Ball screw is core component of precision linear transmission system. The positioning accuracy, operating noise, service life and stability of the equipment all depend on whether the installation process meets standard. Compared with trapezoidal screws, ball screws has higher precision, smaller clearance and more refined structure. They require strict compliance with requirements for coaxial, parallel, preload and installation methods. Any installation deviation will directly lead to inaccurate positioning, high-speed vibration, abnormal noise, overheating, blockage and other problems, seriously affecting the service life. Based on general industry installation standard, this paper summarizes the complete installation steps, key points and key taboos of ball screws to help equipment manufacturers and maintenance personnel realize standardized assembly.
I. Pre-installation Preparation and Precision Inspection
Cleaning and checking before actual assembly constitutes the first step in ensuring accuracy, but this is often the most overlooked critical phase. First, clean installation surfaces (such as machine tools, bearing housing and support units) and the screw itself to remove metal chips, oil, dust and impurities completely. Precision screws must be free of particulate contaminants to prevent raceway scratches or ball damage during operation. Next, verify the screw model, length, thread specification and preload grade to ensure consistency with the operation of the equipment. Check the nut exterior for dents, deformation or raceway damage and manually slide the nut along the entire length to ensure smooth movement without adhesion or abnormal resistance. Finally, prepare the necessary tools-such as dial indicator, spirit level, torque wrench, and special fixtures-to avoid rough handling and lay the groundwork for high-precision assembly.
ii. Mounting Support Units and Bearing Assemblies
When installing the ball screw, the support structure at both ends should be fixed as a priority to ensure coaxial and stability during operation. Setup configurations are selected based on device structure, and common configurations include "fixed support," "fixed support," and "support." High-speed, high-precision equipment needs to be ``fixed ''. First assemble the bearings, seals and bushing in the correct order at the end of the screw shaft to ensure that the bearings are in the correct position and not tilted or misplaced. The support units at each end are then mounted on the reference surface of the machine frame; only the screws are gently tightened at this stage to allow for minor adjustment for subsequent parallelism and straightness adjustments. When assembling bearings, do not slam or force; this will deform the steel balls and damage the preload.
III. Position and parallel alignment of ball screw (Critical Step)
Parallel alignment determines the equipment's long-term operational accuracy and is the most critical part of the installation process. Carefully place the ball screw into the support blocks at each end, then install the coupling and connect the servo motor to ensure that the motor shaft and screw shaft remain concentric. Measure the runout errors at both ends and in the center of the screw by using a dial indicator mounted on the sliding table and align the screw parallel to the straight guide rail. The industry standard requires that parallelism errors of high precision equipment be limited to 0.01 mm and that the parallelism error of standard automation equipment be limited to 0.03 mm. Error is too big, easy to cause operation adhesion, uneven loading, uneven nut wear, high-speed vibration. After alignment, gradually tighten the mounting screws on the support block in diagonal mode to prevent deformation caused by tightening the side first.
IV. INTRODUCTION Nut Housing Assembly and Load Centering
After aligning the body of the ball screw, install the nut housing to the sliding workbench. Slide the screw nut to the midpoint of the stroke- making sure the load is evenly distributed- then match it to the countertop mounting surface and gently tighten the retaining bolts. Never tighten the bolt completely when the nut is dislocated, tilted, or subjected to uneven forces, as this will expose the nut to radial loads. Once assembled, manually slide the workbench across its entire range of motion to check for consistent sliding resistance and to ensure that there is no adhesion or resistance fluctuation. If the local resistance is not normal, it indicates a a centering misalignment; the position of the nut housing must be fine-tuned to ensure that the nut receives only pure axial thrust and eliminates radial off-center loads.
V. Coupling Connection with Motor Coaxiality Alignment
The dislocation between motor and screw is the main cause of abnormal noise, vibration and shaft breakage. When installing coupling, ensure that the motor shaft and screw shaft are highly concentric, with even clearance at the end and no eccentricity. Measure the coupling's radial and axial (end-face) runout using the dial indicator to ensure that deviations remain within industry-acceptable range. In order to prevent AC torque from being generated during transmission, it is forbidden to force adjustment or assembly of excessive tension or pressure. After accurate alignment, tighten the joint screw evenly to ensure no loosening, no sliding, so as to ensure smooth, lossless power transmission.
VI. INTRODUCTION Trial Run, Lubrication and final acceptance
After the structural assembly is completed, it cannot be operated at high speed immediately and must be carried out in accordance with the standard commissioning procedure. First, manually rotate the leadscrew to ensure smooth movement throughout the trip, making sure there is no binding noise or abnormal noise. Secondly, carry out low speed, emptyload test, in monitoring vibration, noise, temperature rise at the same time, gradually speed up the test. After the successful test run, specialized leadscrew grease applied to ensure that the raceways and steel balls are fully lubricated to minimize friction and wear. Finally, a repeated positioning accuracy test is carried out to confirm the accuracy of the action, no gap, no deviation, thus completing the overall installation acceptance.
FAQs: FAQs
Question 1: What are the biggest taboos in ball screw installation?
A: Forcible assembly, installation under centrifugal load and violent hammering are strictly prohibited. Ball screw should not be affected by radial forces, it can not meet the standard of coaxial degree and parallelism, which will shorten service life and even directly damage the raceway structure.
Q2: After installation, what unusual noise will be made during use?
A: This is usually due to coaxiality deviation, uncorrected parallelism, insufficient lubrication, dust ingress, or steel ball misalignment. Must be shut down and readjusted, lubricated, and the leadscrew cleaned.
