Waterjet vs. CNC router

Which machining process is best suited for polyethylene, cutting with a waterjet or cutting with a cnc router. In order to answer this question all factors of production related to the project must be addressed.

Factors include; feed rate, setup time, tool diameter, cut quality and overall versatility in 3 dimensional space.

Feed Rate: Waterjets can cut multiple layers at one time. In this project showcase the waterjet was capable of cutting 4 sheets, 3/16" thick at a feed rate of 30 in/min. Relate the same to a CNC router. Typically a router setup will only allow one sheet at a time. One sheet @ 3/16 can be routed at a feed rate of 70 in/min. Quicker than the waterjet right? Not so. remember the waterjet was cutting four sheets @ 30 in/min. You must multiply 4 sheet times 30 in/min to calculate the individual sheet feed rate. In this case it turns out the waterjet can cut one sheet at a combined rate of 120 in/min. That is almost 75% faster than the router.

Setup Time: As stated above, the water jet is capable of cutting 4 sheets at a time equaling 1/4 the amount of time required to set the same project on a CNC router.

Tool Diameter: Typical CNC routers run a 1/2" diameter bit for cutting plastic. This will produce a 1/4" radius on all inside corners. The water jet cutting stream is approximately .08" diameter creating a .04" radius on inside corners.

Cut quality and versatility typically goes to the CNC routers. Router can produce intricate 3D designs as well as completely finished cut surfaces. Waterjets thrive on fast, large run projects. The majority of parts cut with a waterjet will experience further fabrication after being cut to size.

To find out if waterjet cutting is right for your project please go to Cobaltdm.com