Posts Tagged ‘Plasma Cutters’

Polarity: When should it be reversed? Part 1

Monday, October 10th, 2011

Any one that has been around welding for a short period of time knows a little about the term “Polarity”.But quite a few new comers find the correct use of polarity a confusing issue, though it need not be.  A lot has been written on the internet about polarity, and this blog will undoubtedly add to that information. But, hopefully it’ll be easier to understand than some of the other ponderous articles written about it.

Polarity ?

Polarity ?

Polarity is simply a term to describe the whether the electrode is a cathode or anode.  Quite simply it refers to whether the electrode is emitting (negative polarity) or receiving electrons (positive polarity). These terms are related to DC welders only. Welders that output AC current have no need to refer to polarity.  So if you are welding with an old AC buzz box welder, polarity is of no consequence to you.  But if you are welding with new inverter welder, or even an old DC transformer welder, it is.  Sometimes you may see the terms DCEP or DCEN.  These refer to Direct Current, Electrode Positive, or Direct Current Electrode Negative. Polarity is always marked  on a DC welder  and will usually bear a simple negative (-) or positive (+) sign.   Whenever a polarity change is required, the electrode (sometimes referred to as a torch) should be inserted into the side with the marking that corresponds to the polarity recommended.

Simple huh?  Well, not that simple.  A lot of old texts and “old school” welders will often refer to the terms of “Straight Polarity” and “Reverse Polarity”. Straight polarity refers to negative polarity. Reverse polarity refers to positive polarity. While that may seem to make sense, if you think about electrons always flowing from negative to positive poles, it is confusing when it is applied to several different welding processes such as stick and MIG welding.

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The Plasma Cutting Process : PAC

Monday, October 3rd, 2011

Plasma Arc Cutting (PAC) is probably one of the single most coveted items in a well equipped shop. Almost all commercial shops are equipped with Oxy-fuel for cutting. In fact, I can’t think of any reason a commercial shop would not have a Oxy-Acetylene rig. But up until the last 10 years, many established shops did not have a plasma cutter. A few still don’t. As technology has improved, and prices have gone down and availability has gone up, more and more shops and even hobbyists are making the plasma plunge.

What makes plasma so desirable? It would be difficult to pinpoint any one feature. Plasma cutters are capable of making extremely clean and accurate in any metal, something that cannot be done with Oxy-Acetylene torches. Speed is another factor, with plasma having an edge over Oxy-Acetylene when trying to achieve similar cut quality. Low temperature input also reduces metal distortion while cutting. A major deciding factor for most is the relatively low skill required to operate one. Almost anyone can turn out competent cuts within a short amount of time with just a little practice. Most plasma cutters are easily taken right to the site to work. There’s no dangerous gases to work with. There’s no large bottles to carry around or fill. Most plasma cutters use air compressors which are already found in many shops. Air hoses can be run quite a long ways to the unit giving a lot more portability around the shop with a reduced foot print. Some plasma cutters even have the compressor built in and will operate on 120 volts, allowing it to be used almost anywhere in or out of the shop.

There are some drawbacks to plasma though. While plasma may give Oxy-Fuel a run for its money on performance cutting, it cannot be used in situations where it is necessary to heat metal. Nor can it weld or braze. Plasma can only be used to cut or gouge any metal. Oxy/Acetyelene will weld, cut, braze and heat…though it is limited mostly to steel on cutting. The initial purchase of a plasma system is much higher as well, especially if an air compressor is needed. Consumables should always be kept handy as this is a wear item that is constantly needed. Also, electricity is needed and may be a limiting factor in remote locations. Oxy-Fuel rigs have no such requirements. Torch tips for Oxy-Fuel last much longer for sure and rarely need replacing.

Carefully evaluate your needs and capabilities before purchasing a plasma cutter. It is not a good fit for everyone. It is not a substitute for a good Oxy-Fuel rig because of its limitations. But if you do feel it’s a good fit for you, Everlast offers a full range of plasma cutters from 50 to 100 amps, with cutting capacities up to nearly 2 inches. Well priced from $700 dollars, there’s probably a unit that will fit your needs.

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Need for Water Shroud in Plasma Cutters

Tuesday, May 10th, 2011

The plasma can be made to function with a water shroud or in an alternative case by submerging the work piece for some 50 to 75mm below the surface of the water. Either ways, water is used to keep the condition or temperature of the process under control.

Unlike in the usual plasma cutting methods, we can find that the water takes the role of being the barriers. The advantage of Water Shroud in plasma cutters is that it reduces fumes, decreases noise levels to a great extent and improves the life of the nozzle.

In a usual method the noise levels were noted to be at high current levels of 115dB. But for the conventional plasma cutting machine we can note that the water shroud played a vital role in reducing the noise level to about 96dB.

Seeing that the water shroud will not add to the quantity of constriction, we can note that the squareness of the cut edge as well as the cutting speed is improved to a great extent.

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Water injection in the Plasma Arc Cutting Process

Friday, May 6th, 2011

As we all know water is used as a coolant in many industrial methods that involves high temperature for the process. Same ways water injection in the plasma arc cutting process also has a specific use. Water is injected through the injector into the plasma arc.

The plasma arc is generally got when Nitrogen is used as plasma gas in most of the plasma cutting machines. When the water is introduced to the plasma arc it induces a high degree of constriction. We can note that the temperature shoots up considerably to 30,000°C and above in this particular process.

