Plasma cutters are versatile tools used in a variety of industries. However, like any other tool, there are common problems associated with them. These include issues with the power supply, torch, and consumables.
Additionally, operators may experience problems with the accuracy of the cut and with the overall functionality of the machine. Knowing how to troubleshoot these issues can help operators quickly and effectively identify and resolve any problems that may arise.
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1. Arc Blow
Arc blow is a phenomenon in which the arc of an electric arc welding (EAW) machine is deflected due to the magnetic fields generated by the workpiece or the surrounding environment. Arc blow can cause the weld to be misaligned, or even cause the arc to be extinguished, resulting in incomplete welds.
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In plasma cutters, arc blow occurs when the arc is deflected by the surrounding air, causing the arc to move away from the intended cutting path.
For example, if the arc is cutting a straight line and the air is blowing, the arc may be deflected and the resulting cut may be curved or jagged.
How to prevent Arc Blow?
Reduce Amperage: By reducing the amperage of the plasma cutter, the arc force will be decreased which will reduce the risk of arc blow. As a general guideline, the amperage should be reduced by 10-15% for thick metal, 20-25% for thin metal, and 40-50% for aluminum.
Increase the Electrode Standoff: Increasing the electrode standoff will reduce the arc force and reduce the risk of arc blow. As a general guideline, the electrode standoff should be increased by 10-15% for thick metal, 15-20% for thin metal, and 25-30% for aluminum.
Increase the Shield Gas Flow: Increasing the shield gas flow will reduce the risk of arc blow by creating a stronger shield between the electrode and the workpiece. As a general guideline, the shield gas flow should be increased by 10-15% for thick metal, 15-20% for thin metal, and 25-30% for aluminum.
Use a Backing Plate: By using a backing plate, the plasma arc will be forced away from the workpiece, reducing the risk of arc blow.
Use a Drag Shield: By using a drag shield, the plasma arc will be forced away from the workpiece, reducing the risk of arc blow.
Use a Water Table: By using a water table, the plasma arc will be forced away from the workpiece, reducing the risk of arc blow.
Use a High-Frequency Arc Starting Device: By using a high-frequency arc starting device, the arc force will be reduced, reducing the risk of arc blow.
Use a Magnetic Arc Control Device: By using a magnetic arc control device, the arc force will be reduced, reducing the risk of arc blow.
2. Poor Cut Quality
Poor cut quality in plasma cutters can be attributed to a few factors. Examples include improper arc length, incorrect torch height, incorrect standoff distance, and improper travel speed.
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For example, if the torch height is not set properly, the tip of the torch will be too close or too far away from the workpiece. This will create a wide, ragged cut that is not straight.
Similarly, if the standoff distance is not set correctly, the arc will be too focused or too wide, leading to poor cut quality. Finally, if the travel speed is too slow, the torch will not be able to cut at an optimal speed, leading to an uneven cut.
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How to prevent poor cut quality?
There are several steps that can be taken to prevent poor cut quality when using a plasma cutter.
First, it is important to make sure the plasma cutter is properly set up before cutting. This includes ensuring that the torch and nozzle are clean, that the cutting tip is in good condition, and that the air pressure is set according to the manufacturer‘s specifications.
For example, if the manufacturer‘s specifications call for 60 psi (pounds per square inch) of air pressure, make sure the air pressure is set to 60 psi.
Second, it is important to use the right cutting parameters for the material being cut. This includes selecting the correct amperage and cutting speed, as well as setting the piercing height and piercing delay.
For example, if the material being cut is 1/8“ thick aluminum, a cutting speed of 40 inches per minute and an amperage of 40 amps may be appropriate.
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Third, it is important to make sure the material being cut is securely clamped in place. This will ensure that the material does not move during the cutting process, which can lead to poor cut quality. It is also important to make sure the material is free of debris, as debris can interfere with the cutting process.
Finally, it is important to make sure the cutting path is smooth and even. This will ensure the cutting torch is able to make a clean, consistent cut. It is also important to use the right technique when using the plasma cutter. F
or example, when cutting curves or circles, it is important to move the torch in a steady, circular motion. By following these steps, poor cut quality can be prevented when using a plasma cutter. Read our guide on Plasma cutting tips for better results.
3. Low-Duty Cycle
A low duty cycle in a plasma cutter is the result of the design of the machine. The plasma cutter has a high–power electrical component that is used to create a plasma arc, which is then used to cut through materials. This component creates a lot of heat and needs to cool down periodically.
