A very common occurrence in gas metal arc welding (GMAW) is the creation of what welders call “spatter,” which is essentially droplets of molten material that are generated at or near the welding arc. Spatter is generally regarded as a nuisance and is a critical factor to consider when developing an application.
Spatter can cause numerous problems in most manufacturing processes. The most common problems are:
Most manufacturers strive to reduce the amount of spatter generated, if not eliminate it all together. To resolve a problem you have to know why the problem is occurring – in this case what causes spatter.
Spatter is caused by several factors. The main factor is a disturbance in the molten weld pool during the transfer of wire into the weld. Typically, this is caused by the relationship between amperage and voltage. This is usually seen when the welding voltage is too low or the amperage is too high for a given wire and gas combination. In this situation, the arc is too cold to keep the wire and pool molten and causes a stubbing effect of the wire. This can occur at both high and low current ranges.
Spatter may also be generated as a result of the gas selected. In GMAW, the use of CO2 increases the arc energy and is very cost-effective, but it creates more weld spatter. Argon is commonly used to counter balance the spatter generated from CO2. Figure 1 gives a comparison of CO2 welding to MAG welding at different current levels.
Other patterns that can generate spatter include:
Most of these factors can be controlled or restricted through various techniques. Recent research conducted by DAIHEN Corporation has led us to new technological developments that have greatly improved curbing of welding spatter levels.
Additionally, there are a number of other factors that can worsen spatter generation. Some of these conditions relate to consumables, some are torch-related, and others are a reflection of production environments:
Usually, combinations of these factors cause an imbalance in the amperage and voltage. For example, oil on the parts being welded may cause a welding power supply to receive inconstant feedback and result in the power supply over- or under-compensating. To counter this, our D-Series come equipped with standard filtering systems to ensure a constant output of welding characteristics to control this relationship.
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