In compression moulding, plastic material that is melted is extruded, cut and inserted into a cavity. It is then moulded into its shape under hydraulic pressure. Compression moulding is popular as it is a low tool maintenance option that makes it easier to run higher volumes with less downtime.
Unlike injection moulding, there is no gate present. So gate vestige is avoided and visual appearance is better. Compression also offers the ability to be more efficient with colour changeovers. Compression moulding is more limited when needing complex geometrics and larger diameter closures that are greater than 48mm.