The duty cycle of the plasma cutter is determined by the amount of time that the machine can be in operation before it needs to cool down. Generally, a lower duty cycle indicates that the plasma cutter will need to cool down more frequently after less time of operation.
This is because the higher the power of the machine, the faster it will heat up, and the sooner it will need to cool down in order to maintain a safe operating temperature. A low-duty cycle is therefore necessary to prevent the machine from overheating and causing damage.
These will help in preventing poor duty cycle
A low-duty cycle on a plasma cutter is an indication that the machine is being pushed beyond its capacity. This can result in poor cutting performance, shorter consumable life, and even machine damage. To prevent a plasma cutter from experiencing a low duty cycle, there are a techniques that can be employed.
First, the amperage of the plasma cutter should be set to the correct level for the material being cut. The thicker the material, the higher the amperage should be set. If the amperage is too low, the plasma cutter will be working too hard and will result in a lower duty cycle.
Second, the air pressure of the plasma cutter should be set to the correct pressure for the material being cut. Too low of an air pressure can cause the plasma cutter to suffer from an inferior duty cycle. The proper air pressure will be listed in the manual of the plasma cutter.
Third, the cutting speed of the plasma cutter should be kept in check. The faster the cutting speed, the more strain it puts on the machine. Cutting speeds of more than 20 inches per minute (IPM) should be avoided.
Finally, proper maintenance of the plasma cutter is key. The consumables should be changed regularly, and the machine should be serviced at least once a year. This will help ensure that the plasma cutter is running optimally and will not suffer from a low duty cycle.
4. Low-Cut Speed
Low cut speed in plasma cutters can occur for a variety of reasons. The most common cause is a buildup of material in the nozzle of the plasma cutter. This can be caused by improper use of the plasma cutter, such as using a different material than what the cutter is designed for, or by not keeping the nozzle clean.
Poor cut speed can also be caused by the incorrect setting of the air pressure or gas flow rate, or by a failure of the power supply or an internal component of the plasma cutter.
Additionally, inferior cut speed can be caused by a lack of proper maintenance of the plasma cutter. Examples of proper maintenance include regularly changing the consumables such as the torch head, nozzle, electrode, and swirl ring, as well as ensuring the plasma cutter is adequately lubricated and the air and gas filters are clean.
- How will you prevent poor cut speed?
- Ensure your cutter is running on the correct amperage for your material thickness. A plasma cutter should have an amperage between 20 and 60 amps when cutting 1/8 inch material. If the amperage is too low, it will result in a slow cut speed and lower quality of the cut.
- Make sure the nozzle and electrode are correctly installed and in good condition. A damaged nozzle or electrode can create an unstable arc, resulting in a slow cut.
- Check to make sure the air pressure is correct. Too much air pressure can cause a decrease in the cut speed and too little air pressure can cause the arc to be unstable. The optimal air pressure for a plasma cutter is around 60 PSI.
- Clean the nozzle and electrode regularly to remove any dirt or debris that may be blocking the arc. A blocked arc will cause the cutter to run at a slower speed.
- Make sure the consumables are rated for your material thickness. Using consumables that are not rated for your material thickness can cause a decrease in cut speed and quality.
- Make sure the material you are cutting is free from dirt, rust, or any other debris that would affect the cutting performance.
- If the plasma cutter is having trouble starting, check the pilot arc gap settings. The optimal settings are between 0.5 and 1.5 mm. If the gap is too small, the cutter will run at a slower speed.
5. Poor Edge Quality
Poor edge quality in plasma cutting can be caused by a variety of factors, including incorrect setup of the equipment, improper speed and amperage settings, incorrect or worn consumables, and dirty air.
For instance, incorrect speed and amperage settings can cause the plasma arc to move too quickly or too slowly, resulting in a rough edge or poor cut quality. Similarly, incorrect or worn consumables can also cause poor edge quality due to the plasma arc not being able to maintain the proper temperature and pressure. This can cause the arc to wander, creating a wider kerf and a rough edge.
Finally, dirty air can also cause poor edge quality, as debris from the air can contaminate the plasma arc, causing it to move erratically. This can result in a wider, rougher kerf and poor edge quality.
Prevent Poor Edge Quality
- Maintain a consistent cutting speed. The slower the speed, the less heat produced, and the better the edge quality.
