*6.2.5.1 Proposed solution*

The previously printed layer should be cooled completely before printing the new layer. That could be performed by installing a cooling unit with the help of in-situ method. The cooling unit will work simultaneously while recording temperature of in-situ method. Similarly, variant building direction will accumulate heat in different direction and reduce the average heat. Heat treatment can be a traditional solution if the workpiece could not be collapsed during the printing process. According to the author's understanding, another way to solve the issue of heat accumulation or residual stress is by using nucleation after printing. Nucleation is a process of formation of a new crystalline structure during solidification. This process might be applied on the printed parts by heating it to a temperature lower than the melting point and building new crystalline structure with the desired mechanical properties, grain size, free residual stress and heat accumulation.
