When operating under normal arc conditions, a stick electrode would work at around 20 volts. When you find yourself in situations like having to push the rod into a tight corner or a deep groove in an open root joint, you might encounter problems.
In these situations, your stick rod can live up to its name and stick when the voltage drops so low that the flame goes out.
What is DIG welding? DIG or arc control is a feature similar to hot start except the Arc force activates during the welding process and not just at ignition. When the welding machine picks up a potential short, it boosts current, preventing the flame from cutting out and stabilizing the arc to minimize electrode sticking.
DIG welding, otherwise known as Arc force control, allows welders with additional Stick arc control. This function will enable operators to shape the volt/amp curve to suit the type of joint and the type of electrodes chosen.
If you would like to understand more about how DIG welding works, we have tried to provide you with all you need to know.
Table of Contents
How Did DIG Welding Come About?
Manufacturers used to build welding machines to deliver a specific arc for specific applications and use them with certain types of electrodes.
At that stage, designing a welding machine to perform well in various situations was expensive and hard to achieve.
With the advances in inverter technology and microprocessors, manufacturers could create additional controls for the welder to make adjustments on the arc characteristics.
This feature meant that a welder could adapt the welder performance to suit the application and the electrodes chosen for use.
In stick-welding processes, these newer multi-purpose CC/CV inverters offer three options when operating in stick mode.
- Electrode type setting (E7018 versus E6010)
- Arc force control
- Hot start
Generally, the lower DIG settings are suited to smooth running electrodes such as the 7018, and the higher settings to suit the stiffer, deeper penetrating welding actions.
For example, the DIG makes it easier for a pipe welder to perform good penetration on an open root pass with an E6010 electrode.
How Does DIG/Arc force Control Work?
You may adjust your Arc force from a minimum to a maximum setting. Because a stick welder is designed to produce a constant output current, the welding voltage varies according to arc length and electrode type.
This variation may cause instability in some situations where electrodes have a minimum voltage they can perform at and still hold a stable arc. Arc force boosts welding power when it senses the voltage becoming too low.
The higher the Arc force, the higher the minimum voltage the power source allows, and it will also cause the welding current to rise.
At 0, the arch force is not operational, and at maximum Arc force, it is at about 20-30 A higher than the set welding amps.
This force is beneficial for electrodes that require higher operating voltages or common types that require a short arc length such as out of position welds.
Arc force allows you to increase the current when your voltage drops below about 20 volts, boosting powder and keeping your weld puddle molten and stopping your electrode from sticking.
With the DIG process, you close the arc length to get more power instead of opening it up.
The old technique on 6010/6011 was to whip and pause; in the DIG feature, you keep a short arc and use the Arc force to get the DIG you desire. (That is why some controls label the Arc force “DIG.”
Adjustable Arc Force Control and Electrodes
There are many different stick electrodes, and you need to match the correct rod to your welding project. When it comes to Arc force settings, the various electrodes have different requirements.
Generally, mild steels are suited to any E60 or E70 electrode, with 7018 being the most popular choice, and 6013s are a good choice from those starting in stick welding.
Related reading: Different Types of Welding Rods and Their Uses
To understand which electrodes suit the Arc force control function, the codes can be broken down as follows:
- The first two DIGits show the minimum tensile strength, so electrodes starting with 60 mean 60,000 psi tensile strength.
- The third DIGit shows which position the electrodes can be used during welding. The number 1 means that it can be used in any position, and the 2 means that they can only be used in the flat position.
- The fourth DIGit tells you the current you must use for the electrode and which coating the electrode has:
| DIGit | Coating Type | Weld Current |
|---|---|---|
| 0 | Cellulose Sodium | DCEP |
| 1 | Cellulose Potassium | AC, DCEP, DCEN |
| 2 | Titania Sodium | AC, DCEN |
| 3 | Titania Potassium | AC, DCEP, DCEN |
| 4 | Iron Powder Titania | AC, DCEP, DCEN |
| 5 | Low Hydrogen Sodium | DCEP |
| 6 | Low Hydrogen potassium | AC, DCEP |
| 7 | Iron Powder Iron Oxide | AC, DCEP |
| 8 | Iron Powder Low Hydrogen | AC, DCEP, DCEN |
To achieve consistent results, you need to understand the correct amperage and voltage on the type of rod you intend to run.
