Sunlu T3 to Creality Ender 3 Conversion

The main goal in this kit is to bring my Sunlu Terminator T3 more in line with the two Ender 3 Pro's I own.  Since Sunlu no-longer makes or supports any FDM printers, I wanted my Sunlu T3 to be capable of using readily available and inexpensive replacement parts.

The electronics enclosure portion of this package will accommodate virtually any drop in replacement main board that would fit an Ender 3's electronics enclosure.  Since my two Ender 3 Pro's are currently sporting each a super cheap Makerbase MKS Robin E3 board, I decided to keep things uniform and used that same board with this upgrade.

Among the hardware oddities of the Sunlu T3 is the 12864 display that uses a 14 pin ribbon cable, rather than the 10 pin ribbon cable of the Ender 3 / CR-10 style 12864 displays, so in addition to replacing the stock Sunlu board with the MKS Robin board, I swapped the display to a proper Ender 3 display as well.

Be advised that Sunlu only tapped the lower inside 5mm holes at the front of the outer 40X40mm extrusions for attaching the electronics enclosure at the front.  Since I'm using both the lower inside hole on the left that is already tapped, and the upper outside hole on the left that is unthreaded from the factory for attaching my Ender 3 style enclosure, I did run a 5mm X 0.8mm tap through the left upper hole, and since I use a relocated power switch attaching on the right side of the machine, I tapped the right side outer hole as well.  While the electronics enclosure will probably hold securely enough using only one of the front extrusion holes combined with those using T-nuts, I still recommend tapping at least that upper left hole, if for no other reason than to match the appearance of the Creality Ender 3.

As I've relocated the displays for all my Creality style machines from the right to the left side of each machine, I did incorporate the little L shaped piece I use for connecting my display bases to the front of the machine into the electronics enclosure piece:  https://www.printables.com/model/606990-ender-3-left-side-display-extension

If installing the display on the left side of the machine isn't to your liking, I apologize, but there are a couple of good reasons for doing so.  Locating the display on the left places it closer to the electronics enclosure so ribbon cable routing is easier.  Moving the display to the left means the encoder wheel presses take place over and in front of the frame.  Additionally, I like to have my machines appear and function uniformly so I basically copied the configuration of my two Ender 3 Pro's with this upgrade.

One of the randomly recurring problems I was having with my Sunlu T3 since it was new was random layer shifts on the Y axis.  Bumping the current up on the Y axis stepper driver didn't solve anything, it just resulted in the motor running hotter.  Replacing the motor didn't change anything.  It turned out the problem resulted from Sunlu using a 4015 radial fan for cooling the main board and from Sunlu's use of tiny heatsyncs more suitable for A4988 drivers but not very good for keeping TMC2208 drivers cool.  Additionally, the 4015 blower for cooling the main board was obstructed and air wasn't moving over the drivers.  Adding a 4010 fan mounted directly over the Y axis driver solved the layer shift issues.  When I modeled the lid for the electronics enclosure in this kit, I decided to include provisions for two 4010 blowers that sit directly below all the drivers on Ender 3 style boards like the MKS Robin E3.  Perhaps that's overkill as I've used those Makerbase boards with integrated TMC2209 drivers and no active cooling in the past on other machines, but since a hot driver bit me on this machine already, and since I have the fans handy, I figured “Why not?”  I used 24v 4010's wired parallel, but you could get away with two 12v 4010's wired series if you wanted to throw some Noctua's in there.

The Y axis belt tensioner on the Sunlu T3 has its body incorporated into the top of the stock electronics enclosure.  The part named “T3_Y_Tension_Housing.stl” serves that function and attaches to the center 40x20mm extrusion using the screw that held the old structure in place.  The backstop for the T3's Y axis belt tensioner is a square steel plate with a hole in its center.  That piece will need to be pushed out through the front of the old electronics enclosure assembly before discarding it, and pressed into the “T3_Y_Tension_Housing.stl”.

Sunlu FDM printers are kinda niche these days, are out of manufacture and are unsupported.  I don't expect much, if any interest in this design but I do post pretty much anything I do.  Likewise, if there are any mods in the photo's that interest you, they're all right here on Printables…  I'm currently doing a similar upgrade to my Sunlu S9 Plus, a CR-10 clone, and will be publishing that in coming weeks…

UPDATE 04202025:  While I was working on my Sunlu S9 Plus's electronics enclosure, which is a little smaller than that of this kit, I decided to go with only two screw holes for each of the two 4010 fans I attach to the lid, diagonally opposed.  As I'm running low on metric screw hardware, I decided to steal four of the eight screws I'd installed those fans with on my T3.  I decided to remove the unused screw holes in the lid for the T3 enclosure and am adding the file here as:  “T3_E_Enclosure_Lid_V2.stl”.  I don't suppose it will matter much to anyone who may use this kit as the lid installs face down beneath the enclosure and won't be visible anyways, yet, since I made this change locally, I added version 2 of the lid here.  Use whichever version of the lid best suits your preferences.

Additional notes I forgot to include when I published this kit:

Creality Ender 3 drop in replacement boards use two pin connectors for both the X and Y endstop switches.  The Sunlu endstop switches have three pin connectors, yet are still only using two wires.  Those three pin JST connectors will either have to be cut down, or replaced with two pin JST connectors.

The ribbon cable for the 3DTouch sensor that came with the T3 will connect exactly as it did if the board you're installing has that five pin BLTouch header.  The MKS Robin E3 board I used doesn't use that five pin connector, but instead uses two three pin connectors, three wires on the “BL Touch” header and two wires on the three pin “BL Touch Endstop header”.

If you don't have the required JST connectors and don't want to purchase them, you can find printable JST connectors here:  https://www.printables.com/model/560373-jst-connectors-for-3d-printer-mainboards