- Use the right nozzle size. A smaller nozzle size will produce a narrower cut and reduce the heat produced, resulting in a better edge quality.
- Use proper gas pressure. Too much pressure can cause excess heat and poor edge quality, while too little pressure can cause the cut to be too wide and produce a poor-quality edge. The proper gas pressure for plasma cutting depends on the plasma cutter and the thickness of the material being cut. Generally, the pressure should be between 15-25 PSI (pounds per square inch).
Use the correct air pressure. Too much air pressure can create a swirling effect that will cause the edges to be rough and uneven, while too little air pressure can cause the edges to be too wide. Follow our air pressure guide for more.
- Use a high–quality plasma cutting torch. A higher quality torch will produce a better edge quality, as it will have a more consistent arc and better heat control.
- Use the correct consumables. Consumables such as the nozzle, shield, and electrode should be replaced regularly to ensure a consistent edge quality.
- Use a proper piercing height. A piercing height that is too low can cause poor edge quality due to excessive heat, while a piercing height that is too high can cause the edges to be too wide.
- Use a good cutting table. A good cutting table will ensure that the metal is supported properly, which will help to reduce heat and produce a better edge quality.
6. Slag Build–up
Slag buildup in plasma cutting is caused by molten particles of the material being cut sticking to the nozzle or the cut surface. This can cause a variety of problems such as reduced cutting speed, clogged holes, and poor cutting quality.
Examples of slag buildup include the deposition of a layer of molten material on the cut surface, the accumulation of molten material around the nozzle, and the accumulation of molten material inside the hole being cut. Slag buildup can also cause the nozzle to overheat, resulting in decreased cutting performance.
To get rid of this, focus on the followings:
- Use a high–quality consumable: High–quality consumables can help prevent slag build up in a plasma cutter. Make sure to use quality parts that are designed for your machine and the material you are cutting.
- Ensure the correct standoff distance: The distance between the torch tip and the material should be 1/8” (3.2 mm) for most materials. This helps ensure that the plasma arc is hot and powerful enough to vaporize the metal. If the distance is too great, the arc will be weak and the slag build up will be greater.
- Use a higher air pressure: Increasing the air pressure in the torch can help prevent slag build up. A higher air pressure helps to create a more powerful arc which can help to vaporize the material more efficiently.
- Keep the nozzle clean: Residue, dirt, and debris can build up over time on the nozzle and affect the performance of the plasma cutter. Make sure to clean the nozzle regularly to prevent slag.
- Use a drag shield: Dragging a shield between the torch tip and the material can help to reduce slag build up. The shield helps to provide a consistent standoff distance and helps to keep the material from sticking to the torch tip.
- Use a pre–heater: Pre–heating the material before cutting can help to reduce slag. Preheating helps the material to expand, allowing the plasma arc to penetrate more effectively.
7. Power Interruption
Power interruption in plasma cutting can happen for a variety of reasons. One of the most common reasons is an electrical short in the plasma cutting torch. If there is an electrical short, the current flowing through the torch will be disrupted and the arc will be extinguished. This will cause the plasma arc to lose power and stop cutting.
Another common cause of power interruption is a water or air leak in the plasma torch. If water or air enters the plasma torch, it can cause the torch to lose power and stop cutting. This is because the water or air will interfere with the flow of electricity through the torch.
Finally, power interruption can be caused by a dirty or clogged plasma torch. If the plasma torch is dirty, it can cause the torch to become clogged and lose power. This will cause the arc to be extinguished and the plasma arc to stop cutting. In all of these cases, the best action to take is to clean the plasma torch and check for any electrical shorts or water/air leaks. This will help to ensure that the torch is functioning properly and the plasma arc is able to cut properly.
Prevent Power Interruption
- Ensure that the plasma cutter is connected to an uninterrupted power supply (UPS). A UPS is a battery–powered device that will provide power to the plasma cutter during a power outage, allowing the user to safely stop the cutter and disconnect it from the power source.
- Ensure that the plasma cutter is connected to a reliable power source. This can be done by using heavy–duty extension cords and power strips that are rated for the amount of power the plasma cutter requires.
- Install a surge protector to protect the plasma cutter from power surges. This will help prevent damage to the cutter and related components.
- Make sure that all connections between the plasma cutter and any other device are properly wired and grounded. This will help protect the cutter from power fluctuations.
