamping, machining –Battery_cover SUS304 Annealed T=0.8 mm Stamping ”Hairline” gap ( < 0.06 ) in sharp corners are occured Welding can be done as dot or as continuos welding Boths ends and side key holes are machined after welding

3. CONFIDENTIAL 31/08/2010Pauli Havukainen3 Uni-Body Sheet Metal Concept proposal V2 ( Recommended ) Seamless welded concept –A-Cover_Frame SUS304 Annealed T=0.6 mm Drawing, stamping, machining –Battery_cover SUS304 Annealed T=0.6 mm Stamping Outer radius ( = material thickness ) has to be accepted –Variable radius might be needed to use due angle variation to reach uniform flat region around window. Seamless welding has to be polished –Smooth radius (>R2 ) is needed to accept Boths ends and side key holes are machined after welding

4. CONFIDENTIAL 31/08/2010Pauli Havukainen4 Uni-Body Sheet Metal Concept V3 ( Not recommended ) Seamless welded concept –A-Cover_Frame SUS304 Annealed T=1.0 mm Drawing, stamping, machining –Battery_cover SUS304 Annealed T=1.0 mm Stamping Not enough material for complete shape in machined solution Seamless welding has to be polished –Smooth radius is needed to accept HIGH RISK: Huge dimensional variation is expected due too small angle between surfaces –5° => α > 30° should be used to enable this solution Boths ends and side key holes are machined after welding α

5. CONFIDENTIAL 31/08/2010Pauli Havukainen5 Uni-Body Sheet Metal Concept proposal details/ options Seamless welded concept –A-Cover_Frame SUS304 Annealed T=0.6 mm Drawing, stamping, machining –Battery_cover SUS304 Annealed T=0.6 mm Stamping –MIM / Sheet_metal parts, 3 pcs, laser welded to Frame Consider welding thicknesses ( 0.5*T_A-Frame –MIM parts, 2 pcs, laser welded to Frame Consider welding thicknesses ( 0.5*T_A- Frame ) –Laser welded sheet metal stiffeners can be used at both ends Stiffener thickness 0.5*T_A-Frame

6. CONFIDENTIAL 31/08/2010Pauli Havukainen6 Uni-Body Forged A-Frame concept Seamless welded concept –Forged A-Cover_Frame SUS304 Annealed, SUS316L T=0.6 mm Forging, stamping, machining –Stamped Battery_cover SUS304 Annealed T=0.6 mm Stamping –MIM / Sheet_metal parts, 3 pcs, laser welded to Frame Consider welding thicknesses ( 0.5*T_A- Frame –MIM parts, 2 pcs, laser welded to Frame Consider welding thicknesses ( 0.5*T_A-Frame ) Magnetic permeability after forging need to be considered in material selection.

7. CONFIDENTIAL 31/08/2010Pauli Havukainen7 Uni-Body Forged A-Frame concept V1 Outer radius ( around R0.3 mm ) has to be accepted after forging. –Variable radius might be needed to use due angle variation to reach uniform flat region around window. Seamless welding has to be polished –Smooth radius is needed to accept –Radius >R2 is feasible for instance Boths ends and side key holes are machined after welding

8. CONFIDENTIAL 31/08/2010Pauli Havukainen8 Uni-Body Forged A-Frame concept V2 ( Not recommended and very risky ) High speed CNC milling is one option to reach sharp edge –Width tolerance on sides will be around +/- 0.1 mm –Width tolerance at ends will be around +/- 0.5 mm due so small angle differences between surfaces α

9. CONFIDENTIAL 31/08/2010Pauli Havukainen9 Milling issue at both ends Forged surface Machined surface Nominal edge position

10. CONFIDENTIAL 31/08/2010Pauli Havukainen10 Milling issue detail: Effect of Z variation to Y Forged surface Machined surface Nominal edge position 0.01 0.1275 Blue line = forged surface before machining Z Y

11. CONFIDENTIAL 31/08/2010Pauli Havukainen11 General questions General mechanics  LOM design feedback for Forged Unibody concept?  On pages 5, 6, 7, 8  What is maximum feasible hardness for Sheet metal unibody concept?  Annealed is recommended due best dimensional control  Annealed for A-Frame and 1/2H for Battery cover can be used as well.  Can lower&upper sheet metals be different thickness for laser welding?  Could be. Not recommended due welding jig is more complex to push parts correctly together  In case of inside welding not recommended either. Corner weld is needed instead of straight seam.  Is it a problem to do laser welding for Forged upper parts & sheet metal lower part?  No. Both are same stainless steel alloy. Welding areas have been machined or stamped accurately  If using sheet metal upper part, is it possible to weld 2 nd metal piece behind thin “bridges” to support them? (weak sheet metal bridges biggest reason for forged option)  Forged option has 0.8 mm thick sheet in model. Same thickness can be used also in sheet metal solution.  LOM small radius sheet metal: add estimation for these radiuses  Variable radiuses might be needed to use due angle differences.  Outer radius can be equal to material thickness ( polishing might increase it a little )  Outer radius >R2.0 is recommended for seamless welded region. Bigger radius is more feasible to finish by polishing. Yield will be better also.