Spring Cleaning

Plasma maintenance tips for optimal uptime and machine longevity regardless of the season

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Plasma cutting machines are known for cutting thick materials with precision and speed. Typically, a plasma cutter is the workhorse in any shop so any breakdown can affect overall productivity considerably. Even minor mechanical issues can cause premature wear and affect product quality. The bottom line is neglecting plasma cutting machine maintenance eventually results in decreased efficiency, costly repairs, premature machine failure and even safety issues.

A routine maintenance schedule can help prevent these unwanted results from occurring before they turn into a series of problems. Because plasma cutting machines are a complex system of various components working together, proper care and maintenance ensure that all the components interact with each other properly. Here are a few of the more important considerations for keeping plasma cutting machines in top working condition.

Inspecting the torch

It all starts with the torch. It’s common practice to clean the inside of the torch with a cotton swab to remove debris, but operators should also remove the torch parts to examine the inside of the torch, checking for any signs of damage. The next step is the torch leads.

ESAB’s Vision T6 is an intuitive next-generation controller for automated plasma and oxyfuel cutting machines.

“It’s important to inspect the torch leads on a regular basis,” says Steve Zlotnicki, global product manager, cutting systems, ESAB Welding & Cutting Products. “The torch leads, which consist of a set of hoses and cables that runs down to the top of the torch, are exposed to spatter and a lot of motion as the torch goes up and down, especially with a bevel head. The leads need to be inspected to make sure there’s no wear on the hoses and no leakage at either end.

“Those hoses carry the power to the plasma torch,” he adds. “With water-cooled torches, the cooling water hoses going to the torch have the power cable that carries power to the torch running inside the hose. The water is cooling the torch and is also cooling the power cable. If that internal cable has flexed too much, it starts to fray and that can lead to blocking the water flow. If you don’t have sufficient cooling of the torch anymore, obviously that’s a problem. That’s something that should be inspected regularly, as well.”

Overall, the cooling system, coolant levels, filters and pumps should be inspected periodically for water-cooled plasma cutting systems. Any filters or components should be cleaned or replaced as necessary and appropriate coolant levels need to be maintained to prevent overheating.

Checking rails and racks

Next up, other components such as the rails, gears and racks need to be inspected and cleaned.

“In most machines these days, the motion systems are pretty reliable – the motors, gearboxes, amplifiers and so on don’t have any issues,” Zlotnicki says. “It’s the mechanical aspects of the motion system like the linear rails that need to be cleaned. It’s usually just a matter of wiping off dirt just make sure it’s not accumulating.”

These components also need to be lubricated on occasion. Typically, it is the number of up and down motions that specifies how often to lubricate. The machine’s documentation or manufacturer recommendations will supply information on the appropriate lubricant and the intervals.

“If they’re not properly cared for and they dry up,” Zlotnicki notes, “you will start to tear up the linear bearings and that eventually leads to the machine not being able to move at all or very inaccurately or maybe the bearing blocks break and drop all the bearings on the table and then you’re really out of business.”

Also, some rails have scrapers that scrape some of the dirt away. The scrapers need to be cleaned and inspected for wear because they will eventually wear out and need to be replaced.

“Another thing to be aware of with the motion systems is the rack and pinions,” Zlotnicki says. “Those can wear out pretty quickly if the mechanical system that engages the pinion is putting too much pressure on the pinion and pushes it into the rack. The two pieces are constantly meshing and they will eventually wear out. So the rack and pinions should be inspected on a semi-annual basis for wear.”

Plasma gas quality

The plasma gas supply is critical for plasma cutting so addressing any issues quickly is key to maintaining consistent gas flow and cut quality.

“Any fuel gas system is a significant safety issue and so it needs to be maintained, leak tested and pressure tested on a regular basis,” Zlotnicki says. “Maintenance personnel or service engineers need to occasionally do leak checks on the entire system, from the supply cylinders or bulk tanks or whatever they’re using through to the regulators. They should check that the regulators are functioning properly and putting out the right pressure and that there are no leaks. Also, check that the gauges are indicating properly.

