One of the challenges when building a 3D printer for yourself is getting the correct belt length. Too loose and your belt will slip and jerk; too tight and it will skip steps. Both will affect your build quality and accuracy.
So here at T3DT we came up with the perfect formula to get the perfect belt length to use on any 3d printer belt drive system with added belt springs to give us just the right and best tension.
PC + ( PD *2) – BCD
PC = Pulley Circumference = Pulley Teeth x belt pitch or pulley diameter * Pi
PD = Distance between pulley centres
BCD = Belt Clamp Distance
These are shown in the diagram below.
For example if the pulley circumference is a GT2/20 tooth pulley which is 40 mm, the belt clamp distance is 15 mm and the pulley distance is 120mm then the calculation will look something like this …
Belt Length = 40 mm + ((20 mm + 120 mm) *2) – 15 mm = 305 mm
Once calculated the belt can be cut and assembled using the belt clamp.
The last thing to do is to fit on the tension springs to give you the perfect belt.