4 Things to Consider Before Purchasing a Lead Screw
Lead screws are a great linear motion device that efficiently translates rotational motion to linear motion, but until recently they only gave fair accuracy and repeatability. Lead screws are a great linear motion device that efficiently translates rotational motion to linear motion, but until recently they only gave fair accuracy and repeatability.
Top producers of lead screws today can deliver.003"/inch lead precision as standard and much better upon request. These businesses also offer a variety of sizes and lead to picking from and are happy to make custom-sized nuts in any size or form to fit these screws.
What is a Lead Screw?
A mechanical linear actuator that transforms rotational motion into linear motion is known as a lead screw. Its functionality depends on the screw shaft and nut threads gliding past one another without using ball bearings.
Because the screw shaft and the nut come in direct touch with one another and have a wide surface area, friction losses are larger. Lead screw threads have changed over time to reduce friction, though.
The following four considerations should be made by every engineer when choosing a lead screw.
Whenever possible, use PTFE coatings:
You may greatly improve the lifespan of your lead screw assembly for a very low cost. The nut is always the first component to break, and covering a lead screw with PTFE will increase the nut's lifespan by a factor of 8–10 times.
Make sure to ask for solvent-based coatings that do not outgas or wear because some manufacturers utilize water-based PTFE coatings that can wear down over time and lead to contamination. Even in demanding situations, the majority of good PTFE coatings need to last 25 million to 80 million inches of travel without wearing.
Ask for customized nuts:
Try to combine as many other various pieces that are attached to the nut into its design since lead screw nuts are created from various polymers, unlike ball screws and ball nuts, which are very difficult to make. Nuts are commonly manufactured from plastic blocks, sheets, or bar stock.
End Straightening and Machining:
Lead screw manufacturing materials are simple to machine and may be done on any standard lathe, mill, or OD grinding machine. If you only need to machine one or two prototype parts, this is simple and, in most situations, faster than waiting for the manufacturer.
However, since it's
they do every day, it's best to let the manufacturer handle the task if you're ordering multiple screws and the machining needs to be extremely accurate. If you are having the manufacturers handle the machining for you, they will typically include the straightening processes in the cost of machining.
It can be challenging to hold onto the lead screw without harming the machined ends or the threads when mounting it in your machine or device and attaching bearings, lock nuts, encoders, and other parts.
You can install a lead screw without affecting any of its essential measurements by adding a few flats to the outside diameter of the screw in the threaded area. The apartments will enable you to You can add flats without losing any movement by having the screw cut in such a way that the nut can travel over them.