Technical Tip - Maximizing Waterjet Orifice Life
As with any industrial equipment, there are certain components of waterjet cutting systems that are expended during operation. These consumables will need regular replacement to keep the machine running efficiently. In an abrasive waterjet, garnet will account for the bulk of consumable expenditure. However, both abrasive and water-only machines contain parts in the pump and cutting head that are constantly exposed to extreme conditions, causing them to eventually wear out. One such part is the waterjet orifice, a small metal disk containing a gem that focuses the waterjet stream. The orifice is vital to the operation of the waterjet as it enables the stream to reach the immense velocities required to cut hard materials.
There are three types of gems that are commonly used in waterjet orifices: ruby, sapphire, and diamond. Due to the considerable amount of stress they are put through, orifices will eventually fail regardless of the gem, but overall longevity varies between orifice type. Ruby and sapphire are very similar in characteristics such as hardness and life expectancy. Generally speaking, these gems will have an average life of around 40 hours. Diamonds on the other hand are a much harder gem. If used and maintained properly, a diamond orifice will last nearly 1000 hours. While these generally have a much higher upfront cost, savings are experienced through a significant reduction in machine downtime.
Regular replacement of the orifice is inevitable, but there are steps that can be taken to minimize wear and increase the life of the component.
Test the Quality of the Water
Testing your water to make sure it is free from any harmful chemicals or solids that could damage your waterjet is necessary before running the machine. A Total Dissolved Solids (TDS) meter should be used to ensure that the quality of the water is up to par. If viable for your application, aftermarket components such as WARDJet’s SmartCycle system are capable of recycling dirty tank water to be reused for cutting.
Invest in a Water Softener
Even after you determine that the quality of the water is good for your waterjet, we still recommend implementing a water softener system. When put under high pressure, hard water becomes very coarse and can be rough on consumable machine parts. This untreated water can also cause scaling to build up on the inside of ultra-high pressure (UHP) lines. Debris can then break off of the scaling and cause damage to the orifice itself. Integrating a water softener can reduce the possibility of damage to the lines.
Use an Inline Filter
An UHP inline filter can be installed right above the orifice inside of the nozzle. This filter will catch any type of debris that might come from the UHP lines or even the water itself. The filter should be checked regularly for damage and replaced when necessary to preserve orifice longevity.
Properly Seat the Orifice
After replacing an orifice, start building water pressure from zero to high pressure slowly. First, ensure the area is safe and then turn the cutting head to the on position with the abrasive turned off. Next, set the pump to low pressure and turn on the pump. Once low pressure is reached, cycle the cutting head on and off several times. While the cutting head is still open, increase the pump to high pressure. Again, cycle the cutting head on and off several times in high pressure. Make sure the cutting head is open any time the water pressure increases.
Always Replace the Orifice at a Workbench
Replacing an orifice involves stripping down the cutting head to gain access to the parts inside. These parts are very small and can be easily dropped and lost in the tank of the waterjet. Finding a component that’s smaller than a dime in a large tank full of water, abrasive, and waste material is no easy task, and the cost to replace lost parts, especially diamond orifices, will detract from your bottom line. This is why we recommend always working on the cutting head at a workbench away from the waterjet to avoid the possibility of losing consumable parts in the tank.
Always Work Clean
When replacing an orifice, make sure that the work environment is clean and free of debris. Washing your hands prior to replacement is suggested in order to prevent contamination of the orifice.
Flush the Lines
The (UHP) lines used in waterjet cutting systems need to be coned and threaded on each end to be able to transport the pressurized water to the cutting head. This process can cause stainless steel debris to get into the UHP lines which can then be carried through the system and forced down into the orifice, causing major damage. To prevent this from happening, the entire system should be flushed. With no orifice installed, cycle the water on and off, first at low pressure, then at high pressure in order to clear the system. Do this multiple times until you are comfortable that there is no debris left inside of the machine. The orifice can then be reinstalled and cutting resumed. Repeat this process for both new machines and machines that have had the UHP lines replaced.
By following these tips, machine downtime and overall consumable costs can be effectively lowered. To purchase replacement parts including orifices and nozzles, visit our website at https://wardjet.com/waterjet/parts or email parts@wardjet.com. For any questions concerning waterjet maintenance, feel free to contact us at 1-844-WARDJET or send us an email to sales@wardjet.com.