An abrasive waterjet machine’s monitoring know-how, coupled with good upkeep practices, helps maintain the operation productive, clean, and uneventful. Photos: OMAX
Abrasive waterjet reducing has a plethora of benefits. The cold-cutting course of eliminates the heat-affected zone on the minimize edge. It cuts excessive thicknesses with excessive precision, a lot in order that the reducing technique usually replaces or eliminates the necessity for secondary ending. And, in fact, the method can minimize any materials, not simply metallic.
When maintained and monitored correctly, abrasive waterjet machines minimize persistently and reliably. When upkeep is ignored, the other happens as unplanned downtime accumulates.
To debate the fundamentals of upkeep and among the newest in monitoring strategies, The Fabricator spoke with Ivan Kondeykin, territory gross sales supervisor at OMAX. His general message: If operators know precisely what makes the method dependable and benefit from what trendy course of monitoring know-how has to supply, they’ll decrease the sudden and catch points nicely earlier than they snowball into bigger issues.
Consumable Put on
Abrasive waterjet includes excessive pressures, so part put on is pure and unavoidable. Kondeykin prefaced his perception on part life with a giant caveat: Actual-world consumables life varies considerably, relying on how the machine’s used.
To grasp why, it helps to think about waterjet reducing backward, beginning the place the blended water-and-grit stream hits the fabric floor. Transfer up from there and also you see parts on the entrance line of damage: the mixing tube and nozzle.
“These get pummeled by water and abrasive,” Kondeykin mentioned. “They will final wherever between 50 and 120 hours, relying on what you’re reducing and the way you’re reducing.”
Behind, although nonetheless very near, the entrance line of damage is the diamond jewel orifice, which shapes the high-pressure water stream simply earlier than it mixes with abrasive. These can final for 500 to 800 hours of reducing or so, relying on the appliance. Then there’s the part that creates the stress you want—the pump itself. The pump’s high-pressure sealing parts sometimes require service after roughly 1,000-plus hours, relying on working circumstances.
“Greatest practices contain following a daily preventive upkeep schedule,” changing components nicely earlier than they fail, Kondeykin mentioned. “Admittedly, some operations simply push issues till they break. That, in fact, isn’t superb.”
Thoughts the Pierce
How a nest of components is minimize impacts part life considerably. Lengthy cuts with few pierces can prolong part life. Slicing perforations and different geometries with vital numbers of piercings can put on parts quicker. This is sensible when you think about what occurs when water and abrasive carry out a pierce.
“Water will all the time discover a approach,” Kondeykin mentioned. “Say you’re piercing 4-in.-thick stainless-steel. When you want to pierce a gap, the water and abrasive has nowhere to go however up. It assaults the nozzle whereas the nozzle tries to assault the fabric. The reducing vitality displays again till you penetrate fully by the fabric.”
He described one utility involving an enormous nest with a number of pierces. After re-examining the toolpath technique, the operator switched to a steady toolpath utilizing edge begins and lengthy, constant cuts by the thick materials, no piercing required. As a result of the machine remained in a gentle, steady minimize, upkeep intervals may very well be prolonged considerably.
A monitoring platform tracks the water provide temperature, filter pressures, and different processing variables.
Typically, a lot of pierces simply isn’t avoidable, like when reducing screens or creating perforated options inside a component. Even in these circumstances, waterjet may nonetheless be the method of alternative, particularly for heat-sensitive materials. However there’s no getting round physics: Continuous piercing will put on all parts quicker—a incontrovertible fact that must be baked into the PM schedule.
Thoughts the Abrasive Hoppers
Waterjet machines normally have two hoppers: a bulk one that may maintain hundreds of kilos of abrasive grit, and a small one which holds between 7 and 10 lbs. of grit sitting proper behind the reducing head. As Kondeykin defined, the small hopper typically acts as the first abrasive supply when, say, somebody is utilizing a desk for one-off components or different intermittent makes use of. It would should be stuffed each 5 minutes or so, however should you’re solely reducing a handful of items, then relying solely on that small hopper could make sense.
Usually, although, the small hopper acts as a buffer each time abrasive stops feeding from the majority hopper, giving the operator a couple of minutes to revive provide. The majority hopper may have a scale exhibiting how a lot abrasive is left. However when a store will get busy, particulars get missed, together with the standing of abrasives within the hopper.
Simply because abrasive isn’t flowing doesn’t all the time imply a hopper is empty. As Kondeykin described, waterjet retailers usually fireplace up a machine within the morning, solely to search out the machine’s run out of abrasive a couple of minutes into the primary job. The buffer tank is empty, but the majority hopper is full. What offers? “Typically, we see individuals by chance turning off the store air going to the majority hopper.”
Thoughts the Water Supply
“It sounds apparent, but it surely occurs,” Kondeykin mentioned. “Operators see a sensor fault out a machine, and so they’re questioning concerning the trigger. Finally, they discover out that somebody forgot to activate the water. It’s sort of like discovering out your automobile doesn’t run as a result of it has no fuel.”
