1. Historically importantIt wasn’t very long after the invention of photography that people began to think about extending the process to three dimensions. The impetus of a lot of the early work was to produce items such as relief maps and portrait busts. By 1956, Otto Munz had described a system with impressive similarities to stereolithography which was still 30 years in the future. Much like stereolithography, Munz’s method uses sequentially exposed layers of hardenable photographic emulsion contained in a vat with an elevator platform. Layers are exposed through photographic negatives. Aside from the use of a computer to create the film images and more advanced chemistry, the architecture is very similar to many of today’s photopolymer-based technologies.
Many of the early inventors both described means of gathering data - what we would today call reverse engineering - as well as the creation of the replica or object. In the 1970’s, a series of patents to Paul DiMatteo and others, and assigned to Dynell Electronics covered this range of technology, as well. The thrust of the business was to build a service for producing life-like portrait busts. Multi-camera photographic methods were used to generate the data for CNC machining-based rapid prototyping. The company garnered some national media coverage, but not much seems to have come of it business-wise.
Numerous patents were also issued in the 1970’s to inventor Wyn Swainson and others, and assigned to the Formigraphic Engine Corp., describing an early effort to utilize photopolymer materials. The technology was under development by the Battelle Memorial Institute for a number of years before finally being abandoned. Battelle was trying to replicate in three dimensions the success they had had in two dimensions by taking a technology upstart, namely Haloid Corporation, and turning it into Xerox. Regrettably, they were not to experience the same good fortune with Formigraphic.
While the technology used scanned lasers and photopolymers, much like stereolithography, the process was more complex. The object was formed within a vat of photopolymer at the intersection of two individual lasers scanned from right angles through windows in the vat walls. Each of these lasers were of different colors and the photopolymer was designed to solidify only where they intersected in the x-y plane. Aside from the obvious complexity of materials design, the method suffered from the appreciable attenuation and optical distortion experienced by the laser beams as they traveled variable distances though the photopolymer. Contrast this situation with stereolithography, which advantageously keeps a well-controlled beam on the surface of the vat.
Formigraphic’s technology lives on, however, in methods of making micro- and nanoscale parts that use two photon absorption. The small size of these parts avoids the laser problems experienced at macro scales.
Ross Housholder’s patent was another prescient publication that anticipated much of what was to come. Although nominally it bears the closest resemblance to selective laser sintering, it also describes aspects of fused deposition modeling and stereolithography. The assignee was HiCo Western Products, a company that still exists and in which the Housholder family remains involved. HiCo now provides ingredients for barbecue cooking. Perhaps it always did - someone should look into this - but in 1981 Mr. Housholder was one of the first people thinking about applications ranging from toolless ceramic molding to the creation of 3D hard-copy models for medical CT scans and the like.
Use the Prev | Next links provided on each page to proceed sequentially through the entire patent list, although not precisely in the order the entries appear in the table. Links provided in the "Technology Area" column will take you to pages within the WWGRP site that either briefly explain the method, or to directory listings or archived materials where more information can be found.