Epoxy encapsulation - jigs & assembly positioning

That's a good approach but would probably not be practical. Our labor costs are very high and we need to get this down to a single step process.

You could 3D print an entire 'tree' of the required positioning elements and break them off the tree for the potting process. Precise placement is what you wanted, so additional steps are going to be an unavoidable consequence. But I would 3D print something that stays in the potted unit, not a pre-pot partial fill and cure then backfill process as that creates parting lines in the potting

Then make 3mm to be the thickness of the potting container.

RL

Then make 3mm to be the thickness of the potting container.

RL =================================================================

Have you made measurements to see what the size variation on the sensor is, then on filled but unpotted boards to see what the height of the sensor end from the board is after soldering, and if you support the board as it is supported in your mold what the height variation of the sensor is before potting? That way you know how much of your total tolerance comes from each contributor - maybe you get a slightly different amount of "float" on the solder each time and that is your major source of variation, or whatever, so improving the mold won't help at all. If it's the soldering step maybe a weight on the sensor to press it down in the oven? If all of those dimensions vary too much you might need to use a spacer from sensor to mold to position the board, then clamp it somehow in the mold, then remove the spacer so you get a solid epoxy fill. Maybe something like drilling a hole in the mold over the sensor end and having a long plug to position the board (possibly onto 4 spots of epoxy and hold while they cure), and then replace that with a short plug to seal the mold for filling? Just thinking out loud here.

----- Regards, Carl Ijames