Basics of Design I

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

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

4 L h/2 h f Q F Alpha f = 1.09  s L h 2 [mm] E s = [MPa]  s  s E s = Secant Modulus Snap-Fit Design Height Width Deflection length Deflection undercut Angle Deflection force Engagement force mm degree Newton h b L f Alpha Q F POM High Viscosity8 POM Med. Viscosity5 Nylon 6.6 DAM2-3 Nylon 6.6 Cond.4-6 GR Nylon DAM GR Nylon Cond PBT GR PBT GR PET TPC-ET General case Approx. values for  [%]

5 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% Undercut Design

6 Break energy in J/m (Izod impact strength) V (r = mm) U (r = 3.2 mm) UVUV Nylon Dry as moulded : 1 Nylon Cond. 2.5 % RH : 1 POM : 1 Influence of notches on… Impact Strength

7 Sharp Corners

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

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

Moment of Inertia for A, B and C 2520 mm 3 Compared to A material savings up to 22.9 % Compared to A material savings up to 57.4 % A B C Profile Stiffness

Force W H t H, W, t = constant Profile 1, deformation 1 Profile 2, deformation 2 No deformation Reference Relative deformation value versus the reference profile Deformations with a Constant Load

Reference Relative Torsion Stiffness

13 Rib Designs Rib & Sink MarksAlternative to ribs

14

15  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. Ten rules for designers

A Polymer for Every Application