If you compare the above process advantages with conventional plasma you can notice that there is a substantial Improvement in cut quality as well as squareness of cut. Apart from the improvement in cut quality we can also find an increase in cutting speed, less noticeable risk of double arching as well as decrease in nozzle erosion.

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Powers Source of the Plasma Arc Cutting Process

Thursday, May 5th, 2011

Plasma arc cutting process is one of the most efficient methods available to ensure sharp and perfect cut on any metal sheet of any desired thickness. The power required for such perfect cut is high and is attained by regulating that amount of plasma flow which is required for each metal sheet.

The power source for the Plasma Arc Cutting Process should contain a relaxed characteristic as well as a high voltage. Even though the operating voltage for sustaining the plasma used for the cutting process is on average 50 to 60V, the open circuit voltage that is required to kick off the arc is noted to be up to 400V DC.

On start, the first arc is created inside the cavity of the torch which is between the electrodes along with the nozzle.  When the cutting is to be performed the arc should be transferred to the work piece and is hence called as the transferred arc mode.

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Multi Purpose units for Garage shops

Monday, March 7th, 2011

Today, when you open a garage you would like to have versatile equipment ready for your tasks. This is because the multipurpose units can be used for different types of welding or cutting process that will help to complete projects faster. Normally to set up a metal working workshop or a welding workshop you have to purchase different equipment for different purposes.

However if you purchase a multipurpose unit you can make sure that the power for all your welding and plasma cutting needs are done out of a single unit. This will ensure that you not only save space but also the cost of equipment are drastically reduced. The multipurpose units are perfect for those quick automobile repairs or the tedious long work on the pipes that are made simple and easy with the right equipment.

Also these units often come with a power saving option that will reduce the amount of power that is consumed by such equipment without sacrificing on the output. Therefore if you need to get across the finish line or need to run to a broken pipeline, then make use of the portability of such a machine to make on spot repairs that will help to save time and money.

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Gas Plasma Cutting Machine

Monday, February 28th, 2011

When it comes to manufacturing and producing goods, the processes invariably involves cutting and joining of metals such as steel, aluminium, stainless steel, titanium, copper, nickel and other alloys. Plasma Cutting Machines are quite reputed and well established, they happen to be the most reliable machines when it comes to cutting of metals. These metals mentioned above have a lot of applications and machines or goods created based upon them are quite good and best thanks to the sturdy nature of the metals being used. In order to manufacture such goods or machinery, the metals need to be cut into several shapes and sizes and has to be highly precise as per the requirements. That’s where plasma cutting machines come into the picture. They are the best tools for accomplishing the task.

Plasma Cutting machines also come in Air or Gas models. They are preferred for cutting electrically conducting materials. They are the best for cutting rusted metals. They have a wide range of mechanizing. They are highly accurate in execution. Gas Plasma Cutting machines are very easy to handle and use friendly in many ways. They are very easy to operate as well. Thus eventually anyone can learn the art of welding quite easily, of course with proper protection. If not, the person can be severely injured. The Gas Plasma Cutters are constructed in the most optimizing possible ways. It has very basic features and operating techniques and thus eventually anyone can go through the manual and get accustom to its usage.

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Features of Gas Plasma Cutting Machines

Friday, February 18th, 2011

Plasma cutting machines are one of the most sought after machines today. They have established a name for themselves as one of the reliable machines involved in cutting of metals. The metals have a lot of applications you will find the best of machineries depending upon the metals because of their sturdy structures. To be able to construct these machines, one needs to cut the metals in different shapes and sizes. This is where the plasma cutting machines come into play.

Air/Gas Plasma cutting machine are also preferred due to its features like being able to cut electrically conducting metals. They also are efficient in cutting rusted metals. They have a range of mechanizing options and are also highly accurate with the execution. The gas plasma cutters are built in the most optimized manner possible and one would find them easy to operate. A simple read through of the manual and execution once would make one know its basic operations with ease.

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Features of Plasma cutting machines

Thursday, February 3rd, 2011

The advancement in technology is leaving no industry behind and has lead to the invention of plasma cutting machines which are considered to be of much use in welding and other industries. Plasma cutters have proven over time they are one of the quality tools for metal cutting. The plasma cutting machines are noted for their precision.

Plasma cutting machines may seem to be a touche expensive in the market when compared to other options, but what one must realize is that they do not compromise on quality. The plasma cutting machines are user friendly; they also are preferred for their efficiency and quality cut. Their efficiency and quality depend much upon a variety of factors like the material they work on, the gas used etc.

There are two types of plasma cuttersmanual and automatic which are commonly known and each has its own set of merits and drawbacks. So based upon your need, choose the apt plasma cutting machine instead of getting foxed by features you can do without.

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General information about plasma cutting machine!!

Friday, January 28th, 2011

In laymen terms plasma cutting is nothing but a process which can cut electrically conductive metal by using high velocity of ionized gas which is delivered from a nozzle. Plasma cutting is very apt for cutting steel and non ferrous material; it is mostly used by almost all industries and also by amateurs who are just beginners in welding. Generally plasma cutting machines are rated according to their ability to cut and its amperage. One basic thing which you have to keep in mind when you are buying a plasma cutting machine is that, if you want to cut thicker metals go for higher amperage cutting machine and if it’s of less thickness you can opt for lower amperage plasma cutter. The lower amperage cutter can cut thicker metals but it’s just that it won’t cut perfectly. So cutting with the apt cutter will give you a perfect finish in the cut.

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