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Profiles of object cross sections are cut from paper using a CO2 laser as shown in Fig. 3. The paper is unwound from a feed roll (A) onto the stack and bonded to the previous layer using a heated roller (B). The roller melts a plastic coating on the bottom side of the paper to create the bond. The profiles are traced by an optics system that is mounted to an X-Y stage (C). The process generates considerable smoke. Either a chimney or a charcoal filtration system is required (E) and the build chamber must be sealed.
 After cutting the geometric features of a layer is completed, the excess paper is cut away to separate the layer from the web. The extra paper of the web is wound on a take-up roll (D). The method is self-supporting for overhangs and undercuts. Areas of cross sections which are to be removed in the final object are heavily cross-hatched with the laser to facilitate removal. It can be time consuming to remove extra material for some geometries. In general, the finish, accuracy and stability of paper objects are not as good as for materials used with other RP methods. However, material costs are very low, and objects have the look and feel of wood and can be worked and finished in the same manner. This has fostered applications such as patterns for sand castings. While there are limitations on materials, work has been done with plastics, composites, ceramics and metals. Some of these materials are available on a limited commercial basis. Variations on this method have been developed by many companies and research groups. For example, Kira's Paper Lamination Technology (PLT) uses a knife to cut each layer instead of a laser and applies adhesive to bond layers using the xerographic process. Solido 3D Ltd. also uses a knife, but instead bonds layers of plastic film with a solvent. There are also variations which seek to increase speed and/or material versatility by cutting the edges of thick layers diagonally to avoid stair stepping. While the technology has been successful in certain applications, it hasn't fared well as a general solution. Several producers have come and gone. The principal US commercial provider of laser-based LOM systems, Helisys, ceased operation in 2000. However the company's products are still sold and serviced by a successor organization, Cubic Technologies. Solido 3D closed its doors in January, 2011, and Kira has had limited sales success. Mcor Technologies is the most recent entrant. It emphasizes the low cost of materials in its marketing.
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