The quality cultivation of new car model molds has been completed, and facing the large-scale production increase of car models, in order to avoid the impact of mold fuzzing on production, major automobile manufacturers now carry out chrome plating treatment on the surface of the molds after the quality cultivation of the molds is completed, to maintain the stability of the stamping parts size, reduce the frequency of mold maintenance, and ensure the timely mass production and launch of new car models.
The meaning and function of mold electroplating. The so-called hard chromium electroplating refers to a hardness of HV800 (HRC64 °) or higher and a film thickness of 10 μ or more. Almost all mold materials can be electroplated. However, electroplating lacks unique uniform electroplating properties, and managing film thickness is also very difficult. The precipitation process of electroplating is shown in Figure 1, where a specific voltage and current density are used to carry out an oxidation reaction on the anode, while generating oxygen gas; Inducing a reduction reaction on the cathode, producing hydrogen gas, thereby precipitating chromium.
Before leaving the factory, the production workshop needs to build a permanent inventory according to the production plan to meet the 7-day production demand, which is 2 to 3 days longer than the electroplating cycle, in order to avoid abnormal events during the electroplating period. Before electroplating, it is important to conduct the following mold inspections and confirmations: 1 The surface of the mold should be polished and polished, with a roughness of less than Ra0.4. 2. It should be ensured that the quality of the stamped products is stable, and the parts are free of defects such as cracking, wrinkling, and deformation of the surface. The number of stamped pieces should be greater than 10000. 3. Pre plating treatment should be carried out according to the surface contact of the stamped parts to prevent small gaps between the inserts, black surfaces on the flanges, and broken parts. 4. It is necessary to confirm the areas where stamping parts are prone to burrs, scratches, burrs, and cracking. If any of the above situations occur, they should be repaired in a timely manner. 5. In the early stage of electroplating maintenance, it is generally not allowed to have welding parts. In special circumstances where welding needs to be repaired, welding rods with less nickel content should be used for the welding parts and materials, otherwise it may cause poor electroplating or poor bonding with the base material. It is recommended to use the following welding rods: a. TM2000B welding rod for flat position, b. Ea600 welding rod for blade position, c. MH-100S welding rod for drawing position to ensure the quality of electroplating at the welding point. During the maintenance and inspection stage before the mold leaves the factory, personnel from the electroplating manufacturer can be invited to guide and confirm on site to ensure better electroplating quality. Before electroplating, customers should remove the following accessory components:; a. Cylinder and air pipe of the top material plate b. Mold identification plate; c. Balance block and guide plate d. Positioning plate and blocking plate 7. Before electroplating, inform the electroplating manufacturer in advance of the name, size, area, and delivery time of the factory mold to facilitate vehicle arrangement. Mark the vulnerable and defective parts of the mold and notify the electroplating manufacturer; To facilitate early technical communication and exchange. 2. Pre electroplating inspection work This part of the work is carried out by the electroplating factory, which confirms the status of the mold when it enters the factory. This stage of work is the execution of electroplating and is the key to the quality of electroplating. 1. Confirm and take photos of the main parts for archiving, contact the customer for confirmation, and ensure that the mold is repaired and processed in a timely manner. 2. Degreasing and washing to remove oil stains and dust from the surface of the mold. 3. Chromium removal treatment, if the mold is subjected to secondary electroplating, the previous electroplating layer of the mold should be removed before the mold is electroplated again. If it is the first electroplating, the secondary step does not need to be done. 4. Check and repair the key parts of the mold that need to be electroplated for defect inspection and repair, especially evaluate and repair the welding joints and problem points in production engineering. 5. Grinding before electroplating mainly removes rust and oxides on the surface of the mold, increasing the smoothness and adhesion of the coating after electroplating. 6. Anode setting and electroplating: Anode setting is one of the most important steps in whole chrome plating. Based on special processes and advanced technology, professional anodes and auxiliary anodes are developed for mold characteristics to ensure the uniformity and adhesion of the coating on the mold. After electroplating, polish/polish to remove the fine and rough "chromium nodules" and dirt on the surface of the electroplated mold, and improve the surface smoothness of the mold as shown in the figure.