13. Enclosure
Temperature limit of Servo42C / S42C
The MKS Servo42C & BigTreeTech S42C PCB have a temperature limit of 55°C, and with the stepper covers installed they usually work well in a 60° chamber.
Further modification should be done if you plan to run a higher chamber temperature, or the extruder might crash/bump violently due to faulty compensated positions from Servo42C / S42C. Here are some suggestions:
To enhance the heat insulation capability, paste aluminum foil cotton liners inside the panels, or even attach some rock wool pads outside the printer, as shown in the pictures.
For the cooling reason, relocate the electronics at the rear side of the printer.
For the cooling reason, open 2 holes on the top panel and attach two 3015 fans blowing air down to the Servo42C / S42C PCBs.
For the cooling reason, use liquid-cooling pads to XYE steppers.
Use high temperature XY steppers.
Example: using aluminum foil cotton liners
Example: using rock wool pads
Panels
PE panels (5)
Magnet & iron pad (14)
Countersunk bolt m3 x 08 (56)
Nut m3 (56)
Silicone stripe
Exam
Don't fasten to nuts too hard as they might break the panels.
Actions
Differentiate the left and the right panels. The right one has two more slots for printed panel clamps as shown in the picture.
Magnets crack easily so BE GENTLE when you separate or put them together.
Peel the 3M release paper on the 14 iron pads but leave those on the magnets alone unless you got OCD like me. A knife or needle helps on this tedious task.
Do the magnets first and paste the silicone stripe to the contour edges of the panels later.
Note there is no silicone stripe between the 2 front door pieces.
The enclosure panels below are from an early stage prototype. Holes are fewer in later versions to keep more heat inside.
Door Hinge
Hinge (2)
Hinge ⇔ Smaller door trim
Bolt m3 x 15 (4)
Nut m3 (8)
Washer m3 x 8 x 0.8 (4)
Hinge ⇔ Larger door panel
Bolt m3 x 8 (4)
Nut m3 (4)
Washer m3 x 8 x 0.8 (4)
Exam
Don't fasten to nuts too hard as they might break the panels.
Actions
The smaller door trim
The larger door panel
Panel Clamps
Printed panel clamp (12) (STL here)
Left Stepper Cover
Left cover steel sheet (the smaller one)
Kapton tape (not included)
Ruler
Actions
Place the left cover sheet as the orientation shown in the picture. Paste Kapton tape, use a ruler as a folding helper and follow the sequence to fold the edges.
Paste kapton tapes at the outside to help secure the edge if there is no locking tab in the step 4.
Right Stepper Cover
Right cover steel sheet (the larger one)
Kapton tape (not included)
Ruler
Actions
The same as the left cover.
Attach Stepper Covers
Foam stripe
Folded left/right stepper covers
Exam
It makes noises if the flange of GT2 driving pulley grinds the cover. Fasten the M3 bolts or flatten the cover if it warped.
Actions
Paste foam stripes on the inner side of the frame as shown in the picture for better thermal insulation and to prevent noise.
Loosen the 4 RH M4 x 10 bolts of the stepper mount outside the frame.
Loosen 3 of the 4 M3 x 6 bolts at the stepper.
Remove the belt.
5. Attach the stepper covers as shown in the pictures.
6. Attach the belt back.
7. Fasten all bolts.
Do the same steps to both right and left covers.
PTC Chamber Heater
Heater box
Printed heater box (1) (STL here)
Nut m4 (8)
6015 fan ⇔ Heater box
6015 fan (1)
RH bolt m4 x 25 (4)
Nut m4 (2, as spacers)
PTC heater ⇔ Heater box
PTC heater (1)
RH bolt m4 x 10 (4)
Heater box ⇔ Bottom ACM panel
RH bolt m4 x 10 (4)
[For Beta version only] Holes on the frame for the heater box might be mis-aligned. Please use one bolt at the steel frame, and might drill new holes on the bottom ACM panel.
Exam
Seal the exposed circuit with RTV silicone rubber to prevent from electric shock!
Make sure the bed won't crash into the heater box.
Clean all support and debris before inserting m4 nuts into the nut slots, and test if m4 x 10 bolts fit. You might need to expand the bottom holes for m4 bolts to 5mm by drilling or a solder iron if heavily warped. Superglue helps on delaminated layers.
The heater box is placed in a skewed direction to avoid the bed crashing into it. If the bottom of box warps heavily, fasten all the bottom nuts might bring layer de-lamination. Prioritize the 2 bolts at the steel frame over the 2 at the ACM panel.
PTC Heater Wiring
