What is a Waterjet?
A waterjet is a CNC machine that uses 40,000 PSI and above of pressurized water, along with an abrasive, to cut just about any material to any shape desired. Whether it’s typical materials, such as steel, copper, aluminum, or exotic materials, such as glass, marble, and granite all of these can be cut effectively using a waterjet.
What are the advantages of Waterjet Machining?
Waterjet machining is significantly more versatile than other methods of cutting in that it can handle just about any type of material, at thicknesses beyond half an inch, and also leaves a cleaner edge finish than any of the other cutting methods. Finally, the precision can be down to thousandths of an inch.
Some of the other methods used for machining various materials include plasma and laser. Both of these can be extremely effective at cutting, however, both create problems with “heat affected zones”. There is ultimately an extreme amount of heat generated at the cutting point on the material, causing scorching, and especially in the case of plasma, very rough edges. Laser quickly encounters limitations past a certain thickness of material, and often has trouble with reflective surfaces.
Who uses Waterjet Machining?
Just about everyone who needs something cut precisely and quickly! From artists to people working on complex industrial systems, the range is pretty wide.
Perhaps one of the most surprising applications, however, might be in the food industry. In contrast to the services we provide, this type of work is done without abrasive (pure water), and is done by machines that are specifically USDA approved… We have been known to carve the occasional Pumpkin, however.
What does the process look like?
The process begins with a drawing. Typically, a .DXF file, which is an Open CAD format, is submitted in addition to the thickness and type of material, along with any other requirements of the project. Once this information is known, an estimate can be provided. The drawing is first processed to make sure no extraneous lines are present, no gaps along the paths of a parts, etc. The drawing is then converted to a “Machine Path” using Omax Layout. This is where the details of how a part is cut are defined, and determines all of the following:
- The edge quality is defined. This determines how smooth the finish of the resulting cut will be.
- The order parts are cut out in. (For example, you would probably want any inside cuts to happen before the entire part is cut out.
- The toolpath is created. While the “Kerf” or “width of the Waterjet stream” is relatively thin (just as is the thickness of a saw blade), it cannot be ignored. To be precise, it is 0.030″ on our machine. This means that it is important to know whether it is the inside, or outside dimensions of a part that need to be cut.
- “Lead-ins” and “Lead-outs” are defined. You can think of a lead-in as a “pilot hole”. This happens on a part of the material that is outside of the dimensions of the final product.
- If multiple quantities of a particular part are to be created, this is also the stage at which the parts would be “nested”. This is where the parts are placed as close to each-other on the material as possible, to minimize waste.
Here are some videos, courtesy of Georgia Tech’s Invention Studio, that demonstrate what is involved in the process: