Topic: It can be a little tricky to de-mold certain lenses, especially plus lenses with thinner edges and lenses that have overfilled with monomer.
The Reason Why: The lens material is still attached to the molds in certain areas making it tough to release from the molds.
The Fix: By utilizing the proper de-molding techniques your lenses will release intact and remove more consistently from the molds:
As soon as the alarm sounds for the completion of the mold cavities in the Post Cure Unit, remove the mold cavity from the Post Cure Unit. Remove the gasket and throw it away. Place the mold cavity in the de-molding tub for 10 seconds.
Remove the mold cavity from the de-molding tub take the blue handled scoring tool first, utilizing a scraping motion to remove the two notches of monomer that are on both sides of the fill port that make up the air holes. Also scrape any residue that is on the edges of both front and back molds.
Then score around the periphery of the lens both front and back using the sharp point located on the blade of the blue handled tool. *Note: It is very important that the sharp point on the blade of the scoring tool be sharp. If it becomes dull then a replacement blade should be attached.
Using the black handled de-molding tool locate the de-molding notch on the mold cavity and place the tip of the de-molding tool inside the notch. This notch is found directly opposite of the fill port on the mold cavity. Place the tip of the de-molding tool in the notch and separate the molds using a prying motion (up and down). It also helps if you slightly push on the de-molding tool as you are making the prying motion.
Once the mold has separated from the lens then place the lens and mold that are still attached back in the de-molding tub. In a matter of seconds the mold should begin to release from the lens. You can assist the release by again scoring around the periphery of the lens and mold. Your lens should release from the mold quickly and intact.
Posted on 02/06/2014 at 12:00 AM
