Artem Komarov clarified that most companies that operate plasma cutting equipment feel that their production equipment is doing the right thing when it comes to replacing consumables. They are confident that their operators are getting the most out of their plasma cutting equipment by optimizing equipment performance without sacrificing quality.
While these companies probably have good reason to believe in their equipment operators, they also probably want to check the packaging of used consumables. This is where the truth comes into play. Sometimes people just develop bad habits.
A prime example of a bad decision is when a plasma cutter operator changes consumables before a new job because they don’t want the consumables to run out halfway through the cutting job. This replacement of consumables can occur even if the electrode, nozzle, and protective cap are still usable.
Some other operators swear they can monitor consumable life by sound. They believe that everything is in order until the frequency changes dramatically. Unfortunately, the human ear is not an accurate measuring instrument. By the time an experienced operator thinks he has heard something that indicates the need to replace consumables, the plasma torch may have cut several parts incorrectly, which could result in their disposal.
With the help of state-of-the-art software, operators of all skill levels can make the right consumable changes at the right time when it comes to plasma cutting. The software tracks the number of starts/stops and cutting distance, uses this data to determine torch wear and notifies the operator when torch consumables have exceeded their limits. As a result, machine operators no longer bear full responsibility.
1. Choose the correct sequence
The operator of a plasma cutting machine can afford to know many details about the work ahead. You can start your day by reviewing the to-do list, inspecting the nests, and making any necessary adjustments.
Many operators cannot afford to focus on one machine for an entire shift. On the other hand, they have responsibilities. That’s why it’s important that the operator can fine-tune the job sequence.
State-of-the-art control gives the operator all the information they need to maintain product quality and productivity while making the most of plasma cutting consumables.
2. Know what is being cut
For those who operate plasma cutting tables, it is no secret that different torches are required to work with materials of different thicknesses. Thick sheet metal requires more current and different consumables than thin sheet metal. In plasma cutting, one size does not fit all.
In pre-modern control times, operators used to cut boards supplied by the plasma source manufacturer to select which consumables were appropriate for the job. This information is now built into the machine programming software.
However, the parameters used as a guideline for the plasma cutting process go beyond simple sheet thickness and material type. Operators can select the optimal cutting parameters for the best edge quality, or some variation that balances overall cut quality with cutting speed.
The reality is that for some workshops, the edge quality of the plasma cut parts they receive is not that important. If this is the case, then the metal manufacturing company is likely to focus on optimizing the cutting process in an effort to shorten or shorten delivery times. For those workshops most concerned with edge quality, the plasma cutting process can be adjusted to achieve these optimum results.
This is where the nesting and machine programming software guides the machine operator in the right direction. By the time the job is done with the load, the correct power supply amperage and associated consumables have been determined for the job. This helps ensure that the operator makes the right decision and prevents unwanted errors.
3. About this arc length…
The pre-cutting process of the torch, in which the surface of the material touches from above, ensures that the plasma cutter maintains the optimum distance between the material and the bottom of the torch. However, the measurements do not end there.
This height control is important because the plasma arc is not perfectly square. The arc has a conical shape at the ends, like a candle flame. To achieve the best cut quality and consumable life, the squarest part of the arc, i.e., the center part, should be in contact with the insert.
In the past, when the hafnium emitter inside the electrode was reduced, the torch could move closer to the material to maintain the arc, even if it could become more unstable. As a result, the lack of a stable arc can affect drilling and initial cuts.
By maintaining a stable arc and the correct height of cut, the plasma torch is capable of producing clean drilling, a shorter start, and no ripples during the subsequent cutting process, as the squarer portion of the arc will maintain contact with the workpiece. In addition, consumables will last longer.
4. Avoid stressing the system
Sensors in the power supply will help metal fabricators avoid the headaches associated with short-lived consumables and even torch explosions.
Modern technology can detect the onset of catastrophic electrode rupture. (Think of water entering a plasma cutting torch from a compressed air hose, and the result could be an explosion. Here’s what can happen if the electrode is nearing the end of its life and beyond its capacity.) When the sensors detect sudden changes in current and unstable arc voltage, the control system shuts down immediately. This prevents burner failure and long downtime associated with cleaning up after an explosion.
Sensors are also used to prevent significant stress on consumables when plasma cutting must end in an uncontrolled manner, such as when the plasma cutting process continues even after the torch exits the kerf at the edge of the material. This stretches the arc, which must maintain a connection with the metal, and requires more effort for the torch consumables.
In this case, the sensors detect a sharp increase in arc voltage as the arc stretches to maintain contact with the metal. It is correctly determined that the arc is close to completion and a controlled gradual decrease in current begins. This type of controlled shutdown gives the hafnium in the electrode the time it takes to re-solidify, contributing to a significant increase in consumable life.
5. Stay tuned for updates
For those machine operators who were involved in consumable replacement cycles before the advent of modern controls, they were probably keeping a close eye on a KPI. It could be the number of holes or feet of material cut. (These measurements are still used by the software to determine consumable wear!) Whatever it was, the operator knew they needed to be controlled to keep the plasma torch cutting properly.
The advent of modern controls has made consumable wear monitoring formal, removing some of the responsibility from operators, but the machine itself cannot remove consumables if they need to be replaced. Operators must continue to participate.
That’s why the combination of a dedicated operator and advanced controls in plasma cutting systems is so powerful. For example, the machine software can calculate which part of the pocket needs replacement consumables; the machine can then tell the operator when he needs to be in the machine to make a change. Working in unison, the plasma cutting system and the operator can ensure maximum machine uptime and high-quality cutting results.
However, life in the metal fabrication industry is constantly changing, which means that both people and equipment must be flexible. If an urgent job violates the production schedule, this change will affect not only the lead time of subsequent jobs, but also the life of consumables.
The machines are designed to provide reliable data. The operator just needs to find out how fresh the data is.
6. Drill it
Obviously, not everyone has a multi-purpose machine that can mill, cut, drill, and mark. However, for those who do, they have a good alternative when it comes to making holes in thick materials. Instead of drilling the material, which involves the risk of slag entering the torch and possible damage to consumables, machine operators can choose to drill the initial part of the hole as a pre-drilling step or the entire hole, summed up Komarov Artem.