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 CO2 laser, each sheet representing one cross-sectional layer of
- PDF / 873,648 Bytes
- 30 Pages / 439.37 x 666.142 pts Page_size
- 70 Downloads / 282 Views
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 CO2 laser, each sheet representing one crosssectional 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.
8.1
Gluing or Adhesive Bonding
The most popular lamination build material has been paper with a thermoplastic coating on one side. This type of adhesive-backed paper is similar to the “butcher paper” used to wrap meat. Paper thicknesses often range from 0.07 to 0.2 mm. Potentially any sheet material that can be precisely cut using a laser or mechanical cutter and that can be bonded can be utilized for part construction. A further classification is possible within these processes. In one category, there are processes in which the laminate is bonded first to the substrate and is then formed into the cross-sectional shape (“bond-then-form” processes). In another category, there are processes in which the laminate is formed first and then bonded to the substrate (“form-then-bond” processes). I. Gibson, D.W. Rosen, and B. Stucker, Additive Manufacturing Technologies, DOI 10.1007/978-1-4419-1120-9_8, # Springer ScienceþBusiness Media, LLC 2010
207
208
8 Sheet Lamination Processes Optics X-Y plotter Layer outline and cross-hatch
Laser Heated Roller Polymer-Coated Paper
Excess Material Part Block Build Platform
Material Supply Roll
Fig. 8.1 Schematic of the LOM process (based on [1] JOURNAL OF MATERIALS PROCESSING TECHNOLOGY by D.I. Wimpenny, B. Bryden, I.R. Pashby. Copyright 2003 by Elsevier Science & Technology Journals. Reproduced with permission of Elsevier Science & Technology Journals in the format Textbook via Copyright Clearance Center.)
8.1.1
Bond-then-Form Processes
In “bond-then-form” processes, the building process typically consists of three steps in the following sequence: placing the laminate, bonding it to the substrate, and cutting it according to the slice contour. The original LOM machines used this process with adhesive-backed rolls of material, where a heated roller melted the plastic coating, c
Data Loading...
