Simultaneous dynamic processing strategies of hybrid wire arc additive-milling subtractive manufacturing based on stability region simulation and stiffeners assistance

Hybrid wire arc additive-milling subtractive manufacturing (HWMM) provides an approach for producing complex, low-volume structural components. However, milling of the dynamically evolving structure during HWMM is prone to chatter, resulting in process instability. To address this problem, a finite element modal analysis model was developed to evaluate the dynamic characteristics of the milling system. Based on the dynamic model of the “rigid tool–flexible workpiece” system, a stability lobe diagram was established to identify the optimal process window. As the deposition height increases, the natural frequency decreases, causing the stability lobe diagram shifts toward the lower-left region and the process window to shrink. Experimental validation using randomly selected parameters within the stable region showed good agreement with predictions. The mean of milling vibration and Ra values of the chatter-affected sample were 10.5 and 4.1 times higher, respectively, than those of the stable milling sample. To alleviate the reduction of the process window, the influence of stiffeners on natural frequency was investigated. T-shaped and J-shaped stiffeners produced the most significant increase in natural frequency, providing an effective way to expand the process window. A milling scheme for HWMM is proposed to enable rapid parameter determination and improve machining accuracy and efficiency.