Incorporating a LED indicator into a Plastic Enclosure with Injection Molding 2

[innominata]

Quite often I see plastic enclosures with light indicators that I assume are waterproof but are not removable or fitted, rather bonded to the surrounding plastic.

Looking at the indicator you can see that it's often a light pipe. How exactly is this achieved, is it overmolding and are there any other techniques that are able to do this when making an injection molded part?

Examples:

Spoiler

 

[drawoh]

innominata,

A two-shot injection moulding process will generate a waterproof window. The LED can be mounted behind it. You could glue an LED into a plastic housing, which would also be waterproof if you do it carefully. Moulding the LED in place should be feasible, although I think it would be a bad idea. Think about the heat.

--
JHG

 

[ctopher]

The lighted bush buttons we make are clear molded/machined, then painted (either inside or outside), masking the area where the LED sits.

Chris, CSWP
SolidWorks
ctophers home

 

[btrueblood]

We make parts with a molded pair of LED windows, created by directly overmolding a fully assembled and soldered circuit board: first with the clear lens material, then the rest of the board is overmolded with an opaque black material. Both types of overmolding resins are low melting temperature nylon derivatives, and are molded at fairly low pressures compared to standard injection moldings. Google the terms "low temperature overmold" and "low pressure overmold" - there are a lot of places doing it. Krayden is one doing it, and has some YouTube videos detailing the process(es).

 

[innominata]

What textures typically work well for the exit surface if you're using polycarbonate?

 

[drawoh]

innominata,

If your LED is merely an indicator, a frosted surface should work nicely. If your indicator is directional like a car tail light, your polycarbonate moulding needs to be a lens of some sort.

What do you want to do?

--
JHG

 

[innominata]

I want to have an indicator. I assume with frosting you can have it apply only to the external surface.