How are Ball Screws Different from Standard Lead Screws?

Ball screws and lead screws are not interchangeable in many cases, always need to consider about the precision, stiffness and load capacity. The specifications and performance may not correspond to each other completely. Recently, many customers were doubtful to distinguish the lead screw and ball screw, then what are the difference? Here kos factory carefully explain it to everyone in order to avoid unnecessary trouble in the purchase or use in the future.

The difference between the standard leads screw and ball screws are mainly different structure, different working principle and different product characteristics.

Different structure of lead screw and ball screw

The structure of the lead screw is simple, not complicated. It is mainly composed of screw and nut. The installation is simple and convenient, but lower accuracy.

The ball screw is composed of screw, nut, steel balls, preload sheet, reverser, dust-proof device, complicated structure, high installation requirements, but high precision and has gradually replaced the use of lead screw.

Lead Screw Vs. Ball Screw

Different working principles of lead screw and ball screw

The working principle of lead screw as follows: lead screw is utilize the oil slick between the nut and the screw to produce relative sliding motion, use the sliding friction to complete the linear motion.

The working principle of ball screw: when the screw is used as active body, the nut will convert into the corresponding pitch of linear motion with the screw rotating. The passive workpiece can through the connection of nut bracket and nut to achieve the corresponding linear motion.

Different characteristics of lead screw and ball screw

Lead screw characteristics are low cost, used in some machine tools with low accuracy requirements and other equipment, simple installation, simple structure, easy maintenance, and larger friction coefficient, the accuracy can not up to the higher standards.

Other difference of product characteristics:

1, Transmission efficiency. Ball screw transmission efficiency is about 90% to 96%, and the lead screw transmission efficiency is about 26% to 46%. That is, if driving the same loads, the ball screw can use smaller driving power, such as smaller power motor, can both reduce the cost and energy consumption.

2, Self-locking. Self-locking is inversely proportional to the transmission efficiency, therefore, the ball screw has hardly any self-locking, and the lead screw has a certain self-locking (depending on the lead angle and roughness of working surface). In general, the vertical use of ball screws need to increase the self-locking device.

3, Economical efficiency. From the previous and the current situation, the ball screw structure is more complex than the lead screw, so the price is still higher than the lead screw. However, with the increase in automation equipment and production increases, the price difference is getting smaller and smaller. And from the cost performance, at present, the ball screw is better than lead screw.

4, Transmission speed. Ball screw is rolling friction while the lead screw is sliding friction, the temperature rise of the former is much lower than the latter in working, so it can undertake the task of high speed transmission.

5, Service life. Rolling friction surface damage is much smaller than sliding friction, so in the same cleaning, lubricating and other conditions, the service life of the ball screw is much longer than the lead screw.

6, Accuracy. Ball screw is rolling friction, no backlash, can achieve precise positioning, the accuracy of ball screw is far from the lead screw can achieved. Only ball screws or linear motors can be used on CNC tools and high precision equipment.

Ball screw characteristics are low friction coefficient, fast dynamic response, easy to control and high accuracy. Ball screw in the production process, applied preload between the raceway and balls can eliminate the clearance, so the ball screw can achieve no backlash. It is widely used in CNC machine tools and other equipment that require high accuracy. But also have the features of higher price, higher installation requirements, and high maintenance costs.

The above is the essential difference between standard lead screws and ball screws, when you are purchasing or recognizing lead screws and ball screws, please make your choice according to your actual usage, in order to avoid overkill or high economic costs and other consequences.

sfu1605 ball screws

The original equipment manufacturer’s application system often requires the most suitable products, and the lead screws are often the right choice. Lead screw products are easily combined with specific applications to adjust to achieve the desired performance, while minimizing the cost. In some cases, life testing is required at the design stage, but for the original equipment manufacturer, such extra work in the early stages will help reduce the cost of the product. The ball screws can be continuously operated, bear much higher loads, and achieve faster speeds. Therefore, it is worthwhile to increase the cost for this purpose. For the end user, the ball screw has a good predictability, and therefore is the best choice to ensure rapid integration and reliability. For example, the plant automation system relies heavily on ball screw technology. Of course, there are many OEM systems that require ball screws, such as the machine tool industry. For the original equipment manufacturer, what determines technology is performance and cost, not predictability.

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