One of the foremost advantages of waterjet cutting over other common cutting methods is the ability to cut extremely thick materials. Waterjets are generally only limited by the maximum height of the cutting head. While it is possible to cut materials of nearly any thickness, there are precautions that must be taken when cutting thick materials to avoid damage to the workpiece. Preparation is paramount to the success of the cut. Once the cut has begun, any changes made to the machine can have an effect on the quality of the finished workpiece. Follow these steps to prepare your waterjet cutting machine for the job.
Check the Nozzle for Wear
A worn out nozzle will increase the diameter of the cutting stream and can result in a part that is out of tolerance. For best results, install a new nozzle before cutting.
Use a Diamond Orifice if Possible
A diamond orifice has a much longer lifespan than that of a ruby or sapphire orifice. While ruby or sapphire orifices will last less than a hundred hours, a diamond orifice can last up to and sometimes even more than 1,000 hours. Generally speaking, the thicker the material, the longer the cut. Certain jobs can require the waterjet to run nonstop for days at a time. The last thing you want to find when coming back to a job that has been running overnight is that the orifice has blown and the part is now ruined. Utilizing a diamond orifice will minimize the risk of a blown orifice when cutting thick materials. For tips on getting the most out of your orifices, read our blog post, "Maximizing Waterjet Orifice Life".
Image courtesy Cutlass Engineering
Use Coarse Abrasive
Lower mesh abrasive will be much coarser than high mesh abrasive. When cutting through thicker workpieces, 60 or 80 mesh abrasive will be much more efficient than 120 or 150 mesh. Load the hopper with a low mesh abrasive, being sure to clear the hopper of any leftover abrasive before adding that of a different mesh.
Ensure There is Enough Abrasive in the Hopper
Thick workpieces can take a long time to cut. The longer the duration of the cut, the higher the abrasive usage. While cutting with water only is possible for softer materials, running out of abrasive while cutting hard workpieces will result in the material being etched rather than cut all the way through. Before commencing a lengthy waterjet job on a thick workpiece, check that the abrasive in the hopper is sufficient. WARDJet offers several bulk feed hoppers that store anywhere from 200 – 4400 pounds of abrasive, reducing the possibility of abrasive depletion during a cut.
Confirm the Part Will Fit
Load the program and use the controller software to jump to cut points that are close to the edge of the material. Confirm that the cutting head never leaves the material to be sure that the part will fit on the workpiece.
Cut a Test Part Out of the Material
Program a small part that has the same features as the actual part (inside corners, outside corners, radii etc.). Cut this small part out of the material to ensure that the features are on par with the desired cut quality. If the cut is not sufficient, make adjustments to the machine and try the cut again until the desired quality is reached.
Cut Underwater if Possible
By raising the level of the water in the tank (or lowering the grates) it is possible to cut a thick workpiece completely underwater. Cutting underwater can drastically reduce the amount of splashback and noise level associated with cutting, as well as the possibility of frosting the top side of the workpiece.
By following these steps and preparing the waterjet before the cut, an operator can minimize the risk of ruining a thick workpiece. For more information, fill out our contact form.