All About Walls in Product Design

Wall thickness in product design can dramatically alter the amount of materials used and the cooling time of your part after it has been injected into the mould. Ideally, your design will have consistent, reasonably thin walls, which will allow you design to maximise space whilst being efficient, saving you money on both materials and running costs.

  • Thin walls have the dual advantage of using less materials and needing less time to cool. This reduces the overall cycle time needed to create the maximum number of units in the shortest amount of time.
  • Thick walls, as they have a larger volume, use more materials, adding to the cost of manufacture. There is also the danger of inconsistent cooling with thick walls. Inconsistent cooling will lead to sinking and warpage. If your walls are too thick, rejects will be common.
  • Instead of a thick wall many designers will employ ribs. Ribs are supports which are usually set perpendicular to the wall. It is common practice to set a rib’s thickness at 60 percent the thickness of the wall it is supporting. So if a wall is 5mm thick, the rib supporting it will be 3mm. Always remember to use a fillet radius on ribs.
  • Often a part’s wall thickness must vary due to the demands of the design. If this is a necessary feature of the design, it is important to graduate the wall thickness between the differing thicknesses of the walls. The best method of graduation is by using a radius to ensure maximum support. Using a simple step between wall thicknesses is almost guaranteed to create a fracture.
  • Coring. If your design demands a thick wall, coring is a method to get around the need. Coring is when a thick wall is hollowed out to create a ‘box’ of thin walls, complete with ribs and fillet radii. Not only will this be equally as strong as a thick wall, it is much less likely to warp and therefore will dramatically lower the chance of rejects. Coring also uses less materials than would a thick wall, and so, as pointed out before, would save on materials and running costs.

It may seem like such a simple thing, but even the excess thickness of a wall, multiplied by the number of units you’re producing, can cause many problems. There are multiple ways around using thick walls in your product design.

Post time: 12-12-2016