Predict
& prevent

Manufacturers find measurable results by keeping their machines well maintained

Predict
& prevent

Manufacturers find measurable results by keeping their machines well maintained

lan your work for today and every day. Then work your plan.” This advice from the late British Prime Minister Margaret Thatcher distills the importance of having guidelines to clarify the competing priorities that tug at each one of us every day. Without a strategy, routine tasks like preventive maintenance (PM) can be neglected. However, it’s a lot easier in the long run to take steps to keep equipment in smooth working order because unplanned downtime and expensive costs are never part of the plan.

Mike Robinson, customer service supervisor at OMAX Corp., says that “every one” of the Kent, Washington-based waterjet manufacturer’s customers who have instituted a PM program for their equipment “has found some measure of good results.”

He cites one customer that already had a PM program in place but then “hired a new maintenance manager who incorporated better tracking of consumption to help him predict the maintenance needs, which allowed him to schedule time on the machines before they went down. They almost never were waiting on parts for a down machine. Rather, they had already ordered them and had them on hand before the failure. This drastically reduced machine downtime and saved a lot of money.” Robinson notes that this same maintenance manager took another step to save money and time: he rebuilt the swivels—a part that allows the waterjet cutting nozzle to travel across the table surface—in his office. “When one needed to be rebuilt, he would swap it with the one on his desk,” and prepare the other part for the next time, which means the machine never runs with a leak.

Back to basics

Anyone and everyone can and should have a PM program, Robinson says. An easy place to start is by running through the tasks listed in the startup procedure located in the manual, including basic items like checking the Adjustable Dump Orifice (ADO); setting the cut pressure; rotating the mixing tube; auto homing the bridge; rotating slats; making test cuts to measure kerf; measuring the abrasive flow; and double checking the settings in the software.

Properly maintaining the stainless steel slats that support the material ensures a flat surface for accurate cuts.

“There are a few tricks to get more out of your machine, but to keep it running smoothly, just follow the book,” he says. The ADO and the Auto Home Sequence are two important items that users often overlook. The yellow knob on an OMAX pump corresponds to the ADO, which adjusts the dump pressure on the pump. “You want to get close to your cutting pressure without going over it—and you don’t want to be so close that any natural deviation in the pressure causes you to fault out,” says Robinson. “The normal issue we encounter is that it was set weeks or months ago, and when we check, it is completely open. This affects the pump by creating a sort of water hammer that sloshes back and forth in the high-pressure components, causing these parts to fail prematurely.”

Schedule maintenance like it is a job you are going to cut. It will pay off in machine up time.

mike robinson, omax corp.

Homing the machine daily will help ensure precision. The homing process establishes a location on the machine’s cutting table where the nozzle can be removed in a repeatable way. “It may seem boring sitting there for a couple minutes waiting for the machine to stop thinking, but the Auto Home Sequence is vital,” Robinson says. “It is how we set our zero/zero coordinate—how the machine knows where the corner of the table is so it knows how far it can go.”

Once the waterjet is ready and cutting, it’s also important to pay attention to the slats. Often, parts are continually placed on one section of the table, such as the bottom left corner because it is closest to the controls. As a result, the slats can develop uneven wear and begin rocking during cutting, reducing accuracy.

Precision waterjet heads require calibration on a level surface. This process won’t work correctly on worn slats.

“The slat doesn’t just support the weight of the material to be cut, it also helps to hold it steady while it is being cut,” Robinson says. “As the material is cut away, the slat is also cut away, and as that happens, the slat starts to look like teeth. Eventually, only the sharp, pointed end of the ‘tooth’ is supporting the material. Without good contact between the material and the slat, it becomes impossible to hold it steady, and the vibration is seen in the material along the cut line.”

Start today

Advances in software make it easier to keep up with machine maintenance. Programs such as MTConnect or OMAX’s IntelliVISOR run parallel with the controller’s software to provide a comprehensive report and alerts on the machine’s status, analytics that enable companies to maintain a lean and reliable inventory of spare parts and receive event notifications so operators can jump in immediately to ameliorate any potential production blockages.

The IntelliVISOR system monitoring package connects operation controls with machine maintenance and upkeep.

OMAX can help customers by reviewing their data. “We can see customer trends and be more predictive in both maintenance needs and projected consumable consumption for them,” Robinson notes. “For instance, if we see that an area is using a lot of a high-pressure parts, we can contact the customer about ways to make those parts last longer and look into the possibility of an underlying issue they may be having. We can also look at the history and determine when it might be necessary to rebuild a pump or other major component.”

A PM program can be launched at any time, even if machines are older and have been in use for years. Robinson advises waterjet users to take the first step by “either using the software or a notepad to begin recording daily pressure and RPM of the pump, then add a date and time for any maintenance and any parts you swap.” Collecting this data regularly will reveal consumption rates, giving users a heads-up on when to order filters, mixing tubes and abrasives.

Ultimately, the most crucial aspect of preventive maintenance is “scheduling the time to do it,” Robinson points out. “It is always cheaper to do the maintenance than it is to react” when something goes awry. “I suggest that companies actually schedule maintenance like it is a job they are going to cut. Almost everyone bids their jobs by time to cut on the waterjet. If you apply that to scheduling maintenance, then it won’t interrupt your production schedule and will pay off in machine up time.”