TRADITIONAL MACHINES VENTS
One of the most common ways of adding venting is by manually machining it into the mold (Figs. 1-3). A parting-line vent is the most common type of machined vent. In this setup, the best location for a vent is opposite the gate, where the part gets filled last.
Another machined venting option involves grinding a small vent channel around the parting line, yet this method will only work with a limited number of resins and the channel must be thin enough not to flash. Still another area for traditional machined vents is around and down along ejector pins, which vent through the mold flats to the outside of the mold.
Traditional machined venting has certain limitations. Ejector pins and ground vents are in fixed positions and can't be moved if the venting proves to be insufficient. The size and locations of machined vents are sometimes the result of trial and error, which can add time and cost to your process. Machined venting can close off if not properly maintained. And finally, the complexities of machining vents in some locations—such as at the runner, at deep ribs, in corners, in thick fill areas, and at weld locations—present additional challenges.
The article comes from China injection mold manufacturer - Mold Best Assurance Company Limited, website is www.mbamoldanddesign.com
