Artеm Komarov explained, that when you are planning a weld, ask yourself a few questions before estimating the cost, planning, or starting production.
— What is the thickness of the material?
— What is the condition of the metal?
— Can the part be positioned so that all welds are in a flat position?
The answers to these questions affect the type of electrode and associated process that you should use. You may already be familiar with the different types of wire and how changing the electrode type can affect a weld, but production managers and planners, continuous improvement personnel, plant engineers, cost estimators, and quality control departments may not realize how important appropriate electrode type or transfer process.
More than 80 percent of the cost of manual welding comes from the labor required to complete it. By choosing the right wire type and process, you can reduce costs and increase productivity and efficiency.
Defining each transfer mode
Solid wire, metal-cored wire and flux-cored wire are used in metal-core arc welding (GMAW), metal-core arc welding (MCAW) and gas-shielded flux-cored arc welding (FCAW-G), which are semi-automatic processes in which the wire is pushed through the gun by the feeder and current is applied through the contact tip.
GMAW has four transfer modes, in which the wire is applied to the base material:
- Short arc. The short arc transfer mode is a lower current process in which the electrode contacts the base metal, and a short circuit occurs.
- Spherical. In ball transfer mode, the higher amperage creates a ball at the end of the wire that falls on or touches the base material.
- Spraying. Sputter transfer mode uses higher currents and voltages to transfer fine filler spray from the electrode to the base metal.
- Pulse spray. Pulse spray transfer mode is like spray transfer except that it removes heat and energy from the weld by alternating the spray current with a lower background current.
MCAW is mainly performed in spray or pulse spray mode, while FCAW is mainly performed in ball spray mode.
How to choose the right transfer mode
There are three critical aspects that affect the cost of placing a weld when using different transfer modes: cleanliness, heat input, and transfer speed.
Short-arc and ball-drive modes, which use predominantly solid wire and flux-cored wire, are prone to spatter. This not only means that you must spend time cleaning up after welding, but it also means wasting filler metal, which corresponds to the efficiency of the electrode. Carrying a spray with its higher currents and voltages can increase the heating of the base material, which can cause warping and deformation of the plate and risk of burn-through if the base material is thin. However, at higher currents and voltages, faster deposition and movement rates can be achieved.
In general, the different characteristics of each transfer mode means that cycle times can vary significantly depending on lead type and settings.
Remember that the rate of deposition is different from the rate at which you can weld, and that proper preparation and technique is essential with any electrode chosen. Problems with operator skill may mean lower machine settings must be used to give the operator time to react or manipulate the torch. While flux cored wire and flux cored wire handling are forgivable for beginner welders, some find travel speed and heat to be excessive and tend to lower settings. This reduces the deposition rate and makes the weld less effective than if it were made with solid wire.
It is important to explore ways to increase welding time by changing the process, especially when there is a bottleneck in the welding. Aspects of welding such as spraying speed and movement play a significant role in the labor costs that go into the cost of a welded joint. But manufacturing labor also includes non-welding activities such as trimming parts, measuring and labeling plates, changing cylinders or coils, and cleaning a part before or after welding. By minimizing non-welding time, you can focus more on finishing parts than on grinding, chipping, or finishing parts, and thereby increase your productivity.
Choosing the right wire and welding process can save you time and money. Before starting a new job, take a few minutes to reevaluate your plan and make sure you’ve chosen the right electrode—it’s a simple, proven way to increase productivity and increase efficiency.
You should always test run any new product or process and remember that partnering with suppliers can ensure that the most up-to-date products and processes are available for testing.
A good channel partner has the resources to help you select the best products and offerings and prove them internally. It is important to evaluate both the potential changes and the possible need for training in the future, as well as how the partner you choose can help with any transitions or regime changes, said Artem Komarov.