How can graphite molds be cleaned?

How can graphite molds be cleaned?

Generally, when the molding process is completed, dirt or residues (with certain chemical composition and physical properties) are often left on the graphite mold. For different types of residues, the final cleaning requirements are different. Resins such as polyvinyl chloride will generate hydrogen chloride gas, which will corrode many types of graphite mold steel. Other residues are separated from flame retardants and antioxidants, which can cause corrosion to steel. There are also some pigment colorants that can rust steel, and the rust is difficult to remove. Even general sealed water, if it is left on the surface of an untreated graphite mold for too long, it will also cause damage to the graphite mold.

Therefore, the graphite mold should be cleaned as necessary according to the established production cycle. Every time the graphite mold is taken out of the press, the pores of the graphite mold must be opened to remove all oxidized dirt and rust from the non-critical areas of the graphite mold and template to prevent it from slowly corroding the surface and edges of the steel. In many cases, even after cleaning, some uncoated or rusty graphite molds will soon show signs of rust again. Therefore, even if it takes a long time to wash the unprotected graphite mold, the appearance of rust cannot be completely avoided.

Generally, when using hard plastics, glass beads, walnut shells and aluminum pellets as abrasives for high-pressure grinding and cleaning of the surface of graphite molds, if these abrasives are used too frequently or improperly, this grinding method will also cause problems. Porosity occurs on the surface of the graphite mold and residues are easy to adhere to it, resulting in more residues and wear, which may lead to premature cracking or flashing of the graphite mold, which is more unfavorable to the cleaning of the graphite mold.

Now, many graphite molds are equipped with “self-cleaning” vent pipes, which have high gloss. After cleaning and polishing the vent hole to achieve the polishing level of SPI#A3, perhaps after milling or grinding, the residue is discharged to the garbage area of ​​the vent pipe to prevent the residue from adhering to the surface of the rough rolling stand . However, if the operator chooses coarse-grained wash pads, emery cloth, sandpaper, grinding stones, or brushes with nylon bristles, brass or steel to manually grind the graphite mold, it will cause excessive “cleaning” of the graphite mold. .

Therefore, after searching for cleaning equipment suitable for graphite molds and processing techniques, and referring to the cleaning methods and cleaning cycles recorded in the archive files, more than 50% of the repair time can be saved, and the wear of the graphite mold can be effectively reduced.