Sheet Lamination Processes

One of the first commercialized (1991) additive manufacturing techniques was Laminated Object Manufacturing (LOM). LOM involved layer-by-layer lamination of paper material sheets, cut using a CO

2

laser, each sheet representing one cross-sectional layer of the CAD model of the part. In LOM, the portion of the paper sheet which is not contained within the final part is sliced into cubes of material using a cross-hatch cutting operation. A schematic of the LOM process can be seen in Fig. 8.1.

A number of other processes have been developed based on sheet lamination involving other build materials and cutting strategies. Because of the construction principle, only the outer contours of the parts are cut, and the sheets can be either cut and then stacked or stacked and then cut. These processes can be further categorized based on the mechanism employed to achieve bonding between layers: (a) gluing or adhesive bonding, (b) thermal bonding processes, (c) clamping, and (d) ultrasonic welding. As the use of ultrasonic welding is relatively new, and is an area of considerable research interest, an extended discussion of this bonding approach is included at the end of this chapter.