Waterjet 101 - Waterjet Motion Systems

Waterjet Motion Systems

A typical waterjet motion control system includes a motion control table, an ultra high pressure (UHP) intensifier pump, a computer-based waterjet controller, tools, and options such as an abrasive delivery system or an abrasive removal system.
 
 
waterjet motion system
 

Motion Control Table

The motion control table is a structure that allows a waterjet to be moved in a controlled fashion. The size of the structure determines the size of a work envelope (the area the waterjet can move within). A waterjet is mounted to a z-axis that can move up and down. A cross beam supports the z-axis and allows a waterjet to be moved side-to-side (also called the x-axis). Side beams support the cross beam and allows the waterjet to move front-to-back (also called the y-axis).
 
The structure straddles a catch tank (not shown) that collects the water and debris from cutting processes. A controller provides the operator interface and controls all of the machine components. The operator interface is a computer software program.
 

Intensifier Pump

The intensifier pump produces UHP water up to 75,000 psi (5170 bar) for use by waterjets, abrasivejets, and other tools. The UHP water supply is routed from a high pressure plumbing assembly to the z-axis through a UHP whip that allows it to follow the waterjet movements. The UHP water is connected to the waterjet where it is focused for cutting.
 

Tools

Tools include waterjets, abrasivejets, rotary orifice manifolds, and drills. Tools are mounted to the z-axis carriage; when more than one tool is used the tools are mounted to a spreader bar. Multiple tools allow multiple parts to be cut simultaneously.
 

Abrasive Supply

Abrasivejets require an abrasive supply system. An abrasive hopper is pressurized to help the abrasive flow through flexible tubing that is routed along the UHP whip to the z-axis. A mini hopper mounted to the z-axis meters the abrasive to the abrasivejet where it is mixed with the UHP water.
 
 

Cut Without Heat
Jet Edge waterjet technology is ideal for cutting heat sensitive material. Costs due to thermal distortion of machine parts are eliminated. Risk of fatigue failure resulting from process induced thermal stressing and associated material structural change is minimized.

Accurate Cutting
Jet Edge waterjets can hold an accuracy of 0.005 inch with a repeatability of 0.001 inch over the entire work envelope.

No Sharpening Required
Unlike conventional cutting tools, waterjets cut with a supersonic stream of water that never dulls. With waterjet, you will never need to shut down to sharpen or clean blades.

Minimize Dust and Toxic Fumes
The practical elimination of airborne dust particles, smoke, fumes, and contaminates from cutting materials such as asbestos and fiberglass greatly improves the work environment and reduces problems arising from operator exposure.

No Finishing Operation Required
Selection of appropriate cutting parameters such as operating pressure, material feed rate, abrasive particle size, and flow rate can eliminate the need for secondary operations. Jet Edge systems also reduce machining time and production costs.

Non-Contact Cutting and Cleanliness
USDA approved equipment designs promote the use of ultra-high pressure waterjet streams in the sanitary cutting of food products. Using UHP waterjet results in higher cutting speeds and the elimination of associated downtime incurred for cleaning and resharpening delicate blades. One of the biggest advantages is that fixturing associated with other machining methods is minimized.

Near Zero Lateral Cutting Force
Jet Edge waterjet systems reduce fixturing costs plus avoid excessive stress to finished parts. Also, minimal lateral force simplifies material handling and allows cutting close to material edges.

Minimum Waste Material
With typical orifice diameters in the range of 0.003 – 0.030 inches, waterjet kerf width is kept to a minimum, thus maximizing material utilization.

Omni-Directional Cutting
Waterjet cut profiles are not confined to straight-line geometries. Part complexity is limited only by the motion control system specified and traditional start holes are eliminated.

Environmentally Friendly
Waterjets produce no hazardous waste, reducing waste disposal costs.  They can cut off large pieces of reusable scrap material that might have been lost using traditional cutting methods.  Parts can be closely nested to maximize material use, and the waterjet saves material by creating very little kerf.  Waterjets use very little water (a half gallon to approximately one gallon per minute depending on cutting head orifice size), and the water that is used can be recycled using a closed-looped system.  Waste water usually is clean enough to filter and dispose of down a drain.  The garnet abrasive is a non-toxic natural substance that can be recycled for repeated use.  Water Jet Garnet usually can be disposed of in a landfill.