How to measure the roughness of equipment polishing

Advantages of electrolytic polishing and mechanical polishing (1) Mechanical polishing is a process in which the surface to be polished is ground and deformed to achieve a smooth surface. In this way, a layer of cooled and hardened deformed layer forms on the surface of the part, along with some polishing abrasives; electrolytic polishing, on the other hand, is a process in which the surface to be polished is smoothed through electrochemical dissolution. No deformation layer is formed on the surface, nor are any foreign substances trapped there. Additionally, the oxygen released during the electrolysis process results in the formation of an oxide layer on the polished surface, further enhancing its corrosion resistance. (2) For parts with complex shapes, wires, thin sheets, and small components, mechanical polishing presents significant processing difficulties, whereas electrolytic polishing offers excellent processing capabilities. (3) Mechanical polishing followed by electro-polishing further improves the reflectivity of the part’s surface. (4) Electro-polishing smooths the surface and removes inclusions on it. Thus, the electron cold emission of the metal decreases. In addition to being widely used to reduce the surface roughness of parts and improve their brightness, electropolishing can also be employed to extend the service life of cutting tools ； It displays defects on the surface of the part, such as cracks, sand holes, and inclusions.

There are various types of polishing methods, including manual polishing, electrolytic polishing, ultrasonic polishing, extrusion honing polishing, and polishing using mechanical devices. However, for mold cavities with complex shapes as well as for the final finishing process, manual polishing remains the primary method used at present. The following focuses on manual polishing. Polishing is a method that removes metal by using a medium and tools to move the free abrasive particles on the surface of the workpiece. Different methods result in varying degrees of metal removal; in other words, their efficiency and the level of roughness that can be achieved on the surface of the mold cavity after polishing differ. The following table shows the economic machining allowance for this process (in mm), as well as the roughness level achieved after processing (in μm): Coarse polishing: 0.05–0.15, 0.2–0.8; Fine polishing/mirror polishing: 0.005–0.01, 0.001–0.1; Electrolytic polishing: 0.1–0.15, 0.025–0.8; Ultrasonic polishing: 0.02–0.05 (precision), 0.1–0.15 (coarse), 0.01–0.1. Factors that affect the quality of mold polishing include the skill of the operator. The operator’s skill refers to the ability to control the three elements of force (magnitude, direction, and point of application) as well as the duration of application during polishing. A. In manual polishing, when the direction of the force applied to the mold cavity varies, the speed at which debris is removed from different points on the surface to be polished also changes, which in turn affects its surface quality. To remove the pits on the surface of the mold cavity, the direction of the force applied during polishing should be varied in order to increase the chip removal rate at those areas, which helps to eliminate the pits on the mold cavity surface ； To eliminate the bulges on the surface of the mold cavity, the direction of the force applied during polishing should be perpendicular to the surface of the mold cavity being polished, in order to increase the chip removal rate at its center and thus remove the bulges on the surface. In manual polishing, the direction on the surface of the mold cavity where the force is greatest results in a faster chip removal rate; therefore, the magnitude and direction of the force also affect the polishing quality of the mold cavity. The pressure applied during polishing is roughly equivalent to the force used when gently pushing with the tip of a finger. If the pushing force is too great, it will leave marks on the surface of the workpiece and also reduce the shape accuracy. B. In manual polishing, if the application of force lasts for too short a time – that is, if the residues from the previous polishing step are not removed before moving on to the next step – the result of the polishing will certainly be unsatisfactory ； If the application time of the force is too long, it will increase the cost and may also cause the \"orange peel\" effect; therefore, the application time of the force also affects the polishing quality of the mold cavity. According to Japanese experts in grinding, the performance of abrasives implies the presence of grinding materials, where “materials” refers to substances such as wood, raw materials, and processed items. However, in grinding processes, abrasives are made from materials such as diamond powder or aluminum abrasives, as well as sandpaper; therefore, both of these substances can be referred to as abrasives. The hardness of the abrasive. The hardness of the abrasive is one of the most important factors determining its polishing performance. The higher the hardness of the abrasive, the stronger its polishing ability. The so-called polishing ability refers to the cutting capacity of different types of abrasives with the same particle size under identical process conditions. Grain size of the abrasive. In actual production, abrasives are composed of particles of varying sizes within a certain range; their shape and size are well-organized, and they do not react with the workpiece. These particles include very coarse grains, coarse grains, medium-sized grains, mixed grains, and fine grains. Among them, the very coarse and coarse grains have the greatest impact on the quality of the abrasive, while fine grains play only a minimal role in the cutting process during polishing. To improve the polishing ability of abrasives, increasing the number of their primary particles is an effective method. The smaller the particle size of the abrasive, the higher the surface quality that can be achieved after polishing. Table 2 lists the particle size of the abrasive. The most commonly used abrasive medium is diamond abrasive, which is classified by the size of its sieve pores; the higher the number, the finer the sand particles. Table 3 lists the common sizes of polishing abrasives.

I understand the principle, thank you! But I wonder, how exactly can experts use the naked eye to distinguish between a 0.2 and a 0.3 polished surface?

Who could distinguish between 0.2 and 0.3 with the naked eye? Just ask the contractor to bring their own roughness tester

Thank you, thank you! Thank you for providing the information.

I’ve learned a lot~:) Thanks for providing the information.

Roughness can be measured with the naked eye! ! ! ! ! ! ! ! ! ! ! ! ! ! ? ?