Someday I'll laugh about all this...
It's been a long two weeks.
After untold emails and phone calls, (including midnight skype-ing to China), we've reached some conclusions:
1. Turns out that there was some confusion about silicone molds for Polypropylene (PP); ABS vs PP and other technical details that I doubt anyone really cares to hear about. Summary: the manufacturing engineers have convinced us that we do not need another prototype.
2. While these conversations were taking place, we were rechecking everything before giving the order to cut the steel molds. One of the final tests we ran was a "light leak" test, just to double check the light baffles in the latest prototypes. We loaded up 4 sheets of ISO 400 film, set the tank under an 80 watt light, waited an hour and then processed the film. Of course, since we've never seen even a hint of a light leak, we knew the film would be blank. Here's what it looked like:
Wow. Bummer. It was only the two outside sheets that were affected and at first glance, the pattern roughly matches the holes in the outside edges of the inner baffle. But it was at the far end from the fill/drain, so maybe it was the vent port? After all, light can bounce around in strange ways.
Now I won't waste everyone's time describing the fiasco that followed but after numerous mods to the baffles, followed by testing/processing; we concluded that everything was light tight.
So, as Sherlock Holmes would say, "once you've eliminated the impossible, whatever remains..." That meant that light was leaking through the solid plastic tank.
Here's the embarrassing part, (that we'll laugh about, someday, maybe); the prototype tank isn't solid. (Remember, the tank is made out of five pieces of plastic?)
While everything looks solid in the daylight, here's the tank, in a dark room with an flashlight illuminating the inside.
Turns out that the prototype shop used a clear epoxy to assemble the tanks. Not enough light gets though to matter in normal processing; only by setting the tank under bright lights for an hour did it show up. Darn.
The good news is that the light baffles are now over-optimized. The bad news is that we lost a week (and wasted a lot of film.) Like I said, someday we'll laugh about this.
The mold engineers are reviewing the final design files and should submit their comments tomorrow. Hopefully, we'll be cutting metal by the middle of the week. At that point, they will give us the updated production schedule.
Thanks for your patience, we'll keep you posted.