What polishing thickness is required to achieve a roughness of less than or equal to 0.73
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For the cylinder bodies of pressure vessels designed recently, the required roughness level is Ra≤0.73; what thickness of polishing is needed to meet this requirement?
After multiple rounds of polishing, the surface roughness of the workpiece can reach level 12 or higher. The process involves grinding step by step using sandpapers of different roughnesses, as well as modifying the surface of the workpiece with flexible polishing tools, abrasive particles, or other polishing media. Polishing does not improve the dimensional accuracy or geometric precision of a workpiece; rather, its purpose is to achieve a smooth surface or a mirror-like finish, and sometimes it is also used to eliminate gloss (matting). A polishing wheel is usually used as the polishing tool. A polishing wheel is generally made by stacking multiple layers of canvas, felt, or leather, which are held together at both sides by metal discs; its edge is coated with a polishing compound composed of finely ground abrasives and oils mixed evenly. During polishing, the high-speed rotating polishing wheel (with a circumferential speed of over 20 meters per second) presses against the workpiece, causing the abrasives to roll and slightly cut the surface of the workpiece, thereby producing a smooth finished surface. The surface roughness can generally reach Ra0.63 to 0.01 microns; when non-greasy matting polishing agents are used, the smooth surface can be matted to improve its appearance. When producing bearing balls in large quantities, the drum polishing method is often used. During rough polishing, a large number of steel balls, lime, and abrasives are placed in an inclined drum-shaped container. As the drum rotates, the steel balls and abrasives roll and collide randomly inside the drum, thereby removing protrusions from the surface and reducing its roughness; this process can remove about 0.01 millimeters of material. During fine polishing, steel balls and pieces of fur are placed in a wooden barrel; continuous rotation for several hours yields a brilliantly shiny surface. The polishing of precision linear scales is carried out by immersing the surface to be polished in a polishing solution, which is composed of chromium oxide micro-particles with particle sizes ranging from W5 to W0.5, along with an emulsifier. The polishing wheel is made of finely textured, degreased wood or specially designed fine felt, and its movement follows a uniform and dense grid pattern. The surface roughness after polishing is no more than Ra0.01 microns, and no surface defects can be detected under a microscope at 40x magnification. There are also methods such as electrolytic polishing. Finally, polish it with a cloth wheel.
A roughness of 0.73 should correspond to a rough polishing; I’m not sure if polishing by 0.1mm will achieve that level
For polishing, the roughness is primarily determined by the equipment and the skill level of the workers, rather than the thickness being polished. For example, using a soft grinding disc or a hard grinding disc with a angle grinder will inevitably result in different levels of roughness.
Why is the value 0.73? ? ? As long as professional polishing equipment is available, it’s easy to achieve this; our tests showed that a value of 0.2 is no problem at all – all that’s needed is one rough polishing pass and one fine polishing pass. Also, if the raw material has already been drawn, polishing will be simpler.
As requested by the customer; thank you for providing the reference data
It must be a major foreign client. . . The domestic roughness is 1.6 ； 0.8 ； 0.4 ； A level of 0.2 micrometers. When doing the fine polishing, use a thousand-blade pad to move it evenly across the surface; pay attention to the pattern of polishing – just like mopping the floor, move back and forth in rows, so that the finish will be neater and more attractive.
The customer has the money; is a roughness of 0.73 considered rough polishing?
Coarse polishing and fine polishing are relative terms; there is no need to define them. Similar to rough turning and finish turning. For ordinary lathes, precision turning can only achieve 1.6 ； However, many CNC machines abroad can achieve a precision of 0.4 for finishing tasks. 0.73 should be easily achievable with a regular polishing wheel. . . Before polishing, you can first select an area to test which power tool will be fast and effective enough to meet the requirements. . .
How thick it needs to be thrown to meet the requirements depends on the condition of your substrate