Ball Screw vs. Lead Screw

One of the common methods of driving a linear motion with the assistance of linear bearings are by using screws. Which can be powered by motors or hand driven. Two of the common types of screw system in the market are ball screws and lead screw systems which are more precise compared to other forms driven system (e.g. Pneumatic).

Ball Screws

Ball screws, as the name imply, is a system that relies on balls to convert the motion it requires. It runs as the same technology used in recirculating ball bearings found in linear bearings, and also subject to the same pros and cons found in them as well. 

Due to the system it uses, it has a much lower friction, and able to have very high precision. It is suitable for high running continuous cycles and are able to run higher axial dynamic loads than lead screw nuts. Hence, using a smaller motor as compared to a lead screw is possible, however, when used in situation where back-driving is not allowed, they will be required to be mated with a motor with brakes. 

                                                                                Figure 1: Lead Screw Technology

Lead Screws

Lead screws in general, is a more cost-effective system compared to a ball screw system. However, they are generally suitable for simple positioning functions with low cycles. In most production cases, the lead screws are manufactured by a rolling process which is much more cost effective than machining from a piece of shaft. The nuts are made typically of injection molded or machined using different types of metal or polymer material. 

With the ease of such production methods, this enable manufacturers like igus®, to produce nuts in many different designs with flexibility to adapt the right method to the design of the nut. Both the lead screws and the nuts are also able to be 3D printed using our igus® materials with exceptional tribological properties and able to cater to producing rapid prototypes. With different geometries from ACME, Trapezoidal and many more.

A common shortfall from lead screw systems in certain applications would be the presence of backlash. This is a case of the difference in technology between a ball screw system vs. a lead screw system, where the ball screw operates via rolling and the lead screw operates via sliding where some extra clearance is required to enable a smoother transition. 

Conclusion

Despite that, solutions to counter such backlash can be in for of Zero-backlash and Pre-loaded nuts which igus® is able to offer. The most important aspect of igus® polymer nuts is that all its polymer materials are self-lubricating and works well in many messy environment, avoiding unnecessary maintenance that other system that requires lubrication encounters. 

dryspin® Lead Screw Technology Samples are available upon your request.

For more information and selection of out lead screws, please do visit our website.