Rational Systems - Plastic & Machining Products

21 www.rational-sys.com 5. Grooves and Slots: 5. Undercuts: 4. Bosses & inserts: Orient grooves and slots in the flow direction to minimize air entrapments Make sure grooves and slots are rounded or chamfered rather than sharp to help flow and vent air Consider positioning slots in a side wall curled around the base plane to allow for molding without slides If possible, avoid undercuts. Undercuts can be molded but may be costly and only possible in localized areas Attach bosses to the side walls of the part to allow air to escape during the molding process Avoid isolated bosses When design bosses that are not attached to a side wall, use gussets or vent the boss with a core All bosses need radii at their bases Threaded inserts can be either post mold or molded in the part The insert design, hole diameter, part density and screw size determine the pullout force and stripping torque of threaded inserts