Waterjet and Laser Cutting: A Perfect Pair
To stay competitive, shorten lead times, and increase the markets they can serve, many laser job shops are adding abrasive waterjets to their machining equipment inventory. To uncover why the relatively new waterjet cutting method is gaining popularity with these traditional machining shops, let’s first take a look at how each technology works.
A laser cutter works by focusing a beam of high intensity light into a single pinpoint inside a nozzle where compressed gas is also flowing. The heat density at that single pinpoint is very high and results in heating, melting and vaporizing the material beneath it. Laser cutting is very accurate, leaves smooth edges, and is fast when cutting thin sheets of metal. However, laser cutting is limited to metallics, some plastics, some fiberglass, and some fabric. Reflective metals such as copper, brass and aluminum can bounce the laser light back at the machine, creating a safety hazard and potentially causing damage to the machine. Laser generates a heat-affected zone, which can distort some plastics and other materials. Laser cutting is generally only good for materials less than 0.25” (6.35mm), and 3D cutting is difficult because of the rigid beam guidance. If a workpiece contains a combination of materials with differing melting points, this can also present difficulty for laser cutting.
An abrasive waterjet cuts with highly pressurized water mixed with abrasive grit, typically garnet, travelling at supersonic speeds through a nozzle. The overall process is similar to erosion, but much faster and precisely directed. Waterjets can cut virtually anything, including combination materials and materials up to 12” thick. With waterjet machining, there’s no heat-affected zone (HAZ), so the material microstructure and properties aren’t altered. With an articulating cutting head, the edges of a waterjet cut part are square and smooth right off the machine. Equipped with an articulating cutting head and a rotary axis accessory, a waterjet can achieve 6-axis cutting for complex 3D shapes in tube, pipe and barstock.
Expanding into New Markets
It’s common for laser cutting shops to buy an abrasive waterjet to expand both the type and the thickness of materials they can cut in-house. During the recent recession, many laser cutting shops discovered it was deadly to depend on a volatile industry. Adding a waterjet allowed them to bid on jobs that included cutting thick metal, ceramic, glass, copper, brass, plastic and just about anything else. The increase in cutting capabilities led to a wider variety of jobs and a much broader customer base, which meant more work coming through the doors, and consistently. After seeing the orders increase, plus the flexibility and accuracy of waterjet cutting, many laser facilities have added a second and third OMAX waterjet to their mix. An OMAX waterjet is typically one-third or less of the capital cost of a laser cutting system.
A Shift In the Process Paradigm
Adding waterjet machining has also changed the workflow of some laser specialty shops, further increasing their productivity. OMAX waterjets are easy to set up and easy to operate without any special programming skills, so a new machinist can start making high-precision parts with just a few days of training. The OMAX CAD/CAM software works with over 90 different file types, so no time is wasted on lengthy file conversion processes. DFX files can be changed on the fly if a small change is needed for a run of similar but slightly different parts. Net blank and non-metal jobs are brought in-house so turn-around time is faster and there’s better quality control.
Incorporating the advanced technology of waterjet cutting is helping traditional machine tool shops stay afloat in today’s competitive manufacturing world.