• Waterjet Cutting is a process that uses a high-pressure stream of water to cut through a wide range of materials, including metals, plastics, ceramics, and composites. The waterjet cutting process is controlled by a computer program, which allows for precise cutting of a wide variety of shapes and sizes.

• The process of CNC waterjet cutting starts by pressurizing water to an extremely high pressure (typically 60,000 PSI or more) and passing it through a small nozzle. An abrasive substance such as garnet is often added to the water stream to enhance the cutting capability of the waterjet. The high-pressure water stream is directed at the material to be cut, and the waterjet erodes the material away, creating a clean and precise cut.

• The main advantage of CNC waterjet cutting is its ability to cut through a wide range of materials, including hard and brittle materials, without causing heat distortion. Waterjet cutting is also suitable for cutting materials that are sensitive to heat such as some plastics and composites. Additionally, waterjet cutting can cut a wide range of thicknesses, and it can create intricate shapes and cuts with high precision.

• On the other hand, CNC waterjet cutting has some disadvantages as well. One of the main disadvantages is that the process is relatively slow compared to other cutting methods such as plasma cutting. Additionally, the cost of waterjet cutting is relatively high because of the high cost of the equipment and the abrasive materials used.

• Another limitation of CNC waterjet cutting is the surface finish of the cut. The edges of the cut can be rough and require additional finishing processes such as polishing or sanding. Additionally, the process creates a large amount of dust and debris, which can be a hazard to operators and require additional cleaning.

• CNC waterjet cutting is a powerful technology that can be dangerous if proper safety measures are not taken. Here are some safety considerations for CNC waterjet cutting:

  • Eye injury: Direct exposure to the waterjet stream can cause serious eye injuries, including blindness. It is essential to wear appropriate waterjet cutting goggles or a helmet with a face shield when working with a waterjet cutter.

  • Cuts: The high-pressure waterjet stream can cause cuts and lacerations, proper clothing and personal protective equipment must be worn to prevent cuts.

  • Fire: Waterjet cutting can ignite flammable materials, proper housekeeping, ventilation, and material handling procedures must be in place to prevent fires.

  • Noise: The waterjet cutting process generates high levels of noise, which can be harmful to hearing. Proper hearing protection must be worn when working with a waterjet cutter.

  • Electrical hazards: The waterjet cutter is an electrical device and can pose an electrical shock hazard. Proper grounding and electrical safety procedures must be in place to prevent electrical shock.

  • Material handling: Material must be handled carefully to prevent injury. The material should be secured properly before cutting, to avoid any slips or falls.

  • Dust and debris: The waterjet cutting process generates a large amount of dust and debris, which can be a hazard to operators and require additional cleaning.

• To prevent injuries, it is important to follow the manufacturer's instructions and guidelines for the waterjet cutter, as well as to provide proper training for operators. Additionally, it's essential to have emergency stop buttons and fire extinguishers nearby and to be familiar with the emergency procedures. It's also important to conduct regular safety inspections and maintenance to ensure that the machine is in good working condition.

• The workflow for designing and cutting parts using a CNC waterjet cutter typically involves the following steps:

  • Design: The first step is to design the part using a CAD (computer-aided design) software. The design should take into account the material properties, thickness, and any specific requirements for the part.

  • Nesting: Once the design is complete, the next step is to arrange the parts on the material in an efficient way, this process is called nesting. Nesting software is used to optimize the use of the material and reduce waste.

  • Generating the G-code: The next step is to convert the design into machine-readable code, called G-code. This is done using a CAM (computer-aided manufacturing) software. The G-code is a set of instructions that the CNC machine will use to cut the parts.

  • Loading the program: The G-code is loaded into the CNC waterjet cutter's controller and the material is loaded on the machine's table.

  • Setting up the machine: Before starting the cutting process, the machine needs to be set up properly. This includes setting the correct pressure, cutting speed, and abrasive flow rate.

  • Cutting: The CNC waterjet cutter follows the instructions in the G-code to cut the parts from the material. The operator monitors the cutting process and makes any necessary adjustments.

  • Finishing: After the cutting process is complete, the parts may need to be finished, such as deburring or cleaning the edges.

  • Inspecting the parts: Finally, the parts are inspected to ensure that they meet the design specifications and are free from defects.

• It's worth noting that the workflow may vary depending on the specific requirements of the parts and the equipment being used. Additionally, there may be additional steps such as material preparation, clamping and fixturing, and maintaining the equipment that are necessary for the specific process.

Answer the following prompts/questions in your own words - apply your personal experiences and opinions to the topics covered in this sub-module. Feel free to use multi-media visuals, references, etc.:

1. What is Waterjet Cutting?

2. How does Waterjet Cutting work?

3. A) What safety considerations are specific to Waterjets?

B) What specific PPE should be worn when operating Waterjets?

4. What workflow steps are specific to Waterjets, and why?