International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 06 | June 2019 www.irjet.net p-ISSN: 2395-0072 © 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 769 Review on Comparative Analysis of Ball Screw & Lead Screw Yashashri Dhaware 1 , Prachi Palkuntwar 1 , Harshal Narkhede 1 , Rushabh Meher 1 , Priyanka Chavan 2 , Bakhtiyar Gandevia 3 1 Student, Mechanical Engineering, Pimpri-Chinchwad College of Engineering and Research, Pune 2 Assistant Professor, Mechanical Engineering, Pimpri-Chinchwad College of Engineering and Research, Pune 3 Managing Director, Machine Reconditoners Pvt. Ltd, Pune ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - A ball screw uses recirculating balls to minimize friction and maximize efficiency. Design of ball screw is more complex, and requires hardened precision bearing surfaces and a ball recirculation mechanism. A lead screw has low coefficients of friction between sliding surfaces. Lead screw is compact in size. It offers design flexibility, corrosion resistant and can be made to self-lock for vertical applications. It is possible to design lead screw in optimum way if it is in eccentric loading. The main difference between a ball screw and a lead screw is in the way the load is carried between the moving surfaces. With the increase of screw speed, ball screw pair of noise levels are increasing, and the higher the speed, the faster sound pressure increase. Lead screw has relatively straight-forward geometry, performance and offers flexibility to be adapted to the needs of most applications. While there are many applications that require the high stiffness, thrust capacity and absolute accuracy of ball screws. Key Words: Lead screw, ball screw, threads, efficiency, accuracy, friction 1. INTRODUCTION 1.1. Lead screw Lead screws are threaded rods that are fitted with a nut. There are many types of threads used, but commonly used in industry is the Acme lead screw. Because the ACME thread is an industry standardized thread style, it is easily interchanged with parts from various manufacturers. The basic function of a screw is to convert rotary input motion to linear output motion. The nut is stationary and as the screw rotates, the nut moves forward and backward. Lead screw drive systems are available in a variety of sizes and tolerances. Contact is primarily sliding, resulting in relatively low efficiency and a wear rate proportional to usage. 1.2. Details of lead screw i. Lead screws can operate at 100% duty cycle at light loads and moderate speeds, or they can run at lower duty with either high load and low rpm or low load and high rpm, but not both. ii. Lead screw has more backlash as compared to ball screw. iii. The previously referenced PV factor is the product of the pressure and velocity between the nut and screw. It helps to determine the load, speed and duty cycle that the nut can handle. iv. Lead screw is to move the turret lathe by a précised increment for every rotation of the screw. As a result of this it allows the machine to generate threads on a work piece and helps in generating precise dimensions, and also to maintain a constant rate of metal removal. Fig. 2. Lead Screw 1.3. The advantages of a lead screw are as follows i. Large load carrying capability ii. Simple to design. iii. Easy to manufacture and no specialized machinery is required. iv. Precise and accurate linear motion.