How Lead Screws Convert Rotary to Linear Motion

How Lead Screws Convert Rotary to Linear Motion

The function of a lead screw is to take linear motion and convert it to rotary motion. A mechanical actuator mechanism relies on a sliding motion between a screw shaft and the nut. A lead screw differs from a ball screw because of its cost-effective makeup and lightweight applications. Let’s further review how lead screws convert rotary to linear motion!

How Does It Work?

There are two ways for a lead screw to operate. One method requires a fixed component while either the nut or the shaft rotates linearly, and this is a typical operation in helical pairs or printers. The second method is the nut or shaft rotating non-linearly, which usually occurs in lathes or presses.

The lead function of the screw is the total linear distance the shaft or nut travels in a single revolution. When the lead increases, the linear speed follows suit, and the load capacity on the lead screw will decrease.

Lead Screw Threading

A lead screw has three primary threading designs: buttress, Acme, and square. A buttress threading pattern transmits high axial loads into one direction and only works well in unidirectional applications.

An Acme screw design possesses a 290-degree angle and allows high load capacities. Acme screw threads have decreased threads per one inch, increasing the total lead. In contrast, a square thread has a 00 angle and holds less resistance and friction while in motion. Square threads are most suitable in power transmissions and jackscrews.

Examples of Application

Lead screws have various applications in multiple industries. Due to their various components, they are not suitable in high-load frequency scenarios with continued power transmission. They are a kind of kinematic actuation and work well in scanners, recorders, lathe machines, and wire bonders.

You can also commonly find these mechanisms in clinical settings like veterinarians or hospital equipment. In medical equipment like an infusion pump, the lead screw component is the primary function for fluid measurements that need precise delivery.

To learn more about Acme screw products and how lead screws convert rotary to linear motion, reach out to Wedin International today! We are industry-leading experts in machine assembly and we serve any industry!