A part machined from 0.4″ (1 cm) steel
This picture shows how with some modern abrasivejets you can get sharp inside corners at quite high precision. There is a mating part that slides nicely right into it, and it is really impressive how close the fit is.
A selection of gears machined from ½” (1.3 cm) aluminum
This is what you get when you raise the nozzle about one foot (30 cm) above the table, then fire into the catcher tank
The catcher tank is typically full of water and abrasive. The overflow water is either discarded to a drain line, or can be cooled and recycled. The spent abrasive accumulates in the tank, until it reaches a point where it needs to be cleaned out, usually using a shovel and some strong backs. There are systems available that will automatically remove the abrasive.
Close up of a nozzle in action
Most of the time, the end of the nozzle and the material is submerged while they are cutting. Cutting in air is extremely noisy (and requires hearing protection), while cutting in water is much quieter. Cutting under water has little or no effect on the cutting process, although some materials (cardboard, wood) can’t be cut under water because of the effect water has on the material.
Waterjet machining systems make it easy to raise and lower the water level. The water level is lowered for loading, positioning and fixturing the material and is then raised for machining. The level can also be lowered during machining to monitor progress or remove finished parts.
A “mini-jet” nozzle cutting
A mini-jet is a smaller version of a regular nozzle with a smaller water stream–a mini-jet nozzle has a cut width, or kerf, of approximately 0.020″ (0.5 mm) compared to a regular kerf of about 0.060″ (1.5 mm). While this reduces the cutting power of the mini-jet, it makes it perfect for doing fine work in thin materials, such as jewelry. In the above picture, the tiny white line at the tip of the nozzle is the actualy waterjet stream doing the cutting. The nozzle would typically be cutting underwater and with splash protection around the nozzle, which was removed for this picture.
A 10-¼” steel part cut on a waterjet (photo courtesy of Jet Edge)
A common question asked about waterjets is “How thick can they cut?” The answer depends both on the material and how long you are willing to wait. The photo above shows a part cut on a waterjet from 10-¼” thick steel. Yes, it can be done. Below is a gear cut from thick steel.
A thick steel gear cut on a waterjet (photo courtesy of Jet Edge)
The following slightly goofy video provides a good overview of the waterjet cutting process. A few things to note about the video:
- They’re using an OMAX 55100, a medium-size waterjet
- Note the fixturing: there are several weights on the sheet of material to hold it down. Along the two edges are clamps that push against the side of the tank, keeping the material from moving sideways. In a piece as intricate as the one they’re cutting, this is particularly important, as any movement will cause a ragged edge.
- You can clearly see the slats that the material rests on (and these slats look fairly new).
- They make a “dry run” before making the part. A dry run has the head move along the cutting path without any water or abrasive and is a good way to make sure that the head won’t run into fixturing (the weights) or move off the material.
- The cutting is done under water.
- The nozzle is covered with a “muff”–a piece of sponge foam that reduces splashing, although it does hide the actual cutting, making the video less exciting.
- The reddish material you see on top of the material during cutting is garnet abrasive.
The picture below shows how waterjets can maintain accuracy over large distances. The stainless steel plate has 6,800 holes, each precision cut to a tolerance of ± 0.005″ by Arro-Jet Engineering and Consulting (read their case study [external link] on the Jet Edge web site).
Stainless steel 1/2″ thick baffle with 6,800 holes ± 0.005″ made for a heat exchanger (Photo courtesy Arro-Jet Engineering and Consulting)
Plexiglass® 1/4″ thick and 24″ x 24″ (Photo courtesy Arro-Jet Engineering and Consulting)
A 10 foot tall sculpture of a palm tree made from 1/8″ aluminum.
A custom waffle iron made from etched titanium. Required precision cutting and no room for error!
Xbox® case cutting
What happens when you use a waterjet on an Xbox case? Look at various logos and figures cut out of an Xbox.
Wooden electric guitar
Watch as a waterjet cuts out the pieces to make an electric guitar from wood.
Techniques for working with brittle materials, such as granite and marble.
When cutting laminated materials with a waterjet, you need to use some techniques to keep the water from getting between the layers and ruining the material.
A discussion about how to cut glass with a waterjet to minimize broken and chipped parts.