Importance of Screws in Waterproof Design

Hello, everyone. I’m Isei for structural design section.

Many people tend to pay attention only to packing parts for a case when designing waterproof. Actually, more attention should be paid to the screw part than to the main section which has to be waterproofed. Since the screw parts are placed at multiple locations, it is necessary to give careful consideration to their variations when you do the waterproof design.

In this article, we would like to talk about the frequently asked questions about a screw structure in waterproofing design and points to pay attention to when considering it.


♦ Question 1:

  • What specifications are required for a screw used for waterproof?

♦ Answer 1:

  • In case of a structure where screws are fixed on the inside of the case packing, water may leak through the screws, so it is necessary to use waterproof screws with O-rings. (Figure 1)


Figure 1: Example of waterproof structure


♦ Point 1:

  • General-purpose waterproof screws are not available in many types, and the shape and length of the screws may not match.
  • For this reason, it is often the case that a new dedicated product is created, which requires a long manufacturing period, so it is recommended to consider this from the initial stage so that the design plan is not affected.



♦ Question 2:

  • What are the most important things to keep in mind when using waterproof screws?

♦ Answer 2:

  • Securing a clearance against an O-ring deformation is most important.
  • If the clearance is secured, a bearing surface of a screw will touch closely consequently providing a good structure. (Figure 2)
  • If the clearance is not secured, the O-ring will not be fully deformed and the bearing surface of the screw will float, causing the screw to loosen and increasing a risk of water leakage. (Figure 3)



♦ Point 2:

  • Since a volume required for deformation differs from each O-ring used, it is necessary to consider securing an appropriate clearance for each condition.



In addition to the above, there are various design constraints on waterproofing screws, which require appropriate selection.

We can propose an appropriate structure based on our experience in the development of waterproof equipment, so please feel free to contact us.


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