Importance of Lead Screw
A Lead screw is very much like the ball screw, although it has one exception that it doesn’t have recirculating parts. It is specifically designed to use the contact between rubbing surfaces.
A Lead screw has a similar function to a ball screw,
but it does not feature recirculation. A further difference is that it is not as an efficient a precision ball screw as a result of greater friction. While ball screws make use of two surfaces rolling against each other to create motion, lead screws are constructed with rubbing surfaces. These items are cheaper than ball screws however. Other names for lead screws can be translation screw or power screw. Lead screws are also linear actuators, transforming radial motion into linear motion.
You can avail of a selection of types of lead screw, the difference between them being the type of thread. V-threads, square threads, acme threads and buttress threads are suitable for lead screws. One of the most important issues opposing efficiency in lead screws is friction. The effects of this force has to be reduced as far as feasible at all times V-threads more often than not cannot be developed for lead screws as a result of quite a bit of friction between the threads, but in some cases they are chosen. Square threads are less cost efficient and have very square-shaped threads. Due to these threads however they do not have high levels of friction making them the most energy efficient lead screw.
A small angle is what distinguishes the acme thread. This angle is not difficult to cut, which makes the acme thread easy to manufacture especially when likened to the square thread method. As a result of this they are less expensive but there is an increase in friction levels due to the design. An interesting type of lead screw is the design that incorporates what is known as a buttress thread. A triangular shape is the basis for this thread which is less complicated to manufacture than a square thread. Surprisingly the buttress thread is as easy to manufacture as the acme thread. The most significant downside of a buttress thread is it is limited to a single direction of motion.
Some problems occur due to friction in a lead screw. This resistance to motion will sometimes create a large heat output and can cause overheating, an increasing severe problem depending on the levels of usage of the screw. Some lead screws can operate in reverse, but this depends on the amount of friction between the screw and the nut, the exact thread angle and the helix angle of the thread. However most lead screws are self locking, so that they are not free to move in all directions. A common caveat is to be sure to use sufficient lubrication when operating a lead screw, although this is determined by the screw and its friction levels.