The word “lens” is derived from the Latin word for “lentil,” a common type of bean. Lenses are used in various optical devices, including glasses, contact lenses, microscopes, and telescopes. A lens is a curved glass or transparent material that bends light to create an image. 

There are many different ways to fabricate a lens, but silicone molding is one of the most innovative methods. In this process, a mold is created from a negative image of the desired lens. The mold is then filled with liquid silicone and cured to create a solid lens.

This method has many advantages over traditional lens-making methods, including increased accuracy and decreased costs. And because the mold can be reused, it is also a more sustainable way to fabricate lenses.

If you’re interested in learning more about how lenses are made, read on!

Steps in Creating Lenses through Silicone Molding

Step 1. Cleaning the Mold

The initial step in casting any resin, particularly a lens, should be cleaning the mold. Making a lens is even more crucial because every flaw, such as dust or dirt, will be magnified. Having said that, the lens must be perfect.

Step 2. Mixing the resin material

Make sure the resin is correctly blended from both of its portions. This entails ensuring the right quantity of each resin component is used. (In general, it is split into two parts: Part A and Part B.)

Step 3. Loading the mixture into the vacuum chamber

The following stage is quite easy; combine Parts A and B in a vacuum chamber to eliminate as many bubbles as possible. The resin type will determine how long you maintain it in the vacuum chamber. There was no urgency to remove the resin from the vacuum chamber because the resin we chose takes around 20 minutes to begin curing.

Step 4. Pouring the mixture

Pour the resin into the mold slowly to prevent adding any bubbles after the mixture has been removed from the chamber.

Step 5. Using the pressure chamber

Place the mold into a pressure chamber after the resin has been placed in it, then wait for the necessary amount for the resin to cure.

Step 6. Removing the lens from the mold

The final step is self-explanatory: remove the lens from the mold and check that it is in perfect condition. If something goes wrong, go back to Step 1 and retry.

Challenges and Solutions in Molding Lenses

The biggest challenge with most resin casting projects is preventing bubbles. As was previously said, faulty lenses will amplify even the smallest flaws and distort any projected image that passes through them.

Parts may distort or not form when casting resin, which is another potential issue.

It will take creative thinking to find a solution to the bubble problem. First, you must inject resin from the bottom of the mold because doing so results in bubbles.

Following that, these are the procedures to inject the epoxy from the mold’s bottom:

• Make a hole in the mold’s bottom, making sure the hole is large enough to accommodate a rubber tube’s end.
• The resin will then be injected into the mold using a syringe.
• To add more resin to the mold, place a straw on the area where the resin will be injected. In this manner, when and if the bubbles appear while the mold is in the sealed chamber. It will pull the resin and refill the space. 

Although it is not the simplest approach, casting lenses by silicone molding is a reasonably cheap option to prototype lenses before purchasing previously formed blanks from a reliable supplier or manufacturer.

Conclusion

It’s time to use your flawlessly cast lens, providing everything went according to plan during the process. You can use the steps mentioned above as a guide or utilize your creativity to develop something wholly original.

It’s okay if your lens isn’t flawless. Getting anything correctly requires a few tries. That is another aspect of silicone molds’ beauty. Using the same mold, you can recast it till it is perfect. The adage “practice makes perfect” is accurate.

Nice Rapid can help you with any step of the optical fabrication process, including design, prototype, and production.