In order to achieve flexible and autonomous milling operation, a system called Digital Copy Milling (DCM) was developed in our previous studies. Additionally, tool motion control, in which Voxel information of removal volume Voxel model is referred, is performed on the DCM. In this study, a feed speed control function and a tool posture control function are integrated to the DCM by referring feed speed and tool posture parameters stored in Voxel properties of removal volume Voxel model. It is assumed that these parameters change gradually as a diffusion phenomenon to determine Voxel properties automatically using diffusion equation. In order to calculate diffusion equation, Voxel in removal area corresponds to a calculation grid of diffusion equation not just as storage of feed speed and tool posture parameters. In the experimental verification, feed speed and tool posture parameters were determined automatically, and the tool motion was controlled independently of tool path generation successfully to perform milling operation.