The hex file is converted as part of the Verify (Compile) process.
Select File:Prefences, check Verbose output
When you compile the last 2 lines that are displayed are:
C:\Users\Owner\AppData\Local\Temp\build1191639898936270974.tmp\eightx32display_progmem_eeprom.cpp.hex
Binary sketch size: 8,362 bytes (of a 130,048 byte maximum)
And there's your hex file.