The Ball Screws must be aligned before assembly to control the runout. It is calibrated to the corresponding runout value according to the accuracy level of the Ball Screws. The hydraulic and servo alignment processes are both cold alignment processes and It is qualified only if it jumps when shipped. As time goes by and the stress is released during transportation bumps, the Ball Screws will slowly rebound to the state before straightening.

 We use a thermal alignment process to internally control the runout within 0.015mm even for the cold-rolled Ball Screws, while the ground screw will control smaller runout based on the accuracy level.

The Linear Actuator parts material and heat treatment are the basic guarantees for high-quality Ball Screws and Planetary Roller Screw. We obey the superior alloy steel and the molding process must be spraying, not casting. Strictly required to use a two-ball, two-draw process, and the eutectic carbide must reach level 1 for Ball Screws Assemblies.

After the materials need to be undergone a cold pressing process similar to "forging" to further optimize the metallographic structure.

The cold-rolled screw blank diameter also needs to implement a self-developed hard rolling process to minimize the heat treatment deformation for Ball Screws Linear Actuator.

The cold-rolled screw rolling machine is a key for manufacturing Ball Screws and Planetary Roller Screw.Most manufacturers use "dovetail rail" structure thread rolling machine. The "dovetail rail" needs to be added with "shims" to adjust the matching clearance. The defect is it cannot be pushed axially if it is locked, and there will be radial deflection if the lock is loose, the Ball Screws Assemblies will have "black and white circles", the Ball Screws will have inconsistent contours and roundness, and the assembly nut will have "one circle is tight and one circle is loose".

The radial drive of the thread rolling machine generally adopts hydraulic drive, and the floating nature of the holding pressure determines the consistency of the screw pitch diameter.

We launch two structures: Rexroth hydraulic system and servo drive according to different screw requirements; The transmission mechanism adopts ground trapezoidal screw and ground Ball Screws are respectively configured in hydraulic thread rolling machines and servo thread rolling machines. The above measures can reduce the impact of unstable driving on the precision of the cold-rolled screw.

The internal thread grinding datum affects the taper of the thread busbar,the neutrality, the parallelism of the internal thread busbar and the outer diameter of the nut, and the runout of the internal thread busbar and the nut flange datum end face.

The internal thread, external circle, and end face compound grinder can control the parallelism of the internal thread and the external circle, and can also control the perpendicularity of the internal thread and the flange surface. When the roundness and taper of the nut bottom hole are controlled by the previous process, there is a deviation in roundness and taper, the tooth height will be inconsistent and the contact angle will deviate. When flange nuts are used more, the flange needs to have a certain thickness, otherwise there will be no clamping position, and the Miniature Ball Screws pair basically does not have the conditions for the compound grinding.

In the clamping method adopted by most manufacturers, the nut thread busbar cannot be centered relative to the reference line and is not vertical relative to the flange surface. The side pin can only control the consistency of the nut but cannot control the consistency of the thread starting line relative to the position of the returner hole.

In addition to controlling the above problems for Ball Screws Linear Actuator, we also configure a 60,000+ high-speed dynamic and static piezoelectric spindle, a self-made anti-vibration grinding wheel rod, supplemented by nut fairway polishing technology. The roughness is less than or equal to Ra0.1, and the smoothness exceeds that of our peers.

Regardless of external thread or internal thread grinding, the grinding roughness is roughly Ra0.8. The conventional method is to use the running-in process to reduce the friction coefficient of the contact angle spiral. After running-in, replacing the steel ball actually changes the contact angle spiral that does not play a fundamental role in the case of high-precision heavy pre-loading.

Our ground Ball Screws and nuts have passed the global grinding technology to control the roughness of the screw pair between Ra0.05-0.1, which greatly improves the softness and transmission efficiency, and has an oil storage function.

The roughness of cold-rolled Ball Screws rod before heat treatment can be within Ra0.2, but the heat treatment deformation and oxide scale change the roughness, and the polishing process cannot restore the state before heat treatment.

The deformation during the pre-treatment process is less than our competitors. The hard and cold rolling process also aims to avoid heat treatment deformation as much as possible. We use a self-made special machine for polishing to repair the micro-deformation of the fairway during heat treatment and reduce the roughness of the Ball Screws fairway.

In order to facilitate the processing of the shaft end, most manufacturers anneal the screw rod and then process the shaft end. However, during annealing, the threaded fairway near the annealed end will be deformed. After annealing, the oxide scale needs to be polished with a fiber wheel, which will also change the size of the threaded fairway. The hardness of the central shaft end and the threaded part are different, the stress relief is inconsistent, and the screw rod slowly deforms slightly.

We always use non-annealing hard turning technology from beginning to end. Although the producing cost of Precision Ball Screws will be increased, the quality come first for our believe.