Proper Sealing Requires Expert Engineering

Posted by Kaysun Corporation on Feb 20, 2012 11:00:00 AM

blank.pngSealing is one of the most important steps in the production process—especially if the product’s performance could be compromised by atmospheric elements or particulate matter like dust. This is particularly true forsensitive electronics with medical, defense, and industrial applications. Water, humidity, dust, and other liquids can penetrate into these devices and result in malfunction or failure if they aren’t sealed properly. 

The number-one factor in having strong seals that work flawlessly is that the plastic parts must be designed and molded correctly, with the seals in mind. This is a step that is sometimes overlooked by manufacturing companies. If there is too much variability in tolerances, the following problems may result:

  • Parts aren’t flat enough to seal cleanly with a gasket-type seal

  • Parts have excessive parting lines on the sealing surfaces that create leak paths

  • Parts don’t meet dimensional requirements consistently enough to form a seal

The keys to obtaining a good seal are 1) forward-thinking design, and 2) consistency in the part manufacturing. Not only does a good seal have to be planned into the design process, the mating components must be manufactured with consistent precision.

The conditions of use for the part or product must also be considered when evaluating seal possibilities. For example, with fuel and coolant applications, material compatibility is a top concern because the physical characteristics of certain materials change in the presence of fuel and coolant, creating leakage issues.

Submersible applications are the biggest sealing challenges; this is where having high-precision molded parts is extremely critical. Creating strong seals that keep fluids out when the product is immersed is much more difficult to do when the system/parts are exposed to pressures that are constantly acting to break the seal. Any small imperfection in the part may escape detection during in-process leak testing but fail in the field after enough time has passed, so precision parts are a must.

Sealing is a key part of the manufacturing process and needs to be approached uniquely for each product to make sure that design and material issues are not overlooked. The first step is making sure the materials and design are validated with the seal and mating parts in mind; the next step is using a robust, highly controlled molding/manufacturing process to produce high-precision parts that will allow full, appropriate function of the seal. Companies need to ask about sealing when they are looking for an injection molding partner to produce a part that requires high-performance seals, especially for mission-critical applications.

Kaysun Corporation's engineers are available to assess the ever-changing needs and select the proper resins and production methods to meet this demand. Please contact us to assess and scope your next project.  Contact Us Today.