Eyeglass Lens Molding Line
A flexible high-speed automation processing line had to be designed and built for the production of prescription optical eyeglass lens blanks. The solution had to produce lens blanks every 10 seconds, with a process time of less than one day, and the flexibility to handle up to 45,000 unique prescriptions.
The present manual process yielded a high variation in product quality, as well as a process time of almost two weeks per lens.
The team designed and constructed a class 1000 cleanroom system that consisted of eight different process stations used in conjunction with a rotary Automated Storage & Retrieval System (ASRS). The goal was to provide a system where a lens could be manufactured per a customer’s specific prescription. To accomplish this, two glass molds for the front and base curves of each lens were stored in four rotary ASRS units. The ASRS design allowed for 4,500 molds to be stored in the system, which could be randomly combined to produce over 45,000 different lens prescriptions. The glass molds were retrieved based on specific parameters input from an Internet interface and downloaded into a lens recipe. Upon receipt of the recipe the glass molds were placed on a pallet, then pressed into a mold ring where they were held in place. The glass molds were presented to a process station where a liquid monomer was introduced into the mold gap then subsequently cured into polymer using UV light.
outcomes and benefits
The team produced an automated e-commerce enabled ASRS system for “lot size 1” production of prescription recipes. What used to take two weeks now takes less than 1 day, but is flexible enough for 45,000 different prescriptions. Additionally, by eliminating operator intervention, lens quality has shown significant improvement. The system can produce a finished lens blank every 10 seconds, and the start to finish process time has been reduced from two weeks to less than 30 minutes.
New Solution Leads to Large Decrease in Process Time