First, the production process of large specifications a […]
First, the production process of large specifications and large size O-rings
1.When selecting large size O-rings, pay attention to the following technical details
(1) Calculate the pre-stretch rate (piston seal) or pre-compression rate (piston rod seal), section shrinkage;
(2) Pay attention to the compatibility of the seal and the liquid to be sealed, and consider the swelling of the seal ring;
(3) Also consider the thermal expansion of the seal.
For example, piston seal: if the diameter of the seal groove is 780, then the inner diameter (including tolerances) of the seal you ordered must be at least 780 or less; if it is a piston rod seal: if the diameter of the groove is 780, then you ordered The outer diameter of the seal (including tolerances) must be at least 780.
2.Processing method of large-size O-ring
Large-size non-standard O-ring seal processing method and mold design. The upper and lower molds are used to design a long multi-cavity mold. The two ends of the mold are closed and disassembled to ensure high pressure vulcanization. The upper and lower molds can be installed at 30 to 250 ° C. Adjust the heating device, and install adjustable cooling devices with a temperature of 30 to 250 ° C at both ends of the upper and lower molds; assuming that the temperature of the upper and lower molds is between 150 and 220 ° C, close the upper and lower molds after dust removal and control the temperature rise; The non-standard O-ring wire diameter requires the preparation of a rubber strip with a determined width and height. The rubber strip is placed in the cavity of the upper and lower molds and closed, and the two ends of the upper and lower molds are closed and pressurized; the cured rubber is vulcanized. After the strips are taken out of the upper and lower molds, the vulcanization is continued. After the length of the rubber strips reaches the total length, the strips are sequentially docked until the completion of the trimming test after the entire O-rings are docked, so as to achieve the preparation of large-size non-standard O-rings.