Views: 0 Author: Site Editor Publish Time: 2026-09-27 Origin: Site
Steel ball production usually involves more than one finishing operation. After heat treatment, hard grinding removes a controlled amount of material and corrects the ball’s basic diameter and geometry. Lapping follows when the process needs tighter roundness, more consistent diameters within a lot or a finer surface finish.
The two operations should not be treated as interchangeable. A 3M7480 vertical steel ball grinding machine is positioned for hard grinding and precision grinding. The 3ML4780D vertical steel ball lapping machine is used for finishing lapping or superfinishing after hard grinding.
Give the supplier the full working range, not just one nominal size. Include the smallest and largest ball diameter, the incoming diameter, the required finished diameter and the allowance to be removed.
| Machine | Main process | Published working ball diameter |
| 3M7480 | Hard grinding and precision grinding | φ3–φ20 mm |
| 3ML4780D | Finishing lapping and superfinishing | φ3–φ25 mm |
A diameter range is a starting point for selection, not a promise that every material and process will reach the same output in the same time. Ball hardness, incoming geometry, allowance and target grade still need to be reviewed.
Also separate the ball’s end use from the machine’s working range. Some project specifications call for larger balls for drum-mill service and smaller balls for sand-mill service. The ranges φ20–φ50 mm and φ5–φ15 mm may appear in particular application notes, but they should be confirmed against the actual mill, material and process before being used as general rules.
Provide the measured hardness of the incoming balls, the hardness scale and the test method. A single target such as 180–220 HV should not be applied to every stainless grade and supply condition. Hardness varies with material, processing and work hardening, and the machine supplier needs the actual condition of the production batch.
“Stainless steel” or “bearing steel” is not enough information for a machine quotation. Provide the material grade and the condition of the balls entering the machine. AISI 52100 bearing balls, carbon steel balls and stainless steel balls can differ in hardness and finishing behavior. The process should be matched to the actual material rather than to a broad material family.
For stainless steel, AISI 304 is commonly described as an 18% chromium, 8% nickel grade. AISI 316L also contains molybdenum and is selected where its corrosion performance is needed. See RISHENG’s stainless steel balls and bearing steel balls pages for the product ranges.
A grinding machine removes a larger allowance and corrects ball size and basic geometry. A lapping machine performs a later finishing operation to improve roundness, diameter consistency and surface finish. The 3M7480 and 3ML4780D are designed for different stages.
The standard working diameter published for the 3M7480 is φ3–φ20 mm. A 30 mm ball is outside that stated range, so confirm a suitable alternative with the manufacturer before specifying the machine.
The 3ML4780D can be evaluated for stainless steel balls. The lapping plate, abrasive, pressure and speed should be confirmed for the specific grade, hardness and target finish.
No. Maximum batch load is the amount loaded for a process cycle. Finished output per shift also depends on cycle time, ball size, material, allowance, inspection and sorting.
No. Their densities are close. Material selection should follow the working environment and required corrosion performance. For equipment selection, provide the exact grade and ball condition so the grinding or lapping process can be reviewed.
