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.
Kinematic mounts
Left/Right/Rear bed mounts
Printed left and right bed leg guards (STL here)
Adjustable arm (2)
Ceramic thermal fuse
Bolt M3 x 18 (9)
Washer 3 x 8 x 0.8 (13)
Nut m3 (34)
8mm steel ball with thread hole (3)
Exam
While lifting the bed bracket manually by hand, there is about 1mm gap and the ball bearings don't fall out. If not, adjust the WWB limiter bolts.
Actions
Assemble the mounts as shown in the picture.
The bolt heads of these two M3x18 bolts below extrude out of the bed surface, and act as build plate pegs.
Pass the bed legs through the printed leg guards first before attaching the steel balls. The leg guards prevent the bed from falling off the bed brackets.
Adjust or rotate the arms later to meet the need of your hotend nozzle position.
Adjust the height of the Wobble Wafer limiter bolts so they won't block the bed arms. As long as the limiter bolt won't block the bed arm, and the other limiter bolt has 1mm+ gap to allow Wobble Wafer tilting, and prevent wafers from falling at the same time, they are in a proper range. Either method A & B in the illustrations works.
Attach AC-powered Silicone Rubber Heater
Aluminum bed
600W line-powered silicone rubber heater
High temperature RTV (room-temperature-vulcanizing) silicone
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!
Measure the resistance with a multimeter at the 2 connectors to AC power source. The resistance should be:
About 20.2 ohm for a 110V heater
About 80.7 ohm for a 220V heater.
Optionally apply high temperature RTV to to prevent the edges from separation over time. (Image courtesy: SK-Tank v1 owner Michael K Johnson)
Connect Thermal Fuse
Ceramic thermal fuse 150°C
Ceramic terminal block
Bolt m3 x 12 (1)
Washer 3 x 8 x 0.8 (1)
Nut m3 (1)
Actions
Connect the short wires of the bed heater to the ceramic block and the ceramic thermal fuse. Paste the ceramic block to the bed heater with high temperature RTV.
There is another 150°C repeatable thermal switch buried under the rubber pad of the bed heater, so you can optionally ignore the ceramic thermal fuse and connect the short bed wires together.
Exam
Terminals are connected firmly.
Drag chain
Drag chain
Bolt m3 x 10 (4)
Nut m3 (4)
Actions
Each link of the drag chain can be opened with a small flat head screw driver.