I am using GT2.5 open ended belts so the carriages are designed to grip both ends. I printed and tried a few integrated belt gripper designs before I settled on the one below. It is made so the belts pass over each other and are secured so the ends pull from the opposite side of the carriage, pulling the print layers together, not apart like it would if each belt was attached from the top and bottom. This is important especially if the chamber is heated as I don't want any delamination of the part. This also means I don't need to worry about too much belt tension breaking anything. A 6mm long piece of 1.75mm filament is pressed into the eye where the belts fold over and becasue the teeth mesh together they cannot pull out. I yanked on both belts really hard and there was no movement so I am very happy.
|carriage with belt fitted and securing nuts and bolts|
|close up showing the belt fed into the carriage and the small pieces of filament|
locking the end loops
The belt grippers are located dead centre between the linear rods in both the x and y direction so there will be lateral forces on the bearings from the belt pulling the carriage up and down. This also means that the steppers are mounted off centre to keep the timing belt centered to the carriage.
Like the end effector each carriage has a 10mm diameter N42 magnetic ball JB welded to it.
|Complete carriage assemblies fitted|
|close up of the|
carriage assembly with bearings fitted