How Laminated Object Manufacturing (LOM) Works
The term "3D printing" refers to building up an object additively. This is accomplished using a number of different methods. Laminated Object Manufacturing is one type of 3D printing process.
Laminated Object Manufacturing works by layering sheets of material on top of one-another, binding them together using glue. The printer then slices an outline of the object into that cross section to be removed from the surrounding excess material later. Repeating this process builds up the object one layer at a time. Objects printed using LOM are accurate, strong, durable and generally show no distortion over time which makes them suitable for all stages of the design cycle. They can even be additionally modified by machining or drilling after printing. Typical layer resolution for this process is defined by the material feedstock and usually ranges in thickness from one to a few sheets of copy paper. Mcor’s version of the technology makes LOM one of the few 3D printing processes that can produce prints in full color.
The most common materials used in LOM are metals, plastics and off-the-shelf copy paper. Paper models have wood-like characteristics and can be worked and finished accordingly. When using paper as a stock material, the sheets can first be printed using a traditional printer to color the edges of the model, where the paper will be sliced for later removal. This allows the finished object to have accurate and well saturated color. When using other materials as feedstock, they can be mixed and matched for various layers throughout the printing process giving more flexibility in determining the physical properties of the finished object.
How it works
Sheets of material are positioned on top of one another after first applying an adhesive glue to bind the newly applied layer to the existing structure. The adhesive glue can be selectively applied, meaning that a higher amount is applied in the area that will become part of the object, and a lower amount is applied in the surrounding, supportive area. This uses the glue as efficiently as possible, since the scrap area does not need as strong a bond. After the new sheet is precisely layered on top of the existing model, bonded together with the adhesive, heat and pressure are applied, usually using a compressive plate. This ensures a tight fit between layers.
After bonding, a knife or laser cuts the newly bonded sheet of material, tracing a 2D outline of the model’s cross section before the next layer of adhesive glue is applied and the next sheet added. The accuracy of LOM is slightly less than Stereolithography (SLA) and Selective Laser Sintering (SLS). There is no chemical reaction required, however, which means that relatively large parts can be produced reliably. LOM is also considered a comparatively inexpensive 3D printing method to operate, due to the widely available and low cost materials involved.
The only post processing step for LOM is the peeling and removal of excess material. However, this can often be tricky. The ease of removal depends on the design of the printed part; sometimes shaking the part is enough, whilst other times support structures must be chiseled out manually. The waste, or support, material is often diced by the printer to aid in its removal without damaging the 3D model.