In fact, the problem may reside exterior the manufacturing unit partitions. Typically the town turns off the water briefly, which in fact may cause points for a waterjet job store. “We don’t essentially catch it in our houses in our day-to-day life, as a result of we don’t have the water working on a regular basis. Nevertheless it occurs periodically.”
One other necessary issue is water temperature, notably in hotter climates. Whereas waterjet methods can function with hotter inlet water, cooler water usually helps maximize part life. Chillers keep the water at an optimum working temperature, sometimes between 45 and 50 levels F.
“Sure high-pressure sealing parts are extra prone to put on as water temperature will increase,” Kondeykin mentioned, including that strategic placement of pipes may help, particularly in hotter climates.
Correctly sized chillers clear up the water temperature challenge, but when a waterjet system doesn’t have one, or if a chiller is undersized for the appliance, some monitoring and commentary are so as. If water strains run alongside the plant ceiling, attain the wall, and solely then descend and go underground to attach with the power provide strains, then water temperature could be a difficulty, particularly if the pipes aren’t insulated.
“When an operator arrives within the morning or returns from lunch, and the waterjet hasn’t been working, you might need water temperature points,” Kondeykin defined.
Machines routinely cease if the water provide descends to a sure threshold. Kondeykin added that some operations in areas with vital water provide disruptions may set up their very own water tanks to make sure their machines maintain reducing. Some even set up rain assortment tanks, particularly these vegetation situated in areas with a wet season, like South Florida in the summertime or the Pacific Northwest within the winter. This final technique can enhance reliability whereas additionally saving on the month-to-month water invoice.
In fact, whether or not retailers spend money on storage tanks will depend on the scenario. Trendy methods account for slight water stress modifications. Mix this with monitoring and software program (extra on this quickly), and the general influence of water provide points could be minimal.
Develop a Upkeep Technique
Sensors and monitoring software program may help improve and optimize these upkeep fundamentals. For instance, Kondeykin described OMAX’s IntelliVISOR platform, which presents course of monitoring accessible through telephones, tablets, and laptops.
The data the platform supplies is available in two classes: real-time standing monitoring and utilization monitoring. The previous exhibits the present state of operation, measuring pressures, filter standing, and different knowledge. The latter exhibits what number of hours sure parts have been used and when they need to be modified. Kondeykin really useful a conservative strategy. Utilization trackers merely measure hours of use for numerous parts, together with cylinders, liquid displacers, plungers, and manifolds. “An excellent operator will learn this info and suppose, ‘I’ve obtained 20 hours left on this part. That doesn’t imply it’s going to fail in 20 hours; it’s simply the really useful window to interchange it. However I’m about to start out an extended manufacturing job that can contain 50 hours of nonstop reducing.’”
Ideally, operators monitor these really useful alternative home windows based mostly on utilization. If a machine is pushed laborious—with repeated, heavy piercings on almost each job—optimum part alternative home windows may very well be shorter.
Alternatively, if jobs have few piercings and contain simply lengthy, constant cuts, these really useful alternative home windows could be good as they’re. “Parts don’t fail at a precise hour,” Kondeykin mentioned. “They may all the time last more than their really useful use. However you all the time wish to be on the protected aspect.”
Alongside this comes real-time monitoring. Sensors measure numerous parts, together with the pump motor RPM in addition to water stress on the filters, each the one earlier than the pump and the ultimate filter simply earlier than the water travels to the reducing head. As soon as the stress differential between the 2 filters reaches 20 PSI or extra, the filters ought to be changed.
Sensors monitor the inlet and outlet stress repeatedly, and operators can monitor the place issues stand and be proactive. “You actually don’t wish to be caught midway by a job and discover that your filters are clogged up,” Kondeykin mentioned. “Operators can see that the filters are approaching no matter window they’ve set and exchange them earlier than the job begins.”
Sensors additionally monitor incoming water temperature and flag the problem if the temperature rises an excessive amount of. This helps operators catch chiller issues early. Or, if a machine isn’t linked to a chiller, the warnings assist catch pockets of heat water that could be current, particularly when working the primary reducing job of the day. Seeing that the water is simply too sizzling, operators cycle the machine to flush the nice and cozy water that has been sitting within the constructing’s piping and exchange it with cooler incoming provide water.
A vacuum sensor straight on the nozzle detects abrasive loss, triggering a right away pause in reducing. It does the identical when it detects a clogged nozzle. “That is uncommon,” Kondeykin mentioned, “however it may possibly occur. You possibly can have poor-quality abrasive, or some overseas object made it into the system, or some materials might need floated up into the nozzle opening. If the nozzle turns into blocked, the water will search one other path, which might pressure water again by the abrasive feed tube.” The vacuum sensor, triggering a right away shutoff, prevents this from taking place.
Being Proactive
Sensors observe the temperature of electronics, the state of servomotors, the fan on the cooling system, pump stress and common pump standing, and myriad different parts. The data additionally could be fed into broader manufacturing management software program and IIoT platforms.
All this helps retailers take advantage of out of their waterjet methods. It additionally may help guarantee finest upkeep practices are optimized—based mostly not on assumptions, however on actual knowledge.
