Insulated Hot.plate

The heated platform of a printer loses heat by radiation, conduction and convection.
The top loses heat mainly by convection and radiation.
The bottom of it, however, primarily loses heat by radiation.
A reflective surface can return 99% of that radiation.

Mr Jeffrod has performed experiments to study various means of insulating the bed.

The control was the original heated platform with the glass plate:


The variations tested included:
insulation panel made of reflective aluminum
insulation panel with reflector underneath
insulation panel with aluminum flashing on top of the bed (painted black on top but reflective on bottom side)
insulation panel with both reflector underneath and the flashing on top

insulation panel made of reflective aluminum


insulation panel with reflector underneath


insulation panel with aluminum flashing on top of the bed (painted black on top but reflective on bottom side)


insulation panel with both reflector underneath and the flashing on top


The heating profile was charted for these assemblies with and without the IR heater array.


Conclusions:
The thermal mass of the platform (heater, aluminum  spreader and glass) is large relative to the heater's power.  Heating takes time.

The addition of an insulation panel improves heating rate only slightly at the lower end but without it the platform would not be able to reach 150C (used for PEEK)

Additional insulation below the panel has very little effect, implying that the panel is already accomplishing most of what can be done.

The IR array improves the rate of heating significantly.

Additional insulation on top of the glass improves heating rate significantly (but must be removed for printing!)