The paper ‘Understanding the behaviour of pulsed laser dry and wet micromachining processes by multi-phase smoothed particle hydrodynamics (SPH) modeling’ by Muhammad et al published in 2013 J. Phys. D: Appl. Phys. 46 095101, laid the foundation for SPH simulation of laser melting process including welding and selective laser melting. However, there are some inaccurate or inappropriate mathematical descriptions about the energy conservation in the paper, which may mislead some careless readers and cause unnecessary waste of time. In this paper, some comments and clarifications on the errors are made. By correcting these errors, a deeper understanding on the energy transport during the laser melting processes can also be obtained.

Muhammad等人在2013年的《物理学报》上发表了论文“通过多相平滑粒子流体动力学（SPH）建模了解脉冲激光干，湿微加工过程的行为” 。D：应用 物理学。46 095101，为SPH模拟激光熔化过程（包括焊接和选择性激光熔化）奠定了基础。但是，本文中关于节能的数学描述不准确或不恰当，可能会误导一些粗心的读者并造成不必要的时间浪费。本文对错误进行了一些评论和澄清。通过纠正这些错误，还可以更深入地了解激光熔化过程中的能量传输。