Waterjet Pressures Are Increasing, And So Is Productivity
With its new X-Stream xP90-100 Waterjet Intensifier Pump, Jet Edge Waterjet Systems is able to reach higher pressures “than we were able to achieve with previous models,” says Jeff Schibley, Great Lakes regional manager.
Pressure is not all that important until a job shop is trying to produce parts better, faster and less expensively than their competitor. This is how you win work in a job shop industry he mentions.
“What we found is that by increasing operating pressures to 90,000-PSI peak pressure, which really produces about 75,000 PSI continuous pressure, we’re able to increase cutting speeds by about 40 percent in a lot of materials without increasing the flow of the garnet cutting material in the process.
“If we’re cutting a 0.5-in.-thick-aluminum part using the same amount of garnet per minute in the cutting head, because we’re cutting a part faster with higher pressures, we end up using less abrasive to cut the actual part. Let’s say this part took four minutes to cut at 55,000 PSI and we were using 0.6 pounds per minute of abrasive. This uses 2.4 pounds of abrasive to cut a part that takes four minutes to cut at 55,000 PSI.”
Using extreme pressures, Schibley says they can now cut this part about 40 percent faster. They’ve reduced its cycle time to about 2.4 minutes using 0.6 pounds of abrasive per minute. Now only 1.8 pounds of abrasive is used.
“This typically makes job shops more competitive, because they’re able to cut faster than someone down the street that’s using a waterjet with a lower pump pressure,” he says.
Asked about equipment modification to handle these higher pressures, Schibley says that it requires an upgrade of an existing intensifier. “Any job shop that is currently using waterjets operating in the 55,000-PSI range could purchase one of our intensifiers and our higher pressure plumbing components, this would give them the ability to increase productivity,” he comments.
With a 50-hp intensifier, a Jet Edge Waterjet generates 1.1 gallons of water per minute at 55,000 PSI. Using extreme pressures, it goes from a 20-to-1-compression ratio meaning that it has 20 times greater area for the hydraulic piston than the high-pressure water.
But when extreme pressures are used, the intensifier is at 25.5 to 1. It has 25.5 times greater area on the hydraulic piston than the high-pressure water system. Therefore it produces less volume of water for the same electric energy and horsepower.
At 1.1 gallons of water per minute, this allows the waterjet to accelerate 1.3 pounds per minute of abrasive with 50 hp and 55,000 PSI. This uses 78 pounds of abrasive in an hour at 50 hp with 50,000 PSI. Using extreme pressure, abrasive usage drops to 0.7 pounds of abrasive at just 42 pounds per hour. This allows the same amount of work while using less abrasive, Schibley remarks.
Service for this type of high-pressure pump is also important. Schibley says that their X-Stream xp90-100 intensifier is completely serviceable by the end-user using many standard tools bought at a tool store.
“We accomplished this using some very unique torque amplification bolts that allow the use of standard ratchet sets for torquing the cylinders to the proper specifications without buying special tools,” he concludes.
There are several areas that Flow waterjets have focused on recently says Tim Fabian, waterjet product manager. The first is the company’s Dynamic XD Technology that greatly expands its waterjet capabilities by offering 3-D cutting. Second is an industry trend of higher waterjet pump pressure’s of 94,000 PSI.
“We emphasize the universally accepted fact that pressure equals productivity,” says Fabian. “This allows less garnet to be used in the cutting stream. When you do a much more effective job of accelerating the abrasive, you don’t need as much of it.”
Asked if these extreme pressures could be problematic, Fabian says, “No, not really. It would be the case when this technology was in the development stages, but we will not release a product unless it has the same maintenance characteristics of our lower pressure pumps. In fact, we currently produce pumps that have 120,000 PSI output, but not for the metal fabrication market. It would even work with pumps that have pressures over 140,000 PSI. So our 94,000 PSI pump is very robust and reliable.”
Another benefit of using less garnet for cutting is lower maintenace costs and less downtime. The waterjet will not need to be cleaned out as often. “It also means less handling of abrasive and less freight,” remarks Fabian. “We look at abrasive as being 60 to 65 percent of a system’s operating costs. If you can reduce this by 30 to 35 percent that goes a long way and impacts the bottom line. This is the most significant benefit.”
Another big focus that Fabian says they’ve had recently is to work on the big disparity between premium waterjet suppliers and some integrators that take parts from companies and put together a waterjet system. “Since we are a sole-source supplier of everything, we tend to look at the complete package, and we are a lot more focused on the system being a good citizen in a shop. This means we design our systems to minimize spray, reduce any type of mess, and we really take a lot of steps for user convenience, making it a pleasurable machine to run.”
Jeff Day, sales manager for WARDjet waterjets, mentions that although they have a full line of standard waterjets, they are doing more work in the customization area.
“For instance, If a customer needs an inkjet printer to mark the materials before their waterjet cuts it, or they need shuttle tables or some other type of material handling to get material on a table faster, this is a big area of growth for us,” he says.
WARDjet is also noted for its five-axis-waterjet-cutting sytems. These can often help minimize downstream applications because of their versatility, Day mentions. “For instance, they can put 45-degree angles for bevel cuts for downstream welding processes.”
Day also remarks that they’re seeing customer interest in ultra-high-pressure waterjet pumps in the 90,000 PSI range, and the company offers these pumps. “But, we’ve been able to do certain proprietary things on our machines that help make them extremely competitive with these high-pressure pumps without having to purchase one. With our 60,000-PSI pump, customers are able to approach the speeds of the 90,000-PSI ones, he says.
