Am 18.04.2013 09:48, schrieb Gregg Eshelman: > How are molds for plastic reflectors machined? They have a large number of > sharp edged corner cubes. > > Could be done with EDM, but how would the EDM electrode be machined? All > those small facets have to be polished for the reflector to reflect light. > > Plastic reflectors have been made like this as far back as 1952. Before that > there were ones with larger corner cube patterns molded in glass. > > ------------------------------------------------------------------------------ > Precog is a next-generation analytics platform capable of advanced > analytics on semi-structured data. The platform includes APIs for building > apps and a phenomenal toolset for data science. Developers can use > our toolset for easy data analysis & visualization. Get a free account! > http://www2.precog.com/precogplatform/slashdotnewsletter > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Gregg, at first, I wondered where the corners in your reflectors are. Of course, I thought at paraboloid shapes, aluminum coated by sputtering and highly reflective. The mold would be easy to make on a lathe. But I suppose, you are speaking of what we call cat's eyes, passive reflectors. These are reflective not for their polish, but because of total reflection on the transition from glass (plastic) to the air. The surfaces don't have to be extremely smooth. They are made by three 60 degree criss-cross milling cuts with a 90 degrees tipped milling tool or on a shaping machine (which yields better surfaces for this purpose).
Peter ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
