Plastic product design
Q1- Your company is bidding on a new wheel cover as a GM Tier 1 supplier. The part has a diameter of 300 mm and thickness of 3mm and is made of ABS plastic. The quantity required is 100,000 per month. Describe your tooling plan offering. You can use hypothetical injection molding machine specs, or preferably specs from actual machines from your work or the internet.
Describe the trade-offs in different molding plans and why you chose the plan you did. (15 pts.)Useful data: ABS power law viscosity, k, 1.71e4 Pa-s, and a power law index, n, of 0.348.
Q2- 11. Your company wants to produce a baby stroller with a snap-fit cap as in the attached picture to retain the wheels. The desired material is ABS with a flex modulus of 2280 MPa. The cap is 60 mm in diameter and has walls 2.5 mm wide.
There are two retaining snaps that are curved (crowned) cantilever beams with constant cross section which are 50 mm long and 40 mm wide and are curved to match the cap’s outer diameter. The snaps must deflect 6.24 mm to engage.
The lead in angle is 30 degrees and the coefficient of friction, µ, is 0.5. How much force deflection force will the snaps retain and how much will be required to push it on? Report the value in pounds. Note for stiffness factor h=6.24 mm, extrapolate the appropriate curve.(15 pts.
