i3Mega : Adding glass bed


Anycubic i3 Mega & ABS


I've discovered the hard way that the only working method for me to print ABS is to use ABS glue.
I.e. ABS dissolved in acetone.
Add a thin layer on the printing bed and that dramatically increases stickiness.
Printing ABS that way is a breeze (a smelly breeze actually).

So problem solved ?
Not really. Cleaning the ABS glue on the i3 mega is messy, smelly and takes a lot of times.
You have to pour acetone, scratch the bed gently with a toothbrush, again and again and again

I've never managed to completely clean it up. There are still some smears of ABS glue today.
 I guess i'd have to remove the bed and clean it up externally.


So i wondered : What if i had a borosilicate glass on top of the original bed ?
That would be easy to clean up.

So, here we go.
I ordered one on amazon, with metal large paper clips (should have taken bigger ones, but they do work).

The problem is now how do we compensate for the ~ 3 mm offset on the Z-Axis ?

It is explained in the anycubic documentation, but let me share my experience

There are 2 long screws left & right of the motors.
When the head goes up & down, those screws move.
Going home is basically going down till the contact clicks.



Be warned, they are really awkward to (un)screw.
Make sure you dont put clips in the bottom left corner of the glass, that's where the head is moving at start.

The idea is :

  • Put the glass on
  • Screw the leveling screws to the max (the 4 thumb screws at the corner of the original heating bed)
  • Using the menu, move the head Z axis so that it is ~ 1mm above the glass.
  • Then screws the  Z home screw until you hear the contact bip. Repeat on the other side.
  • Recalibrate the head the usual way using with a sheet of paper and the 4 thumb  screws
Done !



Tried printing ABS+ ABS Glue , no problem.
Cleaning : No problem. Remove the glass and clean it up with acetone in the sink. Takes 2 mn

Great success. The only caveat is that the glass is slightly smaller than the normal one, but no big deal.

Not time to try PLA & PETG.


Edit : Tried with PLA : flawless so far. Behaves exactly like the original bed/glass

Edit 2: nah, need to help the filament to stick with hair spray, all fine then

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