What Are The Differences Between Ground And Refining Ball Screws?

The key difference between grinding grade ball screw and machining grade ball screws lies the key dimensions of machining process, precision, application scenarios, cost, etc. The specific analysis is as follows:

1.Differences in processing techniques
Grinding grade: Spot by point processing of screw threads through precision grinding equipment. High hardness grinder is used for micro-cutting on the surface of the pin screw to form a high precision thread profile. The process enables surface roughness to the nanometer level (≤ 0.2 micron) and flexible adjustment of thread parameters (e.g. lead and tooth profile Angle).
Remanufacturing grade: using cold rolling or hot rolling process, metal billets plastic deformation through the mold, directly forming threads. The process is efficient, but due to mold limitation, the thread parameters have relatively small adjustment space and the surface roughness is generally Ra0.8 -1.6 microns.

2.Differences in precision grades
Grinding grade: Accuracy up to IT1-IT2 grade (international standard), lead error ≤0.005mm/m, axial clearance ≤0.003mm, suitable for high precision positioning (e.g. semiconductor equipment, optical instruments, etc.).
Conversion grade: Precision is usually IT5-IT7 with lead error ≥ 0.03 mm/m and axial clearance ≥ 0.01mm. Applicable to general machinery (such as ordinary machine tools, automation equipment, etc.).

3.Surface quality differences
Grinding grade: The surface has been multiple grinding and polishing processes, with uniform microtexture, low friction coefficient (μ≤0.003), excellent abrasion resistance and a service life 2-3 times that of the remade grade.
Grade: High friction coefficient with rolling surface (μ005 -0.01). After long-term use, it is easy to wear and tear, which leads to a decrease in accuracy.

4.Differences in stiffness and carrying capacity
Grinding grade: Due to the full release of stress in the material during processing, the screw has a high stiffness (axial stiffness can reach more than 500N/μm) and can withstand a high dynamic load (e.g. high-speed reciprocation).
Transfer rating: The rolling process may result in residual stress within the material, with slightly lower stiffness (axial stiffness approximately 300-400N/μm) and therefore suitable for low speed and heavy loading (e.g. lifting equipment).
V. Differences in costs and production cycles
Grinding grade: long processing cycle (multiple grinding and inspection processes required), high equipment and labor costs. Prices are typically 2 to 5 times higher than the redo grade.
Re-manufacturing stage: with high batch production efficiency and low unit cost, suitable for large-scale applications (such as standardized machinery and equipment).

6.Adapt to application scenarios
Grinding grade
High-precision requirements: such as CNC machine tools, precision instruments, robot joints;
High-speed operation: e.g., high-speed machining centers (spindle speed ≥ 10,000 RPM);
Long service life: such as aerospace, medical equipment, etc. (stable operation for more than 10 years).
"Transition level
General situation: such as ordinary lathes, automated production lines, logistics equipment, etc.;
Low-cost demands: such as household appliances, toys and simple drivetrains.

7. Differences in maintenance and reliability
Grinding grade: Due to high grinding accuracy, slow grinding speed, and long maintenance cycle (usually ≥5000 hours), repair costs are higher after grinding failure (requiring re-grinding or replacement).
Repairs: relatively short maintenance cycle (about 2000-3000 hours), but low replacement cost after failure, suitable for situations where downtime is not considered.