NALUX NANO OPTICAL, INC.
65 E.State Street, Suit2000
Columbus, Ohio 43215
c/o Schneider Downs
"Lighting a path to the future with nano-optics."
Injection molded plastic optics are some of the most demanding plastic products molded today and Nalux is one of the largest suppliers of injection molded plastic optics in the world. Other plastic products (pen caps, te buttons on your computer keyboard, etc.) are fairly easy to mold injection molded plastic optics can be a nightmare. If a small speck of dust gets into an average plastic part, then it is usually colored anyway so nobody sees it. If a bottle cap is slightly warped, well the plastic used to make bottle caps is relatively soft anyway so it isn't difficult to still be able to fit the cap onto the bottle. An additional molding problem is flow lines, which is the liquified plastic not flowing smoothly in the mold and creating a noticable line in the molded part. For a colored part, this is usually irrelevant. For injection molded plastic optics, this flow line can cause the beam of light that passes through the optic to be diverted from it's intended path.
Injection molded plastic optics are much more difficult and demand far greater skill and superior equipment than your average plastic part. If a speck of dust gets into injection molded plastic optics, then the speck will obstruct the light and the optic won't be any good. If the injection molded plastic optics are slightly deformed, then it is like an eyeglass lens with the wrong prescription for your eyes and the focus of the lens won't be correct. The effect of flow lines on injection molded plastic optics has already been mentioned. Injection molded plastic optics have to be just about perfect. Not once, but millions of times. For example, Nalux makes many millions of injection molded plastic optics called pick up head lenses (the small lenses in DVD and CD players) every year. These injection molded plastic optics have to be just right so that the laser beam that goes through the lens is not blocked by any specks, it's not diverted by a flow line, and it's shape is correct so that it focuses the beam to the correct distance.
Injection molded plastic optics are usually made using electric molding machines because these machines usually exhibit better process control than the traditional hydraulic machines. The molds for injection molded plastic optics have to be highly polished because an unintended rough surface to an optic will cause the light that passes through the optic to be scattered to places you don't want it to go. Very often the molds for injection molded plastic optics have pressure and temperature sensors built into the molds so that the injection process can be controlled very precisely preventing unnecessary stresses from being molded into the part. Advanced mold materials such as Copper/Beryllium alloys are often used because they transfer heat very quickly and some injection molded plastic optics (such as f-theta lenses used in office printers) are very thick (upwards of .75" thick) and the heat needs to be removed quickly so that the part cools and hardens before it can warp into an unwanted shape.
The plastic used in the molding of injection molded plastic optics must also be very pure. As mentioned before, a speck of dust which is insignificant when molding a bottle cap can be the kiss of death for injection molded plastic optics. Not only contaminants are an issue. When the raw plastic pellets used in the molding machines are created from oil, the basic plastic building blocks are first created as monomers and then the monomers are bonded together in long molecular chains called polymers which can be molded into injection molded plastic optics. Unfortunately, during this process, not all of the monomer gets "polymerized" so there are tiny gels of unpolymerized monomer trapped in the pellets. The monomer doesn't flow the same way as the polymer nor does it have the same optical properties so injection molded plastic optics can end up with these gels in them and the gels act just like specks of dust and interfere with the light passing through the lens.
Quality control for injection molded plastic optics can also be a very involved process. Advanced vision machine systems are used in line to check for contaminants and other defects. A small percentage of the injection molded plastic optics are inspected on specially rigged and monitored devices that they will be used in when assembled into their final product. The performance of the lightwaves after they pass through the injection molded plastic optics are then measured to make sure the optics will perform well in the field. And finally, although science has tried to match it, there is just no substitute for a high power microscope and the human eye to check for defects in injection molded plastic optics. Once trained for small details, it is amazing how efficiently the human eye can pick up flow lines, specks, and other quality problems.
Injection molded plastic optics are a class of plastic part that forces the molder to come as close to perfection as possible. Fortunately Nalux has forty years of experience with injection molded plastic optics so that the world can watch its movies and listen to its music for years to come.
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