In plastics injection molding, sleeve ejector system usually use to create boss of product. Boss of product usually use to assemble two parts so it need good dimension, tolerance, appearance. If we don’t use sleeve ejector pin, product may be scratch, cracked, sink mark at boss or hole location.
I. Basic construction of sleeve ejector system.
There are two parts in sleeve ejector system: center pin and sleeve ejector. Center pin fixes by bottom plate. Sleeve ejector pin fixes by ejector plate. Center pin will create inside dimension of boss. Sleeve ejector pin and core plate will create length and thickness of boss.
II. How sleeve ejector system work.
Center pin fixes in bottom plate, it will create hole of boss and can not move to push product out of the mold. Sleeve ejector pin fixes in ejector plate, it will move to push product out of the mold.
Picture above shown step by step when sleeve ejector moving to eject part, main part is red color, center pin is blue color, sleeve pin is gray color. In this picture, ejector system has two ejector pins and one sleeve pin.
1. After molten plastics injected in to a mold, sleeve ejector pin will create a boss or hole of product immediately.
2.3. After cooling process, ejecting process begin, mold will open. Product will stick in core plate. After mold opening is finished, sleeve pin and ejector pin system will push product out of the mold, product will drop and you get the product.
4. After you get the product, mold closing begin, return pin will touch the cavity and push ejector system return back.