The Various Ways of Knowing The Quality Of An Arc Welding Machine
Though some foreign welding machines are being used by the Structural fabricators and roadside welders in Nigeria, some of them still prefer the made in Nigeria type.
There is no significant difference in welded joints made by the foreign welding machine from that of the domestic type. Welding machines have various sizes and power outputs in both their foreign and domestic categories.
The issue that most arc welders face when trying to purchase a welding machine is knowing the best quality of the actual size they are buying. Â When a low-quality machine is used to weld thick metals the welded joint will not be strong because it will not fusion well.
For a welded joint to be strong the machine should be able to generate enough heat that can easily melt the two joints when they are close and its electrode passes through them.
Otherwise, only the electrode will deposit its melted content into the joint which is capable of holding the joint together but such a joint may break up later when heavy impact force fall or hits it.
For the above reason, let us discuss what a welder must decide before making a choice of the type of welding machine to be acquired, bearing in mind that the higher the quality and size the costlier it becomes.
WHAT A WELDER MUST CONSIDER BEFORE BUYING AN ARC WELDING MACHINE
What size of metals will the welder be working with frequently?
Yes, that is an important factor to avoid waste of resources, a welder that will be working on light steel plates that will not be thicker than 2mm will not require the same welding machine as a welder working with thicker steel plates and beams up to 10mm thickness.
Consider the chart below, it reveals the recommended voltage and current for each metal thickness during welding.
Therefore, to avoid waste of resources know your limit of working materials so that you can make the right choice in selecting the required machine.
What kind of electrode will be used frequently?
Knowing the size of the electrode to be used frequently by the welder will assist in making a better machine selection.
There are two popular welding electrodes in the Nigerian market, they are called the gauge 12 and the gauge 10 these two types of electrodes are the most common in the Nigerian welders’ material shops.
The Gauge 12 is smaller in size about 1.5mm in thickness while the Gauge 10 is bigger about 3mm in thickness.
It is not every locally made Nigeria welding machine that can weld the gauge 10 electrode effectively because of its thickness, such electrode requires high voltage, therefore needs a high-quality welding machine.
While the gauge 12 is the standard that most roadside welders use for their works.
What is the voltage of the public power supply in the workshop?
This is another factor a welder must consider before making a choice on the size of the welding machine to be acquired.
The domestic electric power supply in Nigeria is between 200volts to 220volts while the industrial electric power supply in Nigeria can be up to 400volts which is usually referred to as a three-phase power supply.
These two power supplies vary in terms of volts and current, and every welding machine has its voltage rating and acceptable power input, hence; it will be unwise to use a low quality or low voltage rated welding machine on the industrial electric power supply because it has the ability of causing severe damage to the machine.
Neither is it wise to use high quality or high voltage rated welding machine on the domestic electric power supply because it will definitely give out poor performance and can also damage the machine.
What type of welding Generator is to be used?
Yes, that is very important beside some industries that use larger power supplying generators, the popular generators used by welders in Nigeria are the S195 and the S1115 diesel generators.
They are all diesel engines but their power output depends on the size of the generator coil attached to them.
Basically, S195 can carry a 7.5 KVA generator coil which can carry the low-quality welding machines effectively and welds gauge 12 electrodes correctly, but it may not do well when using it for superior welding machines.
While the S1115 has superior power and higher RPM in its power output, therefore, it can carry up to 10 KVA generator coil which makes it ideal for superior welding machines and for welding gauge 10 electrodes.
Having gone through the considerations required to make your selection, let us discuss in detail things you must look out for in any size of the welding machine you will choose.
THINGS YOU MUST LOOK OUT FOR IN THE SELECTED MADE IN NIGERIA WELDING MACHINE
Power output:
Check the power output during the testing to know if it is the specified power and check how efficiently the power can weld the materials you will be using to work.
Also note that some of such machines can have their power output affected due to the power input, that is; if the voltage that went into it is low then the output voltage will also be lower than the specified rating.
But if the voltage is between 200-220volts and the machine is not giving out the specified power output, then the manufacturer may be lying about the machine, and make another choice of the same size.
