If I make the FFC cable longer than it needs to be, I can flop it around some before it leaves the oven, to reduce heat conduction.
It shouldn't be much, a bit of foam tape to keep it from cooling in airflow would be useful, too. If I were doing the bridges, the sense parts would be laid out differently (like, four-square) so one could do a dipole/quadrupole model of the sensors, and drive heaters accordingly.
On a sunny day (Sat, 28 Aug 2021 19:09:37 -0700) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:
You got me worried there for a moment about FCC certified flex cables... :-)
But OK now!
The length of the FFC, thermal conduction, is my concern. Phil H is down on 1mm FFC, and one doesn't mess with Phil. He's bigger than I am.
The thermistors are aligned on the center axis of the gadget being measured, directly below the skinny electro-optical strip inside.
I might flip the board over so the parts press against the gadget, if my mechanical designer permits. He's bigger too. These big guys just don't understand that I'M THE BOSS.
Most people are. Phil does seem to be appreciably more clever than you are, which probably should have more influence on your thinking.
The interesting is how much of a thermal gradient are you going to have from the centre of the skinny electro-optical strip, whose temperature is what you need to control, out to the outside world, whose temperature you can't control.
If you've got lots of insulation between the thermistors (and the electro-optical strip) and the outside world, the steep bit of the gradient is going to be in the insulation.
You might think about filling any air-gaps between the parts and the electro-optical gadget. Small volumes of air don't convect,and have a much higher thermal resistance thermal contact gunk (but that isn't all that conductive either).
Being the boss means that you carry the can if the device doesn't work. People working on the device do have an interest in getting it to work and if the boss isn't aware of that, the whole team has a problem (and most of them start thinking about finding a different boss).
It's nice working for a guy you like, but if he doesn't listen, things aren't going to go well.
I wanted to be sure I got it right, so designed and manufactured an advanced physical simulation of the system.
The flex can be long this way and spend a lot of time inside the cozy oven before it dives through a slot to the controller board.
Next step will be to hog an oven out of aluminum and test dynamics.
Apologies for posting on-topic.
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