Ball screws can be considered as a system which comprises the screw and the nut, achieving linear motion with high precision and/or high speed. Stiffness is also high and ball screws are capable of operation in elevated ambient temperatures. Servomech ball screws have diameters from 14 to 100 mm with efficiency at about 90%. Compared to hydraulic and pneumatic systems, ball screws are easy to control and cleaner. Compared against belt driven systems and linear actuators they are more precise and can be faster at up to 2m/s linear speeds.
Servomech machine their ball screws in-house and so are totally in control of design and quality. The screws are manufactured by rolling or by a process known as whirling which produces a quality similar to grinding. Accuracy grades range from class 7, which is suitable for the majority of applications, up to class 3 which is high precision suitable for machine tools. Screws are stocked in lengths up to 5.7m with a range of pitches from 5 to 40mm.
Ball nuts are also manufactured in-house to DIN 69051, matching the screws. Two ball recirculating systems are used – the radial liner where the balls made one revolution before being returned to the original track, and frontal deflector where the ball raceway travels the whole length of the nut before returning. Single nuts are either standard or preloaded to remove backlash, and double preloaded nuts have higher load ratings.
Assembly of Servomech ball screw and nut is to ISO 3408/DIN 69051