Plasma Cutting

       火花1.jpg The easiest and most convenient way to cut metal quickly and accurately is plasma arc cutting, which is as easy as cutting cheese.If you have never been exposed to plasma arc cutting and are not familiar with the operation method, it will be a little difficult for you, but as long as you are familiar with the plasma cutting machine in a short time, you can operate it.

      Compared with welding, plasma arc cutting is easier to use, and the machine setting method is also simpler for welding or oxygen/acetylene cutting.

      In this article, we will introduce you to the debugging method and basic knowledge of plasma cutting machine, so that you are familiar with plasma arc cutting and get started more quickly




How plasma is produced and how plasma cutting works?


      Plasma is a special form of matter in addition to solid, gas, and liquid. To put it simply and clearly, plasma is electrically conductive to make air reach extreme temperatures. That is, the air becomes an ionized gas. After this pressurized ionized air produces a plasma arc, you can use it to cut metal just like cutting cheese with a knife.

    There is an electrode inside the plasma cutting torch. The compressed air passes through the cutting torch and the electrode. After the charged electrode contacts the metal workpiece, a loop will be generated to initiate an arc, so the plasma gas arc is generated.

    At this time, the compressed gas conducts electricity and turns into plasma, which is ejected at a very high pressure through a very small nozzle. When the plasma contacts the metal with a very small area, it will generate a very high temperature to cut the metal. 






What materials can be cut by plasma?

Any metal that can conduct electricity




      Low carbon steel, stainless steel, aluminum, copper or any other non-ferrous metals. As long as it is conductive, you can cut it. As long as your plasma cutting machine has enough power and you can provide enough pressure air to handle the thickness you are using, you can perform smooth and beautiful cutting.

    You can use the plasma cutting machine in any dry place, such as cutting conductive materials in private garages, workshops, outdoors or construction sites.



Compared with Oxy-Fuel cutting,

what are the advantages of plasma cutting?


      First of all, this cutting process is only effective for steel and ferrous metals that undergo an oxidation process, because this method is to separate metals by burning or oxidation.

    In other words, materials such as aluminum or stainless steel cannot be oxygen cut. Plasma cutting is easier to learn and safer. You don't need to store oxygen or acetylene gas tanks. These gas tanks need to be stored in a specific environment, otherwise there is a danger of burning or explosion.

    However, storing the plasma cutting machine is very simple. You only need to cut off the power and place it in a dry and safe area. The use process is not as dangerous as fuel cutting.

    Plasma cutting requires gas under pressure, so you need to prepare an air compressor. Some plasma cutting machines have a small air compressor built-in so that you can cut low-thickness metals without an air compressor. But this is different from fuel cutting. You don't need to replenish the lost air, but the fuel needs to be replenished when the pressure is insufficient. Although the air compressor needs to be purchased, it can provide a steady stream of free air. But the price of fuel is high and requires continuous purchase, and it is not easy to move.




      Nothing is absolute. Although plasma cutting machines can be used immediately without preheating compared to fuel cutting, fuel cutting is a better choice if you need to cut very thick metals or if there is no power supply in your working environment. But for industrial practitioners or enthusiasts who often cut metal, plasma cutting machines are a better choice.



How to choose a suitable plasma cutting machine?


      There are some important factors to consider before choosing a plasma cutting machine. Not every plasma arc cutting machine meets your needs.

    On the one hand, you may buy a machine with great potential, but you will never give full play to the true strength of this machine. Although such a small load can extend its lifespan for this machine, most people are not willing to spend more money. What they need is to spend as little cost as possible to obtain a machine that can fully meet their work needs. machine.

    Next, I will tell you what parameters determine the performance and cost of a plasma cutting machine.




The maximum cut thickness and amperage


      The ampere power output of the plasma cutting machine greatly determines the clean cutting thickness and maximum cutting thickness of the machine

      The maximum clean cutting thickness represents the thickness you can cut without difficulty. The edge of the workpiece after cutting is very smooth and clean, and you don't even need to clean the edge of the workpiece after cutting.

      The maximum cut thickness represents the thickness at which the machine can separate the metal, but the cutting process may be slow and not so smooth. The edges after cutting will not be so beautiful and clean, you need to use an angle grinder or file to polish the metal edges.




      The amperage has a great influence on the cutting thickness of most plasma arcs, but the type of metal being cut also has a great influence.There are differences in the properties of metals, so some metals are more difficult to cut than others. For example, the output power of 55 amps is enough to cut 1/2'’ mild steel plate perfectly, but the cutting speed will be slower if the stainless steel plate of the same thickness is cut, but the cutting process will be very easy if the relatively soft aluminum plate is cut.