End connections:
The end connections are the places where the wires used in winding the machine coils end and are being joined by another wire.
Experienced Nigerian welding machine manufacturers know that major discontinuity faults coming from the machine come from those joints.
Therefore the joints or the ends are usually brought out from the main coiling such that they are visible at the top edges of the coil, the reason is to enable the welder to easily connect the ends whenever they disconnect as a result of overheating.
Thereby reducing the maintenance cost and the stress for the welder in regard to the frequency of taking the machine to technicians for repair. So a welder should look out for such a design in the machine because it will be of help in the long run.
Padding technics:
This is the method by which all the metal sheets used in the making of the coils were padded.
The way the machine was padded is important if the padding has plastic plates on the outside then know that the plastic may melt after a period of time but if the padding was made with hardwood boards then it may last longer because it can withstand more heat than the plastic.
Metal plate thickness and sizes:Â
It is the thickness of the metal sheets used in the coil making which makes it form a kind of transformer design that makes some people call it a welding transformer.
The metal sheets are usually iron sheets while the outside will be attached with an insulator material such as plastic, fiber, or wood board.
It is assumed that low-thickness metal sheets in numerous numbers perform better in eliminating heat and increasing power output than a few high-thickness metal sheets used in the coil.
For that reason, consider selecting the machine with the low thickness metal sheets in their numerous numbers.
The material of the wire:
Most welding machines made in Nigeria usually come with copper or aluminum wires in their coils. The two types of wires used for the machine coils can perform very well in welding jobs.
The actual difference between the coil made of copper wire and that made with aluminum wire is size.
Coils made with copper wire are smaller than that of aluminum wire. And coils of copper wire do have higher power output, and durability and are more costly than the coil made with aluminum wire of the same size. So if there is an option to choose from the two go for the original copper wire coil.
The number of turns:
This one may be difficult to know since the welder may have no technical knowledge about it, however, the number of turns on the welding machine can reveal its quality.
If the turns on each coil are few and the wire is aluminum wires, then the machine will have low power output, unless such coil was made with original copper wire.
Insulation materials used:
Made in Nigeria welding machines do have insulators in them just like their foreign counterparts, the insulators may be plastic sheets, leather materials, papers, sealing tape, clothes, and latex materials.
Whatever material is used as the insulator the durability will rely on how the machine will be used, however, the types made of plastic, leather, clothes, and sealing tape usually last longer before bridging inside.
The base support and cooling system:
It is another important factor that many people overlook. The welding machine is like a transformer when a current pass through the welding machine the entire metal sheets in the coil will become temporary magnets which will make them attract any metallic object within the machine into the coil.
For this reason, experienced welding machine manufacturers in Nigeria usually make their machines have a solid insulator material on their base such that when the machine is in operation there will be a good gap between the coils and its metals from the ground, such design should be considered.
Also, the cooling system should be noted, for such a machine that has no top cover, the cooling system may be the atmospheric air while those with a top cover may have a small electric fan attached at one edge inside it so that it can help to expel the heats that will be generated in the coil into the atmosphere, so consider the two cooling arrangement and ensure one is in the machine.
The number of power outlets:
Just like the gears of a car, welding machines do come with different numbers of power outputs which may range from 1 to 5 or from 5 to 1 depending on the manufacturer’s arrangement.
Ensure there is a considerable number of such power output in the welding machine you want to buy otherwise you may have a problem when trying to weld extreme low gauge plates like the 0.5mm metal plates.
The difference in the number of turns for each voltage increase or decrease:
Having observed the number of the power outlets, consider the difference in the coil turns that led to the forming of each power outlet.
A closer number of turns for the outlet means a little or insignificant change in the outlet’s voltage.
But when the number of turns on the coil is much for each gap between the power outlets it will means significant power drop or increase, whenever the outlet socket is change.,
The thickness of the wire:
The thickness of the wire used in the coil making can affect the durability of the machine. Wires with small diameters tend to cut inside due to overheating during the welding operation, but the ones with a large diameter may not have a similar problem, so consider buying the type with considerable wire diameter in their coils.
Conclusion
These points highlighted above will aid any intending welder to make the right choice in selecting a quality arc welding machine.
