subject: Differences Between Ball Screws And Lead Screws [print this page] Ball Screws and Lead Screws are usually mentioned together as they are both examples of mechanical linear actuators. Along with this, they are often employed in similar situations. However are a few critical differences between the two designs, which mean that some applications are more suited to one of these screws than the other.
The biggest difference between a ball screw and a lead screw is the recirculating ball bearings incorporated into a ball screw assembly. This makes a ball screw more complex, but there are a number of pros as well. For example there is a higher efficiency level amongst ball screws assemblies than in lead screws. The levels of efficiency can be calculated through examining the lead angle, but 90% or higher is not unheard of amongst ball screw assemblies. As a direct consequence of this very high efficiency ratio, in conjunction with other features e.g. low friction, the driving torque of a ball screw can be just one third the driving torque experienced by a standard model lead screw.
Many ball screws can function in reverse, a further result of the low levels of friction. As a result of the ease of motion within the ball screw assembly, in general it is not difficult to alter the ball screws operational direction, and utilise it to change straight line movements into rotational energy. Ball screws are most applicable to situations that need high levels of efficiency and also good precision, as well as smooth frictionless movement.
Lead screws are commonly utilised in mechanisms where they can gradually affect their linear actuation. These tools cannot operate at the type of high speeds that are tolerable to ball screws, as they generate more friction. They are also less accurate, but can function with heavier loads. Therefore lead screws can operate in situations where the mechanism is not run at a relatively high speed, and it is not critical for the results to be extremely accurate.
