PET composite material is a new type of structural composite plate product made of metal sheet as the panel, PET invoice material as the core material, which is continuously compounded online at high temperature.Because the thermal melting point of materials in the composite layer is not consistent, the processing method of thermal cutting is obviously not suitable,the traditional processing method is usually mechanical cutting, that is, grinding wheel or saw blade cutting.This approach is prone to two drawbacks:One is incision injury, that is, the incision near the edge of the incision is stratified, torn, burr, wire drawing and other phenomena;The other is the lamination between layers, that is, the separation between layers of composite material, so that the internal structure of the component loose, reduce the strength of the component.Ultra-high pressure water cutting due to the non-contact cold processing technology, no stratification phenomenon in the processing, the material will not appear coking and hot crack.Ultra-high pressure water cutting speed, and sand cutting in the fine sand and grinding effect, so that the cutting surface smooth, smooth, accurate.