Duty cycle


      The percentage of the machine’s working time and rest time is called the duty cycle, which is usually calculated in the range of 10 minutes

    For example, if the duty cycle of the machine is 60%, then the machine can work for 6 minutes and rest for 4 minutes within ten minutes. If the working time is less than 6 minutes within 10 minutes, it is beneficial to extend the life of the machine.

    If you are cutting a piece of material with a very high thickness and close to the limit thickness that this machine can cut, even if the machine has not been overloaded, you need to pay attention to whether it is close to the rated working time of the machine, so as not to reduce the life of the machine.

   The rest time can allow the machine to cool down and prevent the high temperature generated by the machine load from damaging the machine circuit and reducing its life.




How to choose High-Frequency start or blowback plasma cutting machine?


      In general, if you use High Frequency pilot arc start plasma cutter, you should not use any electronic equipment on the job site. In theory, this type of machine will interfere with the surrounding electronic equipment, such as mobile phones, computers, CNC airports or other machines controlled by electronic chips. But only theoretically, this rarely happens during actual operation, but in order to comply with the operating safety instructions of the machine, you should not use electronic equipment in the attachment of the HF startup machine. 

    If you must use such sophisticated electronic equipment in your working range, the back-blowing technology pilot arc plasma start is a better choice. Such a plasma cutting machine starts the pilot arc through the special electrode movement in the cutting torch, thereby cutting off Circuit and produce an ionizing spark. But the only disadvantage is that such a machine is more expensive, and this choice will become a problem for many people.




Input voltage and portability


      Many plasma cutting machines on the market have 220V models and 110V/220V models.If your local voltage is 110V, you must choose a machine that supports 110V voltage, but there is one thing to note, the amperage calibrated by the machine is the rated amperage under 220V voltage, so you must ensure that the machine produces under 110V voltage The power can also meet your work needs.

    What is more important to the user of the machine is the weight and portability of the machine, if you are not using this machine in a fixed location in your personal workshop.

    If you carry this machine to and from different workplaces or residences, the machine is very portable and can perfectly adapt to the supply voltage on site, which is great! Both 110V and 220V can start to work.





      Compared with the welding machine, the plasma cutting machine does not need to prepare a lot of consumables, only some torch parts that are easily damaged by high temperature need to be replaced, such as nozzle tip, shield cup, gas ring, electrode and etc.So you need to pay attention to buying Is the cutting torch included with the plasma cutting machine or these accessories on the cutting torch that you bought separately are easy to buy?




How to get started with plasma cutting

      When you buy a plasma cutting machine, you can start to learn how to use it. This is not difficult, but at first you should use a thinner plate to cut some simpler shapes. You need to master some basic knowledge first and continue to master the cutting skills as you try.




Safety Precautions 

      Plasma cutting does not require very advanced welding technology like surface welding, and it looks very safe and simple. However, the output voltage of the plasma cutting machine can be up to 10 times that of the electric welding machine. Therefore, when operating the plasma cutting machine, you must wear suitable protective equipment, such as welding gloves, boots, aprons or split protective clothing. Bringing you very big damage, so these protective measures are necessary.

      The most important point is to prevent electric shock when operating the machine. Avoid using the plasma cutter when you are wet and sweaty and wearing insulated shoes and gloves. The most important thing is not to stand in water. When the plasma arc is started, you must wear suitable DIN shading-grade glasses or welding helmet to avoid electric light burns. If you burn your eyes, you may have 2~3 days of eyes tearing, unable to focus and photophobia, which may leave permanent damage .

      There are a lot of safety matters to pay attention to, but at present I can only tell you some basic safety knowledge, but the one that will never go wrong is "to follow the machine operation manual and standardize use from beginning to end, and follow the local work safety regulations.




Cutting skills

       The best way for inexperienced novices is to use a drag shield extension for the torch. In this way, you can put the cutting torch on the workpiece for operation, which will be more stable and precise.

      When starting the plasma arc, the angle of the cutting torch should be set to a 60 degree angle with the horizontal plane and a 30 degree angle with the vertical plane, and then rotate the cutting torch to the vertical position. Depending on the thickness of the metal, you need to find the right speed to drag the torch. You need to closely observe the cutting conditions of the metal and the angle at which the molten metal is pushed down the cutting line, which is about 20 degrees.

      If the cutting speed is too fast, the metal cannot be completely penetrated, and if it is too slow, residues will be left on the bottom of the metal, which may affect the appearance and cause metal deformation. You need some trial process to improve your skills, you can test on some scrap metal. From thin to thick, this is also the process of accumulating your experience.





      Hope you learned about basic plasma cutting in this article,

    Plasma cutting is very simple and easy to learn, you just need to prepare the machine and make a lot of attempts while following the safety regulations.

    If you have never operated a plasma cutting machine, you will not be able to cut a perfect straight line in a short time. This requires you to practice with a lot of scrap metal. But when you can cut a straight line without auxiliary tools, plasma cutting is not difficult for you.


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