Which of the following statements are true: High aspect ratio (height/width) features should be aligned with the flow direction of the molten polymer. If threading is needed in an injection molded part, either use an insert, or design it with very fine threads. Blow molding can be used to form both thermoplastic and thermosetting materials. Whenever possible design parts without the need for mechanical sliders or lifters, as they increase the cost of the die significantly. Some injection molded parts do not require a taper, or a slider for internal undercuts, if the material is sufficiently flexible. Injection molding, like metal casting, works better with parts that have uniform wall thickness. Holes should be spaced with a minimum of 1 diameter of solid material between them.