Related reading: What Does DCEN Stand for In Welding?
A 6010 needs a higher Arc force while a 7018 runs better on the buttery side, requiring less Arc force. Short arc increases amperage and decreases voltage, while long arc increases voltage and reduces amperage.
E7018 (low hydrogen) electrodes don’t require much Arc force under normal conditions, and operators should start on the factory/default setting and perform a test weld.
Related reading: 11 Common Welding Defects and How To Prevent Them
If the electrode does not stick and the Arc forces metal into the puddle, there is sufficient Arc force. If the electrode sticks, increase the Arc force by about 5 percent; if the arc is too harsh and starts to create splatter, reduce the Arc force.
Because each make or model of inverter performs differently, it is best not to use very high Arc force settings. Remember that an inverter’s Arc force only performs successfully in low voltage situations.
The proper arc weld length for an E7018 is about 3/32 inches from the weld joint (Using an ⅛ inch electrode). It can be challenging to maintain a tight arc.
The adjustable Arc force allows those who infrequently weld to achieve adequate penetration with minimal electrode sticking.
Another excellent application for Arc force is welding a close arc length or using a larger electrode at a shallow current setting to prevent the electrode from sticking to the weld material.
For example, when operating shielded metal arc welding (SMAW), your DIG will kick in at about 19 volts. When the voltage drops below 19 volts, your current will increase and will act to clear the short caused by low voltage.
Higher DIG settings are generally used on 6010 electrodes with a stiff arc, especially welding downhill on an open root joint. This function will help you push the bead into the root and reduce rod sticking.
In situations of running 7018, you would choose a lower DIG setting due to the globular transfer across the arc. These globs may cause a short when they move from the rod and touch the plate.
A good test to understand how the Arc force works is to conduct a simple test. Run a ⅛ inch diameter 7018 on a clean plate with the DIG set to its minimum setting.
Then perform an identical test with the DIG on maximum. You will see a large amount of splatter in your weld puddle, which is caused by too much clearing current.
Related Reading: The Problem With Weld Spatter – How To Stop It
What Settings Should I Use on My DIG Function?
Because different welding machines have different Arc force controls, you could take a general arc force effect at being:
Low Arc force setting: At its lowest settings, you will achieve a nice smooth arc with a small amount of extra force to help the rod DIG and not stick. This setting is excellent for the 7018 electrodes.
Medium Arc force setting: At medium settings, the amperage increases in the short arc length, and provides a snappier arc with more forceful DIGging.
Setting Arc Control vs. DIG Range >> Check out the video below:
Medium-High Arc force Force: This setting has an increased amperage and exerts more force than the medium setting, and the snappy arc is excellent for hard DIGging rods like the 6010.
High Arc force setting: This setting is great for more aggressive DIGging with the 6010, and it is almost impossible to extinguish your arc.
Conclusion
The Arc force/ DIG welding control can be really useful in eliminating many problems encountered in welding, such as shorts and the sticking of electrodes in the weld puddle
The Arc force can also ease the transfer of drops of melted material from the electrode to the base metal and stop the arc from a short circuit between the electrode and weld pool.
The Arc force is adjustable according to your weld surface and electrode specifications and can eliminate a lot of guesswork in the welding process.
The arc control feature can also be particularly useful in welding downhill on an open root joint or welding in a tight corner.
The adjustable Arc force can also help beginner welders achieve good penetration with minimal electrode sticking.
References
https://weldingproductivity.com/article/in-control/
https://www.polytechforum.com/metalworking/what-exactly-is-dig-setting-for-stick-welding-107641-.htm
https://www.mig-welding.co.uk/forum/threads/what-is-arc-force.35513/