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Basics of Design I

Basics of Design I

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Basics of Design I

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  1. Basics of Design I

  2. Design For Assembly Integrated Baffle, Oil Pick-Up Tube and Scrapers Mains Integrated baffle is captured and located by lower skirt and cranks mains eliminating the need for fasteners 11 parts Integrated Into one Existing baffle oil pick-up tube w/gasket and fasteners Lower Skirt Oil Pan

  3. Snap-Fit Opportunities • Integrated Snap Fits • No extra part • Simple & reliable • Design freedom

  4. E = Secant Modulus s s s E = [MPa] e s Q s Alpha f F h e 2 h/2 L • s f = 1.09 • L [mm] h Height mm h Width mm b Deflection length mm L Deflection undercut mm f Angle degree Alpha Deflection force Newton Q Engagement force Newton F General case POM High Viscosity 8 PBT 3-4 POM Med. Viscosity 5 GR PBT 0.7-1.5 Approx. values Nylon 6.6 DAM 2-3 GR PET 0.5-0.8 Nylon 6.6 Cond. 4-6 TPC-ET 15-20 for e GR Nylon DAM 0.5-1.2 [%] GR Nylon Cond 0.9-2.0 Snap-Fit Design

  5. Undercut Design • Undercuts rounded to avoid tearing of part & stress concentration. • Ejectors should be large to avoid penetrating the part. • Cycle time (specially hold pressure time) should be optimum to avoid excessive shrinkage. • POM Undercut = ((B-A)/B) £ 5%

  6. Influence of notches on… Impact Strength Break energy in J/m (Izod impact strength)

  7. Sharp Corners

  8. Wall Section Design Non-uniform wall thickness Wall Thickness Design

  9. Force x x L Deflection Beam Case Tensile E-modulus for some materials 210.000 Steel 70.000 Aluminium 19.500 55% GR PET 11.000 30% GR PET 3 B H H 10.000 X 30% GR PBT I = 12 x-x 10.000 30% GR Nylon 6.6 (DAM) 7.500 30% GR Nylon 6.6 (Cond.) B 3.300 Nylon 6.6 (DAM) 3 F L 3.200 POM Med. Viscosity d = 3.100 POM High Viscosity 3 E I 1.600 Nylon 6.6 (Cond.) x-x

  10. Profile Stiffness Moment of 6.0 A Inertia for A, B and C 3 140 2520 mm 4.0 9.2 B Compared to A material savings up to 22.9 % 2.8 28 2.0 11.2 C Compared to A material savings up to 57.4 % 1.8

  11. Deformations with a Constant Load Force No deformation Profile 1, deformation 1 Profile 2, deformation 2 W H t H, W, t = constant 1.00 0.62 0.48 0.44 0.57 0.46 1.12 0.33 Relative deformation value versus the reference profile Reference

  12. Relative Torsion Stiffness Reference 10.5 28 14 30 1.0 1.5 13.5 27.3

  13. Rib Designs Rib & Sink Marks Alternative to ribs

  14. Ten rules for designers • Aim for uniform wall thickness. • Design wall thickness as thin as possible and only as thick as necessary. • Use ribbing instead of greater wall thickness. • Provide radiusing. • Provide demoulding tapers. • Avoid undercuts. • Do not design to greater precision than required. • Design multi-functional components. • Use economic assembly techniques. • Gate moulding on the thickest wall.

  15. A Polymer for Every Application