The selection method of precision ball screw nuts for medical devices involves the consideration of several key parameters，To ensure that the selected lead screw nut meets the specific needs of the medical device。The following is a detailed selection guide：

one、Determination of accuracy

• accuracy level：Medical devices usually require high precision motion control，Therefore, the precision grade of the ball screw nut is the primary consideration。Accuracy class is generally defined as length300mmThe length variation of the ball screw。According to actual demand，Select the appropriate accuracy level，Such asC3（±0.008mm）、C5（±0.018mm）Etc.。For high precision medical devices，Recommended selectionC3Or higher precision ball screw nut。

two、Select the nominal diameter and lead

• Nominal diameter：The outside diameter of the ball screw is the nominal diameter，Proportional to the load capacity。Common specifications include12、14、16to63mmEtc.，But be warned，Not all diameters are available，Some diameters may need to be customized。For medical devices，A moderate diameter is recommended、Specifications that meet load requirements and are easy to install，Such as16~63mmamong。

• lead：The lead is the pitch，Is the linear movement distance of the nut per rotation of the screw。Common leads are1、2、4to40mmEtc.。The choice of leads should take into account the relationship between the linear speed and the input speed，Larger lead，The faster the input speed。For medical devices requiring high speed feed，Ball screw nuts with larger leads can be selected。

three、Consider load and rigidity

• Load capacity：According to the actual load requirements of medical devices，Select ball screw nuts with adequate dynamic and static load ratings。The rated load is not the maximum load，The smaller the ratio between the actual load and the rated load，The higher the theoretical life of the ball screw。

• rigidity：The rigidity of the ball screw shaft has an important influence on the precision positioning accuracy and the responsiveness of the control。Select the ball screw nut with good rigidity，The stability and accuracy of the system can be improved。

four、Definite nut form

• Nut form：Ball screw nuts come in many forms，Round flange、Single cut flange、Double cut flange and no flange, etc。Select the appropriate nut type based on the installation environment and performance requirements。In the case of frequent movement and high precision maintenance，Double nuts are recommended for increased rigidity and stability；On other occasions，Single side nuts can be selected to reduce cost and weight。

five、Consider other factors

• Mounting dimension：Based on the actual installation space of the medical device，Select the appropriate ball screw nut length and flange size。Note the difference between effective thread length and total length，And the needs of the shaft end processing form。

• Manufacturing method and preloading grade：The main manufacturing methods of ball screw nuts are rolling and grinding，Grinding accuracy is usually higher than rolling。The choice of preloading grade is based on the diameter、Double nut、Accuracy and driving torque and other factors are comprehensively considered。

• Temperature and life：The operating environment of medical devices may involve temperature changes，The effect of temperature on the life of the ball screw nut should be considered。Selective high temperature resistance、Wear resistant material and suitable preloading grade，Can extend the service life of the ball screw nut。

To sum up，The selection of precision ball screw nuts for medical devices should consider the accuracy level comprehensively、Nominal diameter、lead、Load capacity、rigidity、Nut form、Mounting dimension、Manufacturing method、Preloading grade and several factors such as temperature and life。Through careful comparison and selection，This ensures that the ball screw nut selected will meet the specific needs of the medical device。