Laminated object manufacturing is a lesser known additive manufacturing process where an object is created by successively layering sheets of build material, bonding them through heat and pressure and then cutting them into the desired shape using either a blade or a carbon laser. Mcor Technologies offers a newer form of the process known as Selective Deposition Lamination. In this process, sheets of standard A4 or letter-sized paper are cut into shape using a tungsten carbide blade and then bonded by selectively placed droplets of a water-based adhesive. Areas that will make up the final part receive a high concentration of the adhesive, while areas used for support receive less.
Originally developed by Helisys (now Cubic Technologies), the LOM process uses a system where a continuous sheet of build material is drawn across the build platform by a system of feed rollers. For paper and plastic build material, the sheet may be coated in an adhesive. A heated roller then passes over the material, melting the adhesive and pressing the material down onto the platform. A blade or laser then cuts the desired pattern into the material and crosshatches the unused material so it can be removed later. A take-up roll winds up the remaining material. Finally, the build platform drops down the thickness of one layer, new material is pulled across the platform and the process is repeated.
The rigidity of the build material means that no support material is needed during the build process. Interior voids within the object are heavily crosshatched during the cutting process, thus allowing the material to be removed easily. The nature of the process means no enclosed chamber is needed, though some environmental conditions must be maintained for the layers to properly fuse.
Some advantages of the LOM process are that the materials being used are consistent, readily available and well understood. Depending on the type of binding resin used, LOM provides one of the largest operating temperature windows.
On the downside, this process has more limited 3D geometries than other AM processes. The solidity of the object is also highly dependent on the resins and curing process used. The resins are limited to those objects made using paper or plastic. Metal sheets are welded (either thermal brazing or ultrasonic welding) or bolted together to form the part. The use of metal in the LOM process is rare.
Cubic Technologies is another company that uses the LOM process. It works with paper, plastic and metal. In its process, objects made using paper take on a wood-like texture and can be shaped in a similar way.