The Combirex Pro automated cutting system offers a large gantry design in a compact package and delivers the cutting performance users expect from ESAB.

“Leak testing procedures can involve going around with a soapy solution and checking all the fittings, but also shutting down everything once it’s fully pressurized and leaving it overnight or for a certain number of hours,” he says. “If it has lost pressure, then you know you have a significant leak somewhere. A properly functioning system should hold pressure going on four hours easily.”

Safety factors

Beyond performance and quality, following a maintenance routine leads to a safer working environment. Regular inspections and maintenance procedures help identify and address potential safety hazards.

Loose or faulty electrical connections can result in safety hazards as well as poor machine performance. All electrical connections, including power cables, connectors and ground connections, should be checked.

“Typically, electrical cabinets have interlocked switches on the doors and, sometimes, they will get bypassed or stop functioning, so they should be checked and maintained properly,” Zlotnicki says. “Also, with a plasma cutting system, obviously you have fairly large electrical cables carrying power to the torch. They should be inspected for damage because if they short out that can cause a safety hazard.”

He adds that the entire safety grounding system on both the gantry cutting machine and the cutting table have to be properly grounded. Otherwise, there’s a potential safety hazard of having an electrically charged machine that if the operator then touches and, if he bridges the ground, he can get severely shocked.

Surprisingly, Zlotnicki says that safety wise, the plasma cutting table is probably responsible for the most injuries.

“We’ve heard from customers that say the single biggest cost in their entire operation is safety accidents related to people walking on the cutting table,” he says. “When loading and unloading plate on the table, it’s very easy to fall between the slats and become injured. If it’s a downdraft table, you can fall even farther before you land on something. On larger machines especially, the center of the table may be 10 ft. or 15 ft. away from the side of the table so if a part falls, they have to walk on the table to get it.”

There are other safer methods to retrieve parts, but most shops can’t afford an expensive conveyor table or magnetic pickup system.

ESAB’s DMX plasma beveler, however, has a crash protection device that does not break away and is easily reset by the operator from the control panel. This means they should never have to climb up on the table and touch the torch in order to reset a crash.

Professional help

Part of a maintenance routine for plasma cutting systems is regular calibration, which typically requires professional servicing. Things related to the accuracy of the motion system, like aligning rails, are best left to the professionals with the right tools and the right know-how.

“It’s not common, but rail alignment issues can happen,” Zlotnicki says. “We had one customer install a machine on a brand-new concrete floor. Within six months, the rails were almost an inch out of being straight because the floor had settled. A more common occurrence is the customer bumping into the rails with the forklift or other machine. If that happens, they need to be checked for straightness and alignment.”

DMX is a reliable plasma bevel system thanks to ESAB’s Direct Multi-Axis motion system, which uses fewer parts for higher reliability and reduced maintenance.

As for the torches, “most straight cutting torches aren’t an issue, but with a bevel torch, the torch rotates and tilts so those systems require a pretty significant alignment procedure sometimes,” he says. “That is way more than an operator would typically do.”

Some modern plasma bevel heads, like the DMX, have an alignment device that measures the motion of the torch, calculates the offsets and adds those values into the machine’s CNC.

“That’s something an operator can do in about 15 min. on the DMX torch,” Zlotnicki says. “They can check the alignment and do the alignment procedure whereas older systems often require the maintenance person to set up a dial indicator and do a lot of adjustments in various offset screws to make sure things are centered for rotation and tilt.”

Routine maintenance of plasma cutting machines minimize the chances of downtime and ensures the safety of operators. Understandably, a well-maintained plasma cutter operates more efficiently and minimizes operating costs.

Looking toward the future, ESAB is working on the development of new maintenance software systems that will be integrated into its new Vision T6 controller. It will allow customers to build an entire maintenance system into a user interface and CNC that can then be tracked offline using the Cut Cloud system that can also recommend maintenance to perform.

“Everybody understands the benefits of collecting data these days and that’s exactly what our Cut Cloud system is all about,”

ESAB Welding & Cutting Products

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