Damping support fixture for vibration suppression in milling of thin-walled casing
Machining vibration is one of the main phenomenon occurs in milling of thin-walled workpiece, it will lead to poor surface finish and low machining efficiency. Especially for challenging situations such as large dimension closed casing, vibration is one of the main factors affecting the improvement of machining efficiency. In this work, a method by applying damping support fixtures for machining vibration suppression is developed. It can be mounted at different positions on the inner surface of casing to suppress vibration. This method has been validated by finite element simulation and cutting experiments. The results show that vibration can be suppressed with the presence of damping support fixtures. The new method can be used to get higher machining efficiency and better surface finish in milling of thin-walled casing.
Material removal process optimization for milling of flexible workpiece considering machining stability
The material removal process of a flexible workpiece has a great effect on the stability limits and chatter-free machining time, as the sequence of material removal can be altered to obtain a better workpiece dynamic behaviour. Therefore, the uncut material can be better designed to get chatter-free machining conditions and a shorter machining time. With this as the objective, a material removal process optimization method is presented to design the uncut material distribution. Different from existing methods, the presented approach begins from the last machining step, the maximum stable cutting depth is calculated, and the removed material is virtually added to the design model. Therefore, beginning from the design part, the material is virtually added to the part and the stock model of the part is finally obtained. Based on this approach, the optimized uncut material can provide support for the part in the semi-finish or finish machining processes, and the machining process is stable. Optimization results show that while machining plate-like structures, step removal methods can be used and the arc or triangle shape machining allowance can be used to get better machining results. Cutting experiments were carried out to show the effectiveness of the presented approaches.
Composite monolayer fabrication by an arc-spray process
A single layer (monotape) technique for fabricating complex high-temperature tungsten-fiber-reinforced superalloy composites is proposed. The fabrication of sheets of arc-sprayed monotape 38 cm wide and 122 cm long has been demonstrated. Composites fabricated using the method are shown to have equal tensile strength and a cleaner matrix than composites fabricated from powder metal cloth monotapes, and the present technique is less expensive than the powder metal fabrication techniques.