- Always use an air compressor with the plasma cutter. This will ensure that the plasma cutter has enough air to run at its full potential and reduce the chance of a power interruption.
- Inspect the plasma cutter and any related components regularly. This will help identify any potential problems before they become an issue.
- Make sure that the plasma cutter is placed in an area that is free from debris and other hazards. This will help reduce the chances of a power interruption caused by something coming into contact with the cutter.
8. Contamination
Contamination in plasma cutting can occur due to several factors. Firstly, poor maintenance of the plasma cutting equipment can lead to deposits of dirt, dust, and other contaminates building up on the components of the system. This can result in the contamination of the plasma arc and the cutting surface, leading to imprecise cuts and an overall reduction in the quality of the finished product.
Another common source of contamination can be due to the choice of material. If a material is not suited to plasma cutting, particles of the material can be flung away from the cutting area and contaminate the surrounding area. These particles can then be deposited onto other materials and cause contamination issues.
Finally, contamination can occur due to the environment in which the plasma cutting is taking place. If the environment is contaminated with dirt, dust, or fumes, these can be drawn into the plasma arc and contaminate the cutting area. This can lead to inaccurate cuts and an overall reduction in product quality.
How to prevent contamination?
- Wear Personal Protective Equipment (PPE): Wear safety glasses, gloves, a face shield, and a welding helmet when operating the plasma cutter. Appropriate PPE can help protect your hands, eyes, and face from the high temperatures and electrical hazards associated with operating the plasma cutter.
- Keep the Work Area Clean: Make sure the workspace is free of clutter, debris, flammable materials, and other combustible materials. This will reduce the risk of sparks and flames that can cause fires and other hazards.
- Proper Ventilation: Proper ventilation is essential to reduce the risk of exposure to hazardous fumes, gases, and other airborne contaminants. Ensure that the ventilation system is working properly and that the exhaust is routed away from the operator.
- Ground the Workpiece: Always make sure the workpiece is properly grounded before operating the plasma cutter. This will reduce the risk of electric shock and other hazards.
- Pre–Check the Equipment: Before operating the plasma cutter, visually inspect all components and check for proper operation. Check the power supply and water supply, if applicable, to make sure they are functioning properly.
- Keep the Cutting Torch Clean: Make sure the cutting torch is clean and free of dirt, dust, and debris. This will reduce the risk of clogs, misfires, and other problems.
- Read and Follow the Manufacturer’s Instructions: Read and follow the manufacturer’s instructions for proper operation of the plasma cutter. This will help ensure safe and effective operation.
9. Excessive Consumable Wear
Excessive consumable wear in plasma cutting is typically caused by one of two things: improper cutting technique or an incorrect consumable selection for the application.
Improper cutting technique is the most common cause of excessive consumable wear. Some common mistakes include cutting with too high an amperage, traveling too quickly, or not allowing the arc to pierce the material properly.
These mistakes can lead to increased heat buildup in the nozzle, resulting in rapid wear of the nozzle and other consumables. An incorrect consumable selection is also a common cause of excessive wear.
Using the wrong nozzle or electrode size, or a consumable with a lower quality rating than is suitable for the application, can lead to accelerated wear.
Additionally, using a consumable with the wrong material composition or a geometry that is not suited to the application can also cause excessive wear.
In order to avoid excessive wear, it is important to select the correct consumables for the application and use proper cutting techniques. Consulting with an experienced plasma cutting supplier to determine the best consumable selection and cutting techniques can help to avoid excessive consumable wear and ensure the highest quality results.
10. Poor Electrical Connections
Poor electrical connections in plasma cutting can occur when the torch and work cable connections are not tight or secure. When the electrical connections are loose, the electrical flow is interrupted, resulting in poor cutting performance and possible damage to the plasma cutting system.
To solve this problem, the connections must be checked and tightened. For example, the torch should be inspected to ensure that the connections are clean and secure. O–rings should be replaced as needed and all connections should be tightened with a wrench. Additionally, the work cable connection should be checked and tightened to ensure a secure connection between the torch and the power source.
Conclusion
In conclusion, plasma cutting is a great process to use when cutting metal, but it’s important to be aware of the common problems that can occur. By understanding the common problems with plasma cutting, as well as taking the necessary steps to prevent them, you can ensure that your project is completed safely and efficiently. With proper preparation and maintenance, you can ensure that your plasma cutting job will be successful.
