Current box is machined aluminum and meets all of the specifications below but expands to much for the temp range.
The temperture range is -20 to 30 deg C.
The missing side is a 3x3 inch top.
Box needs to be strong enough to with stand a man walking on it.
Box needs to be very flat.
Need to be able to produce box affordably, must be under $200 in quanitys of 100. Under $100s would be even better!
I'm out of my area of expertise so I hope I've supplied the right parameters. Let me know if more data is needed.
Thanks in advance!