9. Bed
Degrease the bed
Aluminum bed
IPA degreaser, soap water, etc.
Action
Remove any possible machining oil, stains stayed on the surface of aluminum bed before pasting the heater pad and magnetic rubber pad.
Attach AC-powered Silicone Rubber Heater
Aluminum bed
AC-powered silicone rubber heater
Magnetic rubber of PEI plate (optional)
Action
Repeat step 1 to 3 as shown in the picture and attach the silicone rubber heater to the bottom side of aluminum bed. If you have ordered a PEI sheet, attach the magnetic rubber to the top side of aluminum bed before the heater, because the heater has some components that will flip-flop when you push the magnetic pad down.
Make sure no air bubble between heater and bed. If air bubble exists, heat will accumulate at that point due to no metal to conduct heat. Glue on the heater will vaporize and bubble will continue growing until you notice the awful smell. Then you’ll have to peel the whole heater off, clean the glue and re-install it.
Exam
No bubble is allowed!
Connect Thermal Fuse
Ceramic thermal fuse 150°C
Ceramic terminal block
High temperature RTV (room-temperature-vulcanizing) silicone
Thank Cube owner Brad Stinson for sharing the ceramic terminal block method.
Exam
Measure the resistance with a multimeter at the 2 connectors to AC power source. The resistance should be:
About 35 ohm for a 110V heater
About 138 ohm for a 220V heater.
Action
Stripe the sheath so 5~8mm wire is exposed for the ceramic terminal block.
Connect the wires to the block first before pasting them to the heater pad.
There is another repeatable 150°C thermal switch buried under the rubber patch.
Optionally apply high temperature RTV to to prevent the edges from separation over time. (Image courtesy: SK-Tank owner Michael K Johnson)
Connect Thermal Fuse
(11/08/2022) This method will be deprecated. Use the ceramic components in the previous page.
Thermal fuse 130°C
Round head bolts M4 x 8 (x2)
Nut M4 (x2)
Polyimide tape (a.k.a. Kapton tape, heat-resistant tape. Self-sourcing.)
Thermal paste (optional, self-sourcing.)
High temperature RTV (room-temperature-vulcanizing) silicone (optional, self-sourcing.)
Action
Make a small circle at both ends of wires of the thermal fuse. Connect the fuse with the 2 exposed Y connectors, and attached the fuse firmly onto heater with polyimide tape. Multiple layers of tape are recommended.
Optionally apply high temperature RTV to to prevent the edges from separation over time.
P.S. There is another repeatable 150°C thermal switch buried under the rubber patch. Bypass the one-shot 130°C thermal fuse if you think a repeatable thermal switch is safe enough.
Exam
Both exposed connectors are well covered to prevent electric shock.
The white cylindrical body is fully contacted with the heater so heat can be conducted to the fuse inside faster. Applying some thermal paste around the fuse helps heat conduction.
Measure the resistance with a multimeter at the 2 connectors to AC power source. The resistance should be around 30 ohm for a 110V heater, or 121 ohm for a 220V heater.
Optionally apply high temperature RTV to to prevent the edges from separation over time. (Image courtesy: SK-Tank owner Michael K Johnson)
Kinematic mounts
Bolt M3 x 10 (x3)
Bolt nut M3 (x3)
8mm steel ball with hole (x3)
Cable tie or string
Magnetic rubber pad (optional)
Actions
Attach 3 steel balls to the 3 supporting legs of bed as shown in the picture. If you use a magnetic PEI sheet, cut a gap at the corners of magnetic rubber for the bolts.
After ABL sensor fine tuning, secure the bed with a cable tie or a string to prevent from falling in case that bed brackets are not at the same height or faulty Z movement.