A new frame for Sunhokey printer to increase build size to 11x11x9 inches.Buy Sunhokey acrylic 3D printer. Print these parts. Build a 11.5 inch by 12.5 inch heat bed and buy 4 M8 nuts and about fifty m3-12 screws and m3 nuts. Sunhokey printer includes enough T2.5 belt for this, but if you already cut it, you'll need to buy more belt. To make MKS Gen-2Z V1.1 board work with two extruders, cut the traces from the Z2 dir and Z2 step pins to RPK4_M2. Then wire the Z2 dir and Z2 step pins to pins 5 and 7 in AUX-1 as in the photograph. Then modify Z_STEP_PIN=26, Z_DIR_PIN=28, Z_ENABLE_PIN=24, E0_STEP_PIN=46, E0_DIR_PIN=48, E0_ENABLE_PIN=62, E1_STEP_PIN=57, E1_DIR_PIN=58, E1_ENABLE_PIN=62 in pins.h in Marlin. Plug your extruder 0 into Z1 and extruder 1 into Z2. Wire your two Z motors in series and plug them into E0. If you probably don't have to modify the dir pin because Marlin probably doesn't ever run the two extruders in opposite directions. But I haven't tested it that way.