Sculptor i3 Upgrade: Magnetic Sheet Topped Heated Bed

Sculptor i3MK2.3

     This fall has been completely crazy for weather, November was partially frozen solid with heavy frost everywhere. I spent the month upgrading the Sculptor with a heated build plate on the y-axis, something I'd planned for since June 2018. I had been using a 65W laptop power brick for it's electrical harness, but that's only enough to power the hot-end and motors, not all that plus a heated bed, so my first step was to upgrade to the same 350W power module that I've been using on the Mega Kossel. Actually installing the power block was simple and straightforward, mostly just removing the old connecting wires and installing the new ones for the upgraded power supply.

Upgraded Y-axis bed support plate on Sculptor

     As for installing the heated bed, it was a bit more involved since I didn't have a standard i3 bed support plate installed already, so mounting one of those was the first step. I got mine from Spool3D here in Canada, it's made of 3mm aluminum with cut-outs for both 3 and 4 bearing setups, so I just had to install the appropriate printed connector for the drive belt and it was almost ready to mount the bed. For holding the bearings on I decided to take a page out of the old i3MK2 build manual and use zip-ties, one at each end of the bearings, it's surprisingly sturdy when the bearings are locked into their slots like that. Bonus is this form of mounting allows just enough flex to compensate for any slight misalignment that might get into the rails during re-installation.

Build Plate assembly with zip-ties

90W MK3 Heat-bed with Wanhao branding

       For the headed bed, I went with the classic MK3 PCB/Aluminum combo that most i3 variations are fitted with, in this case a pre-wired version that I'm fairly sure was meant as a spare part for Wanhao Duplicator i3 models, again from Spool3D. For my purposes, having the wiring pre-installed is one less step to sort out. I only needed to connect them to the control board and the electrical side of things is finished. For mounting screws I happened to have some countersunk head M3s in the parts bin, so the bed got reamed out to accept them.

M3 bolt with Countersink

Magnetic surface sheet kit

    For the actual working surface, I picked up the Wanhao Duplicator i3 Magnetic Sheet kit since I've been interested to see how one of the 'buildtak clone with magnet sheet backing' systems actually worked in practice. What's included is a sheet of thin, mirror polished steel with coated with adhesive on one side and a sheet of build surface material backed with what looks like an overgrown fridge magnet at first glance. Actually installing the system is fairly simple, just peel off the backing from the steel and stick it down to the build-plate like you would with regular sticker-sheet, then there's a protective blue film that needs to come off the front. And finally it's just align and drop on the magnet sheet to finish off installation.

Fully installed heat-bed with Magnetic surface kit

    After using it for 2 months, I can safely say that this kind of magnetic mount has become my absolute favourite, it has all the ease of removal that the spring-steel based ones are supposed to have with much simpler installation. I've tested it at upto 60C on a regular basis and it's held up nicely so far, I've only managed to put some minor cosmetic scratches on it from the nozzle during leveling, it's flexible enough that even the most stubbornly stuck bits of PLA can be removed without tools, just bend it at the right point and they come straight off, much safer than the sharp-edged scrapers conventional beds require.

Finished Sculptor i3MK2.3 with new heat-bed installed

     Overall, I'm happy with how the heated bed update has worked out, it's certainly proven perfect for running in cold weather, cranked up to 60°C it holds PLA  and TPE filaments down just fine even with the ambient temperature hovering around -5°C.