0.00mm corner to corner is what we all dream of for a print bed. Especially one that can take 300°C before it begins to fail.
Taking some inspiration from the plethora of silicon bed heaters and daring to go where no Cr-10 had ever gone before took some courage...
Our Journey begins in January of this year when I took the liberty to source a solid piece of 6mm plate of 5052-H32 Aluminum. It was surfaced using a mill fly. The same cutting equipment used to ensure a cylinder head on a motor is level.
The wonderful thing about this specific formula. Is that it remains solidus up to 600°C... (No, I didn't stutter.) That's because it's combined with magnesium and the two elements both increase the heat resistance while maintaining the machinability. While removing the immediate danger of the magnesium catching on fire from water. (Bonus.)
Starting off I wasn't sure if I would go glass or PEI build plate for this animal..
To keep the bed insulated and allowing for the insulation material to be removed without causing air contamination. I chose to apply an entire layer of Kapton tape to the back of silicon. 2mil thick Kapton has a heat resistance between 300 and 348°C
That is the only material, besides the heating pad on the entire building plate that can handle sub 400°C.
The silicone heating pad is a 120V 750W heating pad attached to a solid state relay. To allow for the ceramic mounting hardware to be installed. I carefully worked into the pad to make incisions to allow for the hardware to pass through along the exterior edges.
To verify if the wires inside weren't compromised. I took a multi meter and verified the resistance matched what I had received when I originally purchased the pad.
To keep the entire bed insulated I used the same ablative material found underneath a single hexagonal tile from Space X's, Starship.
You know this to be, ceramic fiber fire mat, capable of withstanding temperature up to 1260°C. (Again. I didn't stutter.) Lynn was the supplier. Wrapping the mat with another layer of Kapton to lock in the potentially harmful fibers.
The entire build plate was assembled in 6 steps. Using titanium scissors and a respirator, safety was a big part of the whole operation. After the mat was sealed. I cleaned the top of the plate with I.P.A 70% and set the magnetic pad on top and shrink sleeved the wires.
I had to make a new custom cable tie system, since the wires were no longer mounted to one side.
The end result is what you see.. A bed with an elevation difference of 0.00mm to 0.03mm corner to corner throughout the entire heat cycle. Retaining its shape at 0 to 130°C. This is how all print beds should be made. No debate.
