Static seal for consumer product to reach IP67

[Trying1]

Hi,
I am looking for some help. I have a consumer product to design. One of the requirements is to have an IP67 rating.
Does anyone have a design of a good seal. The product is 2.5mm injection moulding upper and lower casing.
seal section and compression ratio would really help.

Thanks in advance, I don't want to reinvent the wheel!

 

[DesignerGuy16]

Simple o-ring/gasket would likely suffice. Parker has specs for o-ring grooves to be liquid tight. It's all based on a % compression and seal area.

Mind you, this product may see some extremes like plane shipping in an unpressurized cargo hold, etc. If you have issues where the product can take in water you can also look at membrane vents that will let only air in, but let air and water vapor escape. This works to relieve the pressure building up inside the product so there is less stress on the seals themselves.

Google "Parker O-ring Handbook" for a start.

James Spisich
Design Engineer, CSWP

 

[lumenharold]

A possible vent source would be WL Gore. For soaking up moisture there is also this stuff:

http://www.multisorb.com/

Harold
SW2009 SP4.0 OPW2009 SP2 Win XP Pro 2002 SP3
Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
nVidia Quadro FX4600

http://www.lumenflow.com

 

[Trying1]

Thanks guys.

I like the idea of soaking up any moisture.
I like the o-ring data, but the shape of the product is not round, and i feel that a o-ring section cut to length and then glued together will not do the job.
But i can take the %ratios etc and make a moulded profile to suit.

Thanks

 

[btrueblood]

O-rings are stretchy and bendy, and can easily conform to a (radiused) profile of just about any arbitrary shape. Just mold the groove, then find a sized O-ring that fits. If you really have to, you can get custom O-rings cut and vulcanized to any size you want.

 

[NomLaser]

What makes you believe that the cut and glued o-ring wouldn't suffice? This is how a lot of drive belts and o-rings are formed. If done correctly, you will have a hard time finding the seam. I've used this method on IP67 rated boxes in the past and it worked great. Just be sure you have enough clamping force on the gasket to get the % crush that you want to achieve.

 

[Trying1]

NomLaser,
Had a bad exprience about 12 or so years ago with a cut a shut o-ring. But i take all you points and reearch the data.
I am sure that the tech/tols are better now than they were oh so long ago.

Thanks for all the help

 

[lumenharold]

If your volumes will justify the expense for automated dispensing equipment, form in place seals are nice. They never come out of the groove when installing the cover component.

Harold
SW2009 SP4.0 OPW2009 SP2 Win XP Pro 2002 SP3
Dell 690, Xeon 5160 @3.00GHz, 3.25GB RAM
nVidia Quadro FX4600

http://www.lumenflow.com

 

[IRstuff]

One thing to watch out for is that the tighter the sealing, the more likely it is that the system will asymmetrically take in moisture, even if there are no leaks.

Typical scenario, daytime heat causes pressure buildup, which equalizes across the seal interface. Nighttime coolness causes partial vacuum, which equalizes by sucking outside air/moisture. This is particularly bad in a system where dew can collect on/near the seals.

Make sure you have a dessicant that can maintain internal RH for the duration of the rated life of the system.

TTFN

FAQ731-376

 

[btrueblood]

Yes, a super-glued o-ring, especially in larger section sizes and large % squeeze, can come undone, especially if the joint is made/broken a large number of times. Super-glue forms a fairly brittle/stiff bond, and it gets worse if the splice is poorly made with too much glue in the seam. Vulcanizing presses exist that can form a truly seamless splice on most o-ring materials. There are also companies that will splice rings for you, one we use makes spliced rings for us cheaper than we can buy cord stock and super-glue our own rings.