In the LMM method of 3D printing, the following process is used for modeling.
First, CAM data is created from 3D CAD data, and the 3D printer is used for modeling. After that, the workpiece is melted except for the hardened part by photo-polymerization, and then a workpiece made of metallic powder and photosensitive resin is obtained. At this stage, the metal powder is still unstable because the density of the metal powder is not high and there is an extra material called resin (this state is also called a green body).
The obtained workpiece is "dewaxed and sintered" in the next process. At this stage, the resin material is melted and volatilized (degreased), and the remaining metal powders are agglomerated and sintered. In the LMM method (and the binder jet method), this sintering process is an important process that determines the quality of the final part, and knowledge and know-how related to sintering are important. Through a carefully controlled dewaxing and sintering process, the density of the final metal part is increased to 98% or more, and the surface is finished to a level that allows mirror-finishing.
In summary, the LMM method uses light to form a green body from a mixture of photosensitive resin and metal powder through photo-polymerization, and after dewaxing and sintering, produces the same metal modeling as the MIM method The advantage of this method is that the material and sintering technologies of μ-MIM® can be deployed directly, which is useful for verification. Since light is used, stacking is extremely stable and part accuracy of ±0.2% or less is possible. In addition, since the workpiece can be removed after molding without applying force, it is possible to mold delicate and complex shapes. As a result, quality comparable to μ-MIM® can be achieved.