Most 3D printing technologies work in a broadly similar way. They form a precise 2D shape — by extruding, curing, or sintering material, for example — then add successive 2D shapes on top of the original one. The end result is a 3D object, with each layer tightly fused together.
The process of laminated object manufacturing (LOM) is different to most 3D printing processes, though most engineers consider it a form of 3D printing. Uniquely, laminated object manufacturing uses a laser cutter to cut away sections of material in order to give the part its final shape, making it both additive (like 3D printing) and subtractive (like machining). It also resembles traditional printing, because it can use reams of ordinary office paper as feedstock.
LOM is a low-cost rapid prototyping process unlike any other. And although its uses are somewhat limited, it remains an intriguing manufacturing technology for prototyping and modeling.
Laminated object manufacturing is a rapid prototyping process that bonds and cuts sheet material with a computer-controlled laser.
First developed and marketed by California-based Helisys in 1991, LOM emerged as a commercial manufacturing solution the same year Stratasys introduced fused deposition modeling (FDM).  Helisys became Cubic Technologies in the year 2000, but is no longer in business. Mcor Technologies, founded in 2005, was another major LOM hardware company that improved the process by adding full-color capabilities. Its assets were acquired in 2019 by Irish company CleanGreen3D, which continues to develop LOM systems. 
LOM is conceptually very different to a process like FDM. It involves bonding layers of material with an adhesive substance — creating a laminate that is much stronger than its individual layers — and laser cutting precise shapes into each layer.
Though more rudimentary than today’s cutting-edge additive manufacturing processes, LOM offers important benefits like cheap feedstock, colorization, and use in normal working environments such as offices.
Laminated object manufacturing comprises two main steps. The first step is the lamination of sheet material; the second step is the cutting of that material with a computer-controlled laser (or cutting tool).
The lamination process involves layering sheets of material one on top of the next, applying pressure and heat while using an adhesive to bind each layer together. Material is typically fed onto the build platform using rollers, with adhesive applied through a nozzle. After a layer has been rolled onto the build platform, a computer-controlled laser or cutting tool slices a 2D pattern (a cross-section of the 3D part) into it. This process is repeated layer by layer. Once the final layer has been sliced, excess material can be pulled or chiseled away, leaving behind only the precisely shaped 3D part(s).
LOM can create 3D shapes because each 2D pattern sliced onto the material represents a single cross-section of the 3D shape being built. For example, a cone shape can be created by slicing a large circle into the first layer, then slicing circles of ever-decreasing size into each subsequent layer, culminating in a single point on the final layer.
Removal of the excess material can be simplified by “cross-hatching” areas outside of the model. By doing so, small cubes of the excess material can be pulled away, which is easier than removing large sections.
Though principally known as a paper 3D printing technology, laminated object manufacturing can process a few types of material — depending on the particular machine.
Ordinary copy paper is the most popular feedstock for LOM, and the ability to use such a low-cost material is also one of the main advantages of the technology. 
Although paper is not suitable for demanding mechanical applications, it becomes surprisingly rigid when laminated, exhibiting wood-like material properties. Incorporating hard-setting resin or other materials into the adhesive binder can further increase the solidity of the paper parts.
Another advantage of paper is that some LOM machines (such as the CG-1 from CleanGreen3D) can use inkjet technology to color paper at the edges where it will be cut. This enables the low-cost production of full-color 3D models.
Some LOM hardware can process sheet metal in thin gauges. This results in a stronger laminated part, though stronger adhesive and a higher degree of heat may be required, and costs are higher than they are with paper.
A LOM variant called ultrasonic consolidation (UC) or ultrasonic additive manufacturing (UAM) deals exclusively with metals. Popularized by metal AM company Fabrisonic, the UC process creates ultrasonic vibrations to fuse the metal sheets, typically using a CNC mill rather than a laser to cut shapes in each layer. 
Polymer sheets are another possibility for LOM printers. However, use of polymer sheeting instead of paper reduces the environmental friendliness of the technology.
Researchers and companies have successfully used LOM systems to print polymer-based composites reinforced with materials like carbon fibers and ceramics.
Laminated object manufacturing is not a like-for-like replacement for other 3D printing techniques, but it is highly suited to a handful of applications.
In the area of rapid prototyping, LOM represents an affordable route to prototypes of various shapes and sizes. Though not as dimensionally accurate as other additive processes, LOM can be used to fabricate visual prototypes for business proposals, demonstrations, color matching, and other purposes. LOM systems may be appealing for companies that want to carry out in-house prototyping within an office environment.
The ability to colorize paper LOM parts makes the technology suitable for full-color models such as marketing props, toys, and “3D printed selfies.” Color 3D printing, which is useful for both decorative and functional objects, has historically been dominated by processes like PolyJet 3D printing from Stratasys. Some color models may have to be printed on a larger-than-usual scale due to the low level of dimensional accuracy offered by LOM.
Paper LOM 3D printing is an excellent means of making architectural models, which have traditionally often been made by hand from balsa wood. Laminated paper offers similar material characteristics to wood, but digital fabrication using LOM is much faster and more accurate than manual model making.
Manufacturers carrying out sand casting or investment casting can use LOM to make sacrificial patterns.  An engineer can design a 3D object using CAD software, print it in paper using LOM hardware, then build a sand mold around it. The paper pattern can then be burnt out, creating a cavity within the mold, and the casting material can be poured in.
Laminated object manufacturing offers some highly desirable benefits, including affordability, a large printing envelope, and usability in offices. It also has its drawbacks, such as low accuracy and certain geometrical limitations.
|Paper feedstock more affordable than typical 3D printing materials||Less dimensionally accurate than most 3D printing processes|
|Machines can be operated in non-industrial environments||Complex internal geometries difficult or impossible to achieve, since material must be manually removed|
|Potential for colorization||Few companies developing hardware; possibility of obsolescence|
|Can fabricate large objects with open build area||Hardware more expensive than FDM|
|Can fabricate overhangs, since preceding layers of material act as a support||Paper parts can absorb unwanted moisture unless carefully treated with sealant|
|Can create composite laminates by alternately layering one material then another||Few users worldwide, making it difficult to find online tips and solutions from other users|
Laminated object manufacturing occupies its own space in the 3D printing landscape. The process provides advantages that are difficult to find elsewhere, and its ability to print 3D objects from paper makes it one of the most environmentally friendly 3D printing options.
Companies that need a low-cost, low-maintenance rapid prototyping solution might find LOM to be a perfect fit. The process is certainly hard to beat when it comes to making quick visual models. On the other hand, companies investing in their first 3D printer might consider LOM a riskier proposition than a process like FDM, since the overall number of hardware developers and users is low.
Looking forward, paper 3D printing may well remain a niche concern, but LOM-adjacent additive manufacturing technologies like ultrasonic consolidation could become powerful tools in the modern factory.
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