Designing a water tight enclosure for IP66/67/68 2

[leonhart88]

Hi All,

I'm working on a project that requires an IP66 rated enclosure. This device has to have several buttons and LED indicators. I don't have any experience with designing water tight enclosures so I thought I would pick everyone's brain here, while doing my own research in parallel. The closest thing I've done is design some small containers with o-ring seals (no cutouts).

My project will initially be a low volume product, with the potential to be scaled up. At first, we are going to design the enclosure out of either machined plastic or aluminum (or an off the shelf if it is suitable). Later on, we can move towards injection molding.

My main questions are the following:

1. Assuming I am working with machined parts, or an off the shelf enclosures, what is the best way to add buttons and switches while maintaining the seal? I know there are some special IP-rated switches and LEDs, but they seem fairly expensive and are bulky. Is there a better way to do this (eg. heat staked or welded light guides, or mounting normal buttons/LEDs but with epoxy)? I am sure the examples I gave would work for IP66, but I'd like to find out the best practice for doing such a task.

2. If we were to injection mold these parts, are there special ways of injection molding buttons and LED "windows" directly into the enclosure?


Thanks,
Phil

 

[itsmoked]

Phil;

A couple of things comet to mind which, of course, depend largely on what's in your enclosure.

Sometimes you can use 'touch' inputs which can work thru the material without any penetrations.

I've done several designs where you put all the penetrations you need for the user into the face of the product then you apply an overlay with windows and labeled buttons etc which bonds to the rest of the face. I've never bothered to actually 'spray the water' but none could get thru or under the overlay given the adhesives used. Then, for the wire entries you use the typical IP rated cord/cable grips.

There are soOOOOOOooOOO many commercial enclosures available from the usual suspects, that I have a hard time seeing why someone would need to go to the expense of a ground-up design of an IP rated box.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[drawoh]

leonhart88,

Commercial-Off-The-Shelf (COTS) IP66-68 panel components may be expensive, but how do they compare to panel components you design yourself to meet IP66-68? They don't just have to be water resistant. They have to work! The same goes for the enclosure itself. There are COTS enclosures that meet standards. If you buy these and COTS compliant panel components, you can be confident your complete design meets standards.

If you don't like the COTS stuff, you need to design your own system and test it to verify that it complies with standard. This is especially true if you have signed a contract promising compliance. IP66 is "powerful water jets". I recall that NEMA4 is a Ø1"[ ]hole at 64gpm for half an hour. What fun! IP68 is continuous immersion, down[ ]2m, I think. You probably need your own test facility so that you can test, modify and test again. This is a good idea if you plan to keep on designing new sealed enclosures. If you can work out a reliable sealed joint, you can port your design to new product.

I strongly prefer to design my electrical enclosures from scratch. My custom designs can easily be configured to provide access to and convenient mounting of components, and cooling of same. I don't need to keep out water. It sounds like a challenge.

--
JHG

 

[leonhart88]

Hey Guys,

Thanks for your replies. It's invaluable to have other people's advice, especially when they have more experience in this area than me.

I am definitely considering IP rated COTS enclosures along with membrane button overlays. I have no idea what the costs are for the overlays yet, but I will have a better idea in a couple of days. We need to have a cutout at the front of the enclosure for an infrared LED, which may limit what COTS enclosures we could use.

I agree that having to go through the IP certification tests will be somewhat of a pain, but we may need to do it anyway. I've been told by various manufacturer's of COTS enclosures that their ratings no longer apply after any cutouts are made and the enclosures need to be tested again. Of course, I'm sure they are more likely to pass because the design is already sound.

I'll continue to investigate my options and hopefully pick the best one for our application. Thanks again!

 

[itsmoked]

[URL unfurl="true"]http://www.markingsystems.com/index.html[/url]

I haven't found a less expensive overlay maker yet. And, these overlays are top shelf. 4 x 3" with a window is something like $700 for a couple hundred pieces.

Keith Cress
kcress -

http://www.flaminsystems.com