Benz Research and Development (Sarasota, FL) is known internationally for providing high-quality, cutting-edge materials for contact lenses and intraocular lenses (IOLs). It holds more than a dozen U.S. patents including the patent on a dimensionally stable soft contact lens material, Benz-G, which remains 100-percent saturated on the eye.
One of the key ingredients to success in manufacturing materials for soft contact lenses is precision. Micron tolerances are needed to produce highly complex geometries with ultrasmooth surfaces. These must be achieved quickly and efficiently to achieve adequate yields.
Ten years ago, realizing it needed to increase productivity, Benz R&D implemented robotics and a comprehensive automation program into its manufacturing process. As part of this effort, Mitsubishi robots from Rixan Associates Inc. (Dayton, OH) were not only integrated into Benz's own manufacturing process, but also into the ILM-2 (integrated lens manufacturing) process. The latter is a smaller version of the company's in-house manufacturing process that Benz markets to other lens producers. It's a complete manufacturing cell that fits into a 10-by-10-foot space.
Today, in its own plant, Benz R&D runs three fully automated production cells for manufacturing IOLs. The first consists of two, four-axis lathes, a mill and a Mitsubishi six-axis robot. The second features a pair of optical blockers (developed and patented by Benz R&D to deliver micron-accurate radius measurement and concentric blocking), and a six-axis Mitsubishi robot. The third includes three, four-axis lathes and a single Mitsubishi six-axis robot.
Prior to adding robotics to its production cells, Benz employed six operators in support. Their responsibilities included feeding parts into the cutting lathes in the three separate production cells. Today, it is the Mitsubishi six-axis robots that feed parts to the lathes and optical blockers. The result has been a dramatic increase in productivity. One operator can now produce over 40,000 lenses per year-four times the industry average.
As part of the process, each blank part is mounted on a bar-coded mandrel. As the robot loads and unloads the parts, data is sent to each machine via the bar code, telling the lathe or milling machine exactly what needs to be done to that specific part. There are no plastic trays or paperwork following the order through the system: only the mandrel with the bar code. Implementing these technologies, the manufacturing process remains the same whether an order is for 300 lenses of the same power or 300 lenses, each with a different power.
Mark Schreiber, manager of automation and mechanical design for Benz R&D, has nothing but good things to say about the system. "We have five Mitsubishi robots in-house and they are extremely robust, consistent and trouble-free," Schreiber says. "Our longest-running Mitsubishi robot has been going strong for 9 years and is still running in Switzerland. Our remaining Mitsubishi robots have been running 5 days a week, 10 to 12 hours a day from 4 to 7 years."
Schreiber adds that the robots provide the company with both flexibility and consistency. Coupled to the proprietary ILM automation program, written in C language, operators can easily and quickly reconfigure the robots to accommodate changes within a production cell. For example, operators can mix up the moves the robots make, so that in addition to going through a normal progression of steps they can also go through those same moves out of order. The robots can also be programmed to respond to the lathes as they signal a lens is in the final stages of cutting.
"We like to call what [the robots] do ‘enhanced pick-and-place' because the robot, using the ILM automation software, can be programmed to be intuitive so it gets ready for its next series of tasks or events," he says.
Benz R&D's ILM-2 manufacturing cell consists of a six-axis Mitsubishi robot, an optical blocker, a DAC ALM-OTT lathe and a DAC four-axis lathe, as well as input and output tracks for handling materials and high-priority orders entering the production cycle. No machine operators are used as part of the ILM process. The automated system produces approximately three times as many finished soft contact lenses per person as the normal process.
"Comments we have heard from custom lens manufacturers who have come to see the ILM in action range from ‘absolutely fascinating' to ‘ultra high-tech,'" says Schreiber. "The use of six-axis robots instead of operators is definitely foreign to these manufacturers. However, spending just one day learning how to easily program and run the robots quickly removes any uncertainty."
For more information on robots and workcells call 937-438-3005 or visit www.rixan.com.
For more information on contact lens workcells call 941-758-8256 or visit www.benzrd.com.