Bring Some Grit to the Game
May 22nd 2020
Whether it’s our favourite hockey players or the star of the next big action movie we all love a little grit. Waterjet cutting is no different. For many types of cuts and materials being cut, the addition of abrasive materials is not only helpful but at times the only way to make the cut.
Without adding particulate matter, high pressure will only get you so far. Modern waterjet technology infuses the cutting spray with abrasive grit. This now creates a cutting combo that takes the waterjet’s abilities above and beyond what other cutting options can offer. The result? Metal surfaces quickly erode from the power-packed particle stream. Think of it as a precision liquid file flying through the material being cut.
However, not all abrasives are made equal. Different types of abrasive material and sizes are infused into the cutting process depending on what is being cut. Experienced technicians know how much and which abrasive particulate matter to use for each job.
Like a Hot Knife
Part of the reason we love waterjet cutting is that it is one of the most environmentally friendly ways to machine and manufacture items. It consumes far less power than others and for many soft materials like meat, paper and soft woods, all that is needed is concentrated high-pressure water (we’ll talk about how waterjet is changing the food processing industry in a later blog post), making it a very clean cutting process.
For soft materials, water cuts through with ease! The simplicity and cleanliness of pure waterjet cutting is wonderful, but it can stall out on many cuts of harder/denser materials or when cutting something that is highly technical or intricate. That is where the use of abrasives are brought in.
Under the Microscope
You might be familiar with sandblasting, however, waterjet uses a very different and more refined type of material for its abrasives. One of the most popular particulates used is granulated garnet. It is an extremely hard substance that can be easily milled to the various sizes needed for the cutting process.
This ability to be sized is extremely important for its use in waterjet cutting. The particulate size or, technically speaking, its ‘mesh grade’ greatly affects all aspects of the cut. Mesh size affects everything from what materials can be cut, to the depth of the cut, to the intricacy of the cut right down to how polished or smooth the cut is.
An experienced waterjet technician knows the pros and cons of which mesh size (if any) to use. It’s never a linear choice as there are many variables to consider in making this choice.
Cost: All raw materials cost money from the water being used, to the electricity being drawn, to the wear and tear on the waterjet nozzles, and the size of the grit being used; everything plays a factor in the rates a shop charges for a particular job. Finer grits cost more money which can make mesh selection vital in delivering a cost-effective and profitable service.
Speed and Accuracy: Larger particles cut faster but oftentimes with a larger cut (kerf) leaving a less refined edge. Finer mesh tends to cut slower but leaves a smoother finish and a more refined finished product. Slower cuts mean more abrasives used meaning that costs can rise but a more refined edge could mean less time spent finishing the product.
Wear, tear, and performance: The right grit size needs to be chosen along with the right diameter of the cutting orifice for the waterjet. If these two items are miss-matched it can cause clogging and increased wear and tear of waterjet parts. Clogs cause machine downtime which can hold projects up and keep a shop from running effectively. Production can be brought to a halt because of a few grains of garnet.
Human After All
Modern waterjet cutting is a precise process. Robots and other technological advancements have automated the process, but having a skilled operator making the decisions on what type and size of grit to use for your particular project is key to getting accurate and timely results. Abrasives are often the make or break decision of how refined a finished product will be.
Bringing grit to the game will help your next project take shape! Find out more about how Niagara Waterjet uses abrasives on your next project. Call or email us today to get started.