Carbonized black lines on the product surface

In the '2079851475616104458 (vacuum forming) production process, the product exhibits the quality defect of "Carbonized black lines on the product surface".The specific manifestation is Black carbonized line-like impurities appear on the product surface.This defect is more common when processing materials such as PP, PS, PET, PVC and ABS sheets, and its occurrence is usually related to unreasonable settings of sheet heating temperature, forming pressure/vacuum, mold temperature and cooling time.When the Carbonized black lines on the product surface situation is severe, it will cause a series of chain quality defects in the product's appearance, dimensional accuracy, mechanical properties and other aspects, which not only reduces the product's functionality and safety in use, but also directly increases the scrap rate and production cost.Therefore, this problem requires systematic diagnosis and optimization from multiple dimensions such as material selection, the status of the '2079851475616104458 machine, heating oven, mold and vacuum/air pressure system, and sheet heating temperature, forming pressure/vacuum, mold temperature and cooling time.

1. Carbonized impurities in the sheet.The mixing of foreign matter will destroy the homogeneity of the melt, causing defects such as spots, voids and stress concentration in the product.These foreign matters may come from the raw material itself, residues in regrind, equipment material accumulation falling off, or pollutants in the production environment.Strengthening raw material purification management and equipment cleaning is the key to preventing foreign matter from mixing in. 2. Carbon deposits on the mold surface.The mold is the core tool that gives the product its shape and surface quality.Unreasonable mold design, such as improper runner/gate dimensions, insufficient venting and inadequate draft angle, will directly lead to forming defects.The machining accuracy, surface treatment quality and daily maintenance status of the mold also directly affect product quality. In addition, the insufficient overall coordination of sheet heating uniformity and stretch ratio control is also a factor that cannot be ignored; there are complex interactions and coupling relationships among the process parameters, and the deviation of any parameter may aggravate the degree of Carbonized black lines on the product surface through chain effects. In terms of equipment maintenance, the regular overhaul and accuracy confirmation of the '2079851475616104458 machine, heating oven, mold and vacuum/air pressure system are not in place, causing the actual operating parameters of the equipment to deviate from process requirements, which will also become a potential inducement of the Carbonized black lines on the product surface problem.

1. Check sheet quality.Inspection work should establish a standardized checklist, specifying inspection items, technical standards, inspection frequency and responsible persons.Key equipment components should be regularly disassembled to check the condition of hidden parts, and judgment should not be based solely on operating appearance.Inspection results should be recorded in detail and a trend analysis mechanism established to predict potential failures. 2. Clean the mold.Cleaning work should be incorporated into the equipment preventive maintenance plan, and the cleaning frequency should be reasonably determined according to the actual conditions of the processed material and operating cycle.Use dedicated cleaning tools and cleaning materials to avoid scratching or electrolytic corrosion of the cavity surface caused by improper operation.After cleaning, re-check and confirm that the key clearances are accurate. It is recommended to formulate a preventive checklist for the Carbonized black lines on the product surface problem, incorporate sheet heating uniformity and stretch ratio control into the daily inspection scope, and conduct online monitoring of key parameters through the SPC statistical process control method to achieve early warning and rapid response to problems. In terms of material management, incoming inspection of raw materials and in-process testing of work-in-progress should be strengthened, and key performance indicators of PP, PS, PET, PVC and ABS sheets should be strictly controlled to ensure the stability of forming quality from the source.

In summary, the causes of the "Carbonized black lines on the product surface" problem can be attributed to the combined action of multiple factors such as Carbonized impurities in the sheet, Carbon deposits on the mold surface.To solve this problem, it is necessary to start from aspects such as Check sheet quality, Clean the mold and take systematic governance measures.In actual production, it is recommended to establish a prevention and rapid response mechanism for this problem, achieving stable production and continuous improvement through sheet heating uniformity and stretch ratio control.