“We do sell the ultra-high pressure pumps, but we always want to tell people the pros and cons for the consumables which will end up being extremely expensive. You tend to be a captive audience when you buy the ultra-high pressure pumps, and you can only buy the consumable items from the manufacturer. With a low-pressure pump, there are plenty of third-party-consumable manufacturers that keep consumable-part prices in line. In the end we feel that most customers look at the 60,000-PSI pump as a more cost effective solution.”
WARDjet has recently built a machine that has eight cutting heads on it using two 100-hp, 60,000-PSI pumps on it. “Whether somebody wants a small machine with one head, or a machine with up to 15 heads, we can put the appropriate sized pump or pumps on it,” says Day.
“This is one area of growth that we see in the market. It’s also an area that other waterjet manufacturers aren’t necessarily pursuing,” he concludes.
Techni Waterjet offers a unique pump that doesn’t use a hydraulic system mentions, Mike Burns, president. “I think our biggest new product introduction has been our Quantum ESP Pump. ESP stands for electric-servo pump. It’s the first high-pressure waterjet pump in the market to utilize an electric servomotor for the power rather than a hydraulic system.”
For years waterjets used a hydraulic pump to pressurize hydraulic fluid that powered a plunger mentions Burns. On the other side of the plunger was the pressurized water used for cutting. Techni has replaced the hydraulic power supply using an electric servomotor.
This accomplishes several things: It’s very quiet. It has far fewer maintenance issues than a hydraulic system, and it has better performance, because you can control the motor much better than just using a hydraulic valve that is either open or closed.
“With our system we can actually program the servo to be pumping at a specific force/time acceleration curve that offers better pump performance. Thereby getting a better pumping signal and better component life,” says Burns.
One of the main complaints over the years with a hydraulic pump was the consumption of power and water were simply too high mentions Burns. Unlike a hydraulic system that will always be drawing electricity at a high rate even at idle, the servo-electric pump will dramatically reduce its amperage draw during idle, eliminating any wasted energy.
“Hydraulic systems only have about a 60-percent, wall-plug power efficiency. With a 100-amp service, most of it is going down the drain in hot water and cooling water. With our electric pump, one of the main advantages is that it’s almost 60 to 70 percent more efficient than a hydraulic one.
“It only requires 40 amps of wall-plug power, and what’s coming out of the waterjet nozzle for production is the equivalent of 35 amps. With a higher efficiency, you aren’t wasting electricity and water going down the drain in heat and cooling the heat.
“Our cooling water is about one gallon per minute as opposed to the three to four gallons per minute for a hydraulic system. Our biggest advantage is that it costs less to run the system for the same output.
Techni Waterjet’s Quantum ESP Pump has a small footprint that is about half the size of a comparable hydraulic system says Burns. It operates at 68 decibels where previous hydraulic pumps operated between 76 to 78 decibels. There have also been performance improvement enhancements such as longer seal life and longer component life due to the better performing high-pressure signal.
“Our design allows us to change seals in under four minutes,” remarks Burns. “This is a record-breaking time, because the older hydraulic units would take 30 to 40 minutes or even longer.
Techni offers a number of standard waterjet models with pressures ranging anywhere from 55,000 up to 90,000 PSI. They can retrofit other waterjets with their electric-servo-pump system.
“For performance versus price, Bystronic waterjets are some of the best available,” mentions Brody Fanning, waterjet product manager.
“Bystronic’s niche is high productivity and accuracy with a large format machine,” he says. “When a customer needs a high productivity machine with the ability to run three shifts with high-accuracy part requirements along with a large-bed machine, like 10 ft. by 20 ft., then the Bystronic machine is very competitive.”
One of Bystronic’s main niches is in untended and/or high productivity operations. They can also design systems to handle large-material-sheet sizes.
“We can develop our machine to have multiple heads, so they can double or triple productivity,” Fanning mentions.
Bystronic machines are equipped with height sensors along with other standard sensors that will detect process interruptions and stop the machine when they occur. This allows an operator to walk away from the machine to perform other tasks saving labor.
Bystronic machines are equipped with CNC-controlled abrasive metering that provides accurate control of the abrasive cost, the most expensive component of abrasive waterjet cutting cost of operation.
Fanning mentions that although some waterjet manufacturers offer some of the features to make their machines run in a lights-out manufacturing situation, “none of the manufacturers offer all of them, and none as standard equipment, as Bystronic does.”
Showcased at IMTS 2010, OMAX Corporation’s 80X JetMachining Center has a footprint of 265 in. by 152 in. It’s equipped with Intelli-TRAX, an innovative traction drive that ensures high accuracy and expands the cutting envelope in increments of about 6 ft., mentions the company’s press release. With a fully enclosed drive inside coated-steel covers, the 80X is a robust and reliable system suited to harsh environments and requires little maintenance. It offers fast traverse speeds greatly reducing throughput times when machining multiple and nested parts.
The 80X JetMachining Center features an X and Y cutting travel of 165 in. by 80 in. and comes standard with OMAX Intelli-MAX Premium Software that runs on the Windows XP operating system. The system can calculate the precision of a tool path at over 2,000 points per inch, allowing for complete control over the motion of an abrasivejet and enabling precise, rapid machining the company says.
Standard features include a programmable, motorized Z-axis with a precision OMAX MAXJET 5i long-life, integrated diamond-nozzle assembly, ultra-high-pressure direct-drive pump and rapid water-level control. It has the ability to cut a wide variety of materials with an accuracy of motion up to +/- 0.003 in.
Jet Edge Waterjet Systems