For plastic injection molded medical products such as tips and reagent cartridges, if continuous injection molding is performed, gas resin of plastic resin accumulates inside the mold. Due to poor gas escape in the plastic resin mold, fluctuations and voids are likely to occur in plastic injection molded products. In order to prevent fluctuations and voids from occurring in plastic injection molded products, to improve the non-defective product rate and to produce stable and good products, it is necessary to perform regular mold maintenance.

Medical plastic injection molded products, especially the tips with extremely fine at its apex part, the mold maintenance frequency is high and difficult, so care must be taken when handling the mold.