• Walls in any plastic-molded part should be no less than 40 to 60 percent that of adjacent walls, and all should fit within recommended thickness ranges for the selected material.
• Part geometries such as long unsupported spans, sharp internal corners, and poorly designed bosses (not the person in the corner office who signs paychecks), should be avoided, regardless of wall thickness.
• Use ribs for strengthening tall walls where needed.
• Sharp external corners are fine, but placing a radius on inside corners—part design permitting—makes them stronger and alleviates the stress that creates warp.
• Bosses should follow molding design guideline rules of properly designed walls of 40-60 percent of the surrounding area to avoid sink.
• Finally, follow recommendations on draft angles—1 degree of draft per 1 inch of cavity depth is a good rule of thumb—and keep draft consistent throughout the workpiece to prevent internal stresses that lead to warp and curl.

Choose Materials with Wall Thickness 

One of the biggest considerations with wall thickness is which material to use for your project. With literally hundreds of materials to choose from, deciding on the right one can be challenging. You can view available resins grouped by family with recommended wall thickness ranges along with detailed information on material properties, tensile and impact strength, and maximum operating temperatures online.
Here is the materials :