White Bear Lake, MN (PRWEB) September 04, 2013
In the last installment of this series, the process of assembly and bonding was discussed with respect to different plastic enclosure design concepts. These concepts included UU boxes, L-Slide, and Removable Cover Enclosures. In this installment, the latter enclosure design will be detailed with regard to making “water resistant” housings.
Since the entire five-sided base portion of the housing is already bonded on all seams and edges, it is essentially “water-tight”. The main concern comes with the plastic cover and the attachment point. The design most common used it that which has a rail/frame around the inside perimeter of the 5-sided base housing. This frame has holes CNC milled in it for brass inserts and is set one material thickness lower than the top edge. This allows for clearance of the placement of a gasket and also creates room for the cover to be screwed down tight and to compress the gasket.
The gasket itself is a custom die-cut neoprene gasket with holes properly cut into it to line up with the brass inserts in the frame piece. The gasket has a pressure sensitive adhesive (PSA) backing which allows it to stick on the plastic frame piece.
The only concern now is the seam which is seen around the perimeter of the flat cover piece. Although the “water-resistant” factor is high, it is not necessarily “water proof” or submersible. Considerations should be made by the customer as to how this housing will mount in its desired environment. Pooling could happen if the seam is mounted upward making it possible for water to eventually leach in. It is best to have the cover facing the ground in extreme wet conditions.
Envision Plastics prides themselves on offering many styles of custom plastic enclosures to fit many applications. However, they cannot certify their housings to any IP or NEMA ratings. All design options are thoroughly discussed with clients prior to manufacturing to ensure the best possible plastic enclosure construction method to meet the requirements of the project.
In the next part of this series on how to design plastic enclosures using NMR, methods of PCB mounting within the plastic housings will be discussed.