How to cut aluminum? By China CNC Router or waterjet? Sheet size would be 4' x 10' with a thickness of 1/4-1/2". Such aluminium is for fabricator, many companies use plastic and wood laminates. it would be a better investment for the company to buy a machine that could do multiple things as opposed to a water jet or china cnc router which will only cut steel and aluminum.
You can cut aluminum with a china cnc router. The China cnc router needs to be set up with lubricant spray and the vacuum pump cannot be one with graphite vanes - if the lubricant sucks through the vacuum to the pump and gets on the vanes, they are toast. Routers are not really made for cutting metals, however, the key word above is "can." For working metal, it is better to get a mill, as they are engineered for metal work in terms of feed rates, rotation speeds, adequate lubricant flow, recycling lubricant, etc. Hold downs are usually mechanical using t-channel (rather than vacuum, as is typical on China CNC routers). Routers' rotation/hp ratio are typically best at higher rotational speeds (like 18,000 to 21,000 RPM), which are way higher than those normally used for metals. I have been doing aluminum on our China CNC router.