Causes And Preventive Measures Of Surface Stars in Stamping Parts

Stars on the surface of stamping parts refer to the tiny convex hulls that appear on the surface of large-scale covering parts during stamping production. When checking the appearance quality of stamping parts with oilstone, tiny bright spots on the surface can be seen. These tiny defects can cause messy, irregular reflections of light after painting and affect the appearance quality.

The main reasons and preventive measures for stamping parts to produce surface stars

Details

Stars on the surface of stamping parts refer to the tiny convex hulls that appear on the surface of large-scale covering parts during stamping production. When checking the appearance quality of stamping parts with oilstone, tiny bright spots on the surface can be seen. These tiny defects can cause messy, irregular reflections of light after painting and affect the appearance quality.

The main reasons for the surface stars of stamping parts are:

①The surface of the raw material is dirty due to the surface of the material is not clean or the cleaning oil is not clean;

②The surface of raw materials is dirty due to poor preservation or long-term storage of materials after uncoiling and blanking;

③The mold is not cleaned or the mold is not cleaned in time, which causes the mold surface to be dirty;

④The surface of the base metal is dirty before the raw material is hot-dip galvanized;

⑤The chrome-plated layer on the surface of the mold is damaged after long-term production, and the surface of the material is dezincified due to the friction between the mold and the surface of the material during drawing;

⑥ The dustproof conditions of the production workshop are not good, and there is dust falling on the surface of the material and the surface of the mold at the production site;

⑦When carrying out handling production, when workers wear ordinary protective gloves, the dander generated by the friction between ordinary protective gloves and sheet material falls into the surface of the material and the surface of the mold;

⑧ The cutting powder produced in the trimming and punching process enters the mold.

In the stamping production process of large-scale covering parts, the position of surface stars is generally not fixed. The problem of surface stars is a difficult point in stamping production. The most serious case of surface stars in the production process is that more than 20 stars appear on the surface of one part. For the purpose, the rework time is 10 min/piece. Reducing and eliminating the surface star problem in stamping production, thereby reducing the repair rate and repair man-hours are the key control items in stamping production.

Precautions for reducing and eliminating star formation in stamping parts:

① The BL material (uncoiled blanking material) used for stamping production must be cleaned 1︿2 times, and the surface quality after cleaning must meet the requirements of the inspection standard;

② The material after uncoiling and blanking should be used for stamping production in time. If it cannot be used for stamping production temporarily, it should be properly handled in the process of transportation and storage to prevent the BL material from being soiled;

③ Stamping dies, especially drawing dies, must be cleaned. If there is dust and other dirt falling on the surface of the die during stamping production, the line must be stopped and the surface of the die must be wiped clean with a sticky cloth;

④ In the case that the surface of the mold and the material are clean, if the surface of the part still has serious stars after drawing, this material cannot be used for the production of large outer cover parts, and the material supplier needs to be notified to solve it;

⑤ The mold must be chrome-plated after a period of use;

⑥ Find a way to close the stamping workshop and production line for the production of large-scale covering parts to prevent dust and other contaminants from floating into the stamping line;

⑦If the large-scale cover is produced on the manual production line, the operator must wear special cut-resistant gloves when carrying out the loading and unloading operations;

⑧ Take measures from the mold structure to prevent the cutting powder from being generated, do not let the cutting powder enter the mold, and do not press the cutting powder. The material of the cut part is reduced by 2 times of tearing. As shown in Figure 3, a blowing pipe is designed and installed in the mold, and the cutting powder is blown out of the mold with compressed air.