EXPERIENCE WITH THE POLY FOAM BOARD
I received my poly foam board from the laser cutting site - 1/2" thick foam with the holes cut to allow the lamp holders to sit properly aligned for a quick easy insertion into the honeycomb matrix.
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| Poly foam aligner mask in place |
First observation was that the foam is just too soft to push the lamp holders fully. It does help with some of the tilt such that they are very nearly correct even with this material.
Second observation was that with 1/2" foam the bulbs barely stick up out of the foam. I need some of the nylon lamp holder to be proud of the board in order to slide into the honeycomb cells and ensure the light is directly into each hole.
The brightness was adequate and this could have been made to work, but the PCB could slide up, down, left or right of its intended position because the foam surface doesn't let the holder drop into each hole.
NEXT APPROACH
It is time to take the design file and send it back to the fab, selecting a more rigid and less thick material. I believe 3/8" would be perfect for the height, but I will do more measurements before ordering the new board.
What is the lifetime of this foam? Having scraped and vacuumed degraded foam out a many old machines at CHM, I have a hatred of the stuff. I’m sure it seemed very practical and clever when they designed the machines, but only a couple of decades on it turns into a crunchy, toxic mess that dribbles into everything and sticks to small parts.
ReplyDeleteHi David
ReplyDeleteYes I too detest the 1960s-1970s foams and other materials whose plasticizers don't last, turning them into harmful debris or goop.
I haven't seem the degradation in newer materials, but I suppose they could suffer the same fate even if a bit later in their life.
In any case, I have switched to an acrylic plastic for the aligner.