Ender 3 CR20 Belt clearance upgrade

thingiverse

This modification lowers the belts on the X and Y axes so that they run inside the extrusions on the motor side. It's a quick fix, not the ultimate solution. Hopefully this will spark some ideas in others who can improve it and maybe create a better solution. I have a CR20 but this should also fit the Ender 3 and possibly other Creality printers. By default the belts are not quite parallel with the axes which makes them rub against the extrusions and creates other problems. This is a design flaw by Creality that I haven't seen on other printers. Mathematically speaking, the belt will not be long enough when the trolleys are close to the edges, making the weakest point bend or flex a little, probably the motor brackets which are pretty weak. The belts are quite unstretchable. Having the brackets bend or flex causes the belts to want to travel from side to side on the pulleys. This is a clip that pushes the belt down into the extrusion. You'll need to remove the aluminum bed and Y-axis trolley to fit it. The X axis can be mounted without removing the X-axis trolley if you loosen or remove the left upper wheel Nyloc nut. The belt holds the clip in place. Pull on the belt and if the clip wants to move out a little when you pull, leave it there since it will want to stabilize into that position anyway. Make sure that the clip and belt are centered inside the extrusion, with sideways adjustability. The belt may chafe a bit where it goes through the extrusion because it's the same dimension as the hole in the extrusion, which should fix itself after a while when the rubber wears off a little. The size of the hole where the belt goes into the clip on the X axis is not quite aligned, done to fasten it better. The idler pulleys can be adjusted down a bit since they are bigger and won't be a problem. I drilled out some bigger holes for the screws on the X-axis idler bracket to allow more adjustment of the position.